Incidence of Complications, Recurrent Instability, and All-Cause Reoperations After Tibial Tubercle Osteotomy for Patellofemoral Instability: A Systematic Review and Meta-analysis of the Literature.

Background: Patellofemoral instability (PFI) is a condition that leads to recurrent dislocation events and is typically secondary to extensor mechanism malalignment and rotational deformities. To correct malalignment, a tibial tubercle osteotomy (TTO) can be performed; however, an understanding of the associated complications, recurrence rates, and potential for reoperation is necessary. Purpose: To systematically review the literature to determine the incidence of postoperative complications, rate of recurrent instability, and all-cause reoperation rate after TTO for PFI. Study Design: Systematic review; Level of evidence 4. Methods: The Cochrane Database of Systematic Reviews, PubMed, Embase, MEDLINE, and CINAHL were queried for studies that reported complications after TTO. No date limits were applied. A total of 1050 studies were identified. Complications were categorized into "minor" and "major" groups using a modified Clavien-Dindo Classification. A meta-analysis was conducted to examine complication rates, recurrent instability, and all-cause reoperation, utilizing a DerSimonian and Laird random-effects model. A meta-analysis for recurrent instability was subgrouped according to follow-up periods of ≤2 years and >2 years. Results: A total of 38 studies were included, comprising 1546 patients, representing 1733 knees. The study dates ranged from 1989 to 2024, and the level of evidence ranged from 2 to 4. The weighted mean age at surgery was 24.1 years (range, 20-54 years), and 67% of patients were women. The weighted mean follow-up of all studies was 4.2 years. Overall, 197 minor complications, 39 major complications, 90 recurrent instability events, and 275 reoperations were identified. The minor complication rate was 9% (range, 0%-65% [95% CI, 6%-13%]). The major complication rate was 3% (range, 0%-10% [95% CI, 3%-4%]). Seven studies had a ≤2-year follow-up, and the remaining 31 studies had a >2-year follow-up. The recurrent instability rate was 3% in studies with ≤2 years of follow-ups (range, 0%-26% [95% CI, 1%-13%]). In studies with >2 years of follow-up, the recurrent instability rate was 8% (range, 0%-31% [95% CI, 6%-12%]). The all-cause reoperation rate was 16% (range, 0%-54% [95% CI, 11%-21%]). Conclusion: This systematic review and meta-analysis identified the incidence of complications (17%), the rate of recurrent instability (3%-8%), and the all-cause reoperation rate (16%) after TTO. TTO, performed alone or in combination with medial patellofemoral ligament reconstruction for the treatment of PFI, reliably improved clinical outcome scores in the setting of variable complication rates. Interestingly, rates of recurrent instability increased over time, and most reoperations were undertaken for hardware removal rather than revision patellar stabilization surgery.