A retrospective multidimensional comparison of microprocessor and mechanical knee users: Analysis of quality of life and satisfaction with the prosthesis.

Background: Despite the demonstrated greater efficacy of microprocessor knees (MPK) over mechanical knees (MK), the latter is still widely used by persons with transfemoral amputation. Besides motivations related to local insurance policies, quality of life (QoL) and satisfaction with the prosthesis play a key role in user preference.

Objective: The aim of this study is to compare QoL and satisfaction in a large sample of MPK and MK users and to assess how these outcomes are explained by clinical and demographic characteristics.

Study design: Retrospective study.

Methods: The study was conducted on 75 MPK and 60 MK users. Quality of life was assessed using the EuroQoL Five Dimensions and the EuroQoL Visual Analog Scale questionnaires. Satisfaction was assessed with the Satisfaction with Prosthesis questionnaire. All 3 instruments were self-administered. Univariate and multivariate regression analyses were conducted thereafter.

Results: The difference in satisfaction between MPK and MK users was not statistically significant. Significant differences were observed instead for QoL. From the univariate regression analysis, 6 factors were significant predictors of QoL and satisfaction. On multivariate analysis, the number of significant factors was reduced to 3, namely knee type, age at the first prosthesis, and experience with prosthesis. Type of knee and age at the first prosthesis significantly predicted QoL scores, explaining 12% of EuroQoL Five Dimensions and 25% of EuroQoL Visual Analog Scale variances. Age at the first prosthesis and experience with prosthesis predicted Satisfaction with Prosthesis scores in the multivariate model, explaining 25% of the variance.

Conclusions: MPK affects QoL but not satisfaction, which is positively driven by patients' experience with prosthesis and negatively affected by the age at the time of the first prosthesis.