Trochleoplasty Versus Nontrochleoplasty Procedures in Treating Patellar Instability Caused by Severe Trochlear Dysplasia

Purpose: The purpose of this study was to compare the clinical outcomes and postoperative complication rates between patients who underwent trochleoplasty or nontrochleoplasty procedures in treating patellar instability caused by severe trochlear dysplasia (STD). Methods: The PubMed database was searched using specific inclusion and exclusion criteria for clinical studies reporting indexed orthopaedic treatments of patellar instability caused by STD (Dejour type B to D). Participants within studies were classified into one of the 2 treatment groups: (1) the trochleoplasty group (group T) and (2) the nontrochleoplasty group (group N). Clinical outcomes and postoperative complications were analyzed. Results: Seventeen studies were finally included. There were in total 459 knees that underwent the indexed orthopaedic treatments of patellar instability caused by STD (Dejour type B to D). Eleven studies, including 329 knees, formed the trochleoplasty group (group T), and the remaining 6 studies, including 130 knees, composed the nontrochleoplasty group (group N). All the clinical outcomes within groups had improved significantly (P < .05) at the final follow-up. No studies directly compared the clinical outcomes between the 2 groups. The postoperative complication analysis showed superior results for the trochleoplasty group in (1) patellar redislocation rate and (2) percentage of patellofemoral osteoarthritis (Iwano grade 2 or greater) progression findings but an inferior outcome with respect to the range of motion (ROM) deficit compared with the nontrochleoplasty group. Conclusions: This systematic review showed significant postoperative improvements both in patients undergoing the trochleoplasty procedures and in patients undergoing the nontrochleoplasty procedures for the treatment of patellar instability caused by STD in all the included studies. However, there is limited evidence regarding the comparative advantages toward the optimal treatment. The postoperative complication rate has been considered to be the best measurement of operative success. To prevent the patella from redislocating and patellofemoral osteoarthritis from progressing, trochleoplasty procedures should be considered. Meanwhile, one should be cautious about the postoperative ROM deficit before choosing trochleoplasty procedures. Level of Evidence: Level IV, systematic review of Level III and IV studies.