Survival of Birmingham Interlocking Pelvic Osteotomy

Dylan JewellCallum McBryde

John O’Hara

The Royal Orthopaedic Hospital Birmingham UK

Dysplastic Hips

The Problem

• What would you expect?

Hip Alignment~Tyre Alignment

• Normal alignment = 40,000 miles• Out of alignment = 15,000 miles• Realigned = ?30,0000 miles• If not….

Indications for surgery

• Hip dysplasia• Centre-Edge-Angle < 30°• Adult Acetabular Index >10°• Incorrect acetabular version• Interruption of the lateral Iliofemoral line

Socket - Radiological Aims• Adult acetabular index <10° • Acetabular anteversion

– Apical = 0°– Deep socket = 20° – Transverse ligament plane ~ 20°

Radiological Aims

Femur

Sourcil/weightbearing zone almost horizontal

Greater trochanter level with centre of femoral head

Round Head• Anteversion= 20°

Bone Cuts

Planning the Bone Cuts

Rotate the

X-ray !

20deg LR

2020°

A

BC

Fixator/Screw Positions

• Reflect bone cuts

Screw 1

Inserted

In IR 10 deg:

Moves to

vertical

12

CBA

==Physiological acetabular anteversion!!!

Alignment verification (all post-op patients seen January 1991-97)

Physiological apical and deep socket anteversion

Operative Details

• Ischium [lateral pos] as per Tonnis• Pubis as vertical as possible

Orthofix Screws• No 1 screw next

to QLP just above (old) TRC,

• Vertical in both planes, then adjust for antiversion

• No 2 position corrects dysplasia angle

112

Iliac Osteotomy

• 12mm saw• Cuts A,B,C,• Reflect

primary correction

A

B C

12

A

C

CB

BA

Fixation

• No 1 screw replaced with 6.5 canc, 4-hole plate upto SIJ

• Iliac crest screw

• Bone graft

Method

• First 100 patients identified• Patient demographics and outcome

determined from questionnaires, hospital notes, telephone interviews.

• Primary Outcome: Survival before Resurfacing/THR required.

• Secondary Outcomes: OHS and UCLA score

Results• 117 TPOs performed by JOH• 3 TPOs without follow-up• Mean follow-up 10 years (0 to 20)

• Mean age 31 (range 7 – 57)• Mean Acetabular Index pre-op 23• Mean Acetabular Index post-op 2• 37 Arthroplasties at mean 8 years

(95% CI 6.8 – 9.3)

Survival Curve

Age

• Our age range was 7 to 57 years• Increasing age was significantly associated

with a worse survival with arthroplasty as the end-point (p=0.02)

<20 yrs: 89%, 18 pts

<25 yrs: 76%, 32 pts

<30 yrs: 67%, 54 pts

Survival for Age of Operation

Years post operation

Survival

Secondary Outcomes

• Oxford Hip Score Median 41 (interquatile range 24-46) • UCLA: 5 (interquatile range 3-7)

UCLA1. Wholly inactive: dependent on others and can not leave house. 2. Mostly inactive: very restricted to minimum activities of daily

living. 3. Sometimes participates in mild activities, such as walking, limited

housework and limited shopping.4. Regularly participates in mild activities. 5. Sometimes participates in moderate activities such as swimming

or could do unlimited housework or shopping.6. Regularly participates in moderate activities. 7. Regularly participates in active events such as bicycling . 8. Regularly participates in active events, such as golf or bowling. 9. Sometimes participates in impact sports such as jogging, tennis,

skiing, acrobatics, ballet, heavy labour or backpacking.10. Regularly participates in impact sports.

Neonatal Septic dislocation

6yrs

13yrs

Now 20yrs FU,Excellent function,

Dance leader on a ship

Complications

• 1 PE(from contralateral leg)• 2 DVT (1 of which in non-operated leg)• 3 Non-union united after bone grafting• 1 temporary sciatic nerve palsy• 2 lateral cutaneous nerve injuries• 1 infection

Conclusions

• The Birmingham Interlocking Pelvic Osteotomy provides a valuable tool to accurately correct acetabular dysplasia,

• Preserving hip function and delaying arthroplasty surgery.

• Does labral pathology matter, once the socket is corrected??