The document outlines surgical tips for addressing ankylosing spondylitis, focusing on preoperative planning, anesthesia, positioning, and exposure techniques. It emphasizes the importance of proper diagnosis and anatomical considerations, including deformities and imaging, to ensure successful hip procedures. Key recommendations include meticulous preparation, adequate exposure and soft tissue preservation, and careful reaming and positioning of components to restore hip biomechanics.

1. Tips for THR in
Ankylosing Spondylitis
Dr Vaibhav Bagaria
Director - Orthopaedics
Sir HN Reliance Foundation Hospital
President - SICOT India
Mumbai, India
It’s Elemental! Series

2. Todays Talk
• Clinical and Radiological
• Anesthesia and Positioning
• Exposure
• Neck cut
• Acetabular Reaming
• Acetabular and Femoral component placement
• Post op and Rehab

3. Diagnosing AS

4. Clinical Exam
• Deformity: Sagittal/ Coronal and rotational
• ROM: at different joints
• Spine
• True and Apparent shortening
• Deformities are better understood clinically then
radiologically

5. Xrays - PBH
• Position of Limb: Abduction/ adduction/ Rotations
• Pelvic obliquity & SI Joint Fusion
• Femoral Canal
• Protrusio
• Quality of Fusion
• Bone quality

6. Xrays

7. CT Scan
• Bone stock
• Medial wall
• Trabecular continuity
• Femoral canal dia

8. CT Scan

9. CT - Axial

10. LS Spine Xrays

11. LS Spine Xrays
• Flexion Deformity ( decreased
Lordosis): reduce Anteversion
• Extension Deformity (
Increased Lordosis): Increase
Anteversion
• Scoliotic deformity: Close
Your Cup

12. C Spine Xrays

13. Templating

14. Templating
• Rotation and obliquity: difficult/ may not be accurate
• Femoral size: Sometimes even a Dorr C may not
accomodate smallest cemented stem
• May indicate if you need a modular implant depending on
the proximal femoral morphology

15. Pre Op

16. Anesthesia Concerns
• Anticipate difficult Spinal
• Awake Fiberoptic intubation standby
• Decreased chest expansion = Decreased Tidal Volume
• Cardiac: 30% incidence of AV block/ RBBB
• Blood product arranged

17. Blood Conservation

18. Positioning
• Lateral Decubitus with Sacral and Pubic support
• Commonest deformities are: Flexion, Abduction and
external rotation
• Bilateral deformities are not uncommon
• Adequate padding
• Multiple pillow or head rings for C Spine stiffness.

19. Before start
• Table: Should be able to Tilted; Patient strapped
• Image Intensifier
• Tranexa/ Antibiotics/ Blood reconfirmation

20. Steps
• Exposure
• Removing Head
• Preparing Acetabulum
• Preparing Femur

21. Exposure
• Release G Max
• TFL : Fractional Lengthening / W shaped release
• Identify the head acetabulum junction
• Remove labrum
• Complete visualisation of neck and soft tissue release is
the key
• Dual Approach: If the Hip is in External Rotation

22. Releasing G Max
G max Insertion

23. Capsulo - Labral
Junction

24. Removing Labrum & defining
the head/ acetabulum Jn
Head
labrum

25. Exposure
• In case of ER, the posterior structures viz capsule, rotators
are contracted
• Flexion deformity puts Sciatic Nerve at risk
• In certain case Trochanteric Osteotomy is the only way
forward
• Tilt the table for ward and towards you to expose anteriorly
and posteriorly

26. Osteotomy
• Wafer Osteotomy
• Do not damage abductor
• Does not extend to GT or acetabular wall
• Combination of Saw/Osteotome
• No Bone splintering

28. Marking Osteotomy

29. Insitu Osteotomy

30. Removing Wafer

31. Mobilising Femur

32. Reaming
• Femur is retracted anteriorly with swan neck
• 2 stein-man pin to improve exposure - complete 360
• look for circumferential labrum that gives an idea of
direction of reaming: First reamers sets the tone so be
careful
• subsequent patient reaming till floor is reached
• True floor identified as Fat pad/ unossified Lig Teres/ 2.5
mm Drill use

33. Insitu Reaming

34. Fixed Pelvic obliquity

35. Pelvic tilt

40. Cup Positioning
• Widmer et al: Cup Inclination between 40 and 42 and
combined ante version of 37
• Ranawat: For male 25 - 35; female 35 - 45
• TAL can be used as guide: parallel to TAL
• TAL also useful for inclination: Typically the posterior edge
slightly medial to TAL

41. TAL

42. The Correct coverage
At level of TAL
2 - 3 mm Postero -Superior
Uncovering
Narrow edge of bone
Anterosuperiorly
Not proud at the edge of
Anterior wall

43. Femoral Component
• Anteversion ranges from 17 - 30 degree
• Concept of combined ante version important
• As stated earlier templating may not be accurate.
• Reaming before rasping may be required in certain case
• In younger patients - preserve the bone

44. Femoral Anteversion
• Think Posterolateral
• Calcar is good clue
• Palpate the epicondyles at Knee
• Judging - Easier with the neck on

47. Limb Length
On full extension
LT at least one finger breadth below ischium

48. Closure
• Posterior structure may not be available for a tight
posterior closure
• Quadratus is a saviour: translocate a sleeve anteriorly
• Adductor tenotomy may be required postoperatively
• Suction: only if oozing is significant intro

49. Preventing Heterotropic
Ossification
• Copious Wash: At least 3 litre to clear the soft tissue of
any bone debris
• Avoid overzealous retraction; Counsel the team about
need to respect soft tissues
• Use new fresh blade for good sharp bone cuts
• No periosteal stripping
• Indomethacin 25 -75 mg if creat OK for 3 weeks.

50. Results

51. Pearls
• Good prep work up and planning
• Adequate exposure and releases
• Neck cut without splintering and damage to walls/ abductors
• Restoring biomechanics of the hip
• Identifying true acetabulum
• Restoring Acetabular centre ( correcting Protrusio)
• Correct acetabular and femoral component placement
• THINK 3D…

52. It’s Elemental! Series
vaibhavbagaria.com