Progressive osteolysis and surface chondrolysis of the proximal humerus following influenza vaccination.

Influenza vaccination is a common annual event among individuals in the United States. Complications, although infrequent, are usually mild and self-limiting. This article describes the case of a 46-year-old man who experienced progressive osteolysis and surface chondrolysis of the proximal humerus following routine influenza vaccination. The patient presented with shoulder pain and limited range of motion 3 weeks following vaccination in the deltoid area. No skin changes were noted, inflammatory markers were normal, and the patient's pain and disability persisted despite nonsteroidal anti-inflammatory drugs and occupational therapy. Plain radiographs revealed a small lytic area involving the greater tuberosity of the humeral head. Magnetic resonance imaging (MRI) showed abnormal uptake and cystic changes involving the greater tuberosity of the humeral head; repeat MRI at 5 months showed progression in the cystic changes. Diagnostic arthroscopy of the shoulder revealed a hyperemic joint capsule and extensive, full-thickness chondrolysis of the humeral head. Cystic biopsy demonstrated inflammatory cells and granulation tissue, consistent with foreign body response. Cultures were negative. Surgical debridement of the cystic areas and resurfacing of the humeral head yielded a good outcome. To our knowledge, this is the first reported complication of influenza vaccination requiring surgical intervention. Physicians need to be aware of the potential for osteolysis and chondrolysis, which may require aggressive forms of management.