Periacetabular Osteotomy: Intra-articular Work

Department of Orthopaedic surgery, University of Toronto, Toronto, Ontario, Canada,

Hip and Pelvis Clinic , Chonbuk University Hospi-tal , Jeonju, Korea .E-mail: hugo999@naver.com

Background• Periacetabular Osteotomy

- Goal : Improvement of hip biomechanics by reorienting the acetabulum

→ postpone degenerative progression

Desire of im-provement

Potential for overcorrection

Background

Complications of PAO Prevalence % AuthorsAcetabular cartilage delamination

28 of 64 hips 44% CLP

Labral injury 22% Siebenrock et alLabral tearing+/-de-generation

63 of 73 hips 86.3% Ross et al

Hypertrophied labrum

46 of 73 hips 63%

Acetabular retrover-sion

25 of 95 os-teotomies

26% Dora et al

Overcoverage of femoral head

→ iatrogenic FAI

Overlooked chondrolabral injury

(dysplasia, FAI)

Overlooked intra-articular hip inspec-tion

(early experience)

Intra-articular WorkLabral pathology

Dysplastic hip pathomorphology

FAI-pincer type FAI-cam type

Labral tissue hypertro-phy with myxoid degen-eration and/or detach-ment from the osseous acetabular rim

Undersurface labral tear-ing without hypertrophy

Labral tearing -extends perpendicular to the labral surface

Labral tearing- at the transition(fibrous cartiliginous labrum/ar-ticular hyaline cartilage) zone perpendicular to the articular surface

Labral injury alone could generate sufficient pain to re-quire intervention

The positive outcome- pain relief after debridement and/or fixation of labral tears,

The acetabular labrum - a triangular structure with a basilar attachment to the osseous acetabular rim - a capsular insertion along the external surface - a free intra articular apical margin

Intra-articular WorkLabral pathology

1. Anterior hip arthrotomy

Modified Smith-Petersen approach used for Bernese PAO 2. Indirect head of rectus femoris is tagged and mobilized for

improved view3. Capsular incision along the long axis of the femoral neck →

AP direction at the level of acetabular rim 4. Simple debridement5. Labral repair using suture anchor technique is used for

labral detachment at the extra-articular osseous inser-tion

6. Labral detachment → Preservation of the blood supply

Labral repair with suture anchor : TOC for unstable hypertrophied labrum

Intra-articular WorkLabral pathology

Intra-articular WorkLabral pathology

Labral refixation with suture an-

chors fixed to new acetabular rim

Labral takedown and Rim resection

Correction achieved

Intra-articular WorkChondral pathology

• Chondral lesion - Location : anterior and superolateral aspect of acetabulum - Size : 171.7 mm2

• Chondral lesion– Chondromalacic, cleavage, or debonding injury

Intra-articular WorkChondral pathology

• The natural history of these lesion and whether chondral le-sions are independent source of pain have not been deter-mined.

• Nascent chondral lesions identified at the time of PAO rep-resent an opportunity to alter the degenerative cas-cade.

Intra-articular WorkChondral pathology

In contrast with labral pathology, preOP diagnosis of chondral injury has implications for preOP planning

- Hip MR Arthrography : mainstay of soft-tissue hip diag-nostic imaging

(Specificity ↑, Sensitivity ↓)

Intra-articular WorkChondral pathology

1. Inspection : Patient’s specific hip pathophysiology

Diagnostic imaging

2. Rim resectionAmount of rim resection to properly address the

chondral lesion

Staged surgical dislocation → PAOObtain consent for a possible simultaneous

PAO

Intra-articular WorkChondral pathology

Femoral head-neck offset• More than 90% of patients treated with PAO require some

degree of femoral head-neck offset correction → Intraoperative C-arm fluoroscopy (False profile view, Dynamic impingement view)

Intended ac-etabular correc-

tionFemoral head-

neck offsetPotential exac-erbation of FAI

Assess

Femoral head-neck offset

Cam lesion on femoral head-neck

junction

burr allows ade-quate restoration

of the femoral head-neck offset

Adequate offset achieved