Do I Need Knee Surgery?

author : AMSSM

comments : 0

I have several years of pain behind both kneecaps that I had diagnosed as chondromalacia, or patella femoral syndrome. Rest has helped, but I'm wondering if surgery offers a more full recovery.

Member Question

I have several years of pain behind both kneecaps that I had diagnosed earlier this year as chondromalacia, or patella femoral syndrome. The doctor took xrays and says I had moderate alignment issues and he recommended isometrics. Restrictions on cycling of 10 to 20 minutes max spinning, no mashing big rings. Is there any success with exercises?

It seems any real power I put through the knee causes the pain. Rest has helped, but I'm wondering if a more full recovery could be possible with surgery. Not that I'm excited about the idea, but this cycle of an instant of sharp pain followed by baby steps for a month, going down stairs on the butt, then three months later being back to 60% strength and ready for the next sharp pain to start the cycle over again is getting very old. A run of a few hundred yards will cause a dull tell-tale ache. Then something always finishes it off, kneeling lifting etc.

From most online info I have found, runners knee is usually little more than a temporary bother. I'm a 6'1 beanpole so losing weight shouldn't be an issue with the knee.

Answer by Sean Robinson, MD 
Member AMSSM 

I am sorry to hear about your frustrating knee pain. You are not alone, it sounds that your symptoms are consistent with what we call anterior knee pain. This happens to be one of the most common ailments seen in sports medicine centers. Anterior knee pain is a symptom and has a variety of causes. The most common cause is patellofemoral pain syndrome. It is important to note that chondromalacia patella is a subset of patellofemoral pain syndrome and is usually an arthroscopic, not a clinical diagnosis. Chondromalacia patella may be evident on advanced imaging such as MRI or CT scan; again, most feel that it is a different etiology than patellofemoral pain syndrome.

Causes of Patellofemoral Pain

Despite years of research and investigating the exact cause of patellofemoral pain syndrome we still do not have a complete understanding of this syndrome. It has been associated with a number of different factors such as; damaged articular cartilage (as is the case for chondromalacia), alignment factors (notably leg length discrepancy), muscle imbalance, and activity levels. Research has shown the following risk factors can cause patellofemoral pain syndrome; trauma, overuse, muscle dysfunction, tight lateral restraints (soft tissues) of the knee, patellar hypermobility and poor quadriceps flexibility. However more research needs to be done to fully understand this syndrome.

Patellar Function

The patella or kneecap is a “floating” bone that is associated with your knee joint. It is a flat, triangular bone, situated on the front of the knee joint. It makes up the patellofemoral joint along with the femur (thigh bone). Its primary functional role is during knee extension. It increases the leverage of the quadriceps muscle by making it act at a greater angle, thus increasing the torque/strength of the joint. The presence of the patella in the extensor apparatus of the knee protects the tendon from friction and permits the extensor apparatus to tolerate high compressive loads. It is approximated that the forces on the patella range during different activities. While walking, the forces can be 0.5-1 times your body weight, when climbing stairs this force will increase to 3 times your body weight and with squatting up to 7-8 times your body weight. The patella also serves to protect the front of the joint and provide stability. The stability of this joint is important and is felt that instability can cause the patella to track incorrectly within the joint. Patellar stability and tracking depend on the correct interaction between the joint geometry, muscle actions (quadriceps), and passive restraints (soft tissues, ligaments and tendons). Furthermore, the patella plays a role in the aesthetic appearance of the knee.

An important aspect of the patellofemoral joint and the patella is the underside of the bone. It is composed of cartilage and this is called the articular side (this is the side that the patella makes contact with, and slides over the femur). Cartilage is a rigid yet flexible connective tissue found in many areas of the body. There are three classifications of cartilage, one of which is found in patellofemoral joint: hyaline cartilage. Articular cartilage is named because it coats areas of bone that are in close proximity to each other. It is found at the ends of your femur (thigh bone), tibia (leg bone) and on the underside of your patella (kneecap). Articular cartilage is important for the patella because it provides a smooth surface for your bones to guide and it acts as a shock absorber. However, it does not have its own blood supply thus relies on the fluid in your joint (called synovial fluid) for its health. Because of this, it has little ability to heal itself if damaged. Thus, it is important to realize that cartilage will not “grow back” if damaged or surgically removed.

Treatment for Anterior Knee Pain

The prevailing thought for treatment of anterior knee pain is to start with conservative treatment and to use surgery as a last resort. Initial treatment is typically relative rest to reduce the pain. Reduction in activity along with identifying precipitating pain factors will aid in initial pain reduction. The idea is to establish a pain-free base, so early strengthening is successful with avoidance of reflex inhibition issues, this is the body’s natural response to alter function or alignment because of underlying pain.

For long-term treatment the most common form of treatment is a comprehensive physical therapy program. It is important to realize that a successful rehabilitation process is going to take months of education and hard work to get back to cycling, running and swimming. It is also important to remember that solving your current issue is important, however we also do not want re-injury to occur thus sticking to the treatment plan after pain resolves is important. It is quoted in the literature that success in the short-term occurs in at least 80% of individuals and in the long-term, 60%.

The therapeutic plan should includes attention to movement patterns, biofeedback via tapping, muscle strengthening focusing on individual muscles but also the ratio of power between muscle groups. Education should play an important part of your rehabilitation process. Alignment factors may require consideration of footwear advice or use of orthotics. If patellar instability is an issue one may consider a patellar stabilizing brace.

Surgery

Surgical intervention, again, is considered the last resort for treatment of patellofemoral syndrome. It could be considered when conservative treatment, as discussed above, fails. Surgical treatment would be recommended after identification of a specific abnormality of alignment and to evaluate the degree of articular cartilage damage. Though it is interesting to note that studies looking at the articular surface of the patella, pathological findings have not been predictive of surgical outcomes. It is best left to a surgeon that is knowledgeable about the different causes of anterior knee pain, and has known experience with the limitations of surgery for this syndrome.

Being mindful of what is exacerbating your pain and changing these patterns will prevent future pain flares or progression of your knee pain. Being adherent to a well-structured comprehensive physical therapy and continuing home exercises is the most important part of your success.

Sincerely,
Sean Robinson, MD
Oregon Health and Science University

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date: September 19, 2012