PANCE Blueprint Musculoskeletal (10%)

Avascular necrosis hip

Patient will present as → a 49 yo female with progressive left hip pain and limp which has become progressively worse over 13 months. Her past medical history is significant for heterozygous sickle cell anemia and she is has been under hydroxyurea treatment for about 20+ years. She is on no other medication and denies alcohol or tobacco use. The pain is localized to the groin, lateral hip, and buttocks and she reports a sudden increase in pain about two months ago after her last sickle cell crisis. Physical exam reveals a left hip with painful restriction of ROM and a limp. Right hip has mild symptoms. An MRI is performed with results seen here.

Insidious onset of a dull ache or throbbing localized to the groin, lateral hip, or buttocks - think trauma, steroid use, or sickle cell.

  • AVN will start as groin pain that is followed by thigh and buttocks pain, associated with weight-bearing activities that progresses to pain at rest and night pain.
  • Risk factors: steroids, SLE, hypercoagulable states, irradiation, trauma, hematologic diseases (leukemia, lymphoma), dysbaric disorders (decompression sickness, "the bends"), and sickle cell disease.
  • In children AVN is known as Legg-Calve' Perthes disease - will present with persistent pain and a limp. Ages 2-11 years old with a peak incidence of 4-8 years of age.

MRI is the study of choice for early detection - order when radiographs negative and osteonecrosis still suspected.

  • Radiographs: AP hip, frog-lateral of hip, AP and lateral of contralateral hip.
  • Bone scan.

Treatment may be conservative or may eventually need joint replacement

  • Bisphosphonates - indicated for precollapse AVN
Question 1
Identification of hip fracture and initiation of treatment is imperative to avoid such complications as avascular necrosis (AVN). Which of the following groups are most at risk for AVN?
Children and adolescents
Adults in middle age
The elderly
Question 1 Explanation: 
AVN is more common in patients in the pediatric and adolescent age groups. This outcome is due to the precarious nature of the blood supply to the subchondral region of the femoral head, which does not stabilize until years after skeletal maturity, after which collateral flow develops.
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Disorders of the hip (PEARLS) (Prev Lesson)
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