The relationship between in-socket mechanics and patient-reported comfort and function, a randomized crossover trial

Lower limb loss presents significant challenges, resulting in chronic health issues and impacting the quality of life. Prosthetic socket design is crucial for optimizing comfort and function in individuals with limb loss. This study aimed to determine the relationship between in-socket mechanics and patient-reported comfort and function, hypothesizing that residual femur motion, skin strain, and pressure distribution correlate with these outcomes. Ten individuals with transfemoral limb loss participated, with modifications made to personalized prosthetic check sockets to assess these variables, and data from eight subjects were included in the analysis. Data collection included CT scans, dynamic biplane radiography, in-socket pressure measurements, plantar pressure assessments, ground reaction force analyses, conventional motion capture assessments, and patient-reported outcomes. Generalized estimated equations were used to examine the relationships between peak skin strain during gait and patient reported outcomes and correlation matrices were constructed to explore relationships between static imaging, skin strain, residual bone motion, and gait kinematics. Our findings indicate that the combination of skin strain metrics significantly predicts variability in comfort, while the overall model was not significant with respect to function. Significant correlations were also observed between static imaging and dynamic residual bone motion. These results suggest that minimizing and monitoring skin strain, particularly in the anterior central socket region, can enhance prosthetic fit and patient satisfaction. Additionally, static imaging under different loads effectively predicts dynamic displacements, offering a less invasive method for clinical assessments. These insights highlight the need for integrating objective in-socket measurements into clinical practice to improve prosthetic socket fitting, ultimately enhancing the quality of life for individuals with lower limb loss. ClinicalTrials.gov NCT05041998. Date of registration: March 9, 2021.