抄録
A 57-year-old male machine operator gradually developed a motion pain in the left elbow about 6 years ago without any known causes, which got worse with time. On his first visit to our clinic, active ROM was full. No signs of acute inflammation were found. While extending the elbow from full flexion with the forearm pronated, a cord like mass moving over the radial head with a painful snap was palpated. A plain X-ray revealed an exostosis in the radial neck. No abnormal pathology was found on an arthrogram. The conservative treatment with 1% xylocaine and steroid injection did not relieve the symptom and an operation was performed. In the operation, an enlarged annular ligament was found incarcerated, covering over the anterior part of the radial head in an extended position, which was reduced with a click to the normal position in the neck by 110° flexing. The snapping disappeared by excising the enlarged incarcerated part. At the last follow-up, 7 months after the operation, he was completely free from the symptoms.
The cause of a snapping elbow, a relatively rare disorder, can be either intraarticular or extraarticular. In our case, the exostosis around the radial neck made it shallower, increasing the possibility for the annular ligament to slip over the head into the joint.
