A comparative evaluation of oxygen consumption and gait pattern in amputees using Intelligent Prostheses and conventionally damped knee swing-phase control

Objective: To compare the gait of amputees wearing conventionally damped pneumatic swing-phase control knees and microchip-controlled Intelligent Prostheses. Design: Crossover trial. Setting: An amputee rehabilitation centre in a teaching hospital. Participants: Ten established unilateral transfemoral prosthetic users were asked to participate in the trial, all agreed. Interventions: The amputees were assessed wearing pneumatic swing-phase control knees and then with the Intelligent Prosthesis. Main outcome measures: Oxygen consumption while walking at different speeds on a treadmill, video-recording of gait assessed by a panel and temporal-spatial parameters of gait whilst walking at slow, fast or normal speeds in a gait laboratory. Results: Mean oxygen cost for all subjects at 0.69 m/s was 0.33 ml/kg.m with the conventional limb and 0.30 ml/kg.m with the Intelligent Prosthesis (p = 0.01). At 1.25 m/s the mean oxygen cost for the conventional limb was 0.24 ml/kg.m and for the Intelligent Prosthesis was 0.22 ml/kg.m (not significant). The ANOVA analysis showed that oxygen cost was similar at normal walking speeds but increased more at lower speeds for the pneumatic swing-phase control leg compared to the Intelligent Prosthesis (p < 0.02). There were no significant differences in subjective gait evaluation or temporal and spatial gait parameters. Conclusion: At lower speeds oxygen cost was lower with the Intelligent Prosthesis. Gait analysis detected no significant changes between the two legs.