THA after Chiari osteotomy: THA after Chiari osteotomy: Intraoperative complications and Intraoperative complications and

behaviour of cup fixation in 24 behaviour of cup fixation in 24 casescases

Migaud H., Beniluz J., Gougeon F., Pinoit Y., Migaud H., Beniluz J., Gougeon F., Pinoit Y., Besson A., Duquennoy A.Besson A., Duquennoy A.

Department of Orthopaedic Surgery, Department of Orthopaedic Surgery, University Hospital of Lille, France.University Hospital of Lille, France.

Introduction : Introduction :

• Conservative surgery to Conservative surgery to prevent or stabilize prevent or stabilize arthrosis without arthrosis without worsening the result of a worsening the result of a subsequent THR :subsequent THR :– Problems related to THR after Problems related to THR after

proximal osteotomy of the proximal osteotomy of the femurfemur

– Few papers related to the Few papers related to the THR after pelvic osteotomiesTHR after pelvic osteotomies

PETERS CJ : J Arthroplasty, 2001

13 hips : worse result THR after failed TIO.Fw-up 36 m.

HASHEMI-N A : J Arthroplasty, 2002

28 hips : THR after Chiari results = to primary THR, but less pelvic bone graftingFw-up 60 m.

PARVIZI J :CORR, 2004

41hips : THR after PAOcaution to acetabular retroversion (23/41)Fw-up 6,9 years

Introduction : Purpose of the studyIntroduction : Purpose of the study

• Modifications of the Modifications of the acetabulum related to acetabulum related to the Chiari osteotomythe Chiari osteotomy– Medial displacementMedial displacement– EnlargementEnlargement– Vascular and bone supportVascular and bone support

• Concerns about Concerns about 1) long term fixation of the cup1) long term fixation of the cup

2) Functional result2) Functional result

3) Intraoperative complications3) Intraoperative complications

Patients and MethodsPatients and Methods

• 204 Chiari osteotomies (1975-2000) 204 Chiari osteotomies (1975-2000) 29 hips conversed to THR29 hips conversed to THR

• 24 THR with a follow-up > 5 years24 THR with a follow-up > 5 years were were assessed retrospectively assessed retrospectively

• 23 patients (20 F, 3 M)23 patients (20 F, 3 M)• Mean age at the time of conversion = Mean age at the time of conversion = 50 y. 50 y.

(range, 36-63)(range, 36-63)

Patients and Methods (n = 24)Patients and Methods (n = 24)

• Chiari were “dome Chiari were “dome shaped” and performed shaped” and performed through a Smith through a Smith PetersenPetersen

• Fixed with lag screwsFixed with lag screws• Indication for Chiari : Indication for Chiari :

– Dysplasia (15/24 CE Dysplasia (15/24 CE << 5°) 5°)– Arthrosis (20/24 had joint Arthrosis (20/24 had joint

space narrowing)space narrowing)

Patients and Methods (n = 24)Patients and Methods (n = 24)

• Conversion after a mean follow-Conversion after a mean follow-up of up of 8 y.8 y. (range 1-24 y.)(range 1-24 y.)

• All THR through a Postero-All THR through a Postero-Lateral approachLateral approach

• No patient lost for follow-upNo patient lost for follow-up• Mean THR follow-up = Mean THR follow-up = 10 +/- 3 y. 10 +/- 3 y.

(range, 6-15)(range, 6-15)

Components (n = 24)Components (n = 24)

Cemented Cementless

Stems 19 5Muller/Kerboull CLS/Alloclassic

Cups 3Full Poly

21Harris/Allofit

Functional Results (n = 24, Fw-up = 10y.)Functional Results (n = 24, Fw-up = 10y.)

• Favorable functional Favorable functional resultsresults

• All the walking scores All the walking scores at follow-up at follow-up >> 5 points 5 points

11,7

17

0

2

4

6

8

10

12

14

16

18

Before THR Follow-up

Merle d’Aubigné Hip rating

Functional Results (n = 24)Functional Results (n = 24)

• No postoperative No postoperative dislocation despite dislocation despite medial displacement medial displacement by Chiari osteotomyby Chiari osteotomy

• Post-operative LimpPost-operative Limp

14

0

2

4

6

8

10

12

14

16

18

Before THR Post THR

Number of Hips with a Trendelenburg

Results: Intraoperative complications Results: Intraoperative complications

• No neurovascular injuryNo neurovascular injury• Screw removal necessary in 9 Screw removal necessary in 9

cases cases – To avoid contact between screws To avoid contact between screws

used for Chiari and cup fixation or used for Chiari and cup fixation or to easto easee bone preparation bone preparation

– Difficult in 2 casesDifficult in 2 cases (the distal part (the distal part of the screw was broken and left in of the screw was broken and left in place)place)

Results: Cup fixation and bone coverageResults: Cup fixation and bone coverage

• Three cases of lack in Three cases of lack in bone coverage > 20% of bone coverage > 20% of the cup (all posterior and the cup (all posterior and superior)superior)– 1 treated by deepening1 treated by deepening– 1 treated by few bone chips1 treated by few bone chips– 1 treated by autograft1 treated by autograft

• One additional case of One additional case of autograft to correctly autograft to correctly locate the hip center in a locate the hip center in a dislocated hipdislocated hip

Results: Cup fixation and ImpingementResults: Cup fixation and Impingement

• Anterior impingement Anterior impingement with the Major with the Major trochanter in 2 cases trochanter in 2 cases (excessive anterior (excessive anterior coverage)coverage)

• Bone resection Bone resection required on the pelvic required on the pelvic bone in 2 casesbone in 2 cases

Results: Cup orientationResults: Cup orientation

• Mean frontal angle = Mean frontal angle = 43° +/-9° [20° to 58°] 43° +/-9° [20° to 58°]

• 3 cups had inclination 3 cups had inclination < 35° and 2 over 55°< 35° and 2 over 55°

• 4 hips had M-M 4 hips had M-M bearings (in 28 mm) bearings (in 28 mm) without impingementwithout impingement

Results: Cup FixationResults: Cup Fixation

• None of the cemented cups None of the cemented cups and 18/21 cementless cups and 18/21 cementless cups = free of osteolysis, no = free of osteolysis, no radiolucencies, no migrationradiolucencies, no migration

• 3 of the cementless cups 3 of the cementless cups had radiolucencies (had radiolucencies (22 of of them had progressive them had progressive lucencies and severe lucencies and severe osteolysis osteolysis reoperation)reoperation) 10 y.10 y. #1#1

Results: ReoperationResults: Reoperation

#1#1

#1#1

#1 4y. Post

• Only 2 patients had revision Only 2 patients had revision surgery (osteolysis, wear)surgery (osteolysis, wear)

• No revision was related to No revision was related to the prior osteotomy :the prior osteotomy :

• #1#1 (@ 5y.) osteolysis + cup (@ 5y.) osteolysis + cup loosening (osteolysis) = loosening (osteolysis) = – Intra-articular migration of Intra-articular migration of

metallic debris from the coating metallic debris from the coating (Fibermesh)(Fibermesh)

– Bone grafting + cup revisionBone grafting + cup revision

Results: ReoperationResults: Reoperation

• #2#2 (@15y.) Osteolysis + (@15y.) Osteolysis + loosening cup + femur = loosening cup + femur = – Severe polyethylene wearSevere polyethylene wear– Poor fixation of the insert in Poor fixation of the insert in

the metallic shellthe metallic shell– Overweight (BMI = 31)Overweight (BMI = 31)– Pelvic grafting with cup and Pelvic grafting with cup and

femoral revision femoral revision (cementless locked stem)(cementless locked stem)

#2#2

#2#2Post-op

#2 1y. Post

Conclusions (1)Conclusions (1)

• Conversion of a Chiari to Conversion of a Chiari to THR = simple procedureTHR = simple procedure

• Low rate of acetabular Low rate of acetabular augmentation (bone grafting) augmentation (bone grafting) despite severe dysplasia despite severe dysplasia before the Chiari)before the Chiari)

• Attention should be paid to Attention should be paid to bone-to-bone impingement if bone-to-bone impingement if excessive bone coverageexcessive bone coverage

Conclusions (2)Conclusions (2)• Chiari osteotomy : Chiari osteotomy : 1) does not modifiy 1) does not modifiy

rehabilitation program rehabilitation program versus with primary THRversus with primary THR

2) does not worsen cup 2) does not worsen cup fixation = only 2 revisions fixation = only 2 revisions but none related to the but none related to the prior osteotomyprior osteotomy

3) gives the opportunity to 3) gives the opportunity to insert larger cups insert larger cups (resistance to wear)(resistance to wear)

Primary THRTHR post Chiari

Thank you for your attentionThank you for your attention