News Category: Knee

With the increased number of athletes of all ages, there has been a steady rise in the number of anterior cruciate ligament (ACL) injuries. Surgery to repair the damage involves the use of graft materials to replace the ligament. Despite improved surgical technique, 25 per cent of the grafts fail.

In this study, surgeons from Germany investigate the reasons for graft failure. They present the mid- to long-term results of ACL revision surgery using autografts. An autograft refers to tissue taken from some other part of the patient’s body. The harvested tissue is used to replace the torn ligament. The most common autografts for ACL repair are from the patellar tendon or the hamstrings tendon.

The authors describe their graft technique. Holes are drilled in the bone to create a tunnel through which the graft is inserted. Graft fixation was done using sutures but without any hardware (screws, wires, or metal plates).

Simple to more complex revision methods are discussed. The extent of surgery depended on the condition of the cartilage and meniscus. Malposition of the tunnel from the first surgery was a major reason for graft failure requiring correction.

Outcomes were measured using physical and radiographic examinations. Several tests of function, range of motion, and strength were also used. The surgeons made note of the timing of the revision surgery (e.g., within first 12 months after ACL repair). Any signs of joint degeneration or arthritic changes were also recorded. Everyone was followed for at least three years.

The authors report ACL revision surgery was able to provide function and stability to most of the patients in the study. The most common causes of failure included tunnel malposition, reinjury, and use of a synthetic graft.

Most of the patients reported improved quality of life after ACL revision surgery. Even so, two-thirds did not return to their preinjury level of activity. This was due in part to the fact that many of the patients were older (30 to 50 years old). They chose not to return to a higher level of activity.

X-ray results also showed signs of progressive osteoarthritis for nearly 80 per cent of the patients. This was compared to 40 per cent before the revision operation. The rate of osteoarthritis was less in patients who had early revision surgery. Early revision has better results because the knee cartilage is in better shape with less meniscus damage.

Athletes are known to be at high risk of developing osteoarthritis of the knee due to increased weightbearing activities and high impact “loading.” These injuries first present as articular cartilage defects of the knee, mostly lesions found on the femur, or thigh bone.

Doctors commonly classify the cartilage injury with the Outerbridge and International Cartilage Research Society (ICRS), however the authors of this study propose a new score called the Chondropenia Severity Score (CSS), which takes into account the curve inside the knee.

In diagnosing articular cartilage lesions, doctors use a combination of patient history, clinical examination and results from x-rays and scans. Treatment involves surgical repair through lavage (cleaning), debriding (removing dead tissue), drilling, or microfracture, introducing small holes in the bones to allow marrow to seep out and harden.

Of the various methods of treatment to repair the cartilage, there does not appear to be one superior form as the treatment depends on the extent of the injury and the patient him or herself. The aim is to return the patient to his or her previous level of activity with a minimum of discomfort, without increasing the risk of osteoarthritis later on in life. A newer technique, articular cartilage regeneration is proving promising.

In this procedure, cultured chondrocytes (cells) are used to regenerate tissue, thereby healing the injured cartilage. The authors of this article write, “long-term studies … will determine the efficacy of articular cartilage repair to reverse chondropenia and prevent development of secondary arthritic degeneration.”

Total knee replacements (TKAs) that become infected can be very difficult to treat effectively. Despite a high cost for the treatment, the outcome may not always be ideal, leaving patients with pain and decreased mobility.

As with most complications, prevention is the best medicine. This involves identifying patients who may be at higher risk of developing infections following TKAs. That being said, the appropriate treatments must be identified once infection has set in.

the signs and symptoms of infection in a TKA are usually the obvious ones of pain, difficulty in movement, mild inflammation and recurrent effusions (fluid in the knee). Blood tests can also indicate the presence of infection. Joint aspiration, withdrawal of fluid from the joint, is another method of diagnosis but could require several samples before an infection is found. Other methods, such as scans may not detect infection within the first year after surgery, because of how the joint is healing.

Treatment of these infections can be done through conservative methods such as antibiotics, right through to more aggressive methods, such as replacing the joint or even amputation. The choice of treatment greatly depends on the patient, the patient’s lifestyle, and – of course – the infection itself.

Eliminating the infection completely is the ultimate goal. If debriding, or cutting away of infected and dead tissue, is performed, it must be done meticulously and completely if the goal is to keep the current joint. It would be necessary to remove the liner in the knee to be sure to access any surfaces hidden or inaccessible below the liner. The authors of this article write that such a procedure is more likely to be successful if the infection is caused by the Staphylococcus epidermis bacteria and not as successful if it is caused by the Staphylococcus aureus bacteria. As well, for this procedure to work, it is important that the infection has not been present for more than three weeks and the patient is not immunocompromised.

If debriding and antibiotic treatments are not an option, amputation or replacement may be necessary. The type of surgery will greatly depend on the remaining healthy bone and ability to tolerate another replacement. There is a two-step procedure that is an option for some patients. This includes removing the infected implant and replacing it with a temporary spacer, while administering antibiotics to the area. If the surgery is done without using a spacer, the patient can run into problems with the joint a few weeks later when a new implant is attempted. Spacers allow the knee to stay in the proper position and prevent contractions and the build up of scar tissue.

The two-step or two-tier option has become increasingly popular in situations where the infection is not treatable in the less invasive methods. The authors conclude, “For deep infection of more than three weeks’ duration, most expert surgeons recommend a staged approach to management.”

Pain and snapping along the outside border of the knee can be caused by a variety of problems. It could be iliotibial friction syndrome, meniscus tear, degenerative joint disease, or even a loose fragment in the joint.

In this report, the case of a 21-year-old female with a painful snapping of the left knee is presented. She had the symptoms for seven years. Evaluation and treatment by a variety of doctors and physical therapists were not helpful.

She had to give up all sports and recreational activities. Any activity involving knee flexion or extension seemed to set it off. Even walking became a painful process. Her goal to return to running seemed impossible.

She was seen by the authors of this case report (an orthopedic surgeon and a physical therapist). After a thorough examination, it was determined she should try another round of physical therapy treatment. The therapist used a trial of manual therapy, taping, icing, and a knee immobilizer.

Conservative (nonoperative) care was unsuccessful. Pain was relieved but only temporarily. As soon as the treatment was stopped, the pain returned. The surgeon performed an arthroscopic exam followed by open surgery to find out what was causing the symptoms. He found that the snapping was caused by the popliteus muscle as it moved over a tubercle (bump on the bone).

The popliteus is a muscle between the femur (upper leg) and the tibia (lower leg). It crosses the knee and helps rotate the tibia on the femur when the foot is planted on the ground. It also unlocks the extended knee when walking.

The surgeon removed the tubercle and moved the popliteus tendon to a new attachment. The new location of the tendon helped decrease how much the tendon moved during knee flexion and extension. The surgeon checked during the operation to make sure that the tendon was no longer snapping as the knee joint moved.

The painful snapping was eliminated with surgery. After completing a rehab program, the young woman was able to resume all activities. Conservative care is always recommended first before considering surgery. Three out of four patients with this problem are helped by nonoperative care. For that one patient who does not respond to physical therapy, surgery may be needed.

Exercise is important for patients with knee osteoarthritis (OA). Strength training has been shown to help younger adults with OA. But how important is this type of exercise for older adults with knee OA?

In this study, physical therapists from Taiwan compare the effects of low resistance exercise to high resistance exercise. Three groups of patients over the age of 50 were included. Everyone in the study was diagnosed with knee OA affecting both knees.

Group one received low-resistance exercise. Low-resistance refers to low weights (load) with many repetitions. In this study, group one did 10 sets of 15 repetitions of each exercise. The weight used was determined by their baseline level of strength at the start.

Group two completed a high-resistance exercise program. They used more weight with fewer repetitions (eight) and fewer sets (three). Everyone did three training sessions every week for eight weeks. The exercises were prescribed and supervised by an experienced physical therapist. Group three (control group) did no exercise.

Results were measured in terms of pain, function, and walking time. Walking was assessed on level ground and while going up and down stairs. Pain was measured for several separate activities. These included walking, sleeping, sitting, and standing.

Function was a measure of general activities such as bathing, housework, and every day tasks. Strength was measured using a special testing tool called an isokinetic dynamometer. All measures were taken before and after the exercise treatment.

The authors reported at the end of the study that both exercise groups had less pain and had improved in strength. Walking speed was also increased on flat and uneven ground. The high-resistance group got better results than the low-resistance group. But it wasn’t enough difference to be considered significant.

There were a few patients who could not handle the higher level resistance program due to increased knee pain during the exercises. No change in any measure was observed in the control group.

The results of this study support outcomes of other studies that show strength training reduces pain and improves function in older adults with knee OA. Improving muscle strength around the knee increases general knee joint stability. This is important when it comes to functional activities such as getting up out of a chair and walking or climbing stairs.

For those patients who can handle high-resistance training, the exercise program takes less time than low-resistance exercise training. Training programs for knee OA should also include agility tasks, balance training, and aerobic conditioning.

Many surgeons wait three weeks before doing surgery to repair a torn anterior cruciate ligament (ACL). The belief is that loss of motion and poorer results occur after early surgery. And anyone with limited motion or bleeding into the knee joint should wait to have surgery. Is this wait really necessary?

In this study, active duty military men and women with an acute ACL tear were divided into two surgical groups: early (within three weeks) and late (after six weeks). Half of the early group did have the surgery within one week’s time of the injury. Everyone had the same surgical procedure done: an ACL reconstruction using their own hamstring tendon grafts. The rehab program was identical for each patient, too.

Patients in the delayed surgery group were not allowed to participate in sports or military duty during the waiting period. Everyone was tested before and after the surgery. Measurements taken included range of motion, strength, and activity scores.

Patients were evaluated every six months for up to three years. The results showed no difference between the two groups. Loss of knee extension can be a problem for some patients after ACL repair. Only one patient in either of these two groups had this problem. It was not considered significant or linked to the timing of the operation.

The authors suggest that doing the reconstructive procedure early subjects the knee to only one trauma instead of two. They also found that patients felt better when treatment was delivered faster.

In a military setting where every day counts, delaying surgery while continuing to train and drill with the unit can result in more damage to the joint. When surgery must be delayed for any reason, patients should be protected from high-level performance activities to avoid such damage.

It appears that ACL reconstructive surgery doesn’t have to be delayed to protect the knee and obtain a better result. In fact, it may be more the case that early surgery for an acute ACL injury will result in better outcomes. This study was done on active duty servicemen and servicewomen. Similar results may not occur with patients who are not military or athletic.

Studies show that joint laxity (loose ligaments) in the knee can lead to anterior cruciate ligament (ACL) rupture. In this study, researchers look to see if patients with excessive joint laxity have different results after ACL surgery depending on the type of tendon graft used to repair the rupture.

Two groups of patients were compared. Everyone had an ACL tear and needed reconstructive surgery. The first group had normal joint laxity. The second group had generalized joint laxity (present in all the joints).

Two different types of standard tendon grafts were used in both groups (hamstring graft and bone-patellar tendon-bone graft). It was expected that the patients with joint laxity would have different results depending on which type of graft was used.

One surgeon did all of the operations. The surgical technique was described for both grafts. Everyone had the same postoperative rehab program. X-rays were taken before and after the procedure. The images were uploaded to a special computer program for analysis.

Results were measured based on pain, function, and amount of anterior translation in the knee. Anterior translation refers to the forward sliding motion of the tibia (lower leg bone) under the femur (thighbone). Translation is a measure of knee joint laxity.

There was no difference in results between the two grafts for the normal group. But knee joint laxity was greater in the laxity group when the hamstring graft was used. The authors suspect several reasons for this difference. The first is that the hamstring tendon is smaller in diameter compared to the patellar tendon graft.

Second, the hamstring tendon is folded over on itself and then placed inside a tunnel formed in the bone. This graft is slower to bind to the bone compared to a patellar tendon graft, which uses bone plugs instead of a tunnel. It appears that the hamstring tendon forms a fibrous envelope around itself instead of attaching firmly to the surface of the bone.

The final outcome of this study was to show that the bone-patellar tendon-bone graft is a better choice for ACL repair in patients with generalized joint laxity.

Pain, loss of motion, and limited function are the main reasons older adults choose to have a total knee replacement (TKR). And though many obtain pain relief, range of motion and function are not always fully restored.

But what is the optimal range of motion needed in the knee for everyday activities such as walking and climbing stairs? This study from the Center for Hip and Knee Surgery at St. Francis Hospital in Indiana takes a look at this question. They went back and reviewed over 5,500 patient charts who had a TKR.

A comparison was made between motion, pain, walking and stair-climbing ability, and knee function before and after TKR. Everyone had a posterior cruciate-retaining implant. This type of knee replacement leaves the posterior cruciate ligament (PCL) intact. The PCL helps hold the knee stable and prevents too much backward motion of the tibia under the femur (thighbone).

Previous studies have shown that 90-degrees of motion is needed to go up and down stairs. Getting up from a chair requires just slightly more motion (93 degrees). And lifting an object requires at least 117-degrees of flexion.

These movements and activities are all that are needed by most adults in a Western culture after TKR. Adults in other cultures requiring more squatting, kneeling, and sitting cross-legged need between 111 and 165 degrees of knee flexion to use these positions.

The results of this study showed that patients with posterior cruciate-retaining TKRs had the least pain and best results when their knee flexion motion was 128 to 132 degrees. There wasn’t much difference in function for patients with range of motion just above or below these figures. But stair climbing was improved with motion between 133 and 150 degrees.

The authors concluded that at some point, there may be a limit to the benefits gained by a higher range of motion after TKR. Patients who get between 128 and 132 degrees of knee flexion seem to have good function for everyday activities. Anyone who engages in activities requiring kneeling, squatting, or sitting cross-legged may need additional rehab to obtain enough motion to accomplish these tasks.

Shin splints, stress fractures, and compartment syndrome are the three most common causes of lower leg or shin pain in athletes. Runners are especially prone to these types of overuse injuries.

A correct diagnosis is needed to ensure proper treatment. But symptoms are often the same or similar making an accurate diagnosis difficult. In this article, the causes of shin pain, their diagnosis, and treatment are reviewed.

The physician must rely on the history and physical exam. Was there an injury? What kind of specific trauma occurred? What are the symptoms? Where is the pain located? The exam includes evaluation of motion, gait (walking pattern), tenderness, flexibility, and strength.

Some tests are as simple as squeezing the soft tissues or single-leg toes raises, which stress the muscles and tendons. X-rays may be needed to confirm stress reactions or fractures. But X-rays only show fractures half the time when they are really there. So when diagnosing stress fractures, a bone scan is the current gold standard.

For a compartment syndrome, the exam is followed by measuring the compartment pressures. A compartment syndrome is a dangerous increase in pressure of the areas of soft tissue inside the lower leg. Measures are taken before and after exercise. Muscle volume changes with activity. If the connective tissue separating the compartments can’t respond to muscle volume expansion, then compartment syndrome may occur.

Treatment for shin pain depends on the underlying cause of the symptoms. Often, rest and inactivity are advised for shin splints and stress fractures. Establishing a diagnosis of compartment syndrome is important because surgery is often needed to prevent serious complications from developing.

Computer-navigated total knee arthroplasties (replacements), or TKAs, are improving the accuracy of the implantations and studies are finding that navigation-assisted surgery is providing better outcomes in terms of alignment of the femoral (thigh) and tibial (shin) components. However, because the navigation is performed before the actual manipulations, optimal positioning is not always obtained.

Errors causing misalignments can result from any of the many steps in the surgical process, from the accuracy of the navigation system to the application and manipulation of the cemented or cementless components. Up to now, previous studies have investigated the accuracy of the navigational systems and have found great differences between the results.

What seems to be a particularly important issue but one that is not given a lot of notice, is the final positioning of the femoral and tibial components. While the navigational systems check the alignments throughout the process, checking after the final positioning is rarely done.

The authors of this study wanted to see how measuring the positioning after final alignment would affect the outcome. Researchers enrolled 91 patients who were to receive a primary TKA because of osteoarthritis. Patients who were having revision surgery, or who had infections or knee instability were not candidates for this study. At the beginning of the surgery, the surgeons attached navigation trackers to measure placement. The positioning was measured at set times throughout the procedure and, unlike other studies, again after the components were in place and the cement had hardened.

The results showed that there were deviations in the angles ranging anywhere from zero to three degrees, regardless of how carefully the surgery was performed and how accurately all the steps were completed. Therefore, even careful measurement throughout surgery, does not always result in optimal results.

Most surgeons advise sports athletes to wear a brace during play after surgery to repair a torn anterior cruciate ligament (ACL). But which one works best? Should you use a neoprene sleeve or one of the more expensive functional knee braces? Does it matter? Does one give better support or control than the other?

These are the questions posed by researchers from the School of Physical Therapy at the University of Western Ontario in Canada. To find out the answers, they divided a group of ACL patients who had reconstructive surgery into two groups. The first group received a sleeve six weeks after the surgery. The second group was given a brace at the same time.

Everyone wore their supportive device when engaging in any physical activity. This included rehab exercises and any activities that could strain the knee. Running, jumping, twisting, cutting, and pivoting are examples of activities for which the sleeve or brace was worn. In addition, support was required for any activities on uneven ground or involving quick stops and starts.

Results were measured based on perceived quality of life, joint laxity, activity level, and one test called the hop test. The hop test required hopping forward on one foot for a specified distance. Quality of life included work-related concerns, emotional well-being, symptoms, and the ability to participate in leisure time activities and recreational sports.

Patients were followed for two years. In the end, there was no difference in results between the two supportive devices. Athletes wearing the more rigid brace support did not have better results compared to sports participants using the sleeve. The brace group did have greater confidence that their device gave them more support.

The authors suggest that there may be specific subgroups of patients who might benefit from bracing more than others. For example, women under the age of 25 years had higher scores for quality of life when wearing a brace compared with a sleeve. How soon surgery is done after the injury may make a difference.

More studies are needed to identify potential subgroups who should use a support after ACL repair. The type of support may not matter but this should be examined more closely as well.

Athletes are often unable to maintain fitness when recovering from surgery. This can cause physical decline and set them back. In this study, researchers compare ways to keep up with muscular and cardiorespiratory deconditioning. Treatment with two forms of aerobic exercises were compared.

Fourteen male soccer players recovering from knee surgery were tested after using an arm-cranking device and after performing a one-leg cycling activity. The arm-cranking device involved the use of both arms at one time. The one-leg cycle just exercised the leg that wasn’t operated on. Both activities were done at a maximal graded aerobic level.

This means their respiratory exchange ratio (RER) was more than 1.10. RER is a measure of gas exchange and cardiopulmonary function. Heart rate was within 10 beats of the predicted maximal level for their age.

Other measures of results included rate of perceived exertion (RPE) and blood samples of blood lactate concentration. RPE is a self-reported sense of how hard the athlete is working while exercising. Numbers along the PRE scale are used to report a range from no exertion to maximal exertion.

Blood lactate concentration is a measure of lactic acid in the blood. It is used to document the lack of oxygen to the muscles. It can be used to monitor the effect of treatment with exercise.

Results showed that either exercise works well for maintaining active muscle mass. Blood lactate levels and PRE were both higher for the arm cranking exercise. This could mean that the arms were getting less blood during the activity compared to the leg during cycling.

The authors suggest using one-leg cycling to maintain fitness for athletes after knee surgery. The cardiopulmonary benefits are equal to the arm exercises. The patient is more comfortable and perhaps more likely to keep up the exercise consistently.

Engineering experts have new information for us on the function of the posterior cruciate ligament (PCL). Using fluoroscopy and three-dimensional (3-D) computer models, the knees of patients with PCL injuries were examined. Fluoroscopy is a type of X-ray imaging that allows a view inside the moving joint.

MRIs were used to scan both knees of each patient in the study. The information was used by a computer to create a 3-D model of the patient’s knees. The computer program created a coordinate system for the tibia (lower leg bone) and the femur (thighbone). This information was used to identify the axis (center) of motion for flexion.

A fluoroscopic system was used to measure and record knee joint kinematics. This was done with the patient in a standing (weight-bearing) position while lunging forward. Kinematics refers to joint motion that occurs from all angles and directions.

Using these two systems together, the engineers were able to map out and measure tibial translation (glide) in all planes of motion. They looked at how far the tibia moved backwards, sideways, and in a rotatory direction in the PCL-deficient knee. These measures were compared with the normal knee.

The results showed that the tibia moves forward relative to the femur during knee flexion. The amount of forward translation was less in the PCL-injured knees. As the knee bent to 90-degrees of flexion, the tibia also slipped sideways in the PCL-injured knees. Internal rotation of the tibia during flexion was the same between the injured and normal knees.

Many studies have shown degenerative changes occur over time in PCL-deficient knees. The authors of this study suggest these osteoarthritic changes may be caused by the change in contact points and increase in contact pressures within the joint when the PCL is damaged. The lateral movement of the tibia may shift these contact points.

Kinematic studies like this one show that the PCL’s function in the knee is more complex than just to maintain posterior stability (keep the tibia from sliding backwards). Surgeons must take this information into consideration when reconstructing the knee after a PCL injury.

Do men and women have different success with total knee replacement (TKR) based on anatomy? We know there are many differences in the bony anatomy of the male versus the female knee. Do these differences make a difference in outcomes or results?

These are the questions addressed by this Technology Overview. This summary document is from the American Academy of Orthopaedic Surgeons (AAOS). They state clearly that they are not making recommendations, but providing a summary of findings in the literature. The Technology Overview is just a tool, not advice for patient treatment.

Men have larger femurs (thigh bone) compared with women. Size, height, and width of the bone are larger in men. There are anatomic differences in the patellofemoral joint. This is where the patella (kneecap) moves up and down over the femur. Details of these differences are described.

Although women have been reported to have a larger Q-angle than men, this may be related to height more than differences in anatomy. Men and women who are the same height have equal or similar Q-angles. Shorter people have higher Q-angles.

The Q-angle is measured by drawing one line from the middle of the patella to the anterior-superior iliac spine (ASIS) of the pelvis. Another line is drawn through the middle of the patellar tendon. The angle formed by these two lines is the Q-angle. Males should have a Q-angle between eight to 12 degrees. The normal female has a Q-angle between 12 to 15 degrees. Q-angles higher than 15 degrees for men and 20 degrees for women are abnormal and may cause problems.

In this report, a review of studies comparing results of men versus women was summarized. There was no proof that age, gender, or obesity are linked with functional outcomes after TKR. Overall, there were no real differences in outcomes for men versus women after TKR.

Revision rates, range of motion and scores on tests of knee function were similar between men and women. There was some evidence to suggest that women are hospitalized longer than men for this procedure. Men have a higher death rate after TKR compared with women.

Patients with patellofemoral pain (PFP) may have a laterally positioned patella (knee cap). If the patella doesn’t track up and down over the knee correctly, then the surface of the joint is overloaded. Uneven wear of the articular (joint) surfaces may lead to PFP.

There’s only one test reported so far that can be used to reliably measure patellar position. And studies are not consistent in their findings when using this test. Some find a difference in patellar position in patients with PFP and some don’t. Whether or not a laterally placed patella really leads to PFP remains a topic of debate.

In this study, 12 female patients with PFP were compared to 12 women matched by age and body mass without PFP (control group). Measurements of the patella position were made by one (experienced) physical therapist. The McConnell method of measurement was used (and described). An independent examiner repeated the measurements.

Everyone in both groups had a laterally displaced patella. The PFP group was significantly more lateral than the control group. The results confirm that patients with PFP have a laterally positioned patella.

And the study confirms this test is reliable and valid. When experienced therapists administer the test, the results are consistently the same. Training and experience using the McConnell method may be needed for accurate assessment of patellar position.

But we still don’t know for sure that this altered position is what causes PFP. There is general agreement that a laterally positioned patella is not normal. This is true even when everyone in both groups had a positive test result. Unless the patella is positioned centrally, there is an abnormal loading pattern of the patellofemoral joint.

More study is needed in this area. The first step remains to find an accurate test that can be used reliably by many researchers. Studies such as this one move us in the right direction.

New joint-resurfacing techniques are available to treat damage to knee joint cartilage. Without this treatment, the patient is at risk for disability from osteoarthritis. These new methods of cartilage regeneration include mosaicplasty, microfracture (MF), and autologous chondrocyte implantation (ACI).

It’s not clear yet which one of these procedures is best. The goal is to promote repair tissue that is as much like the natural articular cartilage as possible. Durability is especially important.

In this study, the results of microfracture were compared with chondrocyte implantation. Quality of regenerated tissue was assessed. Symptoms of pain and stiffness were measured. Other clinical outcomes included activities of daily living, function in sports and recreational activities, and quality of life.

Study design and specific surgical techniques were outlined for the entire study. Chondrocytes (cartilage cells) harvested for growth and expansion in a lab were mixed with ChondroCelect (CC). CC is produced by TiGenix in Belgium. It has the ability to preserve biologic activity of the chondrocytes once they are removed. This makes it possible to multiply the chondrocytes. Using a group of chondrocytes with a specific marker profile improves the ability of the chondrocytes to reproduce.

One year after either MR or ACI surgery, a tissue sample from the repair site was removed and tested. Type of cells, surface area, and thickness of cartilage were measured. Any signs of poor cartilage repair were reported.

Regeneration of the cartilage lining the joint surface was better in the CC implantation (CCI) group. There were also more chondrocytes-like cells. A denser matrix of cells gave the tissue higher compressive strength. This conclusion was based on histopathologic study of the tissues. Scar tissue instead of hyaline-like cartilage was observed more often after MF. Fibrous scar tissue is not as durable as hyaline cartilage.

Clinical outcomes were similar between the two groups. A significant number of patients in both groups reported adverse events. Joint pain and/or swelling were the most common effects. Overall, the CCI group had fewer problems. When there were adverse events in the CCI group, joint swelling and crepitation (crackling sound or feeling in the joint) occurred much more often than in the MF group.

The authors suggest that the use of a product such as CC provides a superior structural regeneration of cartilage tissue. This may lead to better long-term clinical outcomes. Further follow-up of these patients is needed to know for sure what the long-term benefits might be and if the short-term effects are maintained.

Deciding who needs surgery and who doesn’t after an anterior cruciate ligament tear is a challenge. Some athletes seem to be able to compensate well after ACL injury. They can return to sports at their preinjury level without surgery. These patients are referred to as copers.

Others have ongoing episodes of knee instability. The knee gives-way underneath them during activities. Athletes in this group are called noncopers.

In this study, researchers look to see if age, gender, or mechanism of injury are linked in any way to becoming a coper vs. a noncoper. The mechanism of injury was either contact or noncontact ACL injury.

Contact injuries occurred when there was a collision with another player or object. Noncontact injuries were more likely to occur when the athlete was pivoting, cutting, or jumping.

A series of tests and measures were used to screen for knee instability after ACL rupture. The screening exam included range of motion, strength, and the single-leg hop test. Patients also reported the number of times they had giving-way episodes. All participants in the study completed a survey of knee function.

Analysis of the results showed that women were more likely to be in the noncopers group. Athletes who had a noncontact ACL injury were also noncopers. Copers seem to have better neuromuscular control. In other words, the muscles around the knee functioned in such a way as to prevent knee instability.

The authors suggest that athletes with altered or poor neuromuscular control may be at risk for ACL injury. If the muscle responds too slowly or without enough muscle fibers contracting, injury may occur.

For noncontact injuries, the ligament ruptures when internal forces are greater than the strength of the ligament. In the case of contact injuries, external force (colliding with another person or object) exceeds the tensile strength of the ligament.

Female athletes tend to produce less muscle stiffness compared to male athletes. Women start to contract and use the quadriceps muscle (along the front of the thigh) before the hamstring muscle (along the back of the thigh). The delayed hamstring response to stress on the ACL may be an important factor in the gender differences.

It was expected that more ACL injuries would occur with increasing age. This was not the case in this study. The mid-range age group (35-44 years old) had the highest rate of injuries. Adults older than 44 had the lowest rate of injury.

As this study showed, there are specific patient groups who are more likely to need surgery after ACL. Females and all individuals who had a noncontact injury describe the noncoper group. Age may be an important variable but more study is needed to understand the role of this factor.

Bone marrow edema (BME) of the knee is a painful, but self-limiting disease that can occasionally progress to irreversible osteonecrosis (bone cell death). Currently, other than finding presence of BME through magnetic resonance imaging (MRI), there are no tests for it.

The diagnosis of BME is important in order to be able to treat it properly, according to the type of BME. Ischemic BME, for example, can be treated with core decompression for immediate resolution of pain.

The authors of this study wanted to see if a tapping test, using a reflex hammer, would be a good indicator of the presence of BME in the knee. For the study, researchers assessed 70 patients, average age 51 years. Group 1, 44 patients (46 knees) had BME, while group 2 acted as the control group. They had knee pain but BME was not found through MRI.

The researchers used an ordinary reflex hammer to tap along the knee while the patient reported the severity of the pain using the Visual Analog Scale (VAS), a scale of 0 to 10, with 10 being the worst pain imaginable. X-rays and MRIs were performed before the tapping test, however the physician performing the tapping test was blinded to the x-ray and MRI results.

Results of the tapping showed that patients with BME reported an average VAS of 3.7 (out of 10) in affected areas of the knee and an average of 1.59 in the non-affected parts of the knee. This compared with the control group, which reported a VAS of 0.85 in their painful knees.

The authors note that there were weaknesses in the study, which include that the tap testing was done precisely the same way in all patients, with the aid of a mechanism that supported the mallet and allowed it to strike in the same place on all patients.

In conclusion, the authors write that the test is economical, easy to perform in a doctor’s office, and not time-consuming. While the tapping test has its limitations as to the part of the joint and the type of patients, the authors say that the tapping test is a good screening test for diagnosis of BME in the knee.

Studies show that people with a ruptured ACL are four times more likely to develop osteoarthritis (OA) of the knee compared with those who have a normal, intact ACL. In this article, researchers review the possible reasons why this may happen.

Abnormal motion in the knee joint is seen right away after ACL injury. The term used to describe joint motion in this context is kinematics. It’s possible that abnormal kinematics from ACL deficiency could lead to changes in the way the joint is loaded (or unloaded).

The ACL keeps the tibia (lower leg bone) from sliding too far forward under the femur (thigh bone). Without this restraint, the joint can’t keep proper alignment during motion. The contact points between the two bones can change. And when these two bones don’t mesh just right, some structures can get pinched or rubbed unevenly.

This occurs primarily during weight bearing activities such as walking, jogging, or running. It is especially present for athletes during sports activities. And even when the ACL is repaired, abnormal kinematics puts the person at increased risk of OA.

Over time, abnormal loads or shifts in loads may lead to degenerative changes in the joint. The chondrocytes (cartilage cells) are sensitive to mechanical and biologic changes of this type. But chondrocytes are not able to adapt to these changes when they occur as a result of new loading patterns.

The authors conclude that altered joint motion is the beginning of joint degenerative changes leading to OA. Knowing this helps us understand the need to restore normal kinematics during walking after ACL injury. This study shows that it may be possible to avoid premature OA.

In this study, surgeons combine two new methods of performing a total knee replacement (TKR). A computer-assisted and minimally invasive (MI) approach were both used. They compare the results with patients who have had the standard open incision TKR. Details of both operations were provided.

The patients in both groups were matched in terms of range of motion, strength, and function before surgery. Everyone received the same type of implant. The computer navigation system made it possible to make accurate bone cuts and achieve specific implant position.

X-rays were taken of the operative leg in the weight-bearing position one month after the TKR. Angles of alignment were measured and compared between the two groups. Tests of function were also repeated.

The authors report a much shorter operating time for the standard TKR. The computer-assisted MI approach was an average of 24 minutes longer than the standard method. Function was improved with the computer-assisted MI procedure. Patients in the MI group were walking without assistance 30 days after the operation.

The biggest difference between the two groups was in leg alignment. More patients in the computer-assisted MI group had near normal (neutral) alignment compared with the group who had a standard TKR.

Patients in the computer-assisted MI group advanced faster through the post-operative exercise program. As a result, they went home sooner than the standard TKR group.

Minimally invasive TKR without computer navigation can increase the risk of implant malpositioning. Using a computer to analyze details about the joint can result in improved limb alignment. This increased accuracy also decreases the risk of implant failure from excessive wear, loosening, or instability.

More research is needed to compare groups of patients who have the computer-assisted approach, minimally-invasive approach only, standard TKR, and various combinations of each. Other problems linked with MI TKR, such as poor cement implantation, must still be worked out before this approach is routinely used.