Summary

Surgical stabilization including MFPL reconstruction for recurrent lateral patellar instability is an effective procedure for returning athletes to competitive sports with good clinical outcomes and low rates of recurrence at 4 year follow-up, however, strength deficits persist at 6 months after surgery, especially in those undergoing concomitant TTO, which may delay return to sport.

Abstract

Objectives: Medial patellofemoral ligament (MPFL) reconstruction and tibial tubercle osteotomy are commonly used to treat recurrent lateral patellar instability, yet there is limited available data on return to sport (RTS) following these procedures. The purpose of this study is to evaluate patient factors associated with excellent functional outcomes, including successful RTS, following surgical stabilization including MPFL reconstruction in competitive athletes with recurrent lateral patellar instability.

Methods

Athletes undergoing primary MPFL reconstruction for recurrent lateral instability from 2005-2013 were identified. Concomitant procedures, such as tibial tubercle osteotomy (TTO), were included. Patient demographic information, including BMI, gender, age, and pre-injury Tegner score were recorded. In addition, radiographs were reviewed for pre-operative patellar height (Caton Deschamps index) and trochlear dysplasia (Dejour classification). Isokinetic strength and functional testing were performed at 6 months post-operatively. Final Tegner scores, RTS status, subjective instability ratings, and Kujala scores were collected at a minimum of 2 years. Chi-square analysis for categorical variables and Wilcoxon rank-sums analysis for continuous variables were used to determine the relationship between the previously mentioned patient and knee characteristics with isokinetic data, RTS status, or Kujala scores.

Results

Thirty-nine athletes (23 male, 16 female) at a mean age of 17.5±2.9 years (range, 13-26) underwent primary MPFL reconstruction (32 autograft, 7 allograft) for recurrent patellar instability with a mean follow-up of 47±16 months. Sixteen patients (41%) underwent concomitant tibial tubercle osteotomies. Isokinetic data collected at 6 months post-operatively demonstrated mean knee flexion and extension strength deficits of 15±10% and 21±13%, respectively, compared to the contralateral leg (p<0.001 for both). Patients who underwent concomitant tibial tubercle osteotomy (p=0.04), males (p=0.01), and those with patella alta (p=0.04) had weaker 6-month isokinetic testing. Thirty-three of the thirty-nine (85%) athletes were able to RTS at a mean of 8±4 months. Patients undergoing MPFL with concomitant TTO (p=0.02) returned to sport at a slower rate. One patient (3%) reported an episode of recurrent dislocation requiring revision surgery. Kujala and Tegner scores at final follow-up were 91±6 and 6 (range, 4-9) respectively.

Conclusion

Surgical stabilization including MFPL reconstruction for recurrent lateral patellar instability is an effective procedure for returning athletes to competitive sports with good clinical outcomes and low rates of recurrence at 4 year follow-up, however, strength deficits persist at 6 months after surgery, especially in those undergoing concomitant TTO, which may delay return to sport.

Level of Evidence: Level IV, Retrospective Case Series