Comparison of Orthosis Management Failure Rates for Mallet Injuries

PURPOSE: A closed mallet injury is a common finger injury involving terminal extensor tendon avulsion from its insertion on the distal phalanx. Nonsurgical treatment with continuous extension orthosis fabrication is the preferred treatment. Our purpose was to report the failure rates of orthotic management by digit and investigate other factors that contribute to failure. METHODS: This was a retrospective chart review of all patients with an isolated mallet finger injury managed at our institution from 2011 to 2019. Patient demographics, details of management, and treatment outcomes were collected. Failure rates were compared for all digits, specifically comparing the little finger versus all other digits. A categorical variable analysis was performed to identify risk factors for failure of orthosis management. RESULTS: Out of 1,331 identified patients, 328 met the inclusion criteria. There was no statistically significant difference of failure rate between digits. There was a trend toward the little finger failing at a higher rate (n = 131, 40%) than the other digits individually (P = .08) and combined (n = 95, 29%; P = .06). An older age at injury was associated with failure. The median patient age with failure was 54 years, versus the median patient age with nonfailure of 48 years (P < .01). The failure rate was higher in tendinous versus bony mallet injuries (n = 131, 40% vs n = 66, 20%, respectively; P < .01). The orthotic type was associated with the failure rate, and failure was highest in patients treated with Stack orthoses (n = 183, 56%; P = .01). CONCLUSIONS: There was no significant difference in the orthotic management failure rate by digit for a mallet injury. Statistically significant risk factors for failure are increasing age, a tendinous injury, and the orthotic type. Further evaluation with a larger cohort is warranted to increase the statistical power of the findings. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.