Ortho Viva-Voce

on 23.1.11 with 0 comments

What you understand by union, non-union and consolidation?

Union is an incomplete repair, as the callus en-sheathing around the site of fracture undergoes calcification.
Palpation over the site usually causes slight tenderness, but attempts of moving the bone - the bone moves as one, and attempts of angulation causes pain.
X ray reveals that the fracture line is still visible, however, there is formation of fluffy bones (callus) around the periosteum that surround the fracture site.
Since repair is incomplete, stress towards the unprotected bone is avoided.

Consolidation involves complete repair, as the callus en-sheathing around the site of fracture undergoes ossification.
Palpation over the site reveals no tenderness, non-mobile and attempts of angulation is painless.
X ray reveals that the fracture line has almost or completely obliterated.
Since repair is complete, no further protection is usually required.

Non-union is defined as arrest of bone healing process before it's completion.
It can be caused by :

a) Distraction/separation of the fracture fragments
b) Soft-tissue interposition in between the fragments
c) Poor blood supply
d) Extensive damage of soft tissue around the fracture to the extent that it becomes nearly/completely non-viable
e) Excessive movements at the fracture line

The factors above is capable of altering the cellular proliferation towards a fibroblastic type, leading to formation of predominantly fibrous tissue in between the fracture gap.
This results in false joint formation (pseudoathrosis).
Fibrous tissue will not appear in an X ray and hence, it gives an impression that there's no attempts of callus formation and bone healing, resulting in Atrophic non-union.

On the other hand, if there is too much movements at the fracture line, there'll be florid periosteal bone formation, causing the fractured end to become hypertrophic. However, due to the lack of stability, the callus formation is not sufficient to bridge the gap between the fragments, resulting in Hypertrophic non-union.
It is believed that if rigid stability is forced upon the fragments, it will eventually results in union.

Enumerate principles of management of close fracture

Principles of management of close fracture is :

Manipulative reduction of the fracture to improve their position
Hold the reduction in proper alignment until the fractured ends unite
At the time being, joint movements and function must be maintained.
Fracture healing is promoted by physiological loading and hence early exercises and weight bearing is encouraged.

a) Reduction

Of course, general treatment and resuscitation must be given first before dealing with the fracture.
However, there should not be any undue delay in dealing with the fracture, since swelling of the soft part for the next 12 hours will result in reduction becoming increasingly more difficult.

There are certain situations where reduction is not required :

1) No or minimal displacement
2) Displacement, even it happens, doesn't matter (fractured clavicle)
3) Reduction is unlikely to be successful, for eg : compression fracture of the vertebra

The aim of reduction is to achieve adequate apposition between bony fragments for optimal healing and proper alignment during the process of healing.
The more contact in between the surface area of the bony fragments, the more likely they'll unite.
Hence, a gap between the fractured end often results in non-union.
As long as there's is adequate apposition and proper alignment, even there is slight overlapping between the bony fragment, it is permissible.
This is an exception in case where fracture involving an articular surface (eg : fracture of femoral neck), where near to perfect reduction is required to prevent secondary degenerative arthritis.

Close reduction

Close reduction is done under adequate general anasthesia and muscle relaxation.
It is completed by the 3-fold maneuver :

1) Apply traction along the line of the bone.
2) As the bony fragments disengage, try reposition it by applying a force in an opposite direction to the force that causes the fracture.
3) Push the fragments into the reduced position.
4) Adjustment on all the alignments are made.

This maneuver can be achieved effectively if the muscles and periosteum over one side of the fracture is intact.
In cases where re-displacement is very likely, as in fracture of the shaft of femur (pulled by strong muscles padding around the femur), close reduction is usually not successful.

Generally, close reduction is done for fractures in children, minimally displaced fractures, fracture which after reduction is not likely to be unstable, and even unstable fractures before internal/external fixation is done.

Open reduction

Open reduction is done when :

a) Failure of close reduction, either due to difficulty in controlling the positions of the fragments or there's soft tissue interpositioned in between the fragments.

b) Traction fracture of long bones, leaving a large gap in between the bony fragments.

c) Fracture involving an articular surface, as near to perfect reduction is required.

b) Hold reduction

The word immobilisation is actually a misnomer, where the main objective is not complete immobility, but only to prevent displacement.
Examples of method where reduction is held includes : continuous traction, cast splintage, functional bracing internal and external fixation.

In situation where the damage to the soft-tissues surrounding the fracture is not severe, splintage done with closed method (non-operative) can be successful since the soft-tissues when traction is applied to it or when it is compressed, by an hydraulic effect, the fracture can be splinted successfully.

Hence, non-operative method will be a failure if there's extensive damage of the soft-tissues around the fracture. Other contraindications includes :

Unstable fractures
Multiple fractures
Fracture in a confused, non-cooperative patient

Continuous traction

Here, a traction force is applied along the bone line, to exert continuous pull over the long axis of the bone. Counter traction will be required to prevent the patient being dragged along the traction force.
It is useful for cases for eg, spiral fractures of the shaft of long bones, which are easily displaced by muscle contraction.

However, the major disadvantage of continuous traction is that it prolongs the duration of hospital stay for the patient.
Hence, continuous traction is not advisable to be done on elderly as complication associated with recumbency is though to be of higher risk (for eg : pneumonia, UTI, DVT, PE, bed sores, etc)
As for the younger population, after the fracture becomes 'sticky', the traction is usually replaced by either cast splintage or functional bracing.

Traction by gravity

This is only done is the case of upper limb injury.
For example, if there is a transverse fracture of the mid-shaft of humerus, a U-shaped bandage can be applied with a sling over the wrist.

Skin traction

In skin traction, adhesive tape is applied over the skin, and traction is applied.
The traction force shouldn't be more than 4-5 kg.

Skeletal traction

Traction is directly done through the bones where Steinmann's pin or K-wires are inserted into it and traction is applied.

Regardless whether it is skin traction or skeletal traction, continuous traction is usually done in 3 methods :

a) Fixed traction - Traction is pull on a fixed point. In case where Thomas splint is used for example, the traction cord is tied to the distal end of the splint, and the leg is pulled downward until the upper, padded ring of the splint abuts firmly against the pelvis

b) Balanced traction - Here, the traction is guided by a pulley at the foot end of bed, loaded with weight, where at the same time, counter traction is exerted by the patient's body weight as the foot end of bed is raised.

c) Combined traction - Thomas splint is usually used, where the traction cord is tied to both ends of the splint, with the splint being suspended as in balanced traction.

Category: Orthopedics Notes



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