FAQ Category: Knee

No one knows for sure what causes patellofemoral pain syndrome (PFPS). It’s likely that the problem is multifactorial — in other words, it has many factors. Some experts think that when enough contributing factors are present, the problem develops.

There could be some anatomical changes, overuse and repetitive motions, and even muscle atrophy (wasting) that when added together kick in this problem. In fact, a recent study from Belgium has just added some new information to help us better understand PFPS.

They used MRIs to measure the size of the vastus medialis obliquus (VMO) in two groups of people. The VMO is one part of the quadriceps muscle along the front of the thigh. It is the section of muscle closest to the other knee.

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 of that study we mentioned also suggest looking at muscle strength as it relates to the size of the VMO in different people.

Not necessarily though all the data from long-term studies isn’t in yet. What we do know is that meniscal repair (rather than removal) is done whenever possible. The important role of the meniscus in sharing the joint load and as a shock absorber and knee stabilizer has been well-documented.

Having some understanding of the healing rates and long-term results of surgery for this age group has helped surgeons advise and counsel young patients. The location, type, and extent of meniscal injury is important even for younger athletes.

To their advantage is the fact that the quality of the cartilage before injury is usually very good and they have more of a blood supply to that area than adults typically do. Both of those factors aid in a faster recovery during the healing process.

Meniscal tears in teens is on the rise with more and more sports participation. Even so, long-term data (10 to 20 years after injury and treatment) are not available yet. Short-term results are very favorable after arthroscopic repair. Eighty (80) per cent are symptom-free with no signs of joint degeneration seen on X-rays.

Most athletes return to their preinjury level of play within six months’ time. Continuation of sports participation may be an additional factor in the final results (i.e., what happens to the knee over time) but future studies are needed to follow this more closely before we will know for sure.

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.

Patients have wondered if they aren’t putting themselves at increased risk for complications with this new approach. But surgeons have persisted in trying to perfect this technique because the computer makes more accurate bone cuts and positions the implant more precisely.

The results of at least one study have confirmed that although the computer-assisted procedure takes about 30 minutes longer than the conventional approach, there was no increase in complications reported.

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.

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).

We don’t know the long-term results of knee replacements aided by computers. But for now we can say the computer-navigated technique provides a more accurate alignment for total knee replacements without increased problems or complications. And for some patients, that might be enough incentive to chase down a surgeon who is already using this approach!

There are several different companies around the world that offer navigational-assistant surgical systems. U.S.-based companies are among them making it possible for surgeons and patients to benefit from this approach since the early 21st century (2000-2001).

For example, orthopedic surgeons are training on the new computer-assisted navigational system with hopes of improving alignment of implants for joint replacements. Combining the computer-assisted navigation with minimally invasive surgical techniques (MIS) may forever change the way joint replacements are being done. Some experts suggest that most orthopedic procedures will be computer assisted in the next five-to-10 year period of time.

These new methods are no longer experimental but they are considered investigational (data is still being collected and analyzed to see results). It is hoped that with improved visual access to the joint, more precise implantation will be possible, and thus patient outcomes will continue to improve.

Recently, a panel of 50 experts in the field of platelet-rich plasma (PRP) treatment (also known as blood injection therapy got together to compare notes on what this treatment works for and what it doesn’t help with.

They made the following key observations:

For those readers who don’t know, a unicompartmental knee replacement (also known as a unicondylar knee replacement) is designed to replace only the portions of the joint that are most damaged by arthritis. This approach is less invasive than a full knee replacement.

Usually the medial side of the joint is removed and replace. The medial joint is the side closest to the other knee. But sometimes it is the lateral (side away from the other knee) that needs replacing.

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.

It doesn’t happen very often but sometimes there is a patient with a unicompartmental knee replacement that has failed. Removal and replacement with a total knee replacement becomes necessary.

Often before going to that extreme, the surgeon will recommend conservative care for pain management, postural alignment, gait training, strengthening, and anything else that might help the patient live well with the implant and overcome the disability. If you have not worked with a physical therapist for at least three months to overcome your current symptoms, then such a move might be the place to start.

Talk to your surgeon about what he or she would suggest for you. Ask what your options are and if conversion to a total knee replacement might work for you.

We are assuming by half-knee replacement, you are referring to a unicompartmental implant. 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.

But problems can develop. Conversion from a unicompartmental implant to a total replacement 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.

There are ways for the surgeon to avoid these problems during conversion. Some surgeons leave 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 surgeon tries to avoid making the two ends of the femur (thigh bone) even with each other. Instead, bone graft can be used to lengthen the unicompartmental side if it is too short. 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.

Bone on the tibial side (upper end of the lower leg bone) is measured and removed next. Again, the surgeon tries to cut as little bone away as possible. 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.

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.

Any surgery can result in infection, blood clots, or other complications. These are rare but they do happen. Ask your surgeon to go over the procedure with you and outline any problems that could arise. That will give you a chance to ask any other questions you may have.

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 patients involved, patient compliance (cooperation), type of neuromuscular electrical stimulation applied, and intensity of the stimulation.

According to one study from the Center for Knee and Foot Surgery Sports Traumatology Center in Heidelberg, Germany, rehab results can be speeded up after knee surgery by using an electrical impulse to aid the muscle contraction.

In this particular study, electrical current to the quadriceps muscle was applied after anterior cruciate ligament (ACL) reconstructive surgery. 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 provided 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).

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

The Kneehab device is a wrap around sleeve that fits over the quadriceps muscle and provides electrical stimulation to help improve muscle contraction. The patient contracts the muscle as much as possible while the unit cycles on. Then the patient (and machine) relax the muscle during the off cycle. The goal is to improve muscle strength and function after surgery.

Does it work? Research results are trickling in but so far it looks favorable. The Kneehab unit has three advantages over other types of neuromuscular electrical stimulation (NMES) units.

First, it is easy to slip on and off. The ease of application makes consistent patient compliance (i.e., use as prescribed) more likely. And third, the electrodes built into the device are larger than standard electrodes. This feature is said to provide greater muscle activation.

Studies of neuromuscular electrical stimulation (NMES) have shown that adding NMES to patient voluntary muscle contraction does make a difference. One study comparing the Kneehab unit to a standard polystim unit did show faster, better results using the Kneehab after anterior cruciate ligament surgery.

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).

Claims that it can be used to help avoid or delay surgery must be investigated further. Other research ideas have been proposed using the Kneehab neuromuscular electrical stimulation. One is with other types of knee surgery such as knee replacements and another using neuromuscular electrical stimulation combined with a rehab program before knee surgery.

Soft tissue structures around the knee are very complex. They are woven together and work to help one another stabilize, support, and move the joint. 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.

Some injuries are more obvious than others. For example, clinical tests performed by the physician are usually pretty clear if either one of the two main ligaments that criss-cross inside the joint are injured (posterior cruciate ligament or anterior cruciate ligament).

Damage to the corners can be much more difficult to diagnose. You might not realize it, but the knee actually has “corners.” There are two corners in the front (anterior) and two in the back (posterior.

Then add one a direction from each side: medial (side closest to the other knee) and lateral (side away from the other knee). Combining front and side and back and side gives us corners named anteromedial, anterolateral, posteromedial, and posterolateral.

Each “corner” is made up of the ligaments, meniscus (knee cartilage), tendons, and connective tissue that converge at that point. For example, the posteromedial corner (PMC) of the knee contains the posterior oblique ligament (POL), part of the hamstring muscle/tendon, the oblique popliteal ligament (OPL), and the back curved corner of the meniscus.

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 can be difficult. Even with all or our imaging technology, the exact nature and extent of soft tissue and/or bone injury just isn’t clear. There can be subtle bone bruising, tiny bone fractures, or a pulling away of the meniscus from the edge of the bone.

Sometimes, it isn’t until the patient has gone through rehab and even a first surgery before the unrecognized damage becomes obvious enough to diagnose and treat. The delay isn’t always a disadvantage.

Some tissues heal on their own with enough time on their side. And in some cases, further testing is required to get to the bottom of the problem. That may take some time and patience.

The MCL or medial collateral ligament is located in the knee on the side closest to the other knee. It helps stabilize the knee joint and prevent injury when force is directed through that side of the knee. An isolated injury to this ligament could very well heal with rest and activity modification.

Not all ligaments have a good blood supply in order to create a healing response. But the MCL does have more of a healing capacity than most ligaments. If there are no other injuries to the meniscus, cruciate ligaments, or other soft tissues, you may expect a good recovery from this type of injury.

If the knee is stable (not giving out from under you), then a brace isn’t usually needed. And since you have seen a physician, it sounds like your knee was examined before making the recommendations to give it some time.

With a history of injury and reinjury, if you experience further problems, don’t wait to get back in to see the physician for a follow-up visit. A supportive splint and exercises may be advised at that point.

Surgery is rarely done for an acutely injured MCL unless it is part of an injury that has damaged multiple knee ligaments and/or soft tissues. When joint laxity threatens the integrity of the joint, then surgery to repair or reconstruct the soft tissues (including the MCL) may be necessary.

What you are seeing is a special strap designed to reduce knee pain in athletes who run and jump frequently causing microtrauma to the patellar tendon. The straps are a form of patellar orthotics (bracing) called infrapatellar straps or bands. The different colors represent different brands sold by different companies.

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 have observed, the straps are worn most often by 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 experiencing pain from a patellar tendon problem.

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. The general effect is to reduce strain on the tendon and thereby reduce pain.

The knee straps you are referring to 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. But they can be used by anyone with pain associated with patellar tendinopathy.

Tendinopathy refers to any tendon that has been damaged in some way but is no longer in the acute inflammatory phase (which would be called a tendinitis). Examination of tendon tissue in patients who have had chronic pain over months and sometimes even years showed scarring and fibrosis but no active fluid, swelling, or white blood cells at the site needed for healing.

There aren’t very many high-quality studies published showing the results of using this strap for knee pain. One recent publication from Michigan State University was based on healthy men who did not have knee pain. Two different brands of these infrapatellar straps were used and compared.

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.

As we mentioned, the study 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. The use of these straps to prevent patellar-tendon problems must be investigated. Likewise, the effectiveness of the straps for other kinds of knee problems should be studied.

Before using the strap, you may want to see an orthopedic surgeon and get a proper diagnosis for your knee pain. Knowing the exact cause and mechanism of knee pain is usually prescriptive — in other words, this information directs treatment based on what we know is most successful for each individual diagnosis.

Housemaid’s knee is a term sometimes still used to describe bursitis. Bursitis is the inflammation of a bursa. A bursa is a sac made of thin, slippery tissue. Bursae (plural) occur in the body wherever skin, muscles, or tendons need to slide over bone.

Bursae are lubricated with a small amount of fluid inside that helps reduce friction from the sliding parts. They can also be found between muscle and fibrous bands of connective tissue. Four of the most common areas where bursitis develop are the knee, elbow, hip, and heel. Causes of bursitis include trauma, inflammation, and infection.

Treatment depends on the underlying etiology (cause) of the problem. The diagnosis is made based on patient history, symptoms, and special tests. The problem must always be sorted out carefully as the same symptoms can occur with tumors, arthritis, fractures, tendinitis, and nerve damage. Sometimes bursitis is a secondary problem caused by some other disease process such as gout or sarcoidosis.

Treatment is usually conservative (nonoperative) care. Rest, activity modification, and medications such as antiinflammatories (for pain and swelling) or antibiotics (for infection) are the main management tools. Stretching the soft tissues around the bursa may help. Applying a compressive wrap or garment around the knee may give some relief from the painful symptoms but may not eliminate the problem.

Surgery to remove the bursa (called bursectomy) is usually reserved for patients who do not respond to nonsurgical care. There is always a risk of additional problems or complications with any surgery, so this is not the first step in treatment. But it has its place when all else fails.

In your case (kneeling and/or crawling on the floor), a knee pad may be helpful as well. Something as simple as the type of protective pads carpet layers wear may be all you need. Try it out and see how it feels. Something with memory foam or compressed foam will offer the best support. Limiting your floor activities may be required until you get the symptoms under control.

The three factors you mentioned (smoking, alcohol use, and diet) are important considerations. 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 likely is it that your father would develop an infection after surgery? Studies report the risk of periprosthetic infection is anywhere between 0.4 and two per cent for adults receiving a knee replacement. The upper 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.

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. The distinction between periprosthetic and wound infection is made here by just mentioning periprosthetic infections. Infection around the incision and soft tissues is a separate issue.

The surgeon would not perform a total knee replacement procedure if your father wasn’t a good candidate. But as with all surgeries, patients must be warned of potential risk factors, complications, and problems that can arise. Your concern for your father is important. If possible, go with your father to a pre-op appointment and ask questions to help you gain a better understanding of the perceived versus real concerns and risks.

Surgeons do everything they can to prevent and avoid infections of any kind after surgery. With joint replacement, there can be skin, wound (or other soft tissue), bone, and periprosthetic (around the implant) infections.

How does a patient know if his or her knee (joint) 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. Risk factors include smoking, alcohol abuse, and obesity> A history of diabetes, cancer, chemotherapy, rheumatoid arthritis, or blood clotting disorders add to the risk.

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.

If you think something unusual is going on, it’s best to get in to see your surgeon right away. Early diagnosis and treatment can help reduce the severity of problems and restore the natural healing process. If nothing else, at least call your surgeon’s office and let the staff know of your concerns and suspicions. They will direct you from there!

Reinjury after an anterior cruciate ligament (ACL) injury is always a niggling concern in the back of the mind of most people. This is especially true for athletes who are putting the knee to the test with their activities.

The actual incidence of reinjury varies depending on age, level and type of activity, and treatment approach (conservative or nonoperative versus surgery). But studies show that improvements in surgical technique and post-operative rehab programs has made a difference in improving outcomes. With the development of tendon grafts and better fixation methods, a faster, more aggressive rehab program is possible.

But predicting who will have a second injury (or even a first injury on the opposite side) can be much more difficult. Prevention is less likely without an understanding of what are the predictive risk factors.

A recent study may offer some help in this area. 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.

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.

Being able to successfully hop on one leg shows that 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.

Equalizing strength from side-to-side may not be the only way to prevent future injuries but it at least gives us a place to start. Future studies are needed to provide other predictive factors and insights for injury prevention.

From what you just told us, it sounds like you have completed a full rehab program under the supervision of a sports physical therapist. Have you been tested to know that you have the strength, flexibility, and motion needed for the kinds of sports activities required on the basketball court?

Most competitive sports training activities are two-legged (broad jump, vertical jump, shuttle run). And those are important. But it is equally important that you include some unilateral (single-leg) hopping as well. Types of unilateral hopping include hopping forward on one leg as far as possible and landing safely on the same leg each time.

A second type of hopping activity is the crossover hop. You’ll need a straight line of some sort for this one. While hopping on one foot, first you hop on one side of the line, then you cross over the line and land on the opposite side.

Keep hopping forward switching sides of the line that you land on. It’s important to “stick” the landing (as gymnasts would say). In other words, hop and then land without wobbling or losing your balance. Hopping smoothly from side to side for the full distance is a measure of strength, power, and agility. Single-leg hopping skills are a good measure of readiness to return to full participation on the court.

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. Efforts should be made to equalize performance from side-to-side as a way to prevent future problems (including injury of the uninvolved knee).

Athletes of all kinds can develop pain along the back of the thigh from a hamstring injury. The hamstring muscle is divided into four parts: the semimembranosus, semitendinosis, biceps femoris, and gracilis. Posterior thigh strains affecting the biceps femoris are the most common. Gracilis tears are the least common.

The mechanism of injury (how it happens) is often from pulling the leg in toward the body (a movement called adduction) combined with full hip flexion and internal (inward) rotation. The knee of the injured leg is straight.

A gymnast or ballet dancer doing a split with one leg bent (like the spagat — split out to the side) could cause such an injury. 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.

The key to this injury may be in the anatomy of the muscle — something you were 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.

Further studies are needed to take a closer look at the cause of this injury. Why some people performing this move aren’t injured while others are is a mystery. Likewise, why you could do the spagat 100s of times just fine and then tear the muscle on the 101st attempt is also unknown.

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.

The gracilis muscle is part of the hamstrings along the back of the thigh. The hamstring muscle is divided into four parts: the semimembranosus, semitendinosis, biceps femoris, and gracilis.

Isolated gracilis hamstring tears are uncommon. Posterior thigh strains affecting the biceps femoris are much more common. To help answer your questions, we found a recent report on seven athletes with an injury of this type.

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.

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. These athletes did continue to train during the recovery phase with some modifications in their training routine.