Rapid and Severe Idiopathic Aseptic Necrosis of the Contralateral Femoral Head after Unilateral Total Hip Arthroplasty.

Background: Osteonecrosis of the femoral head (ONFH) is a multifactorial disease, and agnogenic ONFH, otherwise known as idiopathic ONFH, is rare in clinic. Idiopathic ONFH that exhibits severe necrosis and progresses extremely rapidly is called rapidly destructive hip disease (RDHD). RDHD greatly affects patients but is rarely reported in clinical practice and literature.

Case Presentation: In this study, a 64-year-old male patient with complete collapse and necrosis of the right femoral head complicated with severe bone destruction at 10 months after left total hip arthroplasty (THA) was reported. The period from the intact structure of the right femoral head to the first discovery of its complete collapse, according to imaging results, was 7 months. The duration from the occurrence of symptoms in the right hip joint to the first discovery of complete collapse and necrosis of the femoral head was only 5 months. At present, the cause has not been determined based on medical history, symptoms, signs, imaging evaluation results, laboratory examination results, and pathological examination results, though it has been identified as severe idiopathic aseptic necrosis of the femoral head with rapid progression, or RDHD. Finally, right THA was performed, and a good outcome was observed in the patient at present.

Conclusions: As a rare hip joint disease, RDHD greatly influences the normal life of patients. RDHD of the contralateral side after unilateral THA is even scarcer. Left THA may be one of the important factors accelerating the necrosis of the right femoral head. Hopefully, with this case report, more attention will be paid to the contralateral hip joint in patients undergoing unilateral THA by clinicians and rehabilitation physicians, and a clinical reference will be provided for the research on RDHD.