What to expect after a tibial tubercle osteotomy? A 10-year retrospective study of clinical and radiologic outcomes.

INTRODUCTION

Patellofemoral instability (PFI) is a multifactorial entity that combines osseous and soft tissue abnormalities. Tibial tubercle osteotomy (TTO) addresses biomechanical malalignment but faces 50 % recurrence rates with TT-TG >20 mm. Long-term outcomes show 62.5 % success at 10-15 years post-TTO, though 16-21 % require reoperations. Current evidence lacks long-term data, underscoring the need for individualized surgical planning. This study evaluates 10-year outcomes via MRI and clinical outcomes to identify predictors of suboptimal results.

METHODS

A retrospective observational study was designed. Demographic and clinical data, including age, gender, number of dislocations, and revision surgery, were collected. Radiologic measures were patellar height, tilt, displacement, maltracking, and trochlear dysplasia. They were assessed with computed tomography (CT) preoperatively and magnetic resonance imaging (MRI) postoperatively, with further identification of chondral lesions. Functional evaluation was based on the Kujala and Lysholm scores.

RESULTS

Data from 36 knees were included. Recurrent dislocation occurred in 14 % (5 cases), primarily in younger females (median age 16) with residual malalignment. Symptomatic hardware removal (50 %) was the most common complication. Significant improvements were observed in the TT-TG distance (23 IQR 15.05-25.3 V S 15 IQR 10-18 mm, p = 0.002), patellar tilt and displacement with 0° of extension (patellar tilt: 28.5 IQR 17.75-34.25 V S 16.5 IQR 10-24.25°, p < 0.005; patellar displacement: 6.3 IQR 3.07-14.6 V S 2.5 IQR 0-8.25 mm, p = 0.01) and with active contraction only patellar tilt (34 IQR 24-42.5 V S 29 IQR 15-36° p = 0.014). Despite 54.8 % present with advanced chondropathy (Outerbridge III/IV), no correlation was found with age, alignment, or functional scores. The median Kujala score was 89.5 IQR 82.5-97.5, and the median Lysholm was 91 IQR 81.75-95.75.

CONCLUSION

TTO provides reliable long-term outcomes for patellofemoral instability. The risk of joint degeneration is non-negligible, especially in the setting of malalignment or older age on admission.

LEVEL OF EVIDENCE

III.