Summary

The non-operative limb outperformed the operative limb for the 6-metre timed, triple-hop for distance and triple cross-over hop tests 24-months following ACL reconstruction, and correlated to the disease-specific, patient-reported ACL-QOL score.

Abstract

Purpose

The aim of an anterior cruciate ligament (ACL) reconstruction is to regain functional stability of the knee following ACL injury, ideally allowing patients to return to their pre-injury level of activity. The purpose of this study was to assess functional and patient-reported outcomes 2-years after ACL reconstruction.

Methods

A prospective cohort study design (n = 1241) was used to gather functional performance data and disease-specific quality of life outcomes. A battery of functional tests was performed including single leg balance on a BOSU ball, single leg drop landing, and 4 single-leg hop tests. The hop tests provided a comparative assessment of limb-to-limb function including a single hop for distance, a 6-metre timed hop, a triple hop for distance, and a triple crossover hop. Patients completed the anterior cruciate ligament quality of life questionnaire (ACL-QOL) at the 2-year post-operative appointment. Descriptive and demographic data were collected for all patients. A paired t-test was performed to determine the difference in function of the operative and non-operative limbs 2-year post-operatively on the functional tests.
A Pearson r correlation coefficient was employed to determine the relationship between the battery of functional tests and the ACL-QOL scores.

Results

1241 patients underwent primary anatomic hamstring ACL reconstruction between January 2010 and December 2013. 964/1241 patients (77.7%) completed 2-year follow-up. Statistically significant differences (p < 0.002) were evident between the operative and non-operative limb 6-metre timed-hop, triple-hop for distance and triple cross-over hop tests at 24-months post-operative. There was no significant difference for limb performance on the single hop test. Correlations (2-tailed) were significant at the 0.01 level for: operative limb single-leg BOSU balance and operative limb 6-metre timed hop, triple-hop for distance and triple cross-over hop, as well as operative single-leg BOSU balance and ACL-QOL score, at 24-months post-operative. Correlations (2-tailed) were significant at the 0.05 level for: triple-hop for distance and 6m timed hop and triple cross-over hop, as well as triple-hop for distance and ACL-QOL score, at 24-months post-operatively.

Conclusions

The non-operative limb outperformed the operative limb for the 6-metre timed, triple hop for distance and triple cross-over hop tests 24-months following ACL reconstruction. The single hop for distance did not demonstrate any significant functional difference between limbs, and requires further investigation as a measure for assessing outcomes following ACL reconstruction. The patient-reported disease-specific outcome measure (ACL-QOL) was strongly correlated to the patient’s ability to perform single-limb balance and hop tests, indicating that the ACL-QOL score accurately represented function 2-years after ACL reconstruction.