Why Does Avascular Necrosis of the Femoral Head Cause Hip Joint Effusion?
Disease description:
My father has developed avascular necrosis of the femoral head. During a recent examination, joint effusion in the hip was detected. Why does avascular necrosis of the femoral head lead to hip joint effusion?
Doctor's answer (1)
Dr. Li Bo
Hip joint effusion caused by avascular necrosis of the femoral head occurs because the hip joint bears substantial weight and is therefore more susceptible to injury. The synovium—primarily distributed around the joint and communicating directly with the joint cavity—secretes synovial fluid to lubricate the joint. Consequently, inflammation or injury can trigger excessive synovial fluid accumulation, leading to hip joint effusion. For some patients with avascular necrosis of the femoral head, hip joint effusion is a characteristic clinical manifestation. Additionally, conditions such as osteophyte formation (bone spurs), arthritis, rheumatic diseases, and traumatic injuries may irritate or damage the synovium, provoking an inflammatory response; in turn, the synovium responds to this inflammation by secreting exudative fluid, thereby causing hip joint effusion.
