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From the American Academy of Orthopaedic Surgeons
Patellar Instability
Patellar instability is defined as abnormal, clinically symptomatic, lateral or, in rare cases, medial translation of the patella out of the trochlear groove. Instability includes dislocations as well as subluxations, both of which can be either traumatic or atraumatic. One of the considerations in the management of patellar instability is whether the instability is due to an acute patellar dislocation or chronic/recurrent instability. The article reviews the pathophysiology and clinical presentation of patellar instability and reviews the management options for acute and for chronic/recurrent instability. Two surgical techniques are reviewed in detail: anteromedialization and MPFL reconstruction. Video is available.
Keywords: patellofemoral dysfunction, patellofemoral dislocation, patella subluxation, patellofemoral joint dysfunction, patellofemoral pain, patellofemoral pain syndrome, dislocated kneecap, etiology, classification, patellofemoral joint anatomy, patellofemoral joint biomechanics, trochlear dysplasia, diagnosis, patient history, physical examination, imaging, radiography, MRI, CT, management, nonsurgical treatment, surgical treatment, surgical techniques, proximal realignment, distal realignment, combined realignment, anteromedialization (AMZ) of tibial tubercle, medial patellofemoral ligament reconstruction, semitendinosus graft, indications, contraindications, complications, outcomes, rehabilitation