Outcomes of conservative treatment for bony mallet fingers

The treatment strategy for bony mallet fingers remains controversial. The outcomes of conservative treatment were investigated in this study. In addition, the time to bone union, and gap between the bone fragment and distal phalanx are discussed.

The subjects were 26 patients (27 fingers) with bony mallet fingers (20 males and 6 females, mean age: 46.0 years old, the mean limitation of extension of the distal interphalangeal (DIP) joint: - 20.2°). In conservative treatment, splinting was applied for 6 weeks, followed by 2-week taping. The time to bone union, range of motion of the DIP joint, and the Crawford classification on the final follow-up were investigated. In addition, the bone fragment occupation rate was evaluated on plain radiography on the first examination. Furthermore, the gap on the first examination and after splinting. The relationship between the gap and bone union period was also investigated.

The mean time from injury to bone union was 170.2 days, the mean range of motion of the DIP joint was - 8.5° in extension and 60.9° in flexion, and the Crawford classification was Excellent for 22 fingers, Good for 2, Fair for 2, and Poor for 1. On the first examination, the mean bone fragment occupation rate was 44.0%. The mean gap on the first examination was 1.1 mm and this was significantly narrowed to 0.8 mm after splinting (p < 0.01). No significant correlation was noted between the time to bone union and gap on the first examination (p = 0.16), however, a significant positive correlation was noted between them after splinting (p < 0.01).

This study suggested that a favorable clinical outcome can be achieved by conservative treatment. Moreover, the bone union period decreased as the gap after splinting decreased, being significantly correlated.