Avascular necrosis of hip

Background

Can be simplified to traumatic and nontraumatic causes that lead to an insult to the blood supply to the bone. The ischemia causes causes death of osteocytes and bone marrow which will eventually lead to necrosis of collapse of the dead segment.

Etiologies

• Traumatic causes
  • Femoral neck fracture/Dislocation

• Non-traumatic causes
  • Use of Corticosteriods, Alcohol, Tobacco
  • Systemic Lupus Erythematosus
  • Chronic Kidney Disease
  • Pancreatitis
  • Radiation therapy
  • HIV
  • Caisson Disease aka Dysbarism
  • Legg-Calve-Perthes disease
  • Idiopathic

Clinical Features

• Limp
• Limited range of motion of joint, both active and passive
• Pain: Knee, Thigh, and/or Groin
• Wasting of local musculature
• Asymmetric leg length

Evaluation

• Plain XR is poorly sensitive in early stages, as low as 41%
• Radiographic changes may be delayed by years
• MRI ~90% sensitivity and specificity

Disposition

• Initial supportive care until later stages of disease
• Orthopedic consultation for repeat imaging and risk stratification for surgical treatment

References

• JONES PHD, L. C. AND MONT MD, M. A. Osteonecrosis (avascular necrosis of bone) In-text: (Jones PhD and Mont MD) Your Bibliography: Jones PhD, Lynne C and Michael A Mont MD. "Osteonecrosis (Avascular Necrosis Of Bone)". UpToDate. N.p., 2016. Web. 31 July 2016.
• Kelly JD et al. Femoral head avascular necrosis treatment & management. Aug 16, 2015. http://emedicine.medscape.com/article/86568-treatment#showall.
• Stoica Z et al. Imaging of Avascular Necrosis of Femoral Head: Familiar Methods and Newer Trends. Curr Health Sci J. 2009 Jan-Mar; 35(1): 23–28.