OrthoNet

DDH-dysplasia
Approach to DDH - Acetabular Dysplasia

- after treating the dislocation, you must follow the kid to see if the acetabulum is developing normally.
Look to see what the pathology is:
- is it dysplasia of the acetabulum with a shallow cup - acetabular index down, sharp angle down?
- is it a coxa valga with superior loading?
- is it both?

- is the dysplasia causing recurrent instability? Then you better get on with an osteotomy
- if reduced, it is somewhat controversial to decide when to do the osteotomy - wait for remodeling, or just go ahead and do it to encourage better remodeling? Probably a more aggressive approach is warranted - if the acetabulum is not developing normally after a couple visits to the clinic, pull the trigger.

Reconstructive osteotomies.

- cannot have degenerative arthritis
- should have a good range of motion (how good is debatable)
- should check an abduction/internal rotation x-ray to assess two things: congruency and coverage. On this view the head and acetabulum should be CONGRUENT to proceed with a re-directional osteotomy (Salter, Triple, Steel). If reduced but not completely congruent, consider acetabuloplasty - Dega, Pemberton (more in the CMT or paralytic population). If not reducible - need a salvage procedure (Chiari or Shelf).
- look at the femoral neck shaft angle - is the deformity there? Does it need a varus osteotomy? Most have lots of anteversion and not that much valgus, so a varus osteotomy runs the risk of elevating their GT and causing an abductor limp. If doing a varus osteotomy, remember to medialize the femur with the offset on the plate.