News Category: Knee

Athletes are often surprised when the surgery they had for a torn anterior cruciate ligament (ACL) doesn’t get them back in the game at their preinjury level of participation. That’s why they had the surgery. And that’s what they expected as a final outcome. Physical therapists are asking the question, Could it be because rehab ends too soon?

What is the optimal length of time for rehab after ACL reconstruction? What impairments (physical problems, loss of function) are present to keep the athlete from returning to sports full speed ahead?

In this study, sports physical therapists look at how knee impairments such as loss of motion, decreased strength, and swelling interfere with function after surgery. They also investigate the effect of kinesophobia (fear of movement and/or reinjury) on return-to-sports activities.

Other studies have attempted to look at the association between knee impairments and sports performance. But the authors say that a closer look at those studies reveals too many demographic differences among patients to really make a comparison. Demographics refer to patients’ age, gender, weight and height or body mass index (BMI), general health, time from surgery, and so on.

The patients included in this study had an ACL reconstruction procedure six to 12 months ago. They were all involved in some type of moderate-to-high level recreational or competitive sports before the injury occurred (and before the surgery was done). After surgery, everyone went through a rehab program but not necessarily the same one. The study did not require a uniform rehab protocol.

Impairments such as knee effusion (swelling), joint range of motion, joint laxity (looseness), and muscle strength were measured by highly specialized sports physical therapists. The specific clinical tests and measures for each of these variables was described in detail. All tests were conducted on the surgical as well as the nonsurgical side (for comparison).

The patients also filled out a survey asking them questions about their pain intensity and general quality of life (physical and mental health). They also completed the Tampa Scale of Kinesophobia (TSK-II) to test for fear of movement or reinjury. The higher the score on the TSK, the greater the likelihood of pain-related fear of movement/reinjury.

Patients who interpreted pain to mean they had injured themselves or who were afraid they might injure themselves if they exercised had higher scores on the TSK-II indicating various levels of kinesiophobia. The patients also completed a self-report on knee (physical) function.

A well-known test called the International Knee Documentation Committee (IKDC) subjective form was given. This 10-question test relates knee symptoms with physical function. It is very reliable for assessing function after ACL injury and/or repair or reconstruction.

The surveys and questions were all considered self-report measures. A second category of clinical tests referred to as performance-based measures were also administered. The performance-based test used in this study was a single-legged forward hop test. Standing on one leg, the patient hopped forward as far as possible (always landing on the same leg). Both sides were tested (nonsurgical side first) and compared.

The data was collected and analyzed taking into account all the demographic variables. The results showed that what patients thought they could do and what they could really do were two different things. By self-report, their physical function was much lower than what they could actually do during the physical tests (motion, strength, hop-test). Thus, it appears that self-report versus performance-based assessment can give different results.

In the self-report area, patients perceived that pain intensity and fear of movement limited function. Fear-avoidance behaviors of this type are commonly reported in studies on back pain. Fear-avoidance is considered a psychologic variable.

The concept has been less well studied in knee injuries such as after ACL surgery. The authors suggest that these two areas (pain intensity and fear-avoidance behaviors) would be good targets for rehabilitation. This is especially true for athletes who are not satisfied with function after surgery and want to get back to a preinjury level of activity.

Performance-based testing with the single-legged hop test showed that joint swelling was the main factor preventing a passing score. Strangely enough, the more effusion the patient had, the more likely they were to be able to complete the single-legged hop test. The authors could offer no logical reason for this finding.

Not everyone met the necessary criteria to even take this test. Only 39 of the 58 patients had enough motion and strength to perform the test safely. Patients were more likely to be able to take (and pass) the test 12 months after surgery compared to six months postop.

The authors conclude that this study has identified pain intensity as the main knee impairment and kinesiophobia as a psychologic barrier for some athletes who want to return to full sports participation but don’t. The next step would be to see if it’s possible to predict (ahead of time) which patients will develop participation restrictions.

If a decline in self-report function can be tested early on, it may be possible to develop a rehab program and guidelines for these athletes. It would be aimed at maximizing the number of athletes who get back to full sports participation. They would also look for other (better) ways to assess performance than the hop test. Having both a self-report and performance-based assessment might yield more accurate predictions.

For patients with painful arthritic changes on one side of the knee, a complete and total joint replacement may not be needed. Since 1964, surgeons have been using and perfecting the concept of a unicompartmental knee implant. Results with these devices have continued to improve greatly in the last few years. The reasons for the improved outcomes are explained in this article.

First of all, surgeons have come to understand the importance of patient selection in assuring a successful result for unicompartmental knee arthroplasty (UKA). Adults with unicompartmental (one-sided) knee pain while at rest seem to do best with the UKA. If there are major limitations to motion or significant anatomical deformities, then a total knee replacement is advised.

Patients with osteoarthritis (rather than rheumatoid arthritis) and who are not overweight or obese are the best candidates for a UKA. Studies have shown that being overweight is directly linked with the need for a revision after UKA. And, of course, if there’s arthritic damage to the other side of the joint, the patient should really have a total joint replacement.

Age used to be an important factor. No one under 60 years old would be considered for a UKA. But with improved implant designs and better surgical techniques, the range of acceptable ages has expanded. Younger, more active patients between the ages of 40 and 60 are now considered for this procedure. A few studies have reported patients as young as 35. But there is a concern that the patient will need too many revision surgeries in a lifetime to start so young with even a unicompartmental joint replacement.

There is one other patient factor to consider when choosing patients for a UKA — and that’s the diagnosis. Patients with posttraumatic arthritis don’t do as well as those who have osteoarthritis associated with aging. More studies are needed before firm guidelines can be made regarding this patient characteristic.

The UKA implant also lasts longer with fewer problems when the patient has a normal (intact) anterior cruciate ligament. Without this important restraint, joint deformity develops. There is uneven motion of the bones forming the knee joint as they against each other. Over time, this factor reduces the survival rate of the implant because of increased or uneven wear and then loosening of the implant.

Second, improved surgical technique has been shown to be extremely important. In the early days of UKAs, it was easy to overcorrect a knee deformity and end up with a failed surgery. Getting the right patient, using the most appropriate implant for that individual, and maintaining proper limb alignment are now understood to be a necessary part of the equation for success.

Correct limb alignment refers to the fact that it can be very easy to insert the implant with too much rotation or tilt to one side or another. The surgery can be done with an open incision, which gives the surgeon a better view of the joint and easier time of aligning the implant.

Or it can be done as a minimally invasive procedure with just a three-inch incision. It’s harder for the surgeon to see what he or she is doing with minimally invasive surgery. But the fact that it can be done successfully with less disruption of the surrounding muscles makes the minimally invasive approach very attractive. The stay in the hospital is shorter and the cost is less.

Third, changes have been made in the implant design that have improved results. The polyethylene (plastic) platform that the implant sits on is thinner than it used to be. Finding the right balance of thickness has been a challenge that is yet to be overcome completely. The surgeon aims for correction of any deformities but tries to ere on the side of undercorrection instead of overcorrection.

The slope (or curvature) of the implant has been changed over the years. Surgeons were able to see that an increased slope led to a higher rate of implant loosening. And they’ve discovered that the slope makes a difference when the ACL isn’t present or is damaged. In such cases, an implant with a neutral slope is selected.

Different types of implants have been developed. Some sit right on top of the bone. These are called resurfacing designs. Others require a portion of the bone surface to be removed to make an inset design for the implant.

There’s also the fixed-bearing versus the mobile-bearing implant. This feature describes how much the implant pieces move and rotate against each other. The mobile-bearing unit seems to be winning out. It has a larger area of contact to spread out the load resulting in lower wear rates. Mobile-bearing units are more difficult to get the right balance of knee flexion and extension. This requires a perfect soft-tissue balance to achieve.

The authors conclude that the unicompartmental knee arthroplasty (UKA) has come a long way, baby. In its early days, there were high rates of failure and revision surgeries. Today studies show excellent medium-to-long-term results. There are fewer reoperations, less joint degeneration, more evenly balanced knees, and the possibility of remaining more active.

Choosing the right patient, the optimal implant, and providing the best surgical technique results in shorter hospital stays, more people discharged to home, faster recovery, and improved appearance (smaller incisions). The surgeon can reduce the amount of soft-tissue trauma using a minimally invasive approach — but there is an increased risk of implant malalignment or malposition.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Infection after knee replacement surgery is a well-known risk and one everyone would like to avoid. In this study, surgeons from the Rochester, Minnesota Mayo Clinic get to the bottom of what causes infections serious enough to need surgery to treat them.

They looked at the records of over 17,700 patients to identify 1) how often does this happen (incidence), 2) what happens to these patients (long-term sequelae), and 3) what are the risk factors? They divided cases of infection into three groups of risk factors: patient-specific, surgical, and postoperative.

The goal was to find out what causes minor infections to become major ones later? Early problems reported were usually superficial (on the surface). The problem could be a failure of the incision to close, skin or scar infection, or continued drainage from the wound.

Conservative care was given at first. The wound was cared for and motion was limited that might aggravate the healing wound (including range-of-motion exercises and walking). Antibiotics were prescribed for some patients. Depending on how soon the diagnosis was made and how severe the infection was, the surgeon recommended topical, oral, or intravenous antibiotic therapy.

They found that minor, superficial wounds can progress to become deep infections requiring surgical treatment. This occurred less than one per cent of the time. Incidence (how often it happens) was very low, but still devastating for the patient. They used a 30-day time frame (infection occurred, progressed, and needed surgery within the first 30 days after the knee replacement).

In order to identify specific risk factors, they compared characteristics of the group with infection to the rest of the group who did not develop an infection. What is it that puts some patients at increased risk for infection that other patients without infection don’t have?

Possibilities included body mass index (BMI measured at more than 30), history of previous knee surgery, diabetes, tobacco use, age, gender, and diagnosis. The various diagnoses included inflammatory arthritis, posttraumatic arthritis, and osteoarthritis (most common). Special note was made when patients had other health problems such as circulation problems, heart disease, diabetes, or steroid use.

Only 59 patients out of the more than 17,700 patients developed an infection serious enough to need surgical treatment. That translates to 0.33 per cent (much lower than even the one per cent figure mentioned earlier). Surgery included débridement (cleaning the wound) and/or cutting off the edge of the wound and restitching the skin together. In some cases, more extensive wound repair was done.

There was no obvious difference between the groups in terms of age, gender, or duration of follow-up. Likewise, cigarette smokers and patients who used steroids did not develop serious wound healing problems. And the type of arthritis (inflammatory, posttraumatic, or osteoarthritis) wasn’t a risk factor either.

That left other health problems as a potential risk factor. Looking at each one of those, there were some statistics that suggested peripheral vascular disease (poor circulation to the hands and feet) might have a slight effect. The same was true for body mass index (BMI; slightly more infections occurred when BMI was greater than 30). But the real risk factor was diabetes. Patients with type two diabetes were much more likely to develop poor or delayed wound healing leading to superficial (and later deep) infection.

By following patients for up to five years after the knee replacement, the researchers were able to get an idea of how often deep infections occur as time went one. It turns out that some patients had a deep infection that was missed. The surgeon used clinical judgment that the infection was superficial (when it was really deep), rather than using a specific test (culture of the tissue) to find out if there was a significant infection.

The result of missing deep periprosthetic (around the implant) infections is that a simple treatment early on gets passed by. Eventually, the patient needs much more extensive surgery to take care of the problem. The missed diagnosis increases the risk that the patient could lose the implant. In a few cases, amputation was even necessary.

There were a few things this study did not look at. For example, how can you tell when a superficial wound needs surgical treatment and when can it just be treated conservatively? Secondly, how often does it happen that superficial wounds treated conservatively should have been surgically treated in those early days after surgery? The authors suggest that these two wound healing problems need a closer look in future studies.

Even though only one out of every 300 patients ended up with an infection, the long-term effects were serious. The authors encourage other surgeons to always make sure wound-healing takes place. Any signs of infection should be cultured and treated as soon as possible. Anyone with diabetes should be followed especially closely for early signs of infection or problems with wound healing.

There are some wonderful new ways to treat osteoarthritis in young, active adults. We’re talking adults as young as in their 30s up to early 60s. Up until recently, only older adults were considered for a knee joint replacement. The acceptable age for that has gone down.

Then they came out with a half-knee joint replacement called a unicompartmental knee arthroplasty (UKA). That works well for people with more arthritis on one side of the knee than on the other. Most often, it’s the medial side of the joint (side closest to the other knee) that wears down and develops painful knee arthritis. So the surgeon just replaces that side of the joint with an implant.

But what about patients who are too young or too early in the course of their disease (osteoarthritis) to qualify for a unicompartmental knee arthroplasty (UKA)? What can they do to stay active, participate in sports, or keep up in their jobs when their knee pain limits them? In this report, the results of a high tibial osteotomy (HTO) for this problem are presented.

About 80 patients with medial (inside edge) unicompartmental (one side only) osteoarthritis were treated with this surgical procedure. The patients selected were too young for a unicompartmental knee arthroplasty (UKA). Average age was around 41 years old. Sports and recreational activities were limited by their pain. Conservative (nonoperative) care hadn’t helped. That left the high tibial osteotomy (HTO) as a potential treatment choice.

The patients were examined first arthroscopically. If there was too much damage to the joint or too much of the lateral meniscus (cartilage) missing, then they were not considered a good candidate for the high tibial osteotomy (HTO). The same was true if there wasn’t enough knee flexion or too much knee extension. Other reasons patients might not qualify for this procedure included joint infection, instability (ligament damage), or active joint inflammation from arthritis.

For those people who qualified for the HTO, a wedge-shaped piece of bone was removed from the upper part of the tibia (lower leg bone that forms the bottom half of the knee joint). The remaining two edges of the bone were lined up at in a position of 62 per cent valgus (angled slightly inward). The medial collateral ligament (MCL) along the inside of the knee was partially cut. This step was taken to decrease the amount of pressure placed on the medial side of the knee.

The remaining bone was held together with a metal plate and multiple screws until healing took place. The hole made by removing the pie-shaped piece of bone was not filled in with bone graft. When the body filled in the gap and bone remodeling was complete, then the hardware was removed. This took place around one-year after the initial surgery.

Patients were asked about results through a mailed questionnaire. They answered question about pain, motion, and function. They listed how much pain medication they used during sports activity. And they completed two survey tools to measure activity: the Tegner Activity Scale and the Activity Rating Scale.

Before surgery, the patients reported a major decline in their ability to participate in sports or other recreational activities. Some were unable to resume their desired level of activity after the HTO. But after the operation, they were able to remain as active as they had been just before surgery. Many traded activities. Those who were engaged in jogging or running started walking instead.

Not everyone was satisfied with the results of the procedure. Only 35 per cent (one in three patients) said they were extremely satisfied. About 25 per cent (one in four) said either not satisfied or only partly satisfied with the results. Those few patients (4.5 per cent of the total) who were involved in competitive sports before surgery, did not return to high-level activity or events postoperatively.

Age did not seem to make a difference in how often or how long patients engaged in an activity or sport. Older adults did seem to have greater improvement in function before and after surgery. This group’s pre-operative condition was much more limited than in younger adults so the difference before and after seemed greater.

The authors don’t know exactly why the patients’ activity level was so much less after surgery. They suggested it might be because patients were protecting the knee from further damage. They may have been worried that the repair might not hold up — or that they would end up needing a joint replacement sooner than later.

The benefit of this study was to find out how often patients return to sporting activities after high tibial osteotomy (HTO). Could this be a good middle step between conservative care and a unicompartmental knee replacement? Could it help active, younger adults with the start of painful knee arthritis to stay in the game?

Other studies of HTO have shown a clear shift away from high-impact activities toward lower-impact sports. This wasn’t the case in this study. Participation in most of the top 10 activities remained the same.

As mentioned, there was some modification of activities from running to walking. Some patients had more than the one HTO procedure. That didn’t seem to affect outcomes either. This information will help surgeons know they can make other necessary repairs without fear of affecting the results.

Overall, it looks like the HTO procedure has good results and some excellent advantages. It’s not necessary to cut through the tibialis anterior muscle when doing the procedure like osteotomies done a little lower on the tibia or osteotomies done on the opposite side. There’s less risk of damage to the peroneal nerve. There are fewer problems with shortening of the leg. And best of all, it can improve symptoms and delay total joint replacement by preventing disease progression.

This is the first randomized controlled trial comparing two different treatment approaches for patellar (kneecap) dislocation. Forty patients with dislocation of the kneecap were included. All patients had a traumatic injury either from a military exercise or a sports activity. All of the patients were in the military. Most were men between the ages of 19 and 22.

The real question behind this study was: should a primary (first-time) patellar dislocation be treated right away with surgery? Or can it be managed nonoperatively with a knee orthosis (brace). What are the long-term results of both approaches? There are many surgical ways to stabilize a dislocated patella. In this study, two types of procedures were used based on the type of damage present. Besides a dislocated patella, patients also had an injury to the patellofemoral ligament requiring repair or reconstruction.

The mechanism of dislocation was a sudden displacement of the patella laterally (away from the other knee). The soft tissue structures along the medial side (closest to the other knee) were stretched and disrupted by the force of the pull. Bleeding and swelling into the area was common.

Before the study began, all patients had a knee aspiration done (usually within the first few days after injury). This means that fluid from the swelling was removed with a suction needle. Sometimes aspiration had to be done more than once, especially for patients with massive swelling. Anyone in the study with a loose bone fragment from fracture of the patella had it removed arthroscopically before being assigned to a treatment group.

Everyone was randomly placed in one of two groups: either surgery or bracing. Except for gender, the patient make-up of the two groups was very similar. Surgeons performing the operations could use any surgical technique they thought was best. No one was told to follow a specific surgical protocol. The brace group received a knee brace designed to hold the kneecap in place. This is called a patellar stabilizer.

Patients in both groups followed the same rehab program after their treatment, so that part of their management was the same. The only difference was one of timing: the surgical group began the exercise program 24 to 48 hours after surgery. The orthotic group began their exercise program right away. Exercises were prescribed and supervised by a physical therapist.

The rehab program started with isometric quadriceps exercises. The quadriceps is the large muscle along the front of the thigh. When it contracts, the patella is pulled upwards and the knee straightens. In isometric exercises, the muscle is contracted without actually moving the knee joint. Range-of-motion of the knee was limited to 30-degrees of flexion for the first three weeks. Patients were allowed to bend up to 90-degrees during weeks three through six. After six weeks, the brace could be taken off and the knee could move freely. At that point, a program of strengthening exercises was started.

A variety of different measures were used to compare the results between these two treatments. Patients answered questions and filled out surveys describing and rating their pain, function, activity level, and limitations. Functional activities included things like squatting, jumping, and climbing stairs. These activities are appropriate measures of outcome given that the patient population was a group of soldiers and many of them were involved in competitive athletics.

Knee range-of-motion was measured and size of the quadriceps muscle was compared from the injured side to the uninvolved side. X-rays and MRIs were also taken and compared before and after treatment. Severity of the injury was determined using MRIs. Grades I through IV are given based on how much of the cartilage and bone were damaged. Four areas of knee joint cartilage were assessed (two on each side of the joint).

The main outcome measure was whether the patella dislocated (partially or fully) and whether another operation was needed during the follow-up period. Patients were followed for an average of seven years. What they found was that there were far fewer redislocations in the follow-up period for the surgical group. Nearly one-third of the nonoperative (bracing and exercise) group had a second patellar dislocation. If partial dislocations called patellar subluxation are included, then almost half of the nonoperative group had patellar instability.

The authors concluded that early surgical stabilization and repair of the surrounding damaged soft tissue structures can reduce the risk of redislocation in young, active military recruits. Criteria for surgery used by these surgeons are a traumatic patellar dislocation with medial patellofemoral ligament injury. Type of surgery done depends on the type of injury, presence of fracture or bone fragments, and the natural contours of the patient’s knees. Some patients may have imbalances in the shape and alignment of the patella that should be corrected at the time of surgery.

Patients who injure their knees often need surgery to repair the damage or reconstruct the knee. There could be a fracture or torn ligament(s) that requires immediate surgical attention. In many cases, arthritis develops in that knee and creates another problem later. In this article, two orthopedic surgeons provide a thorough review of what to do when posttraumatic knee arthritis gets worse and requires surgical treatment.

The surgeon has some basic decisions to make about what surgery to do beginning with type of patient. For example, younger patients who are still active can be treated with an osteotomy or arthrodesis (fusion). Older, less active adults with posttraumatic knee arthritis may fare better with an arthroplasty (joint replacement).

Osteotomy refers to the removal of a wedge-shaped piece of bone from one side of the knee. The remaining bone is moved to fill in the area where the wedge was removed. This procedure helps realign the bones and joint and redistribute weight and load.

Each of these procedures for the surgical management of posttraumatic knee arthritis is discussed in detail. The authors present common challenges surgeons face leftover from the surgery for the original injury. X-rays, intraoperative photographs, and drawings are included to show types of cases encountered and surgical management for difficult problems.

Some of the issues surgeons must deal with include broken hardware, scar tissue, stiffness, bony defects, malalignment of the joint, and other bone or joint deformities. Each of these problems must be taken into consideration when planning the treatment approach. The surgeon continues the decision-making process with a careful evaluation of the patient.

Location and quality of pain are noted. Range of motion is measured. The patient’s gait (walking pattern) is examined and analyzed. Tests for knee instability are performed. X-rays are taken to look for limb malalignment, fractures, and status of the hardware. And finally, lab tests are ordered if there is any suspicion of joint infection.

The surgeon takes into consideration the patient’s age, expectations, and goals, along with current activity level and desired activity level. The condition of the knee joint is also a deciding factor in what surgical option is best.

Osteotomy is a corrective procedure. It is used most often in younger adults to unload one side of the joint that is bearing the brunt of the burden. Arthritis affecting just one side of the knee joint is called unilateral or single-compartment degenerative disease. By unloading the side affected by arthritis the most, the knee can be spared much longer. Osteotomy buys the patient time before a total joint is needed.

Patients who benefit from osteotomies usually had a fracture around the knee that resulted in a leg length difference. Malunion or deformity after fracture or ligamentous healing can be treated with an osteotomy. The technique allows the surgeon to restore a more normal mechanical axis (center) of movement while spreading out the forces across the entire joint surface.

Different types of osteotomies can be done from either side of the joint. Determining the best surgical approach for osteotomy requires additional evaluation procedures and preoperative planning. The authors guide surgeons through the steps in making this decision.

There’s an alternate surgical procedure that can be done when osteotomy isn’t enough or isn’t possible in the young patient. That’s an allograft transplantation. Bone from a donor or bone bank is used to replace bone lost. The transplanted bone dies but the body generates new blood to the area and forms its own bone to replace the allograft. Over a period of months to years, the body fills in with its own bone.

When none of these salvage procedures can be done, the surgeon may have to fuse the joint. This is called an arthrodesis. A fusion allows the patient to bear weight and walk on the involved leg. Of course, there are some problems with walking stiff legged. It’s hard to get dressed when you can’t bend your knee. And eventually, the hip and back start to hurt because of the altered biomechanics and movement.

Some patients just aren’t good candidates for a fusion or they don’t want to deal with the hassle of a leg frozen in one position. In those cases, joint replacement may be the best (or only) option left. Older adults with a painful knee and limited motion from progressive degenerative changes may skip right to a total knee replacement (TKR).

Here again, the surgeon is back to facing some of the difficult challenges mentioned before. There may be lots of hardware (plates, screws, pins) in and around the joint from the previous surgery to hold the broken bones together. All of this hardware must be removed without damaging the bone. The surgeon may remove only what’s absolutely necessary and leave the rest in place. These decisions are made on a case-by-case basis.

Along with dealing with hardware is the issue of scarring and incisions. Whenever possible, the surgeon tries to go back into the joint using the previous incision. But there are lots of things to consider in the process. Will disrupting the delicate skin cause more problems? Is there enough blood circulation to the area to make healing possible? Is there enough skin to sew back together after the procedure is finished? The surgeon may consult with a plastic surgeon if the preoperative tissue condition is a concern.

The next challenge to consider is the stiff knee. The surgeon can’t just cut the tendons and joint capsule, go in, and replace the joint. Too much force could cause the brittle soft tissues around the knee to tear or pull away from the bone completely. Sometimes the quadriceps muscle along the front of the thigh is severely contracted. The surgeon must cut through the quadriceps tendon very carefully. The authors present the surgeon with different ways to do this safely, avoiding tiny, but important, blood vessels in the area.

Malunion or nonunion of the original damaging fracture(s) can alter the joint mechanical axis making it impossible to replace the joint. The implant wouldn’t be straight or balanced and uneven wear or loosening could occur. In such cases, it may be possible to perform an osteotomy first to realign the joint before putting in the joint replacement.

But once again, another complicating problem may be present and that’s bone loss. Without enough bone to set the implant into, the surgeon may have to use bone grafts, cement fill, or special screws to manage the problem.

The surgeon may finally get to the place where it’s possible to perform a total knee replacement but the decision-making process isn’t over yet. Now it’s time to choose the right prosthesis (implant).

Because the knee was injured before, even with stabilization and reconstruction, there are usually soft tissue imbalances still remaining. Any ligament imbalances will dictate which implant can be used. The surgeon must assess which ligaments are impaired and choose the implant that will stabilize the knee, support the weight-bearing surface, and minimize stress on the impaired ligament.

When it’s all said and done, the long-term outlook for total knee replacement for traumatic arthritis is fair-to-good. Patients experience a reduction in pain, increased motion, and improved function. The results aren’t always perfect. The postoperative range-of-motion depends on how much motion was there before surgery.

Sometimes the patella (knee cap) doesn’t move up and down like it should. This motion is called patellar tracking and is important for normal knee function. If scar tissue or muscle contracture is preventing normal patellar tracking, then additional surgery may be needed to correct the problem.

Tendon rupture, failure of the wound to heal, and even implant failure are common problems that may be encountered. Patients should be counseled ahead of time what can happen and what to expect. The surgeon can expect and should watch for a high rate of complications after total knee replacement for these posttraumatic arthritis patients.

Infection is one reason why total knee replacements fail or have to be replaced themselves. Surgeons do everything they can to keep this from happening. Looking for risk factors for infection is the focus of this study. The goal is to reduce reoperation rates because of septic failure. Septic failure refers to the breakdown of the area around the infection, in this case the bone and joint.

There are three main groups of risk factors in any surgical procedure: 1) patient-related, 2) surgery-related, and 3) provider- or care-related. Looking at small studies with only a few patients helps bring the problem of infection to our attention. But it’s the large studies that help explain what went wrong. The more patients in the study, the lower the risk of false-negative results. False negative refers to the statistical analysis saying a factor was not significant or important when it really was.

In this study, over 43,000 patients were included. They could gather that many patients into one study because it was conducted at the Finland Hospital for Joint Replacement. In Finland, computer records are kept on every patient who has a total knee replacement. It’s called the Finnish Arthroplasty Register. At the same time, hospitals complete and save records on every person ever discharged. This record is referred to as the Finnish Hospital Discharge Register.

The authors used these two databases combined together to gather data on all reoperations. Reoperation refers to total knee replacements that had to be redone or revised because of infection. By looking at the patients’ characteristics of those who had to have the second operation, they were able to find common risk factors.

It turns out that having a previous knee surgery places patients at an increased risk for infection. Men are more susceptible to this than women. This was true after both the primary and second (revision) surgeries. The reason for this gender difference remains unknown. A prior history of rheumatoid arthritis (as opposed to osteoarthritis) also increased the risk of joint infection. And a previous fracture anywhere around the knee was an additional risk factor.

For primary (first-time) knee replacements, it seems that the type of implant used might make a difference. Patients receiving a constrained or hinged implant were more likely to develop a deep joint infection. The authors suspect the type of implant isn’t really the issue that puts patients at increased risk of infection.

It’s more likely the fact that patients with more advanced joint destruction receive these kinds of implants. It’s the joint damage that puts the patient at increased risk of infection. Once the primary infection has been treated (with a new implant), recurring infection didn’t seem to be related to whether it was a partial or complete revision procedure

Other findings from this study included the fact that patients with poor wound healing were more likely to need a repeat revision (third surgery). The infection rate was calculated based on subgroups of patients. The various subgroups included patients with other illnesses, patients with a cementless prosthesis (implant), patients who had no antiobiotic prevention, and patients who only got the antibiotic cement as a preventive precaution.

What’s the take home message from this kind of study? Surgeons are advised to take preventive measures in any patient who needs a knee joint replacement. The patient should be given intravenous (IV) antiobiotic treatment. The surgeon should also use cement that has an antiobiotic in it to glue the implant in place. These two measures together may help prevent septic failure of the first joint replacement. If infection does occur, the same two preventive steps must be taken when performing a revision surgery.

With more and more older adults (some who are very fragile) getting knee replacements, every effort should be made to prevent joint infection. If infection does occur, a second surgery is often recommended. The surgeon may only need to débride (clear out the pus) the joint and the implant and administer antibiotics. When revision surgery is required, then every effort should be made to prevent reoccurrence of the infection that could then threaten the second implant.

Cartilage injuries in the knee can be a big problem. Healing is very slow, if it happens at all. That’s because the cartilage in the knee doesn’t have much of a blood supply. Getting athletes with a full-thickness (down to the bone) cartilage tear back on their feet and returned to their sport can be a challenge.

That’s why researchers have worked hard to find ways to enhance or speed up cartilage healing. Two techniques developed in the recent past are microfracture and autologous chondrocyte implantation (ACI). Chondrocytes are cartilage cells. In this study from Italy, the results of these two treatment methods are compared.

Microfracture is the drilling of tiny holes in the cartilage to stimulate bleeding and a healing response. Autologous chondrocyte implantation (ACI) is the removal of normal, healthy cartilage cells from the patient. The donor tissue is either removed and expanded (grown) in the lab and then reinjected or it can be harvested from the patient and immediately reinjected directly into the damaged area.

When ACI was first developed, there were some problems. The surgery is complex and the outer layer of the bone (next to the cartilage) often responded by growing too much, a process called periosteal hypertrophy. Some of the results were reportedly controversial.

As a result, surgeons continued to improve the procedure. Now, a second-generation approach has been developed. This means the basic idea stays the same, but scientists have figured out a new and improved way to do it. In this procedure, a manmade scaffold can be placed on top of the defect in the cartilage. This scaffold is three-dimensional (3-D), biodegradable set of polymers. Polymers are plastics or proteins. In this case, the polymers used are proteins. Because it is manmade, it is considered tissue engineered.

Once it is in place, then chondrocytes harvested from the patient’s own healthy cartilage were expanded and placed on the scaffold. The cells were able to make more chondrocyte cells. The final result is a bioengineered tissue called Hyalograft C. The question now is whether or not this new second-generation bioengineered approach is superior to microfracture.

This report shares the five-year results of 40 patients who had the second-generation autologous chondrocyte implantation (Hyalograft C) and compares those results to 40 patients who had the microfracture instead. A five-year follow-up is considered medium-term between short-term and long-term. Outcomes were measured by the presence of symptoms (pain, swelling), knee stability (buckling or giving way), change in knee function, and return to sports.

Patients were not randomly placed in one or the other group. They were treated based on health and insurance policies. The chondral lesions were considered moderate to severe (grade III and IV). They measured from 1.0 cm2 up to 5.0 cm2. Anyone with defects larger or smaller was not included. Patients were between the ages of 16 and 60 and were very active. Most (84 per cent) were well-trained athletes.

Patients were fairly well matched between the two groups (same ages, gender, size of defect). Some of the patients in both groups had a previous knee surgery for some other knee injury (e.g., torn meniscus, ligament rupture, damaged cartilage).

The surgery (either microfracture or implantation) was performed arthroscopically. Anyone with a torn anterior cruciate ligament (ACL) had a repair or reconstruction done at the same time as the microfracture or chondrocyte harvesting. Any instability present was corrected during the surgery. Everyone was treated the same postoperatively and during one-full year of rehab.

No one was allowed to put weight on the healing knee for the first four weeks. Range of motion was allowed along with easy strengthening exercises. The exercises did not put much pressure against the healing area of the joint surface. Weight bearing was introduced and gradually progressed from partial weight to full weight on the leg. Most people were able to put their full weight on the knee at the end of six weeks.

Everyone was followed by a physical therapist who designed and supervised the rehab program. The program was able to help patients regain strength, endurance, and proprioception (joint sense of position). The final goal was to prepare competitive athletes for return to their previous sports activities. No one was allowed to participate in sports any earlier than 10 to 12 months after the surgery.

Patients in both groups had good results with improved symptoms, motion, and function. There was a noted decline in sports activities in the group who had microfracture at the end of five years. The level of sport activity was kept the same from two years to five years after the implantation procedure. Overall, the Hyalograft C group had greater improvements that lasted the full five years compared with the microfracture group. Reoperation and complication rates were equal between the two groups.

The authors concluded that chondrocyte implantation is an effective cartilage repair technique. Any size defect can be repaired this way. The repair site is more stable than with microfracture because of the type of repair tissue that develops. With microfracture, the repair tissue is more likely to be fibrous and unstable.

The second-generation technique is not without its problems. The procedure requires considerable skill on the part of the surgeon. It’s a two-step surgical procedure (harvesting then implantation) and rehab takes a long time. Since most of the patients in this study were young with traumatic cartilage lesions, the authors suggest further studies are needed with older groups who have large degenerative lesions before recommending this procedure for all ages.

Patients with severe damage to the knee cartilage are not without treatment options. One of those is reserved for the repair of full-thickness (down to the bone) chondral (cartilage) injuries caused by acute or repetitive trauma. It is called autologous chondrocyte implantation (ACI) and it was originally designed for patients who had a failed primary (first) procedure.

In autologous chondrocyte implantation (ACI), healthy cartilage cells are harvested from the patient and used to grow more healthy cells to fill in the defect. Most of these patients have had prior treatment with one of the other methods to treat damage to the articular (joint) cartilage. Such surgical repair procedures include debridement, microfracture, drilling or abrasion, or osteochondral grafting.

In this study, 154 patients with failed results from their first treatment for articular cartilage defects received an autologous chondrocyte implantation (ACI). The work was done by dozens of surgeons at multiple different centers around the United States and Canada. The goal was to examine three things: effectiveness, safety, and durability of ACI for these patients.

A previous failedsurgery meant that the patient still had significant pain and loss of function. Patients were eligible for this rescue procedure if they were: 1) at least 18 years old, 2) had a previous (now failed) surgery within the last three years, and 3) fair-to-poor score on a knee rating scale (the Modified Cincinnati Knee Rating System). The knee rating scale was an indication of overall knee condition.

There were certain restrictions on who could be chosen for the implantation procedure. They could not have had 1) a previous ACI treatment on the same knee, 2) removal of the meniscus (meniscectomy), or 3) knee arthritis (osteoarthritis or rheumatoid arthritis).

Results of the ACI treatment were measured in two ways: benefit to the patient and differences in the patients. Benefit to the patient included knee pain, knee function, quality of life, and overall health. It was also noted how long the benefits lasted (duration).

At the same time, the researchers were looking for differences in patients. Were there reasons why the first procedure failed in this group of patients? Was there some characteristic that could explain the failures? Would it be possible to screen patients ahead of time looking for a particular factor or group of factors that might predict failure, and thus prevent it from happening?

A two-stage chondrocyte implantation method was used. In the first procedure, the normal, healthy cells were removed from the patient. They were sent to a lab where scientists used them to grow even more cells. This process is called expansion. Once there were enough cells and they had been tested for viability (meaning they are alive and have the potential to stimulate cartilage growth in the defect), then they were placed in the cartilage lesion.

After that, everyone was followed for at least four years. Patient characteristics compared between the failed ACI group and the successful group included age, gender, body mass index (BMI), and level of knee pain and function. They also looked at overall knee condition, number of cartilage lesions, lesion size, and lesion location.

Three-fourths of the patients had a successful outcome. One-fourth experienced failure defined as no improvement in symptoms after three months of rehab and/or the need for retreatment of the cartilage defect after ACI. Using data collected from the patients with a failed ACI procedure, they were able to calculate the time to failure, which could be used as part of the prognosis (i.e., what to expect after surgery).

In the statistical analysis of the data collected, the authors were able to predict the probability of ACI success after the first (non-ACI) procedure failed. From this information, they were also able to make predictions about the expected durability of the ACI as second-line therapy. This type of information helps the surgeon give the patient a reasonable prognosis.

All of that was geared toward evaluating the effectiveness of the procedure. Then they turned their attention to the safety of ACI. Of course, a failed surgery was considered a serious adverse event. Other complications such as infection, delayed healing, hypertrophy (graft overgrowth), and joint adhesions were assessed as mild, moderate, or severe.

About half of the group had at least one problem following the ACI procedure. Usually, this was overgrowth of the bone around the implant. Most adverse effects occurred within the first two years. The presence of adverse events after ACI did NOT necessarily mean the patient would have a failed response eventually.

And in the last analysis performed, the time to failure (TTF) or durability was reviewed. They found that when failure occurred, it didn’t happen until after the study ended at 48 months (four years). Comparing these results with non-ACI treatment, the ACI procedure outlasted the non-ACI approach by at least 31 months.

Looking back at the patient records, they checked to see if having one type of first (non-ACI) procedure over another made any difference. In other words, did the patients who had a marrow-stimulating procedure do better than patients who had debridement (removing fragments of tissue)? The answer was no. Both groups had an equal number of failures and successes.

The authors concluded that the results of their study agree with other studies done on the same topic. Patients with moderate-to-large chondral lesions who did not improve with non-ACI treatment can go on to have a good result with an ACI as a second procedure. This opens up the treatment possibilities for patients with poor knee function after a failed cartilage first procedure for full-thickness chondral injuries.

The improvements in this group of patients were significant and long lasting. Most of the patients had no problems with daily activities and could even participate in sports with no (or very few) limitations. The true durability of ACI repair isn’t really known, since this study ended at 48 months. The authors suggest further studies to gain a better understanding of the long-term durability of ACI repairs.

Should a knee immobilizer or some other type of brace be worn after ACL repair? This is a question that remains unanswered despite many studies on the topic. Maybe only certain patients need immobilization. But is that’s the case, then who should it be? And what kind of knee brace should be worn?

One way to get to the bottom of this issue is to study one aspect of the problem at a time. In this study, the authors specifically look at the effect of a soft, unhinged brace or immobilizer on knee pain. The effect of wearing the immobilizer versus no immobilizer was measured based on patients’ reports of pain.

The immobilizer is different from a hinged brace. The immobilizer is a one-piece, soft, wrap-around piece of foam-lined canvas. It has three vertical metal bars for support and is strapped on with Velcro®. A hinged brace is sometimes called a functional brace. It allows joint motion in flexion (bending) and extension (straightening). It is made of stiffer material than the immobilizer and has thin metal bars on either side of the knee to allow joint movement but prevent rotation.

Functional bracing is used to provide a derotation (prevents rotation) force. It is believed that this type of protection is needed during activities that require planting the foot on the ground and pivoting (twisting or turning while changing directions). The soft knee immobilizer just limits knee range-of-motion. It doesn’t allow for functional movement.

Two groups of patients were compared. All patients were between the ages of 18 and 40 and had an ACL repair using a hamstring tendon graft. One group wore the soft immobilizer continuously during the first two weeks post-operatively. Patients were allowed to remove the immobilizer only for bathing and to perform their exercises. The other group did not get an immobilizer or brace of any kind. Everyone in both groups followed the same rehab program for the first two weeks post-op.

Pain level along with amount of pain medications used was measured for 14 days. The patients kept a daily logbook to record their pain levels and analgesic (pain relievers) use. Type of pain reliever and amount used were also recorded. Any complications that occurred were noted. Knee range-of-motion was recorded for the first three weeks after surgery.

The main measure used to evaluate the use of an immobilizer was pain during the first two days after surgery. The reason they used this as the key factor was because surgeons reported pain control as the primary reason for using a knee immobilizer. No one really knows whether or not the immobilizer is needed or if it even helps with pain.

In the end, it turned out that there were no differences in outcomes between the two groups. Patients in both groups had the same pain levels, used the same amount of pain relievers, and regained motion in the same amount at the same time. The researchers then took a look at the patients’ characteristics to see if there were any differences in age, gender, or type of anesthetic used. It turns out that there were no statistically significant differences among those variables either.

Taking a closer look at the pain patterns (based on medication use), most of the pain relievers were taken on the first day. That was true for all patients in both groups. And the most common drug used was an antiemetic for nausea and vomiting, not for pain relief.

In general, complications were minimal and equal between the two groups. There were reports of skin numbness, wound scabbing, and knee joint swelling. Patient compliance was also reviewed. Overall, patients wore the brace as directed 76 to 100 per cent of the time. Everyone was very diligent to wear the immobilizer during the first two days. But entries in the logbook made it clear that compliance decreased over time. By the end of the study, only about one-quarter of the group wore the immobilizer more than 75 per cent of the time.

Some patients didn’t like wearing the brace because it slid down or was uncomfortable. A few reported it was inconvenient putting it on and taking it off. At the same time, there were patients in the nonimmobilized group who wished they could wear a brace to protect their knees.

Based on the evidence from this study, the authors could not recommend an unhinged knee immobilizer for ACL repairs with a hamstring graft. It’s possible that some other type of immobilization would be more effective. Perhaps using a hinged knee brace would appeal to patients more and improve compliance. The authors suggest trying a hinged knee brace next time. Patients could lock it at night to protect joint motion and wear it hinged during the day to allow motion.

Over 35 years have passed since the first report of anterior cruciate ligament (ACL) knee injuries in military recruits. In those days, arthrotomy (open incision) and repair of the torn ligament was attempted. The first study and report of results was published in 1976. In this follow-up study, long-term patient results are reported for those same patients.

Since those early days, surgeons discovered that ACL reconstruction is much more successful than ACL repair. Instead of reattaching the torn tendon, tendon material is taken from either the patellar tendon or the hamstrings and used to replace the damaged ACL. So, although today’s patients aren’t likely to have the same procedure as those original West Point Cadets, the long-term results are still important. They can be used to compare to long-term results from techniques currently used to restore ACL function.

Arthroscopy is used for most ACL procedures today. This minimally invasive procedure has reduced many of the complications associated with open repairs. Many of the circumstances around the surgery are different today. It’s no longer an in-patient procedure with long pre-surgery and postoperative hospitalizations. In the 1970s (before arthroscopy), even partial ACL tears were diagnosed with arthrotomy.

One of the other major differences in the treatment of ACL ruptures then and now is the post-operative care. Back then, patients were placed in a long leg cast for six weeks. Today, some patients don’t even use a brace and can put weight on the leg right away (as tolerated).

As a means of measuring results over time, each of the former military cadets was interviewed about their motion, pain, function, and satisfaction with the open repair they had years ago. Five years after the first surgery, cadets were asked, If your knee was 100 per cent before injury, what would you rate it now?. It turns out that the outcomes of that first five-year study were predictive of the long-term results. Cadets who gave their knee a poor rating at that time, were more likely to end up with an unstable knee 30 years later. And in this study, more than half ended up with a poor result.

Some patients may have had a worse outcome than reported. As activity levels declined over the years, the patients were less likely to complain they were unsatisfied with the results. It may be a gradual adjustment to loss of function as well the aging factor.

The authors suggested (based on evidence from other studies) that our understanding of ACL injuries today help explain the poor outcomes of the West Point cadets. We know that younger patients (under the age of 22) seem to fare the worst after ACL reconstruction. Most of the injured cadets were around 20 years old.

Ligament rupture close to the bone has a better chance of recovery. Most of the cadets had midsubstance (middle of the ligament) tears. And football injuries have the worst results (skiing injuries seem to recover the best). A large number of the West Point injuries were noncontact football injuries.

Using the data from this study, the authors confirm what other studies have shown — that the condition of the knee meniscus at the time of the ACL repair is important. Patients with meniscal injuries along with ACL tears have lower long-term outcomes.

As this historical study has shown, much has changed in the treatment of ACL injuries. Reconstruction rather than repair has resulted in much more positive outcomes. Arthroscopy has made early diagnosis and intervention possible. And the diagnosis is more accurate and reconstruction easier. Having newer clinical tests and MRIs available has also helped in the diagnostic process.

When a patient presents to his or her general practitioner (GP) with a knee injury, the doctor relies on the patient’s history (what happened) and a physical exam (clinical tests) to figure out what’s wrong. Is there swelling in the joint? Is there damage inside the joint? Can a physician even tell these things with a history and physical exam (H&PE)? When are additional tests such as X-rays or MRIs needed?

Researchers from the Netherlands take on these questions in a study of 134 patients with a traumatic knee injury. Most (but not all) injuries were sports-related. Each patient was questioned about their symptoms and then examined by a physical therapist using a standard series of tests for the knee. Tests included range-of-motion, palpation, stability, and meniscal (knee cartilage) tests.

Three special tests were done to look for effusion (swelling). The first was palpation of the popliteal fossa (back of the knee). The second was a palpatory test called the minor effusion test. The examiner pushes the fluid in the knee from one side to the other. And the third test of effusion was the Ballottement test. The examiner presses the patella (kneecap) down (the patient’s leg is extended or straight during the test). When there is swelling under the patella, the kneecap moves down, clicks as it touches the bone, and then floats back up.

How accurate are these tests? Can a general practitioner rely on them to make the diagnosis? Are all three tests required? Or is there one test that’s better than the others to detect damage inside the knee? One way to answer these questions is to test each patient, take an MRI, and then compare the results between the two tests. The MRI is a very accurate test for effusion of the knee.

Analysis of the data showed that three-fourths of the patients with moderate to severe effusion had a serious knee injury as shown by the MRI. The injury was either a torn ligament inside the knee or damage to the meniscus (cartilage). In 62 per cent of the cases, it was possible to tell there was joint effusion using the ballottement test. And they noted that when effusion was present, damage inside the knee was likely.

There were a few yes, but messages from the study. For example, the authors pointed out that it is possible to have a knee injury without swelling. It’s also possible that swelling might be present but the tests used here would still be negative.

In the end, it looks like a positive patient report (the patient thinks the knee is swollen) combined with a positive ballottement test is highly indicative of damage inside the knee. Combining results of the history and physical exam is a reliable way to assess knee effusion after a knee injury. X-rays are taken if the physician suspects bone fracture. Conservative (nonoperative) care is recommended otherwise. MRIs are suggested when there is doubt about the diagnosis.

Referral to an orthopedic surgeon is advised if there is clicking of the knee and/or the general practitioner has reason to believe there is internal derangement of the knee such as a ligament or meniscal tear.

Little by little, total knee implants have been improved over the years. But it hasn’t happened by magic. Makers of the implants sponsor studies like this one to evaluate what works, what doesn’t, and what changes are needed to improve the results. Better quality of life and longer lasting implants are two main goals with total knee replacements (TKRs).

In this study, 116 surgeons in 34 centers in the United Kingdom performed total knee replacements on over 2350 patients. Three specific design features were the focus of attention: 1) metal backing on the tibial portion of the implant, 2) patella resurfacing, and 3) a metal bearing between the tibia (lower leg bone) and the femur (thighbone).

Surgeons and patients were selected carefully. In the case of the surgeons, only those who routinely did knee replacements were part of the trial. Each patient received one of the three components being studied. Anyone who needed a particular type of replacement for any reason received the required implant and was not included in this study.

What did they know about these components before heading into this study? Metal backing spreads the load out and reduces overall stress on the implant. But it takes up space in the joint. And there is also a polyethylene (plastic) lining for the new joint surface. So when there’s a metal backing, the lining has to be thinner.

A thinner lining puts more pressure and shear force on the weight-bearing surface of the new joint. But there haven’t been any studies comparing metal-backed with nonmetal-backed implants to see if there’s a difference in performance.

Patellar resurfacing involves placing a smooth metal surface on the back of the patella (knee cap). This feature allows for smooth motion of the patella as it glides over the femur. No studies have been done to show the benefits of this feature.

And finally, the third design studied was the mobile bearing. This rotating-platform between the tibial and femoral components is supposed to reduce polyethylene wear and shearing that occur between the implant and the bone. The hope is that the bearing will help prevent loosening of the implant. But there have been reports that the bearing dislocates.

Each of these design features was compared between two groups of total knee replacement patients. One group received the particular component. The other group did not. Surgeons performed the procedures according to their own standard methods. Outcomes were measured in terms of cost, effectiveness, complications, function, and quality of life. The study had a follow-up period of two years.

There were many findings from the study such as complication rate (equal among all groups), operative time (longer in the metal backed group), and hospitalization (average was nine days for all groups). In addition, 95 per cent of all patients went home directly from the hospital. Pain was reduced and function improved within the first three months. Gradual improvement continued after that initial recovery period.

But the bottom-line was that the overall results were the same from group to group. Everyone improved equally by the end of two years. Rates of complications during that time were the same and functional recovery was no different from group to group. Outcomes were measured according to results important to the patients (not the surgeons). The results are all considered short-term, so patients will be followed for another eight years for a better look at long-term effects.

The authors could not recommend one total knee replacement design over another from the results of this one study. But the hope is that with long-term results, patterns of design wear and the pros and cons of each will be more obvious. The wide range of centers and surgical techniques may have some effects on the results. These factors will be taken into consideration over time as well.

You may have heard the old expression Looks can be deceiving and that’s the case with partial tears of the anterior cruciate ligament (ACL). The ACL is one of two very strong ligaments that hold the knee together and provide stability as the tibia (lower leg bone) moves under the femur (thighbone). Damage to either of the two bundles that make up this ligament can result in loss of stability and function of the knee.

In this article, two orthopedic surgeons review partial ACL tears. They explain why it’s so difficult for surgeons to tell if the ligament is intact (okay) or not. Sometimes, a partially torn ligament looks perfectly fine. But it’s really damaged and over time, it starts to lengthen or stretch out. Ligaments don’t really stretch and bounce back like a rubber band. They are more likely to stretch and stay stretched out. And without a strong connection to hold the bones together, the tibia slides around too much under the femur.

Sometimes a partially torn ACL can be treated conservatively with nonoperative methods such as antiinflammatories and an exercise or rehab program. The surgeon’s task is to determine which patients can be treated this way and who needs surgery to repair or reconstruct the ligament.

Making the right decision is important because ligaments don’t have much of a blood supply. That means self-repair of a partial tear is not possible. Under the right conditions, it will eventually tear completely. Avoiding such an injury is often the goal, especially with athletes who are trying to stay in the game despite a partial tear.

How does the surgeon accurately diagnose the problem? That can be a problem in itself. When clinical tests commonly used by examiners are positive (e.g., Lachman test, pivot-shift test), then it’s clear that there is an ACL tear. But studies show that these hands-on tests can appear normal when up to 75 per cent of the ligament is torn.

Several other diagnostic tests are available when the surgeon suspects a partial ACL tear. The first is the KT-1000 arthrometer test. This test provides a measure of joint laxity or looseness. Some people have naturally loose ligaments, so the injured knee is always compared to the uninjured side. More than three millimeters of difference from side-to-side is a red flag sign of pathologic injury. But once again, this test can fool the clinician. It simply isn’t always a sensitive enough test. Results of the test can appear normal when there is a partial ACL tear.

Some suggest relying on MRIs for the diagnosis. But even with today’s more advanced MRI systems, up to half (or more) of the partial ruptures will be missed using MRIs. A more reliable (but still not always 100 per cent accurate) method of identifying partial ACL tears is the arthroscopic exam.

Even with a scope inside the joint, if the outer covering of the ligament is intact, the surgeon won’t see the torn fibers inside the sheath. And sometimes scar tissue mimics a normal appearing ligament support structure. Surgeons are advised to perform the pivot-shift test under anesthesia when the ligament appears to be torn.

In this way, the effects of muscle spasm and guarding are eliminated and the results are more accurate. Studies show that the pivot-shift test is only 24 per cent sensitive when the patient is awake compared to 92 per cent sensitive when under anesthesia. Results of the pivot-shift test while in the operating room can be misleading if there is other soft tissue damage inside the joint. The surgeon must take the opportunity to double-check for problems such as cartilage, bone, or meniscal fragments in the joint.

If the pivot-shift test is truly negative, the ligament is not functionally deficient. In other words, even though the ligament is partially torn, it can still function to some extent. Those are the patients who can do well with a rehab program instead of surgery. A nonoperative course of treatment is especially indicated if the individual isn’t very active and/or doesn’t have much in the way of symptoms.

Surgery is advised for anyone with high levels of activity that place heavy demands on the knee. There are several surgical options for managing partial ACL tears. These include various methods of repair or reconstruction of the ligament. Reconstruction is favored over simply repairing the tear. This assures the patient will have a stable knee that will support him or her in returning to sports activity at a preinjury level.

The use of thermal energy such as lasers and radiofrequency is not advised at this time. There’s some concern that heat treatment of this type decreases the stiffness of the collagen cells that make up the ligament fibers.

The authors comment that every case requires an individual approach. There are so many possible factors that can interfere with an accurate diagnosis and/or with selecting the best treatment. How long has it been since the injury? What are the patient’s expectations about recovery and return to sports participation? Is there any damage to the other soft tissue structures of the knee to consider? Has the patient already tried (and failed) nonoperative care?

No one really knows the natural history of partial ACL tears. Natural history refers to what happens if the injury isn’t treated directly in any way. That’s a tough one to figure out because some patients don’t give the injury time to recover. They end up reinjurying the same knee with continued high-level sports participation.

Maybe it’s the case that partial tears will always progress to complete tears. Maybe partial tears only become complete tears when more than 50 per cent or 75 per cent of the ligament is torn. Perhaps the patient’s age makes a difference. These are all the factors we just don’t know a lot about. There have been some studies in this area, but the results varied enough that a conclusion could not be reached.

For now, the authors provide an in-depth and insightful review of every aspect of the partial ACL tear. Anyone interested in understanding more about this condition is advised to read the details in this article.

The winds of change have affected medicine — how it’s practiced and how results are measured. In this report, Dr. R. W. Wright, Associate Professor and Director of the Orthopedic Residency Program from Washington University in St. Louis focuses on how this has affected the treatment of knee injuries.

The first shift has come with a change from clinician-based measures of results more to a patient-reported outcomes base. This has meant a change in the tools doctors and other clinicians treating knee injuries use to measure change. Dr. Wright presents nine different outcomes measures for assessing patients with knee injury. Some are joint-specific, some address general health, and others are disease-specific. Disease-specific refers to a focus on one type of injury, such as an anterior cruciate ligament (ACL) injury.

With the rising cost of health care, using some type of measure to assess the effect of treatment is essential. Health care professionals are being asked to explain and justify health care dollars being spent on patients. Tools to measure patient outcomes must be geared toward patients and their specific diagnosis in order to guide future management programs.

Some of the instruments used today with knee injuries include the Short-Form-36 (SF-36), a measure of general health, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), specific to osteoarthritis of the lower extremity, and the Knee Injury and Osteoarthritis Outcome Score (KOOS), geared toward sports injuries.

Other knee specific (mostly focused on ligaments) include the International Knee Documentation Committee Subjective Form (IKDC), Lysholm Knee Scale, Cincinnati Knee Rating Scale, and the Anterior Cruciate Ligament Quality of Life (ACL QOL) score.

Each of these scales measure various aspects of physical functioning, emotional well-being, pain (and other symptoms), limp, work-related concerns, and sports participation. Sometimes specific activities such as running, cutting, decelerating, and pivoting are assessed. Just as important are measures for social functioning, emotional vitality, and quality of life.

Greater recognition is given these days to the importance of patient satisfaction. Patient-reported outcomes are certainly subjective (based on the patient’s assessment). This is a shift from the measurements clinicians have always relied upon (e.g., range of motion, strength, motor control).

This is a reflection of the fact that sometimes objective measures of strength show improvement, but the patient’s function doesn’t improve or the patient isn’t happy with the results. If a patient improves enough to return to school or work but not enough to return to sports or recreational activities, is that good enough? And by whose standards? In other words, who sets the bar for acceptable results — the surgeon, the patient, or the health insurers?

The author suggests that separate measures are needed for separate areas. That’s why knowing about multiple tools to assess outcomes is necessary and important. At the very least, the clinician should use a general health survey and a second scale to measure specific results of the disease, injury, or condition.

When choosing the right assessment tool, the surgeon or other health care clinician must keep in mind several factors. Is it relevant to the patient? Is it reliable and valid? Is it easy to administer, score, and interpret? Is it responsive? In other words, can it detect a change (improvement, decline) when it occurs?

With dozens and dozens of tests available, it may be best to stick with the more commonly used, researched, and recognized scales presented in this review article. Advantages and disadvantages of each scale are presented, along with suggestions for scale selection.

For example, it may be helpful to match the patient’s goals with scales that provide a way to tell whether or not the goal(s) have been met. A different tool may be used with athletes who have higher expectations than an older adult who just wants to be able to walk again.

The concern over late complications such as osteoarthritis suggests the need to conduct a baseline exam and repeat measures during follow-up. The author suggests that all patients with ACL injuries should complete some type of joint specific and activity rating scale. The Tegner Activity Level Scale and the Marx Activity Level Scale may work best for this. The Marx Activity Level Scale is also useful for nonathletes as it measures function rather than sports activity.

The changes that are occurring in measuring the results of treatment for knee injuries are placing more of an emphasis on global (overall) assessment. Scales used can assess both recovery from the knee injury and effect of specific treatments applied. Including patient quality of life and satisfaction in the evaluation process rounds out the results. All of these measures should be used to justify treatment selected or to modify treatment when expected results are not forthcoming.

Highly active people who injure their anterior cruciate ligament (ACL) in the knee are often faced with an important treatment decision: surgery or no surgery? Wouldn’t it be great if there was a test that people could take to help them answer this question?

What we need is a way to tell who is a good candidate for nonoperative care and who should just go ahead and have the surgery. In fact, such a tool may be here. Researchers at the University of Delaware have put together clinical guidelines using a screening exam that might just do the trick.

At least their results (72 per cent success rate) was much higher than in other studies where patients decided for themselves not to have surgery. Their work will have to be repeated by others to validate their findings. But for now, they report an increased ability to return highly active adults to their preinjury level of activity safely and effectively without surgery.

The results of this study are important because there’s been an increasing trend to perform surgery early for people who want to get back to their high-demand activities. There’s a belief that the risk of further injury and/or damage to the joint is too great to wait.

But other studies of long-term results following ACL repair or reconstruction aren’t always so good either. And there are people who do, in fact, get back to high-level activity without surgery and without a recurrence of the problem — no symptoms, no instability, no recurrence or reinjury.

So, what does this screening exam and treatment decision tree look like? First, it’s based on more than 10 years’ worth of study, clinical trials, and careful evaluation. Second, the athletes included were those who put in more than 50 hours each year of high-demand activities such as jumping, cutting, pivoting, or lateral movements.

Third, each athlete was examined for other injuries that might keep them from trying a conservative approach. For example, a ruptured ACL along with damage to other knee ligaments or injury to the other knee, the meniscus, or joint cartilage makes the person a poor candidate for nonoperative care. Likewise, fractures, dislocations, back injuries, or nerve injuries also put the patient at increased risk for a poor result with conservative care.

If the patient had the time and inclination to do so, he or she could try conservative care for any of these other injuries first. If successful, then they could come back and go through the screening process to decide what to do about the ACL injury. Before qualifying for the screening exam, the injured athlete had to meet the following criteria:

Over the years, surgical technique for the repair of a ruptured or deficient anterior cruciate ligament (ACL) has evolved and changed. Most recently, in the 1990s, surgeons went from using a two-incision tunnel to a one-incision technique. Results of each method have been studied and are now compiled in this report.

The incisions made to create tunnels through the bone through which the graft tissue is threaded is a reflection of the location of the graft placement. And graft placement appears to be an important factor in the success of ACL repairs (single or double). The graft must be able to resist tibial translation (movement of the lower leg bone against the femur or thigh bone). It must also resist abnormal internal tibial rotation.

When combined together, too much of these two motions (tibial translation and internal rotation) are what result in something called the pivot-shift phenomenon. The athlete plants his or foot on the ground and attempts to make a sudden shift or move in another direction. With an unstable knee, the joint buckles or gives way underneath the athlete.

Health care professionals in the sports world use a clinical test called the pivot-shift that tests for this type of stability/instability. A positive pivot-shift test means there’s too much movement at the joint. It’s a sign of a failed ACL repair.

The repair can be done as a single bundle approach or a double-bundle procedure. Just as the term indicates, single-bundle is a piece of tendon taken from elsewhere around the knee (usually patellar tendon or hamstrings) and used to replace the deficient ACL. A double-bundle graft is more likely made from hamstring material. The double-bundle is formed by folding the graft over to form two layers of graft material.

The double-bundle graft was developed to provide greater stability. It was felt that a single-bundle graft led to too many failures as measured by a positive pivot-shift response. But the double-bundle graft is complex and requires two grafts and two femoral and tibial tunnels. There’s been some question about the failure rate for this approach compared with the single-bundle method.

To help put the debate to rest, a well-known orthopedic surgeon (Frank Noyes, MD) and the author of this article reviewed the available literature and compared the results between these two procedures. He looked at studies using cadavers (human knees preserved after death for study) and live humans.

Cadaver studies are helpful because the ACL can be cut a little at a time to see what effect that has on knee stability. The same thing can be done progressively sectioning (cutting) other ligaments and soft tissues in and around the knee. This is done to help mimic conditions in an injured knee that has more than just the ACL damaged.

In cadaver studies, different parts of the ACL can be sectioned in different places. This shows the function and value of each portion of the ligament complex. And the validity of clinical tests can be verified using cadavers.

These tests (like the pivot-shift test) are commonly used by surgeons, physical therapists, and athletic trainers to assess the damage to each ligament and soft tissue structure. For example, it’s possible to see how much damage must be done to each individual structure before the pivot-shift test is positive.

Dr. Noyes provides a detailed account of the type of drilling techniques, placement of the graft attachment, and effect these have on results. A review of the anatomy of the intact knee compared with the knee orientation after single- and double-bundle grafts is also offered. He reports on the amount of tibial translation that occurs in cadaver studies with progressive sectioning of the ACL and other knee ligaments (e.g., posterior cruciate ligament).

No one really expects grafts to restore normal motion and provide perfect check-reins on abnormal motions. The natural, normal ligaments’ design and fiber tension behavior are simply too complex for that. But the graft can provide enough tension to protect the knee from instability and restore normal function. This can be done without limiting normal tibial motion too much, a situation called overstraining.

It has been noted that a vertically oriented single-bundle ACL graft resulted in many more patients with a positive pivot-shift test (compared with patients who got the double-bundle graft). But there were other studies where there wasn’t much difference in results between these two procedures. So, some authors advocated the simpler, less complex single-bundle procedure. Why go to all the trouble of using the double-bundle technique when the single-bundle works just as well and isn’t such a technically demanding operation?

In looking back at all of the studies (cadaveric and human), Dr. Noyes could not support one method over another. There are different advantages and disadvantages to each. It appears that the location of the graft may be a key factor in results.

In some cases the orientation of a single-bundle graft can give the same stability provided by a double-bundle graft. The next step seems to be studies to compare locations of single-bundle grafts. The goal would be to find a single-bundle orientation that offers all of the advantages of a double-bundle approach without the complexities of technique.

In this report from Australia, the results of surgical treatment for proximal hamstring syndrome are discussed. The sciatic nerve is released from the hamstring muscle where the two have become tethered or attached by adhesions or scar tissue. Proximal refers to the upper portion of the hamstring muscle where it attaches to the ischial tuberosity (the part of the pelvic bone that we sit on).

The hamstring syndrome was first discussed in the late 1980s. Athletes involved in many different types of sports have experienced the pain, tenderness, and weakness that occur with this syndrome. At first it was only called hamstring syndrome. But the current authors have renamed it proximal hamstring syndrome to indicate a more precise location of the problem.

The condition must be differentiated from several other possible causes of buttock and leg pain (e.g., sciatica, piriformis syndrome, hamstring muscle tear). The surgeon takes a careful history and performs an exam to make the diagnosis. The patient may report a specific (hamstring) injury that led to the start of this problem. Or the symptoms may have developed slowly over time creating a chronic problem of hamstring tears with scarring and eventual tethering.

Usually, the pain pattern of proximal muscle syndrome is slightly different from these other conditions. There is pain in the buttock that goes down the leg toward the back of the knee. When the examiner presses on the ischial tuberosity, it reproduces the pain or is tender.

Sitting or stretching the hamstrings also brings on the painful symptoms. This pattern is different from a hamstring tear where the pain is more in the muscle belly or the piriformis syndrome where the tenderness is deep in the buttock muscles. Weakness of the hamstring muscle is also common with proximal hamstring syndrome. The athlete is unable to run at full speed — or even increase the pace in that direction.

Nerve conduction tests were not always helpful. The results were just as likely to be positive or negative in patients with proximal hamstring syndrome. A better test was performed with the patients prone (face down). Strength of the hamstring muscle was tested with the knee bent to 30 degrees and compared with the same strength test at 90 degrees. Severe weakness with the knee flexed at 30 degrees (compared with normal strength at 90 degrees) was a good test for this problem.

The authors developed a surgical protocol for these patients. The senior author spent 10 years reviewing patient records. He looked back at the presenting symptoms, what treatment worked the best, and the results of this surgery. Patients involved were all ages from 15 to 58. They were all involved in competitive sports, some even professionally.

Everyone was treated first with conservative (nonoperative) care. Treatment varied from patient to patient but included nonsteroidal antiinflammatory medications, steroid injections, chiropractic, physical therapy, and/or acupuncture. When the thigh pain and weakness did not improve, then surgery was indicated.

The authors described the surgery performed. Patient position, surgical technique, and ways to prevent complications are discussed. The sciatic nerve was carefully cut away from the hamstrings. Scar tissue and any areas of obvious tendon scarring or degeneration were removed.

Follow-up included a short rehab program to restore motion and strength. Patients were interviewed by questionnaire during the subsequent follow-up. They were asked about pain, strength, return-to-sports, and satisfaction with the results.

Pain relief was reported by most (but not all) patients. Strength improved to normal or near normal in 25 of the total 35 patients. The remaining 10 had no change or reported increased weakness. Three-fourths of the patients were able to return to competitive sports action.

Pain and weakness prevented three players from returning to the sport of their choice. The patients who were able to return to sports participation were very satisfied with the results of the surgery. One-third of the group was perfectly satisfied, giving top scores on the survey to indicate their response to the outcomes.

The authors conclude that proximal hamstring syndrome that does not respond well to conservative care can be effectively treated surgically. At least six months of nonoperative care is advised before considering surgery. Severe pain and weakness that interfere with function are the main reasons patients choose surgery.

The authors also warned that surgeons must approach this problem carefully. It’s easy to misdiagnose. Surgical treatment can result in complications such as wound infection or nerve injury. The sciatic nerve must be released very carefully. The nearby posterior femoral cutaneous nerve must not be disturbed or traumatized in any way. Patients must be prepared ahead of time for the possibility of a poor or failed result.

Orthopedic surgeons rely on clinical tests to help them diagnose knee problems. A common knee injury among athletes is an anterior cruciate ligament (ACL) tear. The most commonly used test for this problem is called the Lachman test. This test is routinely used despite the fact that the Pivot-shift test may be more reliable. In this article, the advantages and disadvantages of each test are presented.

Lachman test for knee instability is positive (indicating a torn ACL) when the lower leg slides farther forward from the femur (thighbone) than it is supposed to. Two test positions are used: one with the knee in neutral alignment and the second with the lower leg rotated slightly outwards (15 degrees). The test is positive if/when the amount it slides (called translation) is greater when the leg is rotated than when the leg (foot) is straight during the testing.

There are various ways to perform the pivot-shift test. The basic test applies a crosswise force of the tibia against the femur while rotating the lower leg. If it shifts enough to clunk (can be felt and sometimes heard as an audible clunk), the test is positive for instability.

Differences in the specific pivot-shift test techniques occur based on individual theories about what is causing the instability and how to test for it. In fact, the authors of this article put together a table of 13 studies using the pivot-shift technique. The type of pivot-shift test done is listed along with a description of the technique. The underlying problem for which the test has been designed was described. These are based on studies by well-known orthopedic surgeons such as Losee, Slocum, Galway, and Noyes to name just a few.

The very nature of how many different ways this test can be performed is the first strike against it. It is a complex test that is easy to interpret differently by different examiners. And it can be positive in people who are naturally overly flexible or who have joint laxity. The amount of force used and/or degree of rotation is left up to each individual doing the test. And if there are other soft tissues damaged, it can cloud up the results.

The authors list a few other disadvantages of the pivot-shift test. First, it isn’t always positive even when there is a deficient ACL. Second, it can be a painful or unpleasant test for the patient. If they involuntarily tense their muscles, it reduces the reliability of the test. Sensitivity (ability of the test to determine a true positive) is much lower for the pivot-shift test compared with the Lachman test.

On the other hand, the Pivot-shift test is highly specific (able to accurately reflect a true negative — showing that the patient does not have the problem). If the pivot-shift is negative or there is a low grade (mild injury), patient outcomes are better with faster return to sports. Patients tend to be more satisfied with treatment outcomes if the pivot-shift test suggests a low-grade injury.

The reason these two tests are being compared to one another is that over time, surgeons have become aware that just using Lachman’s test to diagnose the problem and then repairing the anterior-posterior motion of the knee often left the knee with rotational instability. The pivot shift test is better able to identify the presence of a rotational instability, which must also be corrected during ACL reconstruction.

What hasn’t been cleared up yet is whether it’s more reliable and accurate to keep the lower leg in the neutral position or to internally or externally rotate the lower leg during the pivot shift test. It’s possible that the answers really lies in what type and degree of injury are present.

Some experts have even suggested that the patients’ unique anatomy is what makes the difference in testing and test results. Others believe that the presence of other soft tissue injuries (in addition to the ACL tear) contribute to a variety of patient results to the same test.

Scientists studying this problem have new tools and new technology to explore the normal and pathologic biomechanics of the knee and tests for knee instability. The authors of this article propose that in the future, computer systems with the ability to measure and analyze movement will make it possible to plan ACL reconstruction surgery with each individual patient in mind.

The authors of this article offer their favorite pivot-shift test. The hip is abducted (leg is moved away from the body). This position relaxes the iliotibial band (ITB) along the outside of the leg. With a relaxed ITB, the tibia can rotate. In this way, the results of the test are not influenced by how tight the ITB is (possibly limiting rotation).

A valgus force (from outside of the knee toward the body) is applied to the upper part of the tibia (lower leg). This movement is done while simultaneously moving the leg from flexion (bent) to extension (straight) and internally rotating the lower leg. If the tibia subluxes (jumps or clunks), the test is positive for knee instability. A positive test means that the knee is unstable in forward and backward translation as well as in rotation. This test is a modification of the well-known Losee technique.

The fact that the pivot-shift test provides information on the amount and direction of excess rotational movements (not just forward and back instability) is significant. These findings are important for the athlete who needs to jump, stop suddenly, pivot, shift, and cut quickly. Just repairing or reconstructing the torn ACL will not restore stability in the movements that require rotation. All other soft tissue injuries and imbalances must be identified and corrected.

The examiner must keep in mind that in acute cases (recent injury), swelling may prevent the clunk. Likewise, injury to the medial collateral ligament (MCL) or lack of knee extension for any reason can also prevent subluxation and mask the true results.