Principles of Fracture Management 1 Flashcards
1
Q
What are the 3 best ways of achieving stability?
A
–Non-invasive
–Minimally-invasive, or
–Open techniques
2
Q
What are the 9 ways of classifying a fracture?
A
- Which Bone e.g. Tibia +/- Fibula
- Position within bone e.g. Proximal third of Diaphysis
- Fracture Pattern e.g. long oblique
- Open / Closed e.g. is there an open wound?
- Extra features e.g. Articular / Fissure lines
- Over-riding e.g. Moderate over-riding
- Displacement of distal segment relative to proximal
- Degree of malalignment (only if minimally displaced)
- Soft tissue swelling
3
Q
Which 2 orthogonal views do we take to evaluate a fracture?
A
Craniocaudal & mediolateral
Dorsopalmar & mediolateral
4
Q
What is the issue here?
A
Tibial fracture
5
Q
What are the different anatomical locations of a bone?
A
Epiphysis - articular
Physis = growth plate
Metaphysis – wider bone
Diaphysis – 80%
6
Q
What is a simple fracture?
A
Only 1 fracture line i.e. bone split into 2 pieces
7
Q
What are the 3 types of simple fracture?
A
- Transverse
- Olique
- Spiral
8
Q
What is a transverse fracture?
A
- Fracture ≤ 30 degrees perpendicular to long axis of bone
- Inter-digitating i.e. fracture surface irregular with spikes and depressions on both ends of fractured bone that “interdigitate” with each other
9
Q
Label this image showing the fracture types
A
Yellow – long axis of bone
Red – perpendicular to the long axis = transverse fracture or 30 degrees off
Green – oblique more than 30 degrees off the red line
10
Q
Discuss this x ray
A
Transverse Fracture – interdigitating where bits of bones stick into each other. Straight across the bone
11
Q
What type of fracture is this?
A
Transverse Interdigitating – average pattern is straight across. Interdigiting – more stable! Stable to rotation
12
Q
What is an interdigiting fracture stable to?
A
Rotation
13
Q
What is an oblique fracture?
A
Fracture line > 30 perpendicular to long axis of bone
14
Q
What is a spiral fracture?
A
Curves/spirals around the bone
15
Q
At what angle is this oblique fracture?
A
50-60 degrees
16
Q
What angle is this fracture at?
A
40-50 degrees
17
Q
What type of fracture is this?
A
Spiral fracture
18
Q
Define spiral fracture
A
Long oblique fracture that curves / spirals around the bone
19
Q
How do spiral fractures come about?
A
20
Q
What could a spiral fracture mean?
A
May mean there is a underlying bone pathology
21
Q
What is a comminuted fracture?
A
- More than one fracture line that connect
- May be multiple joining fractures
- End result = 3 or more pieces of bone
22
Q
What is going on here?
A
Comminuted fracture – left 6 pieces of bone. Moderately to highly comminuted.
23
Q
What usually caues a comminutted fracture?
A
High impact to smash the bones
24
Q
What is this?
A
Comminuted – radius fracture with adjacent ulnar.
25
What is a segmental fracture?
A rare type of comminuted fracture.
## Footnote
- 2 or more fracture lines that do not connect
- Each bone is a complete piece of cortex
- Result = 3 or more intact pieces of bone
- Wedge / Butterfly
26
What is this fracture?
Segmental
27
What is this?
Avulsion fracture
28
What is an avulsion fracture? How does it normally happen?
* Apophyseal bone avulsed - insertion point of tendon or ligament
* Usually puppies kittens landing with leg extending, will pull off the tibial tuberosity. Typical in staffies. “Landing” injury from a short height
* Open growth plate = physis = weaker than bone
29
What type of fractures happen in the skeletally immature?
Physeal fracture
30
What is the classification for physeal fractures?
Salter Harris, types 1 to 5
31
What is type 1 of the salter harris physeal frature classification?
A complete physeal feacture with or without displacement
32
What is type 2 of the salter harris physeal frature classification?
A physeal fracture wthat extends through the metaphysis, producing a chip fracture of the metaphysis (which may be very small)
33
What is type 3 of the salter harris physeal frature classification?
A physeal fracture that extends through the epiphysis
34
What is type 4 of the salter harris physeal frature classification?
A physeal fracture plus epiphyseal and metaphyseal fractures
35
What is type 5 of the salter harris physeal frature classification?
A compression fracture of the growth plate
36
What are the 5 primary physiologic forces acting on a normal bone?
Axial compression
Bending
Shear
Torsion
Tension
37
Label these primary physiological forces acting on the bone
1. Axial compression
2. Bending
3. Shear
4. Torsion
5. Tension
38
Define axial compression
Main force of weight bearing
39
Define bending (the force not bending over you sarcastic bitches)
Compresive force eccentrically loading of bone
40
Define shear
Sideways bone displacement
41
Define torsion
Axial rotation/twisting
42
Define tension
Only apples at point of insertion of ligaments (apophysis) NOT DIAPHYSEAL BONE
43
What do external forces produce on bone/fractures?
Internal stresses/strains
44
Label the coloured arrows as forces.
Red - shear
Yellow - torsion (axial rotation)
Green - bending
Blue - compression
Black - avulsion
45
What is tension avulsion?
EXTERNAL FORCE
Occurs when ligaments or tendons apply a distractive force, eg the patella tendon on the tibial tuberosity
46
Give 2 locations of tension avulson (3)
* Gluteal muscles, greater trochanter
* Patella tendon on the tibial tuberosity Triceps, olecranon of ulna
* Common calcaneal tendon, calcaneous
47
A) What is axial compression?
B) Where is it good?
C) What does an oblique force produce?
A) Produces a compressive force
B) If fracture is transverse or fragment ends interdigitate
C) On an oblique fracture produces a shear force --\> over-riding and collapse of fracture e.g. if oblique or comminuted
48
Is the compression of a transverse fracture stable?
Yes
49
What does compression occur in oblique/sprial fracture?
Fracture ends shear over each other
50
What are the two sides to the bbone when axial compression creates a bending force within bone?
Compression and tension sides
51
What forces do these two arrows resemble?
Green - tension
Blue compresion
52
What are the force surfaces on the left and right of this bone?
Left - tension
Right - Compression and bending
53
Where do you put a plate for a transverse fracture?
On bending/compression side
54
For transverse fracture with intact trans conrtex, where are plates put?
Plates placed on the tension side (opposite to compression)
STRONG
Very unlikely to fail early
55
Where are the tension surfaces accessed surgically for:
A) Humerus?
B) Radius?
C) Femur?
D) Tibia?
A) Lateral and cranil
B) Cranial and medial
C) Lateral
D) Medial and cranial
56
What is shear force?
Force that displaces bone perpendicular
57
What is a rotating or torsion force?
Twisting along long axis of the bone
58
What are the 4 long bone forces?
* Shear
* Torsion (axial rotation)
* Bending
* Compression
59
What is the tendon/ligament force?
Avulsion
60
What will the fixation of a fracture depend on?
- Fracture type
- Patient factors (biological healing score)
- Equipment available
- Surgeon experience / confidence with fixation method
61
Which two fracture types are unstable to all forces?
Comminuted or non-reconstructed
62
What is the strain theory?
* Measurement of the strain (% movement) at the fracture. How much the fracture is moving.
* Strain is a measure of the distance moved by the fracture ends as the animal weight bears
* Different healing tissue types can cope with different degrees of deformation
* An indication of the degree of stability required of the implants
* Amount of movement divided by original fracture length
* Bone can only tolerate so much movement before it fails to heal
63
What are the fractured bone phases of healing tissue?
* Fracture haematoma
* Granulation
* Fibrous
* Cartilage
* Bone
64
Define strain
% tissue deformation relative to fracture gap
65
Name 2 things strain is reduced by (3)
* Increasing the distance between the fracture ends, i.E. Big fracture gap or resorbing some of the bone as occurs early in fracture
* Reducing movement = fracture repair and stabilising
* Reducing movement = as callus develops
66
What is the equation for strain?
Change in length/original length
67
What is the % deformation to rupture in granulation tissue?
100%
68
What is the % deformation to rupture in fibrous connective tissue?
20%
69
What is the % deformation to rupture in fibrocartilage?
10%
70
What is the % deformation to rupture in woven lamellar bone?
71
What is gap strain?
Measure of fracture gap movement / stability
72
Do we want a high or low gap strain to allow the tissue to heal?
Low
73
What 2 situation can we set up for a low strain and enable tissue to heal?
* FRACTURE reduced & compressed
* COMMINUTED FRACTURE
74
What is primary healing?
Bone apposition & reduction = stability (ideally compression)
75
What is involved in secondary healing?
Bone not apposed reconstructed
Relative movement instability
Callus formation
Small amount of movement
76
Define reconstruction in relation to fracture repair
All pieces can be put back together
77
What type of fracture can be reconstructed?
Simple fracture:
* Transverse
* Oblique
* Spiral
78
Which type of fracture can be reconstructed, but only a maybe?
Segmental fracture
79
Which type of fracture cannot be reconstructed?
Communuted
80
What type of healing do you get if a bone is reconstructed and a compression plate,lag screw and positional screw was used?
Primary
81
What type of healing do you have if a bone is not reconstructed, using an ESF and bridging plate?
Secondary
82
What is involved in an Open Reduction Internal Fixation (ORIF)?
Precise anatomical reduction of bone fragments
* Bone takes some load = decreasing the stress on the implants
* Rigid fixation creates stability at fracture site
* Better load sharing bone / implant
* Less chance of implant failure
* Primary bone healing more likely
83
Name 2 issues with Open Reduction Internal Fixation as it requires more extensive surgical approach (3)
- Greater soft tissue disruption
- Compromises bone blood supply
- Bone needs blood supply to heal
84
Name the 3 issues of having small gaps between fracture ends results in
High STRAIN
Plate BENDING
Implant FAILURE
85
Name 2 problems if an implant is too stiff (3)
* Implants take too much load
* Reduced load to bone
* Wolff’s Law - bone constantly remodels to be of a strength required to manage the load placed upon it
86
What are the 4 surgical approaches to fixing a fracture?
1. Open approach
2. Open look-but-do-not-touch
3. Minimally invasive - MIPO
4. Closed approach
87
What two things do we use for non reconstructable fractures?
* Bridging Plates
* External Skeletal Fixators
88
What three things do you use for reconstructable frcactures?
* Dynamic Compression Plates
* Lag / Positional screws & Neutralisation plates
* K-wires (physeal fractures)
89
Name 4 benefits of closed redcution (5)
* Most biologic
* No surgical incision
* No surgical dissection
* No bone devascularisation
* Fracture haematoma & growth factors undisturbed
90
What is involved with MIPO Minimally Invasive Plate Osteosynthesis?
* Limited surgical incisions for implant placement only
* A bit more dissection than closed but not much
* Fluorosocpy / intra-operative X-ray guidance
* Small incision dorsally to place the screws and this preserves he biology of the bone much better!
91
What are the positives of using a "look but do not touch" approach?
* But minimise dissection to that required place implants (bridging)
* Leave fracture haematoma alone
* Allows for lag screws / compression plate i.e. reconstruction
* Leave the fragments
92
What is the problem of the " look but do not touch" approach?
Big incisions, more dissection and trauma
93
What are the benefits of using the reconstruction method?
* Minimise dissection to that required place implants
* If possible, leave fracture haematoma alone
* Allows for lag screws / compression plate i.e. reconstruction
94
Name 4 fracture factors with how likely a fracture is to heal (6)
–Open or closed
–Site, single or multiple, simple or comminuted
–Quality of bone
–Joint involvement
–Associated soft tissue damage
–Reconstructable and able to load-share?
95
Name 3 patient factors asscoiated with how likely a fracture is to heal (5)
* Is there associated (non-orthopaedic) trauma ?
* Age
* Bodyweight
* Activity levels
* Concurrent disease.
96
Name 6 factors which will give a fracture healing score of 10 (7)
* Young
* No disease/good health
* Cancellous bone
* Low veolcity injury
* Simple transverse/oblique fracture
* Single limb injury
* Closed surgical approach
97
What implant does this show?
Intra-medullary pins (IM pins)
98
Here is a table, I could not make it into a flashcard. But do enjoy xo
R u enjoying?
99
Name 4 indiciations or IM pins (6)
* Non-reconstructed comminuted fractures
* IM pin addition augments fixation strength
* COMBINE with ESF (external skeletal fixator) or bridging plate
* For intra-operative fracture alignment
–Then ESF or plate application
–Restores fracture length & stabilizes bones
•Long oblique fracture e.g. cat femur
–Combine wide IM pin with multiple cerclage
–BUT CARE as cerclage wires easily loosen & lose stability
–RARELY best choice as more stable methods available
100
Define normograde IM pin placement
From end of bone towards the fracture – generally the best way but more difficult to achieve. Harder to do and get in the right place.
101
Define retograde IM pins
From from fracture towards the bone ends – easier but can enter joints, e.g. stifle with tibial fracture or damage nerves (sciatic). No control where it exits, can exit into meniscus. Easier but harder to control exit.
102
Where can you not use IM pins?
Radius
103
Name the 4 places we can use IM pins
- Humerus
- Femur
- Tibia
- Ulna
104
Can an IM pin resist compression?
No
105
Which two fracture types will a pin not prevent compression?
Oblique or comminuted
106
What does compression lead to with a transverse fracture?
Stable
107
What does compression cause with an oblique/spiral fracture?
Shear
108
What are IM pins strong against?
Bending as positioned in the 'neutral' axis
109
What can IM pins not resist?
Rotation
110
What are the 3 things wire can be used as?
* Cerclage wire
* Tension band
* Hemicerclage wire / other
111
Define cerclage wire
Orthopaedic wire used as a loop around bone
112
What does this show?
Cerclage
113
What does this show?
Hemi-cerclage
114
What is Newton's 2nd law?
To every action there is an equal and opposite reaction
For each force there is an equal and opposite force
115
What are the principles of tension band wire?
* The wire resists major forces so must be thick
* Pins maintain alignment and prevent shear
* Cortex that forms the bending point must be intact
* Most effective when animal is weight-bearing (dynamic)
116
Name 3 common problems of cerclage wire? (4)
* Placed inappropriately
* Require more dissection to place
* Loosen quickly and easily
* Once loose, wobble and cause injury to bone & vessels that prevents / retards healing
117
Name 7 of the main principles of using cerclage wire? (9)
* Cerclage wires encircle the bone and the two ends are twisted to tighten and reconstruct the column of bone
* Important to twist wires around each other
* Reconstructable fracture
* Oblique / spiral fractures only
* Bone must have even shape, not narrowing
* Length of fracture line must be at least 2 x bone diameter
* Minimum 2 cerclage wires
* Wires placed 1cm apart
* Wires placed at least 5 mm from fracture end
118
What do you do with the ends of the cerclage twist wires?
* Must always pull (exert tension) as you twist so that ends twist around each other evenly
* Either cut ends short (1.5 twists), or leave longer (3-4 twists) and bend end over
119
When is most of the tension of cerclage twist wires lost?
When ends are bent
120
How many twists must you leave in cerclage wire?
At least 3-4
121
With a cerclage wire singleloop, what 2 things do you need?
* Single eyed cerclage wire
* Single wire tightener
122
What are the 2 advantages of using cerclage wire as a single loop?
More robust & neater
Easier to place well
123
What 2 things do we need to place a double loop cerclage wire?
* Normal orthopaedic wire
* Double wire tightener
124
Cerclage wire - double loop:
A) What is an advantage?
B) What is the disadvantage?
A) Robust
B) Difficult to place
125
Cerlcage wire twist:
A) Name the advantage
B) Name 2 disadvantages (4)
A) Cheapest & “simplest”
B) Weakest, most likely to fail
Need to “pull” and twist” to get even twist - each wire round the other
Leave at least 3-4 twists.
Bending over loses tension in the know
