Stages of AVN: From Early Signs to Advanced Bone Collapse

Understanding how bone damage progresses

Avascular Necrosis (AVN) is a condition where blood supply to the bone is interrupted, causing the bone tissue to weaken and eventually collapse. What makes AVN particularly challenging is that it progresses silently in stages. At first, the signs are subtle often mistaken for muscle strain or fatigue. But as the condition advances, it can lead to severe joint damage and disability.

By understanding the stages of AVN, patients can recognize the early warnings, seek timely diagnosis, and explore treatment options before significant damage occurs.

Stage 1: Silent Beginnings

Inside the bone:
The earliest stage of AVN begins with reduced blood flow to the bone. The tissue is starved of oxygen, but the bone’s shape and surface remain intact.

Symptoms:

• Mild or occasional joint pain, often after activity.

• Stiffness that comes and goes.

• Pain that feels unusual compared to regular fatigue or strain.

Diagnosis:

• X-rays usually appear normal.

• MRI scans are the most reliable tool to detect changes at this stage.

Treatment focus:
This is the most favorable stage for non-surgical treatment. Options include:

• Medications to improve blood flow and reduce pain.

• Lifestyle changes (avoiding alcohol, managing weight, limiting steroid use).

• Physiotherapy to maintain joint strength and flexibility.

Stage 2: Structural Weakness Appears

Inside the bone:
As blood deprivation continues, small cracks start forming in the bone structure. The smooth, rounded bone head weakens but has not collapsed yet.

Symptoms:

• More frequent pain, especially during weight-bearing activities.

• Discomfort spreading to nearby areas (like groin, thigh, or shoulder depending on the joint affected).

• Early signs of limping or stiffness.

Diagnosis:

• X-rays may now reveal density changes within the bone.

• MRI scans confirm the extent of damage.

Treatment focus:
At this stage, doctors may recommend:

• Core decompression surgery (drilling tiny holes in the bone to relieve pressure and restore blood flow).

• Stem cell or biologic therapies in some centers to support bone healing.

• Pain management with medications and targeted physiotherapy.

Stage 3: Bone Collapse Begins

Inside the bone:
The weakened bone surface starts to collapse under pressure, creating irregularities in its shape. The protective cartilage begins to deteriorate, making joint movement more painful.

Symptoms:

• Persistent pain, often even at rest.

• Difficulty walking, climbing stairs, or carrying out normal activities.

• Reduced mobility and a noticeable limp.

Diagnosis:

• X-rays clearly show deformities and collapsed areas.

• MRI provides detailed assessment of bone and cartilage damage.

Treatment focus:

• Osteotomy (reshaping the bone to shift weight away from damaged areas).

• Surgical procedures to delay or prevent joint replacement.

• Pain control and physiotherapy to preserve remaining function.

Stage 4: Advanced Collapse and Arthritis

Inside the bone:
By the final stage, the bone head has flattened significantly. Cartilage is severely damaged, joint space is reduced, and arthritis sets in. Movement becomes restricted and painful.

Symptoms:

• Severe, constant pain affecting daily life and sleep.

• Limited ability to walk without assistance.

• Stiffness and difficulty with basic movements.

Diagnosis:

• X-rays show advanced collapse, joint narrowing, and arthritis changes.

Treatment focus:

• Total joint replacement surgery (hip, knee, or shoulder depending on the affected joint).

• Post-surgical rehabilitation to regain strength and mobility.

• Long-term strategies to protect the new joint.

Why Understanding the Stages Matters

AVN doesn’t progress overnight; it can take months or years to move from early discomfort to full bone collapse. Recognizing the stages is critical because:

• Stage 1 and 2: Non-surgical treatments and regenerative therapies have the best chance of success.

• Stage 3: Bone-preserving surgeries can delay joint replacement but options narrow.

• Stage 4: Joint replacement often becomes the only effective solution.

Knowing where you stand helps in making informed decisions about treatment.

Listening to Your Body

AVN symptoms can be subtle in the beginning, but they gradually intensify. Common signals include:

• Persistent joint pain that doesn’t go away with rest.

• Limping or stiffness that becomes noticeable.

• Pain radiating to nearby areas.

• Discomfort severe enough to disturb sleep.

Paying attention to these signs and seeking medical evaluation early can help preserve bone health and delay the need for surgery.

Final Thoughts: Acting Early Saves Joints

AVN is a condition where timing is everything. The earlier it is detected, the greater the chances of saving the natural joint. While advanced stages may require surgical intervention, early detection and management can significantly improve quality of life.

If you experience persistent, unexplained joint pain especially in weight-bearing areas like the hip or knee don’t ignore it. An early MRI and consultation with a specialist could make the difference between preserving your bone and facing joint replacement.

Awareness of the stages is not just medical knowledge it’s the first step toward taking control of your joint health before the collapse begins.