Attrition rupture of ulnar nerve in a patient with rheumatoid elbow arthritis: A case report

Cubital tunnel syndrome has been recognized as a common pathology in rheumatoid arthritis (RA) of the elbow. We encountered a patient with RA of the elbow showing attrition rupture of the ulnar nerve. This pathology is extremely rare, and we discussed preventive measures for similar cases in the future based on our case.

A 53-year-old woman, received drug treatment for RA since 30 years earlier, had numbness in the left ulnar nerve territory, dorsal interossei muscle atrophy, and resulting claw hand.

Plain x-ray examination showed bone destruction of the left elbow joint and marked osteophyte formation in the medial joint space. In nerve conduction velocity (NCV) tests, the Motor NCV was immeasurable in the ulnar nerve territory. Based on these findings, a diagnosis of left cubital tunnel syndrome was made, and anterior transposition of the ulnar nerve was planned.

When the ulnar nerve dissection was advanced, about 80% portion of the ulnar nerve was ruptured. After the ends of the divided nerve were freshened, end-to-end anastomosis was possible by anterior transposition of the ulnar nerve.

Two years after the operation, numbness and muscle atrophy also remained. There were no changes in the level of daily activities after the operation. However, motor NCV, showed improvement (22.8 m/s) after the operation.

In patients with RA showing ulnar neuropathy symptoms, marked osteophyte formation in the medial joint space or valgus deformity may indicate attrition nerve rupture. In the future, when such patients with RA are examined, active nerve exposure and dissection should be considered in terms of ulnar nerve protection.