The patella, or kneecap, rests on the groove between the femur and the tibia. Subluxation is a partial dislocation, which occurs when the patella slides partially off track.
Women’s thighbones, or femurs, angle toward the center of the body to compensate for the hip-widening effects of puberty. Consequently, 30 to 40 percent of women have abnormal knee alignment. Men also suffer abnormal knee alignment, but at a lower rate than women. Injury, particularly a twisting or contact injury also causes subluxation.
Contact sports, or sports involving quick motion, twisting, or pivoting can lead to knee subluxation. The first time the knee subluxates, it causes the tissue holding the knee in place to tear or stretch. When the tissue heals in the stretched position, the kneecap tends to subluxate repeatedly. Each time the knee subluxates, it can cause damage to the cartilage and joint. Knee subluxation can contribute to degenerative knee damage and arthritis.