Valgus or abduction osteotomy for Non union Femur

Non union Femur can be challenging especially in younger patients in whom head should be preserved whenever possible. This presentation gives an insight on tips, tricks and traps of performing Valgus or abduction osteotomy.

1. Dr Vaibhav Bagaria Director - Dept of Orthopaedics Sir HN Reliance Foundation Hospital President - SICOT India Mumbai, India VALGUS OSTEOTOMY FOR NON UNION NECK FEMUR It’s Elemental! Series

2. Todays Talk Understanding the Principle Preoperative Planning Execution Case example Drawbacks and Alternatives

3. Why NOF are unique? Injury to Capsular arterial blood supply Tamponade effect Synovial fluid Interface Absence of cambium layer of the periosteum

4. Winning Combination Biology Bone Quality Biomechanics

5. Not all # config the same Non union Rates can be as high as 30%

6. Pauwel ’ s Concept Pauwel pointed out that the resultant force across the hip was due to the body weight and the muscular force of the abductors. Force was directed approximately 16 degrees from the vertical plane and approximately 25 degrees from the anatomical axis of the Femur

7. The Concept Typical femoral neck non union was oriented vertically and thus subject to significant shear force produced by the normal hip joint load.

8. The Concept He proposed a valgus osteotomy to reorient the non union so that the shear forces are converted into compressive forces.

9. Pauwels Principle Final fracture Inclination of 30 degree or less to convert the shearing force into the compressive forces Proposed by Pauwel, Popularised by Muller!

10. Principle Shear Force to Compressive Force =

11. Pre operative planning Determining the level of osteotomy Size of the bone wedge to be removed Type of implant to be used Position of the seating Chisel/ DHS Screw

12. Calculating the size of wedge Pauwel technique refined by Muller Goal is to have Pauwels angle of 30 degree post operatively Preoperative Pauwels angle - desired Pauwels angle = repositioning angle The placement of chisel/ screw plate construct should be in manner that the side plate makes and angle corresponding to repositioning angle.

13. Blade or Screw placement Direction of the screw or blade should be in the inferior part of the head of femur in AP and in centre in the lateral position Osteotomy site should be at least 1.5 cm distal to entry point of Chisel or the screw. This would avoid fracture of the lateral cortex while passing the screw.

14. Osteotomy Proximal limb of the osteotomy should be perpendicular to the long axis of the femur Distal limb should be marked at the desired angle and wedge removed. Location of the wedge on an AP view is indicator of how much length would be gained post osteotomy Apex of the osteotomy should be medial to anatomical axis as on compressing the two fragments will impact better.

15. Choice of implant Blade plate or DHS Blade plate: technically demanding but: Small foot print Remove less bone Better Rotational Stability

16. Example Suppose the original Pauwels angle is 60 degrees Desired angle = 30 degree Repositioning angle = original - desired = 60 - 30 = 30 degrees so a 30 degree wedge be removed and the blade/Screw construct be placed in manner that allows the plate to make an angle of 30 degree with shaft axis So for a fix angle blade plate ( 120 degrees) the chisel be placed at 120 - 30 = 90 degree and for DHS plate ( 135 degree plate) the screw is inserted at 135 - 30 = 105 degrees.

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33. Follow Up

34. Pearl 1

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37. Pearl 4 Severely Osteoporotic or neck respiration: Think Fibula

38. Results

39. Drawbacks Medializes the Shaft Excessive Valgus - > AVN ( Increase Joint Reaction Force/ kinking of posterior reticular vessels) Gait disturbances and limp Reduced femoral offset Possible Knee joint Malalignment Future THR??

40. Alternatives Vascularised fibula? ?? Muscle Pedicle Graft ?? Girdle stone Osteotomies : ?? 1.McMurray ’ s 2.Schanz 3. Dickson ’ s 4. Pauwell ’ s Y Replacement: ?? Bipolar ?? THR ?? Uncemented/Cemented

41. Take Home Message Rewarding Surgery Acts by converting shear forces into compressive forces Careful prep planning and wedge calculation is the key Avoid excessive Valgisation Think Biology Augmentation when in doubt

42. BOS Hip Preservation Course 2017