Summary

Evaluation of a functional return to sport assesment at six months after surgery for reccurrent patellar instability.

Abstract

Purpose

To evaluate the feasibility of functional test battery in assessing readiness for return to sport (RTS) six months after surgery for recurrent patellar dislocation with an “a la carte” approach.

Methods

A prospective cohort of 57 patients who underwent surgery for recurrent patellar instability were assessed at six months follow-up. The RTS test battery included Lower Quarter Y-Balance Test (YBT-LQ), single-legged hop tests and isokinetic strength tests. Banff Patellofemoral Instability Instrument (BPII) 2.0 and Norwich Patellar Instability score (NPI) were also utilized. RTS clearance criteria were defined as: =4 cm YBT-LQ anterior reach difference between limbs and Leg Symmetry Index (LSI) =95% in the YBT-LQ composite score. LSI =85% for all single-leg hop tasks and LSI =90% in quadriceps strength.

Results

All patients were able to complete the YBT-LQ and strength tests. Fifty-two (91%) completed all hop tests. For the YBT-LQ test, 69% achieved an anterior reach asymmetry =4cm, and 65% had a LSI =95% in composite score. Mean LSI of all four hop tests was 91% and 61% had an LSI =85%. For the isokinetic strength test, 22% passed criteria for LSI peak torque quadriceps strength at 60o/s. Nine (16%) patients were deemed ready to RTS, passing all criteria. Mean BPII 2.0 and NPI score was 67.4 (19.6) and 9.9 (10.8) respectively. A long duration from first dislocation to operation and age >20 years was associated with a worse performance on the hop tests. The extent of surgery did not affect neither performance on functional tests nor the PROM scores.

Conclusion

Although only a minority of patients were deemed ready (by conventional standards) for RTS, most patients were able to complete all tests in the current study. A functional test battery, such as the current, therefore seems feasible to conduct six months after patellar instability surgery. But more knowledge on cut-offs for readiness clearance, and the ideal timing of such assessment, is needed. Also, it could be argued that patients with recurrent patellar instability might be better off with a return to activity rather than return to sports assessment given the heterogeneity in their activity participation.