(Kiosk 2) Admitted for Spine Surgery, Discharged Needing a Hip Replacement (A Case Report)

Case Diagnosis: Rapid femoral head osteonecrosis (ON) following single intra-articular steroid injection.

Case Description or Program Description: An 80-year-old woman, with past medical history including osteoarthritis (OA); osteoporosis (on Abaloparatide); rheumatoid arthritis (in her wrists, on Baricitinib); right knee joint prosthesis infection; T10-pelvis revision fusion 5 years prior; initially presented with progressive back pain due to hardware failure and T10 compression fracture. She was admitted to acute inpatient rehabilitation (ARF) following T5-T10 revision fusion. Previously, she ambulated with a straight cane. Upon admission, she reported worsening right hip pain that hindered her ability to ambulate. Patient saw Orthopedics 2 months prior for this, at which time XRay showed a fully formed right femoral head with moderate-to-severe hip joint OA, and she received a corticosteroid injection. Repeat XRay showed ON of the right femoral head concerning for rapid-interval femoral head collapse. Workup was initiated but equivocal for infection. Patient denied history of prolonged steroid use, alcoholism, or bisphosphonate use. Ultimately, Orthopedics performed irrigation and debridement, resection of the remaining femoral neck and head, biopsy/culture, and placement of an articulating cement spacer to the Right hip. Diagnosis was presumed septic versus aseptic arthritis, for which she was started on a prolonged course of intravenous antibiotics. Once medically cleared, she was discharged back to ARF, with instructions to schedule total hip arthroplasty.

Setting: acute inpatient rehabilitation

Assessment/Results: Surgical pathology did not grow any organisms, but did show acute/chronic osteomyelitis, destructive bony changes, necrotic bone fragments in soft tissue, and hyperplastic synovium with granulation tissue changes.

Discussion (relevance): There are a limited number of cases of femoral head ON following single intra-articular steroid injection. It is a rare but significant complication that can result in poor functional outcomes and significant morbidity.

Conclusions: In this particular case, while the exact etiology remains uncertain, the patient improved with long term antibiotics, total joint replacement and ARF.