Cubital tunnel syndrome associated with calcium pyrophosphate dihydrate crystal deposition disease.

Nine patients (11 elbows) presented with cubital tunnel syndrome that was complicated by calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. Their age ranged from 63 to 86 years, and 8 of the 9 patients were more than 70 years old. X-ray film examination demonstrated the presence of CPPD crystal deposition not only in the elbow but also in the knee, wrist, or spine in all patients. Medial epicondylectomy was performed in 8 patients (9 elbows), while 1 patient with both elbows affected was treated conservatively at his request. Thickening of the ulnar collateral ligament and synovium due to CPPD crystal deposition and degenerative joint changes induced protrusion of the floor of the cubital tunnel, resulting in ulnar neuropathy in these patients. The ulnar nerve was compressed between the protruded floor and fibrous band. Though various causes of cubital tunnel syndrome have been reported, findings of this study indicate that CPPD crystal deposition disease should also be considered a cause of this syndrome.