Habitual patellar dislocation 40 years after failed conservative treatment: A case report

Patellar dislocation is often caused by congenital bone morphological abnormalities or joint laxity and is rarely traumatic. We report a case of long-term habitual patellar dislocation due to trauma 40 years ago without abnormal bone morphology, which required a combined procedure, including the Elmslie–Trillat (ET) procedure, massive lateral release, and medial patellofemoral ligament (MPFL) reconstruction, resulting in favorable outcomes. A 52-year-old male, with no specific underlying disease, dislocated his right patella due to falls when he was 13 years old and underwent conservative treatment. Subsequently, patellofemoral instability remained, and the patella began dislocating outward every time he flexed his knee joint; however, he could walk without pain. Therefore, he left it untreated for more than 40 years. His Lysholm and Kujala scores were 77 and 73 points, respectively. Radiographs showed no abnormal bone morphology with a tibial tuberosity–tibial groove (TT–TG) distance of 12 mm and a tibial external rotation angle of 5°. We released the distal iliotibial ligament and lateral bursa following the Fulkerson procedure, and the patella was stabilized from 0° to 60° of knee flexion. The ET procedure was subsequently performed. The patella was moved 13 mm medially and fixed using tibial coarse translation, which stabilized the patella up to 90°. However, when flexed beyond 90°, the patella was displaced laterally; therefore, MPFL reconstruction with autologous hamstring tendon was performed. Range of motion exercises were initiated 1 day postoperatively. Partial and full weight-bearing were allowed 2 and 4 weeks postoperatively, respectively. At the final outpatient follow-up at 8 months postoperatively, the patient could walk without patellofemoral instability; the Lysholm and Kujala scores had recovered from 77 to 97 and from 73 to 93 points, respectively. This combined patellofemoral-stabilizing procedure is considered the treatment of choice for patients with habitual patellar dislocation despite the chronicity.