Comparative Postoperative Changes Over Time in Patellar Height After Medial Patellofemoral Ligament Reconstruction With and Without Tibial Tubercle Osteotomy

Background: The postoperative influence of medial patellofemoral ligament reconstruction (MPFLR)—performed alone or in conjunction with tibial tubercle osteotomy (MPFLR+TTO)—on patellar height is not well-understood. Purpose/Hypothesis: The purpose was to compare longitudinal changes in patellar height after MPFLR and MPFLR+TTO. It was hypothesized that knees undergoing MPFLR will experience a decrease in patellar height that is greater than that of knees undergoing MPFLR +TTO and that both cohorts will return to Caton-Deschamps index (CDI) measures near that of preoperative levels. Study Design: Cohort study; Level of evidence, 3. Methods: This is a retrospective radiographic review of skeletally mature patients >15 years of age who underwent either an MPFLR or an MPFLR+TTO with lateral knee radiographs available from the preoperative period, 0 to 6 months (early) postoperatively, and >6 months (final) postoperatively. Exclusion criteria were (1) distalization TTO and (2) previous procedures, or procedures postoperatively near the extensor mechanism. CDI was used to quantify patellar height. Paired Student t tests and a repeated-measures analysis of variance was performed to evaluate the effect of CDI changes between MPFLR and MPFLR+TTO. Results: A total of 62 knees in 61 patients (55% female [34/62 knees]) were included, with n = 27 knees undergoing MPFLR and n = 35 knees with MPFLR+TTO. Mean age was 25.9 ± 9.8 years (range, 15-58 years). Mean time from surgery to early postoperative imaging was 1.9 ± 1.4 months with MPFLR and 2.4 ± 0.8 months with MPFLR+TTO ( P = .08). Mean time from surgery to final follow-up imaging was 26.3 ± 24.6 months with MPFLR and 23.4 ± 17.8 months with MPFLR+TTO ( P = .59). Preoperative mean CDI values were comparable between the MPFLR and MPFLR+TTO (1.15 ± 0.20 vs 1.18 ± 0.13; P = .13). At early follow-up (0-6 months postoperatively), mean CDI values with MPFLR decreased to 1.01 ± 0.18, compared with MPFLR+TTO at 1.11 ± 0.15 ( P = .003). At final follow-up (>1 year postoperatively), the CDI values were similar between MPFLR (1.13 ± 0.21) and MPFLR+TTO (1.13 ± 0.14) ( P = .79). Conclusion: Our study showed that MPFLR both with and without TTO demonstrated an eventual return toward preoperative patellar height, yet they followed different early postoperative trajectories. MPFLR demonstrated an early decrease in patellar height that progressively relengthened over time, whereas MPFLR+TTO exhibited almost no changes in patellar height.