Appendicular fracture repair Flashcards
Approach to fracture management
Establish the location and the nature of the fracture
Fracture assessment
List all possible methods of fracture repair
Weigh up advantages and disadvantages of each method
Establish best options
Fracture classification parameters
- Cause of fracture
- Communication with external environment
- Extent of bony damage
- Number and position of fragments
- Direction of fracture lines
- Location
- Forces acting on the fracture/displacement
- Stability
- Degree of complexity and involvement of other tissues
- Age
Forces acting on transverse fractures
Shear +
Compression +++
Forces acting on oblique/spiral fractures
Bending +
Torsion +
High risk fractures based on biologic fracture assessment
Old patient
Poor health
Poor soft tissue envelope
Cortical bone
High velocity injury
Extensive approach
Mechanical fracture assessment
Caution:
- comminuted fracture
- multiple limb injury
- giant breed
In the middle:
- segmented fracture
- pre-existing clinical disease
- large dog
Little risk:
- transverse fracture
- single limb
- toy dog
High risk fractures according to clinical fracture assessment
Poor client compliance
Poor patient compliance
Wimp
High comfort level required
Methods for primary fixation
External coaptation (cast or splint)
Intramedullary pin and/or K-wires
External skeletal fixator
Interlocking nail
Bone and plate screws
Methods of ancillary internal fixation
Intramedullary pin and/or k-wires
Lag screws
Cerclage wire
Aim of diaphyseal fracture repair
To repair it with as simple and as reliable a method as possible.
Articular fractures
Disruption of the articular surface will inevitably lead to some degree of degenerative change
Goal of surgery is to slow the onset/progression of arthritis, and reduce the impact on quality of life
Principles of articular fracture repair
Perfect reduction of the articular surface
Use rigid internal fixation
And interfragmentary compression of the fracture gap - using lag screws (+/- plates)
Early mobilisation and use of the joint is important to minimise stiffness.
Avulsion fractures
An avulsion fracture is where a fragment of bone is pulled away at the ligamentous or tendinous attachment.
Accurate anatomical reduction of the fracture needed
Rigid internal fixation (beware can be tiny fragments)
Implants must resist the tensile forces that caused the fracture in the first place
Principles of avulsion fracture repair
Counteract active distracting forces and convert them into compressive forces using the tension band principle.
Humeral diaphyseal fractures
Frequently distal half to third
Cast fixation not appropriate (upper limb)
IM pin fixation can be used but the bone narrows significantly distally restricting the size of pin that can be used.
Plate fixation is often an appropriate choice but both the surgical approach and the shape of the bone do not make this an easy option. Tension side of the humerus is the cranial or lateral. However applying a plate on the medial surface is acceptable practice.
ESF fixation should be avoided in the upper limb if a simpler option is appropriate
What are the tension sides of the humerus?
Tension side of the humerus is the cranial or lateral.
Radial diaphyseal fractures
Distal diaphyseal fractures are most common.
Surgical approaches – medial or lateral.
External coaptation is suitable for simple fractures with stability and good apposition of fracture ends.
IM pins and interlocking nails are NOT suitable as there is no safe area for placement of these implants that will not cause damage to the articular surfaces.
Plate and screw repair on the cranial or medial aspect is best for simple fractures.
In large dogs it may be necessary or preferable to plate both the radius and ulna.
If fracture is comminuted then ESF should be considered, although placement of pins in the radius, which is quite a narrow bone, can be a frustrating job.
Distal Radial and Ulna Fractures – metaphyseal or epiphyseal
Fractures proximal to the growth plate are common especially in small or toy breeds of dog.
These fractures are prone to non-union, most commonly atrophic, if treated sub-optimally.
External coaptation is not advised.
Rigid stabilisation with ORIF using a bone plate and screws is recommended or use of external skeletal fixation may also be suitable.
Short plates risk implant related fracture due to ‘stress-riser’ effect.
Risk of osteopenia of the bone underneath plate, leading to secondary fractures.
Ulna diaphyseal fractures
Isolated ulna fractures uncommon
Usually don’t need repair
If in combination with radial fracture often doesn’t need fixation but can help stabilise
Can IM pin or plate fixation (caudal or lateral aspect)
Femoral diaphyseal fractures
One of the most commonly fractured bones.
Surgical access will be from lateral
Repair options include:
○ External coaptation / cast – NOT appropriate for upper limb bone
○ IM pins – usually combined with cerclage wires for a long oblique fracture or an ESF (cats). The IM pin should be inserted in a normograde manner to avoid any damage to the sciatic nerve if it loosens and migrates.
○ Interlocking nail – for mid diaphyseal fractures
○ Plate and screws – place on lateral aspect of the bone
○ ESF – to be avoided if possible as large muscle mass for pins to go through which will cause patient some morbidity – especially in dogs. With severely comminuted unreconstructable fractures may be most appropriate option.
Tibial diaphyseal fractures
Surgical Approach – medial (easy approach). Medial side is tension side of bone and gives best surgical access for plate fixation.
Remember to assess whether fibula is intact when assessing fracture.
Repair methods –
○ External coaptation,
○ IM pinning. Pin size dictated by distal tibia (narrow). Pin placed in a normo-grade fashion from starting on the craniomedial aspect of the tibia.
○ Interlocking nails can also be used – narrow size of tibia may restrict use.
○ ORIF with plates and screws
○ Closed reduction and application of an ESF -unilateral or bilateral or bilateral biplanar all possible
Scapular neck fractures
Treated with ORIF
Can be difficult to expose and fragments often small and difficult to adequately stabilise
Fracture of the humeral condyle
Common fracture
Surgical repair essential
Three types:
* fracture of the lateral aspect of the condyle (70%)
* fracture of both the lateral and medial aspects of the condyle - Y or T fracture (25%)
* fracture of the medial aspect of the condyle (7%)
Signalment for fracture of lateral aspect of humeral condyle
Breeds - usually toy breeds (Min Poodle, Yorkie) or Labradors and Spaniels
Age - often young - 3 mths
Cause - the fracture often occurs after minimal trauma - eg jumping from a chair or being dropped.
Pathogenesis of a fracture of lateral aspect of humeral condyle
the fracture is a shear injury as the radius articulates with the lateral aspect of the humeral condyle and force is transferred through the radius to the humerus on landing.
Clinical signs of a fracture of lateral aspect of humeral condyle
sudden onset forelimb lameness after minimal trauma. Elbow pain and crepitus on manipulation. Careful palpation may reveal asymmetry of the two epicondyles with the medial epicondyle displaced distally.
Diagnosis of a fracture of lateral aspect of humeral condyle
radiography is essential if this problem is suspected. Mediolateral and craniocaudal views should be taken. It may be useful to radiograph the contralateral elbow as the fragment may be minimally displaced and the multiple open growth plates can make interpretation difficult. The fracture is a Salter Harris Type IV fracture
Treatment of a fracture of lateral aspect of humeral condyle
ORIF is essential.
Principles of fracture fixation of an articular surface should be followed
Implants - a lag screw, washer and anti-rotational K wire are usually sufficient.
If adequate facilities for surgery are not available at your practice then the dog should be referred.
Surgery should be performed as soon as possible - preferably within 24-48 hours.
Prognosis of a fracture of lateral aspect of humeral condyle
With early surgery, accurate reduction and compression of the fragment the prognosis is fairly good (good to excellent in 90 percent of cases).
A malunion or delay in surgery may result in an adverse outcome - in some cases amputation is eventually required.
Y fracture
fracture of both the lateral and medial aspect of the humeral condyle (also called T or bicondylar fracture)
Signalment of a y fracture
Breeds - any, Labrador and Spaniels may be overrepresented.
Age - animals often mature
Cause - the trauma is often severe eg RTA. Occasionally in predisposed breeds trauma may be more minor e.g. - catch foot in rabbit hole, jump off truck
OR uderlying HIF
HIF
Humeral inrtacondylar fissure
Signalment of HIF (humeral intracondylar fissure)
Seen most commonly in Spaniels (Springer Spaniels in the UK), but other breeds can be affected as well.
Clinical presentation of a Y fracture
Sudden onset non-weight bearing lameness.
Marked crepitus, instability, swelling and pain will be present.
Concurrent injuries should be checked for after severe trauma.
Surgery for Y fracture
Referral highly recommended
ORIF essential
Early surgery recommended (24-48hrs)
Medial bone plate and screws.
Prognosis of Y fracture
The prognosis is guarded for a full return to function.
However with adequate early stabilisation and uncomplicated fracture healing a good result can be obtained.
Good to excellent outcome in around 40% of cases, over half of the affected dogs remain lame.
Fracture of the medial aspect of the humeral condyle
The least common type of humeral condylar fracture. Management similar to that of fractures of the lateral aspect of the condyle.
Acetabular fractures
should be managed with ORIF.
Severely comminuted fractures may be managed without surgery but a femoral head and neck excision (or a total hip replacement) may become necessary
Implants used in repair of an acetabular fracture
acetabular plates and screws, reconstruction plates and screws or screws, wire and polymethylmethacrylate (bone cement).
Prognosis of acetabular fractures
influenced by the degree of comminution & articular damage – arthritis is likely to result as the fracture is articular and owners should be pre-warned of the possibility of lameness.
Avulsion of the supraglenoid tuberosity
Can occur in active, young large breed dogs.
This fracture occurs through a growth plate.
The fragment is distracted by the pull of the biceps brachii tendon.
Repair using K wires and a TBW or a lag screw is recommended in acute cases.
Chronic cases may be seen - if the fragment is irreducible then it can be excised and the biceps tendon tenodesed to the proximal humerus using a screw and spiked washer.
Acromion fractures
These are very rare.
They are also avulsion fractures (distracted by the deltoid muscle) and need repair with a wire mattress suture - the anatomy of the bone does not lend itself to pins & a TBW.
Olecranon fractures
These usually occur secondary to trauma or a fall.
Check for concurrent injuries.
They are avulsion fractures due to the pull of the triceps muscle.
Presenting signs of olecranon fractures
inability to support weight or keep elbow extended
Treatment of olecranon fractures
the tension band principle should be applied, using either k wires and a TBW or a plate on the caudal or lateral aspect of the ulna.
A bone plate and screws may be preferable if the fracture is articular.
Prognosis of an olecranon fracture
good if the fracture is not articular and adequate stabilisation is achieved.
For an articular fracture the prognosis is guarded as arthritis is likely to develop and result in intermittent or permanent lameness.
Calcaneal fracture clinical signs
Animal will be unable to keep hock extended - animal will be non-weightbearing or walk with hyperflexed hock and plantigrade stance.
The toes will still be be in a hyperflexed position giving the animal a claw foot appearance.
Where do the extensor muscles of the hock insert?
The tuber calcanei.
What type of fractures are calcaneal fractures?
Avulsion fractures due to attachment of calcaneal tendon
How should you fix a calcaneal fracture?
Reduced and stabilised with a pin and a tension band wire, a lag screw, or a bone plate and screws (applied to the caudal or caudolateral surface of the bone.
Greater trochanter fractures
Can be seen in isolation or in combination with femoral head fractures and should be repaired with K-wires and a tension band wire.
Premature closure may result in coxa valga.
Patella rfactures
Uncommon avulsion fractures
Animal will be unable to extend the stifle during weight bearing
Signalment of patella fractures
Any age, breed or sex affected. Athletic (greyhounds) or lively dogs may be pre disposed.
How may a patella fracture occur?
Fractures may occur after excessive contraction of the quadriceps with a flexed stifle and fixed foot, or from a direct blow or fall on the patella.
Physical exam of patella fractures
there will be palpable swelling over the cranial aspect of the stifle and often a severe lameness characterised by hyperflexion of the leg when attempts are made to weight bear.
Diagnosis of patella fractures
radiography is most helpful. Stressed views with the limb in extension and flexion and comparison with the opposite limb can be useful in accentuating the displacement. Bipartite patellas can occasionally be seen in cats as an incidental finding.
Types of patella fractures
- Transverse fractures through the central aspect
- Small ‘chip’ fractures at the distal (more commonly) or proximal pole
- Comminuted fractures
- Rarely longitudinal fractures
Management of patella fractures
Transverse fractures are repaired using a pin and tension band wire.
Small chip fractures are treated as quadriceps tendon ruptures - by excision of the bone fragment and reattachment of the patella tendon to the bone by use of a Bunnell suture secured to the patella through a bone tunnel.
Comminuted fractures can be treated by excision of the fragments and repair of the soft tissues, or by a patella graft (Ref: Vaughan ). To take some of the tension off the repair it is useful to place an encircling wire suture through a tunnel in the tibial tuberosity and proximal to, or through a bone tunnel, in the patella, or by placement of a TESF.
Longitudinal fractures are repaired with a lag screw
Patella fractures in cats
may not be purely traumatic, but stress fractures - treatment with encircling wire plus patella-tibial suture – no bony healing to be expected, but will lead to stable fibrosis – affected cats may develop bilateral patella fractures and other spontaneous fractures later in life.
Tibial tuberosity avulsion fracture
Usually seen in 3-5mths terriers or sight hounds.
Dogs present with swelling in the region and lameness with an inability or reluctance to weight bear with an extended stifle.
Repair with figure of 8 TBW and 2 K wires. Wire and pins should be removed in immature animal to prevent premature closure of tibial tuberosity growth plate and ‘drift’ of tuberosity distally.
Tibial tuberosity avulsion combined with tibial plateau fracture
The tibial tuberosity fuses with the tibial plateau at about 5 months so trauma in a dog of this age may cause the two pieces of bone to displace together.
The tibial plateau tends to tilt caudally.
Repair of the tuberosity alone is often sufficient (8 TBW & 2 K wires).
Malleolar fractures
Avulsion fractures as the collateral ligaments originate from the malleoli.
Repair of reasonable sized fragments should be attempted with K-wires and a tension band wire or a lag screw.
If the bone fragment is very small or comminuted then the collateral ligament may need to be reattached using a locking loop suture and a screw and washer as an anchor point.
Carpal fractures
Fractures of isolated carpal bones are rare in dogs other than Greyhounds, however they do occur and to ensure accurate diagnosis high quality radiographs of the carpus taken from multiple angles should be obtained and the contra-lateral limb radiographed for comparison.
In general treatment of choice for theses injuries is anatomic reduction and internal fixation although small chip fractures may be treated with fragment excision.
Radiocarpal bone fractures
These are occasionally seen in energetic medium sized breeds. Boxers, Labradors and Springer Spaniels seem to be over represented.
An oblique fracture line is seen running in a proximolateral to distomedial direction.
The fracture may be subtle initially with minimal displacement and in early cases the condition may be missed.
The fracture may be seen bilaterally. It is useful to compare the contralateral carpus.
Treatment – conservative if minimal signs, lag screw fixation in early cases or carpal arthrodesis.
Accessory carpal bone fractures
These are the most common carpal fractures seen in Greyhounds. Mostly they are classified in V types. Type I is the commonest fracture seen in greyhounds. Fracture fragments are generally small. Early repair with lag screw fixation can result in 70% of dogs returning to racing.
Fractures of the metacarpals
Metacarpal (MC) bone fractures occur not uncommonly in cats and dogs.
If only 1 or 2 bones are fractured then these will be splinted by the intact MC bones, and external coaptation may provide enough support during healing.
However the 3rd & 4th digits are the main weight bearers and fractures affecting the 3rd & 4th MC/MT bones are more likely to need repair.
If 2 or more bones are fractured then ORIF may be indicated.
If the bones are large enough then repair with plates and bone screws is optimal.
In smaller bones IM pinning using Kirschner wires is the best option combined with external coaptation.
Fractures of the phalanges
can usually be treated with external coaptation. In large dogs with simple oblique fractures or in greyhounds then ORIF using lag screws or plates and bone screws may be useful.
Fabellae fractures
Very rare. Lameness associated with pain over the affected area of the gastrocnemius muscle is seen. Radiographs show mild displacement of fracture fragments. Management – conservative or surgical repair. Prognosis good
Talar fractures
Fractures of this bone are rare. Fractures can be classified as articular or non-articular.
Articular – osteochondral fragments of the trochlear ridges may be associated with avulsion of the insertion of the collateral ligaments. Small fragments are removed, larger ones are repaired with ORIF. Prognosis is variable dependant on the degree of articular surface affected and the resultant joint congruity. In severe fractures arthrodesis may be indicated
Non articular – Talar neck fractures are seen in cats often associated with luxation of the base of the bone. ORIF is recommended followed by external coaptation. Prognosis is reasonable
Central tarsal bone fractures
These occur most often in racing greyhounds & coursing breeds. The right CTB is commonly fractured in greyhounds because they race in an anticlockwise direction. The CTB is important for load transmission and once it is fractured the medial buttress is lost and other bones may subsequently or concurrently fracture, although often to a lesser degree. Fractures of the CTB are classified from Type I-V with type IV being the commonest. ORIF is indicated if the dog is to have a chance to return to athletic performance.
