Fig 2.

Intraoperative examination of patellar maltracking and instability of the left knee showing more than 2 quadrants of lateral patellar translation. The black dashed line indicates the patella, and the white arrows indicate lateral translation. The examination is performed with the patient under anesthesia and positioned supine on the operative table. Medial and lateral patellar translation should be assessed at varying angles of flexion prior to surgery to further evaluate the degree of patellar maltracking. Other examinations that should be performed with the patient under anesthesia include assessments of patellar tilt, passive internal and external rotation of the hip, and the degree of knee flexion at which patellar instability is most appreciated.