Early active mobilisation of volar plate avulsion fractures

Abstract

This is a prospective follow up of 190 consecutive cases of volar plate avulsion fractures. A standard management regimen of immediate, active movement was followed in all cases and physiotherapy was rarely required. Of the 190 patients, 162 were followed up for at least one year. An excellent or good outcome was achieved in 98 per cent. Patients presenting more than three weeks from injury had a worse outcome. The size and displacement of the avulsed fragment did not affect the outcome. For the stable joint, early active mobilisation with minimal or no splintage provides a good result.

Introduction

Volar plate injuries are an example of the ‘unseen’ forces which underly many hand injuries. An understanding of the soft tissue anatomy is important as these injuries do not look spectacular on radiographs. The functioning anatomy of the volar plate–collateral ligament complex and attachments at the interphalangeal joints was very well described in Bower's anatomical and biomechanical study of the proximal interphalangeal joint volar plate[1]. The volar plate avulsion fracture injury is usually caused by a hyperextension force, although a crush injury occasionally causes it. A volar or dorsal dislocation of the joint can also cause volar plate fractures[2]. In Eaton's classification of proximal interphalangeal joint injuries, the volar plate avulsion fracture is a type 1 injury and occurs when the middle phalanx is hyperextended up to 70–80 degrees at the time of injury. A longitudinal tear in the accessory collateral ligament can occur at the same time[3]. The bony avulsion nearly always occurs at the distal attachment[4], due to its fibrocartilaginous fusion with bone[5]. The proximal attachments of the volar plate (check reins) are strong and rarely torn. However, with slowly increasing volar forces, rupture of the proximal attachment occurs in cadaver models[1]. Diagnosis is based on the history of the mechanism of injury and clinical finding of a painful and swollen joint which is tender anteriorly. Passive flexion of the proximal interphalangeal joint produces anterior joint pain. This ‘volar plate test’ has been described to detect an ununited volar fracture which can remain symptomatic for many years[6]. A lateral radiograph usually reveals the avulsion fragment, although an oblique view is often required and should be done routinely. Rarely do these fractures show up on a posteroanterior view[4]and as a result the diagnosis may be missed. The proportion of volar plate ruptures which do not involve an avulsion fracture is difficult to estimate from the literature.

The recommended treatment varies widely. Late complications of this injury are flexion contracture, recurrent subluxations, swan-neck deformity and traumatic arthritis.