AVN of the femoral head

Question 1

Hx

Answer 1

60 yr old F gradual onset L ant hip pain over past 6 months. Increasing problems with stairs and walking up hills, r hip beginning to bother her, low dose prednisolone for the past 10 yrs for idiopathic pulmonary fibrosis

Question 2

Look/ inspection

Answer 2

antalgic gait and leg length discrepancy

Question 3

active and passive movement

Answer 3

pain limited ROM L hip greater than R

Question 4

DDx

Answer 4

AVN femoral head secondary to steroids
Hip OA
Metastatic disease

Question 5

Why is AVN hips secondary to steroid use?

Answer 5

known SE of prolonged steroid use

pain limited active and passive range of motion

Question 6

Why is hip OA unlikely?

Answer 6

AVN more likely with prolonged oral steroid use

Question 7

Mets/ primary neoplastic disease

Answer 7

a/w rest pain

w/ rest pain, night sweats, fever, malaise

Question 8

Investigations

Answer 8

Xray AP Pelvis, frog leg lateral views of affected and contralateral hip
DEXA scan
Concern for neoplasm - Bence Jones protein, serum protein electrophoresis for multiple myeloma
hypercalcaemia
anaemia
thrombocytopenia

Question 9

Non-op tx

Answer 9

bisphosphonates for pre-collapse vascular necrosis

Question 10

op tx

Answer 10

core decompression +/- bone grafting [early AVN, stimulates healing via angiogenesis]
THR [younger pts, pts >65 with large lesions]
Total hip resurfacing [C/I in AVN secondary to long term steroids]
Hip arthrodesis [v young pt in labour intensive occupation]