Clinical trial NCT05041998: Quantitatively-informed Socket Design Process
Official title: Improving Physical Function and Patient-reported Outcomes Through a Quantitatively-informed Socket Design Process
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Artificial Limbs
Lead sponsor: University of Pittsburgh
Sponsor class: OTHER
Collaborators: name: United States Department of Defense
First posted: 2021-09-13
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Participants will perform study activities with nine different versions (including the original unmodified) of their prosthetic socket in a randomized sequence.
Primary purpose: TREATMENT

Brief summary: This study will investigate the effects of specific standardized modifications to trans-femoral prosthetic sockets in a randomized within-subject design. This is in preparation for a subsequently planned clinical trial to validate the findings by implementing them into a fitting method for individual sockets.

Detailed description: Background: Lower limb amputees experience chronic health challenges such as residual limb skin problems, low back pain, and osteoarthritis. These problems are exacerbated by high physical activity levels and by poor prosthetic socket fit. Prosthetists believe that limiting residual femur and skin motion will improve force coupling and thereby address these problems. However, there are no data demonstrating how changes in socket design affect residual femur and skin motion, and, by extension, lead to improved patient-reported outcomes.

Objective/Hypothesis: Goal of this research is to improve the current socket design optimization process that involves trial and error and relies heavily on the prosthetist's experience and intuition by using a quantitatively informed optimization process. The hypothesis is that modifiable in-socket mechanics, i.e. residual femur motion, skin strain, and pressure within the socket, are related to socket design and patient outcomes, and can be estimated using readily available clinical measurements.

Specific Aims: First aim is to identify the key characteristics of in-socket mechanics that are related to physical function and patient-reported comfort and function. The second aim is to identify readily available clinical measurements that are associated with the in-socket mechanical characteristics that are related to outcomes. The purpose of this aim is to correlate our laboratory findings from Aim 1 with more conventional modalities for clinical assessment.

Research Strategy: Preliminary data demonstrates the feasibility of the proposed research plan and will progress to a pilot clinical trial. The two aims will involve 30 transfemoral amputees. A highspeed biplane radiography system is used to image the residual limb while participants walk on a dual-belt instrumented treadmill both in their current socket and in sockets with purposely altered volume, brim height, cross-sectional geometry, and stiffness. Three-dimensional (3D) skin motion within the socket will be determined by tracking the motion of 40 to 50 small metal beads placed in a grid pattern on the skin of the residual limb before donning the socket. Residual femur motion within the socket will be determined with submillimeter accuracy using a validated tracking process that matches subject-specific bone models obtained from CT to the biplane radiographs. Discrete in-socket pressure will be recorded at four locations using pressure sensing pads. Readily available clinical measurements will be collected as well, including gait analysis, foot loading patterns, ground reaction forces, residual limb tissue stiffness, and hip range of motion hip strength. Each participant will complete clinical questionnaires to qualitatively evaluate comfort, fit, and overall satisfaction after wearing each socket. The different socket modifications are intended to affect the in-socket mechanics of the residual limb, physical function and patient-reported outcomes (Aim 1). These relationships will be assessed using a generalized linear model. Correlation between the research grade measurements and accessible clinical measures (Aim 2) will be evaluated using bivariate correlation analyses. The information gained in Aims 1 and 2 will be used to develop a quantitatively-informed socket optimization process, wherein the clinical measurements associated with in-socket mechanics will be used to inform socket design optimizations.

Eligibility criteria: Inclusion Criteria:

* Transfemoral prosthesis user
* 18-80 years of age
* Body weight less than 125 kg
* Able to walk unassisted on a treadmill

Exclusion Criteria:

* Pregnant females
* Clinically diagnosed osteoporosis
* Previous high exposure to radiation

Primary outcomes:
measure: Residual Femur motion
timeFrame: 1 second
measure: Skin strain
timeFrame: 1 second
measure: Socket pressure
timeFrame: 20 seconds
Secondary outcomes:
measure: Gait symmetry
timeFrame: 20 seconds
measure: Plantar pressure
timeFrame: 20 seconds
measure: Static displacement
timeFrame: 1 second
measure: Tissue Stiffness
timeFrame: 3 seconds
measure: Trunk lean
timeFrame: 20 seconds
measure: Hip flexion/extension
timeFrame: 20 seconds
measure: Hip strength
timeFrame: 20 seconds
measure: Hip Range of Motion
timeFrame: 20 seconds
Other outcomes:
Locations:
city: Pittsburgh
country: United States
facility: University of Pittsburgh
state: Pennsylvania
city: Pittsburgh
country: United States
facility: Delatorre Orthotics & Prosthetics
state: Pennsylvania
Study officials:
affiliation: University of Pittsburgh
name: William Anderst, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Anderst W, Fiedler G, Onishi K, McKernan G, Gale T, Paulus P. Within-subject effects of standardized prosthetic socket modifications on physical function and patient-reported outcomes. Trials. 2022 Apr 12;23(1):299. doi: 10.1186/s13063-022-06205-z.