Osteonecrosis: Symptoms, Causes, Treatment
نخر العظم (النخر اللاوعائي)
Osteonecrosis, or avascular necrosis, is bone damage caused by disrupted blood supply. It may affect the femoral head or other bones. Diagnosis before joint-surface collapse allows discussion of joint-preserving options.
What is Osteonecrosis?
Bone is living tissue requiring blood and oxygen. An affected area can crack or collapse, particularly under weight-bearing stress. Osteonecrosis differs from osteoporosis and infection, and hip pain alone does not establish the diagnosis.
Related topic: Osteoarthritis: a condition distinct from osteonecrosis.
Symptoms
Early disease may be symptom-free. Pain can begin during walking or weight bearing and later occur at rest. Hip involvement may cause groin or buttock pain, stiffness or limping. A sudden increase in pain warrants reassessment.
Causes
Fractures or dislocation may interrupt blood flow. Nontraumatic cases are associated with systemic corticosteroids, heavy alcohol use, certain blood or immune disorders and some treatments. Sometimes no cause is identified. Never abruptly stop prescribed corticosteroids.
Risk factors
Important factors include joint injury, prolonged or high-dose systemic corticosteroids, heavy alcohol use, sickle cell disease and certain autoimmune illnesses. The full history matters; a risk factor does not make every episode of pain osteonecrosis.
Diagnosis
Assessment includes movement examination and injury, medication and medical history. X-rays are often first, but MRI can detect early disease despite normal radiographs. The affected area, stage and presence of collapse guide treatment decisions.
Treatment
Appropriate walking aids, reduced loading and selected pain relief may help symptoms but cannot restore dead bone. Early selected cases may benefit from core decompression or another joint-preserving procedure; advanced collapse may require replacement. Osteoporosis medicines are not a universally established treatment.
Complications
Progression can cause collapse beneath cartilage, arthritis, restricted movement and chronic pain. The pace varies, so one scan does not always predict the future course. Follow-up helps plan intervention and rehabilitation.
Prevention
Address modifiable risks, follow up injuries and associated diseases, and avoid excessive alcohol and smoking. A clinician should review corticosteroid need and dose; reducing it yourself can be harmful. No measure guarantees prevention in everyone at risk.
When to see a doctor
See an orthopaedic specialist for persistent joint or hip pain, especially with relevant risks. New inability to bear weight, severe post-injury pain or a hot joint with fever needs urgent assessment for fracture, infection or another cause.