Pathophysiology and Biomechanics of fracture healing. A really biased view by a convert!!

1. Dr L.Prakash M.S., MCh. (liverpool)

2. Man doesn’t heal fractures
Nature does
 What happens if you don’t treat fractures??
 What happens to animals with fractures??
 When was the first metal put in the human
body?
 Why occasionaly fractures don’t heal despite
multiple surgeries?
 Is there any absolute indication for internal
fixation??
 These and other Questions often plague us
orthopaedic surgeons

3. Questions Questions Questions
 Wild animals in the jungles don’t go to a bone setter or
an orthopaedic surgeon. Yet their fractures heal most
often.
 Animals with fractures know that the broken limb is to
be kept immobile until pain subsides.
 They then gradually return to function after the
fracture heals.

4. An untreated horse, back to walking in 2
months

5. Dogs don’t go to orthopaedic surgeons
This is an Irish setter with a bad malunion

6. There he is after six months

7. Untreated fractures invariably heal

8. It may heal with shortening

9. It may heal with over riding

10. But it heals neverthelesss

11. When was the first metal implanted into the
human bone????

12. An Egyptian mummy with a screw like device transfixing the knee,
is the oldest known case of a metal implant in the bone.

13. The mummy story
 In 1971, the Rosicrucian Museum in California acquired a
sealed ancient Egyptian coffin containing the well-
preserved mummy of a high status Egyptian male. More
than two decades later, a team of scientists made a
shocking discovery – the mummy displayed evidence of an
advanced surgical procedure carried out nearly 2,600 years
ago.
 Inside the mummy’s left knee was a 9-inch metal
orthopaedic pin that had been inserted with such advanced
biomechanical principles, that initially scientists could not
distinguish it from a modern-day procedure

14. So man has been trying to play god for over two
thousand years!!

15. And now he thinks that he is probably
better than GOD

16. But the worst by nature can certainly not
compete with the worst by man

17. But the worst by nature can certainly not
compete with the worst by man

18. But the worst by nature can certainly not
compete with the worst by man

19. But the worst by nature can certainly not
compete with the worst by man

20. But the worst by nature can certainly not
compete with the worst by man

21. To treat fractures properly, we need to
understand
 Biology of normal fracture healing
 Blood supply to the bone
 Role of immobilisation
 Role of micromotion
 Role of mobilisation
 The difference between ANATOMICAL and
FUNCTIONAL reduction of a fracture.

22. Blood supply to the bone
 Is either medullary or cortical
 Nutrient artery perfuses the medulla
 Periosteal vessels supply cortical bone.

23. When a fracture occurs:
 Periosteum is torn
 Medullary integrity is disturbed.
 A fracture haematoma collects and stops when the
internal pressure equals systolic BP

24. Now starts the fracture healing
 Haematoma resolution
 Deposition of soft callus
 Maturation of the callus
 Calcification or hard callus
 Consolidation
 Remodelling

25. This pattern is universal with all fractures

26. All fractures more or less follows the rule of
three.
 No fracture heals before three weeks
 Adults take twice the time as adolescents
 Children take half the time as adolescents
 Lower limb fractures take twice the time as upper limb
fractures
 Open fractures take twice or more time as closed
fractures.

27. Thus all fractures will unite if you give it
sufficient time.
 The only question is whether it will unite in an
anatomical position or not.

28. It is essential to know the
difference
 Union in anatomical position versus healing in
functional position.

29. Anatomical position:
 No overriding
 No rotation
 No angulation
 Accurate repositioning of the fractured ends.

30. Functional position
 Irrespective of what the X-ray shows, the person is able
to use the limb to full function after fracture healing

31. Fracture haematoma is like colostrum for a
new born.
 Periostal integrity is essential for microvascular
transport of callus and other factors stimulating bone
healing
 We surgeons open the fracture converting a simple one
to COMPOUND.
 We then suck away all the valuable haematoma.

32. What good would a haematoma do
inside a suction bottle??

33. We then cut the periosteum,
thereby disturbing the blood
supply. We dill holes right across
disturbing the medullary supply
Else we ream the medulla totally
removing the valuable marrow

34. IS THERE ANY consequence OTHER
THAN THIS??

35. Or this

36. Or these

37. And these

38. Or more of these

39.  In surgically fixing a fracture we DELAY nature’s
attempts at fracture healing
 We deliberately convert a simple (closed) fracture to
compound (open) fracture
 All internally fixed fractures will certainly heal
SLOWER than the one left alone

40. An infected non union for a surgeon is just a
statistic
 But for the patient it is:
 A lost job
 A missed examination
 A ruined career
 A groom or boy being denied marriage
 The whole household in debts for years
 Misery misery misery
 For him it is 100% disaster, multiple surgeries,
prolonged morbidity, and Hell of a life

41. A fractured limb can be encased in a rigid
plaster but the bone inside cannot.

42. A fractured limb can be encased in a rigid
plaster but the bone inside cannot.

43. Micromotion at the fracture site
has a very important role in bone
healing.
Minute movements of the fracture
ends causes callus to be thrown at
the site

44.  A cyclically loaded rotatory micro-motion will cause
lot of callus but the ends don’t get a chance to unite.
This causes the elephant foot non union.

45.  An angular micromotion produces atrophic
of horse hoof non union

46. Minimal compression distraction
produces healthy callus!!

47. A nail providing this situation clearly
throws up a lot of healthy callus

48. Lanyon and Rubin ( 1984) demonstrated that
cyclic axial loading increases callus formation and
maintained good bone mass.
Woolf and Wright (1981) and Goodship &
Kenwright (1985) demonstrated shortened
fracture healing times in animals, with
intermittent cyclic axial dynamization.

49. So it can be logically concluded that fractures can
be treated by :
 Rigid immobilisation with compression or locking
plates.
 Semi rigid immobilization with nails, made more rigid
by locking.
 Non rigid immobilisation by plasters or splints
 Rigid immobilisation by external fixators
 Dynamic immobilisation by traction or Flexible
external fixators.

50. Rigid versus Non rigid
immobilisation
 The Synthes group led by Muller, Algover, and
Willeneggar, advocated compression plating and
described PRIMARY BONE HEALING

51. Primary bone healing
 No external callus is visible
 Patient returns to function immediately

52. Primary bone healing
 X-rays look Fantastic
 But: There is no way to tell when the fracture has
united.

53. Primary bone healing
 In many cases the fracture has fallen apart when the
plate was removed after eight to nine months.
 This prompted the Synthes group to issued a guideline
that the plate should not be removed before 18 to 24
months or never at all

54. What actually happens with
COMPRESSION PLATING?
 The plate assumes the function of the bone, bypassing
the forces, which now travel through it.
 Surgical trauma, periosteal stripping and medullary
drilling compromises the vascularity.
 All plated fractures heal considerably slower than
conservative

55. What actually happens with
COMPRESSION PLATING?
 There is a constant race between bone healing and
implant stresses.
 If the bone heals first, as it happens in majority of
cases, all is well!!
 Else the plate will break!!

56. What actually happens with Intramedullary
unlocked nails??
 Advantage of Good vertical compression without
locking.
 Gives good resistance in lateral shifts and angular
stresses
 BUT BUT BUT….
 Reaming of the medulla screws up the blood supply
 Gives poor resistance to rotatory stresses.

57. What actually happens with Intramedullary
locked nails??
 Good compression and rigid fixation possible
 Distinct disadvantage is that compressive
micromotion is lost.
 May need dynamisation at a later stage by removal of
some locking screws.

58. What happens with rigid external fixators,
both static and dynamic??
 Uniaxial fixators have a very high shear stiffness in the
plane of pins but low in 90 degree shift.
 Biaxial fixators have high shear stiffness in both lateral
bending and torsion.
 During linear compression of these fixators, plastic
deformation of the pins is usually observed.

59. The magic of original Ilizarov
 Original
 Original
 Original

60. This is not an Ilizarov assembly
See the Shanz pins sticking out!!!

61. This is not an Ilizarov assembly

62. This is not an Ilizarov assembly

63. This is not an Ilizarov assembly
either!!!

64. In my opinion there are only three
MAGIC COMPONENTS in Ilizarov
 Tensioning of wires
 Corticotomy
 Controlled distraction

65. A 1.8 mm K wire, tensioned at 80
kg is stronger than a 7mm
Stienman pin and yet inherently
elastic compared to a stiff pin.

66. Originally G A Ilizarov never used
anything except pins. Thin pins,
thicker pins, but all pins capable of
being tensioned.

67. By substituting Shanz screws for K-
wires, we loose the Magical
advantage of INHERENT
DYNAMISM

68. A shanz pin will exhibit ductile behaviour, and axial
loading often produces pin deformation

69. Corticotomy is just that...
Cutting the cortex alone without
interfering with the medulla

70. Technique

71. The third magic of Llizarov
 Controlled Distraction, both for bone transport and
elongation.
 Fortunately, this is something everyone knows and
follows.

72. If we do not respect the original
concepts of the designer, the
results will decidedly be inferior!!

73. So what can we conclude from this
talk?
 Have I advocated a complete ban on internal fixations
in fractures??
 Do I recommend conservative management in all
cases??
 Do I recommend Ilizarov in most trauma cases?

74. No,
No,
No

75. Internal fixations do have a role, but it is
limited
Ilizarov fixations too should be handled
similarly and the correct patient and
fracture is to be chosen. But please avoid
stiff Shanz pins in the Ilizarov system.

76. In intraarticular fractures with or
without dislocation Ilizarov gives
distinctly better results. A
ligamentotaxis usually restores the
joint.
A good percentage of fractures can well
be treated conservatively.

77. Example of Ligamentotaxis

78. We must not forget skeletal
traction, Fisk traction, gravity
methods, plaster
applications, and splints!!
These too have an important
role in selected cases.

79. And in conclusion:
 Hippocrates has said it .. “Do no harm”
 Don’t fight nature, assist natural processes.
 Think very carefully before converting any simple
fracture into a compound fracture

80. Thank You