Predictors of Physical Activity Early After Anterior Cruciate Ligament Reconstruction

Context Individuals often demonstrate reduced physical activity (PA) between 6 months and 5 years after anterior cruciate ligament reconstruction (ACLR), but little is known about PA levels during the first 6 months postoperatively. Objective To identify factors that predict PA in this early period. Design Prospective cohort study. Setting Participants were recruited from an academic health science center and a private sports medicine clinic and assessed in a clinical and research setting. Patients or Other Participants Sixty-three participants aged 13 to 35 years who underwent ACLR (19.6 ± 5.0 years; 55.6% female). Main Outcome Measure(s) Daily step counts and moderate-to-vigorous PA (MVPA) were assessed with a 3-axis accelerometer for 7 consecutive days during waking hours at 4 and 6 months after ACLR. The Tampa Scale of Kinesiophobia (TSK-11), International Knee Documentation Committee Subjective Knee Form (IKDC), and quadriceps strength were assessed at each time point. Graft type and meniscus repair status were extracted from operative reports, whereas sex was self-reported. Multiple linear regression was used to determine associations between these variables and PA outcomes. Results At 6 months, the combination of sex, TSK-11, IKDC, graft type, meniscus repair status, and quadriceps strength was significantly associated with daily steps ( R 2 = 0.260, adjusted R 2 = 0.147, P = .042). This group of variables was also associated with MVPA at both 4 months ( R 2 = 0.249, adjusted R = 0.142, P = .040) and 6 months ( R 2 = 0.272, adjusted R 2 = 0.162, P = .031). However, no individual factor was a significant predictor of PA at either time point (all P s > .05). Conclusions Several clinical and demographic factors were collectively associated with early PA after ACLR, but they explained only a small portion of the variance. Additional factors likely influence early recovery, and further research is needed to understand their role and the long-term impact of early PA.