When the kneecap slides out of place this is known as a patellar dislocation. The kneecap has another name known as the patella. The patella fits securely in a V-shaped groove in front of the knee (trochlea) and when the leg is bent or straightened it moves up and down .
Multiple dislocations may be caused due to several important ligaments, blood vessels and nerves which are damaged. Repeated patella dislocations should be concerning as the health and integrity of the joint and leg may be at risk. Factors that may increase your chance of patellar dislocation include: Weak thigh muscles. A patella that sits too high on the thigh bone. Excess pronation of the feet — inward roll of the feet when walking or running. In adults, the delayed presentation of this condition is often due to symptoms caused by the onset of severe secondary osteoarthritis.
Degeneration of the patellar cartilage is often observed in patients with recurrent patellar dislocation (RPD). When cartilage wears away, it becomes frayed and, when the wear is severe, the underlying bone may become exposed. Patellofemoral arthritis occurs when the articular cartilage along the trochlear groove and on the underside of the patella wears down and becomes inflamed.
Surgery may occasionally be needed if the kneecap keeps dislocating. A common procedure is a medial patellofemoral ligament (MPFL) repair. This is where the connective tissue (ligament) that helps hold the kneecap in place is repaired and strengthened.