SURGICAL TREATMENT OF MALLET FRACTURES BY EXTENSION BLOCK KIRSCHNER WIRE TECHNIQUE

Abstract

A rapid flexion or hyperextension force applied to an extended distal phalanx causes mallet finger, also referred to as "drop finger." This injury may or may not involve a distal phalanx avulsion fracture and affects the terminal extensor tendon. Usually closed, it is thought to be the most frequent hand tendon injury, especially in zone 1(1). An avulsion of the extensor tendon and a piece of bone from the distal phalanx are both involved in a bony mallet finger(1,2). Sports or work-related activities are common causes of these injuries (3,4). If the oblique retinacular ligament and related lumbrical tendon are not sufficiently relaxed, the full recovery of extension is restricted. Mallet finger can result in swan-neck deformity of the proximal interphalangeal (PIP) joint or osteoarthritis of the distal interphalangeal (DIP) joint if treatment is not received(5). Although the mechanism of the condition is well understood, there are disagreements over the most appropriate method of treatment, with some suggesting for open surgery with plates, minimally invasive techniques, and conservative splinting. There are differences in what constitutes a successful course of treatment; acceptable extension deficits range from less than 20° to less than 10°(2,6). A splint is usually used to immobilize the DIP joint in mild hyperextension for 8–12 weeks as part of conservative treatment. Nevertheless, even a small amount of movement during this time can impede the healing process, resulting in the formation of scar tissue and functional deficiencies(5,7). When more than one-third of the articular surface is affected or when the distal phalanx exhibits volar subluxation, surgery is frequently the preferred course of action(8,9). Risks associated with open surgical techniques include infection, nail deformity, and osteomyelitis(10). Ishiguro addressed these limitations in 1988 by introducing a minimally invasive technique using percutaneous Kirschner wires (K-wires) that allows for closed reduction, secure fixation, and early mobilization. Although the number of complications varies from study to study, the extension block K-wire technique has been acknowledged for its ease of use, low morbidity, and capacity to achieve satisfactory functional outcomes(10). In light of the disparity in the literature currently in publication, the purpose of this study is to evaluate the functional results of treating mallet fractures in a local population using the extension block K-wire technique. This will add to the body of evidence and guide clinical practice.