Summary

In the first and largest cohort of revision tibial tubercle osteotomies (TTO) ever reported, we find that revision TTO can be performed safely with high rates of osseous union and low rates of recurrent instability.

Abstract

Background

While tibial tubercle osteotomy (TTO) is a highly effective treatment for patellofemoral malalignment, some patients may have recurrent symptoms after surgery. To date, there is little data on revision TTO (rTTO), and whether rTTO is either safe or efficacious is unknown. The purpose of this study was to evaluate the reasons for and complications following rTTO.

Methods

This was a retrospective review of a single high-volume patellofemoral surgeon for all patients undergoing rTTO from 2016 to 2023. Demographic characteristics, indications for primary and revision surgery, operative characteristics, concomitant procedures, range of motion, radiography, and complications were collected. Univariate analyses (i.e., Fisher’s exact or Student t-tests, as appropriate) were used to compare groups.

Results

There were 16 knees (14 patients) undergoing rTTO, including 10 (63%) for persistent malignment (all of whom had chondral damage requiring concomitant intervention) and 6 (38%) for fracture/non-union. The knees undergoing rTTO for malalignment were 90% female, compared to 33% female for fracture/non-union (p=0.04). Mean time to revision was 12.3 years (range: 8 months-21 years) for persistent malalignment patients compared to 1.8 years (1 month-9.4 years) for fracture/non-union patients (p=0.02; when excluding one patient who fractured 9.4 years postoperatively: mean 3 months [range 1-5 months], p<0.001). For persistent malalignment rTTOs, the average ROM at 12-weeks was 0-130°, all achieved union, and the only complication (10% [1/10]) was arthrofibrosis (0-65° at 6-weeks) requiring arthroscopic lysis of adhesions (0-140° at 12-weeks). At an average follow-up for 3.9 years, there were no cases of new or recurrent patellar instability following rTTO. Similarly, at an average follow-up of 2.7 years, all (6/6) knees undergoing rTTO for fracture/non-union achieved union, with delayed union requiring percutaneous bone marrow grafting at 4-months postop being the only complication in this cohort.

Conclusions

Patients undergoing rTTO demonstrated low complication rates and high union rates. There is a high incidence of chondral wear requiring concomitant intervention among patients undergoing rTTO for persistent malalignment. While this is a relatively rare procedure, the results of the current study on largest cohort of rTTO patients ever reported suggest this can be a safe and effective option for patients with recurrent symptoms or fracture/non-union after primary TTO.