Musculoskeletal Asymmetry in Individuals with Lower Limb Amputation

Purpose: Individuals with lower limb amputation experience differences in musculoskeletal loading that can lead to gait asymmetries, increased fall risk, and overuse injuries. This study investigates how lower limb amputation affects musculoskeletal properties. Cadaver assessment provides the ability to examine long-term asymmetrical loading that can be difficult to examine in living individuals. Methods: Five male unembalmed donors (61-81 years of age) with various levels of lower limb amputation were obtained through the UNTHSC Willed Body Program. Dual-energy x-ray absorptiometry, x-ray, and gross dissection were performed to collect musculoskeletal properties related to biomechanical loading during locomotion. Percent differences between limbs were calculated to assess the degree of asymmetry. Results: Each subject's most compromised side showed lower bone mineral density (19.3-36.6%) and bone mineral content (11.5-64.5%), higher tissue fat (38.8-51.8%), and wider knee joint space (9.1-53.3%), which is consistent with previous research, and a larger biceps femoris long head physiological cross-sectional area (PCSA) (18.1-68.6%). PCSA differences were inconsistent in the gluteus maximus (37.1-60.4%), rectus femoris (22.5-66.1%), and sartorius (1.4-33.9%). Differences less than 10% were found in acetabular joint space and femoral midshaft width. Conclusions: Able-bodied asymmetry is a limb difference greater than 10%. Larger musculoskeletal asymmetries of up to 68% were observed in individuals with amputation, denoting asymmetrical biomechanical loading and possibly compensations related to prosthesis use. Observed consistencies in asymmetry can be used in rehabilitation techniques to reduce the risk of falling and developing overuse injuries.