SCAPHOID BONE BRUISE – PROBABLY NOT THE PRECURSOR OF ASYMPTOMATIC NONUNION OF THE SCAPHOID.

Abstract

Magnetic Resonance Imaging (MRI) is gaining popularity for the evaluation of acute wrist injuries, but findings may be confusing with uncertain clinical significance. The presence of bone marrow oedema but no fracture following trauma has been described in the knee and referred to as a bone bruise. The clinical implications of similar findings in the scaphoid have not been described.

This study aims to describe the clinical and radiological findings of an acute wrist injury known as the scaphoid bone bruise. An MRI classification is proposed, and the outcome described.

Between April 2000 and October 2004 all patients who underwent MRI scanning following an acute injury for suspected scaphoid fracture were considered for this study. The scaphoid bone bruise was treated with a degree of caution and the injured limb placed in a below elbow cast for six weeks. Review was arranged at three months when, if symptomatic, a further MRI was performed. A descriptive grading system depending on the extent of the bone bruise was developed.

41 patients were included in the study. At three months 26 were asymptomatic. Seven defaulted from follow-up. Eight patients were still symptomatic and underwent further MRI scan. The bone bruise was classified into four grades according to the degree of oedema found on MRI. Seven patients were grade 1, 18 patients were grade 2, 11 grade 3, and the remaining five grade 4. Of the eight patients who underwent repeat MRI scanning all showed improvement of the bone bruise. At six months only 2 patients remained symptomatic.

While healing around the knee is seldom a problem, the possibility that scaphoid bone bruise may be a precursor to scaphoid non-union needs to be excluded. This study suggests that scaphoid bone bruise is a benign injury with predictable recovery over time and is unlikely to result in long-term morbidity in the form of non-union. It may be feasible to mobilise these injuries much sooner. However, further study with longer follow-up and repeat MRI scans is necessary to be confident that caution about these injuries is unnecessary.