Clinical and radiological midterm outcome after treatment of pilonoidal fracture dislocations of the proximal interphalangeal joint with a parabolic dynamic external fixator.

Several methods treating proximal interphalangeal joint (PIP) fracture dislocations have been established providing early joint mobilization. The aim of this study was to evaluate the clinical and radiological outcome of unstable fracture dislocations of the PIP treated with a parabolic dynamic external fixator consisting of two Kirschner (K)-wires. Twenty-one patients who sustained a pilonoidal fracture of the PIP joint and were treated with a dynamic external fixator were evaluated retrospectively. The active range of motion, pain level, DASH score, Buck Gramcko Score, and the patient's satisfaction and acceptance were assessed. X-ray images were evaluated for bone healing, joint alignment, and signs of osteoarthritis. Mean PIP joint range of motion was 76°. Patients showed very mild discomfort (mean 0.7), high patient satisfaction (mean 1.9), and a moderate acceptance (mean 2.7). The mean DASH score was 11.6 and the Buck Gramcko score 13. All patients showed bone healing. One patient suffered from a recurrent dislocation, and another a subluxation of the PIP joint while wearing the fixator. Both joints could be corrected by modifying the fixator under image intensifier. Twenty patients (95%) showed a concentric and stable aligned joint. Three patients showed an osteoarthritis stage 0, five stage 1, nine stage 2, three stage 3, and one stage 4 according to the Kellgran-Lawrence Score. The use of a parabolic dynamic external fixator constructed from two K-wires restores joint alignment and stability in unstable pilonoidal PIP joint disclocation fractures. It allows immediate PIP joint mobilization to avoid adhesions. Modifications of the radius of the parabolic construct within cases of postoperative malalignment, without anesthesia, can restore joint axis and malalignment. This fixator is a cost-effective alternative, showing a good clinical outcome.