FAQ Category: Knee

You may be referring to autologous chondrocyte implantation (ACI). Autologous chondrocyte implantation refers to using the patient’s own cartilage to repair deep holes or defects in the cartilage. These type of full-thickness, large lesions of the knee occur most often in in active, high-demand patients such as athletes.

If you’ve already had surgery for this problem, you’ve probably had a debridement or microfracture procedure. Debridement removes any loose fragments and smoothes the cartilage surface of the joint. Microfracture is the drilling of tiny holes through the cartilage to the joint surface. This technique stimulates bleeding and sets up a healing response. Debridement and microfracture are considered first-line treatment approaches.

A third treatment option for first-line care of cartilage injuries is an osteochondral autograft transplantation. This involves harvesting a layer of cartilage and bone from a healthy area of the same patient’s joint and transferring it to fill in the hole. Any of these first-line treatment approaches work well for inactive or low-demand patients with small lesions. But for active patients with large defects, a different procedure might work better. That’s the autologous chondrocyte implantation (ACI).

To perform an ACI, the surgeon first removes healthy cartilage cells from the patient and sends them to a special lab where they grow more of the same type of cells. When there are enough cells to fill the hole, the surgeon performs the second part of the procedure. The hole is prepped for the new cells, which are then placed in and around the defect. The implanted area is then covered over with a patch of periosteum, the outer layer of bone (also harvested from the patient). The patch fits over the repaired defect like a manhole cover.

There are some potential problems with this treatment method. Removing cartilage cells and periosteum needed for the implantation always leaves the donor site at risk for subsequent problems. And the implanted chondrocytes don’t always fill in with good, solid cartilage. Sometimes, the new growth is just a fibrous type of cartilage. But there are some long-term studies that show it holds up for the majority of patients who say they would have the same treatment again.

Properly selected patients can expect the good results to last for many years as shown by this study. Patients older than 40 are less likely to have chondrocytes with active growth factors and more likely to have fewer new, healthy cartilage cells form.

Maybe what you need is a rehabilitation program to increase muscle strength and improve proprioceptive function. Proprioception is the joint’s sense of its own position. Tiny receptors inside the joint send messages to the brain whenever even the slightest change in position or movement occurs.

But any damage to the joint (either a traumatic injury or degenerative changes with aging) can decrease the joint’s ability to receive and respond to proprioceptive messages. The result can be instability like you are describing.

There can be other factors contributing to an unstable knee. Muscle weakness, ligament ruptures, and cartilage tears are possibilities. It’s probably a good idea to see an orthopedic surgeon who can evaluate your knee specifically. If there’s nothing specifically wrong, then a program of strengthening exercises with an emphasis on proprioception might be just what you need.

You’ll want to include exercises to strengthen the quadriceps (muscle along the front of the thigh), the hamstrings (muscle along the back of the thigh), and even muscles around the hip and ankle. Studies show that exercising in the seated position (nonweight-bearing) helps improve motion, strength, and function. But exercises done in the standing position or seated with the feet in contact with some form of resistance (weight-bearing) is even better.

With weight-bearing exercises, you will strengthen and improve proprioception. Those two things combined together can help improve stability and function and even help prevent falls. If your doctor clears you medically and there’s no need for more aggressive treatment such as surgery, then seek out the services of a physical therapist and get started. The physical therapist can help you find the right type and amount of exercises for this problem.

Someone who experiences stiffness that gets better with movement is probably experiencing some muscle involvement. On the other hand, people who feel good when first waking up but then stiffen up as the day goes by are more likely to be dealing with issues involving the joints.

Muscle weakness can sometimes be a greater problem than even pain — especially in older adults who have become more sedentary and deconditioned. The first thing is to have a medical evaluation. If she has stiffness everywhere, there may be a systemic reason for that. If she has osteoarthritis, there are medications and exercises that can help.

In fact, many studies have shown that even simple knee flexion and extension exercises do help with knee osteoarthritis. They improve strength and help the knee respond quickly to any change in position. The result can be less stiffness, faster walking speed, and a lower risk for falling.

When it comes to exercise, in any community, there are usually several choices for seniors. Local and public TV stations broadcast programs like Sit To Be Fit or Yoga for Seniors. Fitness centers, senior centers, the YMCA/YWCA, and other similar places often offer a wide range of exercise classes that might be suitable.

It may help to have a physical therapist evaluate your mother for specific areas of weakness for some spot strengthening. The therapist can set her up on a home program and offer rechecks weekly/monthly to make sure she stays on track and progresses her exercises appropriately. Even simple resistance and balance training at home can be very effective for a wide variety of benefits including reducing pain and stiffness while increasing strength and function.

Defects in the joint surface cartilage can stabilize if they aren’t in a location of load bearing. But most of these holes develop as a result of chronic stress and overloading. Small defects might not get worse if the person isn’t overly active. Chondral defects in older, more sedentary adults have a better chance of staying the same.

Keep in mind that the cartilage doesn’t have a natural blood supply that would set up a repair process. So, although the damage might not get worse, it won’t get better on its own. There are marrow stimulation techniques that have been developed to stimulate healing of full-thickness chondral defects. Full-thickness describes your situation where the damage extends down to the surface of the bone underneath the cartilage.

There are different ways to stimulate the bone marrow to produce new chondrocytes (cartilage cells). Drilling into the first layer of bone under the articular cartilage is one. Shaving the surface of the bone called abrasion arthroplasty is another and microfracture is the third method currently in use.

All of these procedures have one thing in common. They are designed to fill the hole or defect with tissue from the bone at the bottom of the defect. This can help set up the repair process needed. A clot forms that eventually turns into fibrocartilage tissue.

Your surgeon is the best one to advise you on the treatment of your knee. The location, size, and type of defect are all important factors to consider when establishing a plan of care.

Folfing (a combination of golfing and frisbee) is a popular outdoor sport for young and old alike. Even though you aren’t an athlete, having the physical ability to play a game or two of any kind with your children is important to your quality of life.

So, treatment is essential and usually does start with conservative (nonoperative) care. A rehab program supervised by a physical therapist may be just what you need. You will regain motion and strength. The therapist will also help you retune the receptors around the knee that register small changes in motion. This is important in preventing future injuries.

Whenever the anterior cruciate ligament is damaged, there is a risk for meniscal tears or cartilage lesions. The further you are out from the date of the injury, the greater your risk. If surgery is going to be needed, there is some evidence that it should be done within the first 12 months after the injury.

Once you complete your rehab program, you, the therapist, and the surgeon will have a better idea of what else (if anything) is needed. For now, the best approach is to follow your therapist’s plan of care diligently (daily) to get the best results. After that, you may want to make a follow-up appointment with your surgeon to re-evaluate your knee and your treatment plan two to three months down the road.

The meniscus is a moon or crescent-shaped fibrocartilaginous structure present on both sides of the knee (medial and lateral). Both menisci provide structural integrity and support to the knee when it undergoes tension and torsion. Athletes involved in pivoting, cutting, or sudden changes in direction are most likely to sustain an ACL/medial meniscus tear. This commonly includes soccer and basketball players and skiers.

As you have discovered, treatment of meniscal tears has indeed changed over the years from removal to preservation. Surgeons use arthroscopic methods to check the meniscus for damage. Any frayed edges are smoothed. Holes may be drilled with a tiny meniscus repair needle to stimulate bleeding and speed up recovery. The process of putting holes in the cartilage is called trephination.

The focus today is more on finding the best way to repair this structure. But at the same time, studies show that some menisci have very poor healing potential and may be better removed. The biggest factor in surgical success to preserve the meniscus appears to be location of the meniscal tear.

There are three zones in the meniscus that correspond to blood supply to the area. The outermost zone is the red-red zone. Here there is the greatest amount of blood flow and the best chance for success. The middle zone (between the red-red and white zones) is the red-white zone. The inner zone is called the red-white zone. Healing potential is the poorest for tears in this central zone.

Patients with less than normal meniscal tissue who are active may benefit first from a rehab program to strengthen the muscles around the knee. This approach helps increase knee stability and protect you from future injuries. If this treatment method doesn’t resolve your pain and other symptoms, then surgery may be the next step. If the tear cannot be preserved through surgical repair, then it may be necessary to remove the damaged area. Surgeons rarely remove the entire meniscus anymore.

The first step is to make sure you have a follow-up visit with your surgeon. It’s possible your knee pain is caused by something other than a failed meniscal repair. Meniscus (plural: menisci) in the knee depend on an intact and healthy anterior cruciate ligament (ACL). Without the ACL, forces on the meniscus increase up to 200 per cent. Assessing the status and condition of the ACL will be an important part of the exam.

Sometimes there are muscular weaknesses or postural imbalances that can contribute to knee pain. A trip to see your physical therapist may also be helpful. Restoring normal motion, proprioception (awareness of joint position), and kinesthesia (awareness of movement) are important after any knee injury, especially one that has involved a surgical repair.

It is also possible that your repair has failed and the meniscus has torn again. Studies show a higher than hoped for rate of failure after meniscal repairs. Failure of meniscal repairs increases with time from surgery. In those cases, a second surgery may be needed to remove any free-floating pieces of meniscus and smooth down any rough or frayed edges.

The menisci (plural for meniscus) are C-shaped strong cartilage that sit between the femur (thigh bone) and the tibia (lower leg bone). The menisci are sometimes referred to as the cartilage of the knee, but they are separate from the articular cartilage that covers the surface of the joint.

There are two parts to the meniscus: medial and lateral. Medial refers to the side of the knee closest to the other leg. Lateral is the side away from the other leg. The medial and lateral menisci of the knee work like a gasket to spread the force from the weight of the body over a larger area help the ligaments with stability of the knee. Without the menisci, any weight on the femur will be concentrated to one point on the tibia. But with the menisci, weight is spread out across the tibial surface.

The front portion of the meniscus is referred to as the anterior horn, the back portion is the posterior horn, and the middle section is the body. The posterior horn is an important anatomical feature. Without it, stress on the meniscus is enough to cause significant load on the joint. That’s when the degenerative processes speed up. A complete tear or rupture of the posterior horn is called an avulsion.

How often does it happen that someone ends up with a posterior horn avulsion of the medial meniscus? It was once thought that this was a relatively uncommon injury. But with the availability of MRIs, doctors have documented a much higher incidence than previously thought. Up to 28 per cent of all medial meniscal tears involve the posterior horn.

Treatment often depends on the patient’s age, intensity of symptoms (mild versus severe), and activity level. The goal is to protect the knee joint and prevent degenerative changes that end up as painful knee arthritis. For the older, less active adult, it may be possible to get by with some activity modifications, antiinflammatory drugs (or just pain relievers), and weight loss for those who are overweight.

When it looks like surgery might be needed, the patient has several options to choose from. If at all possible, the surgeon tries to save the meniscus. The goal is to restore the menisci’s ability to absorb stress and still support normal knee biomechanics.

Repair is preferred over removal. The meniscus is no longer routinely removed but rather reattached whenever possible. Rehab after surgery is important so if a patient isn’t willing (or able) to follow the surgeon’s guidelines, then surgery may not be successful.

If it’s not possible to repair the meniscus, then partial removal is considered. With complete removal of menisci that cannot be repaired, meniscal transplantation may be possible in a small, limited number of cases. Meniscal transplantation is referred to as a salvage procedure.

Many surgeons advise patients to complete a three- to six-month course of conservative care first before considering surgery. Those who can control their symptoms with a change in activity, pain relievers or antiinflammatories, and weight loss/management should do so for as long as possible.

Bone marrow stimulation techniques are used to treat a knee with a hole or defect in the articular cartilage. Articular cartilage is the rubbery, fibrous cartilage that covers the ends of bones to protect the joint. When the defect goes all the way down to the first layer of bone, it’s called a full-thickness defect.

There are different ways to stimulate the bone marrow to produce new chondrocytes (cartilage cells). Drilling into the first layer of bone under the articular cartilage is one. Shaving the surface of the bone called abrasion arthroplasty is another and microfracture is the third method currently in use.

If one of these methods doesn’t work, the surgeon can try another of the three approaches in hopes of a better outcome. Or you might be a good candidate for another treatment method called autologous chondrocyte implantation (ACI).

With ACI, normal, healthy cartilage cells (chondrocytes) are removed from a part of the knee joint that is not weight-bearing. They are taken to a lab where they are multiplied to form enough repair cells to put back in the defect and stimulate growth of the needed fibrocartilage. The cultured chondrocytes are injected underneath a special patch that has been placed over the hole.

However, it is important to know that there is some evidence that ACI after having a bone marrow stimulation treatment has a higher rate of failure. In fact the failure rate was three times higher in patients who had ACI after a failed bone stimulation surgery. Failure meant the patient still had pain limiting function, MRIs showing that the graft didn’t take, and/or surgery had to be done to remove the graft.

It’s not clear yet just what caused that high of a failure rate. At first, the scientists thought it was because patients developed thickening of the subchondral (first layer of bone under the cartilage), bony overgrowth, and/or the formation of subchondral cysts. They seemed more likely to have a poor outcome when this happened.

Deterioration and failure of the bone marrow stimulation may occur because the new tissue forms over a thick, protruding, and stiff subchondral base. Eventually that subchondral plate starts to degenerate.

But it’s also possible there are some patient-specific (unknown biologic) reasons for this failure that had nothing to do with having autologous chondrocyte implantation AFTER marrow stimulation surgery.

It may be best if you make a follow-up appointment with your surgeon to find out what’s next for you. Any of these procedures might be possible and highly effective. You don’t have to accept painful suffering without exploring a few other ideas first.

Right after your surgery, you will be seen by a physical therapist at least once (and often twice) a day. Exercises and movement to reduce swelling and pain and improve circulation and motion are often prescribed. When you go home, you’ll be given a home program to follow. The home exercise program will build on what you started in the hospital in terms of range-of-motion, strength, coordination, and endurance.

All indications are that you should follow those exercises (and expand upon them) for at least six months. For best results, continuing the exercises and advancing them as tolerated should be done for a full two years after a hip or knee replacement. Emphasis is placed on the hip abductor muscles (they help move the leg away from the body and stabilze the trunk).

Exercising once a day is the minimum. Twice a day is good. But incorporating a little bit of physical activity and exercise into each and every hour of the day is really ideal. Without overdoing it, you want to keep that joint moving and prevent the formation of any adhesions (excessive scarring).

Sometimes swimming can be very useful. The natural buoyancy of the water, the elimination of gravity and forces on the joint, and the warm temperatures make this an excellent treatment approach. A few days to a week after surgery, you’ll be able to do exercises (e.g., squats, step ups, walking without a cane or walker in the water) that wouldn’t be possible on land.

It’s a fact that knee injuries (and especially anterior cruciate ligament (ACL) tears) are common among athletes. Basketball, volleyball, and soccer players seem to be at increased risk. This is probably because the actions that predispose them to injury (pivoting, cutting, twisting) are used so often in these sports activities.

As to how quickly (and successfully) male versus female athletes return to sports after ACL surgery, there are studies that show females need more rehab than men. But there are just as many studies that report no difference between men and women in terms of test results or time to return to sport.

Other factors that might make a difference are age, motivation, type of rehab program, and previous injuries. Right now the evidence is fairly limited. But most athletes want to return to their sport as soon as possible. So, more sports scientists are looking into this question as well as looking at how fast athletes can be moved through the rehab protocol.

We can’t guarantee how things will go in the future. But some of the best minds in this country are discussing the state of our health care delivery system. They know that a little effort goes a long way in preventing a disabled system from breaking down altogether.

And the American Academy of Orthopaedic Surgeons has made it clear that the predicted growth in patient demand for joint replacements is going to outpace the number of surgeons available to provide them. Advanced technology and improved surgical technique has made joint replacement easier and safer than ever before. There are fewer risks and complications. This is especially true in the older population — another reason why joint replacements are becoming so popular. What’s the answer to this supply and demand dilemma? Some experts suggest that avoiding this problem is possible.

They say that policy makers need to increase the rate of reimbursement to surgeons for total joint procedures. Medicare keeps reducing how much they will pay while the costs of doing business in the health care world continue to rise. Another possible solution is to prioritize patients according to need and predicted outcome. What does that mean?

Well, we know, for example, that patients who have worse function before surgery tend to have poorer outcomes after surgery. Women and certain ethnic groups (e.g., Hispanic, African American) fall into this category. It may be a coincidence that these patients have worse function before seeking out a joint replacement. Or it may be that people in these groups delay treatment for too long. Lack of insurance, cultural issues, or less access to care may also be reasons for this delay. Getting them in for surgery sooner than later may actually improve their results.

All of this points to the need for education. First, for the policy makers responsible for determining reimbursement rates on surgical procedures. Then to aging adults who are starting to develop joint problems. With modified activity, strengthening exercises, and medications, the effects of osteoarthritis can be prevented and managed much longer. It may be possible to reduce the need for joint replacements (or at least delay surgery it without affecting the final results).

Your concerns are well founded. In order to stay fit and active, 30 to 45 minutes of exercise is recommended each day. For those who want to lose weight, 60 to 90 minutes of activity and exercise is needed. A strengthening program will help protect the joints from excess load and stress. Proper shoes, good posture, and avoiding repetitive motions are all helpful ways to protect the feet knees, hip, and spine — all contributing to good joint health. If you need help finding the right path, see a physical therapist. A therapist can help answer some of your questions, assess your musculoskeletal health, and steer you in the right direction.

Your gait (walking or running) cycle involves two main movements: stance and swing. Stance has several phases (e.g., contact, mid-stance and propulsion) but always involves having the foot in some contact with the ground.

Contact starts when the heel hits the ground. The knee is slightly bent just before contact. Just after contact, the foot pronates or rolls in. This allows the foot and leg to work together to provide a cushion that absorbs shock up the leg.

When the forefoot makes contact with the ground, the foot is flat. This is the start of the mid-stance phase of stance. During mid-stance, the foot and leg provide a stable platform for the body weight to pass over. The foot must not roll inward at this point or there will be too much movement and instability.

During mid-stance the other foot is in the swing phase (no weight on the ground at all). All the body weight is on the stance leg. That’s why mid stance is a time when lower limb is at increased risk for injury. Following mid-stance comes propulsion. Propulsion begins as the heel lifts. The big toe flexes, the arch lifts off the ground and the body is propelled forward. Anytime the foot is in the wrong position or does not function properly during the late mid-stance and propulsion phases of gait, there is an increased risk of injury.

Today’s running shoes are built to accomodate the stresses and strains put on the foot during mid-stance and propulsion. Improved shoewear and explanations for how they work may be why these terms seem new to you — they have become part of the focus of advertisers and running/training specialists.

You should have the orthopedic surgeon who performed the arthroscopic exam determine the cause of the problem you are describing. It’s possible you have a superficial skin infection. Or you may have the beginnings of a problem called complex regional pain syndrome (CRPS). Either way, early diagnosis and treatment is essential.

Skin infections are usually treated with topical and/or oral antibiotics. The symptoms clear up quickly within the first few days of taking the medications. Something more complicated like complex regional pain syndrome (CRPS) is not so quickly or easily treated. CRPS has various stages that last varying and unpredictable lengths of time.

Treatment depends on the symptoms and may include physical therapy, acupuncture, electrical stimulation, nerve blocks, and medications. The medications may be used for pain control, to improve circulation, or to interrupt nerve signals causing the painful symptoms.

Your physician is the best one to guide you — first in determining the correct diagnosis and then in providing a plan of care. Don’t hesitate to go in for a follow-up appointment as soon as possible.

The knee has two main ligaments that criss-cross and stretch between the femur (thigh bone) and the tibia (lower leg bone). These are the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). Working together, the two cruciate ligaments control the back-and-forth motion of the knee.

The ACL keeps the tibia from sliding too far forward in relation to the femur. The PCL keeps the tibia from sliding too far backward. They PCL also controls how much the tibia rotates externally (outward direction). Besides the ACL and PCL, there are other ligaments, cartilage, and soft tissues that surround the knee to help give it strength and stability.

There are two ways the PCL gets injured most often. The first is much like your situation — in a car accident. The force of the impact slams the passenger’s bent knees into the dashboard. This high-velocity injury pushes the tibia back underneath the femur. The shear force is enough to rupture the PCL holding the tibia in place.

A second mechanism of injury (more common with athletes) occurs when the foot is planted on the ground and the knee hyperextends. Hyperextension means the joint is as straight as it can be and then a force pushes it into even more extension, thus the term hyperextension.

Although many people seem to function fine without an intact PCL, there can be long-term problems that develop as a result of the deficient joint. Early arthritic changes are the most common problem. Knee instability is another. Instability is seen as chronic knee pain and episodes of giving way when the knee goes out from under you. Both of these problems tend to develop as people get older and experience weakening of the quadriceps muscle or degenerative changes in the other supporting structures holding the knee together.

The decision to have surgery can be complicated with many things to consider. Many surgeons advise their patients to try a more conservative approach first. A program of strengthening and conditioning often goes a long way in protecting the knee and preventing instability. Usually a three- to six-month course of nonoperative care is enough to show you if this approach can be successful.

Having a physical therapist evaluate you and set up the program is a good idea. That way the exercises and suggestions can be tailored to your specific needs. You will be able to progress through successively more difficult exercises in order to build strength, improve coordination, and develop endurance. Most of this can be done as a home exercise program. If you are still having problems at the end of that time, then it might be time to reconsider the pros and cons of surgery.

Much has been written about the evaluation and treatment of anterior cruciate ligament (ACL) tears. That’s because they are the most common knee injuries among athletes. Though less common, injuries to the posterior cruciate ligament are just as important.

To better understand how PCL knee injuries occur, it is important to understand some of the anatomy of the knee joint. Knowing how the ACL and PCL work together to maintain stability and normal function is a large part of determining the optimal treatment for each patient.

The ACL and PCL are the two main ligaments that criss-cross and stretch between the femur (thigh bone) and the tibia (lower leg bone). These two bones join together to form the knee joint. Working together, the two cruciate ligaments control the back-and-forth motion of the knee.

The ACL keeps the tibia from sliding too far forward in relation to the femur. The PCL is made up of two separate but adjoining bundles of fibers. Each bundle has its own specific function. These bundles work together to keep the tibia from sliding too far backward in relation to the femur. They also control how much the tibia rotates externally (outward direction). Besides the ACL and PCL, there are other ligaments, cartilage, and soft tissues that surround the knee to help give it strength and stability.

There are two ways the PCL gets injured most often. The first is in a car accident when the passenger slams his or her bent knees into the dashboard on impact. The force and speed of the knee against a solid object pushes the tibia back underneath the femur. In a high-velocity injury of this type, the shear force is enough to rupture the PCL holding the tibia in place.

A second mechanism of injury (more common with athletes) occurs when the foot is planted on the ground and the knee hyperextends. Hyperextension means the joint is as straight as it can be and then a force pushes it into even more extension or overextension, thus the term hyperextension.

When the patient gives either one of these histories, the physician directs his or her examination to test the PCL. Several tests are commonly used such as the posterior drawer test, posterior sag, and the reverse pivot shift. The examiner will also check knee motion, quadriceps muscle function, and compare external rotation of the legs (the Dial test).

Besides looking at the integrity of the posterior cruciate ligament, it’s important to evaluate if there’s been any damage to the blood vessels or nerves in the knee. Sensation, pulses, reflexes, and muscle strength will all be carefully reviewed.

Next, X-rays may be ordered. Any fractures or avulsion injuries can be seen on X-ray. An avulsion describes damage strong enough to pull a piece of bone away from the femur or tibia. The flat upper part of the tibia called the tibial plateau could also be fractured or damaged. Tibial plateau fractures are also visible on X-rays. Sometimes it can be difficult to tell if the PCL is partially or fully ruptured. Additional X-rays called stress radiographs and/or MRIs may be ordered for further clarification of the extent of damage.

Once the diagnosis has been made, then a plan of care must be determined. The severity of the injury usually guides who has surgery and how soon. For example, patients with avulsion injuries usually have surgery right away. The loose fragment of bone is screwed or stitched back in place with sutures.

Many players are actually able to participate in their sport with PCL-deficient knees. And they do so until the end of the season before considering surgery to reconstruct the knee and restore full stability. This is more likely to work when there is a partial tear, rather than a complete rupture. Undamaged supporting structures make it possible to continue functioning without a completely intact PCL. But when severe damage has been done to the ligament and its support system, then surgery (even mid-season surgery) is often advised.

The miserable malalignment syndrome refers to a group of anatomical changes in the lower extremity (leg) that can lead to knee pain and instability. The most common alterations include internal rotation of the femur (thigh bone). The rotation occurs at the distal (bottom) end where the femur helps form the knee joint.

The second feature is an inward facing patella (knee cap) referred to as winking patella. The lower leg formed by the tibia and a smaller bone (the fibula) rotate outwardly under the femur. And below that, the feet (supporting the entire structure of the body) are flat.

Changes in alignment like these anywhere along the kinetic chain can affect the position, movement, and function of the leg, especially the patellofemoral joint. The kinetic chain is the connection and force spread from foot to ankle to knee to thigh to hip. The patellofemoral joint is formed by the patella as it glides up and down over the front of the knee.

For example, a flatfoot position shifts the hindfoot away from the midline toward the other foot. This is called hindfoot varus. Further up the kinetic chain, that slight change at the foot and ankle then cause an increase in the Q-angle of the knee. The Q-angle is a normal angle where the femur and the tibia (shinbone) come together at the knee joint.

The patella normally sits at the center of this angle within the femoral groove. When the quadriceps muscle contracts, the angle in the knee straightens, pushing the patella to the outside of the knee. In cases where this angle is increased, the patella tends to shift outward with greater pressure. As the patella slides through the groove, it shifts to the outside. This places more pressure on one side than the other, leading to damage to the underlying articular cartilage.

The miserable malalignment syndrome puts a person at increased risk for dislocation of the patella — and not just once, but multiple times. The result can be a chronically unstable patellofemoral joint with ongoing pain and eventual arthritic changes.

It sounds like you may have experienced a patellofemoral joint dislocation. The patellofemoral joint is formed by the patella (kneecap) as it glides up and down over the front of the knee. Since the injury occurred suddenly and without previous injury, we refer to this as an acute episode. Symptoms of swelling, bleeding under the patella or bruising around the patella, and tenderness along the edge are signs that a dislocation occurred.

Treatment for acute patellofemoral joint trauma is usually with a period of immobilization in a cast or brace followed by a rehab program. A physical therapist will help you regain smooth, normal motion, proprioception, and strength. Proprioception refers to the joint’s sense of position, an important function when maintaining joint stability. This is important in preventing a second or even repeated episodes of this event.

Surgery is needed when there is severe damage such as bone fracture, muscle rupture, or detachment of the ligaments. A visit to the orthopedic surgeon would help rule out something of a more serious nature requiring surgery.

There was a reason for this episode of instability, even if it is not entirely clear to you what that might be. The surgeon will be able to evaluate your knee and possibly identify ways to prevent future episodes. That’s important because every time the kneecap dislocates, damage is done to the ligaments, soft tissues, and joint cartilage that can eventually lead to degenerative changes and possibly painful arthritis later on.

Treatment for this problem has not been very successful in the past. But new understanding of the biomechanics (anatomy and function) of the joint have opened up new management techniques. The first step is to see a physical therapist. The therapist will design a therapy program to restore full, balanced strength and function of the hip and knee muscles.

Activity modification will be required. Avoiding stairs, squatting, jumping, and biking can reduce the load on the patellofemoral joint. Weight loss is always advised for anyone who is overweight. Reducing the stress, pressure, and load on the joint can be very helpful. Medications such as pain relievers and antiinflammatories may be prescribed. Occasionally, the use of steroid or hyaluronic injections is beneficial.

Some patients find relief from pain using a patellar unloading sleeve (a slip on neoprene support). Bracing or taping may also be helpful but studies are lacking in providing evidence that these measures really make a difference. Often, a combination of these nonsurgical treatment approaches works the best.

But, if after three to six months, there’s been no improvement, then some patients may be candidates for surgery. What can the surgeon do? Well, there are a variety of techniques that can be used. Which one is best differs for each patient and depends on the underlying cause of the condition.

In some cases, it’s just a matter of removing any bone spurs and smoothing the edges of the patella. Other patients benefit from the release of the lateral retinaculum. This is a fibrous band of connective tissue along the outside edge of the patella. When it gets bound down or tethered, it can create uneven pull and a restraint to the natural up and down movement of the patella.

If there are holes in the articular cartilage called defects, it may be possible to repair the damage. A newer technique called autologous chondrocyte implantation (ACI) has had favorable results. Normal, healthy cartilage is removed from a nonweight-bearing portion of the knee joint. The cells are taken to a lab where they are used to grow more cells. The cells are then transplanted back into the patient to fill up the hole.

Cartilage implantation has worked well for smoothing out the surface of the knee joint. It may not be as successful along the back of the patella. There are two main reasons for failure of this technique. The first is abnormal tracking of the patella. If the patella is not riding up and down in the center of the femoral groove, the same problem will develop again. Anything contributing to the malalignment of the patella must be addressed along with chondrocyte implantation.

Secondly, resurfacing the patella may be successful but the patellofemoral joint takes quite a beating everyday. There is a lot of pressure and load on the surface of the patella. The mechanics of gliding up and down over the femur put a much greater demand on patellar articular cartilage than even on the knee joint itself. The implantation may not be able to hold up under such rigorous conditions.

Other procedures that may help alleviate pressure from the patellofemoral include tibial tubercle transfer, patellectomy (remove the patella), and patellofemoral arthroplasty (replace the patella).

Tibial tubercle transfer refers to the removal and relocation of the bump of bone called the tibial tubercle. This is the insertion point for the quadriceps muscle. The idea in transferring this area of bone is to change the pull of the quadriceps muscle on the patella and thereby reduce the load on the arthritic patella. The surgeon must plan this procedure carefully, using the results of X-rays, MRIs, and arthroscopy to determine what type of incision to use, where to make the incision, and how far to move the tubercle.

Treatment of patellofemoral problems is difficult. Disabling knee pain and patellofemoral breakdown may not respond to any of these limited surgical interventions. Sometimes it’s necessary to remove the patella completely. This is considered a more radical approach but it’s a simple and safe procedure that works. The down side is that the patient is left with a big loss in knee extension strength.

One alternative to just a patellectomy alone is a patellar replacement. A screw-on patellar shell is used to replace the patella once it is removed. Early efforts at patellofemoral replacement resulted in as many failures as successes. Newer designs and 3-D technology for designing the implant to fit the patient have improved overall results.

If all efforts fail to improve symptoms, motion, and function, then a total knee replacement (TKR) may be the final choice. This procedure is not advised for younger patients but reserved for older adults. Because of the abnormal alignment and mechanics that led to the patellofemoral arthritis in the first place, surgeons must approach a total knee replacement carefully. Imbalances must be corrected during the procedure to ensure optimal results.

You’ll want to go over with your surgeon each of the options available to you. Your age, activity level, and the underlying cause(s) of your condition will factor into the decision about which approach is best for you.