Locomotor - Non-diaphyseal Bone Fracture Healing Flashcards Preview

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Flashcards in Locomotor - Non-diaphyseal Bone Fracture Healing Deck (12)
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What are the forces that act on non-diaphyseal (epiphyseal) bone vs. diaphyseal bone that can lead to fractures?

Compression is the only force that acts on sites of fracture in non-diaphyseal. Compression comes from the impact of weight-bearing, not twising or bending as in the case of diaphyseal-bone fractures.

In diaphyseal bone, compression, shear, torsion and tension occur at the site of fracture. 


Since compression is the only force acting upon non-diaphyseal-bone fracture sites, what implications does this have for the type of fixation to use for healing?

The compression forces are typically lower on the non-diaphyseal-bone fracture sites, so the fixation methods can be "lighter".



What are all the different types of non-diaphyseal-bone fractures that occur?

(Think here especially of joints and other points where bones articulate with each other)


Intra-articular or Peri-articular

Intracapsular non-articular

Extra-capsular non-articular (aka metaphyseal)




What is avulsion and give some examples of a fracture caused by avulsion.

These are fractures of major muscular insertions close to joints due to force of muscle.


- Gluteal muscles & abductors of the hindlimb insert into the major trochanter of the femur and can pull off the trochanter.

- Triceps pull off a fragment of the olecranon.


What type of fixation method(s) are best for fractures due to avulsion?

Tension bands - secured with a couple of pins & cerclage wire, resist avulsion force. Together with muscles, the wire generates downward force of compression.


What causes an intra-capsular or peri-capsular fracture? Give some examples.

Major & Minor types - a fracture at the epiphysis occurs at the articular surface/joint.


- Carpal fracture or fragment (Salter I-VI)

-fractures can start from metaphyseal region and extend through physis down to articular surface (Salter IV)

Most concerning are Salter  V& VI (not shown), which occur along the line of physis & can lead to physeal growth problems/uneven growth of distal limbs, ie., limb deformity

- slow-growing ulna physis restricts growth of radius caudally & laterally → abnormally bowed radius

- shortened & bent tibia


What are the main fixation methods you would use for an intra-articular or peri-articular fracture?

Normally open reduction with internal fixation (ORIF) + compression (ie no callus at joint)

- occasionally removal of small chips

- occasionally conservative for non-weight-bearing

- if joint can’t be properly fixated, then consider

- need to stop synovial-fluid ingress into joint

- can fix fragments with lag screw


What are basic rules of application when fixing intra-articular or peri-articular fractures with open reduction and internal fixation with compression, or lag screws?

- monitor continually
- keep joints aligned
- might give it time & ideally self-healing with normal
- if equine, confine to stall, ensure good nutrition - can wait until growth ends before surgery & fix definitively in adulthood

In cases of fracture along the line of the physis, which causes slow growth and limb deformitycut slow-growing limb to relieve apposing limb & bridge overgrown-side of physis to allow slow side to catch up

- plates, screws, K-wires

- shortened tibia can be straightened & extended by
dynamic ESF (very extreme & costly)


What happens in an intra-capsular non-articular fracture? What are some examples?

This is also called a metaphyseal fracture - it occurs below the physis, away from the epiphysis, and not where the bones articulate but still within the capsule. See illustration.

- ingress of synovial fluid to fracture can cause complications

- lack of vasculature can be another complication

Examples (see illustration):

- Hip fracture ie., head of femur breaks off within acetabulum
- Ilial fracture - femoral neck fracture


What are the types of fixations used to fix an intra-capsular, non-articular fracture?

- Some can be fixated simply due to helpful force distributions

- two or three parallel orthopaedic wires or pins engage fragment; act of load-bearing causes compression (see illustration)

- plates & screws & k-wires


How does an extra-capsular non articular fracture occur, and what are some examples?

Extra-capsular non-articular fractures are fragments or fractures above or below the articular surface, and they can be metaphyseal.

Examples (see radiograph):

Neck of femur breaks but hip joint still intact

Malleolus fracture at ankle - fracture occurs proximal to joint capsule


How are extra-capsular non-articular fractures fixed for healing?

Crossed K-wires or crossed springy rush pins through fragments (see radiograph of malleolus-fracture fixation on the left).

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