Appendicular fracture repair

Question 1

Approach to fracture management

Answer 1

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

Question 2

Fracture classification parameters

Answer 2

1. Cause of fracture
2. Communication with external environment
3. Extent of bony damage
4. Number and position of fragments
5. Direction of fracture lines
6. Location
7. Forces acting on the fracture/displacement
8. Stability
9. Degree of complexity and involvement of other tissues
10. Age

Question 3

Forces acting on transverse fractures

Answer 3

Shear +
Compression +++

Question 4

Forces acting on oblique/spiral fractures

Answer 4

Bending +
Torsion +

Question 5

High risk fractures based on biologic fracture assessment

Answer 5

Old patient

Poor health

Poor soft tissue envelope

Cortical bone

High velocity injury

Extensive approach

Question 6

Mechanical fracture assessment

Answer 6

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

Question 7

High risk fractures according to clinical fracture assessment

Answer 7

Poor client compliance

Poor patient compliance

Wimp

High comfort level required

Question 8

Methods for primary fixation

Answer 8

External coaptation (cast or splint)

Intramedullary pin and/or K-wires

External skeletal fixator

Interlocking nail

Bone and plate screws

Question 9

Methods of ancillary internal fixation

Answer 9

Intramedullary pin and/or k-wires

Lag screws

Cerclage wire

Question 10

Aim of diaphyseal fracture repair

Answer 10

To repair it with as simple and as reliable a method as possible.

Question 11

Articular fractures

Answer 11

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

Question 12

Principles of articular fracture repair

Answer 12

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.

Question 13

Avulsion fractures

Answer 13

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

Question 14

Principles of avulsion fracture repair

Answer 14

Counteract active distracting forces and convert them into compressive forces using the tension band principle.

Question 15

Humeral diaphyseal fractures

Answer 15

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

Question 16

What are the tension sides of the humerus?

Answer 16

Tension side of the humerus is the cranial or lateral.

Question 17

Radial diaphyseal fractures

Answer 17

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.

Question 18

Distal Radial and Ulna Fractures – metaphyseal or epiphyseal

Answer 18

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.

Question 19

Ulna diaphyseal fractures

Answer 19

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)

Question 20

Femoral diaphyseal fractures

Answer 20

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.

Question 21

Tibial diaphyseal fractures

Answer 21

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

Question 22

Scapular neck fractures

Answer 22

Treated with ORIF

Can be difficult to expose and fragments often small and difficult to adequately stabilise

Question 23

Fracture of the humeral condyle

Answer 23

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%)

Question 24

Signalment for fracture of lateral aspect of humeral condyle

Answer 24

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.

Question 25

Pathogenesis of a fracture of lateral aspect of humeral condyle

Answer 25

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.

Question 26

Clinical signs of a fracture of lateral aspect of humeral condyle

Answer 26

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.

Question 27

Diagnosis of a fracture of lateral aspect of humeral condyle

Answer 27

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

Question 28

Treatment of a fracture of lateral aspect of humeral condyle

Answer 28

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.

Question 29

Prognosis of a fracture of lateral aspect of humeral condyle

Answer 29

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.

Question 30

Y fracture

Answer 30

fracture of both the lateral and medial aspect of the humeral condyle (also called T or bicondylar fracture)

Question 31

Signalment of a y fracture

Answer 31

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

Question 32

HIF

Answer 32

Humeral inrtacondylar fissure

Question 33

Signalment of HIF (humeral intracondylar fissure)

Answer 33

Seen most commonly in Spaniels (Springer Spaniels in the UK), but other breeds can be affected as well.

Question 34

Clinical presentation of a Y fracture

Answer 34

Sudden onset non-weight bearing lameness. Marked crepitus, instability, swelling and pain will be present. Concurrent injuries should be checked for after severe trauma.

Question 35

Surgery for Y fracture

Answer 35

Referral highly recommended ORIF essential Early surgery recommended (24-48hrs) Medial bone plate and screws.

Question 36

Prognosis of Y fracture

Answer 36

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.

Question 37

Fracture of the medial aspect of the humeral condyle

Answer 37

The least common type of humeral condylar fracture. Management similar to that of fractures of the lateral aspect of the condyle.

Question 38

Acetabular fractures

Answer 38

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

Question 39

Implants used in repair of an acetabular fracture

Answer 39

acetabular plates and screws, reconstruction plates and screws or screws, wire and polymethylmethacrylate (bone cement).

Question 40

Prognosis of acetabular fractures

Answer 40

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.

Question 41

Avulsion of the supraglenoid tuberosity

Answer 41

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.

Question 42

Acromion fractures

Answer 42

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.

Question 43

Olecranon fractures

Answer 43

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.

Question 44

Presenting signs of olecranon fractures

Answer 44

inability to support weight or keep elbow extended

Question 45

Treatment of olecranon fractures

Answer 45

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.

Question 46

Prognosis of an olecranon fracture

Answer 46

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.

Question 47

Calcaneal fracture clinical signs

Answer 47

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.

Question 48

Where do the extensor muscles of the hock insert?

Answer 48

The tuber calcanei.

Question 49

What type of fractures are calcaneal fractures?

Answer 49

Avulsion fractures due to attachment of calcaneal tendon

Question 50

How should you fix a calcaneal fracture?

Answer 50

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.

Question 51

Greater trochanter fractures

Answer 51

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.

Question 52

Patella rfactures

Answer 52

Uncommon avulsion fractures Animal will be unable to extend the stifle during weight bearing

Question 53

Signalment of patella fractures

Answer 53

Any age, breed or sex affected. Athletic (greyhounds) or lively dogs may be pre disposed.

Question 54

How may a patella fracture occur?

Answer 54

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.

Question 55

Physical exam of patella fractures

Answer 55

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.

Question 56

Diagnosis of patella fractures

Answer 56

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.

Question 57

Types of patella fractures

Answer 57

* Transverse fractures through the central aspect * Small ‘chip’ fractures at the distal (more commonly) or proximal pole * Comminuted fractures * Rarely longitudinal fractures

Question 58

Management of patella fractures

Answer 58

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

Question 59

Patella fractures in cats

Answer 59

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.

Question 60

Tibial tuberosity avulsion fracture

Answer 60

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.

Question 61

Tibial tuberosity avulsion combined with tibial plateau fracture

Answer 61

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).

Question 62

Malleolar fractures

Answer 62

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.

Question 63

Carpal fractures

Answer 63

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.

Question 64

Radiocarpal bone fractures

Answer 64

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.

Question 65

Accessory carpal bone fractures

Answer 65

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.

Question 66

Fractures of the metacarpals

Answer 66

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.

Question 67

Fractures of the phalanges

Answer 67

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.

Question 68

Fabellae fractures

Answer 68

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

Question 69

Talar fractures

Answer 69

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

Question 70

Central tarsal bone fractures

Answer 70

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.