LAUSR

INTRODUCTION The influence of graft type on the restoration of quadriceps strength symmetry following ACL reconstruction (ACLR) has been widely studied. However, an important consideration when evaluating quadriceps symmetry is the fact that this measure can be influenced by numerous factors beyond graft type. This study sought to determine if graft type is predictive of quadriceps strength asymmetry during the first 12 months post ACLR taking into consideration potentially influential factors (i.e., age, sex, BMI, time post ACLR). METHODS We retrospectively reviewed quadriceps strength data from 434 patients (303 females and 131 males) who had previously undergone ACLR with an autograft (hamstring tendon (HT), quadriceps tendon (QT), patellar tendon (PT)) or allograft. Chi-squared Automatic Interaction Detection (CHAID) decision tree analysis was used to evaluate how graft type influenced quadriceps strength asymmetry during the first 12 months post ACLR taking into consideration age, sex, BMI, and time post ACLR. RESULTS The best predictor of quadriceps strength asymmetry was graft type. Specifically, 3 graft categories were identified (1) allograft and HT autograft, (2) PT autograft, and (3) QT autograft. The average quadriceps strength asymmetry for each of the 3 identified categories was 0.91, 0.87, and 0.81, respectively, and differed statistically from each other (p < 0.001). The second-best predictor of quadriceps strength asymmetry was sex, albeit only in the PT and QT groups (with females having increased asymmetry). Female patients post ACLR with a QT autograft were at highest risk for quadriceps strength asymmetry. CONCLUSIONS Graft type and sex are important predictors of quadriceps strength asymmetry following ACLR. Clinicians should take these factors into consideration when designing rehabilitation protocols to restore quadriceps strength symmetry during the post-operative period.