The missing link: How is the phantom limb influenced by prosthesis wearing in people with lower-limb amputation?

Background: Recent therapeutic and technological solutions aim to improve the daily living of people with limb amputation by considering various aspects of the phantom limb, in particular painless phantom sensations (PS) and voluntary phantom movements (VPM).

Objective: Although previous research has explored these phenomena mostly without considering the prosthesis, this study investigates the influence of prosthesis wearing on painless PS, painful PS, and VPM, in people with lower-limb amputation.

Study design: Cross-sectional study based on semi-directed interviews.

Methods: Semi-directed interviews were conducted with 111 people with major lower-limb amputations. They described their phantom limb without and with the prosthesis, in a static seated position. The influence of the prosthesis wearing on the intensity of painless PS, painful PS, and on VPM ability was classified into 5 categories: disappearance, decrease, modification, increase, and appearance.

Results: Prosthesis wearing leads mostly to an increase of painless PS intensity (44%), a decrease of painful PS intensity (44%), and an improvement of VPM ability (47%). The study also highlights the richness of prosthesis-related changes, including modifications in phantom limb position, shape, and size. The influence of prosthesis wearing on phantom phenomena was not related to the presence of referred sensations, the amputation etiology, the level of amputation, the time since amputation, or the use of medication, but might be related to the pressure applied by the socket on the residual limb.

Conclusions: This study provides valuable information on the influence of the prosthesis on PS and may allow for better consideration of this relationship in the context of research, engineering, and rehabilitation.