A Functional Angle of Up to 35° at the Distal Interphalangeal Joint Can Be Achieved with Headless Compression Screw Fusion.

Abstract

Arthrodesis of the distal interphalangeal (DIP) joint reliably improves symptomatic arthritis. A range of successful surgical techniques including tension band wiring, plate fixation and headless compression screws have been described and produce stable painless unions. For best functional outcome, the fusion angle should be between 10 and 61 degrees. In the past, it has been difficult to achieve more than 10 degrees of flexion with a headless compression screw. Higher fusion angles have been reported using tension band wiring techniques. However, metalwork prominence is a common problem and may require revision surgery to rectify this. Headless compression screws are reported to cause iatrogenic fractures due to the size of the screw relative to the small diameter of the phalanx. This case series achieves an angle of up to 35 degrees with a good functional outcome. Open fusion of the DIP joint with a headless cannulated compression screw, of 2.2 mm in diameter, was undertaken in fifteen digits. Patients received standard departmental follow up to radiographic union. Patients self-reported function using the Michigan Hand Questionnaire post operatively. The fusion angles achieved were assessed on postoperative radiographs. All patients went on to a stable union without any patients requiring revision surgery as a result of fracture or protrusion of metalwork. Complications were observed in two patients which included one superficial infection (n = 1) and a discomfort requiring removal of metalwork (n = 1). Functional scores measured post operatively showed favourable outcomes. In this series, successful fusions of the DIP joints, at an angle up to 35 degrees were achieved using small diameter headless compression screws, which provided benefits including early mobilization and favourable functional outcome scores.