Assessing the Role of the Socket Trim Line on Reactive Balance in People with Transfemoral Amputation
Abstract
Over 50% of people with amputation fall annually, and that fall risk is generally higher in people with transfemoral amputation. Despite the high prevalence of falls, very little is known about fall risk factors specific to prosthetics users and even less is known for person with transfemoral amputation (TFA). In response to a loss of balance, a fall to the ground is inevitable unless a person can properly react to the loss of balance. One of the most common ways of doing so involves taking a protective step. When protective steps are needed to recover a sideways directed loss of balance, the effectiveness of these steps is strongly dependent on strength and coordination of the hip muscle on the side of the leg. We argue that the ability of people with TFA to engage these muscles, and thus to prevent certain falls, can be impacted by how high the socket comes up the leg (i.e., the socket trim). Using sockets with high trim lines (e.g., ones that encapsulate the sit bones) may compress the muscles on the side of the hip to a greater extent than sockets with lower (below the sit bones) trim lines, which may prevent these muscles from bulging and producing forces when they contract. Accordingly, even if a person with TFA has the underlying capacity to enact a protective step that would avoid a fall following a given level of destabilizing force, they may still fall in response to that force if their socket prevents them from attaining that capacity (something that we term socket interference). The objective of the proposed work is to provide preliminary evidence that socket trim can impact fall risk in lower functioning people with TFA. Namely, we seek to demonstrate that reactive stepping responses after experiencing sideways directed destabilizing forces are biomechanically less effective in lower functioning people with TFA using sockets with high trim lines and that high trim lines interfere with hip function to a greater extent than do lower trim lines. The proposed study is the first step in a line of research with the long-term goal of promoting enduring improvements in physical and mental health of lower functioning prosthetic users by reducing the prevalence and burden of falls. Once we develop a complete understanding of how socket trim line impacts hip muscle function, particularly as it relates to reactive balance tasks in a group at high risk of falls, we can then guide clinical practice to help address this risk. In particular, we hope to be able to identify individuals in whom socket interference is a primary contributor to impaired stepping responses and increased fall risk and who would be expected to show immediate improvements in these measures by adjusting the trim line. Such improvement may be furthered by inclusion of physical therapy-based interventions (e.g., strength and balance training), which have been shown to improve reactive stepping and reduce falls in older adults without amputation. Such interventions would also be an appropriate initial step to preventing falls in individuals who do not currently have the underlying capacity to benefit from changes in socket trim. Thus, the initial short-term impact of the work involves providing new knowledge to the field regarding the role of hip muscles and socket interference in reactive balance and falls by lower functioning people with TFA, with the long-term impact of reducing falls and positively impacting patients’ quality of life. Following successful completion of the proposed work, we anticipate that an additional 4 years would be needed to conduct the studies needed to move from the short-term to the long-term goals. The proposed work is intended to benefit Service Members, Veterans, and/or other beneficiaries with limb loss and/or limb impairment who are lower functioning and at high risk of falls. A recent study evaluating amputations across all Veteran healthcare centers from 1999 to 2018 reported 21,315 transfemoral amputations, of
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 28, 2022
- Source ID
- W81XWH2210140
Entities
People
- Noah Rosenblatt
Organizations
- Rosalind Franklin University of Medicine and Science
- United States Army