RESUMEN
BACKGROUND: Transmission of loads between the prosthetic socket and the residual limb is critical for the comfort and walking ability of people with transfemoral amputation. This transmission is mainly determined by the socket tightening, muscle forces, and socket ischial support. However, numerical investigations of the amputated gait, using modeling approaches such as MusculoSkeletal (MSK) modeling, ignore the weight-bearing role of the ischial support. This simplification may lead to errors in the muscle force estimation. OBJECTIVE: This study aims to propose a MSK model of the amputated gait that accounts for the interaction between the body and the ischial support for the estimation of the muscle forces of 13 subjects with unilateral transfemoral amputation. METHODS: Contrary to previous studies on the amputated gait which ignored the interaction with the ischial support, here, the contact on the ischial support was included in the external loads acting on the pelvis in a MSK model of the amputated gait. RESULTS: Including the ischial support induced an increase in the activity of the main abductor muscles, while adductor muscles' activity was reduced. These results suggest that neglecting the interaction with the ischial support leads to erroneous muscle force distribution considering the gait of people with transfemoral amputation. Although subjects with various bone geometries, particularly femur lengths, were included in the study, similar results were obtained for all subjects. CONCLUSIONS: Eventually, the estimation of muscle forces from MSK models could be used in combination with finite element models to provide quantitative data for the design of prosthetic sockets.
RESUMEN
OBJECTIVES: Through-knee amputation is an umbrella term for several different surgical techniques, which may affect clinical and functional outcomes. This makes it hard to evaluate the benefits and need for a through-knee amputation approach. This article seeks to (1) determine the number of through-knee amputation performed compared with other major lower limb amputations in England over the past decade; (2) identify the theoretical concepts behind through-knee amputation surgical approaches and their potential effect on functional and clinical outcomes and (3) provide a platform for discussion and research on through-knee amputation and surgical outcomes. METHODS: National Health Service Hospital Episodes Statistics were used to obtain recent numbers of major lower limb amputations in England. EMBASE and MEDLINE were searched using a systematic approach with predefined criteria for relevant literature on through-knee amputation surgery. RESULTS: In the past decade, 4.6% of major lower limb amputations in England were through-knee amputations. Twenty-six articles presenting through-knee amputation surgical techniques met our criteria. These articles detailed three through-knee amputation surgical techniques: the classical approach, which keeps the femur intact and retains the patella; the Mazet technique, which shaves the femoral condyles into a box shape and the Gritti-Stokes technique, which divides the femur proximal to the level of the condyles and attaches the patella at the distal cut femur. CONCLUSIONS: Through-knee amputation has persisted as a surgical approach over the past decade, with three core approaches identified. Studies reporting clinical, functional and biomechanical outcomes of through-knee amputation frequently fail to distinguish between the three distinct and differing approaches, making direct comparisons difficult. Future studies that compare through-knee amputation approaches to one another and to other amputation levels are needed.
