Predictors of Increased Complication Rate Following Tibial Tubercle Osteotomy (TTO)

Abstract

Purpose: The purpose of the current study was to define the incidence of minor and major complications following TTO at a tertiary-care institution, with determination of predictive factors related to the occurrence of a major complication.

Study design: Retrospective case series.

Methods: Patients who underwent TTO from 2011 to 2023 were retrospectively identified. Patients who did not have at least 30 days of follow-up and revision cases were excluded. Complications classified as "major" included intraoperative fracture, postoperative fracture, loss of fixation, delayed union, non-union, pulmonary embolism (PE), patella tendon rupture, deep infection, painful hardware requiring removal, arthrofibrosis requiring reoperation, recurrent patellar instability, reoperation for other indications, readmission, and revision. Complications classified as minor included superficial infection, deep venous thrombosis, wound dehiscence, and postoperative neuropraxia. Chi-square tests were used for categorical variables, t-tests for continuous variables.

Results: Four hundred and seventy-six TTOs in 436 patients were included in the final cohort with a mean follow-up of 1.9 years (range 1 month-10 years). Patients were 68.5% female with average age 28.3 years (range 13-57 years). The overall complication rate was 27.5 percent. Major complications were recorded in 23.7% of TTOs, and minor complications in 8.4% of TTOs. Reoperation was required in 16.6% of TTOs at a mean of 14 months following the index procedure. The most common complications were painful hardware requiring removal (6.5%), superficial infection (5.7%), and arthrofibrosis requiring return to the operating room (OR) (5.0%). Prior ipsilateral surgery was identified as a significant independent predictor of major complication by regression analysis. Hardware removal was more common with headed screws. Arthrofibrosis requiring reoperation was more common in patients who underwent a concomitant cartilage restoration/repair procedure.

Conclusion: The overall complication rate following tibial tubercle osteotomy was 27.5%, with painful hardware requiring removal (6.5%) as the most common complication, and an overall reoperation rate of 16.6%. TTOs with major complications were performed at earlier years, in patients who were older, had a previous ipsilateral arthroscopic knee surgery, had an indication of cartilage lesion/arthritis, and had a steeper osteotomy cut angle. Hardware removal was found to be more common in patients with headed as compared to headless screws. Complications also varied based on timing after surgery.

Keywords: Complication; Osteotomy; Patellofemoral cartilage.