Principles of Fractures

Question 1

Signs of a fracture?

Answer 1

Pain, tenderness, deformity
Abnormal attitude of limb
Swelling
Loss of function and inability to weight bear
+_ Nvsc compromise with concomitant soft tissue injury

Question 2

State the different causes of fracture

Answer 2

Trauma - Direct and Indirect

Stress fractures (common sites - Metatarsal, particularly the 2nd / Femoral neck / Tibia)

Pathological fractures - OMIT!

Periprosthetic

Question 3

Causes of pathological #?

Answer 3

OMIT

Osteopaenia/porosis
Metabolic bone diseases (HyperPTH/TH, OI, OP, Rickets)
Inx
Tumour

Question 4

Differentiate between metaphyseal and diaphyseal #

Answer 4

M - Healing done by ingrowth, NOT by the callus due to little movement. The metaphyses has a lot of cancellous bone, hence there is little movement. Consolidates within 3 weeks!
If there is minimal displacement and the fracture is extra-articular, can cast and allow by ingrowth
If there is displacement and intra-articular, the # needs to be stabilised and potentially filled with bone graft to fill gaps

Diaphyseal fractures have a lot more motion and perform healing by the callus

Question 5

In what scenarios are fractures an emergency?

Answer 5

• Open #
• Compartment syndrome (applies to closed systems with myocutaneous / myofascial compartments)
• Nvsc compromise
• # w haemodynamic instability, such as open book pelvic fractures (either the SIJ or the pubic ramus affected)
• Spine fractures are always emergencies.
• Polytrauma
• # / dislocation with SST compromise because could eventually become open

Question 6

Differentiate sprain, strain, and tear

Answer 6

Sprain - Painful twisting but no tearing of ligaments / capsule
Strain - May involve tearing of some fibres
Tear - Partial or complete tear

Question 7

Dislocation vs Subluxation

Answer 7

D - Complete loss of articulation at the joint. A/w anatomy, ligamentous laxity (esp for recurrent dislocations!), commonest in the shoulder and then the knee.

S - Partial loss of articular

Both managed with reduction ASAP wiht anaesthesia and muscle relaxant

Question 8

What is a Hill-Sachs lesion?

Answer 8

Osseous defect of the humeral head, typically a/w anterior shoulder instability, that leads to the lesion in the humeral head.
May lead to Bankart lesions (glenoid labrum tears anteroinferiorly because of the osseous defect.

Question 8

How do you describe an XR?

Answer 8

What views, date, patient ID
ACS MAAD

Anatomy - Which bone and where (epi/meta/diaphysis) in that bone
Complete - or Incomplete
Simple - or Comminuted

Morphology - of the fracture (transverse, oblique, spiral segmental, avulsed, impacted, torus, greenstick)

Articular(intra) - or extra?
Associated structures - soft tissue involvement / calcification / gas / foreign bodies

Displacement (best if 2 views) - Translation (Bayonet#) / Angulation with angle (i.e. apex volar angulation) / Rotation on the longitudinal axis / Changes in length with fragment separation / overlap

Can also state if open vs closed / if there are any pathological bone changes

Question 9

What is a bone scan?

Answer 9

Radioisotope scanning but only turns positive about a week after stress or undisplaced #

Question 10

Key traits of stable #?

Answer 10

Reduction -> Stays reduced with simple splint and normal movement, as inferred by XR and CEx i.e. mvmt >50% of normal range

Question 11

What makes an avulsion # unstable?

Answer 11

Muscle pull keeps fragments apart

Question 12

What makes an oblique-spiral fracture unstable

Answer 12

Complex splints are needed for reduction and holding due to translational / rotational displacement

Question 13

Outline fracture healing

Answer 13

0h - Bone breaks and haematoma forms
8h - Inflammation and cell proliferation under the periosteum (macrophages, undifferentiated stem cells, platelets surround fracture site, granulation tissue formation). Osteoclasts are also present, which is why the fracture gap is accentuated within the first few weeks

3-6w - Osteoclasts remove sharp edges (making # more visible on XR) and a fibrocartilage callus forms within the haematoma. The soft callus is cartilage

6-12w - Bone forms within the callus (endochondral calcification of cartilage). This process bridges fragments and forms woven bone. This hard callus is calcified cartilage, and allows fracture union.

6-12 MONTHS - Consolidation, as woven bone is replaced by lamellar bone

1-2y - Remodelling restores normal architecture

Question 13

Complete transverse translation will do what to the periosteum?

Answer 13

Circumferential stripping

Question 14

Bone union requires _% of bone contact and requires _ deg of angulation in long bones in kids vs adults

Answer 14

50% bone contact needed for union!

20 deg of angulation in kids , accept less in adults because of poor remodelling capacity