Limb symmetry index and pre-injury performance level after anterior cruciate ligament reconstruction: A case report on a female gymnast

Background Functional performance tests serve to monitor the injured leg's resilience after anterior cruciate ligament injuries. The limb symmetry index greater than or equal to 90% represents an objective criterion to evaluate the knee function restoration and to return to sports. Aims The aim was to detect the point in time when limb symmetries and pre-injury levels of performance were restored, during the first year after surgery. Based on the data obtained, the proper moment for return to sport readiness was identified. Methods A 25-year-old female competitive gymnast performed a single-leg functional test battery. The study was conducted over 24 months and included one pre-injury and seven post-injury sessions. Results Inter-limb symmetries were restored at eight-ten months in all tests. Pre-injury performance levels were achieved at six months in two out of four tests. The single-leg hop for distance showed a performance decrease greater than 20% in the injured leg at twelve months. Conclusion Return to sport readiness was identified at ten months after surgery. Nevertheless, the restored inter-limb symmetry does not take into account performance decreases in the single-leg hop for distance and y-balance tests. Therefore, regular baseline assessments are recommendable to provide data for comparison and to optimise the decision-making process after injury.