Substantial Loss of Skeletal Muscle Mass Occurs After Femoral Fragility Fracture.

BACKGROUND: Femoral fragility fractures in older adults can result in devastating loss of physical function and independence. Skeletal muscle atrophy likely contributes to disability. The purpose of this study was to characterize the change in skeletal muscle mass, investigate the relationship with malnutrition and physical function, and identify risk factors for skeletal muscle loss. METHODS: Adults ≥65 years of age who were treated with operative fixation of an isolated femoral fragility fracture were enrolled in this multicenter, prospective observational study. Skeletal muscle mass was assessed within 72 hours of admission using multifrequency bioelectrical impedance analysis, which was repeated at 6 weeks, 3 months, and 6 months. Sarcopenia was defined by sex-specific cutoffs for the appendicular skeletal muscle mass index. The Mini Nutritional Assessment was used to measure nutritional status at the time of injury. Physical function was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function domain. Linear mixed models were used to evaluate changes in skeletal muscle mass and PROMIS Physical Function scores over time and to evaluate factors associated with skeletal muscle mass changes. RESULTS: Ninety participants (74% female) with a mean age of 77.6 ± 9.0 years were enrolled. At the time of injury, 30 (33%) were sarcopenic and 44 (49%) were at risk for malnutrition or had malnutrition. Older age was associated with lower skeletal muscle mass (age of ≥75 versus <75 years: least squares mean [and standard error], -3.3 ± 1.6 kg; p = 0.042). From the time of injury to 6 weeks, participants lost an average of 2.4 kg (9%) of skeletal muscle mass (95% confidence interval [CI] = ‒3.0 to ‒1.8 kg; p < 0.001). This early loss did not recover by 6 months (1.8 kg persistent loss compared with baseline [95% CI = ‒2.5 to ‒1.1 kg]; p < 0.001). Participants with normal nutritional status lost more skeletal muscle mass from baseline to 6 weeks after injury compared with those with malnutrition (1.3 kg more loss [standard error, 0.6 kg]; p = 0.036). A 1-kg decrease in skeletal muscle mass was associated with an 8-point decrease in the PROMIS Physical Function (model parameter estimate, 0.12 [standard error, 0.04]; p = 0.002). CONCLUSIONS: We found that older adults with femoral fragility fractures lost substantial skeletal muscle mass and physical function. Participants with adequate baseline nutrition actually lost more muscle mass than those who were malnourished, indicating that future investigations of interventions to prevent muscle loss should focus on older adults regardless of nutritional status. LEVEL OF EVIDENCE: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Food Insecurity Is Common in the Orthopedic Trauma Population at a Rural Academic Trauma Center.

Background: Food insecurity is an increasingly recognized public health issue. Identifying risk factors for food insecurity would support public health initiatives to provide targeted nutrition interventions to high-risk individuals. Food insecurity has not been investigated in the orthopedic trauma population. Methods: From April 27, 2021 to June 23, 2021, we surveyed patients within six months of operative pelvic and/or extremity fracture fixation at a single institution. Food insecurity was assessed using the validated United States Department of Agriculture Household Food Insecurity questionnaire generating a food security score of 0 to 10. Patients with a food security score ≥ 3 were classified as Food Insecure (FI) and patients with a food security score < 3 were classified as Food Secure (FS). Patients also completed surveys for demographic information and food consumption. Differences between FI and FS for continuous and categorical variables were evaluated using the Wilcoxon sum rank test and Fisher's exact test, respectively. Spearman's correlation was used to describe the relationship between food security score and participant characteristics. Logistic regression was used to determine the relationship between patient demographics and odds of FI. Results: We enrolled 158 patients (48% female) with a mean age of 45.5 ± 20.3 years. Twenty-one patients (13.3%) screened positive for food insecurity (High security: n=124, 78.5%; Marginal security: n=13, 8.2%; Low security: n=12, 7.6%; Very Low security: n=9, 5.7%). Those with a household income level of ≤ $15,000 were 5.7 times more likely to be FI (95% CI 1.8-18.1). Widowed/single/divorced patients were 10.2 times more likely to be FI (95% CI 2.3-45.6). Median time to the nearest full-service grocery store was significantly longer for FI patients (t=10 minutes) than for FS patients (t=7 minutes, p=0.0202). Age (r= -0.08, p=0.327) and hours working (r= -0.10, p=0.429) demonstrated weak to no correlation with food security score. Conclusion: Food insecurity is common in the orthopedic trauma population at our rural academic trauma center. Those with lower household income and those living alone are more likely to be FI. Multicenter studies are warranted to evaluate the incidence and risk factors for food insecurity in a more diverse trauma population and to better understand its impact on patient outcomes. Level of Evidence: III.

Reliability of Multifrequency Bioelectrical Impedance Analysis to Quantify Body Composition in Patients After Musculoskeletal Trauma.

Background: Changes in body composition, especially loss of lean mass, commonly occur in the orthopedic trauma population due to physical inactivity and inadequate nutrition. The purpose of this study was to assess inter-rater and intra-rater reliability of a portable bioelectrical impedance analysis (BIA) device to measure body composition in an orthopedic trauma population after operative fracture fixation. BIA uses a weak electric current to measure impedance (resistance) in the body and uses this to calculate the components of body composition using extensively studied formulas. Methods: Twenty subjects were enrolled, up to 72 hours after operative fixation of musculoskeletal injuries and underwent body composition measurements by two independent raters. One measurement was obtained by each rater at the time of enrollment and again between 1-4 hours after the initial measurement. Reliability was assessed using intraclass correlation coefficients (ICC) and minimum detectable change (MDC) values were calculated from these results. Results: Inter-rater reliability was excellent with ICC values for body fat mass (BFM), lean body mass (LBM), skeletal muscle mass (SMM), dry lean mass (DLM), and percent body fat (PBF) of 0.993, 0.984, 0.984, 0.979, and 0.986 respectively. Intra-rater reliability was also high for BFM, LBM, SMM, DLM, and PBF, at 0.994, 0.989, 0.990, 0.983, 0.987 (rater 1) and 0.994, 0.988, 0.989, 0.985, 0.989 (rater 2). MDC values were calculated to be 4.05 kg for BFM, 4.10 kg for LBM, 2.45 kg for SMM, 1.21 kg for DLM, and 4.83% for PBF. Conclusion: Portable BIA devices are a versatile and attractive option that can reliably be used to assess body composition and changes in lean body mass in the orthopedic trauma population for both research and clinical endeavors. Level of Evidence: III.

Cellular and morphological changes with EAA supplementation before and after total knee arthroplasty.

Investigate the underlying cellular basis of muscle atrophy (Placebo) and atrophy reduction (essential amino acid supplementation, EAAs) in total knee arthroplasty (TKA) patients by examining satellite cells and other key histological markers of inflammation, recovery, and fibrosis. Forty-one subjects (53-76 yr) scheduled for TKA were randomized into two groups, ingesting 20 g of EAAs or placebo, twice-daily, for 7 days before TKA and for 6 wk after surgery. A first set of muscle biopsies was obtained from both legs before surgery in the operating room, and patients were randomly assigned and equally allocated to have two additional biopsies at either 1 or 2 wk after surgery. Biopsies were processed for gene expression and immunohistochemistry. Satellite cells were significantly higher in patients ingesting 20 g of essential amino acids twice daily for the 7 days leading up to surgery compared with Placebo (operative leg P = 0.03 for satellite cells/fiber and P = 0.05 for satellite cell proportions for Type I-associated cells and P = 0.05 for satellite cells/fiber for Type II-associated cells.) Myogenic regulatory factor gene expression was different between groups, with the Placebo Group having elevated MyoD expression at 1 wk and EAAs having elevated myogenin expression at 1 wk. M1 macrophages were more prevalent in Placebo than the EAAs Group. IL-6 and TNF-α transcripts were elevated postsurgery in both groups; however, TNF-α declined by 2 wk in the EAAs Group. EAAs starting 7 days before surgery increased satellite cells on the day of surgery and promoted a more favorable inflammatory environment postsurgery.NEW & NOTEWORTHY Clinical studies by our group indicate that the majority of muscle atrophy after total knee arthroplasty (TKA) in older adults occurs rapidly, within the first 2 wks. We have also shown that essential amino acid supplementation (EAAs) before and after TKA mitigates muscle atrophy; however, the mechanisms are unknown. These results suggest that satellite cell numbers are elevated with EAA ingestion before surgery, and after surgery, EAA ingestion positively influences markers of inflammation. Combined, these data may help inform further studies designed to address the accelerated sarcopenia that occurs in older adults after major surgery.

Essential Amino Acid Supplementation Mitigates Muscle Atrophy After Total Knee Arthroplasty: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Substantial muscle atrophy occurs after total knee arthroplasty (TKA), resulting in decreased strength and impaired mobility. We sought to determine whether perioperative supplementation with essential amino acids (EAA) would attenuate muscle atrophy following TKA and whether the supplements were safe for ingestion in an older surgical population. METHODS: We performed a double-blind, placebo-controlled, randomized trial of 39 adults (age range, 53 to 76 years) undergoing primary unilateral TKA who ingested 20 g of EAA (n = 19) or placebo (n = 20) twice daily for 7 days preoperatively and for 6 weeks postoperatively. At baseline and 6 weeks postoperatively, magnetic resonance imaging (MRI) scans were obtained to measure quadriceps and hamstrings muscle volume. Secondary outcomes included functional mobility and strength. Data on physical activity, diet, and patient-reported outcomes (Veterans RAND 12-Item Health Survey and Knee injury and Osteoarthritis Outcome Score) were collected. Safety was determined through blood tests evaluating blood urea nitrogen, creatinine, creatinine clearance, homocysteine, and renal and liver function. Laboratory values at baseline, on the day of surgery, and at 2 days, 2 weeks, and 6 weeks postoperatively were compared between treatment groups. Analysis of covariance models, with baseline values as covariates, were used to evaluate outcomes between treatment groups. P values were adjusted for multiple tests. RESULTS: Compared with baseline, the EAA group had significantly less decrease in mean quadriceps muscle volume compared with the placebo group in the involved leg (-8.5% ± 2.5% compared with -13.4% ± 1.9%; p = 0.033) and the contralateral leg (-1.5% ± 1.6% compared with -7.2% ± 1.4%; p = 0.014). The hamstrings also demonstrated a greater muscle-volume-sparing effect for the EAA group than for the placebo group in the involved leg (-7.4% ± 2.0% compared with -12.2% ± 1.4%; p = 0.036) and contralateral leg (-2.1% ± 1.3% compared with -7.5% ± 1.5%; p = 0.005). There were no differences between the groups in terms of functional measures or strength. Blood chemistry values varied significantly between assessments periods but did not statistically differ between groups. CONCLUSIONS: The results of the present study suggest that EAA supplementation is safe and reduces the loss of muscle volume in older adults recovering from TKA. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.