Unlike jersey finger, most mallet fingers can be satisfactorily treated with splint only (Fig. 23.2b) (Okafor et al. 1997; Stern and Kastrup 1988). This is even applicable for patients with delayed presentation. A short mallet splint to keep the DIPJ in extension for 6–8 weeks is often advocated (Crawford 1984; Kinninmonth and Holburn 1986). Garberman et al. showed that satisfactory outcome can be achieved with splint in mallet fingers of an average of 53 days from injury (Garberman et al. 1994). In the presence of a fracture, a lateral radiograph of the affected finger, together with the splint, is needed to ensure that no joint subluxation is created post application of the splint. It is well known that they can subluxate up to 3 weeks, so repeat imaging is required (Crawford 1984).

Surgical treatment has previously been recommended for fractures which involve more than 30% of the articular surface and palmar subluxation of DIPJ (Hamas et al. 1978). Kirschner wires and screws may be used (Damron et al. 1993; Hofmeister et al. 2003; Tuttle et al. 2006). This can restore the articular surface and prevent secondary degenerative changes. Moreover, early mobilization of the joint and prevention of skin complications, created by splint, have been proposed (Nakamura and Nanjyo 1994). Nevertheless, despite the presence of a large articular fragment and even joint subluxation, studies have shown satisfactory results with splint alone (Okafor et al. 1997; Wehbe and Schneider 1984). If there is marked subluxation, we would often use the Ishiguro technique, which involves an extension block wire to hold the fragment and a longitudinal wire across the DIP joint (Ishiguro et al. 1997) (Fig. 23.2c). If it is a delayed presentation, then it may not be possible to reduce the fracture with this percutaneous technique, in which case we use an internal tension band suture technique (Bauze and Bain 1999) (Fig. 23.2d) or a small hooked plate protected by neutralization k-wire (Fig. 23.2e).

Both conservative and operative treatments for mallet finger have been associated with a high complication rates (Stern and Kastrup 1988; Wehbe and Schneider 1984). While the complications of conservative therapy are often transient like skin ulceration from the splint, the complications of surgical intervention are often more long term, e.g. joint incongruity, infection, nail deformity and implant failure. It is known that a residual extension lag of an average of 8⁰ is observed with the treatment of splint (Okafor et al. 1997). While this will not lead to any functional deficit, patient may regard this as a poor cosmetic outcome. Thus, we recommend reserving surgery for a specific group of patients who desire to have early mobilization and better cosmetic outcome.

Treatment for extensor tendon subluxation can be conservative in the acute stage, i.e. within 3 weeks from injury (Rayan and Murray 1994). After the reduction of the extensor tendon into its designated route with MCPJ in extension, splint is applied to block MCPJ from flexion while freeing PIPJ. Buddy splint may also be added. The splint is applied for 6–8 weeks. Catalano et al. (2006) reported 8 of 11 injuries had no pain and either minimal or no subluxation at an average of a 14-month follow-up, while Rayan and Murry (1994) reported 12 of 18 injuries had no pain and tendon subluxation at an average of a 13-month follow-up.

In the subacute group, it is possible to still repair the sagittal band, without the need for a full reconstruction. This does give a better insight into the pathoanatomy and the true clinical problem (Fig. 23.3b). The sagittal band requires to be surgically repaired to the central tendon (Fig. 23.3 c–f). Post-operatively it is placed into a splint to prevent MCP flexion, but allows active PIP motion for 6 weeks (Fig. 23.3g).

For chronic sagittal band injuries or failed conservative therapy, surgical treatment is indicated. Many different procedures including repair of the sagittal band (Kettelkamp et al. 1971) and tendon stabilization using grafts like juncturae tendinum (Wheeldon 1954) and local proximal- or distal-based partial extensor digitorum communis slips (Carroll et al. 1987; Watson et al. 1997) have been described. One author (MF) prefers to reconstruct the sagittal band with a distally based partial extensor digitorum to create the radial sling for tendon stabilization (Fig. 23.4a) (Carroll et al. 1987).