Carpal bone injury is uncommon in children. Similar to adults, the most common fracture involves the scaphoid. Bone scan is a well established method for diagnosing an occult carpal bone injury in adults, but there is insufficient data in the pediatric literature. The goal of this study was to assess the role and value of bone scan for a treatment of possible carpal injury.
This was a retrospective review to look at the sensitivity and specificity of bone scans. The algorithm for treatment of scaphoid fracture was based on the initial presentation. When a scaphoid fracture was suspected, a set of wrist radiographs with four standard views was performed. If this was found to be normal, a splint was applied and a clinic appointment made in 10-14 days. If the symptoms had resolved on the return visit and x-ray examination was normal, then the patient’s immobilization was discontinued. In contrast, if the symptoms and signs persisted, a second set of x-rays was obtained. If this was normal the patient was referred for a bone scan or immobilization was continued. After an additional two weeks, a bone scan was requested if radiographs and clinical findings were equivocal.
Based upon the criteria, 14 of the 64 patients were excluded from the study. This left 50 patients with an age range between 9-16 years. The difference between the first set of x-rays and subsequent bone scan averaged 11 days. Evidence of scaphoid fracture on the bone scan was found in eight patients. Two patients had distal radius fractures, one patient had a capitate fracture, and one had a trapezoid fracture. There were no complications related to the bone scan and the study was performed approximately three hours after tracer injection with a single static image of both hands. The bone scans and x-rays were concordant in 34 patients. In 31 of these patients, the bone scans and x-rays were normal. In 3 patients the second set of x-rays confirmed subtle fractures that correlated with the bone scan findings. There were 3 patients where the bone scans and x-rays were discordant. These patients had normal bone scans but x-rays suggested a possible fracture. There were 9 patients who had evidence of fractures on bone scan and had normal plain x-rays. Six of these patients involved the scaphoid, which would have been under treated without bone scan.
This articles supports that bone scan is a valuable tool for physicians when faced with a patient with persisted symptoms and equivocal x-ray findings. In children, the bone scan may even be more specific for fracture as compared to adults. Adults can have other problems that result in increased up take such as STT arthritis. Therefore the specificity of diagnosis of carpal fracture in the pediatric population using a bone scan is higher than in adults. In equivocal cases, bone scan may be beneficial to make the diagnosis and limit the immobilization time. However, the role of MRI is quickly emerging and may surpass bone scan in the future. MRI is currently the test of choice to rule out occult scaphoid fracture in adults. Most likely, this will ultimately be true for the pediatric and adolescent population as well.