Poster 232: Performing a Concomitant Tibial Tubercle Osteotomy During Primary Medial Patellofemoral Ligament Reconstruction Does Not Lead to Increased Post-Operative Complication Rates

Abstract

Objectives:Tibial tubercle osteotomy is utilized to unload cartilage defects and/or to correct malalignment in the setting of patellofemoral instability and/or chondrosis. Controversy remains regarding the indications for TTO as an adjunct to soft tissue stabilization for patella instability. Our purpose was to evaluate safety and efficacy of MPFLR with or without concomitant tibial tubercle osteotomy (TTO). Our hypothesis was that adding TTO to MPFLR would lead to lower revision instability surgical rates but higher rates of overall re-operation, complication, and cost.Methods:We queried the MarketScan database in order to identify patients who underwent primary MPFLR from 2007-2015. Patients were stratified into cohorts based on concomitant TTO performed on the same day as index MPFLR. To minimize the effect of potential confounding on the direct comparison of patients undergoing the two procedures, a propensity-score match (PSM) was utilized. A greedy nearest-neighbor algorithm was employed to match patient cohorts with a 7:1 MPFLR to MPFLR + TTO ratio. Reoperations, complications, and costs were followed for two years post-index procedure. Patients without laterality codes were excluded. Results were analyzed statistically.Results:This study identified 968 patients who underwent primary MPFLR. Patients were stratified into two groups: 1) MPFLR only or 2) MPFLR + TTO. After matching the cohorts, mean age, sex distribution, and rates of baseline diabetes, hyperlipidemia, hypertension, tobacco use, and obesity were similar. Patients in the two cohorts experienced similar rates of postoperative complications (MPFLR + TTO: 9.9%, MPFLR: 8.7%, p= 0.6694). Rates of dislocation (MPFLR + TTO: 5.8%, MPFLR: 4.3%, p = 0.4434), stiffness (MPFLR + TTO: 0.8%, MPFLR: 2.5%, p = 0.2538), infection (MPFLR + TTO: 0.8%, MPFLR: 0.6%, p = 0.7559), and wound complication (MPFLR + TTO: 0.8% vs MPFLR: 0.8%, p = 1.000) were similarly low. Performing a concomitant TTO decreased revision surgery for instability (revision MPFLR) rates (6.6% vs 11.1%, p = 0.1327); however, this difference was not statistically significant. Hardware removal (MPFLR + TTO: 9.9%, MPFLR: 1.9%, p < 0.0001) was higher in the MPFLR + TTO cohort. Patients who underwent a concomitant TTO were associated with higher payments through 2 years of index surgery when compared to MPFLR only patients ($25,740 vs $17,727, p < 0.0001).Conclusions:Concomitant TTO at the time of MPFLR does not lead to increased post-operative complications. The addition of TTO to MPFLR reduced revision surgical rates for instability from 11.1 to 6.6% but this difference was not statistically significant. Combination TTO/MPFLR led to higher payments through 2 years. Further research is needed to refine the indications for TTO as a adjunct procedure to MPFLR and its impact on long-term stability and failure rates.Table 1.Demographics and Baseline ComorbiditiesTable 2.Postoperative Complications - within 90 daysTable 3.Quality OutcomesTable 4.Non-obese vs Obese Subgroup AnalysisTable 6.Age <30 vs Age >30 Subgroup AnalysisTable 7.Non-smoker versus Smoker Subgroup Analysis