Hip avascular necrosis, also known as osteonecrosis, is a condition that occurs when the blood supply to the head of the femur (the ball of the hip joint) is interrupted. Without adequate blood flow, the bone tissue begins to die and eventually collapses. If the bone collapses, the overlying joint cartilage also fails, leading to severe and rapid-onset arthritis.
In its earliest stages, AVN may cause no symptoms. However, as the disease progresses and the bone weakens, patients typically notice:
Deep Groin Pain: A dull ache or throbbing pain that is felt deep in the groin or buttock area.
Pain with Weight-Bearing: Discomfort that intensifies when standing or walking but may improve with rest.
Progressive Stiffness: Increasing difficulty moving the hip as the bone surface becomes irregular.
Night Pain: Pain that persists even while lying down, often interfering with sleep.
Sudden Increase in Pain: A sharp, dramatic worsening of symptoms which often signals that the bone has micro-fractured or collapsed.
Because early-stage AVN often does not show up on standard imaging, specialized tests are frequently required for an accurate diagnosis.
Physical Exam
X-rays: While useful for identifying late-stage bone collapse or arthritis, X-rays often appear normal in the early stages of the disease.
MRI: The most sensitive tool for detecting AVN. It can identify changes in the bone marrow and blood flow long before the bone actually collapses.
The goal of treatment is to prevent the femoral head from collapsing and to preserve the natural joint.
Activity Modification: Using crutches or a walker to reduce weight-bearing and slow the progression of bone damage.
Physical Therapy: Exercises designed to maintain joint mobility and strengthen the supporting muscles without overloading the bone.
Core Decompression: A surgical procedure where the inner cylinder of the bone is removed to reduce pressure and allow new blood vessels to form.
Bone Grafting: Transplanting healthy bone tissue to the affected area to provide structural support.
Total Hip Replacement: The standard treatment if the femoral head has already collapsed or if severe arthritis has developed.