The use of pressure sensors for the improvement of limbsocket interface in lower limb amputation : A pilot study
Résumé
30-100% of people with lower limb amputation have reported problems causing discomfort or residual-limb complications altering their ability to walk. Appropriate fit of the prosthetic may be considered the most important parameter in the success of a lower-limb prosthesis, and poor fit can result in undesirable pressure distribution at the residual-limb/socket interface and consequently cause discomfort, pain, and potential tissue breakdown. In order to obtain appropriate fitting, orthoprosthetists estimate the inclination of the socket on the antero-posterior and medio-lateral axes as well as the inclination of the prosthetic according to the ground. This is a very complex process and no quantitative data exists to help clinicians in their practice. The aim of this project is to provide the clinician with parameters to help individualize the settings of the prosthetic in terms of alignment and functional use. Biomechanic measures were performed during standing and walking using 9 small pressure sensors in the limb-socket interface. The patients were further asked for subjective felt pressure. So far, 7 subjects (6 male, 1 female, 6 transtibial, 1 transfemoral) has been tested. Results are presented as pressure (kPa) over time during one stride. Preliminary findings illustrate how to potentially use this equipment in the clinic, combining pressure data and basic knowledge of biomechanics and physiology of the stump for each subject. For example, one patient illustrated alarmingly high pressure at the distal end of tibia during mid-stance. The patient himself did not however report any extensive pressure at this area. The pressure sensors thus inform the orthoprosthetists to adjust the prosthetic, potentially avoiding unnecessary tissue break-down and negative long-term effects from compensatory strategies. The use of pressure sensors during the initial setting of the prosthetic seems beneficial for both the clinicians and patients. Further work should consider collecting data before and after making adjustments to the prosthetic, to further illustrate the importance of a correct fitting