Extension pin block technique versus extension orthosis for acute bony mallet finger; a retrospective comparison

Abstract

Purpose: This study aimed to compare the clinical, radiological, aesthetic and economic outcomes of extension pin block technique and extension orthosis in closed mallet fractures with more than 1/3 of articular surface involvement without subluxation (Wehbe and Schneider classification type IB and IC).

Materials and methods: Thirty-nine patients (11 women and 28 men; mean age: 40.9±11.5 years) who had mallet fractures were retrospectively reviewed. Twenty-one patients were treated with the extension pin block technique, and the remaining 18 were treated with the extension orthosis. Fracture classification, measurement of articular surface involvement, presence of subluxation, and the fragment displacement were performed according to the Wehbe and Schneider classification. Crawford's criteria, extension lag, distal interphalangeal joint (DIPJ) range of motion, dorsal bump, and visual analog scale were evaluated. Fracture union, articular incongruity, and all other complications were followed and analyzed. The Michigan Hand Questionnaire (MHQ) was used to evaluate the aesthetic perception of the patient's finger. Direct and indirect costs were calculated for each treatment method.

Results: At the final follow-up (mean: 18.4±6.2 months), there was no significant difference with respect to clinical outcomes between groups (p=0.335) and pain (p=0.131). Fracture union was achieved in all cases. Both extension lag (p=0.150) and DIPJ flexion (p=0.261) were not different between groups. Dorsal bump was more frequent in the conservative treatment group (p=0.048). Aesthetic scores were similar between groups (p=0.477), but female patients rated significantly lower aesthetic scores than males (p=0.003) regardless of the treatment method. The direct medical (p=0.001), indirect (p=0.009) and cumulative costs (p=0.001) were significantly higher in surgical treatment group. One pin tract infection, one nail dystrophy, and one joint space narrowing were seen in the surgical treatment group versus none in the conservative treatment group (p=0.698).

Conclusions: Conservative treatment does not result in inferior clinical, radiographic and aesthetic outcomes compared to surgical fixation in closed mallet fractures with more than 1/3 of articular surface involvement without subluxation. Extension orthosis which is non-invasive, and cheap, maybe the treatment of choice in closed mallet fractures.

Level of evidence: IV; Retrospective cohort.

Keywords: Bony mallet; Conservative treatment; Extension pin block; Extension splinting; Mallet finger.