Biomechanical outcomes of through-knee amputation for implications in surgical decision-making, prosthetic socket design and long-term health

Abstract

Major lower limb amputations (MLLA) are common in dysvascular and trauma populations. Amputation at the level of the knee (also known as through-knee amputation or knee disarticulation (TKA)) represents a very small proportion of all MLLA, with transfemoral amputation (TFA) usually considered the preferred alternative. However, TKA presents many theoretical biomechanical advantages, but objective biomechanical measures are rarely reported. The aim of this thesis was to investigate the gait biomechanics of people with TKA and compare them to people with TFA and able-bodied controls. A review of the different surgical techniques for TKA and the reported surgical, functional, and biomechanical outcomes was performed. The kinematics and kinetics during walking were compared for four TKA, seven TFA and nine control non-amputated participants. Musculoskeletal modelling was used to estimate joint contact forces (JCF) and muscle forces and activity for TKA and controls. Differences in knee, hip and pelvis kinematics and kinetics were observed between TFA and TKA, with TKA having fewer differences than TFA compared with controls. There were no differences in muscle forces between people with TKA and controls other than at the hip extensors. There were no differences in peak JCF at any joint between both legs of TKA and able-bodied controls but there were differences in timing. The improved understanding of the biomechanics of TKA provided from this thesis can be used to adjust rehabilitation strategies and prosthetic design to improve the patients’ long-term outcomes. Our findings suggested that TKA should be considered when performing MLLA and when TTA is not feasible because they may have a reduced risk of developing secondary conditions compared to TFA. More research is needed to broadly generalize these results and evaluate other outcomes such as surgical and long-term functional and health outcomes.