Fixation in osteoporotic bone. Jeppe Barckman Ortopædkirugisk afd. Aarhus Universitetshospital

Transcription

1 Fixation in osteoporotic bone Jeppe Barckman Ortopædkirugisk afd. Aarhus Universitetshospital

2 Objective Highlight current principles of fixation for osteoporotic fractures

3 Woman 75 year Who to fix?

4 The problem 30-50% of postmenopausal women experience fracture(s) related to osteoporosis Epstein S, Aging 2000 Eastell R, Proc Nutr Soc 2002

5 The problem Nonunion & implant failure: 2-10% Malunion 4-40% Reoperations 3-23% Bohlofner B, JOT 1996 Stover M, Injury 2001 Syed AA, Injury 2004

6 Bone quality

7 8.5% decrease in compressive bone strength per decade McCalden R, JBJS 1997

8 Screw pullout strength vs BMD Reitman CA, J Spinal Disord Tech 2004

9 The dual bone problem Reduced tolerance for compressive loads Reduced screw purchase in bone

10 Therefore No need for stronger implants, but better bone fixation! The common mode of failure of internal fixation in osteoporotic Who? bone is bone failure rather than implant breakage

11 In good bone Absolute stability - loadsharing Anatomic reduction Stable fixation Direct bone healing Won t work in osteoporosis!

12 In osteopenic bone Relative stability - loadbearing

13 IM nails Offer both biomechanical and biological advantages Loadbearing implant Less invasive applications

14 IM nails problems in osteopenic bone Locking Anatomic mismatch - wide medullary canal

15 Use multiple locking screws

16 Angular stable locking screws?

17 Condyle screw

18 Anatomic mismatch Solve with: Poller screws Open reduction prior to nailing

19 Anatomic mismatch Solve with: Poller screws Open reduction prior to nailing

20 Plating in osteoporosis Relative stability Less invasive techniques

21 Angular stable plates

22 Pullout of regular screws by bending load

23 Higher resistance against bending load Larger resistant area

24 Increased plate length decrease Working pullout forces length Screw Density 0.5 Screw Density 0 Screw Density 0.75 Fracture Length Length

25 Increased plate length decrease Working pullout forces length Screw Density 0.5 Screw Density 0 Screw Density 0.75 Fracture Length Length

26 Increased plate length decrease Working pullout forces length Screw Density 0.5 Screw Density 0 Screw Density 0.75 Fracture Length Length

27 Increased plate length decrease Working pullout forces length Screw Density 0.5 Screw Density 0 Increased plate length decrease pullout forces Fracture Length Length Screw Density 0.75

28 Increased working length decrease strain Increased plate length decrease Working pullout forces length on implant Screw Density 0.5 Screw Density 0 Increased plate length decrease pullout forces Fracture Length Length Screw Density 0.75

29 Increased working length decrease strain Increased plate length decrease Working pullout forces length on implant Screw Density 0.5 Screw Density 0 Increased plate length decrease pullout forces Fracture Length Length Screw Density 0.75

30 Increased plate length decrease Working pullout forces length Screw Density 0.5 Screw Density 0 Screw Density 0.75 Fracture Length Length

31 Osteoporose: bikortikale skruer 40

32 Screw augmentation PMMA Disadvantages: Heat formation, non- resorbability, may inhibit fx healing Advantages: Mechanically strong, easily available

33 Screw augmentation Injectable calcium phosphate cements increase pullout strength Larsson S, J Biomech 2012

34 Allograft

35 External fixation in osteoporosis Conventional frames depend on screw purchase in bone for stability Excellent for initial fx treatment Increasing complication rates with time in frame

36 Ring fixators Ring fixators utilize numerous fine wires and screws Improved biomechanics decrease shear loads in bone/ screw interface But problem with loosening of screw and pin-infection

37 Alternative osteosynthesis

38 61-years old women

39 61-years old women

40 Lateral percutaneous fixation

41 Difficult problem 50 year women Multi morbid Sever osteoporosis Not cooperative for non-weight bearing.

42 Difficult problem What to do

43 Calcaneo-talo-tibial nail

44 Avoid future fractures Low energy fracture Women > 50 year Men > 60 year DEXA Calicium + D-vit

45 Take home messages Fixation in osteoporotic bone Absolute stability should not be strived for Use mini- invasive surgical techniques whenever possible Realignment of mechanical axis crucial Favour IMNs!

46 Take home messages Fixation in osteoporotic bone In IM nailing stability is maximized by Using blocking screws Increased number of locking screws

47 Take home messages Fixation in osteoporotic bone Maximized mechanical stability in plating can be obtained by Angular stability Long plates Screw augmentation Increased plate working length protects implant

48 Tak