FAQ Category: Knee

It sounds like you have a defect or hole in the articular cartilage. This is the cartilage that lines the joint and sits right up against the bone.

We don’t know for sure that if left alone, the articular cartilage would eventually heal on its own. The process of what happens over time without intervention or treatment is called the natural history of a condition.

Right now, it’s assumed that damage to the articular cartilage leads to arthritis sooner than later. But there’s no real evidence to support this view. Most of the studies done so far haven’t been on single (isolated) defects of the articular cartilage. Injuries treated have included additional damage to the joint such as an ACL tear (ACL = anterior cruciate ligament).

The articular cartilage doesn’t have much of a blood supply of its own. It relies on movement of nutrients in fluids that cross the cartilage bringing supplies like a wagon train. But the fluid can’t cross holes in the cartilage and that’s a problem. Without a healthy, intact matrix of bone and cartilage, it’s like the wagon coming to a canyon with no bridge to get across.

Since that time, three different surgical techniques have been developed and tried for this type of injury: 1) microfracture, 2) autologous chondrocyte implantation (ACI), and 3) osteochondral autograft transplantation (OAT). Here’s a brief explanation of each one.

Microfracture involves drilling tiny holes through the cartilage, past the first layer of bone underneath, and into the bone marrow. There’s a rich blood supply there and drops of blood well up through the holes to aid the healing process.

Autologous chondrocyte implantation requires removing some of the healthy cartilage cells, taking them to the lab, growing more healthy cells, and then putting them into the holes or defects in the knee.

And osteochondral autograft transplantation refers to harvesting healthy cartilage cells from a part of the knee that doesn’t bear weight (and isn’t damaged) and using those plugs to repair the damaged area.

Each of these techniques has its own advantages and disadvantages. According to studies done so far, there’s no clear winner. But in a recent report by surgeons revisiting the question of which one has the best results it was suggested that microfracture seems to be the best choice for treating articular cartilage defects.

It is a one-step procedure and less expensive than the other treatment methods. Pain levels, function, ability to return-to-sport, cost, and overall failure rates over time were used to compare results.

But your surgeon is the best one to advise you. Some of the treatment choices depend on how much and what type of damage is present. It’s a whole different picture if there is any knee instability from ligamentous damage. And your age can make a big difference, too. Younger patients seem to respond better to the osteochondral autologous transplantation (OAT) procedure compared with older adults (30 years old or older).

There are several layers of cartilage in the knee. The C-shaped meniscus between the bones is the most commonly known. But your son has damage to the next layer down: the articular cartilage. This is a more pliable, softer cartilage that lines the inside of the joint. It’s between the meniscus and the bone.

Repairing damage to the articular cartilage is a little more complicated than stitching the meniscus back in place. With defects or holes in the cartilage, it’s more a matter of plugging them up and smoothing them over, then letting nature take its course.

The type of surgery you mentioned is called osteochondral autograft transplantation (OAT). The surgeon does, indeed, harvest plugs of good, healthy chondrocytes (cartilage cells). These are taken from a part of the knee joint that doesn’t get used much (non weight-bearing site). The plug (or several plugs) are then used to repair the lesion.

The technique works fairly well (especially in young athletes) but there is some question about durability. Long-term studies just aren’t available yet. The outcomes after two years seem positive. But there are some failures and the reasons for these failures have not been determined.

Studies are ongoing to investigate the results of cartilage repair. Clearly more studies are needed to find out what happens in the long-run and how durable this type of repair really is.

It’s clear now that a torn meniscus (cartilage) in the knee should be repaired whenever possible. The previous practice of surgically removing the meniscus resulted in early osteoarthritis. So that practice has been abandoned unless it’s completely unavoidable for some reason.

But there isn’t a lot of data on these kinds of injuries in younger patients (children and teens). A recent study published by surgeons at the Mayo Clinic in Rochester, Minnesota looked at just teens (up to and including age 18) who had meniscus tears along with damage to the anterior cruciate ligament. They compared the results of surgical treatment for this group with another (previous) group studied who just had meniscal tears.

The measure used to determine results included knee range of motion, stability of the joint, pre- and post-op X-rays, and function. Function was assessed by looking at the activity level before injury, just before surgery, and after surgery. Everyone was in a rehab program after surgery and treated with the same protocol.

They found that return-to-sports involving sudden changes in direction (pivoting and cutting) was possible six to nine months after surgery for those with complex injuries before surgery. Complex means more than one part of the knee was damaged.

Only those athletes who demonstrated good knee stability after surgery were released to full participation. Patients with just a meniscal tear were able to return to their pre-injury level of sports participation much sooner (four to six months after surgery) — if the meniscal repair was successful. And success was defined as no pain (or only mild pain that didn’t restrict activities) and no locking, catching, or swelling of the knee.

There is a high rate of meniscal retear even with rehab so a bit of caution is advised (and obviously practiced by your coach). Retears can’t always be repaired (or re-repaired in this case). Removing part or all of the meniscus often leads to early arthritic changes in that knee and that’s what surgeons, coaches, and patients would like to help patients (players) avoid.

It sounds like you might have had a procedure called autologous chondrocyte implantation (ACI). In this technique, a number of healthy chondrocytes (cartilage cells) are harvested (removed) from a nonweight-bearing area of the joint.

These chondrocytes are then taken to the lab where they can be stimulated to grow even more healthy cells. When there are enough intact and healthy chondrocytes to patch up the hole, surgery is done to implant them in and around the lesion. This is the favored method of repair for large, full thickness, painful cartilage lesions.

For you, the first step is to go back to your orthopedic surgeon for an examination. It’s easy to assume that any new symptom or recurrence of knee pain is from the previous injury and repair. But that might not be the case at all, so an evaluation is needed.

If your surgeon determines that a look at the repaired cartilage is in order, there are several ways to do it. But evaluating the quality of tissue after cartilage repair isn’t easy.

The surgeon can go back in with an arthroscope and take a look but this requires another surgery and is invasive. During the arthroscopic procedure, the surgeon takes a small piece of the healing tissue to examine it under a microscope. No one knows if this procedure (which disturbs the healing or healed tissue) might cause problems later.

MRIs have been used because it is a noninvasive way to look inside the joint. But standard MRIs don’t show the cellular structure of the cartilage in enough detail to really assess the repair tissue.

There is a newer MRI technique under investigation right now. It’s called dGEMRIC– dGEMRIC stands for delayed gadolinium-enhanced MRI of cartilage. The radiologist puts a dye into the knee joint — that’s the gadolinium compound (short for gadolinium diethylene triamine pentaacetic acid or Gd-DPTA).

The gadolinium spreads throughout the joint and into the cartilage. The gadolinium seeps in the best wherever there is healthy cartilage tissue with plenty of glycosaminoglycans (GAG). GAGs form an important component of connective tissues. They attract water, which helps keep the cartilage healthy and slippery for joint motion.

High levels of gadolinium indicate healthy articular cartilage. Low levels are a sign of damage to the joint surface, usually from osteoarthritis. Before undergoing expensive imaging tests, see your orthopedic surgeon and find out what he or she recommends. A simple X-ray may be all that’s needed for the problem at hand.

Defects or lesions of the articular cartilage that lines the surface of your knee joint are called full-thickness when the cartilage pulls away with a piece of the underlying bone still attached. Damage like that often causes painful swelling, locking of the knee joint, and instability.

Surgery to repair the problem can be done in a variety of different ways. One is called microfracture. The surgeon goes down to the bone level and drills tiny holes into the bone marrow. Blood from the bone marrow rises up through the holes and initiates a healing response. This technique works well for small defects.

But large, full-thickness lesions have better results when the cartilage implantation is done. Just as the surgeon told you, healthy chondrocytes (cartilage cells) are harvested from a non weight-bearing area of the knee joint and taken to a lab where they are treated to grow more cells. When there are enough intact and healthy chondrocytes to patch up the hole, surgery is done to implant them in and around the lesion.

Results are very good and long-term studies confirm that healing is successful. In fact, testing done anywhere from nine to 18 years after the original autologous chondrocyte implantation (ACI) has been done. Good quality of repair tissue (very similar to the surrounding normal cartilage) has been demonstrated.

Sometimes osteophytes (bone spurs), bone cysts, and bone edema (fluid) develop in, under, or around the repair tissue. These new lesions don’t seem to bother the patients or affect knee function.

So although the analogy of a pothole is a good one in terms of explaining deep damage to the knee joint cartilage and using the chondrocyte implantation repair to fill in the defect, that’s where the similarities end. Your “pothole” will be more than just patched — it will be repaired with good healing at the cellular level.

Cartilage is tough, but flexible body tissue that connects the joints. It needs to be tough to do its job. But, because of make-up of the tissue (very little blood supply), once it has torn, it is difficult for cartilage to heal properly.

Has your mother seen a surgeon about possibly having surgery to repair the cartilage? There are some options that are available for this type of repair, but a lot depends on what the injury actually is, how severe it is, and even the level of activity of the patient.

If you feel you have injured the cartilage in your knee, it is important to have this checked by a doctor. Self-diagnosis could lead to other knee problems because you could be wrong. In any case, these are the most common and probable signs and symptoms of an injured cartilage of the knee:

– Pain in your knee
– Swelling of the knee
– Tenderness when pressing on certain spots
– Limited knee motion
– Popping or clicking sound from within the knee when it is moved

Runner’s knee, or chondromalacia patellae, can be caused by several things. In young people, it’s most often caused by overuse, such as running. It can also be caused by injury, misalignment of the kneecap or arthritis.

The standard treatment for this problem is rest and limited activity. Nonsteroidal anti-inflammatories (NSAIDs) may help, as well. Your son’s doctor may have prescribed physiotherapy, which would likely be helpful because a physical therapist can check to see how your son walks and runs. A step that is off just a bit could throw the balance, affecting the knee. Finally, it has also been found that worn out running shoes, or incorrect running shoes, can contribute to this type of knee problem.

This question is impossible to answer without knowing what type of problem you may be having with your knee, what type of pain you are experiencing, and what brings on the pain. In general, however, the rule of thumb is “if it hurts, stop.” Continuing your activity and ignoring the pain may make things worse and more difficult to treat.

Patients are always advised that complications can occur with surgery. Some of those problems are standard and can develop no matter what kind of surgery is done — for example, poor wound healing, infection, formation of blood clots, even death.

Blood loss is another common event in many operations. Total knee replacement can involve quite a bit of blood loss. Sometimes it’s even necessary to transfuse the patient with additional units of blood. Researchers are trying to figure out just what is causing so much bleeding during this procedure. They know that cutting into the bone is a major source of blood loss. But there might be other factors such as age, sex (male versus female), or the overall health of the patient.

One group of orthopedic surgeons from France investigated whether or not blood loss was linked to the type of fixation used to hold the implant in place. In a recent study, surgeons from France took a look at fixation methods as a potential risk factor for bleeding. Fixation refers to the way in which the implant is placed and held in the bone. Some implants can be put in place without cement to hold them there. This method is called a press-fit fixation. The bone is cut and the implant pressed into the bone in such a way that it holds without cement.

The other most common fixation method is with cement. There’s been some suggestion that blood loss is more likely with cementless implants. That’s because once the bone is cut, there is quite a bit of bleeding and nothing to stop it.

The exact mechanism by which cemented implants might reduce bleeding isn’t completely clear. Some experts suggest that when cement is used to hold the implant against the bone, the cement itself may plug some of the bleeding vessels. Others propose that heat released by the cement coming in contact with the bone might cauterize bleeding blood vessels.

Based on the results from that study, it did not appear that cementing the implant in place influenced how much blood was lost during the knee replacement procedure. Surgeons still have to plan for blood transfusions in patients having a total knee replacement but it won’t be because of the type of fixation used. Some other factor may yet need to be discovered.

Blood loss is a fact of life when surgery is done on any body part. Total knee replacements require cutting into the bone and that’s a major cause of blood loss. In an effort to reduce this problem, surgeons are studying what patient factors might be contributing to the bleeding. Is it the patient’s age? The way the tourniquet is applied to the leg? The patient’s sex (male versus female)?

Blood loss is measured by collecting fluid lost during and after the procedure. During the knee operation, a special suction unit (much like your dentist uses to remove fluid from your mouth) is used to collect blood lost. After surgery, special tubes called drains remain in the joint and transport fluid out of the joint.

Measuring blood loss isn’t exactly easy. The drains can’t collect all blood lost during this time. Fluid loss (including blood) is measured and a special formula applied to figure out how much was blood. At the same time, patients blood is tested for hematocrit and hemoglobin levels.

These two measures are another indication of how much blood has been lost. When the hemoglobin levels drop down too far, then a blood transfusion is ordered. Having patients donate their own blood before the operation for use during or afterwards is ideal. But sometimes (for various reasons) that isn’t possible, so family members are called upon to help out. Your blood may not be used if it’s not a match, but it will go into the blood bank to replenish the unit(s) donated by others that are used instead.

Fractures of the femur (thigh bone) are not uncommon and can happen in people who have had total knee arthroplasties, or replacements. In anyone, when the bone breaks just above the knee, it can be complicated to repair, depending on how the bone broke (clean break, crush, shatter) and how close to the knee it broke.

One method used to stabilize such a fracture is to use nails that are placed in the bone to stabilize it. However, when a patient has a prosthetic knee, it may not be able to accommodate the end of a nail or, as the nail is place in the bone, debris from the bone may go into the joint, causing problems.

There are ways to fix the bone, but the approach may be a bit more complicated than if the knee was the original one.

A shattering fracture can be difficult to repair. Unlike a “normal” break, where the bone snaps in two, a shattered bone leaves bits and pieces of bone and nothing to support the remaining part of bone.

A shattered fracture cannot be just casted – surgery is needed to clean the area out and then stabilize the area. It is important to be sure that all bone fragments are removed from the body as they could cause problems later on. For stabilizing the bone, this usually mean attaching plates to the bone to strengthen and support it, but screws and nails may be used as well.

Anterior cruciate ligament (ACL) reconstructive surgery does require some intense and often lengthy rehabilitation to restore normal joint motion, strength, and proprioception (sense of joint position). All of these components are necessary for a strong, balanced joint that remains stable under pressure and doesn’t give way with the first uneven load placed upon it.

But there’s more to it than that. Studies show that the risk of developing osteoarthritis in the involved knee is much higher when muscles such as the hamstrings along the back of the thigh and knee and quadriceps along the front of the thigh are weak, tight, or imbalanced (one group is stronger than the other). Uneven joint loading can occur when any of these changes occur because of increased compression on some part of the joint.

When muscles are strong and contract when and how they should, the result is a smooth, coordinated motion. The muscles act as a shock absorber and dampen the forces of impact on the joint. This is especially important for athletes who rely on fast moves, sharp turns, and suddent shifts in direction. Patients who have a torn ACL and who are overweight or older than 30 have some additional risk of developing arthritis. Following an active rehab
program from start to finish is important for everyone regardless of age or active participation in sports (recreational or competitive).

Persistent pain with kneeling is commonly reported among patients who have a patellar tendon-bone graft to replace the torn or ruptured anterior cruciate ligament (ACL). It’s one reason why many surgeons use the hamstring tendon as a graft instead.

The advantage of the patellar tendon graft is that it provides a stable joint that isn’t too loose or too tight. And studies show that patients with a patellar tendon graft have more normal knee flexion after recovery and rehab.

Kneeling pain is often still present up to 10 years after the procedure. It may become more tolerable over time making it possible to kneel for short periods of time. Protective knee pads can be used for extended periods of time while gardening, cleaning, exercising, or praying.

There are different types of pads available. Some can be placed on the ground under the knees while others strap on around the knees. Each person chooses the one that suits their activities best.

Follow-up studies are often necessary but there is truth to the old expression ignorance is bliss. What we don’t know won’t bother us. On the other hand, forewarned is forearmed applies here. Knowing there are subclinical signs of arthritis is a signal that it’s time to get busy.

Knee arthritis can be minimized with activity and exercise along with weight loss if you are overweight. Take measures now to protect your knees in this way. A strengthening program of exercises to balance out the hamstring muscles (behind the knee) and the quadriceps (on top of the thigh) is also important after ACL repair.

Even a small difference between these two groups of muscles can lead to compression and overload on the joint. And studies show that it may be muscular imbalances that lead to the development of arthritis in the first place.

A physical therapist can help you. The therapist can use a special device called an arthrometer to test joint laxity (looseness), a measure of joint stability/instability. Joint range of motion, muscle flexibility, and muscle strength can also be tested and restored to normal with a follow-up exercise program.

Consider this type of approach insurance against future problems and complications. Since we know that arthritis occurs in half or more of all patients who have had ACL surgery, it makes sense to take steps now to protect yourself from this potentially disabling disease.

You are right — studies show that half of all patients who have ACL reconstructive surgery develop knee osteoarthritis later. That’s especially true for the folks who have an injury severe enough to damage the meniscus (cartilage) along with the ACL. Researchers in the area of sports medicine are working hard to figure out why this happens. They hope to find risk factors that predict who will develop arthritis and then perhaps modify those risk factors.

Based on what we know so far, it looks like delays in surgery should be avoided. The sooner surgery can be done following the injury, the better. Reconstructing the ruptured ligament before further damage can be done to the joint surface and joint cartilage may be beneficial. A preoperative program of patient education and strengthening exercises is a good idea. The physical therapist will show you how to avoid dangerous sideways and rotational movements that can add insult to injury.

There is some evidence that the type of graft material used to reconstruct the ruptured ligament can make a difference. Right now, it looks like the hamstring graft is a safer bet when trying to avoid arthritis later. The exact reasons for the difference in results between patellar tendon grafts and hamstring grafts are not clear yet. Surgery should also include repair (not removal) of any damaged cartilage whenever possible.

After surgery, every effort should be made to ensure restoration of joint motion and balanced muscle strength between the hamstring muscles along the back of the leg and the quadriceps muscle along the front of the leg. By participating in a pre- and post-operative physical therapy program, it is possible to improve balance, strength, and stability. At the same time, such efforts may help prevent additional damage to the joint that can ultimately contribute to the development of arthritis later.

Hamstring injuries are very common among young and old athletes alike. The hamstring muscle along the back of the thigh is made up of three parts: semitendinosus, semimembranosus, and biceps femoris. Hamstring strains and tears can cause scar tissue that puts the individual at risk for another injury. And often that second injury occurs within two weeks of returning to their full activities after only a short period of rest and recovery. And the second injury is more severe and more disabling. So you are right to be concerned enough to find some answers.

A recent update on the care and rehab of hamstring injuries has been published by a group of physical therapists from the University of Wisconsin. After reviewing all the studies and data available so far, combined with their own clinical experience, they propose a three-part recovery program for hamstring strains.

Phase 1 starts with low-intensity, pain free exercises designed to minimize pain and reduce edema (swelling) while helping form a nice, clean linear scar. The hamstrings are not stretched in order to avoid a thick scar and even contraction of the hamstrings is limited to painfree motions to encourage muscle healing. All exercises prescribed during this period must protect the muscle while it is remodeling during this early healing phase.

The patient is slowly progressed from phase one to phase two. Fiber repair is still an important phase of recovery during this portion of the rehab process. The hamstrings are not yet lengthened to their end range until strength is restored. Exercises are done that will gradually lengthen the muscle and overstretching is avoided. When full strength is present without pain and there is full motion, then phase three can begin. In this final phase, the focus is on fine-tuning everything needed for return-to-full activity and for those who are involved in sports, full participation in sports activities.

Specific exercises to help the athlete return-to-sport and the best timing for introducing that phase of rehab are suggested. The athlete will need to work on agility, sport-specific drills, and quick directional and postural changes. Muscle testing is done by the therapist to determine when the athlete is ready to progress to this last phase of rehab. They must have enough strength and stability to carry loads required by repetitive motion and needed to carry out those motions with speed. In order to return to full sports participation, they must have full strength and motion without pain and function near maximal speeds without pain.

You may not need to go this far yourself but it’s important that your flexibility, motion, strength, and coordination are fully restored to help you maintain your good recovery without a second injury. A physical therapist can help you reach these goals and evaluate the likelihood of a reinjury. With any rehab program, preventing that second injury is the bottom-line.

The jury is still out on the debate over stretching as a means of preventing hamstring injuries. There is some evidence that prolonged, daily stretching can help prevent injuries. It’s the quick, 10-second before activity stretching that doesn’t seem to really benefit athletes. And most of the studies have been done on athletes, so we really don’t have any data based on gender (male versus female) or age (younger versus older) or other factors.

The fact that stretching helps people feel good shouldn’t be discounted. Any movement improves circulation to the muscles (and joints) and has value in that alone. Stretching helps maintain full, pain free motion as well as improve posture and these are believed to be important factors in injury prevention.

Right now, the available evidence points to the use of exercises that emphasize eccentric muscle contractions as the best way to prevent hamstring injuries. Eccentric exercise starts with the muscle at its most shortened position (fully contracted) and then slowly releases the muscle to its fullest lengthened position.

Other suggestions for a prevention program include improving neuromuscular control of the entire lower half of the body. This includes core training to stabilize the lumbopelvic area, postural exercises to stabilize the trunk — especially while running or moving, and movements like high stepping, explosive starts, and forward-falling running drills.

More research is really needed to fully identify ways to prevent hamstring injuries. Perhaps there is an optimal way to stretch the muscle. Eccentric training is one way to balance out the strength component. There may be other methods equally important. Physical therapists are focusing on this problem and conducting specific research to help predict who is at risk for hamstring injuries, why, and what to do to prevent it from happening.

The question of the safety of leaving metal plates, screws, wires, and pins inside people’s bodies after surgery to fix fractures and other types of bone damage remains a largely unanswered one. Even with the research that’s been done, we don’t have any idea how much metal debris in the bloodstream or embedded in the nearby soft tissues is acceptable and/or safe (or unsafe).

A lot of studies in this area have been done on mice and rabbits. The results aren’t conclusive enough to provide guidelines for humans. Clearly, there are certain situations in which some patients are at greater risk from these implants. For example, the larger the surface area exposed to the implant, the greater the exposure and increased risk of metal debris entering the bloodstream.

Intramedullary pins or nails such as you have do show the highest risk of metal released into the body. Some metals are more biocompatible (e.g., titanium is better than stainless steel). But even these metals are not without some reactions and responses within the body.

Accumulations of debris are more likely when the implant is rubbing against another surface. This wearing or rubbing phenomenon is called fretting. A stable implant in good position and alignment will have minimal fretting.

Your surgeon may want to monitor your situation in order to see if the amount of metals detected in the blood are staying steady or increasing. Even with removal of the fixation device, it can be months up to a year or longer before changes are seen in your blood levels.