Journal article
Performance of conventional and X2® prosthetic knees during slope descent
Clinical biomechanics (Bristol), Vol.33, pp.26-31
03/2016
DOI: 10.1016/j.clinbiomech.2016.01.008
PMID: 26921583
Abstract
Background: Individuals with transfemoral amputation often have difficulty descending sloped surfaces due to increased lower extremity range of motion and torque requirements. The X2®, a new microprocessor-controlled prosthetic knee, claims to improve gait over sloped terrain. The aim of this study was to evaluate how experienced prosthesis users descended a sloped surface using the X2®, compared to a conventional knee, either mechanical (MECH) or microprocessor (MP).
Methods: Descent technique and biomechanics were assessed in 21 service members with unilateral transfemoral amputation as they descended an instrumented 10° slope at a self-selected walking velocity.
Findings: Use of the X2® in the MECH group resulted in greater hill assessment scores (8.5 to 11.0, P=0.026), due primarily to decreased reliance on handrail use. The use of the X2® in the MP group increased prosthetic knee flexion to a median of 6.4° at initial contact (P=0.002) and 73.7° in swing (P=0.005), contributing to longer prosthetic limb steps (P=0.024) and increased self-selected velocity (P=0.041). Additionally, the use of the X2® in the MP group increased prosthetic limb impact peaks (11.6N/kg, P=0.004), improving impact peak symmetry to −1.3% (P=0.004).
Interpretation: Decreased reliance on handrail use as MECH users descended in the X2® indicate improved function and perhaps greater confidence in the device. Additional biomechanical improvements for existing MP users suggest potential longer-term benefits with regard to intact limb health and overuse injuries.
•Descending sloped surfaces is difficult for individuals with transfemoral amputation.•Advanced microprocessor knees may improve functional outcomes in slope descent.•Compared to mechanical knees, the X2® promoted an independent descent technique.•Compared to microprocessor knees, the X2® increased knee flexion at contact and swing.•Compared to microprocessor knees, the X2® increased between-limb symmetry at impact.
Details
- Title: Subtitle
- Performance of conventional and X2® prosthetic knees during slope descent
- Creators
- Elizabeth M Bell - Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD 20889, USAAlison L Pruziner - Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD 20889, USAJason M Wilken - Center for the Intrepid, San Antonio Military Medical Center, JBSA Fort Sam Houston, San Antonio, TX 78234, USAErik J Wolf - Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD 20889, USA
- Resource Type
- Journal article
- Publication Details
- Clinical biomechanics (Bristol), Vol.33, pp.26-31
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.clinbiomech.2016.01.008
- PMID
- 26921583
- ISSN
- 0268-0033
- eISSN
- 1879-1271
- Language
- English
- Date published
- 03/2016
- Academic Unit
- Physical Therapy and Rehabilitation Science
- Record Identifier
- 9984047692602771
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