General Principles of Fractures

Question 1

Define dislocation

Answer 1

Complete loss of contact between articular surfaces of a joint.

Question 2

Define subluxation

Answer 2

Some contact, but no longer congruous

Question 3

What is required for bone to heal?

Answer 3

Intact fracture haematoma and controlled micro-movement

Question 4

Name the 4 stages of bone healing

Answer 4

Inflammation

Soft callus

Hard callus

Remodelling

Question 5

What is present in a fracture haematoma? and what stage of the fracture healing is it present?

Answer 5

Stage 1: Inflammation

Fibrin clot

Polymorphs

Platelets

Monocytes

Later: Fibroblasts, osteoprogenitor cells, vascular ingrowth

Question 6

Describe the soft callus

Answer 6

Bony fragments united by fibrous or cartilaginous tissue

Both ends no longer freely movable, though angulation is still possible

Question 7

Describe the hard callus

Answer 7

Mineralisation of cartilage

Osteoblasts convert cartilaginous tissue → woven bone

External callus

Question 8

Name indications for internal fixation (5 in total)

Answer 8

Displaced intra-articular fractures

Fractures with tenuous blood supply

Multiple injuries

More than one fracture in single limb

Pathological of long bones

Question 9

What is the classic triad for fat embolism?

Answer 9

Respiratory

Neurological

Petechial Rash

Question 10

What is compartment syndrome and what are the signs?

Answer 10

Muscle swelling within a closed osseo-fascial compartment → increased pressure → capillary ischaemia and death

Signs:

Pain on passive stretch of muscle

Pain out of proportion to injury

Pins and needles, pulselessness are signs but manifest too late

Question 11

What would the radiographs show for delayed union?

(two marks)

Answer 11

Bone resorption

Restricted/poor quality callus

Malunion or non-union are typical for the tibia which is bad at healing (extra-osseus blood supply)

Question 12

Define Hypertrophic non-union and how would you treat it?

Answer 12

Inadequate stability but bone ends viable → excessive callus

Treatment: Achieve stability

Question 13

Define atrophic non-union and how would you treat it?

Answer 13

No evidence of cellular activity → both ends narrow rounded and porotic

Treatment: remove fibrous tissue from both ends up to healthy bone, rigid stabilisation, graft area around fracture

Question 14

Define a pathological fracture

Answer 14

Fracture occuring following minimal stress through abnormal bone

Question 15

How do you treat open fractures?

Answer 15

Within 6 hours:

Thorough/repeated debridement

Skeletal stabilisation

WIthin 72 hours:

Early skin cover and rehabilitation after

Question 16

Define the following fractures:

Greenstick

Buckle

Plastic deformity

Physeal injury

Answer 16

Greenstick = angulated, intact inner side of curve

Buckle = bump in bone

Plastic deformity = like plastic ruler bending, remains bent after force removed

Physeal injury = fracture through zone of provisional calcification, growing cells remain with epiphysis (Salter Harris 2 most common)

Question 17

What are the differences between adult and child bone?

Anatomically

In terms of the periosteum

Biomechanically

Answer 17

Anatomically = bone may heal curved, but will eventually straighten - remodelling ability

Periosteum = thick, metabolically active

Biomechanically = increased collagen:mineral content, more porous and elastic

Also ligaments are stronger than bone, so physis is a weak link

Question 18

How would you treat an intra-articular fracure that is displaced?

Answer 18

Open reduction, as it is intra-articular, the joint surface requires repairing to reduce risk of secondary OA.

Also stable fixation to allow early movement to eliminate joint stiffness

Question 19

How would you treat a pubic ramus fracture that is minimally displaced?

Answer 19

Does not require reduction if minimally displaced. Pelvic ring is stable for retention.

Symptomatic treatment and early mobilisation is appropriate.