Intramedullary fixation with bioabsorbable and osteoconductive hydroxyapatite/poly-L-lactide threaded pin in digital replantation

Identifying Predictors of Radiographic Distal Phalangeal Nonunion After Fingertip Replantation

PURPOSE

This study aimed to estimate the risk factors for distal phalangeal nonunion in cases involving Kirchner wire fixation after successful fingertip replantation.

METHODS

This study retrospectively analyzed 116 digits of 111 patients, including 74 and 42 digits with replantation in Tamai zones I and II, respectively. Univariate and multivariable analyses were performed to assess the influences of 15 independent variables on nonunion, including age, sex, medical history of diabetes mellitus, history of smoking, injured hand and digit, injury type (clean, blunt, and crush-avulsion), amputation type (complete or incomplete), length of the distal bone fragment (mm), fracture type (simple or comminuted), presence of a bone defect, length of the fracture gap after fixation (mm), number of Kirchner wires used, evidence of venous repair, and the occurrence of pin tract infections after fixation.

RESULTS

At 12 months after replantation, 100 digits showed bony union and 16 (13.8%) digits showed radiographic nonunion or equivalent complications, including 9 digits with asymptomatic nonunion without a secondary operation, 5 that underwent an additional operation for nonunion or a complication, and 2 with distal bone resorption. A multivariable analysis indicated that the postfixation fracture gap was the only significant predictor influencing nonunion (odds ratio, 3.30; 95% confidence interval, 1.92-5.68).

CONCLUSIONS

The extent of the postfixation fracture gap had the greatest influence on preventing distal phalangeal nonunion, indicating the importance of reducing the fracture gap in primary fixation as much as possible.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.