The Effect of Preoperative Nutritional Status and Muscle Quality on Functional Recovery in Patients With Hip Fractures

PURPOSE: Functional recovery after a hip fracture is closely related to nutrition; however, the factors with the strongest influence on early postoperative mobility remain unclear. We aimed to investigate whether preoperative muscle quality (intramuscular adipose tissue content [IMAC]) and phase angle (PhA) are associated with short-term (2-week) functional recovery, and to compare their associations with those of muscle mass. METHODS: We retrospectively reviewed 87 patients with hip fractures who could walk before their injury and divided them into two groups: Group A (n = 43), individuals without a decline in walking ability at discharge compared with pre-fracture status, and Group B (n = 44), individuals whose walking ability declined postoperatively. All participants underwent bioelectrical impedance analysis and computed tomography on admission. PhA, psoas muscle index (PMI), and IMAC were measured, and the ΔFIM (difference between admission and two postoperative weeks) was calculated. Between-group comparisons and Spearman's correlation analyses were performed. RESULTS: PhA was significantly higher in Group A (4.3° ± 0.9°) than in Group B (3.6° ± 0.7°; p < 0.0005). IMAC was significantly lower in Group A (-0.2 ± 0.4) than in Group B (0.4 ± 0.3; p < 0.0005). Δ walking score was significantly correlated with IMAC (ρ = -0.399; p = 0.000139) and PhA (ρ = 0.275; p = 0.01). In multivariate logistic regression, IMAC was the only variable independently associated with walking recovery (p = 0.049). Furthermore, ΔFIM correlated positively with PhA (ρ = 0.24; p < 0.05), while IMAC showed no significant correlation with ΔFIM. CONCLUSION: Preoperative IMAC and PhA may be useful indicators of short-term postoperative functional recovery, with IMAC showing a particularly strong association with ambulation recovery. These findings highlight the clinical relevance of muscle quality and nutritional assessment, although the evaluation at only two postoperative weeks represents a limitation.