Clinical and System-Level Factors Associated With Digital Replantation Following Complete Traumatic Thumb or Other-Finger Amputation: A National Inpatient Analysis, 2016-2021.

Purpose: Digital replantation is traditionally guided by injury mechanism, functional priority, ischemia time, and patient factors. Pediatric age is commonly considered a favorable indication, whereas advanced age is often assumed to reduce candidacy. We examined associations of age and area-level zone improvement plan (ZIP) -income quartile with digital replantation following complete traumatic thumb or other-finger amputation. Methods: The National Inpatient Sample was queried from 2016 to 2021 for hospitalizations with complete traumatic upper-extremity amputations, including thumb, other-finger, wrist-region, and hand amputation. The primary analytic cohort was limited to complete thumb and other-finger amputations; wrist and hand amputations were retained only for descriptive context. The primary outcome was digital replantation during the included hospitalization, identified using prespecified International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) and Procedure Coding System (ICD-10-PCS) Reattachment procedure codes. Analyses used survey-weighted multivariable logistic regression to account for National Inpatient Sample discharge weights, strata, and hospital clusters. The model adjusted for patient demographics (age group, sex, race, payer, ZIP-income quartile), injury-related factors (digit group and additional injury diagnosis), and system-level characteristics (transfer-in status, hospital size, teaching status, region, weekend admission, and year). Results: The primary digital cohort included 1,458 unweighted hospitalizations, representing 7,290 weighted hospitalizations nationally. Digital replantation was coded in 361 unweighted hospitalizations (weighted n = 1,805; 24.8%). In the adjusted model, higher area-level ZIP-income quartile was associated with digital replantation: compared with quartile 1, adjusted odds ratios (aORs) were 1.52 for quartile 2 (95% CI, 1.06-2.18), 1.83 for quartile 3 (95% CI, 1.24-2.70), and 2.23 for quartile 4 (95% CI, 1.44-3.44). Transfer-in status (aOR, 1.98; 95% CI, 1.49-2.62) and thumb amputation (aOR, 2.15; 95% CI, 1.64-2.81) were also associated with digital replantation. In contrast, no age category was statistically associated with digital replantation after adjustment. Children aged 0-12 years had an aOR of 0.96 (95% CI, 0.53-1.74), adolescents aged 13-17 years had an aOR of 0.84 (95% CI, 0.40-1.75), and adults aged 65 years or older had an aOR of 0.64 (95% CI, 0.32-1.27). Conclusions: Among included hospitalizations, higher area-level ZIP-income quartile, transfer-in status, and thumb involvement were associated with digital replantation after adjustment for measured covariates. No age category was statistically associated with digital replantation after adjustment. These findings suggest that patterns of digital replantation may reflect not only anatomic factors but also area-level socioeconomic context and referral-related characteristics. Because the database lacked detailed information on injury mechanism, technical candidacy, comorbidity, and geographic access, these associations cannot distinguish differences in replantation candidacy from differences in referral access or treatment selection. Type of study/level of evidence: Prognostic III.