Building a Better Socket: UW Partners with Ability to Test New Diagnostic Tool
The prosthetic socket is the foundation of nearly all prosthetic solutions. In addition to improving patient compliance with wearing the prosthesis, a comfortable, properly fitted prosthetic socket helps to reduce skin breakdown, sores, and blisters, and increases safety during walking. Unfortunately, the fit of even the most carefully designed socket can be impacted by natural fluctuations in a patient’s residual-limb volume. Indeed, one of the most common complications prosthesis users face is pain from improper socket fit due to residual-limb volume fluctuations.
“A reduction in volume can cause the prosthesis to become loose on the residual limb while the person walks or runs, which can cause the user to become unstable or fall down,” says Kate Allyn, CPO/L, FAAOP, a research prosthetist at the University of Washington (UW) in Seattle. “An increase in volume restricts blood flow to the limb and makes the socket feel tight and painful, possibly leading to tissue injury.”
While prosthetists know that many individuals with limb loss experience residual limb volume changes throughout the day, predicting exactly how much and when those fluctuations will occur remain an inexact science.
“As prosthetists, we do our best to inspect the residual limb and evaluate the patient’s medical conditions to predict potential volume fluctuations, but without a tool to measure how a residual limb volume fluctuates, our assessment is an educated guess at best,” says Brian Kaluf, BSE, CP, clinical outcomes and research director at Ability Prosthetics & Orthotics.
UW engineers aim to reduce this guesswork and the complications associated with a poorly fitting socket. They have developed a device that measures in real time the percent increase or decrease of fluid volume in a patient’s limb by receiving data from small electrodes placed in different spots on the leg. The data is recorded to a circuit board, which is then transmitted wirelessly to a computer
The University has partnered with Ability P&O to evaluate different volume management solutions and test the new diagnostic tool. The research could make prosthetic limbs more comfortable for individuals with limb loss.
“The results of these studies will provide us with valuable information about what clinical interventions work best and which prosthesis users are likely to benefit from each,” says Allyn, the lead research prosthetist on the UW team.
Julie McCulley, MSPO, ATC/L, resident prosthetist/orthotist at Ability in Exton, Pennsylvania, is excited by the potential benefits to patients and prosthetists alike. “Patients will be able to understand their bodies better and how their limb volume is affected during different activities, times of day, and at various temperatures. Understanding each patient’s limb fluctuation will help us to more accurately guide and train patients in their care and select the proper componentry.”
Measuring residual limb fluid volume may also help prosthetist better communicate with referring physicians and aid with justification to insurance companies, Allyn adds.
“This sensor technology could provide a great advantage to a prosthetist when designing and fitting a prosthetic socket,” Kaluf notes. “We’re looking forward to potentially using this sensor technology to improve prosthetic socket fit and comfort for our patients.”
“Ability P&O was the perfect partner in this diagnostic tool presentation because they have multiple offices, an innovative, professional staff, and a sincere interest in research efforts,” Allyn says.