What is Chondromalacia of the Patella?
Chondromalacia of the patella is a major component of patellofemoral pain, or pain in the anterior knee. The patella sits in a groove on the femur (trochlear groove). The undersurface of the patella and the surface of the trochlear groove is lined with a layer of articular cartilage. Normally, this articular cartilage is quite thick, with a smooth surface and quite dense.
What Causes Chondromalacia?
Chondromalacia is the softening of the articular cartilage that eventually leads to the breakdown of the cartilage. The breakdown can begin as small fissures are created in the surface. Over time with continued stress on the cartilage, the fissures become wider and deepen. At first, swelling in the knee may be minimal, but with further damage, the swelling will increase.
The patella acts as an anatomical pulley for the quadriceps extensor mechanism. As a result, the patella is subjected to large compression loads as it performs its job. If the patella is tracking in the middle of the trochlear groove, then the compression loads are distributed over a larger surface area. The problem arises when the patella tracks more on one side (usually the lateral side) of the trochlear groove. In this alignment, the compression loads are distributed over a smaller surface area. The breakdown is usually considered to be the result of an overuse injury. However, a hard, direct blow to the patella (landing on your patella) could create a traumatic injury to the articular cartilage.
Why is My Kneecap Misaligned?
A combination of factors can lead to the malalignment of the patella. Weakness in the quadriceps may allow the patella to track improperly. Also, weakness in the core and hip abductor/external rotator muscles will not maintain the proper hip/knee/foot alignment (the knee falls into valgus) while running and as a result the patella will track laterally. Tightness in the iliotibial band (ITB) can pull the patella laterally. A tight Achilles tendon can cause excessive pronation and eversion in the foot which also makes the patella track to the lateral side.
What is the Treatment for Chondromalacia?
Strengthen the quadriceps, hip, and core muscles (along with hamstrings and calf muscles). Increase flexibility of knee, hip, and calf muscles. Modify training to allow pain-free training. This may mean reducing running volume (mileage and days per week) and limit downhill running. Modify your running mechanics. Rather than landing with the knee extended and with a heel strike first, land on the mid-foot with a shorter stride (foot lands more underneath you) and slightly increase the cadence.
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