Case report: subacute synovitis of the knee after a rose thorn injury: unusual clinical picture.

Synovitis secondary to penetrating plant thorn injuries is not frequently reported. Historically, it is considered aseptic and treated with removal of the intraarticular foreign body and affected synovial lining. We report a 57-year-old healthy man who was admitted 2 weeks after being injured by a rose (Rosacea) thorn with subacute and mild synovitis with effusion of his right knee. No intraarticular foreign body was retained. Pantoea agglomerans was identified in the synovial fluid. Contrary to former teaching, effusions from joints violated by thorns should not be presumed sterile. Bacterial growth is reported infrequently, but when reported, Pantoea agglomerans is the most common organism found. We recommend removal of foreign bodies if present, arthroscopic total synovectomy, and beginning empiric antibiotic treatment with coverage against gram-negative enteric pathogens in all cases of thorn synovitis until the results of culture specimens are known. Improved physician awareness can result in more rapid diagnosis and improved clinical outcome in affected individuals.