News Category: Knee

Athletes involved in all sorts of activities can suffer a complete tear of the hamstring muscle. The hamstring is the large muscle along the back of the thigh. It goes from the pelvis down to the knee. In this report, falls, waterskiing, running or sprinting, soccer, football, hockey, in-line skating, dancing, tennis, and wrestling were reported as the events linked with hamstring injuries.

There were 23 cases of proximal hamstring rupture in this study. Proximal refers to the place where the muscle attaches at the top. For the hamstrings, the proximal muscle attachment is to the ischial tuberosities — the bump of bone you feel in your buttocks when sitting down.

There are three separate tendons that meld together at this site. For a complete rupture, all three tendons are torn. The rip or tear could be anywhere along the muscle but this study focuses on tears at the ischial tuberosities. If it’s the tendon that is torn and the attachment is pulled away from the bone, it’s called an avulsion.

Treatment is based on several factors. First, how far from the bone did the tendon retract (pull away)? If the tendon only springs back a little bit (less than two centimeters), then surgery isn’t usually needed.

If the tendon pulls back more than that (and especially if it pulls a bit of bone along with it), then surgery is most likely needed. That’s because larger displacement of the tendon usually means more pain, weakness, and loss of function.

The surgeon also relies on the bowstring sign and MRI findings to make the diagnosis and determine the severity of the problem. A positive bowstring sign (indicating full rupture of the hamstrings) occurs when the examiner presses on the back of the knee just above the joint. There should be a cord of tendon that is easily felt on either side of the knee back there. But with a proximal rupture, the tension on the hamstring muscle is less so those tendons don’t tense up or form a palpable cord.

A second factor guiding treatment is how long ago was the injury? Chronic injuries (those that occurred more than a month ago) that are asymptomatic (no symptoms, no pain) can be treated conservatively (without surgery). But for the athlete with significant pain who can’t fully engage in his or her sport, surgery is indicated.

But to make sure that following these guidelines really provides the intended results, these surgeons followed their 23 cases for at least one full year (and up to nine years in some participants) to see what kind of results they got. When you think about it, there’s no sense having surgery if the results aren’t going to be better than letting it heal on its own. And that’s what this report is about.

Tests were done to measure muscle strength and endurance. Level of return to activity was reported along with any symptoms (pain, weakness, numbness, stiffness). One-third of the group had acute injuries repaired surgically within four weeks after the trauma. The remaining two-thirds were considered chronic because the injury occurred more than a month before the surgery was done.

The researchers looked to see if age (athletes ranged in age from 19 to 65 years old), sex (male versus female), and time-to-surgery (acute versus chronic) made a difference in the final results. The majority of patients (18 of the 23) had an excellent result with full return to their preinjury level of sports participation. Five athletes never had that full (100 per cent) assurance that they could engage in all activities normally.

Those same 18 athletes with excellent results had no symptoms of pain, stiffness, or numbness. Their strength was measured as equal to or better when compared with the other (uninjured) leg. Those athletes who achieved full return of hamstring strength and endurance got back into their sport faster. Larger hamstring tears seemed to lag in endurance but not necessarily strength. Age was not a significant factor.

As far as postoperative complications go, the 18 patients who reported an “excellent” result did have some loss of sensation around the incision site. There was also a puckering of the skin where the tendon was reattached but this was not painful. Four of the remaining patients continued to have numbness (sciatica) but these four patients had the sciatica before surgery and they were all in the chronic group.

In summary, there are still many debates about the need for surgery to repair a ruptured hamstring muscle. Some studies show poorer results when the surgery is delayed. Other studies report no difference between groups of patients who are treated conservatively (nonoperatively) versus those who have surgery.

The authors of this study suggest that larger tears observed in patients with a positive bowstring sign may be the best candidates for surgery. In other words, the degree of displacement or retraction of the ruptured tendon is a reliable factor in pointing to the need for surgery. Chronic injuries can and do heal and patients recover fully. Patients who have sciatica before surgery may not get relief from those symptoms.

It’s not surprising that a high-energy, traumatic injury to the knee can cause considerable damage. Ligaments like the anterior cruciate ligament (ACL) tend to go first. With greater intensity of force the damage can extend to the meniscus and medial collateral ligament (MCL). And now we know from this new study that before the meniscus or medial collateral ligament (MCL) give way, bone contusion (bruising) occurs first.

In fact, the more extensive the bone contusion, the more likely it is there will be associated injuries to other parts of the knee. A bone contusion (bruise) shows up on MRIs as increased fluid called edema inside the bone marrow (center of the bone). With anterior cruciate ruptures, the bone is usually bruised along the lateral border. Lateral tells us the area involved is along the side of the knee away from the other knee.

When the injury occurs, the foot is often planted firmly on the ground while the athlete is moving in a different direction. The intensity and speed of the event shifts the weight over the knee. The femur (thigh bone) rotates and the resulting shear force ruptures the ACL.

The exact mechanism by which the bone gets bruised isn’t quite clear yet. One theory is that bone bruising occurs as a result of a mechanism referred to as contrecoup. The contrecoup mechanism describes the motion in the knee as the knee shifts back to compensate for the first pivot-shift during the initial injury.

The discovery that bone contusion occurs during ACL ruptures was made by looking at MRIs of 81 patients who had an ACL injury that required surgery. Most of the people in the study were athletes engaged in their sport (soccer, basketball, baseball, volleyball) at the time of the injury. But there were a few who were involved in a fall or car accident. Everyone in the study had MRIs taken within six weeks of the injury. The MRIs were essential in determining that there had been bone bruising.

By taking a closer look at the MRIs in relation to the patients’ injuries, they were able to see how often bone contusions occurred. And, in fact, they found an 84 per cent rate of bone contusions in this group. By breaking the data down further, they recorded 73 per cent of the bone contusions were located along the lateral side of the tibial plateau. The tibial plateau is the flat shelf of bone at the top of the tibia (shin bone). The tibial plateau forms the bottom half of the knee joint.

There were almost as many (68 per cent) of corresponding bone bruises along the lateral femoral condyle. The femoral condyle is the round end of the bottom of the femur. There is a lateral and a medial femoral condyle (one on each side of the femur). The femur forms the upper part of the knee joint.

In a smaller number of cases, there was bruising along the medial femoral condyle (24 per cent) and on the medial tibial plateau (26 per cent). Bruises along both the femoral and tibial sides of the joint on the same side (medial or lateral) are called kissing bone contusions.

The surgeons were also able to identify how many patients had meniscal injuries (and what type) at the time of the arthroscopic surgery. About half of the group had some type of meniscal injury. They compared how many patients with bone contusions also had a torn or damaged medial or lateral meniscus. The greater the bone contusions, the more the meniscal injuries.

This makes sense if we remember the contrecoup mechanism. The initial injury damages one side of the joint. The knee shifts (rupturing the ACL) then shifts back (bruising the bone and tearing the medial collateral ligament). With enough force on the either side, the meniscus can be torn as well.

In summary, we’ve known all along that a lateral force on the knee intense enough to rupture the ACL is often enough to damage other aspects of the knee as well. This study shows how bone contusions (bruising) occur much more often than ever realized. With minimal force, there may be no bone contusion. With moderate force, the lateral side of the joint is affected first. And with severe force, there is enough energy behind the event to bruise the bone on both sides (medial and lateral).

Total knee replacements have been proven to last at least 15 years. But survival of the implant and knee function are too different things. And many total knee patients report persistent knee pain and loss of function despite the new knee.

Surgeons are exploring the reasons for this dilemma and looking for ways to improve results. One of those ways is to resurface the patella (knee cap) as part of the knee replacement procedure.

Resurfacing the patella involves shaving and smoothing the cartilage and bone along the back of the patella. Then the surface is covered with an implant made of metal, polyethylene (plastic), or a combination of both metal and polyethylene. Many surgeons favor the all-polyethylene backing as a result of studies that have shown there are fewer problems with it.

The present study was done to see if patellar resurfacing made any real difference. It was part of a larger study investigating the results of using four different total knee replacements. The larger study is called the Knee Arthroplasty Trial (KAT).

With over 1700 patients enrolled in the KAT study, this may be the largest research project looking at patellar resurfacing. Half the patients got a knee replacement with patellar resurfacing while the other half received the knee implant but did not have the patella resurfaced.

Results were compared between the two groups using pain, motion, and function as the main measures. There are several tests that give objective data to compare. The authors used the Oxford Knee Score, the Short-Form-12, and the EuroQoL 5D. They also looked at costs and compared the number of patients in both groups who had to have a revision (second) surgery.

After all the data was in and the number crunching was done, there was no difference between the two groups. After five years, presence of pain, pain levels, and the quality of life based on knee function were about the same for all patients in both groups.

Number and type of complications were also similar enough to be considered “no significant difference” between the two groups. And costs associated with the two procedures were fairly equal. There was a slight increase in charges because of the added patellar implant and slightly longer time in the operating room. But the statistical difference wasn’t enough to be considered significant.

What can we take away from the results of this study? Basically, that there is no detectable difference in clinical results between having a total knee replacement with or without patellar resurfacing.

The large number of patients involved in the study help support this idea that there is no obvious benefit of patellar resurfacing at the time of the knee replacement procedure. Surgeons may want to reserve patellar resurfacing for patients who continue to experience knee pain after knee replacement. Resurfacing the patella is a simple revision procedure that can be done later if needed.

The just-in-case factor is one practice in sports that is hotly debated. Should I wear a knee brace “just-in-case” I might injure my knee? This question arises any time an athlete participates in a contact sport with the potential for traumatic injuries. Add high speeds and difficult terrain in the dangerous and intense sport of off-road motorcycling and you may find yourself reaching for that brace, too.

But does a knee brace really protect you or anyone else participating in sports like off-road motorcycling? That’s the question raised (and answered) in this article. The information comes from a survey placed on the Internet and completed by over 2,000 off-road motorcycle riders.

Data was collected for one-year. Participants in track, off-road, motocross (MX), and other types of riding from around the world responded. Riders were asked about injuries (type, severity, frequency), riding hours, and use of prophylactic (preventive) knee bracing. The results were compared between riders who wore a brace just-in-case and those who did not.

They found that fewer injuries were reported by riders who wore preventive braces. Riders who didn’t wear a brace were more likely to injure their anterior cruciate ligament (ACL), the meniscus (cartilage) in the knee, or their medial collateral ligament (MCL).

All kinds of braces were worn so it was not possible to see if one type of brace worked better than another. The mechanism of injury was often using the knee as a pivot when coming around a corner at a high rate of speed. Landing with the knee over extended after a high-speed jump was another factor in knee injuries.

The authors make note of the fact that other studies similar to this one have been done in the past. But this may be the first in quite a while and the only one to be done after some of the newer braces have come out specifically designed for off-road biking.

By taking pressure off the ACL, these knee braces do seem to be making a difference in the number and severity of knee injuries. In fact, riders who do not wear a knee brace are twice as likely to suffer knee injuries compared with those who do wear the brace. That conclusion confirms the importance of prophylactic (“just-in-case”) bracing for riders engaged in any of these off-road biking events.

In this study, orthopedic surgeons from the Shelbourne Knee Center in Indianapolis, Indiana take a look at the results of treatment for a different type of knee meniscus tear. Their focus is on the posterior lateral meniscus root (PLMR).

This type of meniscal tear occurs most often when traumatic force is generated that is strong enough to rupture the anterior cruciate ligament (ACL) inside the knee. Along with the ACL tear, a posterior lateral meniscus root (PLMR) tear occurs.

With a PLMR type of meniscal injury, the main body of the meniscus (cartilage) is torn away from the root or its attachment to the bone. The tear is either straight across the C-shaped meniscus called a radial tear or at an angle (oblique tear).

As the name suggests, this type of tear occurs in the back portion of the knee along the outside edge. The more common meniscal tear is on the medial side (closest to the other knee). Medial meniscal tears are usually linked with degenerative changes in the knee rather than the traumatic ligamentous injuries associated with posterior lateral meniscus root (PLMR) tears.

What happens if the PLMR meniscal tear isn’t repaired at the time that the ACL tear is surgically reconstructed? Are the long-term results the same as, similar, or different from results for medial meniscal root tears? Those are the questions these researchers attempted to answer by comparing results five years after injury in two groups of patients.

The first group had a complete posterior lateral meniscus root (PLMR) tear. The second group was the control group — they had an ACL tear but without any involvement of the meniscus and especially no tears of the PLMR. Results were measured based on X-rays (showing joint space), level of pain, knee range-of-motion, and function.

Ten years after treatment, they found no statistically significant differences between the two groups. Yes, the patients with a PLMR tear had narrowing of the joint space along the lateral side. But this change did not seem to make any difference in function or activity for the PLMR group.

The results of this study do not answer the question of whether or not PLMR tears should be repaired at the time of reconstructive surgery for ACL tears. At the 10-year mark, it looks like leaving the PLMR tear alone is an acceptable treatment option. But what we don’t know is what happens after 15 years? or 20 years? Do these patients eventually develop osteoarthritis?

The authors note that PLMR tears are difficult to repair. There are nerves and blood vessels close by that could be injured during a repair procedure. Because of the location of the posterior lateral meniscus, the risk of further cartilage damage or damage to the opposing bone (femoral condyle) is high just trying to get the arthroscopic instruments into the area.

For these reasons, until there is clear evidence that PLMR tears should be routinely repaired, surgeons are advised to leave them alone. PLMR repair should be done only when it is clear that leaving the PLMR tear will yield a worse result than fixing it.

The results of this study will be held as a baseline. Patients will be remeasured routinely and results reported again. In time, it may become clearer just what the role of surgical repair for PLMR tears really is and when to recommend leaving the injury versus repairing it.

Athletes aren’t the only ones to develop knee pain from a condition called patellofemoral pain syndrome (PFPS). Many people of all ages in the general public develop this problem, too. You may be one of them.

If you have knee pain after sitting with your knee bent for a long time or with any of the following activities (stair climbing, squatting, kneeling, jumping, running), you may have patellofemoral pain syndrome (PFPS). How could you find out for sure?

PFPS is usually diagnosed by the history and an examination of the knee. If your pain is brought on by pressing directly on the patella (kneecap) when the leg is held straight or you experience tenderness underneath along the side edges of the patella, you may have PFPS.

Other telltale signs are pain with resisted knee extension and pain when the patella is compressed against the femur (thigh bone) when you tighten the quadriceps muscle (an isometric contraction) with the knee slightly bent.

What causes this problem? That’s been the focus of many, many studies. For sure there is a problem with the way the patella moves up and down over the knee. But what causes this maltracking?

There are many possible factors and it’s likely that more than one occur at a time. There could be an odd shape to the patella or an abnormal position of the patella. Or there may be some muscular imbalances — in particular in the quadriceps muscle. That’s the large muscle along the front of your thigh. It’s called “quadriceps” because it has four separate parts.

When the quadriceps muscle contracts and pulls evenly on the patella, it moves up and down over the knee joint in the middle where it belongs. But if the lateral quadriceps along the outside edge of the patella pulls more than the medial quadriceps along the inside border, then maltracking and eventually patellofemoral pain syndrome (PFPS) can occur.

To find out more about the role of the vastus medialis obliquus (referred to as the “VMO”) a group of researchers from Belgium conducted a new study. They used MRIs to measure the size of the VMO in two groups of people.

Group one were patients diagnosed with PFPS. They ranged in ages from 12 to 40 years old. Group two were considered “normal” controls — they did not have any knee pain and no sign of PFPS. They were matched by age, similar body type, activity level and sex (male and female).

Special equipment was used to hold the legs still so no muscle contraction would occur during the MRI test. The results were sent to a computer that had a special software program to measure and compare the size of the vastus medialis obliquus (VMO). The measurement was just muscle fibers without any fat, blood vessels, or nerves included.

They found that the cross-sectional area of the VMO was indeed smaller at the patellar level in the patients diagnosed with patellofemoral pain syndrome (PFPS). In fact, the entire quadriceps muscle was smaller in the PFPS group when measured at the midthigh level.

But these findings don’t answer the question: which came first — the PFPS or the change in muscle size? Maybe people born with a smaller vastus medialis obliquus (VMO) are more likely to develop PFPS. Or maybe the pain of PFPS leads to inactivity and the muscle begins to waste away and get smaller.

Understanding the cause and effect of VMO size and PFPS will be the focus of a future study. The authors also suggest looking at muscle strength as it relates to the size of the VMO in different people.

For now we know that there is atrophy of the VMO in patients with patellofemoral pain syndrome. This is new information that hasn’t been published before. And since we know the VMO is important in stabilizing the patella during knee motion, it seems logical that the smaller size of this portion of the quadriceps could be a key to directing prevention and treatment.

Osteonecrosis of the knee is a condition where a portion of the femur (thigh bone) loses its blood supply, dies, and collapses. Another term used for osteonecrosis is avascular necrosis. The term avascular means that a loss of blood supply to the area is the cause of the problem and necrosis means death.

This condition can affect other joints as well (e.g., hip, shoulder). When the knee is involved, the problem usually occurs on the medial femoral condyle — that’s the large round knob of bone (called a condyle) at the bottom of the femur. The medial condyle is affected most often. That’s the side closest to the other knee.

There are three separate types of knee osteonecrosis. The first type is called secondary osteonecrosis. It means the bone necrosis is caused by some other health condition. People who abuse alcohol or who are taking high amounts of corticosteroids are at risk for developing secondary osteonecrosis.

Organ transplant recipients, cancer patients, and patients with chronic rheumatoid arthritis receiving immunosuppressants for their inflammatory disease are also at increased risk of developing secondary knee osteonecrosis.

There are some theories about why these risk factors trigger osteonecrosis but no one knows for sure the actual mechanism between cause and effect. It’s likely that there is more than one factor at play. The bottom line is that something causes loss of blood to the bone and decreased blood circulation within the bone.

There is one form of secondary osteonecrosis that we have a greater knowledge and understanding of and that’s the kind associated with sickle cell disease (a blood clotting disorder). With sickle cell disease, red blood cells curl up and clump together creating a block inside the blood vessels. That blockage prevents blood from getting to the bone where it’s needed to supply the bone with oxygen and nutrients. the result can be osteonecrosis.

A second type of osteonecrosis is spontaneous. As the name implies, this type develops suddenly without warning. Most of the time only one knee is affected. Age may be a factor as most cases of spontaneous osteonecrosis occur in adults aged 50 and older.

Some experts suspect earlier knee trauma as the true underlying cause of spontaneous osteonecrosis. For example, mini-fracture of the layer of bone just under the knee cartilage (called the subchondral layer) may later become osteonecrotic.

Separately, there has been some suspicion that osteopenia (decreased bone density prior to developing osteoporosis) is also part of the initial process in spontaneous osteonecrosis. If it turns out that either of these conditions leads to osteonecrosis then this type of osteonecrosis won’t be called spontaneous any longer.

The third type of osteonecrosis of the knee is called postarthroscopic osteonecrosis. As the name suggests, this type develops after a patient has had arthroscopic knee surgery for some other problem.

Like the two other types of osteonecrosis, the actual reason why this complication develops remains largely a point of speculation and debate. It may be the type of instruments used during the surgery. Or it could be some type of unseen damage occurs in the meniscus or subchondral bone (remember, that’s the first layer of bone just under the joint cartilage).

No matter what causes knee osteonecrosis, the goal of treatment is always the same — prevent bone destruction and collapse. The patient is given medications for pain and inflammation and put on weight-bearing restrictions. Early diagnosis is good but even with early treatment, many people end up with severe bone destruction that is widespread (i.e., not contained in one or two small places).

Spontaneous osteonecrosis is the most likely to respond to conservative (nonoperative) treatment. If the lesion does not improve and get smaller with nonsurgical management in the first three months after diagnosis, then the surgeon may scrape the bone clean of any dead cells and give the joint a chance to heal. Transferring bone cells from a healthy part of the joint to the osteonecrotic section is another treatment option for spontaneous osteonecrosis. This procedure is called mosaicplasty.

In the case of spontaneous osteonecrosis, a unilateral implant (replaces just one side of the joint) is possible because only one side of the joint is affected. A total knee replacement may be more appropriate when severe osteoarthritis has developed on both sides of the knee.

Secondary osteonecrosis doesn’t seem to respond well to conservative (nonsurgical) care. Of the studies that have been done, 80 per cent of the patients went on to develop advanced stages of osteonecrosis.

Therefore, surgery is often recommended for secondary osteonecrosis in order to preserve the joint and prevent the need for joint replacement. The surgeon may remove the dead bone and replace it with bone graft material from a bone bank. This method may work well when there is only one small lesion. But there aren’t enough evidence-based studies to show this approach is best or prove there is a better way to manage the condition.

As for the treatment of postarthroscopic osteonecrosis, there is good news and bad news. The good news is that this type of osteonecrosis is very rare. The bad news is that with so few patients involved, there are no large studies of the problem. So, an evidence-based approach is missing.

Surgeons are currently relying on the results of several small studies to guide treatment. Conservative care can be tried at first. If that fails, then joint-preserving techniques may be attempted (bone grafting, microdrilling, mosaicplasty). As with spontaneous and secondary osteonecrosis, if the condition deteriorates and there is severe joint destruction, then joint replacement (unilateral or total knee) is the next step.

In summary, our knowledge of the risk factors, cause, pathology, and successful treatment approaches for each type of osteonecrosis of the knee is fairly limited. It is a progressive disease that can lead to arthritis and disability. More research is needed to understand the true nature of this disease and find ways to either prevent it from happening in the first place or treat it successfully when it does occur.

Anyone working with athletes suffering from patellofemoral pain syndrome (PFPS) will be interested in the results of this study. Strengthening the hip muscles first before working on the quadriceps (thigh) muscles speeds up the recovery process. Pain is less and function improved with this approach.

The study was done by a group of physical therapists, athletic trainers, and sports physicians at the University of Kentucky Musculoskeletal Lab. We’ve known for a long time that a weak, impaired, or imbalanced quadriceps muscle is a risk factor for patellofemoral pain syndrome (PFPS). But recent studies have shown that weak hip muscles (external rotators and abductors) are directly linked with PFPS.

The natural next step in research is to test the idea that strengthening just the hip muscles can positively affect PFPS. In this study, that’s what they did — they compared the results of hip strengthening exercises performed by one group of athletes with PFPS to a second group of similar athletes who did a quadriceps strengthening program instead.

All the participants in both groups were female. That was intentional because patellofemoral pain syndrome affects women twice as often as men in the general population and four times as often among athletes. So it’s important to test a group of female athletes. And in a way, it’s easier to test female athletes because there are so many around with this problem!

They carefully screened participants so that everyone had the same symptoms and clinical presentation. For example, everyone had pain underneath or along the front of the patella (knee cap). The knee pain was worse when climbing, hopping, running, squatting, kneeling, or sitting for a long time. There was no trauma or other knee problem causing the pain. No one in the study (either group) had ever had knee surgery. And everyone had knee pain for more than one month.

Results were measured using a couple of different outcomes. Pain intensity was one measure. Strength of hip and knee muscles was a second measurement used for comparison. They used a special handheld device called a dynamometer to test the muscles.

A third way to measure results was a test for functional strength. This test involved stepping down on one leg from a step, touching the heel to the floor, then returning back up to the step. The unit of measure used for comparison was the number of times each athlete could step down and back up in 30 seconds.

Before we look at the results, let’s take a closer look at the exercise programs themselves. Each athlete performed flexibility exercises (performing each stretch three times for 30 seconds each) before doing strengthening exercises. Then they did their program of (quad or hip) exercises three times a week. During one of those three times, they were supervised by a physical therapist or athletic trainer. The other two sessions were done at home on their own.

There were two phases of the rehab program. Phase one (flexibility and strengthening as described) lasted four weeks. Everyone was retested at that point before progressing to phase two. Phase two consisted of weight-bearing resistance exercises, balance exercises, and a continuation of either the hip or quadriceps strengthening (the same exercise program done in phase one). Following phase two (four weeks), retesting was conducted and the results reported.

Here’s what they found. Everyone in both groups gained in strength. Athletes in the hip strengthening group had less pain during the first four weeks compared with the knee group. The step-down test improved significantly for everyone in both groups.

They concluded that performing isolated hip strengthening helps decrease patellofemoral pain in female athletes faster than doing a traditional quadriceps strengthening program.

Doing either quadriceps strengthening or hip strengthening improved function as measured by the step-down test. The average healthy adult can perform 18 step downs in 30 seconds. Athletes in this study tested slightly below average (15 repetitions per 30 seconds) before rehab and improved to slightly above average (21 reps after rehab).

By the end of the study, the women in both groups had hip strength that measured close to normal. The authors noted the fact that they did not test a group with both sets of exercises at the same time or include a control group that did no exercise to compare the results.

You might not realize it, but the knee actually has corners. It may look like your leg is round on the outside but inside are complex bony and soft tissue structures in a location referred to as a corner. Injury to any of these “corners” that goes untreated can create a painful, unstable knee even after surgery for the presenting knee problem.

There are two corners in the front (anterior) and two in the back (posterior. Then add one from each side: medial (side closest to the other knee) and lateral. Combining front and side and back and side gives us corners named anteromedial, anterolateral, posteromedial, and posterolateral.

The corners of the knee are made up of a very complex system of soft tissues woven together. The way in which they share the load makes an injury of one ligament likely to affect the function of others as well. Sometimes where one ligament ends and another begins is impossible to tell. Likewise, many of the ligaments are attached to the joint capsule surrounding the joint (or to the joint itself) in very unique ways. Connective tissue called fascia is also part of the soft tissue structures that helps hold everything together at each corner.

In this article, the posteromedial corner (PMC) of the knee is the area of interest. In this corner are the posterior oblique ligament (POL), part of the hamstring muscle/tendon, the oblique popliteal ligament (OPL), and the back curved corner of the meniscus. Injuries to the PMC may go unrecognized and untreated. Often, an injury severe enough to damage the soft tissue structures of the PMC means there are other ligaments and soft tissue structures damaged as well.

For example, it’s usually pretty obvious if either of the main ligaments that criss-cross inside the joint are injured (posterior cruciate ligament or anterior cruciate ligament). Reconstructive surgery for either of these ligaments without repairing damage to the posteromedial corner may fail to take care of the problems (pain and instability). That’s when the surgeon goes looking for a multiligament and/or medial-sided problem to account for the ongoing symptoms. If the joint doesn’t line up as it should, then uneven forces applied to the joint can wear down the graft tissue used in the reconstructive procedure. The result may be a failed surgery.

As mentioned, traumatic force from an injury strong enough to tear one ligament is often enough to rip adjoining soft tissues. Identifying all areas of damage and injury is important in restoring normal biomechanics and function. How is this done? Surgeons rely on several tools. First, there is the patient history (how the injury happened) and the injury pattern (what was injured — muscles, tendons, ligaments, bone).

Then comes the examination. All of the physical findings are considered. Joint motion, areas of ligament laxity or looseness and any results from imaging studies (X-rays, MRIs) are reviewed. The final diagnosis and full extent of the injury/damage may not be clear until an arthroscopic examination is performed. With the patient relaxed under the influence of anesthesia, there’s no painful muscle guarding so the injury can be probed thoroughly. The surgeon checks for any movement that should not be there in the knee meniscus, tibial plateau, tibia, or femur.

Treatment depends on the diagnosis. Many problems are still handled conservatively with rest, support, medications, and activity modification. Mild medial-sided knee injuries (labeled grade I) affecting the corners usually don’t require surgery. The medial collateral ligament (MCL) has a healing capacity of its own. In fact, when there is a mild MCL tear along with a cruciate ligament tear, the surgeon may decide to postpone reconstruction of the cruciate ligament until the MCL has healed first.

Moderate-to-severe medial-sided injuries combined with other ligament injuries may not recover without surgical intervention. Whenever pain and limitations are still present six months later, surgical repair or reconstruction may be required. How does the surgeon put it all back together with everything woven together like in the natural knee? Is it possible to restore the natural biomechanics of the knee? Should everything be repaired at once? How long can surgery be delayed to allow natural healing but not compromise the structures that don’t heal on their own?

The authors conclude by saying these are all questions that are heavily debated in the literature. The main point is to make sure knee injuries are examined carefully enough to identify damage to the corners. The most common techniques for reconstructing the posteromedial corner of the knee are reviewed. Details are discussed regarding type of graft material to use (e.g., taken from the patient or from a donor bank) and fixation method (e.g., bioabsorbable screws). Photos taken during arthroscopic examination and open surgery are provided to guide the surgeon making repairs to this area of the knee.

So many people are getting knee replacements, it seems like a routine procedure any more. But there’s really nothing routine about getting the implant lined up with the mechanical axis of the bones and joint. And without an accurate placement of the implant, the joint replacement may not last as long as it should.

Surgeons are always looking for ways to improve their technique. Efforts are being made to improve implant alignment with knee replacement. One of the newest ways to improve total knee replacement surgery is with computer-assisted navigation.

Computer-assisted navigation uses an infrared tracker to help find the center of rotation for the femoral head. The infrared light helps the surgeon make bone cuts at exactly the right angle and thickness for the selected implant. X-rays taken after the procedure are done to verify the accuracy of implant placement.

Even though alignment is crucial to the survival of the prosthesis, there are other factors that affect how long a knee implant will last. Some are patient-related (e.g., age, activity level, bone density, body mass index or BMI). Some are surgeon-dependent (e.g., operative technique such as balancing the pull of opposing soft tissues during the procedure).

But matching the normal anatomic joint axes (where the bones and joint surfaces line up horizontally and vertically) is probably the one the surgeon has the most control over. Studies show that any deviation from the norm more than three degrees throws the joint off enough that uneven wear and force-to-load ratios increase. The result of these changes is loosening of the knee prostheses (implant).

This study is another one to confirm those findings but in a slightly different way. The authors performed total knee replacements on 32 adult patients who were having both knees replaced at the same time. Everyone received the same type of prosthesis and the same one in both knees.

In order to compare conventional surgery with computer-assisted-navigation, the surgeons performed the standard surgical procedure on one knee. The second knee was replaced using computer navigation.

Results showed a clear difference between the two methods with far superior results when using the computer-assisted navigation technique. In fact, when the surgeon used the computer program to help line the knee and implant up perfectly, there were no problems with axes angles (compared with a rate of 28 per cent in the conventional group who had more than a three-degree deviation from the norm). Only when a surgeon performed the procedure using the standard surgical techniques (without computer assistance) were there problems noted.

This information is helpful because there has been some ongoing debate about how well the computer-navigational systems work. Hospital administrators have asked if they are worth the cost and the extra operative time it takes to use it.

Patients have wondered if they aren’t putting themselves at increased risk for complications. But surgeons have persisted in trying to perfect this technique because the computer makes more accurate bone cuts and positions the implant more precisely. And the results of this study confirm that although the computer-assisted procedure took 30 minutes longer, there was no increase in complications reported.

The next step is to follow both groups and track their long-term results. Patients will be followed in order to measure mid-to-long-term survival rates of the implants. The authors also suggest conducting the same study with different types of implants and compare the results. But for now we can say the computer-navigated technique provides a more accurate alignment for total knee replacements without increased problems or complications.

This is the case of one 83-year-old woman who had a unicompartmental knee replacement that failed and had to be removed and replaced with a total knee replacement. The surgeons who did the revision surgery describe their technique. It is designed to help place the new implant with the right amount of rotation to prevent future uneven wear and tear.

The authors provide a bit of history about this patient, include X-rays of the unicompartmental implant, and describe their surgical technique for the conversion. Color photos taken during the procedure offer a step-by-step visual aid in understanding what they did.

Unicompartmental knee replacement (also known as a unicondylar knee replacement) is less invasive than a full knee replacement. The operation is designed to replace only the portions of the joint that are most damaged by arthritis.

This can have significant advantages, especially in younger patients who may need to have a second artificial knee replacement as the first one begins to wear out. Removing less bone during the initial operation makes it much easier to perform a revision artificial knee replacement later in life.

Since the time that unicompartmental replacements were first used, the design and surgical technique have improved quite a bit. The result has been an implant that lasts almost as long as the complete knee replacement. That’s good news for most patients.

But problems can develop as this case shows. The patient had significant osteoarthritic changes along the lateral side of the knee joint. That’s the side away from the other knee. With only one side affected by the degenerative changes, a unicompartmental knee replacement was a good idea. But three years later, she had such pain and disability that the decision was made to convert her to a total knee replacement.

Conversion can be a challenging procedure because the joint has been changed as a result of the first surgery. Anatomic landmarks the surgeon normally uses to line up the implant correctly aren’t always there. Balancing the pull of the muscles and tendons around the joint can also pose some problems.

The authors offer one way to avoid these problems during conversion. They suggest leaving the unicompartmental implant in place at first. Cuts necessary on the other side of the femur (medial in this case) are made first.

The amount of bone removed to put the unicompartmental implant in is checked by the surgeon to see if it was over- or under-cut. Then the bone is removed on the opposite side of the unicompartmental implant. This step is called bone resection. It is designed to make room for the total knee replacement implant.

The authors encourage other surgeons to avoid trying to even the two ends of the femur (thigh bone). Instead, bone graft can be used to lengthen the unicompartmental side if it is too short. As in this case, a special tool called a distal femoral cutting jig can be used to remove just the right amount of bone from the end of the femur.

In the procedure described, the bone on the tibial side (upper end of the lower leg bone) was measured and removed next. Again, the surgeon urges other surgeons to cut as little bone away as possible. They say don’t try to create an even or level surface from one side of the joint to the other. A metal wedge can easily accomplish the same thing without compromising the bone and potentially weakening the tibia.

The third step involves using a special sizing guide to judge the amount of external (outward) rotation of the implant as it is placed in the bone. Keeping the unicompartmental implant in place for this step makes it possible to get a better measurement of the rotation and any gap in the bone that will have to be filled in.

The authors also give alternate ways to measure femoral rotation during this part of the procedure. When everything lines up properly and all the guidelines match, then the femoral side of the unicompartmental implant can be removed and the total knee replacement put in place. Fewer errors are made when this approach is used to create the right amount of external rotation of the implant and proper alignment of the joint.

The surgeon will still have to check the muscular/tendon tension on the joint and make sure there is an even pull that mimics normal motion. Even balancing of the soft tissues is just as important as getting the right amount of rotation.

Although there aren’t studies to compare this surgical technique with others, this case study showcases the technique described. Other surgeons may find this method helpful in judging rotation of the femoral part of the implant when converting from a unicompartmental to total knee replacement.

Surgeons looking for ways to prevent infections in patients receiving a knee joint replacement will find this article of interest. Presented as an instructional course, the authors provide information on the incidence of periprosthetic infections, risk factors, diagnosis of infection, and management of the problem.

Periprosthetic infection refers to infection in and/or around the implant and joint in which the implant is located. Most of the infections are caused by staphylococcus aureus more commonly known as a “staph” infection.

Up to two per cent of the adults receiving a knee replacement will develop a periprosthetic infection. That number includes those patients who are diagnosed with an infection early on (first year after the procedure) as well as infections reported 10 years later.

Two per cent might not sound like much — and, in fact, it really isn’t a common complication. But there are two things that make this problem a problem. First, it can be difficult to diagnose and treat. A second surgery may be needed. Some patients end up having multiple revision surgeries.

And second, with the millions of Baby Boomers (born between 1946 and 1964) reaching senior status, it is expected that the number of knee replacements done in a year will rise significantly. That all means a two per cent rate could actually equal many thousands of patients affected each year.

The need to prevent periprosthetic infections is obvious. The way to do it is not so clear. Surgeons and patients both have a part in this potential problem. On the surgical side, it has been recommended that patients receive antibiotics one hour before the surgery begins.

Although staph infections can be picked up while in a hospital, many patients actually come to the hospital with their own bacteria because they are carriers and infect themselves. The prophylactic (preventive) antibiotics given before surgery help reduce self-infection. For the same reason, implants are coated with an antibiotic.

Patients who smoke, drink alcohol excessively, or who are obese are also at increased risk for periprosthetic infection. You might not think overweight or obese patients can be malnourished but the quality of what they eat isn’t always nutritional. Blood tests can help identify patients who are at risk for infection based on a poor nutritional status.

Malnutrition, urinary tract infection, and a history of diabetes, cancer, and rheumatoid arthritis are risk factors linked with joint infections after knee replacement. Anyone with a blood clotting disorder or taking medications to reduce clot formation (anticoagulants) must be watched carefully as well.

How does a patient know if his or her knee implant is infected? The first symptoms are constant knee pain, stiffness, and loss of knee motion. The presence of any risk factors raises the suspicion of infection.

Blood tests help confirm the diagnosis. The authors provide a detailed discussion of lab values used to assess patients for infection. Using inflammatory markers in the blood isn’t a cut and dried process. Early on after surgery, there are always increased levels of inflammatory cells as the body works to heal the surgical area. There’s a fine line between normal and abnormal elevation of blood markers.

Once it looks like an infection might be present, the surgeon removes a bit of fluid from the joint and has that analyzed. The results of the fluid culture may support a diagnosis of infection. But the surgeon knows that there can be false-negatives (i.e., test comes back negative when there really is an infection).

Antibiotic treatment is the first-line approach to management of periprosthetic infections following total knee replacement. Surgery is often a part of the plan of care as well. The surgeon cleans the joint out of any infection (a procedure referred to as debridement.

Any affected component parts of the implant are removed. Sometimes the entire implant has to be taken out. Repeated episodes of debridement are done until the joint culture test results come back normal once again. During that time, the surgeon puts in a spacer in place of the infected joint implant.

Once everything is cleared up and the cultures come back negative, then the surgeon inserts a new implant. Follow-up care includes continued antibiotics and close observation. Studies show a high rate of success with this protocol. Patients experience good long-term results with pain free, full, and smooth range-of-motion.

Who would have thought that hopping on one leg could be so helpful? During our younger years, playing hopscotch was just fun. But thanks to this study, we now know the importance of single-leg hopping when preparing athletes to return to their sport. This activity is especially important after surgery for an anterior cruciate ligament (ACL) tear.

The researchers (a combined group of physical therapists, athletic trainers, and sports medicine physicians) tested two groups of athletes. One group had completed rehab after ACL surgery. The second group played the same sports and were matched by age and sex (male versus female) but were healthy and without knee injuries.

Surgical techniques for ACL reconstruction have steadily improved over the years. So have rehab efforts on the part of physical therapists. The goal, of course, is to return the athlete to full performance as quickly as possible but safely (i.e., without reinjury).

That’s not as easy as it sounds. Often there are significant pressures placed on athletes from coaches, parents, teammates, and even themselves. The result may be the injured athlete gets back into the game too soon with less than optimal results and with an increased risk of another injury.

Can this be prevented? Yes, by ensuring the athlete has the power, strength, and agility needed for those vertical jumps, quick turns, and sudden changes in direction on the court or field. What’s the secret? Hopping on one leg.

After testing athletes with nine different tests, they found that three of those tests were sensitive enough to really measure differences from one leg to the other. The tests were the single hop, crossover hop, and triple hop.

Athletes who can complete these three activities during the final phases of rehab are ready to safely return-to-play. They must be able to do so with a performance on the injured leg that is at a level at least 90 per cent of the uninvolved leg.

What makes these tests so special or different? The key is the unilateral hopping (on one leg). Most training activities on the field are two-legged (broad jump, vertical jump, shuttle run).

When athletes are tested on two-legged activities, problems are masked. It turns out that being able to hop on one leg with speed and stability is a much more sensitive and accurate way to detect significant impairments.

The bottom-line is that rehab should not be so rushed that athletes recovering from ACL reconstruction are at risk for a second injury. Efforts should be made to equalize performance from side-to-side as a way to prevent future problems (including injury of the uninvolved knee).

Predicting when an athlete is ready for unrestricted, full activity following ACL reconstruction is no easy task. But the results of this study just gave us another reliable tool for ensuring a speedy but safe recovery. No sense going through all those weeks and months of rehab to blow it the first time back out on the court or field.

If you’ve watched any amount of sports, you may have wondered what those black or white straps around the athletes’ knees are for. Those are a form of patellar orthotics (bracing) called infrapatellar straps or bands. They are designed to reduce knee pain, especially in athletes who experience knee pain with running and/or jumping.

Do they work? And if so, how do they work? In other words, what’s the mechanism behind their success? This is the first study to really take a look at the effect of infrapatellar straps in the treatment of patellar tendinopathy.

The patellar tendon is part of the quadriceps mechanism. The quadriceps muscle is the large, four-part muscle that covers the front of the thigh. Contraction of the quadriceps muscle straightens the knee.

The muscle becomes tendinous around the patella (knee cap) and has its final attachment or insertion point just below the knee cap. The tendon and connective tissue around the tendon act on the patella like a pulley system to pull the tibia (lower leg bone). The final result of a strong contraction is a straight leg.

Repetitive contraction of the patellar tendon/quadriceps muscle can create local mini-trauma at the patellar tendon insertion point below the patella. This type of chronic strain may result in a condition of knee pain referred to as jumper’s knee.

As you might have guessed, it’s most common among athletes who are engaged in squatting, jumping, and running activities that require moving from knee flexion to knee extension. These are the folks most likely to be seen wearing an infrapatellar tendon strap.

The strap puts pressure on the patellar tendon with the hope of reducing the strain or tension at the point of pain. Despite how the strap looks, it’s not designed to actually push the knee cap up.

This study was done to find out what’s really going on with these straps. They also used this opportunity to compare one brand of strap to another (e.g., the Cho-Pat Knee Strap and the DonJoy Cross Strap).

Twenty healthy young men with no known knee problems participated in the study. X-rays of the knees were taken with and without each strap and with the knee in a position of flexion (60 degrees of flexion to be exact).

Measurements taken from the X-rays included one angle of the patella called patellar tilt, the angle between the patella and patellar tendon called the patella-patellar tendon angle or PPTA, and the thickness of the patellar tendon in three places. X-rays also showed any changes in the patella’s pressure against the femur (thigh bone).

They found that for most (but not all) of the men, there was a significant decrease in strain on the patellar tendon using either type of strap. No known reason could be found for the few men who showed no change with the strap.

The authors suggested perhaps there were differences in strap tightness or the level of strap placement. An alternate theory proposed was that there may have been some differences in tissue compliance (how much “give” there is in the soft tissue when the strap was applied).

It appears that the decrease in tissue strain is directly linked to the decrease in pain when using these straps. The X-rays confirmed that the patella was not pushed against the femur. The straps do increase the patella-patellar tendon angle (PPTA) and decrease the patellar tendon length.

One additional note about this study. Remember it was done on normal, healthy men without knee problems. The results may or may not be the same as if applied to patients with knee pain associated with jumper’s knee.

Before making any final conclusions, this same type of study must be done on symptomatic athletes. Likewise, the use of these straps to prevent patellar-tendon problems must be investigated. But finding out how the straps work on normal, healthy adults is the place to start!

Applying an electrical current to the quadriceps muscle may be helpful after anterior cruciate ligament (ACL) reconstructive surgery. Rehab results can be speeded up by using an electrical impulse to aid the muscle contraction. At least those are the results reported in this study from the Center for Knee and Foot Surgery Sports Traumatology Center in Heidelberg, Germany.

The use of electrical stimulation has been very controversial in the last 10 years. Some studies show it is helpful. Others report no benefit. Investigators are still sorting out when electrical stimulation to enhance muscle contraction (called neuromuscular electrical stimulation or NMES) is useful and when it’s not.

Some of the differences from study to study have to do with the type of patient involved, patient compliance (cooperation), type of neuromuscular electrical stimulation applied, and intensity of the stimulation.

In this study, three groups were compared. One group went through a standard ACL rehab program. Two other groups received standard rehab along with a neuromuscular electrical stimulation (NMES) program. There were two different types of devices used to apply the NMES: 1) conventional lead-wire Polystim and 2) a newer version called Kneehab (KH).

Polystim neuromuscular electrical stimulation is applied with four electrodes placed over the skin of the muscle. Each electrode is attached to a wire that goes to the electrical stimulation unit. The Kneehab device is a slip-on or wrap-around garment that incorporates larger electrodes into the sleeve. The Kneehab can be put on and taken off in a matter of seconds.

Neurostimulation (with both types of unit) was used three times each day on five days out of seven each week for three months. While the polystim and Kneehab units applied electrical stimulation, the patient contracted the muscle with as much force as possible.

The treatment provides a two-way reinforcement to recovering muscles. The goals of treatment were to regain strength, recover knee motion, and reduce inflammation. Hopping and running tests were used to measure results as these activities require joint function, strength, and muscular control.

The patients in all three groups were tested and retested over a period of six months. Everyone also kept a diary of their daily exercise, overall rehab program, and when they reached their goals (e.g., return to daily activities, return to work, return to sports).

The patient diaries showed that compliance was best in the rehab only (control group who did not use electrical stimulation). The information on exercise was by self-report for the exercise/rehab only group.

Patient compliance was easily verified in the two electrical stimulation groups because the stimulator devices have a data readout program. Compliance was considerably better in the Kneehab group.

Here are the key results reported: 1) performance was at its lowest for all three groups six-weeks after surgery, 2) patients using the Kneehab had the greatest strength return at that six-week marker, 3) results gradually improved after that for everyone in all three groups, 4) patients receiving neuromuscular electrical stimulation (NMES) outperformed the rehab only (control group) at every point of the study.

The authors conclude that neuromuscular electrical stimulation used along with rehab is an important training tool. When used after anterior cruciate ligament (ACL) surgery, patients obtain better results faster.

It appears that an important factor is the use of electrical stimulation early in the rehab and recovery phases following ACL reconstruction surgery. Analysis of results suggests improvements and speed of recovery are faster when strength is addressed early in the rehab timeline.

Patients in the Kneehab group returned to work a full week sooner than patients in the other two groups (control/rehab only group and Polystim neuromuscular electrical stimulation group).

What’s next? The authors propose two other research ideas using neuromuscular electrical stimulation. One with other types of knee surgery such as knee replacements and another using neuromuscular electrical stimulation combined with a rehab program before knee surgery.

With the new Kneehab device, ease of application and ability to record patient compliance makes research all the more convenient. Claims that it can be used to help avoid or delay surgery must be investigated further.

Surgeons treating patients with anterior cruciate ligament (ACL) tears are always advised to look for damage to other knee structures during the arthroscopic exam. Now there is one more thing to look for: ramp lesions.

What’s a ramp lesion? It involves the medial meniscus, a C-shaped piece of thick cartilage inside the knee. There are two of these protective liners: medial (side closest to the other knee) and lateral (side away from the other knee).

A ramp lesion occurs when one particular edge of the medial meniscus (near the posterior or back portion of the cartilage) comes loose. The tear is located where the meniscus meets the synovium (lining of the knee joint). It is usually a lengthwise or longitudinal tear.

Normally, the posterior horn of the medial meniscus is a difficult structure to see even with an arthroscope. Tight joints with little laxity keep this portion of the meniscus out of sight. But with ligamentous laxity (such as occurs when the anterior cruciate ligament is torn) makes it possible not only to see this portion of the medial meniscus, but also to check it for tears or ramp lesions.

Tears of the medical meniscus are common with ACL injuries. A ramp lesion is a special type of medial meniscus tear that hasn’t been studied as much as other types of meniscal tears.

It occurs most likely as a result of increased torsional (twisting) and shear forces of the tibia (lower leg bone) as it moves against the femur (thigh bone). Anytime the ACL is torn or stretched too much, the tibia can slip and slide more than it should underneath the femur. That’s when the back edge of the meniscus is most likely to crack, tear, and/or pull away from the bone.

In this study, 868 patients with ACL injuries were examined arthroscopically for ramp lesions. Sixteen per cent (actually 16.6 per cent) of the patients had a ramp lesion. And from the data collected, it looks like the longer the ACL injury goes untended, the more likely it is that a ramp lesion will develop. At least that was true up to 24 months after the injury. Beyond two years, the number of ramp tears that developed later leveled off.

Two additional risk factors for ramp lesions were identified: age (younger than 30) and sex (male). Three-fourths of the group only had one ramp lesion (no other tears in the meniscus). But the remaining one-fourth had a ramp tear plus one other meniscal tear — either of the same meniscus or of the lateral meniscus.

The authors describe the three steps they used to inspect the knee for ramp lesions. This was all done with an arthroscope, a special surgical tool used to look inside joints. Needle size, location of the portals (places where the needles are inserted into the joint), and position of the knee to look at the back half of the medical meniscus are described. Photographs taken during arthroscopic examinations of normal knee are presented with photos of ramp lesions for comparison.

In conclusion, ramp lesions affect the knee with a damaged anterior cruciate ligament (ACL) or chronic joint laxity from ACL deficiency. MRIs and routine arthroscopic examinations of the joint don’t always show ramp lesions.

Surgeons must be persistent in looking for this particular type of damage to the medial meniscus. Younger, more active males and patients with chronic (long-term) ACL injuries are at greatest risk for ramp lesions.

Repair of ramp lesions at the time of the ACL reconstruction may be needed but these lesions may heal on their own. Larger tears are more likely to require surgical repair to heal fully. Smaller or nondisplaced (stable) tears can heal without repair. Further studies are needed to confirm these finding before firm recommendations can be made.

Athletes of all kinds can develop pain along the back of the thigh from a hamstring injury. But in this report, seven athletes with posterior thigh pain from an unusual hamstring injury tear are featured.

The hamstring muscle is divided into four parts: the semimembranosus, semitendinosis, biceps femoris, and gracilis. It is the isolated gracilis muscle injury that makes these seven athletes unusual. Posterior thigh strains affecting the biceps femoris are much more common. In fact, this is the first known report published on the topic of isolated gracilis muscle tears.

There wasn’t just one sport that was associated with these injuries. Dancers, soccer players, tennis players, and even a tae kwon do enthusiast were injured. The mechanism of injury (how it happened) was similar for all seven.

Pulling the leg in toward the body (a movement called adduction) combined with full hip flexion and internal (inward) rotation was what did it. The knee of the injured leg was straight. Picture a ballet dancer doing a split with one leg bent. High speed moves like this apply enough tension to the muscle that it can no longer resist the force. The result is a tear at the muscle-tendon junction.

Symptoms of an isolated gracilis muscle tear were similar for all seven athletes. There was an initial sharp pain at the time of the movement that caused the tear. This was followed by uncomfortable pain that got worse over time. Six of the seven athletes developed a lump along the back of the thigh. This lump is where the torn tendon retracted (pulled back) toward the belly of the muscle.

The diagnosis was confirmed with ultrasound imaging that clearly showed the lesion. All seven athletes had a partial tear, labeled as a grade 2 injury.

How did things turn out for these athletes? Everyone recovered fully within six weeks with conservative (nonoperative) care. Full motion, strength, and function were reported by everyone. A recheck 12 months later revealed no further injuries (or reinjuries) of the hamstring muscle.

Could these injuries have been avoided? Can athletes prevent isolated gracilis muscle tears? These are important questions to have answered if you happen to be an athlete in training or someone helping with the training.

The answer may be found by determining why these particular athletes sustained this injury. Because the movements they made that caused the tear are commonly performed by many athletes not just dancers, soccer players, tennis players, and martial artists.

The key may be in the anatomy of the muscle — something the athlete was born with. Of the four hamstring muscles, the gracilis is the thinnest. It is sandwiched between two other muscles, which may help protect it in most people.

It is described as a striplike muscle. It’s a long muscle that crosses two joints (the hip and the knee), which can put it at a mechanical disadvantage. The tendon portion is also long: reaching up from its attachment at the knee half the distance to the hip.

Perhaps there is a difference in the shape, length, or tension in this muscle that puts some athletes at increased risk for injury. Or there may be something about the way it is positioned between the hamstrings and the hip adductors (muscles that move the leg toward the body) that make it vulnerable to tears with this movement. This study was not designed to look for those answers.

For now, it is clear that isolated gracilis hamstring muscle tears do occur. They can be very painful but recover within six weeks’ time. Most athletes can continue to train during the recovery phase with some modifications in their training routine. Reinjury is not common.

Every health care provider must review, study, and keep up with problems presented by patients in their practice. Orthopedic surgeons are no different in this regard. In fact, today’s advanced technology has expanded our understanding and knowledge of all aspects of orthopedic conditions.

In this review, the medial collateral ligament (MCL) of the knee is spotlighted. Anatomy, biomechanics, injuries, examination, and diagnostic classification are featured. Treatment (both surgical and nonsurgical) is discussed with an explanation of the basic science behind treatment decisions.

Some patients present with an isolated medial collateral ligament (MCL) injury. But most MCL injuries are part of a more complex (combined) injury that includes other soft tissues. It’s those combination injuries that are more likely to leave the patient with an unstable joint that requires surgery.

Let’s back track a little and see what the authors had to say about the anatomy and biomechanics of the medial collateral ligament. The name medial tells us the ligament is on the side of the knee closest to the other knee.

This ligament has both parallel and diagonal fibers that run between the tibia (lower leg bone) and the femur (upper leg bone). The dual directional fibers are necessary to provide stability and restraint to the knee joint.

The anatomy is fairly complex as the fibers are interwoven in superficial and deep layers with the fascia (connective tissue). In the same way, the MCL interconnects with other nearby soft tissue structures along the medial side of the knee. In addition, the hamstring muscle, which wraps around the knee from the back of the thigh adds dynamic support to the medical collateral ligament (MCL).

It’s this ligament (with all its supportive structures) that keeps the knee from rotating too much or sliding forward and back. The MCL aids and assists other ligaments inside the joint (e.g., the anterior cruciate ligament or ACL) with this function. This is especially important when force, load, or pressure is applied along the lateral (outside) of the knee toward the medial side.

Understanding the anatomy helps us see how a direct blow to the lateral side of the thigh or leg can disrupt the medial collateral ligament (MCL). Football and rugby players are at risk for this type of injury.

A second mechanism of injury occurs in skiers, basketball players, and soccer players. They plant the foot on the ground and rotate the leg above the foot when pivoting, cutting, or changing directions quickly. The force of that movement pattern can overpower the strength of this ligament. A strong enough force takes out the medial collateral ligament (MCL) along with the meniscus, the anterior cruciate ligament, and other bits and pieces of the soft tissues.

Such complex injuries often lead to knee joint instability and do not respond to conservative (nonoperative) care. Ultrasound and MRI help the surgeon see the location, size, and extent of the injury when classifying the injury as a grade I (strained but intact ligament), II (partially torn ligament), or III (complete) tear.

A key feature of the medial collateral ligament (MCL) that directs treatment is the fact that it is one of the few ligaments that can heal itself. It is located outside of the joint so with the right kind of management, grade I, most grade II, and some grade III injuries can be remodeled and restored enough to support load placed on the knee.

No matter how serious the injury, early treatment consists of immobilization in a splint or brace for a short time (24 hours up to three days). Ice, elevation, compression, antiinflammatory medications, and low intensity ultrasound make up the bulk of conservative care. Exercise to restore motion and strength are prescribed by the physical therapist.

Surgery is saved for those patients who continue to have pain and instability after conservative rehabilitation. When the ligament is torn so badly it cannot reattach to the bone, instability and risk of reinjury make surgery a necessity.

Depending on how many and how much of the other soft tissues are involved, surgery may be a simple direct repair of the torn ligament versus complex reconstruction. The authors guide surgeons through the decision-making process and multiple variables considered when planning the optimal surgical approach. It may be necessary to use graft tissue in order to recreate normal knee function.

One of the other updates on medial collateral injuries presented in this review article has to do with the concepts of prehab (rehab before surgery) as well as post-operative rehab. During prehab, the physical therapist works with patients to restore knee motion as the soft tissues heal. Surgery is scheduled for six to eight weeks after this program is completed.

Recent changes have done away with the old approach of casting the leg for four to eight weeks after surgery. Now the healing ligament is protected with a hinge-brace that allows movement but keeps weight off the joint. This type of brace also protects the recovering ligament from the pulling force of hamstring contractions.

That pretty much covers the basic science of medical collateral ligament (MCL) anatomy, mechanism of injury, and decisions about treatment. In the next update, a different portion of the knee joint (posteromedial corner and MCL plus posterior cruciate ligament injuries) will be highlighted.

Knee arthritis affecting only one side of the joint is a common problem. It occurs as a result of uneven load and weight-bearing on the joint. This type of unicompartmental arthritis is the result of malalignment somewhere in the leg.

There could be a tendency toward a flat foot on that side putting the knee at an angle that increases pressure on the medial side of the joint (closest to the other knee). The angle of the knee itself is sometimes toward a knock-knee position creating the same type of medial load on the joint.

Or there could be a change at the hip that alters knee joint alignment. Any anatomic change that contributes to uneven wear and tear on the joint can result in osteoarthritic damage to the joint lining (called the articular cartilage. Pain from this unicompartmental osteoarthritis can be very limiting.

Treatment choices depend on the age of the patient, activity level, intensity of the painful symptoms, and severity of the joint damage. One possibility is a procedure called an osteotomy.

The surgeon cuts through the proximal tibia (upper part of the lower leg bone) and makes a wedge- or pie-shaped opening. Bone graft material is used to hold the wedge open until the patient’s own bone fills in the gap. A metal plate holds the two edges of the bone in place until complete fusion takes place.

An osteotomy of this type realigns the angle made between the bones of the leg. It can shift your body weight so that the healthy side of the knee joint takes more of the stress. This procedure evens out the weight from one side of the joint to the other side and takes some of the load and pressure off the damaged side.

But how well does it work for unicompartmental osteoarthritis? The idea of reducing load on the injured side in order to preserve the tissue still left or to regenerate new cartilage isn’t new.

Previous studies have been able to show that the body does form fibrous cartilage on the damaged joint surface. But it’s not exactly the same as the original tissue, so the next question is: how well does it hold up under load and pressure? In other words, how functional is this treatment approach?

Special MRIs with dye that seeps into the cartilage and first layer of bone were used to examine the knee joints of 10 patients (eight men and two women). They all had a medial opening wedge high tibial osteotomy (HTO). Baseline images were taken before surgery. Images were repeated after surgery at six months, 12 months, and 24 months. Other test measures of knee function were also recorded (using the Knee Injury and Osteoarthritis Outcome Score or KOOS).

The results showed that patients were able to generate some articular cartilage but not back to a normal amount. The lateral side of the knee still had more normal (and thicker) articular cartilage than the medial side. Changes were visible at the six month check-up. Improvements continued to be seen at the 12 month and 24 month follow-up appointments. Knee function was also significantly improved.

It’s possible that continued changes occurred after the 24 month mark. Further study will be done to see if the joint cartilage reaches a level close to normal. Patients in this study were kept nonweight-bearing for three months after surgery.

It wasn’t until they started walking on the leg that measurable changes in the cartilage were observed. Exactly at what point between three and six months the changes started developing remains unknown and a topic for future study. The study was also fairly small (10 patients) so it will be necessary to repeat the study with a larger number of people.

For now, it appears there is a trend toward cartilage regeneration and recovery using a tibial osteotomy treatment approach for painful unilateral knee joint osteoarthritis. Improving joint dynamics and evening out the biomechanical load on the joint is possible with this surgical approach.

The current trend in medicine is to study each medical condition looking for evidence to support specific treatments as being the best way to approach a problem. One of the best ways to develop specific evidence-based treatment programs is to look back on patient outcomes after treatment and see what kind of results were obtained. Then a treatment algorithm (step-by-step process) can be developed.

In this article, a treatment algorithm for primary (first time) patellar (knee cap) dislocation is presented. The process begins with the physician taking a patient history and performing a physical exam.

The history includes questions about how, when, and why the injury happened. It’s important to find out if the patient ever had a similar injury in the past (for either knee). A previous history of knee dislocation is a red flag for recurrent (repeated) patellar dislocations.

Clinical tests performed by the physician must confirm that a patellar dislocation occurred. Just as important, the examiner checks for any injuries or damage to other areas of the knee (e.g., ligaments, cartilage, connective tissue, bone).

In particular, knee dislocations with a piece of bone displaced may require a different treatment approach. This type of injury is referred to as an osteochondral fragment or fracture.

X-rays may not show evidence of bone damage. MRIs are more accurate in outlining the surface of the joint. Any disruptions that might suggest damage to the cartilage or bone with a free-floating fragment inside the patellar joint will be seen with MRIs.

The size and location of the fragment are important factors to evaluate when planning surgery. Small pieces or fragments may not have to be repaired or removed. Larger bone fragments may be reattached to restore and preserve the injured site.

The big question is always about treatment. Can primary patellar dislocations be managed conservatively (i.e., without surgery)? How do you know if surgery is needed? And what type of surgical procedure should be done? Looking back over studies done in this area, here’s what the authors of this evidence-based review found: