DDH Pelvic Osteotomies - Presentation Bullet Points

1. Salter Innominate Osteotomy

• Complete transverse cut through the full thickness of the innominate bone from just above the anterior inferior iliac spine to the sciatic notch; the pubic symphysis acts as the hinge, rotating the entire acetabulum anterolaterally to improve coverage of the femoral head.
• Indications: Age 18 months to 6 years; congruous concentric hip reduction; anterolateral acetabular deficiency; acetabular index correction needed of less than 10-15 degrees.
• Provides up to 20-25° of lateral and 10-15° of anterior coverage; requires a triangular iliac bone graft and internal fixation (pins) to hold correction; may lengthen the limb up to 1 cm.
• Does not cause acetabular retroversion due to the direction of fragment displacement; adductor/iliopsoas tenotomy and capsulorrhaphy are performed concurrently when needed.

2. Triple Innominate Osteotomy (Steel / Tönnis)

• Three separate cuts divide the ischium, superior pubic ramus, and ilium above the acetabulum, freeing the entire acetabular segment for three-dimensional reorientation - unlike Salter, which is constrained by the pubic symphysis.
• Indications: Older children and adolescents (triradiate cartilage open in Steel; Tönnis variant usable with open or nearly closed cartilage) with residual dysplasia where the symphysis is too rigid to permit adequate rotation with a single innominate osteotomy.
• Places articular cartilage - not fibrocartilage - over the femoral head; the repositioned segment is secured with a bone graft and metal pins; requires internal fixation due to instability of the free segment.
• Technically more demanding than Salter; risk of avascular necrosis of the acetabular fragment if blood supply is compromised; superseded in skeletally mature patients by the Ganz periacetabular osteotomy.

3. Pemberton Pericapsular Osteotomy (Acetabuloplasty)

• Incomplete osteotomy starting 10-15 mm above the AIIS, cut through the full thickness of the ilium and curving posteriorly to terminate at the ilioischial limb of the triradiate cartilage, which serves as the hinge; the acetabular roof is levered anterolaterally and inferiorly.
• Indications: Age 18 months to ~12 years (girls) / 14 years (boys) while triradiate cartilage remains supple; moderate-to-severe dysplasia with AI correction >10-15° needed; particularly useful for a small femoral head in a large acetabulum.
• Reduces acetabular volume (~14%) and changes acetabular shape - produces some joint incongruity that requires remodeling; does not require internal fixation (triradiate cartilage is a stable hinge), sparing the patient implant-removal surgery.
• Primarily improves superior-anterior coverage; overcorrection risks FAI later in life (though FAI is uncommon at 10-year follow-up); bone graft from ilium or femoral shortening osteotomy holds the correction open.

4. Dega Transiliac Osteotomy

• Incomplete transiliac osteotomy cutting through the anterior and middle portions of the inner cortex of the ilium only; the posteromedial iliac cortex and sciatic notch are left intact as the hinge, giving it a variable pivot point that allows selective anterolateral or posterior coverage.
• Indications: Residual acetabular dysplasia in DDH; particularly favored for neuromuscular hip dislocation (e.g., cerebral palsy) and cases with posterior acetabular deficiency; can be used with either open or closed triradiate cartilage (though usually done before closure).
• Reduces acetabular volume (~19%); improves superior, superior-anterior, and anterior coverage; the intact sciatic notch means the osteotomy is inherently stable - no internal fixation required; long-term 40-year outcomes are favorable when combined with open reduction and femoral osteotomy.
• Factors for early failure include older age at surgery, bilateral involvement, and higher-grade osteonecrosis.

5. Chiari Medial Displacement Osteotomy

• A salvage osteotomy in which a transverse cut is made at the level of the acetabular roof (just above the capsule); the entire lower hemi-pelvis including the femoral head is displaced medially, so the inferior surface of the proximal iliac fragment becomes a bone shelf over the femoral head.
• The new "acetabular roof" is covered by joint capsule (fibrocartilage), not hyaline cartilage - this is the fundamental limitation; metaplastic fibrocartilage gradually covers the interposed capsule and can provide reasonable medium-term function.
• Indications: Age >10 years (most series) with symptomatic subluxation/incongruent hip; dysplasia too severe for redirectional osteotomy; also used for irreducible dislocations where other osteotomies would not produce a congruous joint; may improve acetabular bone stock for future total hip arthroplasty.
• Does not require internal fixation in the classic description; medial displacement also reduces the abductor lever arm moment and may increase Trendelenburg gait temporarily; not recommended in children under 4-10 years when reconstructive options remain.

6. Shelf Procedure (Staheli Slotted Acetabular Augmentation)

• A lateral acetabular extension created by cutting a slot exactly at the acetabular margin (1 cm deep) and packing thin corticocancellous iliac strut grafts into the slot, mushrooming outward over the femoral head; position and width of coverage are determined preoperatively from the center-edge angle of Wiberg.
• Like the Chiari, coverage is provided by bone graft + interposed fibrocartilaginous capsule rather than native articular cartilage; primarily indicated when a deficient acetabulum cannot be corrected by redirectional osteotomy and the femoral head/acetabulum are misshapen but congruent.
• Contraindications: Dysplastic hips with spherical congruity suitable for redirectional osteotomy; hips needing concurrent open reduction requiring supplementary bony stability; patients unsuited for spica cast immobilization.
• The slot and graft size are fully adjustable intraoperatively (anteriorly for excess anteversion, posteriorly for posterior deficiency), making it versatile; requires spica cast for 6 weeks postoperatively.

7. Modified San Diego Acetabuloplasty

• Mubarak's modification of the Dega osteotomy: the inner cortex is kept bicortical only at the AIIS anteriorly and the sciatic notch posteriorly, with the unicortical mid-section between; three unequal triangular bone wedges allow selective customization of coverage direction simply by varying graft size and placement.
• Originally designed for neuromuscular hip dysplasia (CP) where deficiency is posterosuperior or direct lateral (vs. the anterolateral deficiency of idiopathic DDH); later expanded to idiopathic DDH with anterior and anterolateral deficiency.
• Placing the largest graft anteriorly increases anterolateral coverage; placing the largest graft posteriorly increases posterosuperior coverage - this directional flexibility is the key advantage over standard Dega or Pemberton.
• Reduces acetabular volume (~19%); improves posterior, superior-posterior, and superior coverage - the best posterior coverage among all acetabuloplasty types; used typically in the same age range as Dega (triradiate cartilage open preferred).