Factors Related to Failure of Conservative Treatment in Volar Plate Avulsion Fractures of the Proximal Interphalangeal Joint

Background: Volar plate avulsion fractures of the proximal interphalangeal (PIP) joint are a common hand injury and have been treated conservatively with favorable results. We assumed that conservative treatment of volar plate avulsion fractures of the PIP joint would be unsuccessful if the fracture fragment, even if small, was much displaced or rotated and that delayed excision of the avulsion fractures would result in good outcomes. We report clinical and radiological outcomes of conservative treatment of volar plate avulsion fractures of the PIP joint and risk factors for failure of conservative treatment. Methods: We retrospectively reviewed the clinical and radiological outcomes of 88 volar plate avulsion fractures (85 patients) treated conservatively at first. In 18 of these fractures, delayed excision of the fracture fragment was required after an average of 75 days of conservative treatment for limited motion or pain of the joint. We compared parameters between failed cases and successful cases after conservative treatment. Results: Compared to the successful cases, the failed cases had a higher prevalence of joint dislocation at the time of injury and greater pain, larger flexion contracture, and less further flexion after conservative treatment. The shape, comminution, and size of the fracture fragments were not related with the need for operation, but the operative cases had greater displacement and rotation of the fracture fragments than the conservative cases. After fragment excision, postoperative protection of the joint was not necessary, pain was reduced, and the mean range of motion increased. Conclusions: The presence of joint dislocation and greater displacement and rotation of the fragments may be associated with the failure of conservative treatment of volar plate avulsion fractures. Failed cases after conservative treatment could be resolved by delayed fragment excision with favorable results. Therefore, it might be appropriate to consider conservative treatment at first in almost all volar plate avulsion fractures of stable PIP joints.