Carpal instability, the missed diagnosis in patients with clinically suspected scaphoid fracture.

To determine the incidence of carpal instability and its relation to clinical findings in patients with suspected scaphoid fracture, we performed a long-term follow-up investigation in a consecutive series of 160 patients who were treated in our department of traumatology for suspected scaphoid fracture after a fall on the outstretched hand. Radiography of the carpus was obtained. Bone scintigraphy was performed in all patients with negative initial radiographs. Follow-up investigation was performed in 100 patients and consisted of history, clinical examination, including measurement of grip strength and wrist movement, synovia stress test, Watson's scaphoid test, and radiographic examination. In 22 patients, clinical or radiological signs of carpal instability were found. The incidence of complaints and a positive synovia test were significantly higher in patients with suspected carpal instability. The bone scan was not useful for the detection or exclusion of carpal instability. The three-phase bone scan gave no additional information in the diagnosis of carpal instability.