Frakturer Flashcards
Athletic animals such as greyhounds are prone to a certain type of fracture, and fractures of 3 sites.
stress fractures
and fractures of accessory carpal, radial carpal and central tarsal bone.
After a traumatic fracture thoracic radiographs should be taken to check for the
following (listed in order of likelihood) 4 st
pulmonary contusions,
• pneumothorax
• fractured ribs
• other thoracic problems (such as ruptured diaphragm).
Which supportive dressings whilst awaiting surgery or transporting;
A: BELOW ELBOW AND STIFLE –
B; ABOVE ELBOW AND STIFLE –
A : Support with Robert
Jones or modified Robert Jones with splint
B : A Spica splint is
sometimes applied or more commonly strict cage rest is
acceptable
Primary bone healing is usually possible only with internal fixation techniques
due to the requirement for absolute rigidity with less than how much strain?
2% strain
Early treatment during the ‘golden period of __ hours where if contamination is minimal then the fracture may be treated as a closed fracture.
of 4-6 hours’
Incomplete fractures (3)
▪ Greenstick fractures may be stable and should heal
providing disruptive forces are neutralised.
▪ Fissure fractures can open if inappropriate fixation
methods are used potentially making a fracture more
complicated.
▪ Depression fractures usually occur in the skull and are the
result of multiple fissures with anatomical displacement of a
section of flat bone in the direction of the force. Further
displacement into the cavity must be resisted but
anatomical reconstruction is not always necessary unless
the displacement is resulting in a problem due to pressure
on the underlying structures.
Fracture Classification (11 st)
¤Causal factors
¤Open/closed
¤Incomplete/complete
¤Simple/ comminuted/ segmental
¤Displacement (the distal fragment)
¤Location- Metaphyseal / Diaphyseal ( Proximal, Mid, Distal) / Articular / Condylar/ Physeal (Salter Harris) – Growth disturbances are common
¤Fracture morphology- Simple/Wedge/Complex
¤Orientation of fracture line- Transverse/ Oblique/ Spiral/ Incomplete (greenstick in young animal – periosteum often intact)
¤Forces acting on the fracture / displacement - Avulsion, Impaction, Compression, Overriding
¤Stable/unstable
¤Age of fracture
Forces acting on bone:
Compression, bending, torsion, shear and
tension
Describe forces acting on the fracture / displacement when and where does following accur: o Avulsion : o Impaction o Compression o Overriding
Forces acting on the fracture / displacement
o Avulsion – fractures affect a fragment of bone at the site of
insertion of a muscle tendon or ligament
o Impaction occurs when a bony fragment (generally cortical) is
forced or impacted into cancellous bone – typically occurs at the
end of long bone
o Compression – occurs when cancellous bone collapses and
compresses upon itself – usually vertebral body.
o Overriding – describe direction the most distal fragment has
displaced e.g. proximal, cranial and medial
Time frame when treating fractures:
Open fractures and fractures of the skull or spine:
o Articular fractures and dislocations :
o Long bone fractures ;
Open fractures and fractures of the skull or spine require the most
urgent treatment
o Articular fractures and dislocations should be dealt with within 24 to
48 hours
o Long bone fractures should be treated within 5-7 days
Aims for spatial realignment (2)
maintenance of bone length and less than 5° of angular or rotational
malalignment.
Special considerations regarding type and quality of bone involved-
¤ In young animals
¤ osteopenic bone
¤ underlying bone disease such as nutritional secondary hyperparathyroidism
Type and quality of bone involved
In young animals the bone is relatively soft and screws will easily strip their
threads, similarly in osteopenic bone screw holding is poor. If there is underlying
bone disease such as nutritional secondary hyperparathyroidism then fractures
may be best treated conservatively.
Casts and splints- what kind of fractures/ patients is suitable?
▪ Must be possible to immobilise the joint proximal and distal
to the fracture
▪ Reserved for transverse or very short oblique fractures
▪ At least 50% of the fracture should be in contact following
reduction
▪ Casts have greater success in young patients
o Fractures in the lower limb
o Simple fractures with some intrinsic stability
▪ Transverse or interdigitating fractures
▪ Fractures of the radius (or tibia) where the ulna (or fibula)
are intact
▪ On two orthogonal radiographs there should be at least
50% of the fracture ends in contact
o Fractures in animals with good healing potential ensuring rapid
bone union & thus avoiding overlong immobilisation (immature
animals). For example an ideal patient for cast stabilisation would
be a 5 month puppy with a simple interdigitating fracture of the
tibia with an intact fibula.
o Resist temptation – often not cheaper ESPECIALLY IF THINGS
GO WRONG
Cerklage size in:
Cats and Small Dogs
Medium dogs
Large Dogs
Cats and Small Dogs: 22 Gauge (0.8mm) Medium dogs 20 Gauge (1mm) Large Dogs(>20kg) 18 Gauge (1.2mm)
Size; Steinmann pins / K wires
Steinmann pins (1.5mm to 6.5mm) and K wires (0.9mm to 1.5mm)
Pin size measured from Xrays:
Cats special consideration:
Mid-shaft fractures :% of medullary canal
Combine an IM pin with a plate: % of medullary canal
Pin size selection should be based on radiographs
o Pin diameter is influenced by the shape of the bone. Cats have
straight bones which allow potentially larger pins. This can be a
disadvantage as too large of pin can result in interference with
medullary blood supply and so delay the union.
o For mid-shaft fractures aims for a 60-70% fill of the medullary
cavity at its narrowest point. Always start with a smaller pin as you
can increase the size of the pin.
o If you start with a large pin and need to put a smaller one the entry
hole will be too large which will reduce the stability of the pin and
repair.
o IM pin with a plate : size of the pin is reduced to fill approximately 30% of the canal width.
Normograde/ Retrograde pinning preferred for femur and why?
Normograde preferred for femur
▪ Pin placement more precise and less manipulation of the
fracture
▪ Insert from trochanteric fossa
▪ Reduced risk of sciatic nerve injury
▪ May be difficult to identify the correct entry point into the
bone
o Retrograde simpler but places pin in a more caudomedial position
▪ Increased risk of sciatic nerve injury
▪ Extending and adducting coxofemoral joint helps avoid
sciatic nerve
Cross pinning which type of fractures suitable?
Stability is increased with this method by: (3)
Cross pinning
Simple Salter Harris or metaphyseal fractures can often be repaired with a
cross pin technique starting from the sides of the joint.
Stability is increased with this method by:
• Ensuring the pins do not cross at the level of the fracture
• The pins gaining purchase by penetrating the trans cortex
• If the pins do not penetrate the opposite cortex ‘dynamic stability’ can be
gained by bouncing the pin off the opposite cortex before continuing up
the medullary canal. This is known as rush pinning although there is no
evidence to recommend the use of this technique.
A: screw placement; - Countersinking should be performed when:
B: This procedure is not performed in:
A: the screw head is to contact cortical bone directly (rather than via a bone plate)
B: metaphyseal and epiphyseal bone, because the cortex is too thin in these
regions. In such cases a flat washer can be used as an alternative, to allow
a better distribution of loads, especially if the screw is placed in soft bone
(e.g. skeletally immature animals).
Screw size: holes made within the bone will not significantly
affect its mechanical properties providing that the hole diameter does not exceed
?? % the diameter of the bone.
20
Plate placement, tension side: Femur Tibia Humerus Radius
Femur lateral
Tibia medial/cranial
Humerus lateral/cranial
Radius medial/craniomediL
ESF pin size- %of bone diameter
max 30%
ESF Use full pins (and hence Type II frames) for what kind of fractures?
comminuted fractures (when load sharing will not be possible).
ESF: For proximal limb fractures, use :
tied-in intramedullary pin because it is
not possible to apply a bilateral fixator here
