Radiographic changes occurred in 3 shoulders after injections of 0.5%pyoctanine solution for an intraoperative color arthrography.
Case 1: A 65-year-old man with a rotator cuff tear was operated on in 1991. A full-thickness tear was found by an intraoperative color arthrography. Two years later, he felt pain in his right shoulder again. A total shoulder arthroplasty was done in 1996.
Case 2: An acromioplasty was performed on a 56-years-old woman with subacromial bursitis in June 1992. The absence of a full-thickness tear was confirmed by a color arthrography. In 1995, she felt right shoulder pain again, and a total shoulder arthroplasty was performed.
Case 3: In July 1993, a 47-year-old woman felt some right shoulder pain after a fall on her right hand. She was operated on for a full-thickness cuff tear in September 1993. A tear site was identified by a color arthrography. Although she felt no pain for 3 years after the operation, she developed motion pain in her right shoulder in October 1996. Her pain was partially relieved by medication. Findings of these patients were compared with those of 5 patients with primary osteoarthritis (OA) of the shoulder. In pyoctanine arthropathy, plain radiographs showed a joint space narrowing, and subchondral bone atrophy. Peripheral osteophytes which were seen in OA at the inferior margin of the joint were not evident in the arthropathy. On T1-weighted MR images, small round areas with iso-signal-intensity to muscle were detected in the subchondral bone of the arthropathy joint. They showed high-signal intensity on T2-weighted images. Such findings were not found in OA shoulders. Histologic sections showed dominant cartilaginous destruction replaced by granulation in the arthropathy joints. These findings suggested different pathogenesis of pyoctanine arthropathy from that of OA shoulders.
