Extensor Mechanism Centralization Using Autograft Hamstring for Laterally Dislocating Patella

Patellofemoral complications following total knee arthroplasty (TKA) are some of the most commonly cited complications in the literature, accounting for up to 50% of secondary procedures in the literature. Lateral dislocation of the patella, while rare, is one of many causes of extensor mechanism dysfunction. We sought to evaluate a novel patellar centralization procedure by comparing patients’ pre- and postoperative clinical and radiographic data. A retrospective case-series study was performed on 12 patient knees (5 male and 7 female) presenting with ambulatory dysfunction due to laterally dislocating patella. All of the knees had component revision combined with hamstring autograft tendon weave and medial reefing of the retinaculum and vastus medialis. The results revealed reliable stabilization of the patella and improved extensor lag at a mean 2.2±2.2 years’ short-term follow-up, which correlated with improved postoperative radiographic measurements. Range of motion in both flexion and extension was improved postoperatively. Improvements in radiographic measures of patellar tilt and patellar displacement were statistically significant, with reductions in the mean patellar tilt from 41.5°±25.9° to 3.9°±13.7° (P=.004), and in the mean patellar displacement from 2.8±2.1 cm to 0.8±0.9 cm (P=.012). Our study findings support the use of the extensor mechanism centralization procedure with autograft hamstring in management of laterally dislocating patella after TKA.