News Category: Knee

Total knee replacement (TKR) is the most common joint replacement surgery now. More TKRs are done than even total hip replacements. As the number of TKRs goes up, so does the number of revision surgeries. The rising medical costs for two or more operations are a concern. The authors of this article compare costs of primary and revision TKRs from different health care systems around the world.

The results of this study show that the cost of TKR and revision TKR is much less than heart surgery or organ transplantation. Not only that, but the costs associated with TKR have gone down over the years. Better patient management has led to shorter hospital stays and faster recovery. Patient quality of life has improved greatly with TKR.

Revision TKRs cost more and are more difficult to do. There are more complications with revision surgery but pain relief and improved function make it worth it to the patients. Comparing costs of TKRs and revision TKRs isn’t easy because data collected varies from country to country.

Any treatment that costs less than $20,000 is considered cost effective. All countries surveyed reported the cost of primary and revision TKRs as less than this. New Zealand was the lowest at $7101 for a primary TKR compared to the United States at $15,476. Revision TKR costs between $10,000 and $15,000 in most countries.

The authors say as the adult population ages, more and more TKR surgeries are going to be done. There may be some ways to reduce the number and cost of revision surgery. First, a registry to collect patient data may help point out patterns in patient selection or treatment that could make a difference. Improved implants should also help. And many studies have shown that high volume surgery centers have the best results.

When it comes to deciding who should or shouldn’t have a total knee replacement (TKR), surgeons agree on two things:

Some patients who get a total knee replacement (TKR) develop a very stiff knee afterwards. Scar tissue and soft tissue contracture (tightening of the muscles) are often the main cause of the problem. In this study, surgery and intense rehab are used to treat patients with too much scarring, a condition called arthrofibrosis. The results are presented for 18 knees in 17 patients with arthrofibrosis after TKR.

Treatment included removing the scar tissue, a procedure called an arthrotomy. Sometimes the plastic spacer inside the joint was taken out. In others patients, the spacer was left in. Intensive physical therapy followed for six to 12 weeks. A special brace called the Customized Knee Device (CKD) was used to help improve joint motion.

Results were measured by pain, motion, function, and patient satisfaction. Good to excellent results were reported by two-thirds of the patients. Only one patient was unhappy with the final outcome. Despite the intense therapy program, five patients (six knees) had to be manipulated to regain motion. Manipulation was done by the surgeon with the patient under anesthesia.

The authors conclude that patients with arthrofibrosis after TKR often have complex and difficult-to-treat problems with loss of motion. The rehab program after arthrotomy seemed to have good results for many of the patients. Other studies using intense rehab have shown improved results, too. The best combination of rehab activities remains unknown at this time and the subject of future studies.

A popular method used to repair anterior cruciate ligament (ACL) tears is the hamstrings tendon graft. Specifically, a piece of the semitendinosus-gracilis (STG) portion of the hamstrings is used to replace the ACL. The hamstrings help flex (bend) the knee. In this study, knee flexion strength is measured two years after the ACL repair.

Earlier studies have shown that knee flexor strength is reduced for the first month after surgery. More recently other studies have shown longer-term weakness related to STG tendon harvest. In this study twenty (20) patients of one knee surgeon were included. Joint motion, function, sensation, and joint laxity (looseness) were measured after surgery.

Patients were tested in the prone (face down) position to allow as much knee flexion as possible. Joint range of motion and muscle strength were measured. The results showed loss of motion and decreased flexor strength two years after ACL reconstruction with an STG graft. The patients’ perception of normal sensation seemed to be linked with function.

Although the STG graft avoids the problems of quadriceps tendon grafts, they do have their own down side. This study confirms the findings of other reports that flexor strength is impaired after ACL repair with an ATG autograft. More study is needed to find the best rehab strategy to regain full strength and use of the hamstrings.

Researchers from the Australian Institute of Musculoskeletal Research offer one of the first reports of long-term results from arthroscopic anterior cruciate ligament (ACL) repair. Patients were followed at least 10 years.

All patients had ACL reconstruction using a patellar tendon autograft. Autograft means the tissue was taken from the patient’s own knee. The patellar tendon is located at the front of the knee just below the patella (kneecap). A single incision method was used to perform the reconstruction. If the meniscus was torn, it was also repaired at the same time.

The authors report excellent long-term results 13 years later. Most patients could do moderately strenuous activities without pain, swelling, or giving way of the knee. More patients had swelling after the first seven years than any other symptom. Joint laxity (looseness) was more common in athletes who had the meniscus removed.

They found that graft rupture was more likely to occur in athletes younger than 21 years. The risk of rupture was greater in those who had the meniscus removed. The authors suggest graft rupture after ACL repair with meniscectomy shows the effect of years of increased strain on the graft. Males and females were affected by graft rupture in equal numbers.

Three-fourths of the patients had signs of arthritis seen on X-rays. Almost half also had loss of full knee extension, another sign of arthritis. These changes were first noticed between five and seven years after the ACL surgery.

The authors conclude the long-term results of endoscopic ACL reconstruction are good. There were signs of degenerative changes but function remained good. Increased joint laxity was more common in patients who had a meniscectomy. They suggest early ACL repair after injury to avoid the risk of a meniscal injury later with joint degeneration in the long run.

Patellofemoral pain syndrome (PFPS) is a common cause of knee pain in sports athletes. For a long time it was believed that the kneecap (patella) was off kilter in PFPS. As it moved up and down in its track over the knee joint, the patella slipped off to the side.

But scientists have been able to show that the hip may be part of the problem. In this study, physical therapists test hip strength and flexibility in 35 patients with PFPS. A six-week program of hip exercises was prescribed.

Strength, flexibility, and clinical tests were performed before and after treatment. Level of pain was also measured before and after. Results were compared with the following findings:

The best way to regain full function and prevent arthritis years later after an ACL repair is by getting full motion back first before strengthening. These are the results of ACL rehab reported by J. Richard Steadman, MD, the founder of the Steadman-Hawkins Research Foundation in Vail, Colorado.

Dr. Steadman advises the order of rehab should be: motion first, then mobility, strength, power, and eccentric loading. Eccentric loading occurs when a muscle is fully contracted and slowly lengthens.

Focusing on mobility first prevents scarring and adhesions between the patella tendon and the tibia (lower leg bone). Loss of patellar motion seems to lead to postoperative stiffness and later, arthritis.

Rehab should vary based on the type of ACL repair that’s done. For example, rehab after ACL repair with a single-hamstring graft shouldn’t be too active at first. Double-bundle grafts may be a better choice in order to avoid degenerative joint disease 10 years down the road.

Dr. Steadman wants his patients to get 80 percent of their knee motion back during the first week after ACL repair. Strength training is delayed until motion and mobility have been restored. So for example, biking and walking are okay but heavy resistance or weight training are not allowed.

This new approach to ACL rehab may help avoid scarring and stiffness. Maintaining mobility between the patellar tendon and the tibia reduces the compression on the joint itself and prevents degeneration.

Kevin R. Stone, MD from The Stone Research Foundation in San Francisco, California conducted this study. The goal was to see if a meniscus allograft would survive in a severely arthritic knee. An allograft is tissue taken from a cadaver (donor after death) and transplanted into a live patient.

Earlier studies showed graft failures were common when the patient had advanced joint disease. Until now patients over age 50 or with severe arthritis weren’t considered for a meniscal allograft.

But it’s a catch-22 because leaving a torn meniscus alone means pain and loss of function for the patient. Taking the meniscus out results in arthritis. Meniscal allograft may offer at least one other treatment option.

All 45 patients in this study had been treated before by removing the torn meniscus. The operation is called a meniscectomy. Pain and loss of function persisted after the meniscectomy. Conservative care with drugs, therapy, rest, and exercise failed.

Patients then received a meniscus allograft. After surgery to implant the allograft, each patient followed the same rehab program. During the first four weeks, the graft site was protected as much as possible. Rehab was advanced slowly during the next four to 12 weeks. Strength training and a return to activity was the final phase.

Almost 90 percent of the meniscus allografts survived at least two years. Some lasted up to seven years. Pain, activity, and function were used as the three primary measures of success/failure. Patients who had failed implants either had the graft removed or they received a joint replacement.

The results of this study show that meniscus allograft can be used in older adults with severe arthritic changes. The author suggests previous cautions against allografts in these groups may be overstated.

Debridement or the removal of damaged tissue is an operation commonly used for torn meniscus in the knee. Would it work for people with joint damage from osteoarthritis (OA)? Surgeons from Brown Medical School in Rhode Island studied 122 patients with knee OA to find out.

All patients were treated first with antiinflammatory therapy. They didn’t respond well so debridement by arthroscopy was done next. In this operation, the surgeon removed any damaged or loose flaps of cartilage. The edges were smoothed. Any loose pieces were also taken out. The joint was flushed with saline solution to clean it out.

Pain was measured before and after the operation. X-rays were used to assess the joint space width and knee alignment. Success was defined by pain relief. Overall 65 percent of the patients had good pain relief and considered the operation successful. Fifteen percent (15%) of the failures went on to have a total knee replacement.

The authors report most patients had pain relief in the first six months after debridement. Some continued to improve for up to two and a half years after the arthroscopy. They found that patients with good knee alignment before surgery had very little pain after surgery. Anyone with knock-knees (a condition called genu valgus) or narrow joint space had a poor result.

All in all, they found that the severity of the cartilage damage was the best way to predict the final result. The more severe the lesions, the worse the postoperative results. Patients with cartilage damage throughout the entire knee joint had the most pain and were more likely to have a failed arthroscopy.

The authors conclude arthroscopy to debride the joint is a good treatment option for patients with mild OA. Success depends on the severity of cartilage damage, which isn’t always known until the time of the operation. Patients must be advised ahead of time that results of debridement can’t always be predicted ahead of time.

ACL ligament repairs are done today using a tendon transplant from either the hamstrings muscle at the back of the knee or the patellar tendon from the front of the knee. The graft is an autograft because it’s taken from the patient. In this article, researchers show how time and temperature affect the graft stiffness.

ACL tendon grafts must be prepared before placing them in the knee joint. First the tissue is harvested or removed from the body. It is preconditioned while in the operating room. Both the temperature and the amount of stiffness are preset. The idea is to increase the stiffness by lowering the tissue temperature.

However, when the graft is in the body, it returns to body temperature. This increase in temperature increases the length of the graft, a process called stress relaxation. In this study tendon grafts from the hamstring muscle of cadavers (bodies preserved after death for study) were tested. Each tendon graft was looped to make a double-strand graft and tested using a special hydraulic testing machine.

The authors report that the tendon grafts taken from the hamstring muscle lose tension and stiffness after implantation into the knee. They say it may help to keep the grafts at body temperature during the operation instead of cooling and then warming them again.

It appears that there is a wide range of stress relaxation that can occur. It’s not possible for the surgeon to predict how much the graft will relax in stiffness or tension. This study shows that graft tension and stiffness will decrease after ACL repair. More study is needed to find a way to prevent knee laxity (looseness) after ACL repair.

This is the third follow-up report on a group of patients treated between 1986 and 1988 for anterior cruciate ligament (ACL) rupture. The patients were divided into three groups. Each group had a different method of ACL repair.

The first group had a primary repair using sutures to stitch the torn ligament back together. The second group had an ACL repair just like the first group but with an added feature. The graft repair was reinforced with a braided piece of tendon taken from another muscle. In the past, braided polyethylene was also used. This graft is called a ligament augmentation device. It’s inserted to increase the stiffness and strength of the repaired ligament while it’s healing.

The third group had an ACL repair with a bone-patellar-tendon-bone graft. The graft is taken from the patellar tendon along the front of the knee. A small piece of attached bone is also used.

The authors compared the results of these three methods of ACL repair at the end of one, five, and 16 years. Level of function, activity, motion, and strength were measured and compared. X-rays were taken to measure the amount of osteoarthritis present.

The results showed that group one (primary repair) had 10 times more re-ruptures and revision surgeries than the other two groups. Only 10 percent of group three (bone-tendon graft) had any joint instability compared with almost half (44 percent) in group one and one-third (29 percent) in group two.

This study confirms the findings of other studies. Simple suture of a torn ACL is not advised. Although the ligament augmentation method had better results than the simple repair, over time the device failed. The knee became unstable. The authors say the best long-term results are obtained with the bone-patellar-tendon-bone graft. No matter what method is used, about 10 percent of the patients had arthritis in that knee.

In this report doctors review the latest developments with tissue engineering for ligaments. The anterior cruciate ligament (ACL) of the knee is the main target. They also describe a new three-dimensional (3-D) model they are using at the University of California (Los Angeles) to study ligament engineering.

ACL repair has come a long way in the last 30 years. There’s a 90 percent success rate now. Athletes are even able to return to their former level of competitive play. But problems persist. For some patients, knee pain, weakness, and loss of motion leave them unhappy with the results.

So scientists keep working on finding a good synthetic graft ACL substitute. The first step is to study and understand how normal ligaments heal when injured. The authors describe what is currently known about this process. The hope is to find a way to provide a pathway for ligament healing instead of using a synthetic replacement.

Ligament engineering may depend on finding repair cells that can build a scaffold (base structure) for regrowth of the ruptured ACL. A second option would be to use a synthetic substitute as the base and get replacement cells to fill in around it.

The various types of cells, growth factors, and scaffolds that might work are under investigation and reviewed briefly. Studies are still in the experimental phase using rabbits and mice. The final result must be a ligament that can withstand forces and loads typical in the knee under normal circumstances and during athletic play.

There’s been a rash of recent cases of osteonecrosis associated with medial meniscus degeneration. More than 35 cases have been reported recently. This study adds another five more cases.

Osteonecrosis is the death of bone. Degeneration of the medial meniscus (cartilage along the inner side of the knee joint) is an age-related condition. The previous 35 patients had the meniscus removed arthroscopically. Then they developed osteonecrosis.

In the five patients from this study, painful knee symptoms of meniscus degeneration were followed by spontaneous osteonecrosis (SON) of the knee. None had knee surgery for meniscus tears. All of the patients were men over 60 years old. MRIs taken early on showed no sign of SON.

Despite exercises and non-inflammatory drugs, all five had increased pain about two months later. A second MRI showed the presence of SON. The authors aren’t sure what (if any) connection there is between medial meniscus degeneration and SON. They saw over 800 other patients with medial meniscal tear. All were more than 60 years old. Non had SON.

In earlier studies it was suggested that arthroscopic meniscectomy was the cause of SON. With this study, it appears that some other mechanism is at work. Older adults with meniscus degeneration should be evaluated for the possibility of SON before the meniscus is removed. Removing the meniscus is known to speed up the break down of the joint with early arthritis.

Carticel was used in patients who had defects in the joint cartilage of the knee. The defect was of the femoral condyle, the rounded end of the thighbone that forms the top half of the knee joint. All patients had a poor response to surgical repair before receiving Carticel.

The FDA reported a 3.8 percent adverse event (AE) rate. AEs included graft failure, delamination, tissue overgrowth, and infection. Delamination is the separation of the outer coating of the graft or splitting of the graft into separate layers.

The FDA says these problems are fairly common and are not unique to Carticel. Safety of this product will continue to be monitored and reported to the public. Only the company making Carticel must report problems and only those AEs that occur within the first 15 days.

Researchers studying Carticel say problems can occur from day one up to six years later. The overall AE rate may be really more than 3.8 percent if all cases are reported.

Severe cartilage damage in the knee can be repaired with the use of donor tissue. Plugs of cartilage with attached bone can be harvested after a donor’s death. The donor tissue is called an osteochondral allograft or OCA. These grafts have the best results when they are transplanted within 28 days.

Research at the Cartilage Restoration Center (Rush University Medical Center) has made the news. OCA was placed in 25 live patients with knee pain and problems from osteochondral damage. The results show an 84 percent satisfaction level among patients. Activity level and symptoms (including pain level) are best when the graft is implanted less than 28 days after removal from the donor.

Follow-up three years later showed 88 percent of the grafts were accepted and incorporated into the knee. The new cartilage and layer of bone had become a functional part of the knee joint. X-rays confirmed the results.

The results of this study match the results of other studies for grafts implanted within seven days of harvest. The scientists suggest surgeons pay attention to their recommended graft age of less than 28 days. Grafts older than that may give less than satisfactory results for patients.

Twenty-five years ago surgeons tried a procedure called abrasion arthroplasty to stimulate cartilage repair in the knee. The idea was to cause bleeding to encourage healing and cause cartilage to grow again. The practice was stopped because too many patients reported increased pain after the operation.

At least one group of surgeons in Germany didn’t put the practice aside. They realized the problem was drilling or cutting the bone (instead of shaving or abrading) and going too deep. Just the right amount of stress on the cartilage is needed to generate cartilage regrowth. Removing too much bone weakens it and makes weight-bearing more painful.

The results of several long-term studies of 100s of patients who received abrasion arthroplasty are now available. It turns out the operation actually helped many patients avoid a total knee replacement. Repair growth and function got better and better months and even years after resurfacing the bone.

Results were also reported for another study of patients receiving autologous chondrocyte implanted (ACI)-covered flaps to repair cartilage defects. Healthy cartilage cells from each patient were removed and grown in a laboratory then reimplanted in the patient. Twenty-five years of data shows that 85 percent of the grafts lasted 10 or more years.

The same type of data was collected for osteochondral allografts (OCA). In this operation the patient receives cartilage with a bone plug from a donor. Holes are drilled and the OCA is inserted in the damaged joint. The allograft restored bone stock making conversion to a total knee joint easier years later.

As a result of these studies, orthopedic surgeons are taking a second look at cartilage repair techniques tried and abandoned years ago. Tweaking the process may bring about new ways to salvage damaged joints without replacing the joint.

Most athletes who injure their anterior cruciate ligaments (ACLs) want to rehab and get back on the field or court. Many do but some never seem to get back to their top form. Others have a stable knee but one that develops arthritis early in life. So the search is on for a better way to repair this knee ligament.

In this article surgeons from around the world (Japan, Greece, and the United States) discuss the use of double-bundle ACL repair. They compare the results with the current, standard single-bundle repair.

Double-bundle refers to how the tendon graft is split into two parts. One-half replaces the front (anterior) half of the ACL. The second half replaces the back or posterior portion of the ACL. This mimics the natural anatomy of the ACL.

The double-bundle repair is a new technique used only by specialists at this time. It’s a more difficult operation to perform. Studies have not proven its value yet over the standard single-bundle method.

The key benefit to the double-bundle method is the control it gives over tibial rotation. The natural (undamaged) ACL allows the lower leg bone (tibia) some movement when the foot is planted and the player pivots or shifts the knee in another direction. A single-bundle repair doesn’t allow the knee this extra rotation.

Using the double-bundle ACL repair appears to restore normal kinematics (motion) of the knee needed for high-level athletes. The hope is that this improved rotational stability will prevent the early degenerative changes that lead to arthritis in many single-bundle repairs. Studies are needed to compare the long-term results of single- versus double-bundle repairs.

Past studies have shown that surgeons who do more total knee replacements (TKRs) have the best results. This study looks at hospital volume in a similar way. Results showed that death rates and rates of infection are lower in hospitals with a high volume of TKRs. Other factors linked with poor outcomes are also reported.

Data for over 200,000 TKRs done in California over a 10-year period of time was used in this study. Researchers were looking for significant predictors of complications. Factors reviewed included patient age, gender (male or female), and type of insurance. Volume of patients treated in each hospital was also considered.

The results showed that age and health problems were linked with death rate. Both of these factors were more likely to result in higher infection rates leading to death. Age was also a risk factor for fatal blood clots to the lungs. Blacks and Hispanics were more likely to have blood clots and infections.

Medicare patients and patients at low-volume hospitals had the highest rate of complications after TKR. The authors say this information will help low-volume hospitals improve the quality of care and results after TKR. Future studies focusing on success factors in high volume hospitals should be the next step. Low volume hospitals may be able to use some of the methods used by high volume facilities.

When a total knee replacement (TKR) fails the next step may be a fusion or arthrodesis. In the late 1970s fusion rates were fairly low post-TKR (64%). It wasn’t a very successful operation. Since that time new fusion methods have been developed. In this report, surgeons review the advantages and disadvantages of fusion methods used today in patients with a failed TKR that can’t be revised.

According to today’s research results, there still isn’t a “best method” for knee arthrodesis. Each one has its good points and bad points. The two main ways to perform the arthrodesis are internal and external fixation. With internal fixation a long pin or “nail” is used down through the center of the thigh, knee, and lower leg bone.

The results are better with this method than with external fixation. Studies show a 95 percent fusion rate for internal fixation compared to 64 percent for external. Internal fixation is useful when the patient has lost a lot of bone from the insertion and removal of the TKR. This type of nail can’t be used when the patient has a hip replacement on the same side or when there is active infection around the site of the TKR.

External fixation uses a variety of different pins, rods, rings, and frames outside the leg. One problem with this treatment method is that fractures and infection can occur at the pin sites. The pins can come loose before fusion takes place. The device is very bulky. Early weight-bearing for walking is an advantage. Bone grafting isn’t needed. The fusion is solid in about six months.

The authors conclude for some patients with a failed TKR, knee fusion or arthrodesis can reduce pain and avoid a long rehab program. Fusion is considered a “salvage” procedure. It saves the leg from amputation but does not preserve full function. The surgeon must be familiar with the details of both types of surgery. Choosing the right one for each patient is very important.

Meniscus transplants may be needed in young patients with severe damage of the knee after removing the meniscus. Without this important piece of cartilage, serious problems can develop later. The use of allograft (donated) meniscus is discussed in this article.

The authors review the normal anatomy and function of the meniscus. They also present the main ways used to preserve allograft tissue. These include fresh, cold-preserved, and freeze-dried. Fresh grafts can only be stored for about one week. Freeze-dried grafts don’t reconstitute well so these aren’t used anymore. That leaves fresh-frozen allografts, which aren’t always available.

Meniscus transplantation is only used in patients less than 40 years old who have not been helped by other nonsurgical treatment. X-rays must show a narrowing of the joint space. Bracing to unload the joint and exercises to strengthen the muscles around the joint should be tried first.

The allograft is matched for size using X-rays and CT scans of the patient’s normal knee. Arthroscopic surgery is used to evaluate the knee for the transplantation. Then open incisions are made to insert and suture the new meniscus.

The authors describe details of the surgical technique used for the transplantation. Careful placement is needed to provide proper contact points and weight distribution. The anterior
cruciate ligament is repaired at the same time if needed.

Allograft meniscal transplantation is a good option for some young patients. It restores knee function and stability and reduces pain. More studies are needed to find out what the long-term results are of this treatment method before using it routinely.