BACKGROUND : To describe a novel 'four-in-one' procedure - including tibial tubercle proximalization, extensive lateral release, tibial tubercle medialization, and medial patellofemoral ligament reconstruction - for treating severe habitual patellar dislocation (HPD) in adults, and to report its early clinical outcomes. METHODS : Thirteen patients (13 knees) with severe primary HPD received this procedure. Results of the physical examinations, including apprehension tests and patellar tracking throughout full range of motion, were recorded pre-operatively and at final follow-up. Radiological assessments included standard anteroposterior view, true lateral view at 30° knee flexion, axial views of the patellofemoral joint at both 30° and maximum angle of knee flexion, and computed tomography scans at full knee extension pre-operatively and at final follow-up. Subjective patellofemoral functions were evaluated with the Kujala functional score before the index procedure and at final follow-up visit. RESULTS : All 13 patients were followed for an average period of 35.5 months (range, 25-49). After the index 'four-in-one' procedure no patient reported reoccurrence of patellar dislocation at the final follow-up visit. Radiographically, there was a statistically significant improvement in the congruence angle from 75.2 ± 16.3° pre-operatively to -7.2 ± 5.4° postoperatively (P < 0.01) and in the lateral patellofemoral angle from -66.3 ± 8.3° pre-operatively to 6.3 ± 2.6° postoperatively (P < 0.01). The average pre-operative Kujala functional score was 41.4 and average postoperative score was 94.9 (P < 0.05). CONCLUSIONS : The novel 'four-in-one' procedure effectively treated HPD in adults with severe quadriceps contracture.
