Contribution of revision amputation vs replantation for certain digits to functional outcomes after traumatic digit amputations: A comparative study based on multicenter prospective cohort

Traumatic digit amputations can result in significant impairment. Optimal surgical treatment is unclear for certain digits in various amputation patterns. Our aim was to compare the contribution of revision amputation vs replantation for each particular digit to functional outcomes.Prospective cohort study at three tertiary hospitals was conducted in China. Eligible participants were 3192 patients with traumatic digit amputations enrolled from January 1, 2014, to January 1, 2018. The primary outcome was Michigan Hand Outcomes Questionnaire (MHQ) scores 2 years after initial surgery. Secondary outcome was score on the Disabilities of the Arm, Shoulder, and Hand (DASH).Of 3192 enrolled patients, 2890 completed the study. Main-effect linear regression showed that participants with replantation of thumb, index, long, and ring (proximal to the proximal interphalangeal [PIP] joint) fingers had significantly better MHQ scores compared to participants with the corresponding finger revision amputation. DASH results were comparable. Finger-finger interaction analyses conducted with multifactor dimensionality reduction (MDR) revealed that the small finger and ring finger had the smallest and greatest interactions with other fingers, respectively. After stratification by amputation level of thumb, index finger, or long finger, linear regression showed that replantation of the ring finger distal to the PIP joint resulted in better MHQ and DASH when the thumb or long finger was also traumatically amputated proximal to the IP/PIP joint.Replantation of the thumb, index, long, and ring (proximal to PIP joint) fingers is preferable to revision amputation, regardless of amputation pattern. Replantation of the ring finger amputated distal to PIP was beneficial only when the thumb or long finger was amputated proximal to IP/PIP joint. Replantation or revision amputation of the small finger was indistinguishable in terms of functional outcome. Future investigations and clinical decisions should take into account the role of finger-finger interactions.