Comparing low-cost monocentric and polycentric prosthetic knees: User satisfaction among persons with unilateral above- and through-knee amputations

Background: The International Committee of the Red Cross (ICRC) developed 2 low-cost prosthetic knees: monocentric (ICRC-MKJ) and polycentric (ICRC-PKJ), both intended solely for above-knee amputees. Independently, Imperial College London designed a low-cost polycentric knee (ICL-PKJ) for both above- and through-knee amputations. Because no affordable through-knee prostheses are currently available, clinics in low-to-middle-income countries often fit the ICRC-MKJ for through-knee amputees, although it is designed exclusively for above-knee amputees. Objectives: This study assesses user satisfaction with the ICRC-MKJ, ICRC-PKJ, and ICL-PKJ knees across individuals with unilateral transfemoral (UTF) and unilateral through-knee (UTK) amputations. Study Design: Single arm, repeated-measures design. Methods: 13 UTF (11 males, 2 females) and 5 UTK (males) consented to participate and trialed the 3 prosthetic knees. Each participant completed the Prosthesis Evaluation Questionnaire (PEQ) and Prosthesis Satisfaction Questionnaire (SAT-PRO) for each prosthesis. Results were compared. Results: For UTF participants, ICL-PKJ scored 39% lower than ICRC-PKJ ( p = 0.007) in PEQ Sounds. The Prosthesis Satisfaction Questionnaire perceived risk of harm score was higher with ICRC-MKJ (mean 33.3) than ICRC-PKJ (mean 53.9, p = 0.014) and ICL-PKJ (mean 69.2, p = 0.029). Aesthetics were rated higher for ICRC-MKJ (mean 87.2) than ICRC-PKJ (mean 66.7, p = 0.046) and ICL-PKJ (mean 69.2, p = 0.047). For UTK participants, PEQ Well-being increased by 37% with ICL-PKJ compared with their own ICRC-MKJ. Conclusions: The findings emphasize the need for prosthetic solutions that meet the mobility needs and social considerations of individuals with limb loss. These results underscore the urgent need to develop affordable, dedicated through-knee prostheses to provide effective options for through-knee amputees.