Performance of a Sensor to Monitor Socket Fit: Comparison With Practitioner Clinical Assessment

Introduction: A sensor that detects changes in prosthetic socket fit before they manifest clinically may be helpful towards rehabilitation after limb amputation. Materials and Methods: Participants with transtibial amputation walked on a treadmill wearing amotor-driven, cabled-panel adjustable socket. Socket volume was slowly adjusted away from the neutral socket volume (panels flush). The percent socket volume change at which the practitioner, using visual assessment, first noted fit issues was compared with the percent socket volume change at which the sensor first detected a measurable change in fit. Results: Themedian percent socket volume change at which the sensor first detected a measurable socket enlargement (0.50%) was significantly less than both the median percent socket volume change at which the research practitioner first noted a change in fit (1.69%) (P = 0.008) and the median percent socket volume change at which the participant would normally add a sock (2.30%) (P = 0.005). During socket reduction, the practitioner noted a change in fit before the participant would normally remove a sock in only 2 of 10 participants. The median percent socket volume change at which the sensor first detected a measurable socket reduction (-0.44%) was significantly smaller in absolute value than the median percent socket volume change at which the participant would normally remove a sock (-2.76%) (P = 0.005). Conclusions: The sensor detected controlled socket fit changes before the research practitioner in this study. A next step will be to determine if the sensor detects unforced socket fit changes, and changes in user free-living environments.