Congenital Hip Dysplasia

• US
  • superolateral displacement of hip relative to acetabulum
  • axial and coronal views
  • measure alpha angle, normal is >60 degress
  • stress maneuvers: abnormal posterior and superior subluxation
• risk factors
  • family history
  • breech presentation
  • torticollis
  • foot and knee deformity
  • neuromuscular disease (myelodysplasia and arthrogryposis
• F>M, L>R
• screening exam at 4-6 weeks

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Femoroacetabular Impingement

• impingement of anterior labrum during hip flexion and internal rotation
• anterior osseous bulging of femoral head-neck junction
• excessively deep acetabulum with overgrowth of anterior superior acetabular rim )pincer-type)
• ~ herniation pit

Slipped Capital Femoral Epiphysis

• SCFE
• Salter-Harris I fracture with displacement
• capital femoral epiphysis slips posterior medial to neck
• findings
  • widening of physis
  • Klein line (lateral femoral neck line) DOES NOT cross femoral head
  • indistinct physis
• adolescents, males, blacks, obese, children with delayed skeletal maturation
• 20% bilateral
• internal pinning WITHOUT reduction; do not disrupt blood supply
• osteoarthritis in adulthood, risk of AVN

Hip Deformity Differential

• Avascular Necrosis
• Congenital Hip Dysplasia
• Legg Calve Perthe Disease
• SCFE

Femoral fractures

• MRI has highest sensitivity, specificity
• Bone scan highly sensitive after 72 hours
• CT scan not as sensitive as MRI
• femoral head fractures
  • associated with hip dislocation
• femoral neck fractures
  • the most common
  • elderly, osteoporosis
  • types: subcapital (MC), midcervical, and basicervical
  • more displacement, higher chance of AVN and nonunion
  • Garden Classification of Subcapital fractures
    • Stage I = incomplete lateral impaction fractures
    • Stage II = complete subcapital fractures without displacement
    • Stage III = complete subcapital fractures with partial displacement
    • Stage IV = complete subcapital fracture with gross proximal displacement of the shaft relative to the head
• intertrochanteric fractures
  • good prognosis
  • internal fixation with dynamic hip screw
• avulsion fracture of less trochanter
  • pediatrics
  • superior avulsion of less trochanter, pulled by iliopsoas
• femoral shaft fractures
  • often fragmented or butterfly
  • casting for pediatrics, intramedullary rod for adults
  • degree of rotation (version) is measured
• femoral condyle fractures
• stress fractures
  • detected on MRI
  • along medial femoral neck
  • become complete fractures, requiring pinning

Hip Dislocation

• ~ femoral head fractures
• delayed relocation increases risk of AVN

Posterior

• most common, 90%
• superior displacement of femoral head on frontal view
• femoral head may look smaller

Anterior

• flexed = obturator anterior dislocation
  • femoral head is medial and inferior
  • overlying obturator foramen
• extended = iliac dislocation
  • head is superior to acetabulum
  • femur is externally rotated; distinguish from posterior dislocation

Hip MRI Dictation

Clinical statement: [x]

Technique: [x]

Comparison: [x]

Findings: There is no greater trochanteric or iliopsoas bursitis. There is no stress fracture or osteonecrosis .

Images of the hip demonstrate no labral tear. The articular cartilage over the hip joint is maintained. There is no effusion or synovitis .

The fat planes around the sciatic nerves are preserved. The hamstring origins are normal. The sacroilliac joints are unremarkable.

Normal intervertebral T2 disc signal in the lower lumbar discs is maintained. No inguinal hernia or other pelvic pathology is identified.

Impression: [x]

Hip Plain Film Dictation

Indication: [x]
Technique: [x] views of the [x] hip. [An AP radiograph of the pelvis was obtained to assess joint symmetry].
Comparison: [x]
Findings: No fracture or dislocation is seen.. The hip joint is well-maintained.
Impression: No osseous or articular abnormalities of the [x] hip.