Outcomes following Medializing Tibial Tubercle Osteotomy for Lateral Patellar Instability in Patients with Patella Alta.

INTRODUCTION

Lateral patellar instability is characterized by patellar subluxation or dislocation secondary to traumatic injury, ligamentous laxity, or other pathoanatomy of the knee. Management often requires surgical stabilization via a tibial-tubercle osteotomy. The purpose of this study is to determine if patella alta is a risk factor for poor postoperative outcomes and return to activity following a medializing tibial-tubercle osteotomy in a young, active-duty military population.

MATERIALS AND

METHODS

This is a retrospective review of 42 military patients who received a medializing tibial-tubercle osteotomy for recurrent lateral patellar with a minimum of 2-year follow-up. No other stabilization procedures (i.e., medial patellofemoral ligament reconstruction) were offered or performed during the study period. t-Test, Chi square, and univariate logistic regression were used to determine if patella alta was associated Single Assessment Numeric Evaluation (SANE) scores, postoperative pain, recurrent instability, need for revision surgery, or an adverse outcome resulting in military activity limitations or medical separation.

RESULTS

Of the 42 subjects, 30 were found to have patella alta as defined by Insall-Salvati index, Caton-Deschamps index, or patellar tendon length to patella length ratios. No significant relationship was identified between patella alta and post-operative SANE score (P = .752), post-operative pain (P = .673), recurrent dislocation (P = .248), revision surgery (P = .868) or adverse outcomes requiring permanent activity modifications or medical separation from the military (P = .071). Male sex was found to be protective of adverse outcomes (P = .042).

CONCLUSION

These data suggest that patella alta is not an independent risk factor for poor outcomes following a medializing tibial-tubercle osteotomy for the management of lateral patella instability in a military population. Female sex is a significant predictor of adverse outcomes. A larger study is warranted to confirm these findings and further investigate the significance of patella alta in patients receiving stabilization procedures for lateral patella instability.