Background: Persons with transfemoral amputation typically have severe muscle atrophy of the residual limb. The effect of bone-anchored prosthesis use on existing muscle atrophy is unknown. A potentially feasible method to evaluate this is magnetic resonance imaging (MRI)-based three-dimensional (3D) muscle reconstruction. We aimed to (1) examine the feasibility of MRI-based 3D muscle reconstruction technique in a person with a cobalt-chrome-molybdenum transfemoral bone-anchored prosthesis; and (2) describe the change of hip abductor muscle volume over time.
Methods: In this single case, 1-year follow-up study we reconstructed the 3D hip abductor muscle volumes semiautomatically from MRI scans at baseline, 6- and 12-month follow-up. The number of adverse events, difficulties in data analysis, time investment and participants' burden determined the level of feasibility.
Results: We included a man (70 years) with a transfemoral amputation who received a bone-anchored prosthesis after 52 years of socket prosthesis use. No adverse events occurred. The accuracy of the 3D reconstruction was potentially reduced by severe adipose tissue interposition. Data analysis was time-intensive (115 h). Participants' burden was limited to 3-h time investment. Compared to baseline, the total hip abductor volume of both the residual limb (6 month: 5.5%; 12 month: 7.4%) and sound limb (6 month: 7.8%; 12 month: 5.5%) increased.
Conclusion: The presented technique appears feasible to follow muscle volume changes over time in a person with a cobalt-chrome-molybdenum transfemoral bone-anchored prosthesis in an experimental setting. Future research should focus on analysis of muscle tissue composition and the feasibility in bone-anchored prostheses of other alloys.
Keywords: Amputees; artificial limbs; magnetic resonance imaging; osseointegration; three-dimensional reconstruction.