Chondromalacia Patella (Patellofemoral Syndrome)
Chondromalacia patella facts
•Chondromalacia patella is the most common cause of chronic knee pain.
•Chondromalacia patella has also been called patellofemoral syndrome.
•The pain of chondromalacia patella is aggravated by activity or prolonged sitting with bent knees.
•Abnormal "tracking" allows the kneecap (patella) to grate over the lower end of the thighbone (femur), causing chronic inflammation and pain.
•Treatment involves improving the alignment of the patella during contraction of the thigh muscle.
What is the chondromalacia patella?
Chondromalacia patella is abnormal softening of the cartilage of the underside the kneecap (patella). It is a cause of pain in the front of the knee (anterior knee pain). Chondromalacia patella is one of the most common causes of chronic knee pain. Chondromalacia patella results from degeneration of cartilage due to poor alignment of the kneecap (patella) as it slides over the lower end of the thighbone (femur). This process is sometimes referred to as patellofemoral syndrome.
What causes chondromalacia patella?
The patella (kneecap) is normally pulled over the end of the femur in a straight line by the quadriceps (thigh) muscle. Patients with chondromalacia patella frequently have abnormal patellar "tracking" toward the lateral (outer) side of the femur. This slightly off-kilter pathway allows the undersurface of the patella to grate along the femur, causing chronic inflammation and pain. Certain individuals are predisposed to develop chondromalacia patella: females, knock-kneed or flat-footed runners, or those with an unusually shaped patella undersurface.
What are the symptoms and signs of chondromalacia patella?
The symptoms of chondromalacia patella are generally a vague discomfort of the inner front of the knee, aggravated by activity (running, jumping, climbing or descending stairs) or by prolonged sitting with knees in a moderately bent position (the so called "theater sign" of pain upon arising from a desk or theater seat). Some patients may also have a vague sense of "tightness" or "fullness" in the knee area. Occasionally, if chronic symptoms are ignored, the associated loss of quadriceps (thigh) muscle strength may cause the leg to "give out." Besides an obvious reduction in quadriceps muscle mass, mild swelling of the knee area may occur.
How is chondromalacia patella diagnosed?
Chondromalacia patella is suspected in a person with anterior knee pain, especially in teenage females or young adults. With manual compression of the kneecap while the quadriceps muscle is tightened, there can be pain. This is referred to as the positive "shrug" sign. Generally, there is no associated swelling (knee joint effusion).
X-rays or MRIs may be done to confirm the inflammation on the posterior part of the patella.