Medial-lateral margin of stability for the comparison of two bone-anchored prostheses – a case study

Assessing the functional ability depending on the prosthesis fitting of individuals with transfemoral amputation (TFA) is critical for overall rehabilitation and prosthetic care. Gait analysis could provide an overwhelming number of biomechanical parameters. We argue that margins of stability (MoS) could be critical indicators of TFA’s control strategy. A study revealed statistically larger MoS on the prosthetic limb when comparing medial-lateral MoS for six TFAs fitted with a socket-suspended prostheses and six able- bodied during treadmill walking (Hof et al. 2007). Another study showed limited and non-significant differences when comparing anterior-posterior MoS for ten TFA fitted with mechanical and microprocessor-controlled knees during walking overground (Prinsen et al. 2017). There is a need to report MoS more widely, particularly for TFA fitted with bone-anchored prosthesis as osseoperception should improve control. A single case study demonstrated that the load applied by bone-anchored prosthesis fitted with microprocessor-controlled was attenuated by 10-20% compared to mechanical knee (Frossard et al. 2013). However, the impact of these loading differences on the overall gait pattern, including medial-lateral MoS, remains unknown.