News Category: Knee

When joint cartilage is damaged and needs repair, surgeons can take a plug of cartilage and subchondral bone from a healthy joint and transfer it to the defect. A special tool called the Osteochondral Autograft Transfer System (OATS) is used to harvest the bone-cartilage plug. The graft is called autologous because it is taken from the patient. This technique has been used for several different sites such as the shoulder, elbow, and knee. In this report, surgeons from Germany examine the harvest site for plugs taken from the knee to treat the ankle.

There is some concern that taking these osteochondral plugs can have a negative effect on the knee. Even though the donor material is harvested from a non-weightbearing area in a healthy knee, it’s not replaced by normal tissue. Previous studies have shown that the donor site fills in with fibrous tissue rather than actual cartilage. That could lead to problems later — especially at the knee where the grafts in this study were taken from.

There have been a few long-term studies looking at donor site morbidity (problems and complications). But the number of patients included was very small. This is the first large study of over 100 patients who were followed for at least two years and some for as long as four and a half years. The authors thought that perhaps the number of grafts or the graft size harvested made a difference in the final results. It’s possible that taking larger grafts or a greater number (some had as many as three plugs transplanted) could negatively affect the outcomes.

What they found was that these factors had no bearing on functional results of the knee (the ankle receiving the osteochondral plug was not evaluated). Instead, a higher body mass index (BMI) indicating obesity was the major negative factor in the outcomes. A secondary factor was patient satisfaction. Two specific tools were used to measure function and patient satisfaction. The first was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The second was the Lysholm score. They also looked at age as a possible factor, but age did not have a significant effect on donor site recovery.

The WOMAC is a standardized set of questions that evaluates 17 functional activities. It was designed as a pain scoring system for patients with osteoarthritis. The Lysholm is a well-validated questionnaire used to evaluate knee function after injury (including after surgery). It includes questions about limping, need for support when standing or walking, locking or catching sensations within the knee, and stability (knee gives way). Previous studies of donor site morbidity following autologous osteochondral grafts for similar problems used these two measures as well. This helps researchers study and measure the same variables in the same way thus making research more consistent across the board.

A closer look at the results of this study showed that for every point increase in the body mass index, the Lysholm score dropped a point and the WOMAC scores went up slightly (an indication of worse function). The authors concluded that a higher body mass index is a negative predictor of outcome for the donor graft site. Surgeons should take this into consideration when planning osteochondral transplantation from the knee to some other area. Patients should be chosen carefully for this procedure with special attention to the presence of obesity. Patients who are overweight should be cautioned that this is a risk factor for less than optimal results.

If you have painful knee arthritis, exercising the knee may be the last thing on your To Do list. But studies like this one show that knee flexion and extension exercises do help. They improve strength and help your knee respond quickly to any change in position. The result can be less stiffness, faster walking speed, and a lower risk for falling. If you are a young athlete, that may not sound very important. But if you are an older adult, these benefits may grab your attention.

But exactly what kind of exercises should you do? Physical therapists from the School and Graduate Institute of Physical Therapy in Taiwan are investigating this. They compared the effects of weight-bearing (WB) exercises (feet planted on the floor) with nonweight-bearing (NWB) exercises (feet off the floor) to see which one might increase knee function more. A third group of patients with knee osteoarthritis formed the control group. They did not do any exercises.

For eight weeks, patients in the weight-bearing group exercised in a sitting position with one foot on a platform that gave resistance to flexion and extension motions. Patients in the nonweight-bearing group were also sitting. But the foot was free to dangle. A cuff was attached around the ankle with an elastic band attached. The elastic provided resistance to knee flexion and extension without putting any weight through the foot.

Everyone completed three exercise sessions a week. They did four sets of six repetitions of knee flexion and extension. They were able to rest for one minute between each set of exercises. There was a ten-minute warm-up period on a stationary bike before the exercise program and a 10-minute cool down with cold packs to the knee afterwards. Both legs were exercised (one at a time) with a rest break of five minutes in between.

Before starting the program, each person was tested using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The WOMAC provides a scale of function. The researchers also measured walking speed, muscle torque, and knee reposition error. All measurements were taken before and after treatment for a comparison.

Walking speed was tested over different terrains including stairs, level (hard) surface, spongy surface, and in a figure-of-eight pattern. Muscle torque was a test of knee extensor and flexor muscle strength using a special device called a dynamometer. Strength was tested at three different speeds of motion. The reposition error test was done by placing the lower leg in a set position between zero and 90-degrees of knee flexion. After moving out of that position, the patient was instructed to return to the same position (as closely as possible). The difference between the target (desired) angle and the reposition (actual) angle was the knee reposition error.

You may wonder what difference it makes if your feet are on the floor (weight-bearing) or not (nonweight-bearing) while exercising. Here are a few things physical therapists consider when setting up an exercise program for patients with knee arthritis. With the feet in contact with the floor, a compressive force is generated that goes through the ankles, knees, and hips. The result may be an overload that increases pain, swelling and inflammation.

And one thing weight-bearing exercises provide that nonweight-bearing exercises don’t is input or challenge to proprioceptive function. Proprioception is the (knee) joint’s ability to recognize what position it is in and then respond to any changes (even small changes) in joint position. That’s an extremely important function when you are walking on uneven ground, step on an object, or try to navigate a ramp or step off a curb.

The authors’ efforts to see whether or not weight-bearing exercise improves function more than non-weight-bearing in patients with knee osteoarthritis produced some interesting results. First, patients in both exercise groups improved in function and strength. There was an 18 per cent improvement in strength and a 50 per cent decrease in disability. The control group showed no change over the eight-week period of time.

The weight-bearing group did have improved walking speed in the figure-eight pattern and on spongy surfaces. They also had improved position sense compared to the nonweight-bearing group. The authors suspect that it’s the improved proprioception that made it possible to complete the more complex walking tasks faster.

They concluded that simple nonweight-bearing knee flexion/extension exercises are good and helpful in improving strength and overall function. This exercise regimen even helps improve stair-climbing skills. But appropriate weight-bearing exercises that don’t overload the joint are even better. That’s because the improved sense of joint position improves neuromuscular control of the knee on curved paths, over uneven floors, and when walking at a faster pace.

Although this study did not measure the effects of these exercise programs on falls, they suggest a future study may indeed find a difference in the risk of falling for older adults between those who exercise and those who don’t. And there may be a measurable difference in falls between those who do weight-bearing versus nonweight-bearing exercises.

Every orthopedic condition has a cause, effect, and then usually, symptoms that help point to the underlying problem. Meniscal tears in the knee are no different. Trauma or the degenerative effects of aging (cause) can lead to flattening and pushing of the meniscus out of the joint space (effect). Movement of the meniscus out of the knee joint is called extrusion.

The menisci (plural for meniscus) sit between the femur (thigh bone) and the tibia (lower leg bone). The menisci are sometimes referred to as the cartilage of the knee, but they really aren’t the same as the articular cartilage that covers the surface of the joint.

The two menisci of the knee work like a gasket to spread the force from the weight of the body over a larger area help the ligaments with stability of the knee. Without the menisci, any weight on the femur will be concentrated to one point on the tibia. But with the menisci, weight is spread out across the tibial surface.

Weight distribution by the menisci is important because it protects the articular cartilage on the ends of the bones from excessive forces. Without the menisci, the concentration of force into a small area on the articular cartilage can damage the surface, leading to degeneration over time.

In addition to protecting the articular cartilage, the menisci help the ligaments with stability of the knee. The menisci make the knee joint more stable by acting like a wedge set against the bottom of a car tire. The menisci are thicker around the outside, and this thickness helps keep the round femur from rolling off the edge of the flat tibia.

Without an intact, solidly attached meniscus, the knee joint space narrows down (result). Pressure from the two sides of the joint rubbing together cause bone spurs to form around the joint (result). Loss of the joint cartilage is another end-result of meniscal damage.

Eventually the person starts to notice pain, swelling, and problems with the knee (symptoms). Some even report a bone-on-bone sensation with walking or during other weight-bearing activities. That’s when they seek the help of an orthopedic surgeon.

In this article, Dr. J. M. Marzo from the Department of Orthopaedics at the State University of New York (Buffalo, NY) reviews the importance of the meniscus to normal knee biomechanics. A particular focus of the article is a tear of the meniscus at the posterior horn. A complete tear or rupture of the posterior horn is called an avulsion.

The front portion of the meniscus is referred to as the anterior horn, the back portion is the posterior horn, and the middle section is the body. The posterior horn is an important anatomical feature. Without it, stress on the meniscus is enough to cause significant load on the joint. That’s when the degenerative processes speed up.

How often does it happen that someone ends up with a posterior horn avulsion of the medial meniscus? It was once thought that this was a relatively uncommon injury. But with the availability of MRIs, doctors have documented a much higher incidence than previously thought. Up to 28 per cent of all medial meniscal tears involve the posterior horn. A large number of those (more than three-fourths) develop meniscal extrusion.

What can be done about this problem? Treatment often depends on the patient’s age, intensity of symptoms (mild versus severe), and activity level. The goal is to protect the knee joint and prevent degenerative changes that end up as painful knee arthritis. For the older, less active adult, it may be possible to get by with some activity modifications, antiinflammatory drugs (or just pain relievers), and weight loss for those who are overweight.

When it looks like surgery might be needed, the patient has several options to choose from. If at all possible, the surgeon tries to save the meniscus. Repair is preferred over removal. The meniscus is no longer routinely removed but rather reattached whenever possible. Rehab after surgery is important so if a patient isn’t willing (or able) to follow the surgeon’s guidelines, then surgery may not be successful.

If it’s not possible to repair the meniscus, then partial removal is considered. With complete removal of menisci that cannot be repaired, transplantation may be possible in a small, limited number of cases. Meniscal transplantation is referred to as a salvage procedure. The author did not say much more than that about transplantation.

But he did offer arthroscopic and MRI views of knees with degenerative medial meniscal detachment at the posterior horn. Diagrams and illustrations helped show how the surgeon can measure how much the meniscus has extruded (as seen on MRI scans). Dr. Marzo also provided his thoughts on the best way to perform surgery on patients with meniscal detachment. The goal is to restore the menisci’s ability to absorb stress and still support normal knee biomechanics.

The authors of this study offer some information that might suggest bone marrow stimulation before autologous chondrocyte implantation (ACI) may ultimately lead to failure of the ACI procedure.

Bone marrow stimulation techniques are used to treat a knee with a hole or defect in the articular cartilage. Articular cartilage is the rubbery, fibrous cartilage that covers the ends of bones to protect the joint. When the defect goes all the way down to the first layer of bone, it’s called a full-thickness defect.

There are different ways to stimulate the bone marrow to produce new chondrocytes (cartilage cells). Drilling into the first layer of bone under the articular cartilage is one. Shaving the surface of the bone called abrasion arthroplasty is another and microfracture is the third method currently in use.

All of these procedures have one thing in common. They are designed to fill the hole or defect with tissue from the bone at the bottom of the defect. This can help set up the repair process needed. A clot forms that eventually turns into fibrocartilage tissue. But the question is: if the surgeon does this repair technique and it fails, can the patient still have a transplantation of cartilage cells called autologous chondrocyte implantation (ACI)?

With ACI, normal, healthy cartilage cells (chondrocytes) are removed from a part of the knee joint that is not weight-bearing. They are taken to a lab where they are multiplied to form enough repair cells to put back in the defect and stimulate growth of the needed fibrocartilage. The cultured chondrocytes are injected underneath a special patch that has been placed over the hole.

The current belief is that marrow stimulation doesn’t prevent a successful ACI. They refer to marrow stimulation techniques as non-bridge-burning. The results of this study do NOT support that belief. What is this conclusion based on?

Surgeons from the Cartilage Repair Center at Harvard Medical School compared the results of 111 joints that had been pretreated with marrow stimulation before ACI with 214 (control) patients who just had ACI without marrow stimulation first. Some patients had more than one defect. And some of those patients had pretreatment with marrow stimulation while others did not. That made it possible to use patients as their own internal control to compare what would happen in one patient with both types of treatment.

They found that the failure rate after ACI was higher in patients who had first had marrow stimulation done (26 per cent in the pretreated group compared to eight per cent in the ACI only group). Failure meant the patient still had pain that limited function, MRIs showing that the graft didn’t take, and/or surgery had to be done to remove the graft.

Just defining what constituted a failure wasn’t really enough. They also had to look at the number of defects, type of defects, and defect size and location. Each of these variables had the potential to affect the outcomes. Likewise, it was necessary to compare each individual type of marrow stimulating technique to see if one was more successful than the others.

As it turns out, simple defects were more likely to be successful. The more complex defects had three times the failure rate of simple defects. The type of marrow stimulation technique didn’t seem to make a difference. The outcomes were about the same (equal failure rates) for all three methods (drilling, abrasion, microfracture). They did find that worker’s compensation patients had higher failure rates.

The authors concluded that treatment of full-thickness cartilage defects with marrow stimulation techniques can negatively affect later cartilage repair procedures. Patients who developed thickening of the subchondral (first layer of bone under the cartilage), bony overgrowth, and/or the formation of subchondral cysts after bone marrow stimulation were more likely to have a poor outcome.

Deterioration and failure of the bone marrow stimulation may occur because the new tissue forms over a thick, protruding, and stiff subchondral base. Eventually that subchondral plate starts to degenerate.

But this new evidence doesn’t mean surgeons shouldn’t use marrow stimulation techniques when they are called for. The majority of evidence shows a 60 to 80 per cent success rate with excellent results. Patients recover quickly with few postoperative problems and minimal rehab needed.

It’s likely that patient selection is an important factor in limiting failure rates. For example, there’s some evidence to suggest that large defects (more than 4 cm-squared) should just be treated first with ACI (i.e., skip the marrow stimulating step). Some experts have suggested that unknown biologic factors might set some patients up for failure no matter what. Maybe failure has nothing to do with pretreatment and everything to do with something else.

That leads us right into the need for future studies to look at the exact cause of failure. Is it really the increased mechanical stiffness of the subchondral plate, defect-specific factors, or patient-specific factors — or something else altogether? Scientists are just at the beginning of exploring cartilage repair and looking for minimally invasive approaches that won’t burn any bridges for later treatment.

Injuries severe enough to tear the anterior cruciate ligament in the knee often require surgery to repair or reconstruct the ligament. The timing of surgery remains under consideration. Should surgery be done right away? Does it matter how long someone waits before having the torn ligament reconstructed? What about this: does early surgery prevent meniscal tears and joint cartilage injuries? And conversely, does delaying surgery increase the risk of meniscal tears and joint cartilage injuries?

In this study, data from the Norwegian Knee Ligament Registry (NKLR) is used to answer these questions. In Norway, orthopedic surgeons send patient information to a central database on all patients having ACL surgery. Age, gender, date of injury, and date of surgery are recorded. The location and severity of any other injuries are also reported.

Almost 3500 patients were included in the study. All had ACL reconstructive surgery performed in Norway between 2004 and 2006. The time from injury to surgery varied from nine days to 40 years. Most of the patients had surgery within the first year after injury.

The patients were divided into three groups based on age at the time of the surgery. The authors expected some differences in results based on age. The youngest patients (children) haven’t finished growing yet. That factor could affect the results. The oldest group (41 and older) are subject to aging issues (degeneration) that could likewise make a difference.

Comparing the date of injury to the date of surgery and analyzing risk factors provided additional information. For example, age (older), gender (girls more than boys), and previous knee surgery were significant risk factors. For patients who had cartilage damage, the chances that they also had meniscal tears went up. The same relationship was true for those patients who had meniscal tears (meaning they were more likely to also have cartilage damage).

But most important of all, the data showed that for every month that goes by without surgery after an ACL tear, the risk of a cartilage lesion increased by one per cent. There were almost twice as many meniscal tears in the group who had reconstructive surgery late compared to those who had the operation within the first year. This relationship was true for adults but not for the children.

Surgeons often delay surgery in children until the growth plates have sealed up and the bone is fully mature. The results of this study confirm that the standard procedure of waiting until the child is at least 14 and/or reaching skeletal maturity before reconstructive surgery is probably a good idea. The delay does not seem to enhance the risk of meniscal and/or cartilage lesions.

Previous studies have shown that the timing of surgery should be determined by clinical signs and symptoms and function. For example, surgery is often delayed until swelling has gone down and motion is more normal. Other researchers have concluded that the condition of the knee at the time of surgery is actually more important than how long it’s been since the injury occurred.

The authors of this study agree with previous recommendations made that ACL reconstructive surgery should be done within the first 12 months of the initial injury. Following this timeline will help reduce the risk of meniscal tears and degenerative changes in the cartilage.

Meniscus (plural: menisci) in the knee depend on an intact and healthy anterior cruciate ligament (ACL). Without the ACL, forces on the meniscus increase up to 200 per cent. Protecting the meniscus is one reason why ACL tears are repaired.

The meniscus is a moon or crescent-shaped fibrocartilaginous structure present on both sides of the knee (medial and lateral). Both menisci provide structural integrity and support to the knee when it undergoes tension and torsion. Athletes involved in pivoting, cutting, or sudden changes in direction are most likely to sustain an ACL/medial meniscus tear. This commonly includes soccer and basketball players and skiers.

Treatment of meniscal tears has changed over the years from removal to preservation. Surgeons use arthroscopic methods to check the meniscus for damage. Any frayed edges are smoothed. Holes may be drilled with a tiny meniscus repair needle to stimulate bleeding and speed up recovery. The process of putting holes in the cartilage is called trephination.

The focus today is more on finding the best way to repair this structure. In this study, theFas-T-Fix device was used to repair vertical unstable medial meniscal tears in 27 patients. The Fas-T-Fix is an all-inside suture repair technique (different from the standard inside-out suture method). The sutures are easy to handle for the surgeon. Each suture has two attachment sites, which forms a closed loop. There are no sharp edges and they have excellent holding power.

Results are reported over a period of two to five years. Failure of the meniscal repair was counted as any patient who ended up with knee pain or problems and who had an arthroscopic exam confirming another tear of the meniscus where it had been repaired. There were six total failures out of the 27 patients (22 per cent). Anyone with a second meniscal tear was then treated with a partial meniscectomy (removal of the damaged cartilage).

The authors weren’t just looking at the final outcomes using the Fas-T-Fix. They also collected enough data about each patient to look for any trends or factors that might predict who would have a successful result and who would not. Failure was more common in acutely injured knees. In this case, acute described patients who had surgery within the first six months after the injury. Chronic injuries were defined as those that were repaired six months (or more) after the original injury.

They also took a look at the condition of the joint cartilage and joint surfaces while doing the arthroscopic exam and repair. Injuries in this area did not seem to have any connection with success or failure. The biggest factor appeared to be location of the meniscal tear. Most of the failures (four out of five) were located in the red-white vascular zone. That’s an 80 per cent failure rate for that zone.

There are three zones in the meniscus that correspond to blood supply to the area. The outermost zone is the red-red zone. Here there is the greatest amount of blood flow and the best chance for success. The middle zone (between the red-red and white zones) is the red-white zone. The inner zone is called the red-white zone. Healing potential is the poorest for tears in this central zone as this study confirmed.

The authors conclude that there are many things yet to consider in finding the best approach to ACL-associated meniscal tears. Failure of meniscal repairs increases with time from surgery. Patients who remain active after surgery figure into that factor. There are other suture repair devices besides the Fas-T-Fix. But the ease of intraoperative use with the Fas-T-Fix may result in more surgeons using this approach and with patients who should not be repaired with this device (e.g., red-white zone tears).

The patients in this study will be followed longer and results will be reported again later. In the meantime, more study on the problem of meniscal repairs and repair failures is warranted by the current high rate of failure reported in this and other studies.

Your knee creaks and hurts and it gets worse going up or down stairs, getting up after sitting a while, and when keeping the knee bent. Don’t even bother trying to squat. Sound familiar? You could be experiencing a condition called patellofemoral arthritis. Never heard of it? The authors of this article provide an in-depth review — everything you ever wanted to know about patellofemoral arthritis.

The patella (kneecap) is the moveable bone on the front of the knee. The underside of the patella is covered with articular cartilage, the smooth, slippery covering found on joint surfaces. This covering helps the patella glide (or track) in a special groove on the femur(thighbone). This groove is called the trochlear or femoral groove.

Patellofemoral arthritis occurs when there is a loss of the articular cartilage on the back of the patella and/or in the femoral groove. Wear and tear on the patella can occur anywhere but most often, the lateral edge (side away from the other knee) gets overloaded first. Experts think a slight tilt or malalignment of force contributes to the development of this problem.

Because the knee is in the middle of the leg, any changes in alignment from the pelvis down to the foot can create patellofemoral problems. The quadriceps muscle along the front of the thigh helps control the patella so it stays within its groove. If the quadriceps is weak for any reason, a muscle imbalance can occur. When this happens, the uneven pull of the quadriceps muscle may cause the patella to move more to one side than the other. This in turn causes more pressure on the articular cartilage on one side than the other. In time, this pressure can damage the articular cartilage.

Weakness of the muscles around the hip can also indirectly affect the patella and can lead to patellofemoral joint pain. Weakness of the muscles that pull the hip out and away from the other leg, the hip abductor muscles, can lead to imbalances to the alignment of the entire leg – including the knee joint and the muscle balance of the muscles around the knee. This causes abnormal tracking of the patella within the femoral groove and eventually pain around the patella.

Treatment for this problem has not been very successful in the past. But new understanding of the biomechanics (anatomy and function) of the joint have opened up new management techniques. The first step is to see a physical therapist. The therapist will design a therapy program to restore full, balanced strength and function of the hip and knee muscles.

Activity modification will be required. Avoiding stairs, squatting, jumping, and biking can reduce the load on the patellofemoral joint. Weight loss is always advised for anyone who is overweight. Reducing the stress, pressure, and load on the joint can be very helpful. Medications such as pain relievers and antiinflammatories may be prescribed. Occasionally, the use of steroid or hyaluronic injections is beneficial.

Some patients find relief from pain using a patellar unloading sleeve (a slip on neoprene support). Bracing or taping may also be helpful but studies are lacking in providing evidence that these measures really make a difference. Often, a combination of these nonsurgical treatment approaches works the best.

But, if after three to six months, there’s been no improvement, then some patients may be candidates for surgery. What can the surgeon do? Well, there are a variety of techniques that can be used. Which one is best differs for each patient and depends on the underlying cause of the condition.

In some cases, it’s just a matter of removing any bone spurs and smoothing the edges of the patella. Other patients benefit from the release of the lateral retinaculum. This is a fibrous band of connective tissue along the outside edge of the patella. When it gets bound down or tethered, it can create uneven pull and a restraint to the natural up and down movement of the patella.

If there are holes in the articular cartilage called defects, it may be possible to repair the damage. A newer technique called autologous chondrocyte implantation (ACI) has had favorable results. Normal, healthy cartilage is removed from a nonweight-bearing portion of the knee joint. The cells are taken to a lab where they are used to grow more cells. The cells are then transplanted back into the patient to fill up the hole.

Cartilage implantation has worked well for smoothing out the surface of the knee joint. It may not be as successful along the back of the patella. There are two main reasons for failure of this technique. The first is abnormal tracking of the patella. If the patella is not riding up and down in the center of the femoral groove, the same problem will develop again. Anything contributing to the malalignment of the patella must be addressed along with chondrocyte implantation.

Secondly, resurfacing the patella may be successful but the patellofemoral joint takes quite a beating everyday. There is a lot of pressure and load on the surface of the patella. The mechanics of gliding up and down over the femur put a much greater demand on patellar articular cartilage than even on the knee joint itself. The implantation may not be able to hold up under such rigorous conditions.

Other procedures that may help alleviate pressure from the patellofemoral include tibial tubercle transfer, patellectomy (remove the patella), and patellofemoral arthroplasty (replace the patella). The authors describe the indications and use for each of these operations.

Tibial tubercle transfer refers to the removal and relocation of the bump of bone called the tibial tubercle. This is the insertion point for the quadriceps muscle. The idea in transferring this area of bone is to change the pull of the quadriceps muscle on the patella and thereby reduce the load on the arthritic patella. The surgeon must plan this procedure carefully, using the results of X-rays, MRIs, and arthroscopy to determine what type of incision to use, where to make the incision, and how far to move the tubercle.

Treatment of patellofemoral problems is difficult. Disabling knee pain and patellofemoral breakdown may not respond to any of these limited surgical interventions. Sometimes it’s necessary to remove the patella completely. This is considered a more radical approach but it’s a simple and safe procedure that works. The down side is that the patient is left with a big loss in knee extension strength.

One alternative to just a patellectomy alone is a patellar replacement. A screw-on patellar shell is used to replace the patella once it is removed. Early efforts at patellofemoral replacement resulted in as many failures as successes. Newer designs and 3-D technology for designing the implant to fit the patient have improved overall results.

If all efforts fail to improve symptoms, motion, and function, then a total knee replacement (TKR) may be the final choice. This procedure is not advised for younger patients but reserved for older adults. Because of the abnormal alignment and mechanics that led to the patellofemoral arthritis in the first place, surgeons must approach a total knee replacement carefully. Imbalances must be corrected during the procedure to ensure optimal results.

What does the future hold for patients who develop patellofemoral arthritis in the years ahead? The hope is to identify contributing factors early enough to prevent this problem from developing. Short of that, restoring damaged cartilage is the focus of a new area of study called orthobiologics. And for those who end up with a patellar or full knee replacement, improved implant designs and surgical techniques will continue to provide satisfactory pain relief and restored knee function.

Can a healthy and normally aligned patella (kneecap) dislocate? Many experts have debated this question. Certainly, anatomic variations from the norm are linked with both acute (sudden) and chronic (repeated) dislocations. But there is some evidence that no amount of force will pop the patella off the knee unless there is an underlying reason.

In this review article, the anatomy and biomechanics of the normal patellofemoral joint as well as the abnormal patellofemoral joint are discussed in depth. A complete understanding of these features is essential in treating patellofemoral instability (dislocation) with any kind of success.

The patellofemoral joint is formed by the patella as it glides up and down over the front of the knee. This unique bone is wrapped inside a tendon that connects the large quadriceps muscle on the front of the thigh. The large quadriceps tendon together with the patella is called the quadriceps mechanism. The quadriceps mechanism has two separate tendons, the quadriceps tendon on top of the patella and the patellar tendon below the patella.

Tightening up the quadriceps muscles places a pull on the tendons of the quadriceps mechanism. This action causes the knee to straighten. The patella acts like a fulcrum to increase the force of the quadriceps muscles.

The underside of the patella is covered with a thick articular cartilage, the smooth, slippery covering found on joint surfaces. This covering helps the patella glide (or track) in a special groove made by the femur (thighbone). This groove is called the femoral groove.

Some people are born with a greater than normal angle where the femur and the tibia (shinbone) come together at the knee joint. This is called the Q-angle. Women tend to have a greater Q-angle than men. The patella normally sits at the center of this angle within the femoral groove. When the quadriceps muscle contracts, the angle in the knee straightens, pushing the patella to the outside of the knee. In cases where this angle is increased, the patella tends to shift outward with greater pressure. As the patella slides through the groove, it shifts to the outside. This places more pressure on one side than the other, leading to damage to the underlying articular cartilage.

Anatomic variations in the bones of the knee can occur such that one side of the femoral groove is smaller than normal. This creates a situation where the groove is too shallow, usually on the outside part of the knee. People who have a shallow groove sometimes have their patella slip sideways out of the groove, causing a patellar dislocation. This is not only painful when it occurs, but it can damage the articular cartilage underneath the patella. If this occurs repeatedly, degeneration of the patellofemoral joint occurs fairly rapidly.

People who have a high-riding patella are also at risk of having their patella dislocate. In this condition, called patella alta, the patella sits high on the femur where the groove is very shallow. Here the sides of the femoral groove provide only a small barrier to keep the high-riding patella in place. A strong contraction of the quadriceps muscle can easily pull the patella over the edge and out of the groove, leading to a patellar dislocation.

Any of these changes in the normal anatomical structure, especially when combined with enough force can cause the patella to dislocate. Changes in the Q-angle can result from any alteration of normal anatomy in the leg. One change alone may not be enough but with enough malalignment, the patellofemoral joint can be directly affected.

When examining a patient with patellofemoral instability, the orthopedic surgeon takes into consideration both normal and abnormal anatomical features and alignment. Sometimes comparing the uninvolved side helps identify the more obvious changes on the injured side.

The examiner views the patient in standing from all sides and again in sitting. The Q-angle is measured. The shape, position, and movement of the patellas are observed. Any signs of a lateral shift of the patella during movement called J-tracking are noted. The patella can be moved and tested for tilt and mobility (especially the presence of excess lateral motion).

X-rays may offer some additional information. Alignment, trochlear depth, and some important angles can be determined using X-rays. Loose fragments of bone or cartilage may show up on X-rays. Arthroscopic exams are much more likely to identify these loose bodies. MRIs are used to look for bone bruises and ligament damage. Patients who have chronically dislocating patellas may benefit from kinematic MRIs, which show dynamic images of the patella during movement. CT scans help identify anatomic variations that contribute to patellofemoral instability.

Treatment is based on whether the patient presents with an acute or chronic dislocation. The patient history helps determine what kind of acute injury has occurred. Most are when the person’s foot is planted on the ground and a force is applied to the knee that is strong enough to push the kneecap toward the outside (lateral) edge. The patella can dislocate medially (toward the other knee) but this is less common.

Usually the patella relocates or reduces (goes back in place) by itself. The patient may not even really be aware that the patella dislocated. But symptoms of swelling, bleeding under the patella or bruising around the patella, and tenderness along the edge are signs that a dislocation occurred. Surgery is required when there is severe damage such as bone fracture, muscle rupture, or detachment of the ligaments.

But surgery isn’t routinely advised. In some cases, conservative care is still possible with a period of immobilization (three to six weeks) or bracing with follow-up physical therapy. The therapist helps the patient regain motion, proprioception, and strength. Proprioception refers to the joint’s sense of position, an important function when maintaining joint stability.

The timing of surgery remains a point of contention. Some studies show that earlier surgical intervention yields a more favorable response with a much lower rate of recurrence. Undetected ligamentous and/or muscle damage can result in scarring of these structures during the healing process. This can have the effect of changing the force and direction of the patella when it moves, setting the patient up for future problems.

But not everyone agrees that early surgery is best. Enough patients have complained of pain after surgery that researchers are taking a second look at this approach. If there’s no difference in final outcomes between conservative and surgical approaches, then perhaps patients should be treated conservatively first and surgically later if needed.

What does if needed mean? Surgery may be necessary for patients who develop chronic instability with repeated dislocations. Then comes the next dilemma — what kind of surgery should be done? This may depend on any deviations present from normal anatomy, the amount of the Q-angle, and the results of imaging studies. The surgeon will also look at the condition of the soft tissues after the injury and the effect of trauma to the same soft tissues from repeated dislocations.

The general goal in surgery is to release tight lateral structures that pull the patella in that direction. At the same time, medial soft tissues can be re-tensioned or tightened up. Providing a balance of force and tension on both sides of the patella can help keep it lined up over the joint at rest, during motion, and when under stress from external forces.

One of the newer surgical approaches is to reconstruct the medial patellofemoral ligament that gets damaged with chronic instability. There is some hope that using graft material to restore the normal anatomy of this ligament will restore the normal function of the patellofemoral joint.

The authors provide detailed descriptions and drawings of the graft (and other) procedures under investigation. These newer approaches to chronic patellofemoral instability remain under study as early attempts have led to problems with pain, loss of knee motion, and degenerative changes to the joint cartilage. There is a need for long-term follow-up studies to prove the safety and effectiveness of new procedures before they can be adopted for routine use.

Given the belief that treating patellofemoral instability requires a good understanding of the anatomy and biomechanics of the patellofemoral joint, the authors offer a thorough review of these structures. Treatment with or without surgery is based on knowledge of these key features. Avoiding chronic instability depends on dealing with underlying causes for repeated dislocations. A careful examination and study of each patient can bring this into clear focus and direct the plan of care.

Why is it that most running injuries occur at the knee or in the lower leg? Is there some common factor that might be involved? The authors of this study set out to look for some answers to these questions. They didn’t do a study themselves of runners. Instead they turned to the literature and did a search of all the published articles on running injuries.

Research studies like this are possible now that everything is contained within an electronic database. Four of the most well-respected electronic databases (e.g., MEDLINE, EMBASE, PsychoInfo, CINAHL) were accessed for information on risk factors for overuse running injuries.

By doing a search with words like running, injury, mechanics. and knee, they were able to find 283 articles on running injuries published between 1980 and 2008. They narrowed the search down by looking for running injuries in long-distance runners who ran at least 20 kilometers (12 miles) each week. The athletes were recreational or competitive runners (not elite runners). They had been running at least one year (most much longer).

After analyzing the evidence, what they found was that there are two main reasons for overuse running injuries. The first is foot position called pronation. This describes an ankle that is angled inward and a foot that is flat (collapsed arch).

With a flattened arch, when the foot strikes the ground, the (flat) arch absorbs some of the shock that the heel would normally absorb in a foot and ankle that has a more normal alignment. If this misalignment occurs over and over with each stride, it can lead to foot pain as well as knee pain. Some runners develop pain up the front of the lower leg (shins) as a result of this transfer of energy on impact. This condition is called shin splints.

Studies have shown that a small amount of foot pronation during mid-stance (when weight is on the foot) works to the runner’s advantage. But too much for too long in the stance cycle and problems develop.
If the foot and ankle don’t roll back away from the pronated position, there isn’t a rigid enough column of support to allow for toe-off in the propulsion cycle. The tibia (lower leg bone) tries to compensate by rotating. The risk of injury goes up with the large twisting force placed on the lower leg.

Exactly how much pronation is too much remains unknown. This isn’t surprising since we really don’t even know what normal physiologic foot pronation is during unloaded (foot off the floor) and loaded positions (foot in contact with the floor).

Several studies have tried to look at this variable. So far, there isn’t agreement across the studies to show a cause-and-effect relationship between ‘X’ amount of foot pronation and injury. It seems there were just too many factors (e.g., running with shoes, running barefoot, having a prior running injury, position of the heel and rearfoot) that interfered with getting consistent results.

The second common risk factor in overuse running injuries of the knee involves the hip-stabilizing muscles. Weakness of the gluteus medius and other muscles that control hip internal rotation and abduction (moving the leg away from the body) play a big role in knee injuries.

When these muscles don’t stabilize the hip, the leg pulls into internal rotation. As the foot hits the ground, too much internal rotation increases the force placed on the arch and midfoot. The result is to transfer load through the foot and ankle up the lower leg to the knee. Multiple studies have shown the relationship of weak hip muscles to knee injuries. Even a small loss of hip abduction and external rotation due to weakness can affect the biomechanics of the lower leg.

Normally, as the hip moves toward the midline, the iliotibial band functions as a passive restraint system to hold the leg in a more neutral position. The iliotibial band is a long fibrous band of connective tissue along the outside of the hip. It goes from the pelvis to the tibia (lower leg bone).

Some of the hip muscles join together with the iliotibial band. When a runner with weak hip stabilizers runs, the iliotibial band gets overworked and they can end up with knee pain and/or iliotibial band syndrome (ITBS). ITBS is a painful lateral thigh from friction of the band against the muscle, bursa, and bone.

The authors conclude that the majority of overuse running injuries are caused by two basic problems: abnormal foot pronation mechanics and weak hip-stabilizer muscles. Armed with this knowledge, runners can be screened for these problems and start on a special rehab program before injuries develop from overtraining. If this theory is correct, rehab should reduce the large number of knee injuries that occur in runners.

Myth or Fact: Women take longer to heal and return to sports after knee (ACL) surgery later when compared with men.
Myth or Fact: No one should go back to full-activity or sports for at least six months after ACL surgery.
Myth or Fact: If you’ve had one ACL injury, you’re likely to have another knee injury.

Athletes of all ages involved in competitive sports have heard these statements as facts. But are they really? The authors of this article share their knowledge and experience after doing almost 3,000 anterior cruciate ligament (ACL) reconstructive surgeries.

Out of those 3,000 cases, 413 were middle school or high school athletes involved in basketball or soccer. Only athletes (male and female) 17 and younger were included in this study. Many played year-round on school and other travel teams.

The authors intend to follow these patients long-term and eventually report on a variety of results. Data collected included age, sex, and sport(s) played (before and after surgery). Everyone filled out a survey rating their function and activity level.

They watched to see how long it took the athletes to return to full activity, including team competition. No one was pushed to return to sports before they were ready. And they kept track of how many patients went on to play college sports. After the first year post-op, everyone was followed on an annual (yearly) basis. Any injuries to the other (previously uninvolved) knee were reported.

The players were given goals for rehab and guidelines for progressing through the program. The first goal was to reduce swelling and get full knee motion back. Once they had full range-of-motion, then they could be advanced to a strengthening program. Because basketball and soccer require fast moves, change of direction, pivoting and twisting, agility drills were added to the rehab program. When they were ready, recovering players were progressed to team drills and functional sports drills.

Players were told to pursue the rehab program as tolerated. They were instructed to monitor their own knee range-of-motion, swelling, soreness, pain, and tenderness. Any increase in symptoms or loss of motion was a sign that they should back off from their program and take it easy for a day. In the beginning sports drills and competition were limited to every other day.

Here’s what they found. First myth: Was there a difference between boys and girls in terms of healing and return to sports? No. An equal percentage of players returned to competitive sports after surgery regardless of gender.

Second myth: Was it necessary to wait six months before getting back into action? No. Many players completed the rehab program and returned to their former level of play as early as three months after surgery. And they did so without incurring future injuries (third myth). The average time for recovery was five months.

Some other studies do show a difference in results based on gender. But the authors suggest that age may have been a determining factor. Whereas the age of their patients was 17 and younger, the results of other studies are reported for adults. One other difference may be the way rehab was progressed in this study (as tolerated). Letting the athletes regulate their own pace (instead of pushing them too far, too fast) may be an important factor in a successful rehab program.

The authors conclude that boys and girls engaged in middle school or high school soccer or basketball return to their preinjury level of sports activities equally. A quick return to full sports after ACL reconstruction surgery is not a factor for early reinjury.

Athletes should be allowed to resume activities when they feel comfortable. Mild swelling and soreness may occur after activity and sports training. Knowing how to manage this and gauge subsequent activity is an important part of the recovery process.

Sometimes osteoarthritis of the knee only affects one side of the joint. When that happens, it’s called unicompartmental knee arthritis. Although either side of the joint can be involved, the medial joint (side closest to the other knee) is affected most often.

Surgical treatment for this problem could be with a tibial osteotomy. During this procedure, the surgeon removes or adds a pie- or wedge-shaped piece of bone. The osteotomy may be an opening wedge tibial osteotomy or a closing wedge.

Open wedge is used to create distance between the two sides of the bone. The result is to shift the weight away from the side of the osteotomy. In an opening wedge osteotomy, the surgeon cuts though the tibia (lower leg bone) on the medial side and opens a wedge, adding a bit of bone graft to hold the wedge open. The bone graft is usually taken from pelvc bone. The bone graft is held in position with a metal plate or pins.

In a closing wedge osteotomy, the surgeon cuts though the tibia on the lateral side (side of the leg away from the other leg). A pie-shape or wedge of bone is removed. Pins or a metal plate and pins are used to close the open edges back together. Closed wedge collapses the two edges of bone, thus shifting the weight toward the side of the osteotomy.

In either procedure, care is taken to protect the nerves and blood vessels that travel across the knee joint. The surgeon uses either X-rays or a fluoroscope, a special kind of X-ray machine to make sure the wedge is the right size and is placed correctly.

There are pros and cons with either technique. The goal is to shift the mechanical weight-bearing load away from the medial joint line and move the weight distribution more toward the middle of the joint. The intended result is to decrease joint pain and improve function.

The authors share the result of their experience performing the tibial osteotomy procedure on patients over the years. When they first started doing tibial osteotomies, they used a horizontal cut just above the point at which the patellar tendon attaches to the tibia (lower leg bone).

But they noticed that with this technique, the patella (knee cap) slipped down too far. This condition is called patella baja. The patella acts as a fulcrum or lever for the quadriceps muscle during knee motion. Without good alignment after tibial osteotomy, the result can be compromised.

So, the surgeons switched to using an oblique (cut at an angle) osteotomy right at the level of the patellar tendon insertion. The hope was that the change in technique would provide a possible solution to the patella baja.

Before and after X-rays were used to compare the results between using the higher horizontal wedge cut and the lower angled osteotomy. Patellar height, slope of the tibia when viewed from the side, and the weight-bearing line seen on X-rays were used as measures of results.

A detailed description of each surgical procedure is provided along with schematic diagrams to show what was done. The effect on alignment was demonstrated using photographs of the X-rays. The postoperative films were taken at least one year after the surgery to get a better idea of the long-term results.

There was no difference between the two groups in terms of size of osteotomy needed to treat the unicompartmental osteoarthritis. Patient demographics were similar except for age. Demographics refer to age, sex, education, etc.).

The group having the oblique osteotomy was younger. By the time they switched from a horizontal cut to an oblique osteotomy, other things had changed in how patients with unicompartmental osteoarthritis were treated. Older, less active patients can now have a partial knee joint replacement. Just the worn down side is replaced. Younger, more active patients have the tibial osteotomy instead. The osteotomy preserves bone and makes it possible to have a unicompartmental joint replacement later if needed.

The surgeons found there were many advantages to the oblique osteotomy. Because the cut was made lower down on the tibia, there was less disruption of the patellar tendon. The patella was also less likely to slip down. And this approach prevented unintentional damage to the nearby nerves and blood vessels.

Some things in the knee alignment didn’t improve with the change in location (lower) osteotomy. They speculate that using fluoroscopy to guide the surgery may help enhance their ability to correct angle deformities.

Loss of correction and delayed bone healing were two concerns after surgery. But the change in level of osteotomy didn’t seem to result in either of these problems. Perhaps the younger age of patients having the oblique osteotomy was a factor. The authors weren’t really sure the exact influence of age on final outcomes.

After all the X-ray measurements were taken of knee angles, alignment, and patellar position, it looks like the oblique tibial osteotomy with its lower angle is safer and more effective than the horizontal approach.

Patients and surgeons faced with how to treat a grade IV osteochondritis dissecans (OCD) defect have two choices: remove it or screw it back in place. In this article, the long-term results of a small number of patients (12) are reported following surgical fixation with a screw.

Osteochondritis dissecans (OCD) is a bone defect in a joint (usually the knee). OCD mostly affects the femoral condyles of the knee. The femoral condyle is the rounded end of the lower thighbone, or femur. Each knee has two femoral condyles, referred to as the medial femoral condyle (on the inside of the knee) and the lateral femoral condyle (on the outside).

Like most joint surfaces, the femoral condyles are covered in articular cartilage. Articular cartilage is a smooth, rubbery covering that allows the bones of a joint to slide smoothly against one another. The problem occurs where the cartilage of the knee attaches to the bone underneath. The area of bone just under the cartilage surface is injured, leading to damage to the blood vessels of the bone. Without good blood flow, the area of damaged bone actually dies. This area of dead bone can be seen on an X-ray and is sometimes referred to as the osteochondritis lesion.

In the case of these 12 patients, the knee was affected. A fragment of cartilage or cartilage with a piece of bone attached to it came loose and became a free-floating body inside the joint. The cause of OCD varies from patient to patient. The most common causes are repetitive microtrauma (most common in athletes), inflammation, loss of blood supply, and bone abnormalities.

The degree of severity depends on how large the fragment is and whether or not it has detached causing a hole in the bone where it came from. A mild (grade I) case of OCD means there’s a lesion but the frayed piece of cartilage is stable. In other words, it is still attached to the bone. During arthroscopic exam, the surgeon cannot move the fragment away from the bone. With a stage II lesion, the cartilage is starting to show some signs of separation between the cartilage and the bone.

Stage III lesions are partially detached. An MRI can be used to see just how attached (or detached) the fragment is. And with a stage IV lesion (the subject of this study), the fragment has come loose, leaving a crater or hole in the bone. This hole is referred to as a grade IV defect. The loose fragment of cartilage usually has a piece of the underlying bone still attached.

So the dilemma becomes: should the surgeon put the piece back in place and screw it in? Or would it be better to remove the loose fragment? After removal, the surgeon smoothes over the bone or fills the hole in with a bone graft or a cartilage implant. To help answer this question, the authors present the results of the fixation method they used in this small case series.

The surgeons searched their patient records to find all patients who were treated for OCD lesions requiring surgery. They were able to find 12 patients who had a grade IV defect that was repaired with screw fixation. Remember, this means the loose fragment was a layer of joint cartilage with bone attached from underneath.

The surgical procedure required the use of one to four metal screws. The screws were sunk down far enough into the cartilage and bone so that the head of the screw was flat or flush with the surface. The surgeon made sure there was a perfect fit between the loose fragment and the hole. If the fragment was too large, it was shaved and shaped to fit exactly. If the fragment was too small, they used extra pieces of bone packed in around the fragment to fill in the space.

The patients were instructed to move the knee but keep all weight off of it for 12 weeks. The nonweight bearing status helps the area heal without further disruption. At then end of three months’ time, the screws were removed. Screw removal required a second (arthroscopic) surgery. Arthroscopy allowed the surgeons to re-examine the area and see how it looked.

Early results were very good. Only one patient had a nonhealing response. That person had a second surgery early on (at 12 weeks) to repeat the fixation procedure. Everyone else had a stable repair. The surgeon used a probe to try and move the fragment and reported it was no longer loose.

The patients were followed for three to 15 years. Their symptoms, level of daily activities, and sports or recreational participation were recorded during that time. They were also asked questions about their quality of life (related to the knee) and overall knee function.

What did they find years later? There were no symptoms of osteoarthritis (knee pain with activity) and everyone reported normal function with daily activities.

The authors concluded that surgical replacement and fixation of grade IV osteochondritis dissecans works well and should be used whenever possible. Certainly, this method of repair is preferred to the other choice of removing the fragment. There’s a better chance that the patient will get close to normal anatomy and function with repair. Patients won’t get perfect results, as they may be limited in their ability to participate in sports activities without pain or stiffness.

When surgeons are reconstructing the anterior cruciate ligament (ACL) of the knee, they often see damage to the joint surface. The area affected is called the articular cartilage. This is the cartilage that covers the joint and makes it possible for the two sides of the joint to slide and glide smoothly across each other.

There is a question about whether or not surgeons should go ahead and repair these cartilage (chondral) lesions. Does it make a difference in the results of the ACL repair? Maybe it doesn’t matter and it’s best to leave these defects alone. We just don’t know yet which approach is best.

In this study, surgeons compared results between two groups of ACL patients: those with a chondral defect and those without. The patients with just an ACL rupture but no chondral damage were considered the control group. Patients in the two groups were matched by age, sex, and type of chondral injury. In terms of the cartilage injury, each patient had one defect rated as a grade 3 or 4 — that’s moderate-to-severe.

Everyone in both groups was treated the same way. First they saw a physical therapist for a preoperative program of rehabilitation. Then, the surgeon reconstructed the ruptured ligament using a bone-tendon-bone graft. This means they took a piece of tendon from some other area of the leg and used it to replace the damaged ACL. Then everyone went back to rehab after surgery. They all completed the same program of exercises. The cartilage lesion was not repaired and no special measures were taken to rehab differently because of the chondral lesion.

Everyone was followed for 10 to 15 years to see what the long-term differences might be between the two groups. The authors were unable to see a measurable difference between the two groups. The location of the lesion didn’t seem to change anyones’ function after surgery.

X-ray findings weren’t significantly different between the two groups. And tests of function using the International Knee Documentation Committee (IKDC) scores showed no major differences from one group to the other.

The authors remind us that there are still many unanswered questions about cartilage injuries. They don’t heal well and we don’t have very good treatments yet to encourage proper healing. The size of the defect doesn’t seem to make a difference either. The long-term effects are the same in patients with mild versus severe injuries.

The location within the joint articular cartilage doesn’t seem to matter either. Most of the lesions occur on the femoral condyle (bottom knob of the femur or thigh bone). But even when the lesions occurred on other locations, the results weren’t any different than for patients with femoral lesions.

Differences in knee score on the IKDC didn’t show up based on location of the chondral lesions. X-rays didn’t really show any signs of knee joint degeneration but this may be because of the young age of the patients and the fact that signs of joint degeneration don’t appear until there is quite a bit of damage.

Sometimes patients had to have another surgery after the ACL repair. There were different reasons for this such as loose fragments of bone or cartilage in the joint space, development of osteoarthritis, or continued joint misalignment. But the presence of the initial chondral lesion didn’t seem to be a factor in that.

Likewise, when patients complained of knee pain, stiffness, and giving way of the joint, patients in both groups were affected equally. So those chronic symptoms weren’t necessarily because they had a cartilage injury in addition to the ACL injury.

They concluded that deep cartilage defects that occur along with ACL rupture can be left alone. Treating them or not treating them does not give better results. And these lesions don’t seem to contribute to further joint damage or degeneration.

The authors would like to see more studies in this area before throwing the towel in on chondral lesions. It’s possible that some other (as yet unidentified) factor is important in the treatment decision about chondral lesions. Perhaps if we found a better way to treat the chondral lesions, the results would be improved.

Athletes suffer their fair share of tendon problems. Most often there’s knee pain from patellar tendon disorders or ankle pain from Achilles tendinopathy. Tendinopathy is another term for any disorder affecting the tendon.

In this study, a less common but equally disabling tendinopathy is examined: hamstring tendinopathy. The hamstring muscle is located along the back of the thigh. This muscle helps bend the knee and extend the hip. The muscle is made up of three main parts: the semimembranosus, semitendinosus, and the biceps femoris. The semimembranosus is the specific area affected by hamstring tendinopathy.

Surgery for buttock pain coming from the upper or proximal end of the hamstring is presented as a possible treatment option. This may be the first report of such an approach and its results. Athletes involved in sprinting and middle- to long-distance running events are affected most often.

Several questions are part of this study. First, when conservative care fails to relieve painful symptoms, can surgery help? And second, what’s going on in the tendon that’s causing this painful syndrome? If a tissue sample is examined under a microscope, what will we find that might help us better understand the problem?

Everyone in the study was diagnosed with proximal hamstring tendinopathy. Athletes between the ages of 16 and 63 (men and women) were included. Some were professional (competitive) track, cross country, or soccer athletes. Others were recreational sports enthusiasts involved in endurance sports such as running, mountain or rock climbing, and cross-country skiing.

Symptoms were similar for everyone: pain in the buttock area that was worse with activity and better with rest. Sitting for long periods of time would cause pain at the ischial tuberosity. That’s a bony bump also referred to as the sit bones. The term sit bones is used because you can usually feel them at the base of the buttocks when sitting on a hard surface.

No one had pain that went past the midthigh. Stretching the hamstring muscles often made the symptoms worse. Treatment was geared toward modifying aggravating activities. Sometimes complete rest was advised. Gentle stretching, antiinflammatory drugs, and physical therapy were also possible nonoperative (conservative) approaches to care. When those didn’t work, then surgery was considered.

Surgery involved first cutting the lower edge of the gluteus maximus (buttock) muscle. This allowed the surgeon to get down to the level of the hamstring tendon attachment to the ischial tuberosity. The portion of the hamstring muscle referred to as the semimembranosus tendon was then cut about three to four centimeters away from its insertion point on the tuberosity. This procedure is called a tenotomy.

The cut tendon and muscle were allowed to retract (pull back) away from the tuberosity. Then the surgeon reattached the tendon with sutures (stitches) to another part of the hamstring muscle (to the biceps femoris tendon). This is a way to shield the affected tendon from ongoing mechanical stress. The goal is to give the semimembranosus a chance to heal by protecting it from overuse.

The surgeon checked the sciatic nerve to see if there were any adhesions or fibrous strictures holding it from moving freely. There were a couple of patients who had minor adhesions around the sciatic nerve, which were cut free. But for the most part, the nerves in the area looked fine. And no one really had any sign of hamstring rupture at the time of the operation.

The authors provided detailed step-by-step descriptions of the operation with drawings to give the surgeon an idea of how to do the procedure. They took samples of the tendon tissue from 15 patients and compared them with normal hamstring tendon samples. The normal samples were from one young athlete who had been treated for a fracture of the ischial tuberosity.

Results were reported in two ways. First in terms of function, motion, strength, and return-to-sports. Second, based on histologic findings. Histology refers to how the cells look under a microscope. In the case of the first measurements, a majority of the patients were considered a surgical success. They could participate in sports activity at a level equal to (or better) than before their symptoms developed.

In a small number of athletes, pain and tightness persisted. They could no longer play at the same competitive level and had to reduce their activity to recreational participation only. Four of the 90 patients had to have a second operation because their results were considered poor with continued symptoms keeping them from pursuing their athletic careers.

What about the lab results? Did they find anything that would help explain what was going on? What they saw were changes in the cell structure to suggest tendon damage but not active inflammation. This was described as rounding of the tendon cell nuclei, increased ground substance (base material making up the tendon), and disintegration of the collagen (tissue) structure.

There were no signs of extra calcium, cartilage, or bone formation within the tissue samples. There were increased blood vessels to the area indicating an attempt by the tendon to heal itself. Added fat cells were interspersed between the bundles of collagen fibers. This suggests a degenerative process within the tendon. All of these findings were helpful in understanding why the semimembranous tendon looked thickened on MRI images.

The authors recommend using the term tendinopathy instead of tendinosis whenever the patient presents with pain, swelling, and impaired athletic performance caused by those symptoms. The old term hamstring syndrome to describe this condition is no longer used.

They say their histologic study sheds some light on tendinopathy as a pathologic process. Specifically, the lab samples support the theory that the tendon tried to heal but failed. Possibly repetitive stretching and overuse contributed to the damage done. The swollen and thickened tendon/muscle complex puts pressure on the sciatic nerve causing the painful symptoms. It’s not always clear when the pain is coming from the tendon versus from the nerve.

No one knows exactly why the semimembranosus portion of the hamstrings tendon thickens and creates this painful condition. When other areas of the hamstrings are affected, recovery is faster than when the semimembranosus is involved. Perhaps this portion of the muscle has a slower or decreased healing capacity compared to the other parts of the muscle.

The authors note that often proximal hamstring tendinopathy becomes a chronic problem before it is properly diagnosed. The delay makes treatment more difficult. Even with steroid injections early on, many patients end up with recurrence of the painful symptoms. This study doesn’t prove it, but it does present some evidence that perhaps early tenotomy may prevent future hamstring tears or ruptures.

This is just the start of researching ideas around this particular diagnosis. There are many other variables and factors to explore. For example, what’s the effect of eccentric muscle training on proximal hamstring tendinopathy? Eccentric refers to a process of lengthening the muscle from a shortened position as a means of strengthening it. This type of therapy has worked for other types of tendon/muscle problems. Research to explore other (less invasive) ways to perform the tenotomy should also be carried out.

For now we can say the surgical procedure of tenotomy as described in this study was both safe and effective in reducing pain from hamstring tendinopathy. Athletes were able to return to sports activities and avoid an early end to their athletic careers.

Much has been written about the evaluation and treatment of anterior cruciate ligament (ACL) tears. That’s because they are the most common knee injuries among athletes. Though less common, injuries to the posterior cruciate ligament are just as important. In this review article, surgeons from the New York University (NYU) Hospital for Joint Diseases bring us up-to-date on the important features of PCL injuries in athletes.

To better understand how PCL knee injuries occur, it is important to understand some of the anatomy of the knee joint. Knowing how the ACL and PCL work together to maintain stability and normal function is a large part of determining the optimal treatment for each patient.

The ACL and PCL are the two main ligaments that criss-cross and stretch between the femur (thigh bone) and the tibia (lower leg bone). These two bones join together to form the knee joint. Working together, the two cruciate ligaments control the back-and-forth motion of the knee.

The ACL keeps the tibia from sliding too far forward in relation to the femur. The PCL is made up of two separate but adjoining bundles of fibers. Each bundle has its own specific function. These bundles work together to keep the tibia from sliding too far backward in relation to the femur. They also control how much the tibia rotates externally (outward direction). Besides the ACL and PCL, there are other ligaments, cartilage, and soft tissues that surround the knee to help give it strength and stability.

There are two ways the PCL gets injured most often. The first is in a car accident when the passenger slams his or her bent knees into the dashboard on impact. The force and speed of the knee against a solid object pushes the tibia back underneath the femur. In a high-velocity injury of this type, the shear force is enough to rupture the PCL holding the tibia in place.

A second mechanism of injury (more common with athletes) occurs when the foot is planted on the ground and the knee hyperextends. Hyperextension means the joint is as straight as it can be and then a force pushes it into even more extension or overextension, thus the term hyperextension.

When the patient gives either one of these histories, the physician directs his or her examination to test the PCL. Several tests are commonly used such as the posterior drawer test, posterior sag, and the reverse pivot shift. The examiner will also check knee motion, quadriceps muscle function, and compare external rotation of the legs (the Dial test). The authors review each one of these tests (how to do them, what to look for, how valid and reliable they are).

Besides looking at the integrity of the posterior cruciate ligament, it’s important to evaluate if there’s been any damage to the blood vessels or nerves in the knee. Sensation, pulses, reflexes, and muscle strength will all be carefully reviewed.

Next, X-rays may be ordered. Any fractures or avulsion injuries can be seen on X-ray. An avulsion describes damage strong enough to pull a piece of bone away from the femur or tibia. The flat upper part of the tibia called the tibial plateau could also be fractured or damaged. Tibial plateau fractures are also visible on X-rays. Sometimes it can be difficult to tell if the PCL is partially or fully ruptured. Additional X-rays called stress radiographs and/or MRIs may be ordered for further clarification of the extent of damage.

Once the diagnosis has been made, then a plan of care must be determined. The severity of the injury usually guides who has surgery and how soon. For example, patients with avulsion injuries usually have surgery right away. The loose fragment of bone is screwed or stitched back in place with sutures.

Many players are actually able to participate in their sport with PCL-deficient knees. And they do so until the end of the season before considering surgery to reconstruct the knee and restore full stability. This is more likely to work when there is a partial tear, rather than a complete rupture. Undamaged supporting structures make it possible to continue functioning without a completely intact PCL. Keeping a strong quadriceps muscle is the key to successful recovery without surgery for mild PCL injuries.

Surgery is recommended when there is a chronic problem with pain and instability (e.g., the knee gives way under the leg). Instability because of multiple soft tissue injuries is more likely to cause enough problems to require reconstructive surgery. There are several methods used to reconstruct a ruptured PCL. The authors describe the transtibial approach, the inlay approach, the single bundle technique, and the double bundle technique.

Each of these surgical techniques was developed to overcome a specific problem or complications from one of the other approaches used. Some methods attempt to mimic the natural anatomy (e.g., double bundle reconstruction). Others, such as the single-bundle approach don’t try to reconstruct both bundles of the natural PCL.

Many surgeons prefer the double-bundle technique because it prevents posterior tibial translation better than a single-bundle approach. The double bundle reconstruction also shares the full load placed on the knee from all angles and through the full range-of-motion. But there are still some details to work out on the best placement of each bundle to mimic the tension placed on the knee by the intact PCL.

No matter what type of reconstruction is performed, there is always the risk of problems after surgery. The most common complication is a relaxation of the tendon graft used to replace the ruptured PCL. Because tendon harvested from someplace else in the knee is used to rebuild the PCL, there is more give than ligament and a greater chance of stretch.

A less common but more serious problem is damage to the nerves or blood vessels of the knee. Infection, osteonecrosis (bone death), chronic pain, and problems with any hardware used are also potential problems.

The authors conclude by saying that the fact that some athletes can recover without surgery tells us there’s much we don’t know about how the PCL works and which injuries don’t need surgery. Long-term studies are needed to show what happens for athletes with different degrees of PCL injury when treated with and without surgery.

The only way we will know how to advise patients about the best course of treatment is to follow injured athletes over decades to see what happens years later. Do they develop arthritis? Are both sides of the joint affected equally? Finding the optimal reconstruction technique for best possible outcomes is another long-term goal.

More and more younger adults (less than 60 years old) are getting total knee replacements (TKRs). Severe, disabling pain from degenerative joint disease is the main reason given for this type of surgery. And early reports indicate great success so far — a survival rate of the implant that was 82.2 percent for the first 15 years.

But is that survival rate really accurate? Is the whole picture being seen here? Dr. Andrew J. Price and associates conducted a study with much less favorable outcomes. The reason for the difference is the type of measurement used to define success.

Most surgeons use revision as the end-point of the implant’s life. Infection and loosening are the usual reasons an implant must be revised, removed, or replaced. But that’s a surgeon’s idea of failure. Patients are more likely to use pain as a gauge of success vs. failure.

And the results of Dr. Price’s study showed that most patients report at least moderate pain in the years following knee joint replacement. They aren’t pain free after all. Using revision OR pain as a criteria for the endpoint in implant survival, the rates fell to less than 60 per cent.

Dr. Price points out that revision (for any reason, not just infection or loosening) and pain are just two variables that can be used as an end-point in determining success versus failure of implants. There are others as well. For example, function such as walking, going up or down stairs, getting up and down off the floor, and even running could be used as measures of outcome in younger patients.

One reason revision rates are used as the final data on long-term survival of total knee replacements in younger patients is because there are so many other possible factors that can get in the way of gathering good data. The patient may have other health care problems referred to as comorbidities that could influence the results.

Other questions come up. For example, what cut-off date should be used during the follow-up? If using function as a potential endpoint in outcome, do we need preoperative assessment of function to show before and after results? Most tests of function do require before and after measurements in order to calculate the relative change in function.

That begs the question of which test to use to assess function. Dr. Price and his group of researchers used the Oxford Knee Score (OKS). The OKS is a self-reported pain measure. Patients rate their pain from zero (no pain) up to 48 (maximum pain). It isn’t really a test of function.

The researchers concluded that more study is needed to gather data on younger patients getting total knee replacements. Using only one measure of outcomes (revision) may not provide all the necessary information needed to determine the success rate of total knee replacements in this age group. This means the current reported outcomes of total knee replacements in younger patients may be too optimistic.

Infections after surgery can be severe and decrease the chances of a successful outcome. They also cause longer recovery time and costs more in medical costs due to extra doctor visits and treatments. Between one and 23 percent of people who have total knee replacements, or arthroplasties, end up with deep infections. For people who have revision surgeries, the rate is even higher, up to 6 percent higher and these infections even more difficult to treat.

The authors of this article wanted to evaluate the effectiveness of cement that was impregnated with the antibiotic vancomycin to correct the arthroplasty to see if it would prevent these infections from occurring in the first place.

Researchers looked at 179 patients who had 183 revision total knee arthroplasties between them. The majority of the patients had osteoarthritis of the knee, which made the original replacements necessary. All revisions were the first time they were done. The patients were divided into two groups: Group 1 was made up of 91 knees that received the usual cement, without antibiotics, didn’t use cement at all, or used a hybrid approach. Group 2 was made up of 93 knees that did receive the vancomycin-cement, didn’t use cement at all, or used the hybrid approach. Four patients in the study had both knees to be revised, so in each, one knee fell into group 1 and the other into group 2. All patients were given intravenous antibiotics before the surgery and some intravenous followed by oral antibiotics for several days after surgery. The average age of the patients was 70 years for group 1 and 71 years for group 2. The youngest patient was 49 years and the oldest 90 years. The most commons reason for the need for surgery was loosening of the hardware and/or wear and tear on the prosthesis.

The patients were examined and evaluated at three weeks after surgery, eight weeks, and six months. After that, the patients were seen every six months for an average follow-up period of about 89 months. The findings showed that although there were no infections in group 2, the group with the antibiotic cement, there were six deep infections and one superficial infection in group 1. Of the six, two were acute infections just after surgery and four were later, called late chronic. Overall, however, the average hospital stay period was about 13 days, ranging from nine to 17.

In discussing the study, the authors point out that while they don’t feel the vancomycin-impregnated cement can prevent infection alone, it is a good tool to be used with antibiotics before and after the surgery. They also point out that although they followed the patients for more than five years, they can’t tell if the effectiveness of the cement carries on and they would need further long-term studies for this.

The authors recommend that vancomycin-impregnated cement be used when doing a revision knee arthroplasty when the operating room lacks the necessary clean-air measures. They do note that further studies are necessary.

Have you ever heard someone say they tweaked their knee? Has that ever happened to you? You take a step wrong or move in just a way that causes a sudden, sharp pain along the inside (medial side) of the knee. You may have just experienced a grade I or II (mild) injury to the medial collateral ligament (MCL).

The MCL is made up of several layers of fibers. Some fibers are parallel. Others angle down from the lower end of the femur (thigh bone) to the upper part of the tibia (lower leg bone). The ligament is made up of multiple layers of fibers that cross the knee joint. It protects the knee from injury along the inside edge when a force is applied to the outside or lateral edge of the joint.

MCL injuries are among the most common knee ligament injuries. In this review article, orthopedic surgeons bring us up-to-date on current evaluation and treatment of MCL injuries. Most of the injuries to the MCL occur when the knee is slightly bent or flexed. Most of the time, people don’t even bother going to the doctor for this. If it happened to you, you probably just took it easy for a few days until the pain went away.

But when a more severe injury occurs or when this happens to a highly competitive athlete, early rehab is advised to protect the knee from further injury. A severe injury may cause a grade III sprain of the MCL. With knee dislocations or combined knee injuries, other ligaments and/or the menisci (knee cartilage) could also be involved.

The goal of treatment is to restore full function as quickly as possible. Return-to-sports is allowed as the pain goes away. Athletes often ask about the use of knee bracing to prevent these injuries or to prevent re-injury. There’s a lot of debate about this idea.

Some experts have expressed concern that bracing will cause the leg muscles to weaken and atrophy. Others think speed and agility will be compromised by bracing. Players often feel as though the brace gives them the support and protection they need to be able to play their best. But others complain that the brace holds them back and hampers their performance.

What’s the real truth about prophylactic (preventive) bracing? There isn’t much evidence from high-quality studies yet to guide us. What has been published so far shows that injury rates are lower for players at risk for MCL injury who wear a protective knee brace during practices and games. While providing protection for the MCL, the brace doesn’t really seem to limit function. That information should help put players’ fears to rest that their performance is negatively affected by the brace.

How does a player know for sure the MCL has been sprained? A medical evaluation is needed to make the diagnosis. The team physician or orthopedic surgeon will palpate (feel) along the medial joint line (side closest to the other knee). He or she will be looking for any pain, swelling, or tenderness. There is also a valgus stress test that can be performed specifically for the MCL. The injured leg is compared to the normal (uninvolved) knee.

The grades of sprain (I, II, and III) are based on how far the medial joint line gaps open during the valgus stress test. With a grade I sprain, there is minimal (less than five millimeters) of gap or opening. A grade II sprain means the joint line opens five to 10 mm and grade III has more than a 10 mm gapping effect.

Other tests are needed to rule out the possibility of additional injury to other ligaments such as the anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL). These two ligaments connect the femur to the tibia and criss-cross inside the knee. Depending on the force and type of injury, one or both of these ligaments could be damaged or even ruptured. For example, a force strong enough to dislocate the knee could cause injury to all the knee ligaments.

X-rays and MRIs are the most useful diagnostic imaging studies for MCL injuries. An arthroscopic exam may be needed to assess the overall integrity of the joint, meniscus, articular cartilage, ligaments, and other soft tissues.

Once all the damage has been identified, then a treatment plan can be determined. Conservative (nonoperative) care works well for grade I and II MCL injuries. Joint motion and strengthening exercises are the mainstay of this approach. Bracing is not advised during the healing phase of MCL injuries. Animal studies have shown that movement is important to ligament healing. Immobilization actually slows down the normal process of ligament repair.

A physical therapist or athletic trainer helps the athlete condition and train with a goal of returning to play as quickly as possible. Usually, this takes 10 days up to three weeks’ time. By the end of three months, the athlete should be back to a preinjury level of sports activity.

For athletes with more severe (grade III) MCL injuries, a trial of nonsurgical treatment is usually advised. But if the knee remains unstable despite muscle strengthening, then surgery may be needed. The surgeon uses the valgus stress test to help identify patients who continue to have too much gapping of the joint line, a sure sign of joint laxity (looseness) and loss of joint stability.

The type of surgery depends on the location and severity of the damage. Ligaments that pull away from the bone where they attach (either at the femur or at the tibia) are less likely to heal well (compared with injuries closer to the middle of the ligament–further away from the bony insertion sites).

It may be possible to repair minor tears but full tears will require reconstruction. The surgeon uses a tendon taken from the patient’s hamstring muscle and converts it to use as a tendon graft. When planning the operation, the surgeon thinks about the patient’s goals and expectations. The presence of other associated injuries (such as an ACL tear) must be considered as well.

Sometimes it’s possible to treat the MCL injury (grades I or II) nonoperatively but then repair or reconstruct the ACL surgically. Studies show good-to-excellent results with this approach. With an intact ACL providing joint stability, the MCL seems able to regroup and repair itself much faster. Two-thirds of the patients are able to return to full play and even maximize (improve) their performance.

Athletes should be prepared for the possible long-term consequences of combined injuries. Even with surgical reconstruction, there is an increased risk of osteoarthritis developing in that knee. There are also increased risks for reinjury and a second surgery.

Knowing this, researchers are now directing their studies to finding ways to prevent these complications from developing. It may be possible to identify subgroups of patients who should have an MCL repair or reconstruction rather than just conservative care. Right now, they are looking at the location of the injury, differences in recovery between groups who do have surgery and groups who do not, and the usefulness of MRI in predicting the outcomes of various treatment choices.

The authors conclude by offering their own approach to treatment for MCL injuries. All grade I and II injuries are treated with functional rehabilitation. Grade III MCL injuries are treated with nonsurgical efforts first. These patients are put in a knee brace and sent to physical therapy.

Surgery is considered when there is ongoing joint laxity resulting in chronic knee problems and instability. For patients with both an ACL and a MCL injury, the patient is given a brace, six weeks of therapy, and then surgery to reconstruct the ACL. The MCL is repaired only if joint gapping (more than four millimeters) is present after the ACL is reconstructed (tested while the patient is still on the operating table).

Hamstring injuries are fairly common in athletes or others participating in recreational sports. The injury can be fairly debilitating for a competitive athlete, requiring at least two weeks (and as much as six weeks) rest for recovery. And even with proper care, the recurrence rate for reinjury is fairly high.

In fact, there’s evidence that at least one-third of injured professional or amateur athletes older than 18 will reinjure themselves within the same season. The rate is much higher (60 to 70 per cent) for recurrence in future seasons. If that’s the case, then it seems that current treatment for this injury may not be effective.

Management of hamstring injuries usually centers around treating the acute injury and taking a look at risk factors. If any of those risk factors for injury can be modified, management should be directed to do so. This might be stretching and flexibility exercises for tight hamstrings or muscle retraining for muscle imbalances or muscle weakness.

In order to review how we approach hamstring injuries, it’s helpful to know what studies have been published on this topic and what they had to say. Toward that end, this group of physical therapists reviewed all of the literature published over the last 25 years on the topic of hamstring strains, injuries, pulls, or tears.

Their goal was to look for best evidence recommendations for prevention and treatment of this condition. Prevention centered on identifying and changing risk factors for injury. Treatment was identified as functional rehabilitation. Functional rehab is a way of treating the patient so that he or she can return to their individual sport fully prepared for movements required by that sport.

Over the years, investigators have looked at a variety of different potential risk factors for hamstring injuries. These have included muscle flexibility and strength, patient demographics (e.g., age, gender, educational level, type of sport), and a history of a previous hamstring (or other) injury.

It turns out the biggest risk factor for hamstring injury really is a previous hamstring strain. Athletes with at least one previous hamstring injury were two to six times more likely to have another similar (or worse) hamstring injury.

And most of those second injuries occurred soon after the first injury (within eight weeks’ time). But it’s not safe to say that if you have an initial injury and it’s been eight weeks without a second injury, that you won’t reinjure yourself. Many athletes (especially American football players) suffer a reinjury even a year (or more) later.

The hamstrings muscle is made up of several separate muscles/tendons. So one of the ways hamstring injuries have been investigated was to see if injurying one of those three parts put the athlete at greater risk for reinjury.

It turned out that the specific part of the muscle injured did NOT predict a second injury. So, that was no help. Then they looked at size and severity of the muscle/tendon tear. That didn’t appear to make a difference in the same season, but size (larger strains) was a risk factor for future reinjuries (within two seasons).

Since the hamstrings is just one part of the entire leg, it makes sense that an injury somewhere else in the lower extremity could put the athlete at increased risk for hamstring injury. That idea turned out to be correct. So anyone with a previous hamstring injury or other lower quadrant injury can be considered at increased risk for a hamstrings strain.

What about hamstring flexibility? It seems that hamstring flexibility isn’t as important as flexibility in other thigh muscles such as the quadriceps muscle (opposite the thigh along the front of the upper leg). Likewise, tight hip flexors (iliopsoas muscle) might make a difference. At least one study reported this factor was important in older athletes.

Of course, besides hamstring flexibility, researchers have also looked at hamstring strength as a possible contributor to hamstring tears. Studies have looked at differences in hamstring strength and body weight between athletes who got injured and those who didn’t.

The results of these comparisons have been more inconsistent and less helpful in identifying risk factors for injuries. Strength ratios vary depending on speed of leg movement and arc of motion. Leg length differences (one leg shorter or longer than the other) may possibly affect the measurements taken during muscle testing. These are what researchers refer to as confounding variables. Their presence muddies up the water so-to-speak, making it difficult to identify the real issues that make a difference.

Researchers have also looked at race/ethnicity as a possible risk factor for hamstring injury. There is some support for the idea that black athletes of all nationalities seem to suffer more recurrent hamstring strain injuries than other groups. The reason for this is unknown.

Playing position (outfielders) for kicking sports such as American soccer and Australian football is a possible risk factor. Level of competition rather than time spent on the field in training or playing was a risk factor. And fatigue at the end of the game has been linked with increased injuries. Playing conditions such as type of turf or condition of the ground or air temperature did not pose any increased risks.

Once the risks were understood, the authors turned their attention to the prevention and management of hamstring strain injuries. Despite efforts at hamstring strengthening programs, the results are not consistent among players or across sports. And strengthening programs are not carried out in isolation. The athletes are usually also stretching, running, and lifting weights. So, it’s difficult to measure the effects of a strenthening exercise protocol on hamstring function.

There was even a study looking at the effect of keeping the muscles warm with thermal shorts. Although players who didn’t wear the shorts were more likely to be injured, the rate wasn’t statistically significant. Players who wore the shorts once in a while seemed to have a higher rate of hamstring injury. But this could have been a coincidence or linked with something else (an unknown factor).

High-quality studies on the treatment for hamstring injuries are few and far between. The studies that were done often only followed athletes for a few weeks, so the rate of recurrence reported didn’t reflect the long-term results. The most success has been seen with functional rehab including progressive agility drills and trunk stabilization (core training) exercises. Again, the follow-up time reported for these studies was very short-term.

American football players with hamstring injuries are often treated with intramuscular corticosteroid injections and sent back into the game quickly (within a week’s time). But there is so much turnover in this group of patients that it’s difficult to get a handle on how many recurrences there are. A second hamstring injury may result in a player being traded or let go. Follow-up can be sketchy at best with this group.

Future studies of high-quality design are needed. And not just studies of professional athletes. Their level of play and tendency to keep quiet about their injuries may not be reflective of all athletes with these injuries. It would also be helpful to find out why hamstring strains recur. Other muscle strains don’t seem to have such a high rate of second injuries. What’s the difference?

The authors reflect at great length in their discussion of all the variables and factors that may lead to hamstring injuries and reinjuries. There are bits and pieces of the puzzle but the big picture just isn’t clear. There is some thought that athletes involved in kicking sports spend too much time and effort strengthening their quadriceps muscles, putting their hamstrings at increased risk for injury.

Muscle tightness is a particularly sticky subject. Most of these athletes are already on a stretching program. Are they really inflexible? Is inflexibility a risk factor or a result of previous injuries? Is it possible to test for hamstring tightness when it’s impossible to separate out lumbar, pelvis, and leg flexibility?

The authors conclude that our current knowledge and understanding of how to prevent hamstring injuries is limited. The same is true of how to treat hamstring strains. With more and more people involved in sports, it seems a good idea to find out more about how to prevent (or treat) these common injuries.

Sometimes orthopedic surgeons are faced with rare conditions they either haven’t seen before or have only treated a handful of times. Osteonecrosis of the knee is one of those problems. Osteonecrosis of the hip is a much more common problem. Developing diagnostic and treatment guidelines for rare conditions based on clinical experience isn’t always possible. That’s when physicians rely on articles like this one that provides a review of recently published literature.

Osteonecrosis is the death of bone tissue. There are three types of knee osteonecrosis: 1) spontaneous (occurs without a known cause), 2) post-arthroscopy (occurs after an arthroscopic procedure), and 3) secondary to some other condition such as lupus, use of steroids, or alcohol abuse.

Spontaneous osteonecrosis of the knee is also referred to as SPONK. It usually occurs in one compartment or section of the knee, while secondary osteonecrosis (caused by disease or medical therapy) affects more than one compartment. The bottom, round part of the femur (thighbone) called the femoral condyle is affected most of the time.

Spontaneous osteonecrosis usually occurs in patients older than 55 years, while secondary osteonecrosis can occur at any age. Women are affected by SPONK three times more often than men. The reason for this is unknown.

Osteonecrosis of the knee is rare after arthroscopy. It usually occurs when some form of heat such as laser or other thermal devices were used during the procedure. The patient starts to develop worse pain after arthroscopy than before. Knee swelling is a common feature of this problem.

MRIs are relied upon to identify and diagnose osteonecrosis of the knee. Bone scans are only reliable 56 per cent of the time. Osteonecrosis shows up on MRIs 100 per cent of the time. The main disadvantage of MRIs is the delay in findings after symptoms have started. Early on in the disease process, nothing unusual shows up on MRIs. The exact best timing for identifying this condition using MRIs remains unknown.

Once the condition has been diagnosed, then treatment begins. Everything is done to preserve the joint and prevent further breakdown of the bone. Early lesions can be treated conservatively (without surgery). The types of lesions that respond to nonoperative care have no low-density lines deep in the femoral condyles (as viewed on MRI scans) and no defects in the shape of the femoral condyles.

Patients are directed to avoid putting weight on the knee along with activity limitations. They must be patient as this protective process can take from three to eighteen months. Bone resorption may be stopped by the use of medications called bisphosphonates. Knee pain can be managed with analgesics (pain relievers). Treatment with bisphosphonates is fairly new and has not been proven effective for all patients yet. Further study of these drugs must be completed to guide the surgeon in knowing when and how to use bisphosphonates, as well as which patients would benefit the most.

Another newer drug treatment for knee osteonecrosis is tumor necrosis factor alpha (TNFA). This substance is injected right into the knee joint. Case reports show rapid (one-week later) improvement in pain and stiffness. Signs of healing are seen on MRIs after only one month.

But when the case is too far advanced or when nonoperative care doesn’t work, then surgery to repair the lesion may be needed. The type of surgery done depends on where the damage is located and how severe it is. The surgeon can drill holes in the bone, a procedure called core decompression. Debridement (scraping the damaged area) followed by bone grafting to replace the missing bone has also been tried.

Bone decompression combined with bone grafting may be one way to speed up healing and recovery. Biologic substitutes and tissue-engineered cartilage are two other proposed techniques for the surgical treatment of knee osteonecrosis. With tissue-engineered cartilage, the surgeon builds a scaffold with donated bone. The bone is cemented into interconnected pores. Then cartilage is used to repair the defect in the bone.

There haven’t been very many cases treated with these various techniques. So, which one works best and for what types of knee osteonecrosis are also unknown factors. The most information we have is on the outcomes using unicompartmental knee arthroplasty. In this procedure, the surgeon replaces just the half of the joint that’s been affected by the necrosis (rather than doing a full knee joint replacement).

Results reported from a limited number of studies report excellent results with this technique. Researchers consider the unilateral knee arthroplasty a very promising approach, but once again, more studies are needed to confirm these results and to see what happens in the long-run.

Right now, we only have limited information and understanding of what causes knee osteonecrosis and how to treat it. At the present time, research efforts are directed toward finding ways to preserve the joint, rather than replace it. Nonoperative treatments with new methods of tissue engineering may eventually provide a breakthrough in the treatment of this disease.