Coxa Vara

synonyms:

Coxa Vara ICD-9

Coxa Vara Etiology / Epidemiology / Natural History

• Defined as any decrease below the normal values of the neck-shaft angle of the proximal femur.
• Congital, progressive aoutosomal dominant developmental disorder, or a result of trauma, LCP diesae, SCFE, metabolic disorder, or neoplasm.
• Male = female, right = left
• 30%-50% bilateral

Coxa Vara Anatomy

• Slip occurs on the metaphyseal side of the epiphyseal plate, breaking away from the plate at its distal end to separate off a flake (triangular fragment) of metaphysis (the inverted 'Y')

Coxa Vara Clinical Evaluation

• Painless waddling or Trendelberg gait generally noted between 2-6 years old.
• Decreased hip abduction
• Limb-length discrepancy in unilatearl.

Coxa Vara Xray / Diagnositc Tests

• AP and lateral pelvis films, lateral can be frog-legged or cross table .
• Inverted Y pattern of the proximal formoral physis.
• Fairbanks Fragment: fragment at the inferior neck associated with invertd Y pattern.
• Hilgenreiner epiphyseal angle: angle between hilgenreiner's line and a lone drawn throught the proximal femoral phsis on AP pelvic view.

Coxa Vara Classification / Treatment

• Neck shaft angle >90° or Hilgenreiner angle < 45°
  -Treatment = observation
• Neck shaft angle <90° or Hilgenreiner angle >60° or 45° -60° with documented progression of varus deformity
  -Treatment: corrective intertrochanteric or subtrochanteric valgus osteotomy. Goal = Hilgenreiner's angle of 25° , neck shaft angle between 150° and 160°. Consider concomittant adductor tentomy, proximal femoral shortening. (Carroll J Pediatr Othrop 17:220;1997)
• Classic Radiographic findings: 
  -decreased femoral neck-shaft angle
  -vertical position of the physeal plate
  - triangular metaphyseal fragment in the inferior femoral neck surrounded by an inverted radiolucent Y pattern ( sine qua non of this condition)
  -decrease in normal anteversion of the proximal femur, may become true retroversion; coxa breva; and in some patients acetabular dysplasia

Coxa Vara Associated Injuries / Differential Diagnosis

• Proximal femoral focal deficiency
• Fibular hemimelia

Coxa Vara Complications

• Premature physeal closure
• Greater tochanteric overgrowth
• Recurrence of deformity
• Osteonecrosis
• Limb-length discrepancy, Degenerative arthritis

Coxa Vara Follow-up Care

Coxa Vara Review References

• Weinstein JN, JPO 1084;4:70
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