Arthritis of the patellofemoral joint refers to degeneration (wearing out) of the cartilage on the underside of the patella (kneecap) and the trochlea (groove) of the femur (thigh bone). This condition can cause anterior knee pain and limitations in stair climbing and getting up from a chair. The patella (kneecap) is a bone on the front of the knee within the tendon of the quadriceps muscle. It rides in a groove (trochlea) of the femur. The protective layer of cartilage on the surface of the patella and trochlea allows the smooth, painless movement of the patella along the groove. Injury upon degeneration of the cartilage leads to arthritis, resulting in symptoms of pain, stiffness, and swelling of the knee.
Frequent Signs and Symptoms
- Knee pain, usually in the front of the knee or behind the kneecap
- Pain that worsens with sitting for long periods, arising from a sitting position, going up or down stairs or hills, kneeling, squatting, or wearing shoes with heels
- Pain with jumping
- Usually, achy pain but may be sharp
- Giving way, catching of the knee
- Often associated with swelling after activity
Etiology (Causes)
This condition commonly occurs in the aging population, although it may occur in younger patients following trauma such as a dislocation of the patella or patella fracture. Mechanical abnormalities or poor patella.