Avascular necrosis (AVN), also called osteonecrosis, occurs when the blood supply to a bone is disrupted, causing bone cell death and progressive structural collapse. The femoral head (hip) is the most commonly affected site, but the humeral head (shoulder), femoral condyle (knee), and talus (ankle) can also be affected. AVN is associated with corticosteroid use (the leading cause), alcohol excess, sickle cell disease, trauma (femoral neck fracture), and various rheumatological conditions including SLE and antiphospholipid syndrome.
Stages of AVN and Cane Use
The Ficat-Arlet classification stages AVN from preclinical (Stage 0: MRI only, no X-ray changes) to collapsed femoral head with secondary osteoarthritis (Stage IV). Cane appropriateness and urgency changes by stage:
| Ficat Stage | X-ray / MRI Findings | Weight-Bearing Status | Cane Role |
|---|---|---|---|
| Stage 0 (Preclinical) | MRI changes only; no symptoms or minimal | Full | Cane not yet needed; activity modification may be advised |
| Stage I | MRI changes; no X-ray collapse; pain begins | Full but painful | Cane recommended to reduce femoral head loading during pain phase |
| Stage II | X-ray shows sclerosis / cysts; no collapse | Full but increasingly painful | Cane essential; reduces joint reaction force from 3-5x to 2-3x body weight |
| Stage III | Crescent sign; subchondral collapse beginning | Painful; may be restricted | Cane essential; partial offloading; surgical options being considered |
| Stage IV | Femoral head collapse; secondary OA | Severely limited | Cane as bridge to surgery (hip replacement); post-surgical walking aid |
Which Side for the Cane in AVN
The cane should be held in the hand contralateral to the affected joint. For AVN of the femoral head, contralateral cane use reduces the hip abductor muscle force required during single-leg stance, directly reducing the hip joint reaction force. This is the primary mechanical mechanism by which a cane slows AVN progression in early stages.
Bilateral AVN: A Common Problem
Corticosteroid-induced AVN is frequently bilateral: both femoral heads can be affected simultaneously, often asymmetrically (one more advanced than the other). In bilateral AVN, a single contralateral cane is not sufficient if both hips are significantly painful. Bilateral canes or crutches may be needed; a rollator is an alternative for those with severe bilateral involvement.
AVN in Sites Other Than the Hip
Knee AVN (femoral condyle, tibial plateau) presents with acute, severe knee pain in older women (spontaneous osteonecrosis of the knee, SONK) or as a corticosteroid complication. A contralateral knee cane reduces tibial plateau loading. Shoulder AVN (humeral head) affects cane use differently: pain in the cane-carrying arm may limit use of the contralateral cane; a forearm crutch distributes load to the forearm rather than the shoulder.
Explore DaiWalk walking canes. Related: Walking Cane for Hip Osteoarthritis | Walking Cane for SLE.
