View source for Avascular necrosis of hip

==Background==
Traumatic and nontraumatic causes can lead to an insult to the blood supply of the joint. The ischemia causes death of osteocytes and bone marrow that leads to necrosis and eventual collapse of the dead segment.

[[File:Osteonecrosis of Hip.jpg|thumb|Kupe MD. Hip Fracture. http://drkupe.blogspot.com/2011/03/hip-fracture.html. Accessed July 31, 2016.]]

===Epidemiology===
*Estimate of 10,000 to 20,000 new cases per year
*Responsible for about 10% of all total hip replacements
*Patients typically diagnosed before 40 years of age

===Etiologies<ref>*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.</ref>===
'''Traumatic causes
*[[Femoral neck fracture]]/[[Hip dislocation|dislocation]]
'''Non-traumatic causes'''
*Use of [[corticosteroids]], [[alcohol]], tobacco
*[[Systemic lupus erythematosus]]
*[[Sickle cell disease]]
*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

==Differential Diagnosis==
{{Hip pain DDX}}

==Evaluation==
*Plain XR is poorly sensitive in early stages, as low as 41%
**AP and Frog leg views
[[File:Osteonecrosis femur 1.jpg|thumb|Plain XR Osteonecrosis Femur by JMarchn(own work)]]

*MRI ~90% sensitivity and specificity
**Best test
[[File:Osteonecrosis MRI femur 2img.jpg|thumb|MRI Osteonecrosis Femur by JMarchn (ownwork)]]

*Bone Scan (aka Bone Scintigraph)
**May show evidence of early bone ischemia

==Management==
*Nonsurgical 
**Considered ineffective at stopping progression of ischemia
**Bedrest, limit weightbearing, pain control
*Medications
**Bisphophonates, vasodilators, and anticoagulants have been used but efficacy has not yet been proven
*Surgical
**Total Join Replacement
**Unfortunately, patients with osteonecrosis have an increased failure rate of the procedure. 
*On going research for treatment
**Joint preserving operations, Bone marrow decompression therapy, vascularized and nonvascularized bone grafts, Bone marrow grafting, and Osteotomy

==Disposition==
Medical and orthopedic referrals for evaluation of comorbidities and evaluation of joint should be made in the emergency department.

==See Also==
*[[Hip pain]]

==References==
<references/>
*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.
*Wainwright A. Legg-Calve-Perthes disease diagnostic tests - Epocrates online. Epocrates. https://online.epocrates.com/diseases/75134/Legg-Calve-Perthes-disease/Diagnostic-Tests. Accessed July 31, 2016.


[[Category:Orthopedics]]