The knee is the largest and most complicated joint in the body. Although it's well constructed, it endures continuous stress and is prone to injury due to considerable weight-bearing responsibilities. Chronic knee pain can sneak up on anyone. What begins as mild aching after exercise can progress to sharp pain during daily activities, such as climbing steps or standing from a prolonged sitting position. Left untreated, knee pain can become a debilitating condition.

Patellofemoral pain is one of the most common types of knee pain. The patella (kneecap) is a small, flat triangular bone in front of the knee that protects the knee joint. It's attached at the top by the thigh muscles and secured at the bottom by lower leg muscles. A kneecap that functions properly slides over a groove on top of the femur. If the patella gets off track, it can produce pain and eventually result in patellofemoral syndrome (PFS).

Although knee pain frequently affects runners, especially between the ages of 18 and 35, everyone is susceptible. People between the ages of 18 and 35 are especially at risk because this is an active age group that causes wear and tear on the joints.

With PFS, most patients present with pain in the front of the knee, but symptoms can also radiate to the top, bottom and sides. Discomfort begins slowly as a general aching, which progressively worsens and intensifies to hinder walking, stooping and bending of the knee. Climbing up and down stairs can be problematic due to increased friction on the knee joint. Athletes often experience "cracking" of the knee joint during bending or extending. Running exacerbates symptoms, and this activity may become too painful to continue. Others can experience swelling or increased tightness around the joint..

Assessing the Causes

Research shows that an imbalance in the quadriceps allows the patella to track incorrectly. If thigh muscles are weak, an overall imbalance can cause insufficient support of the patella, which allows it to move outside of its groove. For example, when walking up steps, the thigh muscles contract to stabilize the knee joint. However, weak muscles force the patella to work overtime and eventually this aberrant movement causes damage to the articular cartilage that's supposed to protect joints and bones. In particular, degeneration of cartilage at the articulation between the bottom of the patella and femur is linked to PFS.

When assessing patients with knee pain, you should also check for foot abnormalities. If the feet aren't properly supported, increased pressure or over-rotation can contribute to PFS. In some cases, proper fitting shoes or custom orthoses can help resolve the problem.

PFS may also be misdiagnosed as chondromalacia patellae, a chronic degenerative condition that causes the cartilage around the patella to deteriorate. Although the condition produces similar symptoms, each malady requires different rehab strategies. Consider taking X-rays to see if any knee bone irregularities are present. A decrease in height around the knee joint can help confirm chondromalicia patellae.

But unlike chondromalacia patellae, PFS isn't characterized by spontaneous joint degeneration. Instead, trauma to a joint incites a guarding effect of the muscles. Left uncorrected, the muscles weaken, the joint becomes unstable and symptoms ensue. Overuse activities, such as running and skiing, can be as damaging to the knees as acute trauma from a fall or accident.

Building a Strong Defense

To rehab patients with PFS, you must condition muscles to support the joint structure. A strengthening program must increase power and endurance of the quadriceps, take pressure off the kneecap and reduce or eliminate symptoms.

Muscle and joint flexibility are important for patients with PFS. However, stretching can be painful for those who lack adequate strength. Therefore, focus on strengthening the legs first and then stretch the quadriceps, hamstrings, gastrocnemius and iliotibial band. Remind patients that proper stretching takes time and the benefits don't happen overnight. The key is to balance tone (strength) and flexibility (stretching).

Proper pain management is essential to PFS rehab, and you can use ice to reduce swelling and alleviate pain. Apply ice to an area for no more than 20 minutes and wait an hour to reapply. Studies also support the use of a non-pharmaceutical anti-inflammatory, which can reduce swelling without contraindications, except blood thinners. You can also use braces or taping techniques to support the knee and help correct lateral tracking of the patella. Although surgery may be a viable option in some cases, it's best to discourage such drastic measures, due to risky complications from scar tissue.

The knee is an intricate piece of human equipment that depends on surrounding muscles and joints to operate correctly. If you incorporate strength building and stabilization into customized rehab programs, you stand the best chance of relieving pain and alleviating PFS. .

Source: "Advance Directors in Rehabilitation" September 2006 Vol. 15 No. 9 .