Physical examination for avascular necrosis of the femoral head

Physical examination for avascular necrosis of the femoral head (ANFH) is an essential component of the diagnostic evaluation and focuses on identifying signs of hip joint dysfunction, pain, and functional impairment. During the exam, the clinician typically begins with observation for limb-length discrepancy, muscle atrophy—particularly in the gluteal and quadriceps musculature—and gait abnormalities such as antalgic gait or Trendelenburg gait. Palpation may reveal localized tenderness over the anterior groin, lateral hip, or buttock, though tenderness is often subtle in early disease.

Range-of-motion assessment is critical: patients commonly demonstrate progressive limitation in internal rotation and flexion of the affected hip, often before significant pain onset. Painful arc testing—especially during combined flexion, adduction, and internal rotation (FADIR)—can reproduce symptoms and suggest intra-articular pathology, including early ANFH. Passive motion may elicit discomfort even when active movement appears preserved. In advanced stages, fixed deformity, severe restriction of motion, and crepitus may be present.

Special tests—including the log roll test, Thomas test, and resisted straight-leg raise—help differentiate hip pathology from referred pain originating from the lumbar spine, sacroiliac joint, or proximal thigh musculature. Neurovascular assessment is also performed to rule out compressive or systemic contributors. Importantly, physical findings often lag behind radiographic changes; thus, a normal exam does not exclude early ANFH, especially in high-risk patients (e.g., those with corticosteroid use, alcohol use disorder, sickle cell disease, or prior hip trauma). Imaging—particularly MRI—is required for definitive diagnosis when clinical suspicion remains high despite inconclusive physical findings.