Patellar instability occurs when the kneecap (patella) slips partially or fully out of its normal groove on the thigh bone, ranging from a single dislocation to a pattern of recurrent instability.
Often results from a twisting injury or direct blow, but underlying anatomic factors — a shallow groove, ligament laxity, or malalignment — make some patients more prone to instability, sometimes with little or no trauma.
A visible shift or dislocation of the kneecap, sudden pain, swelling, and a sense of the knee buckling or giving way, particularly with pivoting or going up and down stairs.
A first-time dislocation is often treated with bracing and physical therapy to strengthen the muscles that stabilize the kneecap. Recurrent instability, or a first dislocation with significant cartilage damage, is often treated with MPFL reconstruction — rebuilding the ligament that primarily holds the kneecap in place. In some cases, underlying bony anatomy (such as a shallow groove or malalignment of the shin bone) also contributes to instability, and a bony procedure — such as a tibial tubercle osteotomy — may be necessary alongside ligament reconstruction to meaningfully decrease the risk of the kneecap dislocating again.
Think you might have this condition? An accurate diagnosis starts with an exam — schedule a consultation with Dr. Thomson.
Schedule a ConsultThis page is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Every injury is different — always consult Dr. Thomson or another qualified physician for a personalized evaluation.