Abstract
CONTEXT: Recovery after anterior cruciate ligament reconstruction (ACLR) can lead to weight gain and reduced physical activity (PA), potentially increasing long-term health risks. Understanding the relationship between PA patterns and weight changes after ACLR is essential for optimizing rehabilitation strategies. OBJECTIVE: To examine the relationship between PA patterns and weight changes in the first 6 months after ACLR. We hypothesized that lower PA levels and longer sedentary time would predict greater weight gain. DESIGN: Case series. SETTING: Academic hospital and private sports medicine clinic. PATIENTS OR OTHER PARTICIPANTS: A total of 61 individuals (34 females, 27 males; age range, 13-35 years, body mass index < 35) who underwent primary ACLR was included. All participants received an autograft, could have undergone a concomitant meniscal repair, and had no extended weightbearing restrictions. MAIN OUTCOME MEASURES: Body weight was measured preoperatively and at 10.4 ± 2.4 weeks (early phase) and 26.9 ± 2.6 weeks (midphase) after ACLR. We assessed PA levels, including daily steps, moderate to vigorous PA (MVPA), and sedentary behavior, using accelerometry. A 2-way mixed (time × sex) analysis of variance was used to analyze weight changes, and logistic regressions were used to evaluate whether early- and midphase PA levels, age, and sex predicted weight gain (≥5%) after ACLR. RESULTS: Males gained more weight (3.4 ± 4.6 kg; P < .001) than females (1.1 ± 2.9 kg; P = .03). Logistic regression models for all PA levels predicted a gain of ≥5% body weight at early (daily steps: χ32 = 11.231, P = .01; daily MVPA: χ32 = 12.843, P = .005; and daily sedentary behavior: χ32 = 10.794, P = .01) and midphase (daily steps: χ32 = 10.320, P = .02; daily MVPA: χ32 = 12.451, P = .006; and daily sedentary behavior: χ32 = 10.003, P = .02). Males had 5.407 to 10.025 times higher odds of ≥5% weight gain than females. However, PA, sedentary behavior, and age did not predict weight gain. CONCLUSIONS: Weight gain is common 6 months after ACLR, with males experiencing greater increases than females. Although PA and sedentary behavior did not predict weight changes, incorporating targeted weight-management strategies, including nutritional and metabolic health interventions, into ACLR rehabilitation may help optimize recovery.