The Effect of Alignment on the Balance and Confidence of Trans-Femoral Prosthesis Users

This pilot study aims to assess the effect of prosthetic alignment on the balance and confidence of trans-femoral prosthesis users.
The prosthetic alignment of five non-vascular trans-femoral prosthesis users were recorded using a bench alignment apparatus. The hip range of motion of each participant was assessed using the Thomas Test to establish the recommended socket flexion angle for bench alignment and compared to the socket flexion in the original prosthesis alignment.
The Activities-specific Balance and Confidence Scale (ABC) was used to determine user baseline balance and confidence with the original prosthetic alignment.
Each prosthesis was then re- aligned using two pre-determined angles of initial socket flexion. Dynamic alignment was conducted without adjustment to socket flexion or extension above the knee joint and the effect of compensatory adjustments noted. The resulting dynamic alignment of each configuration was compared using the bench alignment apparatus.
Each participant was assessed using the L-Test and Four Step Square Test (FSST) in the each of the alignment configurations of their everyday prosthesis.
Results showed a high level of balance confidence (Mean ABC = 86.6, s.d. = 8.1), walking ability (L-Test mean = 24.77 seconds) and balance (FSST mean = 12.43 seconds) in all alignment configurations. No statistically significant differences were found in the times recorded for the L-Tests and FSST, for any participant, in any alignment configuration. The results indicate healthy, active prosthesis users can adapt using compensatory movements to accommodate changes in prosthetic alignment. The clinical significance of these compensatory movements requires further investigation.
Future research to promote understanding of the influence of prosthetic alignment and the effects of compensatory movements on balance and confidence in a lower limb absent population is required. Such work is important to facilitate long-term optimal functional ability of the prosthesis user.