News Category: Knee

With today’s improved technology in and out of the operating room, patients have the option of bilateral total knee replacement (TKR) at the same time. This can be done by one surgical team doing both knees (first one, then the other) in the same operation. Or there can be two surgical teams working on both knees at the same time.

Patients who qualify for bilateral simultaneous TKRs have changed over the years. Surgeons still agree that patients older than 80 years of age should not have both knees done at the same time. The risk of serious complications is just too high in this group. The biggest change in patient selection is that older, sicker adults are approved for this procedure.

In this article, surgeons review the major complications, pros, and cons of having both knees replaced at the same time. They start out by saying there isn’t one most common adverse event reported in the literature.

Cardiac, pulmonary, and neurologic complications are compared. The most serious complication (death) is not any more likely after this procedure than in people of the same age dying of natural causes. Other problems that can occur include blood clots, the need for blood transfusion, and electrolyte imbalances. Gastrointestinal problems have also been reported.

The overall rate of complications is greater for bilateral TKR compared with unilateral or staged bilateral procedures. Staged bilateral refers to having both knees replaced but they are done one at a time with a certain time interval (weeks to months) between procedures. The number of patients sent to the intensive care unit (ICU) is higher with simultaneous TKRs. The number of days they stay in ICU is also greater for bilateral versus unilateral TKR.

Cardiac complications range from angina (chest pain) to heart attack, unstable heart rhythm, and heart failure. Heart attacks and heart arrhythmias top the list of most commonly reported cardiac problems.

The risk of cardiac complications in patients having bilateral TKRs is four times the risk for those having one knee done. This is one reason why patients over 80 aren’t encouraged to have bilateral TKRs. The risk of heart problems increases with age. There are several reasons for this. Heart disease is more common as we age. And the heart and lungs have less reserve capacity to respond to the stress of surgery.

The most common pulmonary complications after bilateral simultaneous TKR are pulmonary embolism (blood clot) and fat embolism. When the bone is cut open, a glob of fat from inside the bone marrow can enter the blood stream. The embolism travels to the heart or brain causing serious problems such as death, heart attack, or stroke. Improved surgical techniques are helping to reduce the number of fat emboli that cause postoperative problems.

Confusion or increased confusion is the main sign of neurologic complications after TKR. This may be linked with fat embolism or the stress of the surgery. Electrolyte imbalances, dehydration, and low red blood cells all contribute to the presence of confusion. Older adults seem particularly susceptible to confusion after bilateral simultaneous TKRs.

On the plus side, there is less anesthesia used with bilateral simultaneous TKRs. Improved surgical technique means less blood loss. And rehab has to be done for both knees anyway. So the total length of time in recovery is less. There are fewer days of pain and a shorter hospital stay with fewer costs.

When making the decision to replace both knees at the same time, the surgeon must consider many factors. Besides the patient’s risk factors, the presence of any other medical problems or conditions must be factored into the equation. Hospital staffing of nurses, operating room tech support, and experience of surgeon and staff are all important points.

It has been suggested by many researchers based on results of studies that bilateral knee replacements are best done in high-volume hospitals by an experienced surgeon. Usually such facilities also have adequate intensive care units to care for patients who need close monitoring.

Many other areas of concern for patient safety have been raised. For example, what is the recommended age for patients to have the bilateral procedure? Can the relative risk be determined in order to avoid depriving patients of this bilateral procedure?

What is the true cause of all these complications? How important is the health status of each patient before surgery to the postoperative outcomes? And finally, if the procedure is staged, what’s the optimal amount of time between the two procedures? Perhaps it is possible to decrease the risk of complications with a specific time interval.

Hopefully, in time, more studies with larger numbers of patients will be published to determine best practice for simultaneous bilateral TKRs. Until then, each patient is treated individually. Decisions are made on a case by case basis using all current information available.

We are one step closer to solving the problem of anterior cruciate ligament injuries among female athletes. Improving neuromuscular control with a specific exercise program three times per week may be the answer.

In this study, women’s college soccer teams were divided into exercise versus control groups. The control group did their own warm-up routines, practiced, and played as usual without any special exercise intervention.

The exercise group did a special warm-up program before practice three times each week. Stretching, strengthening, agility drills, and plyometrics were included. The exercise group was also shown how to avoid positions that put the knee at risk for ACL injury.

Plyometrics is a training program that loads and contracts the muscles maximally and quickly. The muscle generates as strong a contraction as possible in the shortest amount of time. Fast, powerful movements improve the speed of the nervous system function and enhance sports performance.

This particular exercise program was first developed by the Santa Monica Orthopedic and Sports Medicine Research Foundation. They called it the Prevent Injury and Enhance Performance (PEP) Program. The program consists of 19 parts that can be done by the whole team in less than 30 minutes. It was studied and found to be successful in the late 1990s. This study is a continuation of the work that was done at that time.

National Collegiate Athletic Association (NCAA) Division I soccer teams from around the country were included. There were 61 teams with over 1400 athletes involved. The goal was to see if this alternative warm-up program could reduce the number of ACL injuries. The specific focus was on noncontact injuries among female athletes.

The exercise groups used the PEP program for 12 weeks during the regular soccer season. The teams had to complete the PEP program at least 12 times to be included in the data analysis. Most teams reported completing an average of 25 exercise sessions.

Knee injuries requiring medical care and causing missed days of practice or play were counted for all participants in both the exercise and the control groups. The most common knee injury in both groups was a medial collateral ligament injury. Rates of MCL injury were equal between the two groups.

New ACL injuries and repeat injuries were less in the exercise group. Only injuries confirmed by MRIs or arthroscopy were considered true ACL injuries. This was especially noticeable among noncontact injuries and included both practices and games. Noncontact refers to the fact that the athlete did not collide with another player or object. The injury occurs most often when landing from a jump or when the foot is planted on the ground and the athlete is doing a cutting (side-step) motion.

The authors note that injuries continued to be reduced in the exercise group late into the season. They suspect this is the result of the benefits of the training as strength, balance, and joint proprioception (sense of position) improve. And although the program was designed for soccer players, it’s possible it could be modified to use with basketball or volleyball players.

In summary, the PEP program is safe and effective in reducing the number of all ACL injuries in female soccer players. The program can be carried out easily during the regular practice time. No special equipment is needed.

A training video can be used to demonstrate all the exercises. This type of neuromuscular program takes several weeks to improve strength, balance, and proprioception. Athletes reported the program got easier as time went by. After six to 12 training sessions, the exercises were no longer perceived as physically challenging.

Bipartite patella is a congenital condition (present at birth) that occurs when the patella (kneecap) is made of two bones (instead of a single bone). Normally, the two bones would fuse together as the child grows. But in patella bipartite, they remain as two separate bones.

Most of the time, this condition is silent. The person doesn’t even know he or she has it. But direct trauma to the kneecap or repetitive injury (overuse) can trigger painful symptoms. In this article, orthopedic surgeons from Canada review the classification, clinical features, and diagnosis of bipartite patella. They offer treatment alternatives for symptomatic cases.

Bipartite patella can be classified or labeled according to the location of the bone fragments. This is determined using imaging studies such as X-rays, MRIs, and scintigraphy (bone scans). In Type I, the extra bone is at the bottom of the patella. This area is referred to as the inferior pole.

Type II tells us the fragment is along the lateral edge. Lateral refers to the side of the patella away from the other knee. And a Type III bipartite patella has a fragment at the upper-outer corner of the patella. This area is called the superolateral pole.

Treatment is usually nonoperative at first. Rest, activity modification, and sports restriction are advised. Anti-inflammatory medication is usually prescribed. Physical therapy is started to stretch and strengthen the muscles surrounding the knee.

Severe pain may require immobilization and/or steroid injections. Putting the knee in a brace with limited knee extension prevents contraction of the quadriceps muscle. The result is to decrease a traction force on the fragment.

In most cases, conservative care is carried out for at least six months before considering surgery. There are some exceptions. For example, immediate surgery may be needed in cases of direct trauma or when the pain prevents daily activities. When surgery is recommended, there are several possible methods to choose from.

The first is an open incision and removal of the bone fragment. There are many studies using this method and reporting good-to-excellent responses. The procedure is invasive. The surgeon cuts down to the quadriceps tendon. Removing a large fragment this way can cause problems later with the patellofemoral joint. This is where the patella moves up and down over the femur. The two surfaces no longer match up for smooth tracking.

The second surgical treatment is a lateral retinacular release. The surgeon cuts the connective tissue holding the quadriceps to the outer edge of the kneecap. This releases the traction force put on the patella by the vastus lateralis muscle. The vastus lateralis is the outer most tendon of the four tendons that make up the quadriceps muscle.

In some cases, a lateral release allows the two bone fragments to join together and heal. Pain is relieved within four weeks. Athletes are able to return to their pre-injury level of sports participation. This procedure can be done arthroscopically, thus avoiding an open incision. Studies show that results are improved with this technique. There is less swelling after surgery and faster recovery of muscle strength post-operatively.

A third surgical technique is the subperiosteal detachment of the vastus lateralis insertion. This method accomplishes the same thing as a lateral release but without weakening the vastus lateralis muscle. By just releasing the tendon from the fragment and from under the first layer of bone, the action of the muscle is not altered. The fragment may or may not be removed. This depends on how severe the condition is. In some patients, the fragment can and does join with the rest of the patella.

And finally, there is a more invasive approach, called open reduction and internal fixation (ORIF). An open incision is made. The fragment is attached to the main patella with wires or screws. This procedure is used when the fragment is large and removing it would cause patellofemoral arthritis later.

Many people are familiar with anterior cruciate ligament (ACL) tears. But inside the knee joint there are two important ligaments. The ACL criss-crosses with the posterior cruciate ligament (PCL). And PCL injuries account for up to one-third of all knee injuries.

The PCLs main job is to keep the tibia (lower leg bone) from sliding backwards under the femur (thigh bone). A second function of the PCL is to restrain the tibia from rotating outward too far.

There is a broad range of acceptable treatment methods for PCL injuries. For mild injuries, conservative (nonoperative) care is advised. This may include physical therapy and/or bracing. Reconstructive surgery may be needed. But whereas surgical treatment for ACL injuries is fairly standard now, there isn’t one single method of surgical management for PCL injuries that is considered the gold standard.

In this study, surgeons used cadaver knees (preserved after death for study) to help iron out this problem. They specifically focused in on the effects of injury to the PCL. They also looked at what happens when the posterolateral corner of the knee joint is damaged. Severe PCL tears are often accompanied by damage to this corner of the knee where the femur and tibia meet.

Posterior refers to the back side of the knee.Lateral is along the outside edge of the joint. There are five basic structures that make up the posterolateral corner. These include two muscles: the lateral head of the gastrocnemius (calf) and the popliteus. Three ligaments are also involved: the popliteofibular ligament, the lateral collateral ligament (LCL), and the arcuate-fabellofibular ligament complex.

The researchers placed 10 pairs of intact (normal) cadaver knees in a special limb-holder. The PCL of each knee was tested. Then they cut the PCL and retested the specimens. In the third step, they took out the posterolateral corner (as if it were torn completely) and retested again.

The tests consisted of the posterior drawer test, the dial test, and stress radiography. The posterior drawer test is done by the examiner. The knee is bent 90-degrees. The foot is stabilized (usually flat on the floor or examining table) while the examiner grasps the lower leg and pushes it backward. If the tibia moves back more than normal, the test is positive for a probable PCL tear.

PCL tears were graded as 0 for normal (the tibia moves or gives a little but not easily), Grade 1 for three to five millimeters (mm) of posterior translation (backward movement), Grade 2 for six to 10 mm, and Grade three for more than 10 mm of displacement.

The dial test is done by using a goniometer to measure how far the tibia can rotate externally (outwardly). A goniometer is a special tool used to measure joint range-of-motion. The goniometer measurement was taken with the knee in 30-degrees of flexion and in 90-degrees of flexion.

Stress radiography is a series of X-rays taken with the knee in a neutral position and then in a positive posterior drawer position. In both views, the knee was flexed 90-degrees. A special device was used to apply enough force to the upper portion of the tibia to displace it backwards. The X-rays were repeated after the posterolateral corner was removed.

All data collected was compared among the intact knees, knees with an isolated Grade 2 PCL injury, and knees with damage done to both the PCL and posterolateral corner (Grade 3). With each additional injury, the amount of posterior tibial displacement increased. The amount of external tibia rotation also increased. This was especially noticeable with damage to the posterolateral corner.

The findings were summarized as follows:

Hamstring injuries are common in sprinters. If we can find specific reasons for this, injuries to elite sprinters may be avoided. In this research, the relationship between hip and thigh muscle strength to hamstring injury was studied. The scientists conducting this study looked for imbalances and deficits in muscle strength between the quadriceps and the hamstrings.

They chose 30 men who were elite track and field sprinters. All had participated in athletic championships. One member was even on the 2004 Olympic relay team. Muscle strength was measured using a special tool called a dynamometer.

Eccentric and concentric muscle testing was performed at three speeds (60 degrees per second, 180 degrees per sec, and 300 degrees per second). There was a one-minute rest between each speed.

Eccentric refers to lengthening of the muscle from a shortened position. Concentric is the opposite: the muscle is shortening as it contracts. The muscle testing mimicked the function of the hamstrings during the late swing phase and early contact phase of sprinting.

The athletes were all trained on how to use the dynamometer before testing began. Each athlete had a 10- to 15-minute warm-up period before testing. Knee and hip muscle strength were both measured in the standing position. To avoid injury, the strength testing was not done on the same day for both the knee and the hip motions.

After testing, the athletes were observed for a full year. Number of practices and meets was recorded for each athlete. The occurrence of a hamstring injury sustained during sprinting was also recorded. A hamstring injury was defined as one that caused a break in training or competition for at least a week.

They compared the preseason muscle strengths between the sprinters who had a hamstring injury and those who didn’t. Measurements were compared between the right and left legs for the injured and uninjured groups.

The results showed weakness of the muscles in the injured leg. But the weakness was only present at the slowest speed. The specific muscle contractions affected were concentric for hip extensors and eccentric for knee flexors. Strength ratios between hamstrings and quadriceps muscles were also seen. The authors think the change in hamstring strength accounted for the ratio differences.

The conclusion of this study was that it may be possible to prevent hamstring injuries in elite sprinters. The first step is to test for pre-season muscle strength. Use this information to identify anyone with differences from side to side.

Unilateral weakness of the hamstring muscle as a hip extensor and knee flexor is a red flag. A strength training program to correct the muscle deficit and imbalance may help. There may be other key factors that could make a difference. Further studies are needed to look for other areas that might contribute to hamstring function and injury.

Researchers are actively seeking information and knowledge that can reduce the number of anterior cruciate ligament (ACL) injuries in women. Several studies are ongoing collecting information about hip and knee function and strength in jumping athletes.

And it just so happened that one of those athletes (a basketball player) was in a study when she ruptured her ACL. Approximately 45 minutes after recreational basketball play started, she landed from a jump stop and injured her knee. Just hours before the game, she had been seen by a physical therapist.

The therapist was able to review the athlete’s records from eight months before the ACL injury up to four hours before the injury. Measures available included quadriceps muscle strength and activation, kinetic data on movement, and reaction force generated by drop jump landings.

Quadriceps activation was measured using an electrical stimulus. The minimum amount of electrical impulse needed to cause a contraction of the muscle was recorded. Then the athlete maximally contracted the muscle and the researcher re-measured the force needed to complete the contraction. From these measurements, the researchers could calculate force production of the muscle.

The data showed that force production was decreased four hours before the injury compared with just one week prior to the injury. The same data was collected again shortly after the injury, before surgery, and after surgery. Unfortunately, because of the nature of the injury (ACL rupture), data on the kinetics during a drop jump landing could not be collected after the injury (before surgery).

Surgery was delayed by three months as the athlete completed a rehab program. The program included range-of-motion, pain relief, quadriceps strengthening, and exercises to improve neuromuscular control. Strength and force generated by the quadriceps muscle was improved as shown by measurements taken the day before surgery.

Five months after surgery, these same measurements were repeated. The maximum voluntary muscle contraction was better than before the injury but not quite as good as just before surgery.

Looking back over all the data collected, it appears that this athlete had some risk factors for ACL injury. Her knees were both in a position of valgus (knock-knee position) during her drop jump landings. The left foot (which she injured) was positioned slightly forward of the uninjured foot. And there was a reduced or incomplete activation of the quadriceps muscle.

The authors suspect that muscle fatigue from playing basketball was a significant factor in this injury. According to some studies, quadriceps force output is less after the muscle has been in use. There are fewer motor neurons to fire when contracting the muscle. Decreased muscle activation along with fatigue may be just the right combination of risk factors to result in an ACL injury.

Obviously, a large study of this type isn’t possible. But future studies may be able to compare preseason data as a baseline with number of injuries that occur during season practices and play. A pattern or trend may be identified that could help prescreen athletes for injury risk and begin a prevention program.

The patella, or kneecap, can be a source of knee pain when it fails to function properly. Alignment or overuse problems of the patella can lead to pain, weakness, and swelling of the patellofemoral joint. This problem is called patellofemoral pain syndrome (PFPS). PFPS is most common among athletes, especially teens and young adults.

Many studies have shown exercise works to help PFPS. Other studies have used electrical muscle stimulation (EMS) to help with knee problems such as osteoarthritis, painful sports injuries, and after knee surgery. In this study, physicians from the Medical University of Vienna test to see if EMS might help with PFPS.

All patients included had bilateral knee pain associated with PFPS. They were divided up into two treatment groups. Group one followed an exercise program outlined by a physical therapist. Group two had the same exercises and EMS. Both groups were treated for 12 weeks.

Daily exercises included trunk and leg isometric, concentric, and eccentric strengthening. Functional activities such as stepping, squatting, and balance training were also included as part of the exercise training program.

The therapist progressed each patient’s exercise program according to his or her pain levels. Stretching of the calf and thigh muscles were done at the end of each training session. A special appendix at the end of the article provided detailed information of the daily and weekly progression of the training program.

For group two, EMS electrodes were used to stimulate contraction of the quadriceps muscle. A twice-daily program of 20 minutes self-stimulation was used by the patients at home. The stimulation intensity was kept as high as the patient could comfortably tolerate.

Results were measured at the end of the three months training period. Pain levels, function (Kujala patellofemoral test), and muscle strength were the main outcome measures. Strength was tested using an isometric contraction. A special chair was specifically designed to conduct strength testing in the seated position.

There was no difference between the two groups at the end of three months. Pain levels were decreased and function improved in both groups. And the improvements remained for over a year even after the programs were stopped.

Exercise was the main reason patients improved. There did not appear to be any added benefit from doing EMS along with exercise for PFPS. The results of this study support the previously reported idea that increasing extensor strength and balancing the quadriceps muscle inhibits knee pain.

But they found something else of interest. Pain relief didn’t occur because of improved muscle strength. The strength values of the quadriceps muscle (isometric contractions) did not increase as a result of the training program.

It’s likely that the changes occurred as a result of neurophysiologic changes, rather than any increase in strength. If that is true, then it is possible the EMS had a role in improving the timing and activation pattern of the quadriceps muscle. The authors suggest further studies to look at (and compare) the potential of neurophysiologic effects of exercise versus EMS.

There’s a new method emerging for surgical repair of a ruptured quadriceps tendon. The standard repair uses interlocking continuous sutures. The ends of the torn tendon are reattached through holes drilled in the patella. The new technique uses suture anchors.

In this report, surgeons from the University of North Carolina – Chapel Hill describe the new approach in detail. Drawings and patient photos are used to show the surgeon how it’s done. Five case examples are reported to help us understand how and when this procedure is used.

Suture anchors can be used for partial and complete ruptures. They can also be used in both acute (recent) and chronic (long-standing) injuries. In chronic injuries, the tendon may have retracted (pulled back) too far for this method alone. The surgeon will have to combine other techniques to make the repair.

Suture anchors are not advised if there is an infection or if the patient also fractured the patella (knee cap) at the time of the quadriceps rupture. Despite these few limitations, the use of suture anchors is expanding in many other areas of the body.

The authors point out the advantages of this method. Besides being a relatively simple technique, it reduces time in the operating room. After surgery, patients appear to have better resistance and minimal stress along the suture line during motion. The repair is stronger and less likely to fail compared with more traditional approaches.

The goal to restore motion as quickly as possible and prevent stiffness is met early with anchor sutures. Patients return to work and play much faster. The incision line is much smaller with this technique. That gives a better appearance afterwards but also means less tissue disruption during the surgery.

At the present time, there are only 10 reported cases of quadriceps tendon repair using suture anchors. More study is needed before adopting this approach. The authors suggest a study comparing results of the traditional approach with this newer method.

There aren’t very many long-term studies of results after surgery to repair the anterior cruciate ligament. And many changes have occurred in the last 10 years in the way this procedure is done. In this study, surgeons from France report on 101 knees with an ACL injury. All were repaired with the same bone-patellar tendon-bone (BPTB) arthroscopic graft technique.

In January 1993, they started a computer database of all patients having ACL reconstructions. Data gathered included patient age, time between injury and surgery, and symptoms. Joint laxity (looseness) was measured with a special device called the KT-1000 arthrometer.

X-rays were used to look at joint space and alignment. Function and sports activity were measured with the International Knee Documentation Committee (IKDC) classification tool. And it was recorded whether or not the meniscus (knee cartilage) had been removed.

The authors report about slightly more than half of the patients had a meniscal tear. Most of these were of the medial meniscus on side of the joint closest to the other leg. The longer the time between injury and surgery, the greater the chances for a meniscal tear. In the 11 years after the ACL repair, there were nine knees with a graft rupture. That’s about a nine per cent rate of reinjury.

Most of the patients were athletes. About 25 per cent did not return to sports play. The remaining 75 per cent did engage in sports activities. Not as many played contact or pivot sports. But this change wasn’t always linked with the surgery. In some cases, there were social and professional factors reported.

Overall, the patients were satisfied with the result of the surgery. The biggest subjective problem was painful kneeling (reported by half the patients). The most significant objective problem was osteoarthritis. Joint changes related to osteoarthritis were seen on X-rays in over one-third of the group. It does appear that ACL reconstruction protects the meniscus from injury. In this study being overweight was a risk factor for osteoarthritis.

The authors conclude that ACL reconstruction using a BPTB graft gives good long-term results. Patients have a nearly normal, stable knee a decade later. The procedure may have a protective effect to prevent further meniscal tears. Normal knee kinematics (movement) was also reported. Degenerative changes in the joint were more likely in older patients with a high body mass index (BMI).

It’s a known fact that women have more anterior cruciate ligament (ACL) injuries than men. This difference is seen most often in young athletes participating in noncontact sports.

There’s been some suggestion that perhaps the reason for this is the stiffness factor in the knee. In this context, knee joint stiffness refers to how much torsional spring there is.

How well does the joint respond to loads when the foot is planted firmly on the ground? Is there a difference in spring between men and women that could account for the differences in injury rates?

In this study, researchers measure the stiffness values in the knees of normal, healthy, college-aged men and women. The idea was to see if women have less stiffness than men at each point in the range of motion when load was applied.

A special device called the Vermont Knee Laxity Device (VKLD) was used to measure how much laxity (slack or looseness) was present in the knees front-to-back and side-to-side.

The amount of stiffness was remeasured as increasing amounts of torque were applied to the joint. Two types of force were used: varus/valgus and internal/external rotation. Varus and valgus force goes across the joint from one side to the other. Internal and external torque is a twisting motion inward and outward.

All measurements were taken with the leg in a non-weightbearing position. The same measurements were repeated with the foot in contact with a surface. A 40 per cent weightbearing load was applied through the foot to the knee. This load is similar to the amount of weight applied through the knee when the athlete was standing equally on both feet.

The authors report that women had lower stiffness values compared with men when low loads were applied to the knee. As the load increased, the joint stiffness also increased. This is different from men who have the same stable stiffness value no matter what load was applied.

This variable response to changes in load may help explain the knee biomechanics that lead to ACL injuries. Women may be especially affected when moving from a nonweightbearing to weightbearing stance. Women activate their muscles sooner than men when weight-shifting. Less joint stiffness combined with differences in muscle activation and recruitment may be important factors as well.

It’s possible that joint stiffness may be less important in men than it is in women. For women, changes in joint position, stiffness, and muscle function combined together may put the female knee at increased risk for ACL injury. More study is needed to sort this all out and find better ways to protect the female athlete from this type of injury.

This is the first of a three-part series on a condition called patellofemoral pain syndrome (PFPS). The focus of this article is on classifying the problem according to the biomechanics and treating it according to whether there is pain or instability.

The patellofemoral joint is the located where the patella (knee cap) meets the end of the femur (thigh bone). Patellofemoral pain syndrome causes pain under and/or around the kneecap. When there is instability, the patella slips and slides during movement. Dislocation of the patella is a common feature of instability-related PFPS.

The authors carefully explain the biomechanics of the normal knee. Understanding the way the structures of the patellofemoral joint move and function is important when treating this condition. The physical therapist must strengthen the correct muscles to balance the forces around the joint. Too much pull in one direction can cause additional problems.

The main symptoms of PFPS are pain along the sides of the patella. The pain may travel to the back of the knee. Load on the patellofemoral joint and the joint’s response to that load vary from patient to patient. That’s why each patient has his or her own unique rehab program for this problem.

For patients who feel like the kneecap is loose or slipping, there may be an actual patellar subluxation (partial dislocation) or full dislocation. Every time the patella dislocates, there is pain but also inflammation. Patellar dislocation is often the cause of cartilage tears and patellar bone fractures.

Once the patella has dislocated, recurrent dislocations are common. After the second dislocation, the other knee is at increased risk of a first dislocation. Some people are more susceptible to patellofemoral joint dislocations than others.

Risk factors include family history of patellofemoral dislocations and a personal history of developmental dysplasia of the hip. Women are more likely to have more than one dislocation. Shortened and tight or loose and lax ligaments can also create patellofemoral problems.

The next part of this series will present the examination of the patellofemoral joint. That will be followed by a third part discussing various ways to treat this problem.

The authors of this study take on a big task of comparing results for different surgical methods of repairing cartilage injuries. All of the operations were performed on athletes. The goal was to return them to play at a pre-injury level.

Four major types of repair methods for articular cartilage are reviewed. A description is given for each one. Advantages and disadvantages are discussed. And the latest results in research are reported. These four methods include:

For years, surgeons have used the tried and tested bone-patellar tendon-bone graft repair for anterior cruciate ligament (ACL) repairs. But more and more there are an increasing number of other repair options available.

In this update, surgeons from the University of Maryland review the autograftchoices. Autograft means the tendon harvested and used as a graft to replace the torn ligament comes from the patient. The four main types of autograft include 1) bone-patellar tendon-bone, 2) hamstring, 3) quadriceps, and 4) bone-hamstring tendon-bone.

Type of graft is important but so is graft fixation. Fixation refers to the method used to hold the donor tissue in place until healing occurs. Most of the fixation methods involve the use of tissue bundles. For example, there’s the double-bundle technique and the four-stranded and eight-stranded techniques.

Other graft fixation options include femoral press-fit, femoral cross-pin, screws, and endobutton femoral fixation. The authors describe each of these and review when surgeons are most likely to use each one. The results of recent research using any of these fixation methods is also summarized.

After looking over all of the recent publications, there wasn’t a clear number-one-best-choice for ACL graft repair. Little difference was seen in results between the hamstring tendon and bone-patellar tendon-bone autografts. Not enough studies have been done using the single- or double-stranded technique to form a clear decision.

Other areas that remain unclear include the best type of bundle technique to use. Likewise, it’s not possible to measure rotary stability of the knee after surgery. This makes it difficult to compare results from method to method. It was possible to see that several of the fixation methods (e.g., metal screw, bioabsorbable screw, endobutton femoral fixation, trans-fix femoral fixation) are equal in results.

It seems at the present time that there are more unanswered questions than answers to the dilemma of choosing the best repair and fixation techniques for ACL injuries. More studies are needed to come to some firm conclusions in this area of surgery.

The posterolateral corner (PLC) of the knee is made up of a group of muscles and ligaments that stabilize the joint. Injuries to the PLC often occur when some other area of the knee has been damaged.

In this article, surgeons from the University of Pennsylvania bring us up-to-date on PLC injuries. They provide information on the anatomy and biomechanics of the injury. How the injury occurs and most common symptoms are discussed. The authors walk the reader through the diagnosis and treatment step-by-step.

PLC is linked most often with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) tears. The most common mechanisms of injury are sports-related trauma, car accidents, and falls. It’s easy to miss the diagnosis of PLC injury when symptoms of other injuries are more pronounced.

An accurate diagnosis requires a careful history and examination. Tests specifically for this injury are presented. Imaging studies include X-rays, CT scans, and MRIs. MRIs offer the best view of the PLC. MRIs also show other injuries such as fractures, bone contusions, and other ligamentous damage.

PLC injuries are treated based on the grade of injury and when the diagnosis is made (acute versus chronic injury). Injuries are graded as I (no abnormal joint motion or instability), II (abnormal joint motion), and III (complete tear with joint instability). Arthroscopy may be done to see how severe the damage is and the location of any problems. Surgery to repair or reconstruct the PLC structures is often needed.

Surgical techniques used (approach, incision, methods) are presented for both acute and chronic injuries. Scar tissue, joint malalignment, and joint instability make the chronic injury a challenge. The surgeon must decide whether to restore the normal PLC anatomy or stabilize the joint by tightening up the soft tissue structures.

Complications are always possible with any surgical procedure. With surgery to manage PLC injuries, damage can occur to the peroneal nerve. Wound infection, knee stiffness, and hamstring weakness are also possible. Many of these problems can be avoided with careful surgical technique and the right rehab program.

Patients who live with patellofemoral pain syndrome (PFPS), pain in the anterior, or front of the knee, find that it gets worse as they walk up or down hill, squat, kneel, or sit with their knees folded in. It’s a fairly common pain syndrome, say researchers, with about 20 percent of the population experiencing it at one time or another.

At this point, there is no set guideline for assessing, diagnosing or managing PFPS, but there have been several theories about what causes the pain. One such theory is that it is caused by a local nerve injury and results from pressure from neighboring bones. When researching the physical aspects, x-rays have not shown any definite findings that could explain the pain and what causes it.

The authors of this study assessed whether PFPS could be classified as neuropathic pain, or pain that is related to the nerves.

Researchers recruited patients with PFPS in one knee and 56 men and 35 women between the ages of 18 and 40 years participated in the study. A control group of 12 women and 11 men also participated. None of the subjects in the control group had any knee pain and all had normal knee function.

To assess the pain, researchers used quantitative sensory testing (QST), a method that is used to evaluate sensory nerve fiber function, and various instruments to check sensations to vibration and heat. The researchers used the visual analog scale (VAS) a score of 0 to 100, with 0 being reports of no pain and 100 being the most severe pain possible. The Cincinnati Rating System was used to determine level of knee function by evaluating symptoms of knee pain, swelling, giving-way, and function (walking, stairs, running, jumping/twisting). A functional performance test is also performed. The Step-Down test assesses the ability of the knee to function stepping up and down a 20 centimeter platform.

When gathering the results, the researchers found that the average age of the study subjects was 31 years and the average length of time they had the knee pain was about 70 months. The average body mass index of the subjects was 25.3. No-one had not taken any medication for their knee pain on the day of testing, but four had taken NSAIDs (non steroidal anti-inflammatory drugs) within the week before the test.

Comparing the results of sensation and the results from the scale measurements, the findings did not show any differences in sensation between the knees of the study group and the knees of the control group. The researchers did find that there was localized damage to the nerve channels, but they were unable to “identify a subgroup with probably neuropathic pain.”

The authors of this article note that there is no gold standard for identifying neuropathic pain so there are no real tests for it. However, using certain criteria, it is possible to form a profile. Comparing the test results between the group with pain and the control group, the researchers found that, although the patients with pain had altered nerve sensation in the knee, there was no clear subgroup of patients who had features of neuropathic pain.

In this study, 41 cases of hamstring avulsion are reviewed. The hamstring muscle is along the back of the thigh. There are three main parts: the biceps femoris, semimembranosus, and semitendinosus. Avulsion means the tendon has torn completely away from the bone.

The cause, mechanism of injury, and symptoms are presented. Surgical technique for reattaching the muscle is described. Sometimes there wasn’t enough tissue to work with. A tendon graft from the iliotibial band (or tract) was harvested from the same side. The iliotibial tract is a layer of fibrous fascia along the outside of the thigh.

Results of surgical treatment are the main focus of outcomes in this study. Acute cases (early surgery) were compared to patients treated in the chronic phase (surgery was months to years later).

Results for each patient were rated as excellent (no symptoms/normal function), good (mild symptoms/normal activity), moderate (painful symptoms/loss of function), and poor (function impaired by significant symptoms).

Most of the athletes in the study had excellent or good results. Two-thirds were able to return to their preinjury levels of sports activities after surgery. A delay in having surgery was linked with a poor result. Patients with delays greater than six months had the worst results.

The authors recommend immediate surgery for acute cases of hamstring avulsion. Nonoperative care is usually unsuccessful. The delay in surgery can mean a poor result. With delays, scar tissue and adhesions form.

Scarring and adhesions can wrap around the sciatic nerve. Sciatica with pain and numbness in the buttock and down the leg may develop. Muscle weakness and atrophy can occur. The hamstring tendon retracts and can’t be pulled back in place to reattach it. The sciatic nerve can get entrapped inside the retracted muscle. When any of these things happen, there can be irreversible damage to the nerve. The surgery is more complex. A tendon graft may be needed.

The good news is that even with delays in surgery, patients can have a good result after repair of a hamstring avulsion. Athletes are able to return to their sport at a level equal to their preinjury level of participation. Carefully following the surgeon’s directions and completing a rehab program can yield considerable improvements (even years later).

Surgery to reconstruct a ruptured or deficient anterior cruciate ligament (ACL) may affect the placement and movement of the patellofemoral joint (PFJ). The patellofemoral joint is where the patella (kneecap) moves against the femur (thigh bone). Whether there is a change in patellofemoral kinematics (motion) after ACL reconstruction remains unknown at this time.

In this study, special computerized MRIs were used to create a three-dimensional (3D) view of the knee joint. Contours of the bone and cartilage surfaces were mapped out for the knee. This information was used to analyze patellofemoral kinematics.

Eight patients were included in the study. All were treated for ACL deficiency by one orthopedic surgeon. A bone-patellar-bone autograft was used in all cases. The author described the specific surgical technique used.

Another type of imaging method called fluoroscopy was used to view the knee position and angle during single-leg forward lunges on the involved side. The same information was gathered on the normal, healthy knee in each patient. Images were imported into a software program.

The position and angles of the knee helped identify the patellar tendon kinematics. Patellar flexion, rotation, tilt, and shift were viewed and compared from normal to operative side.

They found that reconstruction of the ACL did not restore the normal function of the patellofemoral joint. Changes in patellar tracking and patellofemoral cartilage contact points altered the normal function of the joint.

ACL reconstruction restores knee joint stability. It even improves patellofemoral joint function. But it doesn’t completely restore normal patellofemoral kinematics. This means there could be uneven wear patterns that lead to degenerative changes in the knee.

These findings may explain why some patients with a bone-patellar tendon-bone graft report patellofemoral pain after surgery using this type of tendon graft.

A common cause of knee pain in young athletes is called patellofemoral pain syndrome (PFPS). The patella (kneecap) moves up and down over the femur (thigh bone). This motion occurs along a specific track of cartilage along the back of the patella over the end of the femur bone. Pain with PFPS can occur when the patella gets off track and moves unevenly.

Studies have shown that lumopelvic manipulation of the sacroiliac joint (SIJ) can restore function of the quadriceps muscle. The quadriceps muscle along the front of the thigh pulls on the patella to straighten the knee. This muscle plays an important role in the development of PFPS.

The focus of this study was the effect of SIJ manipulation on PFPS symptoms. The researchers were a group of military physical therapists (PTs). A second goal of the study was to identify patients with PFPS who might benefit from SIJ manipulation.

Finding common factors that predict the outcomes of treatment is an important research goal. If PTs can recognize PFPS patients who would benefit from SIJ manipulation, faster and better outcomes from treatment might be possible. After studying 50 men and women with PFPS using lumbopelvic manipulation, here’s what they found :

Injuries to the anterior cruciate ligament are common among young athletes. Most of these ruptures occur as a result of a noncontact event. Usually, the athlete is landing from a jump with the knee in just the right amount of torque to rupture the ligament. But whether from a noncontact or contact injury, the exact mechanism of injury remains unknown.

In this study, researchers used MRIs to identify patterns of bone bruising in athletes with ACL injuries. Studying the impact on bone at the time of injury was helpful. They compared the depth, location, and intensity of bone bruising with the amount of energy generated in the knee at the time of the injury.

They found that there was much more bruising in the bone of the noncontact group. The greater amount of bruising in this group points to a larger amount of energy and more damage done with a noncontact injury.

Most of the bone bruising associated with ACL ruptures in both groups occurred in the lateral compartment of the knee. The mechanism of noncontact injuries leading to ACL rupture was characterized as translation (movement) of the tibia(lower leg) on the femur (thigh bone). There was internal (inward) rotation of the tibia at the same time. Injury to the medial compartment was much more common with noncontact ACL injuries than anyone had known previously.

The mechanism for the contact group was more of a mixed picture. With most ACL contact injuries, there was a major valgus force. Valgus force refers to getting hit from the outside of the leg. The force translates through the knee to the inside of the leg.

The long-term significance of bone bruising is unknown. MRIs show that the cartilage cells called chondrocytes do undergo change. There is thinning of the cartilage surface in the area of the bone bruise. Laboratory analysis of the chondrocytes confirms damage to the cells. Further studies are needed to assess the long-term effects of bone bruising.

Studies have shown that muscle strength and function don’t return fully in the leg after a total knee replacement (TKR). Motion analysis shows weakness and compensation patterns persist in the involved leg. These differences are seen as much as one year after the surgery.

In this study, physical therapists from the University of Delaware use a specific test to measure strength, function, and movement patterns one year after TKR. Patients included in the study had the same kind of TKR procedure and implant. The incision used extended into the quadriceps femoris tendon.

The TKR patients were tested using a standard test called sit-to-stand. Using a backless, armless chair, everyone stood up from a sitting position. The arms were folded across the chest or held in the lap. A second (control) group without TKR was also tested in the same way.

A 3-D, 6-camera motion analysis system was used to capture and analyze the motion. Two forceplates were placed on the floor (one under each foot). The forceplates measured ground reaction forces under each leg during the sit-to-stand task. The time to complete the task was recorded.

Several other tests were also performed. Electromyographic (EMG) activity of the quadriceps muscle was used to measure strength. The Timed-Up-And-Go (TUG) test, the Six-Minute-Walk-Test (6MWT), and the Stair-Climbing-Test (SCT) were also given. These three tests measure functional strength of the quadriceps femoris muscle.

All tests were given three months and one year after the procedure. Joint angles, forces, and amount of muscle activity were compared from side to side and with the control group. The authors were expecting the TKR group to have differences in results (compared to the control group) at the 3-month follow-up check. They expected to see similar results by the end of the one-year time period.

What they found was that the TKR group continued using compensatory movement patterns for the sit-to-stand test. Instead of using the hip flexor muscles, they were still using hip extensor muscles. In fact, they were using the hip extensor muscles even more at the end of 12 months compared to the three-month measurements.

This altered movement strategy helps reduce the demand on the knee extensor muscles (quadriceps) and unloads the involved leg. The authors say that altered movement strategies at three months are to be expected. But by the end of one year, strength is equal from side to side. So this type of compensation movement pattern is no longer needed.

Physical therapists need to be aware of abnormal movement patterns after TKR. Training to restore normal movements is important. Equal weight-bearing, strength, and forces on the joint may help avoid uneven load. The goal is to prevent movement patterns that can lead to future arthritic changes in the joint.