Extensive MRSA-positive sternoclavicular septic arthritis with uncommon origin: a case report

Sternoclavicular joint (SCJ) septic arthritis is a rare entity, representing less than 1% of all bone infections. It is generally associated with hematogenous spread from sources such as skin or soft tissue infections, intravenous drug use, or central venous access devices. Methicillin-resistant Staphylococcus aureus (MRSA) is an uncommon but aggressive pathogen in this setting.

We report the case of a 52-year-old male with a history of type 2 diabetes mellitus with poor glycemic control, hypertension, hypercholesterolemia, coronary artery disease, and prior lower-limb amputation who presented with an extensive MRSA-positive SCJ septic arthritis of unusual origin. The infection was traced to a chronically infected, non-healing amputation stump, which served as the hematogenous source, confirmed by hemoculture. Clinical examination, contrast-enhanced computed tomography (CT) imaging, and microbiological cultures confirmed extensive Osteomyelitis of the right sternoclavicular and first sternocostal joints, with a contiguous soft-tissue abscess extending from the upper arm to the neck. The patient underwent radical surgical debridement, including resection of the medial clavicle, first rib segment, and affected sternum, followed by vacuum-assisted closure therapy and prolonged intravenous vancomycin. Wound healing was achieved by secondary closure after granulation, and MRSA eradication was confirmed by repeat cultures. The source of the infection was also treated successfully to prevent recurrence of the inflammation.

This case highlights a rare hematogenous origin of MRSA SCJ septic arthritis from a chronically infected amputation stump. Early recognition, aggressive surgical management, targeted antimicrobial therapy, and multidisciplinary care were critical to preventing life-threatening complications.