Orthopaedics unit 5 Common fractures - deck 4

Question 1

Describe what interfragmentary compression is and what it is achieved using, for the treatment of internally fixing a fracture

Answer 1

This consists of holding two bone fragments firmly together it is usually achieved by screws or occasionally by tension band wires.

Question 2

When is the use of interfragmentary compression useful in the treatment of fractures ?

Answer 2

These achieve great accuracy and are particularly valuable in cancellous bone around joints.

They are also useful in long bones, particularly in the upper limb but in these situations extra support is required from an onlay device.

Question 3

What is an onlay device and what are they used for in the treatment of fractures ?

Answer 3

• This is a device consisting of a plate of metal
• These plates are used to support weak structures around joints and to fix long bones in the upper limb

Question 4

Can onlay devices be used in the lower limb?

Answer 4

Yes but they are generally not strong enough and certainly should not be used in the lower limb without interfragmentary compression

Question 5

What are the problems with onlay devices?

Answer 5

They inhibit natural healing by eliminating micro-movement at the fracture site due to being very rigid systems which delays healing and full load bearing despite permitting early movement of the whole leg

Question 6

What is an inlay or intermedullary device ?

Answer 6

Often an intermedullary nail which is forced into the medullary cavity of a bone to fixate it

Question 7

Why are inaly devices often very effective and what fractures are they often used for ?

Answer 7

They achieve correct alignment of the broken bones (not very accurately tho) without unduly disturbing natural bone healing

They are very strong which makes them ideal devices for treating long bone fractures, particularly in the lower limb.

Question 8

What are the disadvantages of inlay devices and what fractures does this make them unsuitable for ?

Answer 8

They are a relatively inaccurate method of restoring anatomical position and so are not useful around joints.

Question 9

If fractures are badly comminuted (fragmented) or rotated, then what can be used along with an inlay device to treat the fracture ?

Answer 9

Cross screws can be inserted in the bone using an X-ray image intensifier to show the bone and nail during surgery.

Question 10

Why is it that following fixation the bone next to a fixation device is relatively weaker?

Answer 10

As it shares the load with the fixation device and because bone is alive and adapts constantly to loads applied to it e.g. If the plate off-loads the bone then that bone gets thinner than if it were not off-loaded (Wolff’s law)

Question 11

What happens to the adjacent unsupported bone when a fracture has been internally fixated ?

Answer 11

The adjacent unsupported bone is normal - this results in a boundary is created between normal bone and weak, fixed bone leading to stresses at the abnormal/normal bone interface

Question 12

Why is it probably safer to remove implants from internal fixation of a fracture in young people ?

Answer 12

There are a number of disturbing reports of bone tumours arising around implants late after implantation which is not surprising when one considers the free ions and radicals likely to be emitted from bone implants

Question 13

What complications may arise from removal of an implant following internal fixation of a fracture?

Answer 13

• Infection
• Damage to nerves and blood vessels

Question 14

The term traction refers to both a technique used to reduce fractures and a technique used as a holdind device for fractures (note these are 2 separate techniques)

Define what traction used as holding technique is and state how it works

Answer 14

Traction as a holding technique is where a relatively small weight is applied to a limb, which exerts a pull along the axis of the broken limb.

• This pull stimulates muscles to contract.
• Muscles completely surround a bone, and this slight contraction (which is really an increase in muscle tone), is sufficient to hold a broken bone in the position achieved at reduction

Question 15

What is the max weight used to achieve a pull in the holding technique of traction ?

Answer 15

5kg

Question 16

Describe the main differences between traction used as a holding technique compared to traction used as a reduction technique

Answer 16

Traction as a holding technique - is a holding and moulding device as the muscles effectively “massage” the aligned fracture ends until natural healing takes place.

This is in direct contrast to traction in reduction where a relatively large force is used to overcome muscle resistance to achieve alignment.

Question 17

What are the 3 ways in which traction as a holding technique for fractures can be applied ?

Answer 17

1. Static
2. Dynamic
3. Balanced

Question 18

Describe the technique of static traction and give an example of it

Answer 18

• This is where the pull is applied against another part of the body, it is used for relatively short periods.
  e. g. In the Thomas splint, the pull is applied against a ring which is part of the splint which presses against the pelvis

Question 19

When is balanced traction used ?

Answer 19

where static traction is in danger of causing damage to a part of the body through pressure.

Question 20

Describe the difference between balanced and static traction

Answer 20

In balanced traction the pull against the ring (and thus the pelvis) is balanced by a weight attached to the whole splint. This takes the pressure off the skin round the ring while maintaining traction on the leg

Note thomas splint used just as in static

Question 21

Describe dynamic traction and when it is used

Answer 21

Dynamic traction is used where joints are still permitted to move but, by means of pulleys, the pull is still maintained along the line of the broken bone. In this case weights provide the pull and the counter force is achieved by tilting the bed.

Question 22

How may traction be applied ?

Answer 22

Using strapping stuck onto the skin.

Question 23

How large are the weights in traction and how long are they often applied for ?

Answer 23

• They are not large - max 5 kg
• They are applied for short periods of time - a few days

Question 24

What is the use of short-term traction particularly useful for ?

Answer 24

• When traction is being used to relieve pain, such as following a fracture of the femoral neck.
• This technique results in a change in muscle tone, relieving muscle spasm and diminishing the need for pain-killing drugs.

Question 25

For long-term traction, requiring larger weights what is traction achieved using ?

Answer 25

A pin inserted through the bone is preferable and in the long run easier to manage

Question 26

What problems can arise from the insertion of a pin in long-term traction?

Answer 26

• Loosening of the pin
• Infection

Regular nursing care of pin tracts is essential to keep them clean and dry

Question 27

What are the main uses of traction as a holding technique?

Answer 27

• Traction, apart from being a short-term pain relieving measure, is useful where other external treatment methods are problematic.
• It is frequently used for treatment of fractures of the femur where splintage to include the hip joint, although not difficult, is rather impractical, especially in the adult.
• It is also useful as an alternative to external fixation when there is a large degree of soft-tissue damage.

Question 28

What is the main problem associated with traction as a holding technique?

Answer 28

The injured person must remain in bed, making hospital stay prolonged and nursing care difficult.

Question 29

What is the remarkable thing about bone healing compared to other connective tissues ?

Answer 29

Bone tissue can be regenerated after an injury, whereas other connective tissues heal with fibrous tissue forming a scar

Question 30

What are the 5 main stages of bone healing and state the rough timeline for when each stage occurs

Answer 30

1. (inflammation) Swelling formation - first 2 weeks
2. (Soft) Callus forming - 2-6 weeks
3. (hard callus) Bone forming - 6-12 weeks
4. Bone formed - 6-12 months
5. Remodelling has taken place and the bone returns to normal - 1-2 years

Think - start counting back for ruaridh

Question 31

Does movement stimulate bone healing ?

Answer 31

Yes micromovements stimulate bone healing, but shearing forces or large movements will inhibit bone healing

Question 32

Specifically what movements stimulate bone healing ?

Answer 32

Micromovement directed along the long axis of the bone at right angles to the break

Question 33

If there is no movement at all how will bone healing differ?

Answer 33

Bone healing will occur but very slowly and by a different process, which does not involve natural external callus formation

Question 34

What is all bone healing highly dependent on?

Answer 34

A good blood supply

Question 35

What can you conclude about bone which are allowed to heal with optimal movement provided that alignment is maintained?

Answer 35

They will heal efficiently and with no long-term adverse consequences

Question 36

If bones are fixed rigidly (using internal fixation techniques) how will bone healing differ than if movement is allowed?

Answer 36

They will unite in accurate alignment, but will do so slowly

Question 37

Which bones will you notice the increased healing time due to internal fixation most ?

Answer 37

This will be most marked in long bones and less problematical in cancellous bone, which tends to heal fairly quickly.

Question 38

Fractures to the shafts of long bones are usually caused by what degree of injury?

Also describe the associated tissue damage and stability of the fracture

Answer 38

• Low energy (velocity) impacts
• There is relatively little soft tissue damage and correspondingly greater fracture stability.

Question 39

What is the standard treatment for fractures to the shafts of long bones?

Answer 39

Manipulation and casting - provided holding is possible

Question 40

If holding is a difficulty in the management of a fracture to the shaft of a long bone such as in the femur for example then what method of holding may be used ?

Answer 40

• Traction
• Sometimes internal fixation

Question 41

When is internal fixation of a fracture to the shaft of a long bone which cannot be casted often justified ?

Answer 41

If this leads to early mobilisation of the injured person.

If the risk of operation is low, such as in young people and the fit middle-aged, or the benefit is high, as in the elderly, then fixation by an experienced surgeon is generally justified.

Question 42

What is the standard treatment for fractures involving the joint (intra-articular)?

Answer 42

Internal fixation as Reduction to the degree of accuracy required for intra-articular fractures is unusual without an operation.

But note that internal fixation is done if the fracture is displaced, if not then I think they would consider not doing it

Question 43

Around joints, where cancellous bone tends to be fragmented and often with little soft tissue support, holding requires accurate reconstruction of the fragments, usually with… what?

Answer 43

Screws to aid stability

Question 44

What are the most challenging types of fractures and why?

Answer 44

Ones which result from high velocity injuries because of associated damage to the blood supply

Question 45

What are the main treatments involved in the management of fractures caused by high-velocity injuries?

Answer 45

External fixators are particularly valuable in this type of injury, as outlined above, although fixation, traction and splintage all have their place.

A more detailed discussion of the management of these injuries is beyond the scope of this unit.

Question 46

Fractures should be held using fixation if it is of benefit to the injured person. Who in particular is to benefit from fixation and how?

Answer 46

Elderly people

Fixation will relieve pain and permit early mobility so preventing some of the complications caused by immobility including bedsores, chest and urinary infections and muscle wasting in these people.

Question 47

Why should pathological fractures be treated with fixation?

Answer 47

Similar reasons as to why it is fixed in the elderly

Fixation will relieve pain and permit early mobility so preventing some of the complications caused by immobility including bedsores, chest and urinary infections and muscle wasting in these people.

Question 48

Define what a pathological fracture is

Answer 48

This is when when a bone subjected to normal forces behaves abnormally by fracturing.

Question 49

A bone tumour is a common secondary tumour to maligant tumours of what ?

Answer 49

Malignant tumours of the lung, breast, thyroid and kidney

Question 50

Give some examples of occasions where fractures may be treated with internal fixation at the request of the patient

Answer 50

Imagine, as you read this, what would happen if you broke your femur playing sport just before an important wedding or an exam. Early internal fixation would of course be beneficial for early mobility.

If the surgeon is experienced and skilled and the facilities are excellent, then internal fixation is acceptable provided the injured person is properly informed and can give full consideration to the issues.