SA Fractures 2

Question 1

Types of implants.

Answer 1

Pins.
Orthopaedic wire.
Screws.
Bone plates.
External skeletal fixators.
*Can use either in isolation or combination for fracture stabilisation.

Question 2

Bone pins.

Answer 2

Stainless steel and sharp tipped.
AKA - Kirschner wires / K wire / A wires / Steinmann pins.
Low carbon - less likely to rust.
Uses:
- intramedullary.
- transosseous.
- pin and TBW (tension band wire).

Question 3

Complications of intramedullary pinning.

Answer 3

Fractures rarely suitable for IM pinning in isolation.
Better in combination with something else.
Instability can cause loosening of the pin.
IM pin not good at resisting rotation.

Question 4

Interlocking nail.

Answer 4

Stainless steel and used as IM pin.
Locked in place using screws.
Prevents rotation and axial collapse.

Question 5

Pin and tension band wire.

Answer 5

1 or 2 K wire / pins - through fragment into bone.
Ortho wire in a figure of 8:
- through hole in bone.
- and around pins.
Uses:
- avulsion fractures.

Question 6

Orthopaedic wire.

Answer 6

Malleable stainless steel wire.
Uses:
- wire placed to.
– completely encircle bone (cerclage).
…or…
– partially encircle bone (hemi-cerclage).
- tension band wire (TBW).

Question 7

Bone screws.

Answer 7

Stainless steel e.g. cortical, cancellous, locking, self-tapping or non self tapping.
Uses:
- with a plate or interlocking nail.
- in isolation for fractures of cancellous bone.
- never use in isolation for diaphyseal fractures (slower healing and greater forces through bone).
- compress fragments together in lag fashion to enable rapid primary (direct) bone healing without callus.
Named according to size (mm).

Question 8

Bone plates.

Answer 8

Restore bone structure to restore WB function and enable healing.
Compresses fractures - transverse.
Neutralisation - takes force off the bone - comminuted/long oblique fractures.
Buttress plate - plate takes all load
– for v comminuted fractures with larger gaps.
Elastic osteosynthesis - minimal screws – where fractures are likely to heal quickly.

Question 9

External Skeletal Fixation (ESF).

Answer 9

Versatile fixation system.
Main uses:
- comminuted fractures.
- open fracture.
- across joints.
Some complications.
Threaded transosseous pins.
Clamps.
Bars.
Acrylic - light weight.

Question 10

Diaphyseal fracture repair choices.

Answer 10

Spiral / oblique:
- pin and cerclage wire in young animals.
- plate and screws – ?interlocking nail, ESF (and pin).
Transverse:
- cast.
- plate and screws – ?interlocking nail, ESF (and pin).
Comminuted:
- plate and screws – ?interlocking nail, ESF (and pin).
- plate, screws and IM pin.
Classify the fracture, consider mechanical, biological and client factors, consider all options, rule out options, compare and contrast options, decide on best.

Question 11

Principles of articular fracture repair.

Answer 11

Perfect reduction.
Rigid internal fixation.
Compression of gap (lag screw or bone reduction forceps).
- for direct bone healing.
Early mobilisation.

Question 12

Avulsion fractures.

Answer 12

Injury to the bone in a location where a tendon or ligament attaches to the bone. When an avulsion fracture occurs, the tendon or ligament pulls off a piece of bone.
Common locations:
- olecranon.
- greater trochanter.
- medial malleolus.
- aromium of scapula.
- os calcaneus.
- tibial tuberosity.
Repair with tension band wire.
- active distracting forces are counteracted and converted into compressive forces.
Can also repair with a tension band plate.

Question 13

Physeal (growth plate) fractures.

Answer 13

Physis 3-5 times weaker than ligament attachment to bone.
Type of growth plates.
- pressure (long bone).
- traction (e.g. tibial tuberosity).
Salter and Harris classification of physeal fractures:
- I = across physis.
- II = across physis and a bit of metaphysis.
- III = articular
- IV = articular with some metaphysis included.
- V = compression of physis.
- VI = compression of physis

Question 14

Physeal fracture surgical principles.

Answer 14

Early surgery - bone cancellous and remodels rapidly.
Articular fracture - priority over physeal aspect.
Careful surgical technique - soft bone crushable.
Consider external coaptation if minimal displacement and non-articular.
Small smooth implants.
Perpendicular to growth plate.
Implants should damage <10% SA of physis.
Avoid compressing physis.
Consider implant removal.