Pelvic Osteotomies in Hip Dysplasia
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Direct answer
Pelvic osteotomies in hip dysplasia are bone cuts that reorient the acetabulum to improve femoral head coverage, chosen by the child's age, the reducibility of the hip and the pattern of acetabular deficiency. Salter's innominate osteotomy rotates the acetabulum in young children whose triradiate cartilage is still open. Chiari osteotomy suits incongruent hips, while triple osteotomy suits older children with a reducible hip.
What you must remember
- Salter osteotomy: an innominate osteotomy above the acetabulum that pivots on the pubic symphysis and is performed while the triradiate cartilage is still open.
- Pemberton osteotomy: a curved cut through the acetabular roof that extends lateral cover over the femoral head.
- Dega osteotomy: a posterosuperior acetabular osteotomy that reorients the roof to improve posterolateral cover.
- Chiari osteotomy: a medial displacement osteotomy that moves the femoral head medially under a new bony shelf, used for incongruent hips.
- Triple osteotomy: cuts through the ilium, ischium and pubis, freeing the whole acetabulum for rotation in older children and adolescents with a reducible hip.
- Reducibility: whether the hip reduces under anaesthesia decides between a containment osteotomy and a salvage procedure.
- Assessment: the acetabular index and centre-edge angle on radiographs quantify coverage before and after surgery.
Choosing an osteotomy for a child with dysplasia
A 6-year-old girl has a dislocated left hip that reduces under anaesthesia, and the radiographs show a shallow, deficient acetabulum. The choice of osteotomy follows from her age, the state of the triradiate cartilage and whether the hip stays reduced.
- Check reducibility: the hip is assessed under anaesthesia, and a hip that reduces well suits a containment osteotomy.
- Measure coverage: the acetabular index and centre-edge angle quantify the deficiency and set the target for correction.
- Consider age and the cartilage: Salter's osteotomy is used in young children while the triradiate cartilage is open, since the symphysis must still be supple enough to act as the pivot.
- Match the cut to the deficiency: the Pemberton or Dega osteotomy is chosen when the roof is deficient laterally or posterosuperiorly.
- Consider incongruence: a Chiari osteotomy is used when the femoral head cannot be kept concentric by a containment procedure.
- Plan for older children: a triple osteotomy corrects large rotational deficiency in older children and adolescents with a reducible hip.
- Plan for later: residual dysplasia or early osteoarthritis may need further surgery, such as periacetabular osteotomy or arthroplasty.
Where the exam tries to catch you
Osteotomy questions turn on age, the cartilage status and the reducibility of the hip.
- Trap: choosing a Salter osteotomy for an adolescent with closed triradiate cartilage Correct: Salter pivots on a supple symphysis and is used in younger children, so an older patient is better served by triple osteotomy.
- Trap: using a Chiari osteotomy for a hip that reduces easily Correct: Chiari is for incongruent hips with medial displacement, while a reducible hip is treated with a containment osteotomy.
- Trap: believing osteotomy alone treats every dysplastic hip Correct: an irreducible hip needs open reduction, and residual dysplasia may still require further surgery.
Frequently asked questions
Which osteotomy is used in young children with hip dysplasia?
Salter's innominate osteotomy is commonly used in young children with hip dysplasia and open triradiate cartilage. It rotates the acetabulum to improve anterior and lateral femoral head coverage.
What is the Pemberton osteotomy?
The Pemberton osteotomy is a curved cut through the acetabular roof that increases lateral coverage of the femoral head. It is used in dysplasia when the roof deficiency is lateral, and it hinges on the triradiate cartilage.
When is a Chiari osteotomy indicated in hip dysplasia?
The Chiari osteotomy is indicated for an incongruent hip in which the femoral head is subluxed or cannot be kept concentric. It moves the femoral head medially under a new bony shelf that provides cover.
What is the triple osteotomy in hip dysplasia?
Triple osteotomy cuts the ilium, ischium and pubis to free the whole acetabulum for rotation. It is used in older children and adolescents with a reducible dysplastic hip that needs large acetabular correction.