This longitudinal study aimed to assess muscle morphological and functional changes in older patients admitted with fragility fractures managed by immobilisation of the affected limb for at least 6 weeks. Patients aged ≥ 70 hospitalised with non-weight bearing limb fractures, and functionally limited to transfers only, were recruited. Handgrip (HGS) and knee extensor strength (KES), Vastus Lateralis muscle thickness (VLMT) and cross-sectional area at ultrasound (VLCSA) were measured in the non-injured limb at hospital admission, 1, 3 and 6 weeks later. Barthel Index, mobility aid use and residential status were recorded at baseline and 16 weeks. Longitudinal changes in muscle measurements were analysed using one-way repeated measures ANOVA. In a sub-study, female patients’ baseline measurements were compared to 11 healthy, female, non-frail, non-hospitalised control volunteers (HC) with comparable BMI, aged ≥ 70, using independent t tests. Fifty patients (44 female) participated. Neither muscle strength nor muscle size changed over a 6-week immobilisation. Dependency increased significantly from pre-fracture to 16 weeks. At baseline, the patient subgroup was weaker (HGS 9.2 ± 4.7 kg vs. 19.9 ± 5.8 kg, p < 0.001; KES 4.5 ± 1.5 kg vs. 7.8 ± 1.3 kg, p < 0.001) and had lower muscle size (VLMT 1.38 ± 0.47 cm vs. 1.75 ± 0.30 cm, p = 0.02; VLCSA 8.92 ± 4.37 cm² vs. 13.35 ± 3.97 cm², p = 0.005) than HC. The associations with lower muscle strength measures but not muscle size remained statistically significant after adjustment for age. Patients with non-weight bearing fractures were weaker than HC even after accounting for age differences. Although functional dependency increased after fracture, this was not related to muscle mass or strength loss, which remained unchanged.

这项纵向研究旨在评估因脆性骨折入院的老年患者的肌肉形态和功能变化，这些患者通过将受影响的肢体固定至少 6 周进行治疗。招募了年龄≥ 70 岁、因非负重肢体骨折而住院且功能仅限于转移的患者。在入院时、1周、3周和6周后测量未受伤肢体的握力（HGS）和伸膝力量（KES）、股外侧肌厚度（VLMT）和超声横截面积（VLCSA）。在基线和 16 周时记录 Barthel 指数、助行器使用情况和居住状况。使用单向重复测量方差分析分析肌肉测量的纵向变化。在一项子研究中，使用独立t检验，将女性患者的基线测量值与 11 名健康、女性、非虚弱、非住院对照志愿者 (HC) 进行比较，这些志愿者的 BMI 相当，年龄≥ 70 岁。 50 名患者（44 名女性）参与。在 6 周的固定时间内，肌肉力量和肌肉大小都没有变化。从骨折前到 16 周，依赖性显着增加。在基线时，患者亚组较弱（HGS 9.2 ± 4.7 kg vs. 19.9 ± 5.8 kg，p  < 0.001；KES 4.5 ± 1.5 kg vs. 7.8 ± 1.3 kg，p  < 0.001）并且肌肉尺寸较小（VLMT 1.38 ± 0.47 cm 对比 1.75 ± 0.30 cm，p  = 0.02；VLCSA 8.92 ± 4.37 cm ²对比 13.35 ± 3.97 cm ²，p  = 0.005）。在调整年龄后，与较低肌肉力量测量值而非肌肉尺寸的相关性仍然具有统计学意义。即使考虑到年龄差异，非负重骨折患者的力量也比正常人弱。尽管骨折后功能依赖性增加，但这与肌肉质量或力量损失无关，肌肉质量或力量损失保持不变。