News Category: Knee

Total knee replacement (TKR) can be done now using a minimally invasive (MIS) approach. A smaller incision is made and in some cases, cutting into the quadriceps muscle is avoided altogether. This is called a MIS quadriceps-sparing TKR.

In this report Dr. Alfred J. Tria, Jr. offers the benefit of his expertise. He has used this method with 450 patients. He reviews the pros and cons of the quadriceps-sparing TKR. The biggest problem surgeons run into with this operation is the limited visibility. With the smaller incision, the surgeon doesn’t see inside the entire joint.

Getting the implant in place with the proper alignment is the greatest challenge. New technology with electromagnetic navigation may reduce these kinds of problems. The surgeon is able to use the navigation system to see the position of the implant and the surgical instruments.

Early results of MIS quadriceps-sparing TKR are now being published. Two-year data shows patients have less pain, less time in the hospital, and more range of motion when compared to patients with the standard TKR.

Long-term results aren’t available yet. For now it looks like the best candidates for this operation are patients younger than 80 years old who weigh less than 225 pounds and have at least 105 degrees of total knee motion. Patients with minimal deformity who are not overweight and who have more range of motion (125 degrees) have the best results so far.

Total knee replacement (TKR) is a common operation these days. The success of this procedure depends on surgeon skill and planning. Bone shape and size are slightly different for every patient. So bone cutting and aligning the implant are especially important.

In this study surgeons practice a new way to line up the implant using a 3-D computer program. Plastic and cadaver knees are used first before this idea is tried out on live patients.

Before the operation a model or template of the patient’s knee was made using 3-D CT scans. In this way an exact or very close implant match could be made. Using the computer program gave surgeons a chance to move the implant until the desired alignment was obtained.

This program helped the surgeons avoid over rotating the femoral implant, a common problem during TKR. They could carefully plan out ahead where and how to make the best cuts into the bone.

Using the virtual templates cutting blocks were made to match each knee’s unique shape. Results of the computer-assisted TKRs were compared to standard TKRs. The authors report smoother cuts into the bones and smaller gaps between the bones and implants with the templates.

Patient-specific templates are superior to standard instruments used. This new method was easier, faster, more accurate, and less expensive compared to the usual method used. The authors list several problems that still must be solved before this technique can be used on humans. More studies are needed to improve this method.

Patients younger than 50 years old with severe patellofemoral (PF) osteoarthritis (OA) aren’t good candidates for a knee replacement. Loosening from wear and tear in active younger people often leads to implant failure. Cartilage and bone transplantation may be the answer.

In this study 11 patients with severe disability from PF OA were given a layer of cartilage and bone from a donor. The graft is called an osteochondral allograft. The graft forms a shell that is transplanted into the damaged area of the joint.

All patients in the study had an average of four surgeries already. In this operation two patients received a new patella (kneecap). This is a unipolar graft. The rest were given a bipolar graft, which included the patella and the surface of the femoral (thigh bone) side of the joint.

Patients were followed for years afterward. X-rays were used to measure the thickness of the cartilage. Testing of joint motion and function were also done. Eight of the 11 patients were able to delay getting a total knee replacement (TKR) by two to 10 years. The symptoms of arthritis (pain, stiffness, loss of function) were improved for these eight patients during that time.

Allograft of bone and cartilage may be an acceptable alternative to TKR in younger adults with PF OA. This small study offers hope for the use of biologic resurfacing with allografts as a treatment option. If this operation fails, a TKR is still possible.

The results of this study support the use of lateral release and heat treatment of the medial retinaculum for patellar instability. Patients with dislocating kneecaps (patellar instability) were included. This method of treatment avoids extra cuts to open the knee. It also reduces time in the operating room.

The retinaculum on both sides of the kneecap is a band of connective tissue. It helps hold the kneecap in place. As the kneecap goes up and down it must move along a track without sliding to one side or the other.

When present on both sides, the retinaculum keeps the kneecap tracking in the middle. When one side is tighter or looser than the other side the kneecap is more likely to sublux or dislocate causing pain and disability. Usually the lateral (outside edge) retinaculum is tight and pulls the kneecap in that direction.

Treatment was applied using an arthroscope. This tool allows the surgeon to see inside the joint while performing the operation. A thermal (heat) probe was inserted through the arthroscope and used to shrink the retinaculum on the inside edge of the kneecap. The process is called thermal reefing. It tightens up the structures holding the kneecap along the inside edge. The retinaculum along the outside edge of the knee was cut (released).

Patients were followed for at least two years. Pain, function, and patient satisfaction were measures used to assess results. Treatment was successful in 91 percent of the cases. Results were rated as good to excellent for this group. Five of the 62 knees were considered failures with one (or more) dislocations.

The authors conclude that lateral release and thermal reefing is just as good as other methods of treating patellar instability. A rehab program that works within the time frame of healing tissue must be a part of the recovery process. Return to sports must be monitored closely.

Total knee replacements (TKRs) are supposed to provide pain relief and improve function for patients with knee arthritis. In about five percent of the cases, this doesn’t happen. The patient still has pain after TKR. In this report surgeons help other surgeons figure out what’s wrong with each patient and how to treat them.

The first step is to take a history and conduct a careful physical exam. The problem could be coming from somewhere else like the hip or back. Imaging studies and lab tests may help identify infection or fracture. The authors review each of these diagnostic tools and their uses in detail.

Understanding pain patterns can help sort out pain from soft-tissue, implant loosening, or loss of blood supply. Assessing joint stability can give the doctor clues about possible intra-articular (inside the joint) causes of pain, stiffness, or swelling.

The physician must consider other health or mental problems as well. Depression, diabetes, and heart disease are just a few conditions that may be adding to the problem. The patient’s medications may give the doctor an idea of other health conditions present.

The authors say that patients with post-TKR pain should not have revision surgery to find out what’s wrong. The problem should be identified first before treatment is applied. A step-by-step evaluation as described is essential.

The purpose of this study was to compare two methods of anterior cruciate ligament (ACL) reconstruction. Many studies have been done using a patellar tendon versus hamstring tendon graft. This study is different. The surgeons used the same preparation of graft and method of repair for both types of graft.

In other studies the fixation method and procedures are different. The patellar tendon graft has a bone plug at each end. The hamstring tendon graft is made up of several strands of tendon without a piece of bone at the end. The method of fixing the graft to the bone varies.

In this study both grafts had a bony end. Both are put in place using screws. Everyone had the same rehab program after surgery. Patients were followed for at least five years and sometimes longer. Range of motion, strength, and pain were used as measures of results.

The authors report no difference in quadriceps strength between the two graft types. Hamstring strength was noted in the hamstring tendon group. Painful symptoms during kneeling were reported more often in the patellar tendon group. An equal number of patients in each group were able to return to their preinjury level of sports activity.

The goal in this study was to compare two types of ACL repair using the same fixation method. Severe kneeling pain was present with the patellar tendon graft. The hamstring graft in this study with a bone plug gave better knee stability compared to other studies using the hamstring graft without a bone plug.

The authors suggest further studies to compare the good and bad points of each type of ACL repair. There is a need to find a way to reduce problems with pain at the donor site. Hamstring tendon grafts are more complex to prepare than patellar tendon grafts. Ways to improve this problem are also needed.

It’s been over 100 years since doctors first named osteochondritis dissecans (OCD). Despite the lapse of this much time, scientists still don’t know what causes this problem. In this article OCD of the knee is reviewed. The authors discuss the clinical presentation and diagnosis. They also look at patterns of OCD and its prognosis. Current management of the problem is presented.

With OCD a loose piece of bone and cartilage separates from the end of the bone. This is called a loose osteocartilaginous fragment. It looks OCD could be caused by a decreased blood supply to the area. In some, but not all cases, there’s been a traumatic injury to the knee.

X-rays are used to stage the disease from one to four. The more severe stages affect the joint cartilage and first layer of bone in both the tibia (lower leg bone) and the femur (thigh bone). A free or loose fragment is present in stages three and four.

The symptoms of OCD vary but usually there’s pain along the front of the knee. Swelling comes and goes. The more active the person is, the more likely swelling will occur. The loose fragment may stay in place (stage three) or fall into the joint space (stage four). The patient tells the doctor it feels like the joint is catching, locking, or giving way.

Small lesions can be treated successfully without surgery. Reduced activity over a long period of time is usually necessary. Casting and crutches may be needed to limit weight-bearing. Pain medications and an exercise program for strengthening are also used.

Surgery may be needed to remove the loose fragment and repair the joint. The surgeon may drill holes into the bone to increase blood supply and bone healing. Bone grafting may be needed when a crater or hole is left from the missing piece of osteocartilage.

The authors conclude by saying that OCD is not a benign condition. It can cause many problems with joint degeneration. More studies are needed to help define the best treatment for each stage of OCD.

Sometimes young adults with knee arthritis need surgery but can’t have the standard types of operations. They are either too young, too active, or too heavy (obese). The McKeever hemiarthroplasty may be a good option. In this study, surgeons report on the long-term results of a series of 23 knees with this implant. All patients were less than 60 years old. Everyone was followed for at least 12 years.

The McKeever device is a thin piece of metal placed on the tibial (lower leg) side of the knee. It replaces the bony plateau or shelf of bone that makes up the lower half of the knee joint. It has a T-shaped keel underneath to help hold it in place. It’s used most often when arthritic changes only affect one side of the joint (unicompartmental).

Results were best in the youngest patients. The patients who kept the implant the longest were on average nine years younger than patients who needed a second operation. The younger patients kept the McKeever implant twice as long as the older patients who needed a revision.

Everyone agreed they would have the same operation again. It works well to delay the need for a partial or total knee joint replacement. With the McKeever implant they had more function with less pain.

Most patients have a good result after total hip or total knee replacement. Problems occur in about 15 to 20 percent of the rest. Physical therapists from the Sinai Hospital in Baltimore, Maryland studied what happens and how to help these patients.

Patients were divided into groups based on muscle weakness, muscle tightness, nerve problems, and differences in leg-length. X-rays were taken to rule out a problem with the implant itself. Hip abductor muscle weakness was the biggest problem in hips. Knee flexion contracture (unable to straighten the knee fully) was the biggest problem for knees.

In a smaller number of cases poor alignment in other joints caused problems once the hip or knee was replaced. Nerve entrapment causing burning pain and weakness was present in a few patients. A difference in leg length from side to side occurred for various reasons in another small group of patients. The authors reported the changes in function patients had with each of these problems.

Treatment for each soft tissue problem was reviewed. Muscle contractures were treated with aggressive physical therapy, injection, or surgery. In some cases, a custom made brace was used three times a day for 30 minutes (or more). Muscle weakness was treated with aquatic therapy, strength training, and electrical stimulation. Balance retraining was also included.

After three to six months of physical therapy, 92 percent of the patients had restored function. The rest of the patients needed surgery. The authors point out that in a small number of patients with failed joint implants, an aggressive and structured physical therapy program may be needed.

Getting a good result after a total knee replacement (TKR) depends quite a bit on the surgeon’s skill. The right size and type of implant must be selected. Putting the implant in so it’s not too tight or too loose is important. In this study cadavers are used to find out how much joint laxity or looseness is normal. The surgeon can use these values to restore the natural anatomy as much as possible.

A new fluoroscopy-based computerized navigational system was used in this study to measure joint laxity. Fluoroscopy is a type of X-ray that allows the surgeon to see inside the joint during testing. The amount of joint movement was measured in three planes of motion. Two different positions of the knee were used to test ligament laxity. Joint laxity or gap was measured with the knee in full extension and again in 30 degrees of flexion.

The measures were repeated after a TKR was done. The authors report the measurements for anterior-posterior, medial-lateral, and rotational laxity before and after the TKR. They found the laxity values weren’t much different from before to after. There was slightly less laxity along the lateral side of the joint after TKR. They suggest surgeons can use this information when doing TKRs on patients.

This is the first study to use a computerized navigational system to compare joint laxity before and after TKR. More studies like this are needed to give surgeons accurate values for knee laxity. Implanting a joint replacement with as close to normal biomechanics is the goal.

It’s clear now how important the meniscus is for the knee. So important that doctors no longer just remove it. Now they repair it with as little trauma as possible. To do this an all-inside arthroscopic method is used. New repair systems are available for this operation. This study reviews the results of using the FasT-Fix meniscal repair system.

Surgeons describe the parts of the FasT-Fix and the technique used for the repair with this system. Two suture anchors hold the meniscus in place. The repair takes about 11 minutes. Patients were followed for up to 18 months or longer. Measures of success included absence of pain along the joint line, no locking, and no swelling.

The authors report about a 10 percent failure rate. This means that 90 percent of the patients had no symptoms even a year and a half after the surgery. There were no locking episodes, and the knees were stable. There were no limits on sports activity. Everyone went back to work full-time.

There was no obvious reason why some patients failed in this study while most had a good clinical result. The results show that the FasT-Fix system is as good as other systems in use. It’s unique in its ability to avoid damage or injury to the nerves and blood vessels near the meniscus. The authors plan to follow-up to see what the long-term results are.

When the anterior cruciate ligament is torn or ruptured a piece of tendon from around the knee is used as a replacement graft. Most often the hamstring tendon or patellar tendon is used. In this study a central piece of the quadriceps tendon is used instead. Strength of the muscle after the graft is measured and compared to the patellar tendon graft.

Testing was done on 10 cadavers (human knees preserved after death for study). Strength of the 10 knees was measured before removing tendon pieces for the study. A 10-mm wide tendon graft was taken from the middle of the patellar tendon. The same was done on the quadriceps tendon. Tests of strength were repeated for all 10 knees.

The authors report the following findings:

There are many different kinds of implants available for knee joint replacement. Some allow greater motion than others. Some rotate. Others swivel. When the joint is unstable, an implant with “constraint” may be used. Constraint limits motion and improves stability. In this article orthopedic surgeons at the University of Washington in Seattle review four constraint designs available.

These include (from least to most constraint):

Osteolysis or bone loss after total knee replacement (TKR) can be a problem. Tiny flecks of bone and debris from the backside of the implant lead to osteolysis. Over time the implant can come loose or the bone can fracture. This study reports two changes that were made to reduce the risk of osteolysis.

The first step was to polish the baseplate surface of the tibial (lower leg bone) implant. Before that a grit-blasted surface finish was used. The second step was to change the way the implant was sterilized. Before 1993 implants were sterilized with gamma radiation in air. Later this was changed to radiation in nitrogen or gas plasma.

Results were measured by taking X-rays of the implants. The amount of osteolysis was measured. Knee alignment was also viewed. They found the amount of osteolysis was lowered from 34 percent to 6 percent when these two changes were made. Osteolysis was also more severe in the grit-blasted group.

The authors report several other risk factors as well. For example men were 3.6 times more likely to have osteolysis when compared to women. Risk of osteolysis went up when inserts had a longer shelf-life. Knees with a hyperextended angle were more likely to have osteolysis even with the two new changes.

The authors suggest polishing the baseplate reduces loss of polyethylene from the back of the insert. Using a different sterilization process seems to make the surface more fatigue-resistant. A shorter shelf life improves the quality of the polyethylene. Taken together these factors reduced osteolysis. Researchers aren’t sure if all three steps are needed. Future studies will look at each one separately.

Knee joint replacements heat up under certain conditions. In this study Dr. J. W. Pritchett from the University of Washington (Seattle) explores how much the joint warms up compared to healthy joints. He also looks at what causes the increased joint temperature. Too much heat can cause cell death, knee pain, and implant loosening.

People with healthy knees and patients with arthritic knees and joint implants had the temperature inside their knees measured. Some patient had both knees replaced with different types of implants. Eight different prostheses were used in all. Sensors placed just under the skin measured the temperature of the synovial fluid after walking and cycling.

Dr. Pritchett reports only a one-degree increase in temperature in the normal knee after walking. Arthritic knees and some implants had a two- to three-degree increase. The rotating hinge knee replacement had the greatest increase in temperature (seven to nine degrees). This study also showed that ceramic and metal materials carry the heat away from the bone better than polyethylene (plastic). Titanium implants hold the heat more than prostheses made of cobalt-chromium.

It’s not clear how much heat or how long it takes before the heat causes a problem. Doctors are concerned because increased heat can cause scarring and bone loss. The result can be knee pain and joint loosening. Long-term studies of increases in joint temperature with different implants are needed to learn more about this problem.

It’s clear now that female athletes are at greater risk for anterior cruciate ligament (ACL) tears compared to men. The risk is the most in sports that involve pivoting and jumping. Such movements put a high load on the knee joint. In this article screening for risk factors and training to decrease ACL injuries are discussed. The authors review many of the latest research studies on the causes of ACL injury in adolescent female athletes.

There are many theories about the whys and whats of ACL injuries in females. Factors such as thigh length and shifts in hormone levels have been suggested as part of the problem More recently deficits in neuromuscular control have been linked to ACL injuries. But scientists don’t really know how these affect ligament strength or lead to injury.

Studies show that before puberty, boys and girls have the same pattern of muscular control in the knee and leg. After puberty there are fewer fractures but more ligament sprains. Males continue to increase in power, strength, and coordination as they get older. Girls show very little change during puberty. This lack of a “neuromuscular spurt” may increase the risk of ACL injury.

The authors present ways to test for ligament and muscular imbalances. Ideas for neuromuscular training to correct these problems are also presented. They suggest physicians test female athletes for any deficits. Specific training to reduce the risk of ACL injury is advised.

Soldiers in basic training who have not been running are at increased risk for bone stress fractures. In this study military recruits in the Finnish army were studied. The goal was to find out how often and what type of stress fractures occur.

Over 1,000 recruits with knee pain during exercise were included. Some had pain in one knee. Others had pain in both knees. Using MRIs the doctors found 141 bone stress injuries in 110 knees of male and female recruits. Seven percent had one bone stress injury. Another 8.6 percent had other injuries such as meniscal tears or ligament injuries. The rest (84 percent) had normal knees.

Most injuries occurred in the medial (inner side) of the knee. Symptoms of pain with exercise or activity started about three months after military training began. The lower leg bone (tibia) or the thigh bone (femur) was affected most often. This is where most of the weightbearing stress occurs.

An increase in how often or how long trainees exercise is the key to stress injuries. Military recruits or healthy adults starting a new or intensive physical activity are at increased risk for bone stress fractures. The authors suggest a routine MRI for anyone with knee pain caused by exercise.

Knee pain along the front (anterior) part of the knee is common and can be caused by many different problems. In this article Dr. Wm. Post, a private practice orthopedic surgeon reviews the diagnosis and treatment of anterior knee pain.

Dr. Post gives a table full of information to compare one knee problem from another. Type of pain, signs and symptoms, and test results are presented for each knee condition. The usual treatment for each one is also listed. Dr. Post makes it clear that an accurate diagnosis is the key to successful treatment.

Anatomy and the specific causes of pain based on anatomy are reviewed in this article. Not all knee pain is caused by visible or measurable changes. On the other hand, changes can be measured on X-ray without pain or discomfort of any kind.

Surgery isn’t always the best answer for knee pain, even when X-rays show an alignment problem. The author reviews results of nonsurgical treatment reported by other studies. He does the same with surgical management of anterior knee pain.

Much has been discovered in the past 10 years about knee pain. More knowledge is needed to treat it effectively. Most evidence points to nonsurgical treatment as the preferred choice for the best outcomes.

In this case report of an injured athlete, doctors point out the need for immediate surgery when compartment syndrome is present. A 17-year-old soccer player was hit in the left thigh when he crashed into another player.

Bleeding and swelling into the area put so much pressure on the skin and soft tissues underneath that surgery was needed to release the pressure. This condition is called anterior compartment syndrome. Three incisions were made and fluid removed from the thigh. This type of surgery is called a fasciotomy. The pain and swelling went down quickly. Sensation improved and lab tests to measure bleeding went back to normal.

Three days later the patient had a second operation to sew the wound back up. The patient healed normally and returned to full sports participation within six months’ time. Without proper treatment damage to the muscle can’t be reversed. Infection and death are even possible.

The authors say this case points out the need for quick diagnosis and fast response when compartment syndrome is present. Full recovery may not be possible with delayed treatment.

Gone are the days of long stays in the hospital for knee surgery. More and more studies are reporting good results with minimally invasive surgery (MIS) for total knee replacement (TKR). In this report one surgeon replaces the knee joint in 50 patients on an outpatient basis.

The patients are carefully chosen. They must be in good health. They can’t be overweight or obese. Only a small incision was used. All but two patients went home the same day. There were no problems linked to early discharge.

What do doctors credit this advance in treatment to? They say new critical pathways are the answer. What does that mean?