The effect of the transfemoral prosthetic socket interface designs on skeletal motion and socket comfort

Abstract

Background: The most crucial aspect of a prosthesis is the socket, as it will directly determine gait stability and quality. The current standard of care ischial ramus containment socket is reported to increase coronal stability through gait; however, socket discomfort is the primary complaint among prosthetic users. Objectives: The purpose of this study is to compare ischial ramus containment to alternatives in the transfemoral amputee population. All subjects were fit with three different sockets: traditional ischial ramus containment, a dynamic socket, and a sub-ischial. In this study, authors hypothesized socket skeletal motion would be equivalent across interventions. Study Design: Single-blind, repeated-measures, three-period randomized crossover clinical trial. Methods: Outcome measures were socket comfort score and skeletal motion, viewed coronally with X-ray measuring the position of the skeleton in relationship to the socket in full weight-bearing and full un-loading. Results: The mean age was 38.2 and mean Amputee Mobility Predictor score was 40. Mean vertical movement, horizontal movement, single limb prosthetic stance, mean femoral adduction in swing and stance, and median socket comfort score were not statistically different. Conclusion: The socket design did not significantly effect skeletal motion and socket comfort. All socket designs are suitable depending on the patient-centric preferences and prosthetist skill set. Clinical relevance The comfort of the standard of care transfemoral amputation socket has been widely reported as problematic. A comparison of alternative designs in a controlled clinical trial environment will assist the clinician in understanding the impact of design regarding skeletal motion and comfort. Users could benefit from alternatives applied in clinical practice.

Lower limb prosthetic interfaces

“…46 Sub-ischial sockets appear to be comparable to ICS in coronal plane stability and vertical movement, but with lower peak pressure at the proximal-medial brim during gait. 24,47,48 Greater socket comfort and a narrower base-ofsupport during gait were reported for the sub-ischial socket compared to ICS due to its lower proximal trim line. 24,47 A literature review of transfemoral socket suspension systems concluded that in addition to suspension enhancement, use of liners and inner flexible socket walls improves function, and comfort, and may reduce the rate of skin problems.…”

Transfemoral Socket Fabrication Method Using Direct Casting: Outcomes Regarding Patient Satisfaction With Device and Services

“…11 Most published studies focus on TF amputee gait, socket design, suspension and/or function of the components including less than 15 amputees. 8,[18][19][20] Kahle et al found that different socket designs may have an effect on gait speed and risk of falling. 8 Fatone et al, have described a new interface and the fabrication methods used to produce a TF socket, including outcomes from two cases.…”

“…21,22 Kahle et al, investigated the trimline level and compared outcomes between socket designs in 15 cases, although only in a clinical setting. 18 The socket designs in these studies are mainly grounded on the prosthetist's experience, with few measurable design parameters or description of how the design is intended to affect and interact with the user's residual limb during the gait cycle. 11 Various terms have been proposed to describe the way forces are transferred between the residuum and the socket, the biomechanical principles upon which these terms are based are ill-defined.…”

Development of Prototype Low-Cost QTSS™ Wearable Flexible More Enviro-Friendly Pressure, Shear, and Friction Sensors for Dynamic Prosthetic Fit Monitoring

“…Limb amputations cause serious physical disabilities worldwide and compromise peoples’ quality of life globally. In the USA alone, in 2005, there were an estimated 1.6 million persons living with limb loss in the United States, with 19% to 21% of those individuals living with a transfemoral (above knee) lower limb amputation [ 1 ]. These numbers could double by 2050 due to the increasing rates of vascular disease and diabetes [ 2 , 3 ].…”