This study measured musculoskeletal differences between an individual's residual (amputated) limb and intact (non-amputated) limb to identify structures vulnerable to injury.
The aim of this study was to measure musculoskeletal differences between an individual's residual (amputated) limb and intact (non-amputated) limb to identify structures vulnerable to injury. The results suggest residual limbs are at increased risk of muscle atrophy and femoral neck fracture compared to intact limbs. The authors hypothesized that the residual limb, compared to the intact limb, would show: 1) less muscle mass and more fat as indicators of muscle atrophy, 2) wider hip and knee joint spaces as indicators of osteoarthritis in the intact limb, and 3) decreased femoral neck width as an indicator of fracture risk. CT scans of 10 males (42-79 years) were obtained from the New Mexico Decedent Image Database. 3D Slicer software was used to measure gross skeletal properties, hip and knee joint dimensions, and cross-sectional muscle and fat tissue areas at the midshaft. A Wilcoxon Signed-Rank test was used to assess the differences between residual and intact limbs. The significance level was set at α ≤ 0.10 due to a small sample size. Compared to the intact limb, the residual limb had significantly less muscle tissue area (p=0.010) and a significantly narrower femoral neck width (p=0.077). No significant differences were found in hip or knee joint spaces between limbs. In agreement with hypotheses 1 and 3, these results suggest residual limbs are at increased risk of muscle atrophy and femoral neck fracture compared to intact limbs. Loading inequalities between the residual and intact limb likely contribute to these results. Additional data on how musculoskeletal tissues respond to unloading at multiple structural levels can improve clinical interventions for lower limb strength and function in amputees. (Published Abstract Provided)