Role of magnetic resonance imaging in assessing factors affecting healing in scaphoid nonunions.

This study evaluates the role of magnetic resonance imaging in assessing the factors affecting the rate and healing time in scaphoid nonunions after surgery. Nineteen patients were assessed before surgery by radiographs, tomography, and magnetic resonance imaging. Fifteen had viable bone marrow and 4 patients had nonviable bone marrow on magnetic resonance imaging. All patients with normal preoperative magnetic resonance imaging healed in an average time of 4.7 months. Of the 4 patients with abnormal magnetic resonance imaging, but normal plain radiographs, 2 went on to heal in 10.5 months. The remaining 2 patients with abnormal magnetic resonance imaging and abnormal plain radiographs did not heal by 24 months. This study suggests 3 groups of scaphoid nonunions. Group 1 has normal trabecular bone radiographically and vascular bone marrow on magnetic resonance imaging and should be expected to heal after surgery. Group 2 has normal trabecular bone radiographically but avascular marrow on magnetic resonance imaging and may be expected to eventually heal after surgery. Group 3 has abnormal radiographs suggestive of fibrous replacement of the scaphoid proximal pole by the presence of cystic changes and the loss of trabecular bone, and avascular bone, as shown on magnetic resonance imaging. This study failed to show healing in this group of patients. Magnetic resonance imaging may be of benefit in predicting the healing potential in patients presenting with scaphoid nonunion.