Why does avascular necrosis of the hip cause hip pain?

The femoral head is the rounded top of the thigh bone that fits into the hip socket. It needs a steady blood supply to maintain healthy bone. In avascular necrosis, reduced blood flow can injure bone cells. The weakened area may hurt with weight-bearing and, as the condition progresses, the smooth shape of the femoral head can become less able to support the joint. Pain may be felt in the groin, outer hip, buttock, or thigh, and stiffness can limit walking or rotation.

Book a medical assessment for persistent or unexplained hip pain, especially if walking becomes difficult. Until reviewed, reduce high-impact activity and use support if advised. A clinician may assess movement, strength, walking pattern, and imaging findings. Treatment depends on the stage and cause; options can include activity changes, physiotherapy for safe function, medicines, or procedures discussed with an orthopaedic specialist.

Seek urgent care for sudden severe hip pain after an injury, inability to bear weight, a visibly shortened or rotated leg, fever with a hot swollen joint, or new weakness or numbness. Prompt review also matters when pain is steadily worsening or starts occurring at rest.

Ask what imaging is needed, whether the femoral head has changed shape, which activities are safe, and how treatment may protect mobility at your current stage.