Internal Medicine

0521779407-16 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:18

1106 Osteonecrosis

Signs and Symptoms

■Most commonly involves femoral head, but can involve femoral

condyles, humeral head, tibial plateau, small bones of hands/feet

■Gradual onset mild vague pain in groin or buttock

■Pain worse with activity

■Reduced exercise or activity

■Can progress to pain at rest or night

■Can develop limp, reduced ROM late in course

■Can be asymptomatic and discovered incidentally on radiographs

■Exam unremarkable early

■Late in course may have painful restricted joint motion

tests

■Basic Tests

➣None, except to evaluate risk factors

■Specific Diagnostic Tests

➣Biopsy and histology of bone, measurement of bone marrow

pressure, venography (invasive and rarely performed)

Imaging

■Plain x-rays:

➣Stage 0 and 1: normal

➣Stage 2: focal osteopenia, sclerosis, and cysts

➣Stage 3: radiolucent line under subchondral end plate (crescent

sign)

➣Stage 4: flattening of femoral head and collapse

➣Stage 5: joint space narrowing with secondary osteoarthritis

➣Stage 6: joint destruction

➣May not progress sequentially through all stages

■Radionuclide bone scans: may be positive in stages 1–6; useful in

stage 1 (cold spot) when radiographs are normal

■MRI:

➣Positive in stages 1–6

➣Useful in stage 1 when radiographs are normal

➣Sensitivity almost 100%

■CT:

➣Normal in stages 0 and 1

➣Used to define extent of bone changes in stages 2 and 4

■Symptoms may precede radiographic changes by months or years

■Radiographic abnormalities present in asymptomatic contralateral

hip in 30–70%