Rapidly Progressive Femoral Head Destruction Following a Single Intra-Articular Corticosteroid Injection

Osteonecrosis of the femoral head is a well-recognized complication of corticosteroid exposure but it is more commonly associated with prolonged systemic therapy or high cumulative doses.Rapid femoral head destruction following a single intra-articular corticosteroid injection is uncommon.We present the case of a 47-year-old woman with severe right hip osteoarthritis and a remote history of right hip arthroscopy who underwent a fluoroscopy-guided intra-articular injection containing 80 milligrams (mg) of triamcinolone after persistent symptoms despite conservative management.Initial radiographs demonstrated severe osteoarthritis with superior femoral head flattening but without radiographic evidence of frank femoral head collapse or subchondral lucency.Although the patient experienced transient relief, repeat imaging 10 days after injection demonstrated interval femoral head deformity.Her symptoms and functional limitations progressed rapidly, and by approximately six weeks post-injection, imaging demonstrated near-complete destruction of the femoral head.Given the severity of her pain, functional decline, and rapid structural deterioration, she underwent total hip arthroplasty with subsequent improvement in pain and ambulatory function.The temporal relationship between corticosteroid injection and rapid femoral head destruction is notable; however, the absence of pre-injection magnetic resonance imaging (MRI) and histopathologic confirmation prevents determination of the underlying mechanism or establishment of a causal relationship.Pre-existing occult osteonecrosis, subchondral insufficiency fracture, and rapidly progressive osteoarthritis remain possible contributing or alternative processes.This case highlights the importance of recognizing unexpected clinical deterioration following intra-articular hip corticosteroid injections and considering advanced imaging when symptoms progress rapidly or are disproportionate to radiographic findings.