Extension block pinning in subacute/late bony mallet finger injuries

Abstract

Objective: Mallet finger is inability to fully extend a finger due to the disruption of the extensor mechanism integrity at the distal interphalangeal (DIP) joint level. Cases with DIP joint subluxation, and avulsion fractures involving more than 30% of the DIP joint surface are candidates for surgery. Subacute/late cases have poor outcomes. Investigating the success of extension block pinning in subacute/late bony mallet finger cases is aimed. Methods: Patient demographics, the rate of DIP joint involvement in plain X-rays, subluxation status of DIP joint, the time between injury and operation, the duration of the operation, complications in post-operative follow-up, extensor lag and healing status of bone were reviewed. Patient outcomes and relation with operative delay and joint subluxation were analyzed. Results: Mean rate of DIP joint involvement of study group was 43.4 ± 6.12%. Half of the study group (n=7) had DIP joint subluxation. Mean time from injury to operation was 29.78±20.4 days. Six patients’ time from injury to operation was longer than 5 weeks. Study group had statistically significant improvement after surgery. Preoperative mean extensor lag was 15.71° ± 7.30° and postoperative mean extensor lag was 5.57° ± 8.89°(p5 weeks) and presence of subluxation did not alter the outcome (p=0.353 and p=0.149, respectively). Conclusion: Extension block pinning technique is a fast, easy-to-apply technique with minimal morbidity. Although it has more limited results in chronic cases, it can be used safely in the majority of cases requiring surgery.