Obesity and musculoskeletal pain are strongly related, but there is emerging evidence that body fat, not body weight, may be a better indicator of risk. There is, therefore, a need to determine if body fat is associated with musculoskeletal pain as it may improve management strategies. The aim of this systematic review was to investigate the association between body fat and musculoskeletal pain. Seven electronic databases were searched from inception to 8th January 2018. Cross-sectional and longitudinal studies investigating the association between measures of body fat and musculoskeletal pain were included. All included articles were assessed for methodological rigour using the Epidemiology Appraisal Instrument. Standardised mean differences (SMDs) and effect estimates were pooled for meta-analysis. A total of 10,221 citations were identified through the database searching, which after abstract and full-text review, yielded 28 unique articles. Fourteen studies were included in the meta-analyses, which found significant cross-sectional associations between total body fat mass and widespread pain (SMD 0.49, 95% CI 0.37–0.61, p < 0.001). Individuals with low-back pain and knee pain had a higher body fat percentage than asymptomatic controls (SMD 0.34, 95% CI 0.17–0.52, p < 0.001 and SMD 0.18, 95% CI 0.05–0.32, p = 0.009, respectively). Fat mass index was significantly, albeit weakly, associated with foot pain (SMD 0.05, 95% CI 0.03–0.06, p < 0.001). Longitudinal studies (n = 8) were unsuitable for meta-analysis, but were largely indicative of elevated body fat increasing the risk of incident and worsening joint pain. There was conflicting evidence for an association between body fat percentage and incident low-back pain (3 studies, follow-up 4–20 years). Increasing knee pain (1 study) and incident foot pain (2 studies) were positively associated with body fat percentage and fat mass index. The percentage of items in the EAI graded as ‘yes’ for each study ranged from 23 to 85%, indicating variable methodological quality of the included studies. This systematic review and meta-analysis identified positive cross-sectional associations between increased body fat and widespread and single-site joint pain in the low-back, knee and foot. Longitudinal studies suggest elevated body fat may infer increased risk of incident and worsening joint pain, although further high-quality studies are required.

Study Design: Systematic review. Background: Despite improvements in self-reported symptoms and perceived functional ability after total hip arthroplasty (THA) and total knee arthroplasty (TKA), it is unclear whether changes in objectively measured physical activity (PA) occur after surgery. Objective: To determine if objectively measured PA increases after THA and TKA in adults with osteoarthritis. Methods: Five electronic databases were searched from inception to March 3, 2015. All study designs objectively measuring PA before and after THA or TKA were eligible, including randomized controlled trials, cohort studies, and case-control studies. Two reviewers independently screened abstracts and full texts and extracted study demographic, PA, and clinical outcome data. Standardized mean differences (SMDs) and 95% confidence intervals were calculated for accelerometer- and pedometer-derived estimates of PA. Risk of methodological bias was assessed with Critical Appraisal Skills Programme checklists. Results: Eight studies with a total of 373 participants (238 TKA, 135 THA) were included. Findings were mixed regarding improvement in objectively measured PA at 6 months after THA (SMDs, −0.20 to 1.80) and TKA (SMDs, −0.36 to 0.63). Larger improvements from 2 studies at 1 year postsurgery were generally observed after THA (SMDs, 0.39 to 0.79) and TKA (SMDs, 0.10 to 0.85). However, at 1 year, PA levels were still considerably lower than those of healthy controls (THA SMDs, −0.25 to −0.77; TKA SMDs, −1.46 to −1.80). Risk-of-bias scores ranged from 3 to 9 out of 11 (27%–82%) for cohort studies, and from 3 to 8 out of 10 (30%–80%) for case-control studies. Conclusion: The best available evidence indicates negligible changes in PA at 6 months after THA or TKA, with limited evidence for larger changes at 1 year after surgery. In the 4 studies that reported control-group data, postoperative PA levels were still considerably less than those of healthy controls. Improved perioperative strategies to instill behavioral change are required to narrow the gap between patient-perceived functional improvement and the actual amount of PA undertaken after THA and TKA. Registered with PROSPERO (registration number CRD42014010155). Level of Evidence: Therapy, level 2a. J Orthop Sports Phys Ther 2016;46(6):431–442. Epub 26 Apr 2016. doi:10.2519/jospt.2016.6449