Background: The standard surgical approach to amputation has failed to evolve significantly over the past century. Consequently, standard amputations often fall short with regards to improving the quality-of-life (QoL) for patients. A modified amputation has been designed at both the transtibial (TTA) and transfemoral (TFA) level that incorporates agonist-antagonist myoneural interface (AMI) constructs to provide patients with a novel alternative to standard amputation. Here, we present the patient reported outcome measures (PROMs) amongst our lower extremity AMI amputees and demonstrate an overall significant improvement in their physical and mental wellbeing.
Methods: Four PROMs surveys, 1) EQ-5D-3L, 2) Lower Extremity Functional Scale (LEFS), 3) PROMIS-57, 4) Short Form-36 (SF-36), and 5) Sickness Impact Profile (SIP), were administered to lower extremity AMI amputees pre-operatively (baseline) and at 6 weeks, 3 months, 6 months, 9 months, 12 months, 24 months, 36 months, and 48 months post-operatively between June 24th, 2018, and December 15th, 2022. The surveys were either administered during a clinic visit or emailed at the encounter timepoint. Study data was collected and managed using REDCap (Research Electronic Data Capture) electronic data capture tools hosted at Brigham and Women’s Hospital. Analyses of collated data were performed by fitting a linear mixed model using SAS version 9.4 (SAS Institute, Cary, NC).
Results: The cohort’s baseline and 12-month post-operative responses were compared to determine score improvement. The cohort demonstrated a significantly improved EQ-5D-3L index value (p<0.0001) and EQ VAS (p<0.0001) at 12-months post-operatively (n=22) when compared to baseline (n=28). The LEFS score significantly improved at 12-months post-operatively compared to baseline (p<0.0001) with a mean of 59.04 ± 3.14 (SE) at 12-months and a mean of 31.96 ± 2.84 (SE) at baseline. AMI patients demonstrated significantly improved scores across PROMIS-57 domains at 12-months compared to baseline scores; the p-value was <0.0001 for all domains except for the Depression domain where p=0.0181. The health domain scores significantly improved from baseline to 12-months post-operation for all SF-36 domains. Lastly, the SIP indicated a significant decrease in overall dysfunction from baseline to 12-months post-operation (p<0.0001).
Conclusions: Modified lower extremity amputation with AMI construction has the potential to provide amputees with increased quality-of-life when compared to the pre-operative state. However, further investigation is necessary to determine whether the patient reported outcome measures of the AMI amputee cohort are superior to those who receive a standard amputation.