1. Alternatives to Periacetabular Osteotomy (PAO) for Adult Acetabular Dysplasia
Cara Beth Lee, MD
Michael B. Millis, MD
Director, Center for Hip Preservation, Department of Orthopedics, Virginia Mason Medical Center, Seattle, Washington
Hip and Pelvis Clinic , Chonbuk University Hospital , Jeonju, Korea .

2. Introduction
Salter
Instability in the dysplastic hip is caused by inadequate anterior and lateral femoral head coverage
Modification of Salter’s osteotomy technique have led to improvements in correcting the components of the dysplastic hip
In the US, periacetabular osteotomy is currently the most commonly used reorientation procedure for adult acetabular dysplasia

3. Periacetabular osteotomy
PAO is single surgical approach
has ability to obtain a large, multiplanar correction
preserves the acetabular blood supply
maintains posterior column integrity
conserves the true pelvis
With modification of original technique, additional advantage
Rotational acetabular osteotomy
Triple Pelvic Osteotomy
Chiari Pelvic Osteotomy

4. Rotational Acetabular Osteotomy
Using specially curved osteotomies that follow its circumference
Approximately 1.5 cm proximal to the acetabular roof
Wagner’s method uses an extensive anterior iliofemoral approach to expose the pelvis
Type I correction
Acetabular fragment is rotated anteriorly and laterally to improve coverage, and bone graft is placed proximal to the overhanging acetabular bone
Type II
Iliac crest graft is inserted into the osteotomy site, which allows the fragment to be moved distally up to 2 cm to increase leg length
Type III
Require metallization of the acetabular fragment

5. Rotational Acetabular Osteotomy
The RAO is combined with a complete cut of ilium, similar to a Chiari osteotomy
Proximal ilium is shifted laterally while the distal acetabular fragment moves medially
All three variations are stabilized with internal fixation
Joint capsule remains intact

6. Rotational Acetabular Osteotomy Advantages and Disadvantages
Major correction without altering the shape of the true pelvis
Childbirth is unaffected
Disadvantages
Proximity of the osteotomy to the joint
Vascularity to the acetabulum is at risk
Fragment can be difficult to stabilize for early weight bearing
Risk of fracture into the hip joint

7. Rotational Acetabular Osteotomy Result
Good success rate
Schramm et al 20-year follow-up of 22 patients
Kaplan-Meier survivorship : 86% at 20 years, with conversion to total hip arthroplasty as the end point
Nakamura et al
80% good-to-excellent long-term result in 112 hips with minimal or no arthorosis at the time of surgery
Even advanced OA secondary to acetabular dysplasia, decrease pain at 8- to 12-year follow-ups
A minimum of 2.5mm of joint space is recommended to consider RAO
Risk factors for progressive osteoarthritis
Under correction and persistent lateralization of the femoral head

8. Triple Pelvic Osteotomy
Divide the pelvis form just proximal to the AIIS transversely to the sciatic notch
With the pubic symphysis as a hinge, distal fragment rotated anteriorly and laterally to increase femoral head coverage
Initially developed to treat persistent dislocation and subluxation in children

9. Triple Pelvic Osteotomy Advantages and Disadvantages
Key advantage
Ability to metalize the joint
Achieve an much larger correction than other innominate osteotomies
Patient with persistent subluxation and dislocation
Unlike RAO, PAO, safe for patient with open triradiate cartilage, if performed with extraperiosteal dissection of the superior pubic ramus
Disadvantage
Lacks intrinsic stability because both columns of the pelvis are disrupted
Large gaps at the osteotomy sites can result in nonunion
Alters the morphology of the true pelvis – impede childbirth

10. Triple Pelvic Osteotomy Result
Van Hellemondt et al
42 of 48 hip (88%) preserved at an average of 15 years after TPO
Merle d’Aubigne and Postel functional scores, 64% of hips were rated good to excellent
31 of 41 hips (76%) had no osteoarthritis at the time of surgery showed no OA over the 15 year interval
Peters et al
60 hips with acetabular dysplasia
49 of 50 patients (98%) were satisfied with the procedure at a mean follow-up of 9 years
16 of the 60 osteotomies (27%) were considered failures – need to convert to a total hip arthroplasty or the presence of intractable hip pain
When nonunion occurs, patients are less satisfied with the procedures

11. Chiari Pelvic Osteotomy
With advances in reorienting osteotomy, considered a salvage augmentation procedure
Indicated for a dysplastic hip with incongruity or to supplement coverage in an acetabulum with small weight-bearing zone
Anterior iliofemoral approach and involves division of the ilium from just inferior to the AIIS and curving in a semicircle to exit posteriorly through the sciatic notch

12. Chiari Pelvic Osteotomy
Osteotomy is directed approximately 15’ laterally to medially to allow medial displacement of the distal fragment
Lateralized ilium serves as the augmented bony coverage of the femoral head with the capsule interposed
In the initial series, patients were immobilized in an abduction spica cast for 4 weeks
Now accomplished with internal fixation

13. Chiari Pelvic Osteotomy Advantages and Disadvantages
Abducts the distal fragment which results in a more vertical orientation of the true acetabulum and may be beneficial in unstable hips with anterolateral impingement
Hip joint reaction forces are decreased, mechanical environment of the hip is improved because of the increased weight-bearing area and medialization of the femoral head
achieve adequate coverage of the femoral head by the iliac shelf

14. Chiari Pelvic Osteotomy Advantages and Disadvantages
Primary disadvantage
femoral head articulates with the capsule and labrum rather than the native articular cartilage
Capsule may undergo metaplasia to form fibrocartilage
Labral pathology is common
Labral tear and detachment
Abductor weakness with a persistent Trendelenburg sign can occur
Alters the true pelvis and narrows the birth canal

15. Chiari Pelvic Osteotomy Results
Positive with consistent pain improvement
Windhager et al
236 hips in 208 patients
21 of 236 hips (9%) had revision procedures (19 THA, 2 arthrodesis) at a mean 15 years after the osteotomy
Fifty-four percent of the hips had good-to-excellent result based on measures of pain, walking distance, Trendelenburg sign, range of motion
60% of patients were able to walk unlimited distance
Kotz et al
38 of 70 native hips(54%) in 66 patients were preserved at a mean follow-up of 32 years
32 hips were converted to THA, average of 26 years after the Chiari procedure

16. Summary
Pelvic osteotomies are complex, technically demanding procedures
Offer mechanical correction and symptom improvement in properly
Chiari osteotomy is reserved for
dysplastic hips with an incongruent articulation
Acetabular weight-bearing surface is exceedingly small and requires augmentation
Reorientation osteotomies
Congruent dysplasia and minimal arthrosis
PAO
Single surgical approach
Large multiplanar correction among other advantages
RAO, TPO
All of the techniques can achieve major corrections
Good results at long-term follow-up

17. Summary Disadvantages of a triple pelvic osteotomy
Instability from disruption of both columns of the pelvis
Alters true pelvis and can lead higher nonunion rate
RAO maintains the true pelvis but requires abductor muscle dissection - Prolonged limp or Trendelenburg sign
Acetabular fragment osteonecrosis and intra-articular fracture in sclerotic bone
At Boston Children’s Hospital
Adult patients with symptomatic acetabular dysplasia are managed with PAO
Skeletally immature patients are treated with a triple pelvic osteotomy
RAO has been widely used in Japan with good long-term success
Chiari pelvic osteotomy
rare patient who requires augmentation rather than reorientation of the dysplastic acetabulum

18. Summary