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How is Osteonecrosis treated
Medical management of Osteonecrosis
The goal in treating ON is to prevent bony collapse and subsequent deformity. Thus, effective treatment is contingent upon diagnosis while ON is still in its early stages (stage II and less). Patients on GC should be tapered to the lowest possible dose. Recommended medical management is limited to having the patient discontinue weight-bearing on the affected side for 4–8 weeks and administering analgesics for relief of associated pain. Unfortunately, hip survival rates with nonoperative management are only in the 13% to 35% range for stage I–IV disease. Therefore, nonsurgical management does not change the natural course of the disease. Recently there have been promising reports with pharmacologic therapies including lipid-lowering drugs, bisphosphonates, and anticoagulants, which should be considered. Hyperbaric oxygen, pulsed electromagnetic field therapy, and extracorporeal shock therapy are being investigated. The best results with any of these therapies are achieved in patients where the area of involvement of the femoral head is ≤15% and not involving the weight-bearing surface.
University of Pennsylvania (Steinberg) System of Staging of Osteonecrosis of the Femoral Head
| Stage | Plain Radiographic Findings | Magnetic Resonance Imaging a |
|---|---|---|
| 0 b | Normal | Normal |
| I | Normal | Abnormal |
| II | Osteopenia, bony sclerosis, cystic changes | Abnormal |
| III | Subchondral collapse (“crescent sign”) without articular surface flattening | Abnormal |
| IV | Flattening of the articular surface without joint-space narrowing | Abnormal |
| V | Flattening of the articular surface with joint-space narrowing and/or acetabular involvement | Abnormal |
| VI | Advanced degenerative changes | Abnormal |
a Each stage is further divided into three subclasses: A = small (<15% femoral head involvement, <2-mm depression of femoral head); B = moderate (15%–30%, 2–4 mm); C = large (>30%, >4 mm) depending on the size of the lesion on magnetic resonance imaging.
b Stage 0 refers to an “at risk” asymptomatic, uninvolved hip in an individual with avascular necrosis on the contralateral side.
