Change in Body Weight and Body Mass Index of Adolescents and Adults From Pre-Surgery to Post-Anterior Cruciate Ligament Reconstruction

BACKGROUND: Physical activity (PA) participation can moderate weight status and body mass index (BMI), with reduced PA being associated with weight gain and elevated BMI. Previous studies have observed lower PA engagement among individuals with a history of anterior cruciate ligament reconstruction (ACLR) when compared to their uninjured peers. This reduction in PA may be due to activity limitations during rehabilitation and failure of some patients to return to sport. Limited evidence has also shown an increase in body weight and BMI following surgery that may remain elevated in adolescent patients up to 2 years post-ACLR. Overall, body weight and BMI changes from pre-surgery to post-ACLR for adolescents and adults are not well-understood. PURPOSE: The purpose of this study was to assess change in body weight and BMI from pre-surgery to 6 months post-ACLR in adolescent and adult patients. METHODS: A retrospective chart review was conducted including adult (age ≥20) and adolescent (ages 13-19) patients who underwent primary, unilateral ACLR and were previously enrolled in a prospective cohort study. BMI was calculated [weight (kg)/ height (m(2))] for all adult participants and BMI percentile was calculated for all participants under the age of 20 to account for changes in growth and maturation during adolescence. Pre-surgery to 6-months post-ACLR values for body mass, absolute BMI, and BMI percentile were compared using paired sample t-tests. Statistical significance was established a priori as α≤0.05. RESULTS: One hundred and 16 adolescents with ACLR (67 female; age= 16.7 ± 1.6yrs, months since surgery= 6.2 ± 0.7) and 63 adults (29 female; age= 27.2 ± 7.4yrs, months since surgery= 6.4 ± 0.7) participated. Adolescent participants experienced a significant increase in body mass (pre-ACLR= 70.1 ± 15.1kg, post-ACLR= 72.4 ± 16.9kg; p<0.001) and BMI percentile (pre-ACLR= 65 ± 25, post-ACLR= 67 ± 25; p=0.02) from pre-surgery to 6 months post-ACLR. Adult patients also experienced a significant increase in body mass (pre-ACLR= 80.2 ± 19.9kg, post-ACLR= 82.1 ± 20.1kg; p<0.001) and BMI (pre-ACLR= 26.1 ± 4.5kg/m(2), post-ACLR= 26.7 ± 4.9kg/m(2); p=0.006). CONCLUSION: Adults and adolescents experienced an increase in body weight and BMI in the 6 months following ACLR. Revising rehabilitation to extend beyond traditional musculoskeletal strengthening to include focus on incorporation and maintenance of healthy lifestyle behaviors related to diet and PA should be considered to help patients with ACLR to minimize the potential for negative long-term effects of weight gain following surgery.