Patellar instability.

[trochlear dysplasia]

Patella instability can cause significant pain and functional limitations . Several factors can predispose to patella instability , such as ligamentous laxity , increased anterior TT-TG distance , patella alta , and trochlear dysplasia . Acquired factors include MPFL injury or abnormal quadriceps function . In many cases , first -time dislocation can successfully be managed with physical therapy and other nonoperative management ; however , more than one dislocation significantly increases the chance of recurrence . Surgical management can improve stability , but should be tailored to the injuries and anatomic risk factors for recurrent dislocation . Isolated lateral release is not supported by current literature and increases the risk of iatrogenic medial instability . Medial repair is usually reserved for patients with largely normal anatomy . MPFL reconstruction can successfully stabilize patients with medial soft tissue injury but is a technically demanding procedure with a high complication rate and risks of pain and arthrosis . Tibial tubercle osteotomy can address bony malalignment and also unload certain articular cartilage lesions while improving stability . Trochleoplasty may be indicated in individuals with a severely dysplastic trochlea that can not otherwise be stabilized . A combination of procedures may be necessary to fully address the multiple factors involved in causing pain , loss of function , and risk of recurrence in patients with patellar instability .