¹Woeber N, ²Triplett A, ³Kuenze
¹Michigan State University College of Osteopathic Medicine, Holt, MI, United States; ²Michigan State University , East Lansing , MI, United States ; ³Michigan State University, East Lansing, MI, United States

More than 125,000 anterior cruciate ligament reconstructions (ACLR) are performed annually in the United States. ACLR typically requires 6-9 months of rehabilitation, often resulting in prolonged periods of sedentary activity due to inability to participate in sport. Recent studies have shown that individuals with ACLR are 2.4 times less likely to meet weekly recommendations for physical activity (PA) compared to healthy controls. Additionally, it has been reported that body mass index (BMI) remains elevated for up to two years post-ACLR, and limited evidence suggests individuals with ACLR may have more percent body fat than healthy controls.

PURPOSE: To compare body composition, cardiorespiratory fitness (CRF), and PA engagement between individuals with ACLR and uninjured controls.

METHODS: Sixteen individuals with ACLR (months since surgery=36.3 +/-19.0; age=21.8+/-3.2 years) and 8 uninjured individuals (age=22.8 +/- 3.5yrs) matched based on age (+/-1yrs), sex, and Tegner Activity Level (+/-1) participated. Body fat percentage (%BF) was estimated using air displacement plethysmography, CRF was assessed via a graded treadmill test, and PA was assessed using accelerometers worn for 7 days. Groups were compared using Mann-Whitney U tests. Time (mins/week) spent in moderate-to-vigorous PA (MVPA) and step count (steps/day) were compared between groups using a one-way ANCOVA with 7-day total wear time as the only covariate.

RESULTS: Individuals with a history of ACLR had greater body mass (p=0.01), BMI (p<0.01), and fat mass (p=0.02) compared to uninjured individuals. No differences were observed for %BF (p=0.19), fat free mass (p=0.07), MVPA (mins/week) (p=0.28) or daily step count (p=0.38) between groups. Participants with a history of ACLR had significantly shorter treadmill time to exhaustion as compared to uninjured participants (p=0.04). There were no differences observed between groups for VO2peak (p=0.24).

CONCLUSION: This pilot study indicates that individuals with ACLR display similar characteristics of cardiovascular health as their uninjured peers, but those with ACLR may experience elevated BMI and fat mass and end a maximal graded exercise test sooner. Given that ACLR is most common in individuals under the age of 30, and that ACLR rates have been rising over the last 20 years, these results emphasize the need for further investigation of the effects of ACLR on cardiovascular health and body composition. The time following ACLR provides an opportunity for clinicians to promote healthy behaviors, including PA and diet, to their patients to ensure that ACLR does not become a risk factor for cardiovascular disease.

References:

1. Bell DR et al. Objectively Measured Physical Activity in Patients After Anterior Cruciate Ligament Reconstruction. Am J Sports Med. 2017;45(8):1893-1900.
2. Dunn et al. Predictors of activity level two years after ACL reconstruction: MOON ACLR cohort study. Am J Sports Med. 2010; 38(10): 2040-2050.
3. MacAlpine et al. Weight gain after ACL reconstruction in pediatric and adolescent patients. Sports Health. 2019.
4. Mall NA et al. Incidence and Trends of Anterior Cruciate Ligament Reconstruction in the United States. Am J Sports Med. 2014;42(10):2363-2370.