FAQ Category: Knee

Anterior cruciate ligament injuries can be repaired, but more often are reconstructed. In a repair procedure, the torn ligament is stitched back together and reattached inside the joint. Reconstruction involves removing the old, damaged ligament, harvesting some tendon tissue from someplace else, and using it to replace the ruptured ligament.

There are two common reconstructive procedures used today. In both, the surgeon removes a portion of the patient’s own tendon tissue to use in replacing and rebuilding an ACL replacement. Donor tissue may come from the patellar tendon or from the hamstrings tendon. In the case of the patellar tendon graft, the donor tissue comes from the front of the knee where the quadriceps muscle inserts into the bone just under the kneecap at the tendon-bone interface (that’s where the tendon inserts into the bone). For patients having a hamstring graft procedure, tendon tissue is taken from the hamstring muscle behind the thigh.

The surgery can be done arthroscopically as an arthroscopically-assisted minimally invasive procedure. That means the surgeon only needs a small incision to enter the joint. New surgical tools allow the surgeon to see inside the joint without making a large incision like you had. With less disruption of the tissue, wound healing is faster and cleaner. The result is the kind of scars you observed in your son’s friend’s knee.

But even with today’s more modern techniques, there are some patients who end up with a less than cosmetically pleasing scar. Infection can delay healing and create more scar tissue than hoped for. And some people have the type of tissue that forms extra scar (fibrosis) creating a wider, thicker scar. Most, but not all, patients can expect the kind of result your young friend ended up with.

It sounds like you may have some defects in the articular cartilage of the knee. Articular cartilage refers to the fibrous structure directly over the bone protecting the joint and helping produce smooth gliding action.

Knee articular cartilage doesn’t repair well by itself. There isn’t a lot of blood supply to the area. So left untreated, patients with this problem often develop knee pain, early osteoarthritis, loss of function, and eventually disability. That’s why surgeons often recommend surgical repair sooner than later.

In the last 10 years, joint resurfacing techniques such as microfracture (MF) and autologous chondrocyte implantation (ACI) have been developed to address this problem. In the microfracture procedure, tiny holes are drilled into the joint surface to create bleeding and stimulate a healing response. In the implantation procedure, normal, healthy articular cartilage cells are removed from the patient and taken to a lab. In the lab, scientists use the cells to grow more cells — enough to fill the hole or defect in the patient’s joint and repair the damage.

Early intevention and treatment is often recommended for moderate-to-severe defects because the patients who have the best results have the surgery early after injury (within the first 18 months). Studies show that patients have up to three years from the time of injury to the time of treatment before it may be too late for a safe and effective repair using these techniques.

Regeneration of cartilage is less likely to occur when patients have had painful symptoms for long periods of time. Early treatment helps preserve the entire joint surface and prevents changes in the metabolism of cartilage cells that could otherwise spell disaster with joint degeneration and destruction leading to osteoarthritis.

It sounds like you are describing a two-step procedure called autologous chondrocyte implantation. Autologous means the surgeon will use chondrocytes (cartilage cells) harvested from healthy tissue along the outside rim of the joint where there is less load and less wear and tear.

The first-step is the arthroscopic inspection. The surgeon takes a look inside the joint to see what’s going on and make the diagnosis. At that time, chondrocyte harvesting can be done and the cells sent to a lab where they will be expanded enough to fill the hole. The cells are then placed in the hole and covered over with a flap of bone or tissue membrane to form a smooth joint surface.

The goal is to form a long-lasting repair that will hold up under normal load and wear. Painfree joint motion with a return to all former activities provides improved quality of life for the patient. Things can go wrong with any surgery. With this particular procedure, sometimes pain persists. Chronic swelling and overgrowth of cartilage can lead to crepitus (crunching sound made by rough joint surfaces rubbing against each other).

Long-term studies have also shown that the harvested and implanted chondrocytes when expanded tend to lose their ability to remain chondrocyte cells. They start to become unstable and lose their form and structure, a process called dedifferentiation. The end-result is joint breakdown again and early arthritis.

Researchers are working on a solution to this problem. One approach is called cell therapy. With cell therapy, the autologous cells are treated (processed) in a special way to preserve the cells’ ability to remain stable and unchanged after implantation into the knee. This cell therapy procedure called a characterized chondrocyte implantation (CCI) is a slight variation of the autologous chondrocyte implantation (ACI).

As you research this topic, form a list of questions for your surgeon. The surgeon will be able to answer your questions based on factors such as your age, activity level, type of knee joint damage, and length of time from injury to surgery. The surgeon can speak from personal experience as well based on observed or reported adverse and/or long-term effects of this procedure for your type of injury.

Microfracture is a repair technique used for small defects in the articular cartilage of the knee. Articular cartilage covers the joint surface and makes it easier for the joint to slide and glide during movement. Osteochondral autologous transplantation (OAT) describes the removal of a plug of full-thickness articular cartilage along with a bit of the underlying bone it is attached to.

Autologous chondrocyte implantation (ACI) is the implantation procedure. The surgeon removes a bit of normal, healthy articular cartilage and sends it to the lab where the cells are expanded and multiplied and then reinjected into the defect. Both of these procedures are considered restoration (rather than repair) procedures.

The decision about which one to choose is usually left up to the surgeon. Sometimes he or she won’t know what approach to take until the area has been debrided (cleaned up and prepared for the repair or restoration). That’s when it’s possible to get a good look at the size, shape, and location of the defect.

There are some guidelines about when to use each technique. For example, small lesions respond well to the microfracture technique. But anything over 2.5 cm2 may require a restorative technique. The osteochondral plug is used for small, but deep lesions. The implantation with chondrocytes harvested from the patient and expanded in the lab may be best for larger but more shallow defects.

Your surgeon will go over the best choice for you and the factors affecting that decision as well as expected outcomes based on current evidence provided by published studies so far. The surgeon will have to take other factors into consideration when selecting the best procedure for you. Younger patients and/or athletes who expect to return to full sports participation seem to respond well to restorative procedures.

There is still a need for future studies to examine durability of these various techniques. For example, how long do the results last? Do some techniques hold up better than others? If so, why? What patient factors or types and sizes of defects affect the final outcomes?

Surgeons are advised to do a thorough preoperative evaluation before doing any kind of surgery, but especially an osteotomy where getting just the right amount and type of correction is necessary for a successful result. It may seem like a simple procedure but it takes quite a bit of technical skill, precision, and attention to detail.

A complete patient history will be taken during the medical interview. Your symptoms (including pain, difficulty walking, restricted function or activities) will be discussed at length. Pinpointing the cause of the problem is an important part of the treatment process. The surgeon will take a look at the areas above (hip and spine) and below (ankle and foot) the knee. Range of motion, ligament stability, and strength will be evaluated.

Imaging studies will be ordered such as full standing (weight-bearing) hip-to-ankle X-rays. Dynamic movement analysis and MRIs help show how you move, as well as assess the status of the joint ligaments, cartilage, and other soft tissue structures. Any instability, weakness, or damage to these areas can affect what’s going on in the knee now and affect how the knee will respond to the surgery.

All of these tests provide the surgeon with information about what’s wrong and how to fix it — how much correction should be made? How should that correction be done? What should be left alone? It’s not just a matter of removing a piece of bone, it’s also important to make sure the joint moves normally, remains stable and won’t dislocate, evens out the weight-bearing load across the joint so other problems don’t develop, and restore normal pain free motion.

So, if your surgeon is insisting on a barrage of preoperative tests that don’t make any sense to you, don’t hesitate to ask the benefit of each one. Most likely you’ll find you are in the hands of a thorough, capable, and meticulous surgeon — just the kind you want for a procedure like this.

You may have a condition called bipartite patella. Patella refers to the knee cap. It is exactly as you described. The cartilage that makes up the patella doesn’t ossify (harden) and form one smooth unit. Instead the person ends up with two or even three separate pieces (fragments).

Treatment is only required when the knee develops pain that limits function. Bracing is used along with rest and nonsteroidal antiinflammatory drugs (NSAIDs).

The brace supports the patella by immobilizing the knee and limiting flexion (bending). The brace is meant to stop the uneven pull on the patella from the quadriceps muscle (along the front of the thigh). The therapist will probably give you some stretching exercises that should also help.

Most people respond well to this type of conservative care. It may take several months to resolve the painful symptoms and restore full function.

Snapping knee syndrome refers to a snapping, popping, or clicking that occurs when the meniscus (knee cartilage) is pulled out of place inside the knee. To understand this better, a little review of meniscus anatomy might be helpful.

Most of the time, knee meniscus (menisci is the plural form of the word) has a standard C-shape. Placed on either side of the knee (medial for the inside/lateral for the outside), it forms two horseshoe-like structures to support the joint and provide smooth movement. Usually, the menisci are even, symmetrical and about the same thickness and width throughout.

But like all things in the human body, there can be differences in the size, shape, and structure of the menisci. Unusual meniscal shapes in the knee are called discoid meniscus. They are most common in the lateral meniscus seen in young children and they can be present in one or both knees. They can create instability that can result in injury from trauma. And it’s the child or teenager with a discoid meniscus who seems to end up with snapping knee syndrome most often.

The discoid meniscus, instead of being a curved crescent shape, tends to be block-shaped. The discoid meniscus is thicker than normal but the fibers that form the meniscus tend to be disorganized and form more of a haphazard pattern. They are larger than usual — large enough to cover the entire lateral side of the joint (the normal lateral meniscus covers up to 80 per cent of the surface).

Usually, the normal meniscus is held in place by a series of ligaments. But in the discoid meniscus, the absence of some of these ligaments allows the meniscus to move around. That excess movement called hypermobility pulls the meniscus out of place, creating an unstable joint and causing a snapping, popping, or clicking sensation called the snapping knee syndrome.

At first the snapping or popping seems to occur off and on — usually when the knee is moving from a flexed or bent position to an extended or straight position. Pain with movement and/or activity accompanies the snapping as the child gets older (around eight to 10 years of age). Discoid menisci that aren’t injured or that do not cause pain and/or instability are left alone.

But if an injury occurs and surgical repair is advised, then an arthroscopic approach is possible. The meniscus is reshaped and smoothed down, a procedure called saucerization. The goal is to create a stable, yet functional, meniscus. There is some concern that the remaining discoid meniscus won’t function properly because of its abnormalities, but studies done so far have shown that children seem to adapt. Long-term studies are needed to see what happens over time.

Pain control after total knee replacement is an important postoperative goal. Surgeons have found that injecting a numbing agent in and around the joint work well in reducing the need for narcotic drugs after surgery.

Adding a steroid to the injected fluid may help control inflammation. But there’s an increased risk of infection with steroids and the possibility of an allergic reaction. It’s not entirely clear that adding a steroid is really needed. A recent study from a well-known clinic specializing in joint reconstruction studied the question of whether adding a steroid gains patients any additional pain relief.

They compared two groups of patients having a total knee replacement. One group had the injection with the steroid (steroid group). The second group had the standard injection without the steroid (no-steroid group). No one in either group knew what type of injection they were getting. Their surgeons didn’t know what type of injection was being given. That research method is called a double-blind study.

All surgeries were performed by one surgeon who had advanced training in joint reconstruction. A periarticular approach was used for all injections. This means a little bit of the contents of each syringe was squirted around the knee ligaments where they attached to the joint, around the synovium (lining of the joint holding lubricating joint fluid), and along the back of the knee where the joint capsule (fibrous cartilage) is accessible.

Results were measured by looking at levels of pain, how much narcotic medication was needed/used during hospitalization, and how long each patient stayed in the hospital. They also measured range-of-motion of the knee and performed a test called the Knee Society score to gain an idea of knee function. These two tests of motion and function were done before and after surgery. Any problems or complications were recorded.

The authors thought the steroid group would do better with shorter hospital stays, improved motion, better function, and no real increased problems afterwards compared with the no-steroid group. What really happened was the steroid group got out of the hospital faster, but there wasn’t any difference in their pain levels, joint motion, or function. And there were some serious complications in the steroid group that did not develop in the no-steroid group. Each of those patients had unique circumstances contributing to the complications. The role of the steroid in those complications wasn’t clear, so can’t be ruled out entirely.

The authors conclude that adding a steroid to the injection given during total knee replacement surgery isn’t necessary. There was no clear benefit to it and safety concerns remain. Comparing the results of this study with other similar studies showed the authors that the other medications used in the no-steroid group are really effective and better than steroids at controlling pain.

Be sure and talk with your surgeon about your history and concerns. Reviewing in advance any potential problem areas can help save you worry and possibly reduce the risk of complications.

Research has shown that better pain control immediately after a total knee replacement reduces time in the hospital (and costs), improves function, and gives an overall improved result for the patient. Surgeons have gradually increased the use of drugs to control pain so that it is now common to follow a multimodal pain-control protocol.

Multimodal means many ways or methods to achieve pain control. This protocol started with periarticular injections (around the joint) of a numbing agent. That worked well but in order to reduce the need for narcotic drugs after surgery, intraarticular injections (right into the joint) with the same numbing agents was added. Then a steroid was added to the injection to help control inflammation.

Nurses who will care for you during the early post-operative period and physical therapists working with you in rehab will encourage you to stay ahead of the pain. Waiting until it is unbearable is not a good idea because pain that intense will keep you from moving the knee and getting out of bed to walk. All of those activities are important in preventing complications and improving outcomes.

It’s good that you let your physician know your thinking on this before surgery. Likewise, it’s good for you to know the rationale behind the use of pain meds. Some hospitals and clinics are offering alternative solutions to pain control such as acupuncture/acupressure, Reiki, massage, BodyTalk, hypnosis, and homeopathic pain remedies. Ask your surgeon if any of these are available in your area.

The physical therapist can also provide you with a little device called transcutaneous electrical stimulation (TENS) to help control pain. Electrodes placed around the surgical site provide a buzzing sensation that can sometimes override pain messages. Once it’s set by the therapist, you can change the level of sensation for optimal comfort.

Be an informed consumer. Find out what your options are ahead of time. See what might work best for you given your goal of minimizing the use of medications.

Osteotomy is a surgical procedure designed to realign the knee and even out the weight-bearing forces from side to side. A wedge-shaped piece of bone is removed from one side of the bone. Then the bone above and below the space is adjusted to correct the joint alignment. The two sides of the bone can be held open with a special opening-wedge metal device screwed into the bone. Or the two sides of the bone can be collapsed down toward each other in a closing-wedge procedure.

Once the joint is realigned to create a more normal load distribution, painful symptoms go away, and the knee is stable again. The best use of this procedure is for patients who have abnormal joint alignment and uneven weight-bearing that has led to unicompartmental arthritis on one side of the joint.

Usually the medial side (or compartment closest to the other knee) is affected but lateral unicompartmental arthritis can develop instead. The type of unicompartmental (one-sided) arthritis that develops is based on how the knee is put together, where the alignment problem is, and how the uneven load affects the joint.

In the past, osteotomies were more commonly used with older adults. But their use in younger adults has become the focus of closer attention in the last few years. New, updated techniques used to perform osteotomies make this procedure one to consider for younger, more active patients with unicompartmental knee arthritis.It can delay the need for a knee replacement by as much as 10 years and make it possible for you to remain unrestricted in your physical activities during that time.

The verdict is in on the subject of meniscectomy (removal of the meniscus) — don’t do it unless it’s absolutely necessary. And sometimes there is no way around it. But whenever possible, surgeons repair the damage and save as much of the natural meniscus (knee cartilage) as possible.

But now that you find yourself in your current situation without the meniscus and with the start of arthritis, looking for options is a good idea. And the allograft meniscal transplantation has been around for more than 25 years, so we have some data on how it holds up.

Allograft means the patient is receiving meniscal tissue donated by someone else (after death). The menisci are harvested and preserved by freezing them until needed. The patient receiving the graft is carefully tissue-typed to find a match with donor (allograft) tissue.

A study from the Netherlands of long-term outcomes showed an overall failure rate of the allograft procedure of 29 per cent. That’s almost one-third of the total group. Failure meant the graft had to be removed surgically. Graft failure occurred four to 14 years later, so you can see the graft did buy the patients some time before having a total knee replacement. And scores from the tests showed that there was a significant improvement in pain and function from before to after the allograft procedure. So, the procedure may have failed, but all was not a complete loss.

Delaying the need for a total knee replacement is one important advantage offered by allograft meniscal transplantation. The graft doesn’t last forever but the survival rate of the transplanted tissue is enough to delay major surgery (i.e., total knee replacement). And that’s good news because knee replacements don’t last forever either. And for younger adults such as yourself now developing degenerative arthritis, having a stop-gap measure between meniscectomy and joint replacement buys some pain free time with improved daily function.

The meniscus is one of two types of cartilage in the knee that helps stabilize, protect, and improve knee function. The second type of cartilage is called articular cartilage. The articular cartilage is right next to the joint surface. It provides a smooth surface for movement of the bones against each other.

The meniscus is next to the articular cartilage between the femur (thigh bone) and the tibia (lower leg bone). These two bones connect together to form the knee joint. The menisci support the knee joint, help distribute and transfer the load, and provide nutrition and lubrication to the joint. Without it, the concentration of force into a small area on the articular cartilage can damage the joint surface. Research clearly shows early osteoarthritis from joint degeneration is to be expected.

There are different ways to approach the treatment (and prevention) of this type of joint degeneration after meniscectomy. One of those has been around for the last 25 years: the allograft meniscal transplantation. Allograft means the patient is receiving meniscal tissue donated by someone else (after death). The menisci are harvested and preserved by freezing them until needed. The patient receiving the graft is carefully tissue-typed to find a match with donor (allograft) tissue.

Not everyone can have this procedure. Research shows results are best when it is used for younger adults (less than 50 years old) who have an intact anterior cruciate ligament (ACL). The ACL is needed for good support and stability. Without a healthy ACL, the meniscus is subject to even higher demands. The allograft is more likely to detach and fail when the knee is unstable because of a deficient ACL.

The ACL should be repaired first before doing the allograft. Normal knee alignment is necessary for a good result. The allograft is done when meniscectomy patients develop painful and limiting unicompartmental arthritis (affecting one side of the joint). There is some evidence to suggest the earlier this procedure is done, the lower the failure rate. But timing is important because they don’t last forever.

Talk with your orthopedic surgeon about your options. He or she may have some ideas about what might work best for you. A strengthening program for the muscles around your knee is a good idea to help support and protect the joint. Improving kinematics (how the knee moves) and proprioception (the joint’s sense of position) may help prevent uneven or unnecessary wear and tear. A physical therapist can help you find the right program of exercise for strength, flexibility, and function.

Knee pain is a very common problem in athletes who run, jump, and/or participate in sports that require these movements. Many athletes develop a problem called patellofemoral pain syndrome (PFPS) as a result. This painful knee problem can be chronic and prevent full participation in sports activities because of the pain. Anything that requires knee flexion (squatting or bending) seems to be particularly problematic.

Most of the time, there are anatomical and postural alignment reasons for PFPS. Some are modifiable (can be changed), while others cannot. Factors that can’t be changed with taping, bracing, shoes, exercises, or concentrating on changing movement patterns are called nonmodifiable.

Military recruits have been the subject of several studies involving PFPS. These young men and women are usually in fairly good shape when they enter the program. They participate in the same physical conditioning and sports activities making it easier to compare those who develop PFPS with those who don’t. Additionally, they aren’t overweight, so that’s one factor that can be eliminated.

A recent study of over 1500 naval academy freshman reported fewer students with PFPS than is commonly reported in the literature studying other (nonmilitary) athletes. The researchers weren’t specifically looking for reasons why this was so. They suggested that some recruits might adopt a tough-it-out attitude and ignore the pain. Others might learn ways to change how they do activities that cause pain. These compensation strategies might reduce the pain or at least make it possible to withstand the pain. Going to the troop medical clinic or asking to see a doctor might be perceived by this group as unacceptable. So, in fact, they may have just as many problems as your freshman, they just don’t report it.

Even so, the authors of that study suggested a good place to maybe prevent knee problem is strengthening the quadriceps and hamstring muscles and teaching proper techniques for activities that are painful. Active young adults such as military recruits and athletes can be assessed before engaging in physical activities that could potentially lead to the development of patellofemoral pain syndrome. Anyone with modifiable risk factors can be trained to change the way they move and perform dynamic tasks such as knee flexion and jump/landing. Changing the hip angle (less internal rotation) and knee angle (more knee flexion) might make a difference in these active groups of people.

Patellofemoral pain syndrome (PFPS) affects one out of every four active individuals, making it one of the most common knee problems among athletes and military recruits. What causes this problem? Well, it can be fairly complex. Usually there isn’t just one reason why people develop PFPS.

The patella, or kneecap, can be a source of knee pain when it fails to function properly. Alignment or overuse problems of the patella can lead to wear and tear of the cartilage behind the patella. This produces pain, weakness, and swelling of the knee joint. Several different problems (including PFPS) can affect the patella and the groove it slides through in the knee joint.

It is believed that PFPS occurs because of altered biomechanics between the patella and the femur (thigh bone). The patellofemoral joint is where the kneecap moves up and down over the lower end of the femur. If the patella doesn’t track up and down over the femur where it should, uneven wear and tear can occur. The protective cartilage behind the patella can get torn and shredded. Patellofemoral pain syndrome is most noticeable when kneeling, squatting, or during other activities that require bending the knee. That’s because altered hip and knee motion increase the pressure from contact between the patella and femur during these motions.

That’s one side of the equation. The other side involves the foot, such as in your case. Pronation/i> of the foot (toward a flat-foot position) alters the biomechanical relationship between the foot and knee. A simple drop in the arch of the foot shifts the weightbearing load on the knee toward the medial half of the joint (side closest to the other knee). Repetitive knee motions will increase pressure and load on that one side more than the other — potentially leading to patellofemoral syndrome or even knee arthritis later in life.

Correcting the foot position is important, but it may not be the only problem. Research shows that the hip angle as well as any muscle weakness or imbalance anywhere in the leg can contribute to patellofemoral pain syndrome. But there’s nothing wrong with making one correction and seeing how you feel. Having someone such as an orthopedic surgeon or physical therapist evaluate your posture, muscle strength, and kinematics (how the knee moves) is a good way to identify early on other problems that could be corrected as well, thus possibly reducing your risk for other knee problems or a recurrence of the PFPS.

Research has shown that corticosteroids injected into the joint work for reducing knee pain caused by osteoarthritis. But the pain reducing effect only lasts about one week. Steroid injections offer short-term pain relief but they aren’t advised for more than that.

There are different steroid medications available for injection such as betamethasone, methylprednisolone, and triamcinolone. A review of the available studies published so far suggest that triamcinolone appears to outperform the other drug choices as well as a placebo (injection without the effective medication). More research is clearly needed in comparing different steroid injections, the timing and dosage of the injections, and factors that predict which patients are most likely to respond.

Fortunately, even though steroids only give short-term pain relief, there are other effective treatments patient can use as well. Physical activity and exercise, nutritional supplements, antiinflammatory drugs, braces, topical creams, and if necessary, surgery are all acceptable treatment choices.

Finding the most optimal single treatment or combination of treatments may be an individual decision. But it is one that is best made with the help of a physician who treats arthritis patients on a regular basis. If your neighbor has not been to see a doctor for a proper evaluation and diagnosis, then that is the next best step.

Steroid injection into the knee is a well-known effective short-term method of getting control of disabling pain and quickly improving function. Since the effects wear off after seven to 10 days, it’s not meant for long-term pain control. But it can help a person get on a pain control program with follow-up using nonsteroidal antiinflammatories (NSAIDs) and analgesics (pain relievers like Tylenol).

Studies have investigated whether or not physicians can really deliver the injection into the joint space. The overall conclusion of research looking at this factor is that properly trained medical staff can deliver the medication into the knee joint with no problem at all. Other joints such as the hip or shoulder may be more problematic requiring the use of fluoroscopy, a special real-time (3-D) X-ray that allows the surgeon to see what her or she is doing.

Complications such as infection can happen after any surgical procedure. The surgeon and his or her staff do everything possible to avoid this problem, but it does happen. Besides the obvious reasons such as inadequate sterile technique during surgery, efforts are underway to look for risk factors among patients that might predict post-operative problems of this type. The goal, of course, is to reduce (eliminate!) such complications.

According to a large study done in the state of New York just looking at outcomes following anterior cruciate ligament (ACL) reconstruction, there is a fairly low rate of problems. Only 2.3 per cent of the 70,500 patients had to be readmitted within 90 days of the surgery. Infection was one reason for those hospitalizations. But medical reasons unrelated to the orthopedic surgery such as heart attacks and appendicitis accounted for some as well. Knee stiffness and need for additional rehab was another reason for further treatment.

Watching these same patients for a full year revealed a slightly higher rate (6.5 per cent) of subsequent knee surgeries. One-third of those surgeries was for another ACL reconstruction. The rest were for other problems such as scar tissue or meniscal (cartilage) tears. About 11 per cent of the group had infection requiring a second surgery. ACL reconstruction is considered a safe and effective procedure, but it is not without its problems for a few patients.

Statistical data on orthopedic surgeries performed in the U.S. show that anterior cruciate ligament (ACL) injuries are common. The number of ACL surgeries is on the rise and not because there are more surgeons around to do the surgery or because there are more people in general (as measured by the U.S. census). More people are active and involved in sports and activities that can lead to trauma and knee injuries.

Knowing that ACL reconstruction is a common procedure, it’s important to look at the results. How safe is the procedure? Do the results hold up over time? How many patients end up having complications or another surgery later? In a recent study, a statewide hospital database from New York was used to gather information on the results of ACL reconstruction. In this study, they measured 1) number of ACL reconstruction surgeries done between 1997 and 2006, 2) how often these patients need another surgery later, and 3) risk factors to predict readmission or second surgeries.

Using hospital identification numbers and physician license numbers, the researchers were able to calculate annual volume for the 263 facilities and the 1513 surgeons involved. Basic information about over 70,500 patients who had an ACL reconstruction was collected (e.g., age, sex, type of insurance coverage, and the presence of other health problems).

As you have heard, age was a big factor. The patients who had the highest readmission rate (within 90 days) were older men (more than 40 years old) or those who had other health problems. But there was one other important factor. Patients were also more likely to be readmitted for problems if they were operated on by a lower-volume surgeon in a lower-volume hospital. Low volume was defined as the surgeon performed less than six ACL reconstructions per year in a hospital where less than 24 total procedures of this type were done each year.

The risk of having a subsequent ACL surgery (within one-year) was highest among patients who were younger than 40 (especially those who were younger than 20 years old). That may be because they are more active and less likely to follow guidelines on restrictions following surgery. One other risk factor for later problems requiring additional surgery was having a meniscectomy (meniscus removal) at the time of the initial ACL reconstruction procedure.

Age is an important factor, but it isn’t the only one. The patient’s general health, the surgeon’s experience, the presence of other knee injuries, and patient activity level must all be taken into consideration. Anterior cruciate ligament reconstruction is a technically demanding procedure. The complexity of the procedure is a risk factor of its own. Surgeon and hospital volume are important but there are many other possible risk factors yet to be explored when trying to isolate what it is that causes patients to require readmission or subsequent surgery. Future studies are needed to look at the many possible risk factors.

This type of knee replacement is designed to replace only the portions of the joint that are most damaged by arthritis. The operation is less invasive than a full knee replacement. There are significant advantages, especially in younger patients who may need to have a second artificial knee replacement as the first one begins to wear out. Removing less bone during the initial operation makes it much easier to perform a revision artificial knee replacement later in life.

Studies have shown that many patients experience continued muscle weakness after unilateral knee replacement. The reasons for this aren’t entirely clear. The incision, cutting through muscles, and surgical trauma may contribute to loss of muscle power. Loss of muscle bulk (called atrophy) from favoring that leg before surgery may also be a factor. Anytime there’s muscle weakness with loss of muscle power, there’s a decrease in muscle coordination. You need both strength and coordination to recover from a stumble or sudden loss of balance.

If you aren’t having any other symptoms, you may benefit from an exercise program designed to regain strength, coordination, and balance. The first step may be to check back with your surgeon. If all looks good with the implant, then a physical therapist may be the best one to help you out with this problem. A specific program of exercise focused on the problem areas may be all you need. With a few sessions, you may be well on your way to having solved the problem (and preventing future problems from falls and injuries from falls).

Perhaps, but probably not without a little help. Studies show that a loss of muscle strength and power are typical after unilateral knee replacement (UKR). UKR refers to the placement of an implant on one side of the knee (either medial on the inside half of the joint closest to the other knee or lateral on the outside of the joint). Walking speed, recovery from falls, and stairs can all be affected by persistent muscle weakness after this procedure.

The loss of muscle power affects muscles on both sides of the leg (front and back/extensors and flexors). It’s possible for the nonoperated (stronger) leg to compensate for the operated (weaker) leg when walking but it takes more muscle power than that for stairs. Stairs require the use of both sets of muscles and in both legs at the same time (the supporting leg and the moving leg).

It’s good that you haven’t just accepted this as the way it must be — you can improve your strength and get a normal stair-step pattern back. And it’s a good idea to address the problem now before it becomes even more long-term. All evidence to date suggests that your loss of strength won’t go away on its own — even after waiting months to years. You may need to consult with a physical therapist who can identify which muscles are affected and prescribe the right exercises to help with full recovery. Until you get your complete motor recovery, you will be at an increased risk of falls and injuries from falls.