لمشاهدة الفلم اضغط علي الاعلان

Internal fixation for treatment bone fractures

Fixation of bone fractures can be divided into external and internal fixations

Internal fix­ation

Definition
Are implants that are fitted directly on to or put down the inside of the bone and are then covered with soft tissues and skin ,Internal fixation can allow accurate reduction of fractures, and allows strong and stable fixation, so that the patient can rapidly return to everyday activities, with the minimum of inconvenience
Internal fixation is best performed under a tourniquet, if possible in order to obtain a blood-free view
Internal fixation requires careful preplanning and the best surgery is performed if the fractures are drawn out on stencils first, and the problems of reduction and obtaining mechanical stability planned in advance

Soft-tissue dissection should be kept to a minimum but must be adequate to obtain a clear view and access

External fixation
 Are those where the mechanical strength of the construct is outside the skin or fixation of fracture outside the skin

There are two main ways in which a fracture can be held which make a profound difference to the way in which the fracture heals

  

Rigid fixation blocks the normal callus formation of bone healing.The bone appears to be unaware that there is a frac­ture if there is no movement at the fracture site

As the bone undergoes normal physiological remodelling. the fracture cleft is gradually obliterated by new bone

This takes about a year During that time the fixation must share the loads normally taken by the bone

Most implants fatigue under the repetitive load imposed by the human body and will soon fail if the bone does not heal and take over its original function

Fracture healing is therefore a race against time: the bone must unite before the implant fails or the construct will col­lapse

• Non-rigid means of fixing (such as plaster of Paris) allow limited movement and loading of the fracture site

 The aim is to allow movement and load to stimulate callus formation without allowing the fracture to redisplace

This delicate bal­ancing act depends on the quality of the fixation the type of fracture and the compliance of the patient

Rigid versus non-rigid fixation

• Rigid fixation allows immediate loading but does not stimulate callous formation
• Non rigid fixation risks loss of reduction but stimulates rapid callus formation

Semi-rigid fixation

If the fixation of the fracture is not completely rigid then some callus will form rapidly. but the patient may be able to resume near-normal function because the fracture is held stable if not immobile by the fixation

 This partial rigidity therefore offers the best of both worlds with rapid biological healing combined with the benefits of early mobilisation of the patient

Types of Internal fixation

Screws

  

 Can be used to hold plates on to bone or can he used in their own right to hold bone fragments together

In orthopaedics, screws have been standardised to an agreed set of diameters

The threads of the screws also come in two standard forms. one for cortical and the other for cancellous bone

The size of these thread, and their pitch (the distance between each thread) are specifically designed to give the best possible grip in healthy human bone

The drills which create the holes for these screws are also standerdised allow as snug a fit of the screws as possi­ble without putting under load on the bone Taps are also sup­plied which cut the grooves in the bone to take the threads of the screws tables are available in every orthopaedic theatre to show which drill should be used for which screw

Plates and screws

• Sizes of screw and plates are now standardised

• Maximum grip is obtained without risking crocking the bone

• Nevertheless, plates must be plated on the tension side of the bone

Lagging

 
If a screw is to be used to compress two bone fragments together it is important that the thread of the screw should grip only the distal fragment in which the tip of the screw is embedded. as the screw is tightened the shoulder of the screw (the part that tapers in under the head) presses down on the proximal fragment and compresses the two fragments together. If the thread of the screw engages with the proximal fragment the screw can actually hold the fragment apart

There are techniques used to ensure that the fragments are drawn together as the screw is tightened

First a screw can be used which has no proximal thread. just a smooth shaft this known as lag screw

An alternative strategy is to use a fully threaded screw but to drill the hole in the proximal fragment to a slightly larger size so that the screw threads cannot engage with the wall of the hole

This is called lagging the drill hole and serves the same purpose as using a lag screw

Lagging

• Ensures that bone fragments are drown together as the screw is tightened

Plates

Plate, come in several sizes. each designed to be used with a stan­dard set of screws

 They are designed to fit on to the curved sur­face of bone and to be held there by screws

 The plates can be used in several ways and there are specific plate designed for each function

Use of plates

 
• They can butress,compress or neutralise plates

• In all cases their strength is in tension

• They are not good at resisting bending

Buttress plates: Buttress plates prevent one fragment of bone slip­ ping on another

They are especially useful in oblique fractures in load bearing bones, when they will stabilise what is a very unstable­ fracture configuration

Dynamic compression plates :(DCP) Dynamic compression plates have oval screw holes in them with tapered walls

If the screw holes are drilled into the bone at one end of these holes (there are drill guides to assist in doing this) then the plate slides along the bone as the screw is tightened home

If the plate has already been firmly fixed to the other fragment then the slip can be used to compress the fragments of bone tightly together

This has the ben­efit of stabilising the construct by increasing the area of contact. it also appears to stimulate healing by putting the bone edges in close apposition

Neutralisation plates :Neutralisation plates are used to prevent bone ends from being distracted

They can be used to resist angular forces by being placed on the side of a bone that goes into tension when load is applied the side that opens when the fracture bends

Plates with screws are excellent at resisting tension

 and this is how they are used in neutralisation

Plates have very little resistance to bending and so should never be put on the side of the bone that is in compression and which will go into concave angulation when load is applied

Wires

Wires are much less traumatic than plates and screws

 They can be used temporarily to hold fragments reduced while plates and screws are applied

They can also be used to resist shear where loads are not great. They are especially useful m children's frac­tures, when plates and screws could damage the epiphyseal plate

Wires can cross the growth plate without causing long-term effects and if left protruding from the skin can be removed when the fracture is secure without the need for a further surgery

The value of wires

• Can be introduced and removed percutaneously

• Safe to cross an epiphyseal plate

• Can be used as a guide for cannulated screws
Kapanji wires These are a technique which can be used in fractures in which Impaction may have left a defect that leaves the fracture unstable when reduced

After the fracture has been dis­impacted and reduced, wires are introduced into the fracture cleft on the side of the defect

 As soon as the tip of the wire is in the medulla the wire is tilted so that its tip travels proximally and embeds on the Inside of the far cortex

 One or more wires placed in this way substitute for the missing cortex and work with the intact periosteum on the other side to create a stable reduction

Figure-of-eight wiring This allows a strong wire suture to be woven over the cortex of bone which is held in tension
The device is not prominent and so fits well subcutaneously and is commonly used on the olecranon and on the patella 

Intramedullary nails

Implants driven down the medulla of a long bone sutter from a significant mechanical disadvantage because they must be narrower than the bone into which they are introduced, The resistance of an implant to bending and twisting proportional to the square of its diameter, Nevertheless, the medulla can provide a natural guide for the implant, and introducing the nail into one end of the bone (under image intensifier control) minimizes the risk of infection from opening the fracture, .and preserves the periosteal blood supply

 Nails are now available for the humerus and tibia as well as the femur

 In recent years the scope of intramedullary nails has been increased by the introduction of the locking nail
 
This system has hole through the nail at each end. using jigs or an image intensifier screw can be passed through the bone, the hole in the nail and out through the opposite cortex of the bone. This produces a construction that holds the bone rigidly,and is especially resistant to twisting it follow an intramedullary nail to be used for a far greater range of long bone fractures including those in the metaphysis some of the newer nails can now be passed down the medulla without requiring any reaming in advance the unreamed nails this makes the operation quicker and reduces the trauma to the patient

Advantages of intramedullary nails

• Now available for all major long bones

• Can be put in closed and unreamed

• Locking screws gives great stability

• Periosteal blood supply is preserved

• Patient can be mobilised early

Disadvantages and complications of internal fixation

The disadvantages of internal fixation are those of damage to soft tissues, especially blood supply

The rigidity of fixation slows the natural healing process, even though it allows earlier mobilisation of the patient

Internal fixation is technically demanding, requires a large range of implants and instruments, and is best performed in ultra clean theatres as infection is a disaster
 
This includes size and type of plates and position of screws. Only in this way can the operation be performed quickly and cleanly (minimising the risk of tissue damage and infection) so that the strongest fixation is obtained.
 There are complications inherent in using a tourniquet such as cuff damage to nerves as a result of inflation to an excessive pressure and problems of reper­fusion injury if the cuff is left inflated for too long.

Exposure of the fracture may damage the soft-tissue attachments to the bone and produce avascular fragments, which will delay or even prevent fracture union

The risk of infection can be minimised by cleaning out open
fractures and leaving them open with the fractures stabilised until it is certain that all dead and contaminated tissue has been removed

Only when they are clean should they be closed delayed primary closure

When internal fixation is used, infection is min­imised by performing quick, tidy and well-planned surgery, and by adhering to strict theatre discipline on theatre sterility
. Surgery should be covered by three doses of a broad-spectrum antibiotic which has good activity against Staphylococcus (the most common infective organism) and Streptococcus (the second most common

Internal fixation can also leave unsightly scars, and should be planned to minimise cosmetic deformity without compromising­ access

Drills and screws can damage nerves and vessels

 Drill guards should always be used to prevent soft tissues being inadvertently dragged into a spinning drill

When the drill is cutting into the far cortex, the hand that the surgeon is using to hold the drill should have a straight finger resting on the limb through which the drill is passing

Only light pressure should be applied to the drill so that when the drill then comes out through the far cortex it will not suddenly penetrate deep in the soft tissues on the far side of the bone where it might perforate a nerve or vessel .

Complications of Internal fixation

• Damage to soft tissues and blood supply

• Risk of introducing infection

•Callus formation is inhibited

Indications for removal of internal fixation

Implants for internal fixation are made of surgical-grade stainless steel and should not corrode

Nevertheless, the alloys con­tain transitional metal such as chromium and vanadium, whose salts are allergenic toxic and may even be carcinogenic

Despite this, there is little evidence that metalware left in patients for long periods causes any chemical or even allergic problems

Children should have metalware removed if it is likely to compromise growth

It should be removed as early as possible because periosteal bone grows rapidly over the plates and makes their removal difficult

 Internal fixation also shields the bone around it from load and so may cause local osteoporosis

The load passing down the bone may then peak at the end of a plate (a stress raiser) and cause a fracture

 Internal fix­ation of a fracture next to an old plate already embedded in the bone is very difficult to manage

Despite this, it is now normal practice to leave plates and even intramedullary nails in the patient unless they are causing pain or there is another specific reason for the patient to receive another general anaesthetic for another procedure
in which case plates can be removed at the same time

Reasons for removing metalwork

• Plates may load shield, producing osteoporosis

• Salts of stainless steel may be toxic in long term


tags:fixation,internal,bone,fractures,plate

BONE FRACTURES TUMORS AND DISEASES

BONE FRACTURES TUMORS AND DISEASES

This section will be including the fractures bone of the upper and lower limbs bone tumors including cancer and benign tumors and bone diseases and classification of bone fractures and how it is healed and how it is diagnosis and how it be treated and bone fractures complications

Fractures and diseases of the upper limb

• Bone physiology and structure
• Joint physiology and structure
• Muscle physiology and structure
• How fractured bone healed and union
• Clinical examination of musculoskeletal or bone diseases both upper and lower limbs
• Bone imaging for diagnosis of bone fractures diseases and tumors
• Classification of bone fractures and dislocations
• Methods of management of bone fractures and dislocations including internal bone fixation and external bone fixation
• Treatment of bone fractures by external fixation
• Treatment of of fractures by internal fixation
• Shoulder joint anatomy and function and congenital abnormalities
• shoulder joint fractures and dislocations causes types diagnosis and treatment
• Shoulder joint diseases causes types diagnosis and treatment
• Elbow joint anatomy and function
• Elbow joint dislocation
•  Elbow joint including its diseases causes types diagnosis and treatment
• Fractures and dislocations of the upper limb in children causes types diagnosis and treatment
• Fracture clavicle causes types diagnosis and treatment
• Shoulder dislocations causes types diagnosis and treatment
• Anatomy of the humors bone
• Fractures humors causes types diagnosis and treatment
• Anatomy of the radius and ulna bones
• Fractures radius and ulna causes types diagnosis and treatment including
• Galeazzi fracture
• Colles fracture
• Barton,s fracture
• Smith fracture
• Hutchinsons,s fracture
• Monteggia fracture
•  Anatomy of carpus bones
• Fractures and dislocations of the carpus or wrist bone causes types diagnosis and treatment
• Anatomy of the metacarpus and phalangeal bones
• Metacarpus and phalangeal bones fractures causes types diagnosis and treatment

Fractures and diseases of the lower limb

• Anatomy of the acetabulum

• Fractures of acetabulum causes types diagnosis and treatment
• Anatomy of the pelvic bone
• Fractures pelvis causes types diagnosis and treatment
• Anatomy of the femur bone
• Fractures femur causes types diagnosis and treatment
• Fracture neck femur
• Anatomy of the tibia and fibula
• Fractures of the tibial plateau causes types diagnosis and treatment
• Fractures tibial with or without fibular fracture
• Anatomy of the ankle joint
• Fractures and sprains of the ankle joint causes types diagnosis and treatment
• Anatomy of the tarsal metatarsal and phalangeal bones of the foot
• Fractures of the bone of the foot including the tarsal metatarsal and phalangeal bones fractures causes types diagnosis and treatment

Complications of bone fractures and dislocations
Complications of limb injury

 Bone tumors

• Malignant bone tumors causes types diagnosis and treatment
• Common malignant bone tumors causes types diagnosis and treatment
• Malignant tumors or cancer of the bone causes types diagnosis and treatment
• Benign bone tumors causes types diagnosis and treatment
• Secondary or metastatic bone tumors causes types diagnosis and treatment

Osteoarthritis

Osteoarthritis causes types

Osteoarthritis diagnosis and treatment

 

tags:fractures,tumors,bone,diseases

HOW FRACTURED BONE HEALED AND UNION

HOW FRACTURED BONE HEALED AND UNION

When the bone become fractured there are many mechanism or pathophysiology process which start after the bone become fractured to allow it to become healed as follow

When a bone break there is disruption of periosteum, cortical bone trabecular bone and the blood vessels which run in the periosteum and the medulla

There is haemorrhage and immediate release of cytokines this signals to cells locally that dam­age has occurred

 These cytokines attract macrophages, which start the clearing-up process

They also attract undifferentiated stem cells, which migrate in and start differentiating into fibroblast and bone -producing cells

These stem cells probably come from the periosteum and the endosteum, and normally lie latent

The haematoma around the fracture is invaded with small
capillaries while the macrophages remove the haematoma itself

 At the same time connective tissue is laid down the connec­tive tissue slowly organises

 This pattern of layers of organised tissue appear, first as a collar arising from the periosteum close to the end of each broken bone

The collars appear to grow towards the collar on the other bone Eventually, the spurs of callus meet and bridge the fracture site

   They become increasingly thick, and strong fibrocartilage stabilises the fracture. this period, which in the adult occurs over the first few weeks after the fracture, is described as the fracture becoming sticky

It may still be possible to angulate the fracture but it is no longer possible to translate the fracture (move it from side to side

Meanwhile in the fracture cleft Itself, osteoclasts con­tinue to resorb haematoma and other dead tissue and to eat away the broken bone ends

This can result in the fracture becoming more obvious on radiographs over the first few weeks and, indeed, can make visible fractures that were initially invis­ible (e.g. the scaphoid

 The callus of fibrous cartilage around the fracture cleft becomes calcified and then ossified (so that it is visible on radiographs

 Ossification starts not at the bone ends but in the centre of the fracture cleft, where oxygen lev­els may be very low

 Cartilage may be laid down initially rather than bone this cartilage is then replaced by bone (endochondral­ ossification).  the callus is either derived from the haematoma or from the periosteum by movement stimulates the production of a callus.

When the fracture can no longer be angulated with normal
loads, and it is not painful to try, the fracture is said to be clinically united

On radiographs, when the Strands of ossified callus can be seen to be stretching continuously from one bone end to another the fracture is said to be radologically united , in neither case is the fracture at full strength yet, but at this stage limited activity can be undertaken safe

 Finally, the callus forms a fat cuff of woven bone from one bone end to the other

This callus is at least as strong as the bone around it, because it has widened the diameter of the tube and this confers extra strength

This stage is called consolidation Over the next months the woven bone is replaced by Haversian cortical bone which remodels over the following years, until it is almost impossible 

to see where the fracture was in the bone

HOW YOU CAN DETERMINING UNION OF BONE FRACTURES

 
Types of bone union

• Clinically:united pain free to pressure not full strength

• Radiologically :united bone cross the fracture cleft

• Consolidatiaon :osteoblastic activity has returned to near normal or full strength

Clinical union

A bone is clinically united when putting load on the fracture produces no detectable movement and no pain

The fracture site will not yet be as strong as the bone around it, but it is united

Radiological union

This is not the same as clinical union

 It occurs when the callus around the fracture can be seen to pass from one broken bone end to the other without a gap between

 The fracture across the medulla of the bone may still be visible, but the callus around the bone is continuous

 The bone should now be able to cope with normal loads but will not be as strong as the bone around it

 From a management point of view, it is the time when movement and loading of the limb should be increased to build up muscle power, mobility and proprioception

 If the patient plays sport or works in a job involving heavy labour he or she should not return to this unless the bone is protected or until the fracture has consolidated 

Consolidation

Consolidation takes much longer than union

 And is defined as the time when the process of fracture healing is complete and the strength of the bone has risen to normal levels or even beyond

The formation of callus around a fracture creates a strong cuff The diameter of this cuff is greater than the diameter of the bone itself, and so a consolidated fracture can be stronger than 

the orig­inal bone

tags:fractured,healed,bone,union,how

EXPLAINING EXTERNAL FIXATION OF BONE FRACTURED

 

EXPLAINING EXTERNAL FIXATION OF BONE FRACTURED

There are two types of bone fixation

Internal fixation and external fixation

 Internal fixation see here

 
External fixation

Are those where the mechanical strength of the construct is outside the skin or fixation of fracture outside the skin

Is an alternative way to holding a fracture is to insert pins and wires into the bone on each side of the fracture, and to attach these to an external frame that provides the structural integrity

 Fixators can be as simple as a set of pins incorporated into a plaster through single- and double-bar fixators or as complex as ring fixators holding the bone through tension wires

There is a trade-off between cost, ease of fitting, adjustability rigidity and convenience to the patient

The choice of fixator will depend on what is available and the use to which it is to be put

 The llizarov fixator tensions wires onto an external ring ,wires are easy and safe to introduce, tend not to get infected and are then very strong in tension

Advantages of external fixation

• Minimally invasive

• Can be used when soft tissue cover is compromised

• Allows early mobilisation

• Can be adjusted later

Uses of an external fixator

Emergency use of the external fixator especially in fracture pelvis

Fixators are used for two main reasons in an emergency
Pelvic fractures They can be used to stabilise an unstable pelvic fracture to try to reduce life-threatening haemorrhage from the pelvic veins

 Closing and stabilising an open pelvis fracture may reduce bleed­ing by reducing movement of the pelvic veins this may stabilize clots and reduce haemorrhage

Closing the pelvis may increase the intrapelvic pressure and tamponade the veins to reduce bleed­ing

A bar fixator attached to pins inserted into the pelvic wings will need to be used The bar should be set as low as possible to give enough room over the abdomen should a laparotomy be needed

Neurovascular compromise

 
If a limb has an unstable fracture and has lost its blood supply the skeleton needs to be stabilised before the vascular repair can be performed one option is to insert a stent and provide a temporary blood supply to the limb while a definitive orthopaedic fixation is performed an alternative is to use an external fixator that can be applied quickly to stabilise the
fracture

So that the vascular surgeon can start work with the min­imum of delay

 The disadvantage of this approach is that an exter­nal fixator may not be the optimal way of stabilising that particular fracture, but once it has been applied the risk of infec­tion from the pin tracks makes a conversion to a plate or an intramedullary nail potentially risky.

Non-emergency use of the external fixator

Soft-tissue damage If there is extensive damage to the soft tissues then it may not be possible to achieve good cover of the bone

 If bone is contaminated and/or exposed internal fixation may not be advisable, in these circumstances an external fixator may offer the best option

The position of the pins can be planned with the plas­tic surgeons to enable them to rotate flaps without the fixator or the pins getting in the way

Leg lengthening and correction of deformity

  

 It is one of the great advances in orthopaedics has been the discovery that bones can be lengthened gradually

Callostasis Segments of bone can be moved across defects and, if the periosteum is left as intact as possible, new bone will be laid down in the defect - bone transport

In order for the pins of the fixator to be able to move through the soft tissues as the bones move they need to be very thin, and it is now routine to use wires which gain their rigidity by being tensioned on a ring by the Ilizarov technique

 The key to the tech­nique is to move the bone so slowly that new bone can be laid down in its track, but not so slowly that the bone unites and prevents any further distraction

 The fixation pins must be positioned to avoid damaging vital structures as they carve through the soft tissues

Care must also be taken to avoid overstretching nerves and vessels, and to avoid contractures caused by liga­ments, tendons and muscles failing to extend in concert with the bone

tags:external,bone,fixation,explaining,fractured

ALL YOU NEED ABOUT INTERNAL FIXATION OF FRACTURED BONE

ALL YOU NEED ABOUT INTERNAL FIXATION OF FRACTURED BONE

Types of fixation

Fixation can be divided into external and internal fixations

 Internal fix­ation

Are implants that are fitted directly on to or put down the inside of the bone and are then covered with soft tissues and skin
  
,Internal fixation can allow accurate reduction of fractures, and allows strong and stable fixation, so that the patient can rapidly return to everyday activities, with the minimum of inconvenience
  
Internal fixation is best performed under a tourniquet, if possible in order to obtain a blood-free view


Internal fixation requires careful preplanning and the best surgery is performed if the fractures are drawn out on stencils first, and the problems of reduction and obtaining mechanical stability planned in advance

Soft-tissue dissection should be kept to a minimum but must be adequate to obtain a clear view and access

External fixation
 Are those where the mechanical strength of the construct is outside the skin or fixation of fracture outside the skin

There are two main ways in which a fracture can be held which make a profound difference to the way in which the fracture heals

  

Rigid fixation blocks the normal callus formation of bone healing.The bone appears to be unaware that there is a frac­ture if there is no movement at the fracture site

As the bone undergoes normal physiological remodelling. the fracture cleft is gradually obliterated by new bone

This takes about a year During that time the fixation must share the loads normally taken by the bone

Most implants fatigue under the repetitive load imposed by the human body and will soon fail if the bone does not heal and take over its original function

Fracture healing is therefore a race against time: the bone must unite before the implant fails or the construct will col­lapse

• Non-rigid means of fixing (such as plaster of Paris) allow limited movement and loading of the fracture site

 The aim is to allow movement and load to stimulate callus formation without allowing the fracture to redisplace

This delicate bal­ancing act depends on the quality of the fixation the type of fracture and the compliance of the patient

Rigid versus non-rigid fixation

• Rigid fixation allows immediate loading but does not stimulate callous formation
• Non rigid fixation risks loss of reduction but stimulates rapid callus formation

Semi-rigid fixation

If the fixation of the fracture is not completely rigid then some callus will form rapidly. but the patient may be able to resume near-normal function because the fracture is held stable if not immobile by the fixation

 This partial rigidity therefore offers the best of both worlds with rapid biological healing combined with the benefits of early mobilisation of the patient

Types of Internal fixation

Screws

  

 Can be used to hold plates on to bone or can he used in their own right to hold bone fragments together

In orthopaedics, screws have been standardised to an agreed set of diameters

The threads of the screws also come in two standard forms. one for cortical and the other for cancellous bone

The size of these thread, and their pitch (the distance between each thread) are specifically designed to give the best possible grip in healthy human bone

The drills which create the holes for these screws are also standerdised allow as snug a fit of the screws as possi­ble without putting under load on the bone Taps are also sup­plied which cut the grooves in the bone to take the threads of the screws tables are available in every orthopaedic theatre to show which drill should be used for which screw

Plates and screws

• Sizes of screw and plates are now standardised

• Maximum grip is obtained without risking crocking the bone

• Nevertheless, plates must be plated on the tension side of the bone

Lagging

 
If a screw is to be used to compress two bone fragments together it is important that the thread of the screw should grip only the distal fragment in which the tip of the screw is embedded. as the screw is tightened the shoulder of the screw (the part that tapers in under the head) presses down on the proximal fragment and compresses the two fragments together. If the thread of the screw engages with the proximal fragment the screw can actually hold the fragment apart

There are techniques used to ensure that the fragments are drawn together as the screw is tightened

First a screw can be used which has no proximal thread. just a smooth shaft this known as lag screw

An alternative strategy is to use a fully threaded screw but to drill the hole in the proximal fragment to a slightly larger size so that the screw threads cannot engage with the wall of the hole

This is called lagging the drill hole and serves the same purpose as using a lag screw

Lagging

• Ensures that bone fragments are drown together as the screw is tightened

Plates

Plate, come in several sizes. each designed to be used with a stan­dard set of screws

 They are designed to fit on to the curved sur­face of bone and to be held there by screws

 The plates can be used in several ways and there are specific plate designed for each function

Use of plates

 
• They can butress,compress or neutralise plates

• In all cases their strength is in tension

• They are not good at resisting bending

Buttress plates: Buttress plates prevent one fragment of bone slip­ ping on another

They are especially useful in oblique fractures in load bearing bones, when they will stabilise what is a very unstable­ fracture configuration

Dynamic compression plates :(DCP) Dynamic compression plates have oval screw holes in them with tapered walls

If the screw holes are drilled into the bone at one end of these holes (there are drill guides to assist in doing this) then the plate slides along the bone as the screw is tightened home

If the plate has already been firmly fixed to the other fragment then the slip can be used to compress the fragments of bone tightly together

This has the ben­efit of stabilising the construct by increasing the area of contact. it also appears to stimulate healing by putting the bone edges in close apposition

Neutralisation plates :Neutralisation plates are used to prevent bone ends from being distracted

They can be used to resist angular forces by being placed on the side of a bone that goes into tension when load is applied the side that opens when the fracture bends

Plates with screws are excellent at resisting tension

 and this is how they are used in neutralisation

Plates have very little resistance to bending and so should never be put on the side of the bone that is in compression and which will go into concave angulation when load is applied

Wires

Wires are much less traumatic than plates and screws

 They can be used temporarily to hold fragments reduced while plates and screws are applied

They can also be used to resist shear where loads are not great. They are especially useful m children's frac­tures, when plates and screws could damage the epiphyseal plate

Wires can cross the growth plate without causing long-term effects and if left protruding from the skin can be removed when the fracture is secure without the need for a further surgery

The value of wires

• Can be introduced and removed percutaneously

• Safe to cross an epiphyseal plate

• Can be used as a guide for cannulated screws

Kapanji wires These are a technique which can be used in fractures in which Impaction may have left a defect that leaves the fracture unstable when reduced

After the fracture has been dis­impacted and reduced, wires are introduced into the fracture cleft on the side of the defect

 As soon as the tip of the wire is in the medulla the wire is tilted so that its tip travels proximally and embeds on the Inside of the far cortex

 One or more wires placed in this way substitute for the missing cortex and work with the intact periosteum on the other side to create a stable reduction

Figure-of-eight wiring This allows a strong wire suture to be woven over the cortex of bone which is held in tension
The device is not prominent and so fits well subcutaneously and is commonly used on the olecranon and on the patella 

Intramedullary nails

Implants driven down the medulla of a long bone sutter from a significant mechanical disadvantage because they must be narrower than the bone into which they are introduced, The resistance of an implant to bending and twisting proportional to the square of its diameter, Nevertheless, the medulla can provide a natural guide for the implant, and introducing the nail into one end of the bone (under image intensifier control) minimizes the risk of infection from opening the fracture, .and preserves the periosteal blood supply

 Nails are now available for the humerus and tibia as well as the femur

 In recent years the scope of intramedullary nails has been increased by the introduction of the locking nail
 
This system has hole through the nail at each end. using jigs or an image intensifier screw can be passed through the bone, the hole in the nail and out through the opposite cortex of the bone. This produces a construction that holds the bone rigidly,and is especially resistant to twisting it follow an intramedullary nail to be used for a far greater range of long bone fractures including those in the metaphysis some of the newer nails can now be passed down the medulla without requiring any reaming in advance the unreamed nails this makes the operation quicker and reduces the trauma to the patient

Advantages of intramedullary nails

• Now available for all major long bones

• Can be put in closed and unreamed

• Locking screws gives great stability

• Periosteal blood supply is preserved

• Patient can be mobilised early

Disadvantages and complications of internal fixation

The disadvantages of internal fixation are those of damage to soft tissues, especially blood supply

The rigidity of fixation slows the natural healing process, even though it allows earlier mobilisation of the patient

Internal fixation is technically demanding, requires a large range of implants and instruments, and is best performed in ultra clean theatres as infection is a disaster
 
This includes size and type of plates and position of screws. Only in this way can the operation be performed quickly and cleanly (minimising the risk of tissue damage and infection) so that the strongest fixation is obtained.
 There are complications inherent in using a tourniquet such as cuff damage to nerves as a result of inflation to an excessive pressure and problems of reper­fusion injury if the cuff is left inflated for too long.

Exposure of the fracture may damage the soft-tissue attachments to the bone and produce avascular fragments, which will delay or even prevent fracture union

The risk of infection can be minimised by cleaning out open
fractures and leaving them open with the fractures stabilised until it is certain that all dead and contaminated tissue has been removed

Only when they are clean should they be closed delayed primary closure

When internal fixation is used, infection is min­imised by performing quick, tidy and well-planned surgery, and by adhering to strict theatre discipline on theatre sterility
. Surgery should be covered by three doses of a broad-spectrum antibiotic which has good activity against Staphylococcus (the most common infective organism) and Streptococcus (the second most common

Internal fixation can also leave unsightly scars, and should be planned to minimise cosmetic deformity without compromising­ access

Drills and screws can damage nerves and vessels

 Drill guards should always be used to prevent soft tissues being inadvertently dragged into a spinning drill

When the drill is cutting into the far cortex, the hand that the surgeon is using to hold the drill should have a straight finger resting on the limb through which the drill is passing

Only light pressure should be applied to the drill so that when the drill then comes out through the far cortex it will not suddenly penetrate deep in the soft tissues on the far side of the bone where it might perforate a nerve or vessel .

Complications of Internal fixation

• Damage to soft tissues and blood supply

• Risk of introducing infection

•Callus formation is inhibited

Indications for removal of internal fixation

Implants for internal fixation are made of surgical-grade stainless steel and should not corrode

Nevertheless, the alloys con­tain transitional metal such as chromium and vanadium, whose salts are allergenic toxic and may even be carcinogenic

Despite this, there is little evidence that metalware left in patients for long periods causes any chemical or even allergic problems

Children should have metalware removed if it is likely to compromise growth

It should be removed as early as possible because periosteal bone grows rapidly over the plates and makes their removal difficult

 Internal fixation also shields the bone around it from load and so may cause local osteoporosis

The load passing down the bone may then peak at the end of a plate (a stress raiser) and cause a fracture

 Internal fix­ation of a fracture next to an old plate already embedded in the bone is very difficult to manage

Despite this, it is now normal practice to leave plates and even intramedullary nails in the patient unless they are causing pain or there is another specific reason for the patient to receive another general anaesthetic for another procedure
in which case plates can be removed at the same time

Reasons for removing metalwork

• Plates may load shield, producing osteoporosis

• Salts of stainless steel may be toxic in long term 

tags:need,bone,fractured,internal,fixation,all,about,you

EXPLAINING COMMON MALIGNANT BONE TUMOURS

EXPLAINING COMMON MALIGNANT BONE TUMOURS

Common primary malignant bone tumours

Are osteosarcoma , chondrosarcoma , Ewing,s sarcoma , adamantinoma , malignant fibrous histocytoma , lymphoma , myeloma

Osteosarcoma: second commonest primary malignant bone tumour, aggressive and metastasising, affecting the young

Chondrosarcoma: third commonest primary malignant bone tumour

Ewing's sarcoma: second commonest primary bone tumour in children


Adamantinoma: very rare

Malignant fibrous histiocytoma: lytic lesion needing wide resection

lymphoma: primary skeletal lymphoma is usually non-Hodgkin's. Treated by radiotherapy and chemotherapy­

Myeloma: commonest primary malignant bone tumour

Osteosarcoma

• Epidemiology: second commonest primary malignant bone tumour Bi-modal distribution
• 75% of cases in people aged 10-25
• Second smaller peak in incidence in elderly people most of whom have Paget's disease
• Aetiology: 90% idiopathic. Found in the young before epiphyseal closure. 10% secondary to underlying bone disorder (eg Paget's).Genetic basis: surviving retinoblas­toma patients have a 500-fold risk of developing osteosarcoma

• Site: most arise in medullary cavity in metaphyseal ends of long bones. Distal femur ,proximal tibia ,proximal humerus
 proximal femur pelvis

• Pathology: histology reveals malignant osteoblasts producing osteoid. Metastasis and skip lesions are common

• Presentation: painful, enlarging mass. Aggressive tumours mostly with extensive blood­ borne metastaseson diagnosis. 20% have pulmonary metastases on presentation

• Imaging: lytic or sclerotic. Extends through cortex and periosteum forming bulky mass. A triangular shadow is seen between the cortex and raised periosteum (Codman's triangle). Seldom penetrates epiphyseal plate or invades into the joint.

Spiral CT shows pulmonary metastasis in 20% of patients at presentation

• Treatment: advances in combination chemotherapy and limb-sparing surgery significantly improved survival. Resection of pulmonary metastasis is now common practice. 5-year survival rate is 75%. Prognosis is better in young adults, and in those with more distally located tumours
. Multi-focal osteosarcomas and those with a back
ground of Paget'sdisease have poor prognosis

Chondrosarcoma

• Epidemiology: third commonest primary malignant bone tumour

Affects middle-aged and elderly patients

• Aetiology: occurs de novo or as a result of malignant transformation of a previously benign cartilage tumour (eg enchondromas in Ollier's or Maffucci's syndrome

• Site: within the medulla of bone (central) or on bone surface (juxtacortical). Commonly pelvis, ribs, proximal humerus and proximal femur

• Pathology: grading determined by examining cellularity, degree of cytological atypia and mitotic activity. Most are slow growing and are of low to intermediate grade . Seldom metastasise but pulmonary metastasesare most common

• Presentation: pain or pathological fracture

• Imaging: prominent endosteal scalloping and cortical thickening. Destruction with bone expansion

• Treatment: wide surgical resection and limb salvage or amputation. Resection of pulmonary metastasis appropriate in some patients. Radiotherapy and chemotherapy not shown to be effective

• Outcome: determined by the grade of the tumour. 5-year survival rates:

• Grade 1: 90%

• Grade 2: 81%

• Grade 3: 43%


Ewing's sarcoma

• Epidemiology: 2nd commonest primary bone tumour in children. 4th commonest overall. Peak incidence in 20 years

• Site: Diaphysis of long tubular bones especially femur and flat bones of the pelvis

• Pathology: small round cells of unknown origin. 85% have characteristic chromosomal translocation between chromosomes 11 and 22

• Presentation: pain. Enlarging mass. Sometimes associated systemic upset

• Imaging: lytic lesions with permeative margins give (moth-eaten ) appearance (ie wide zone of transition). Characteristic periosteal reaction produces layers of reactive bone deposited with (onion skin) pattern

• Treatment: en bloc resection and chemotherapy Significantly improve 5-year survival rate to 75%

Primitive neuroectodermal tumour (PNET

• Essentially identical to Ewing's sarcoma in all respects except it shows more neural differentiation. Ewing's and PNET may represent different stages of differentiation of a single tumour

Adamantinoma

Very rare age 20-30 years but may occur at any age

Site :90% in tibia

Pathology: lobulated lesion mixed of fibrous and epithelial stroma

Presentation: pain and swelling slowly growing tumour history of preceding tumour are common

Imaging: lobulated lytic area with surrounding sclerotic bone

Treatment: wide resection and reconstruction or amputation

Lymphoma

Affects any age

Site :femur humerus or vertebrae

Pathology: multiple small round cells is usually non hodgkin,s lymphoma

Presentation: pain or soft tissue swelling

Imaging; moth-eaten lytic or sclerotic lesion

Treatment: radiotherapy and chemotherapy

Malignant fibrous histiocytoma

• Epidemiology: affects any age

• Site: metadiaphysis of long bones

• Pathology: consists of spindle cells, histiocyte-type cells probably derived from fibrob­lasts and giant cells. Pulmonary metastases in 30% of cases

• Presentation: pain and swelling

• Imaging: lytic lesion with permeative bone destruction (wide zone of transition). Cortical destruction and minimal periosteal reaction

• Treatment: wide resection. 5-year survival is 30-60%

Myeloma

Common bone tumour age more than 50 years

Site :any bone can be affected

Pathology :monoclonal proliferation of plasma cell B cell producing monoclonal antibody plasma electrophoresis and urine analysis for Bence-Jones protein are useful bone marrow biopsy is diagnostic

Presentation :fatigue pain and weakness

Imaging :lytic lesion with little or no reactive sclerosis typical punched out lesions

Treatment :surgery to treat or to prevent pathological fractures radiotherapy to relieve the pain chemotherapy to suppress the disease bone marrow transplant to provide cure of the disease

for more details see here

tags:common,bone,tumours,malignant,explaining

EXPLAINING OF MALIGNANT BONE TUMOURS

EXPLAINING OF MALIGNANT BONE TUMOURS

Introduction

The malignant tumours of the bones are divided into primary malignant bones tumours which arise from the bones  and these are rare tumours and secondary bones tumous which arise due to metastasis from other organs and these are commoner than primary bones tumours

Primary malignant bone tumours

The bones consists of mesenchymal tissue and the tumours of the bones may arise from bone cartilage fat fibrous tissue or endothelium

The histogenetic type of the tumour is depend on the tissue of origin

Specific types of lesions tend to occur in particular bones or area of bones as in the area of maximal growth or remodelling

 Characterized by started as single focus, pesudoencapsulation  formation of zone of reactive tissue around the expanding (lesion) they may spread along fascial planes or remains contained in anatomic compartments which include bones muscle joint skin and subcutaneous tissue and major neurovascular sheath in some cases

Causes of bones tumours

The causes of most bones tumours are unknown

Some may due to genetic mutations and chromosomal aberrations

Clinical features of bones tumours

• Pain characters of bone pain  range from dull ache to severe pain constant boring pain increase or worse at night not related to activity not respond to usual analgesic not relieved by rest in contrast to fracture pain
• Swelling or mass by bleeding into tumours may produce large swelling tumours near a joint may result in joint effusion expanding tumours more noticed early if more distal in the limb thin muscle but in hip and shoulder may obscure small tumours due to its bulky muscle
• Loss of function by neural compression (nerve root or cord) may result in loss of function pathological fractures result in acute loss of function
• Soft tissue tumours often are painless unless there is involvement of neurovascular structures
• Edema of lower limb by compression of veins or lymphatics by the tumours or metastatic invasion
• Malignant soft tissue mass can be firm and fixed to subcutaneous tissue muscle or bone 
• Local warmth is common because malignant lesions induce local (angiogenesis ) formation of new blood vessels
• Pathological fractures with bone destruction 
• Accidentally or incidentally discovers during routine examination or during investigating other problems revealed unsuspected tumours this is very important or may be  due to minor trauma which make attention of the patient or doctor to the tumours
• Systemic or general manifestations like loss of weight loss of appetite fever are very rare to present unless with metastasis

Investigations

Radiological investigations

Plain X rays radiography

• Its simple and most useful study to differentiated diagnosis of bone lesions and detect majority of bone tumours

• It should be interpreted include the following items
• Age of the patients because certain tumours predictive certain ages like ewing,s sarcoma common in children
• Site of the tumours certain tumours predictive special sites like 
• Diaphysis eg. Ewing,s sarcoma and lymphoma also benign tumour as ostoid osteoma
• Epiphysis eg, chondroblastoma and gaint cell tumour
• Metaphysis eg . osteoblastoma ,osteosarcoma,aneurysmal bone cyst fibrous dysplasia non ossifying fibtoma
• There is evidence of matrix production or no as bone formation and calcification
• Growth pattern of the tumours either permeative moth eaten loculated expansile or exophytic
• zone of transition between the normal bone and the tumor which either narrow or well marginated wide or poorly defined sharp or blurred zone
• what is bone involved eg. long bone flat bone skull vertebrae
• Presence of single or multiple lesions 
• associated soft tissue mass 
• Presence or absence of bony reaction to the tumour eg periosteal reaction sclerotic margination or bone destruction

Computerised tomography or CT scanning

• An excellent method for cross sectional examination of bone tumours
• Clear delineated the bone cortex and trabecular and bone destruction
• CT scanning of the lungs are also indicated to screen for pulmonary metastasis which are common CT scanning for abdomen to exclude metastatic disease

Magnetic resonance imaging MRI scanning

• Excellent for as soft tissue contrast
• Excellent for demonstrating tumour spread within intramedullary bone due to the presence of intramedullary fat
• It is essential for investigations of primary bone tumours

Nuclear medicine or isotope bone scanning

• Show extend of skeletal involvement but does not differentiate tumour from fracture or infection
• used to assess  response to treatment or for detection of new bone lesion

Functional nuclear scanning

• Such as positron emission tomography (PET) and Thallium scanning
• they can provide information about the biological or metabolic activity of the tumour and grade of the tumour  and also the area of tumour which either active necrotic or represent recurrent disease

Ultrasound

Useful for imaging superficial soft tissue tumours

 

Laboratory investigations

Routine laboratory studies include

• Complete or full blood count (CBC)( FBC) and differential
• Erythrocyte sedimentation rate (ESR) and C - reactive protein
• Serum alkaline phosphatase calcium and phosphate levels
• Complete urine analysis
• Complete liver function test
• Complete renal or kidney function test

Biopsy

Bone biopsy is taken to determined the nature of the tumour by taken a piece of the tumour tissue and send for histopathological  and immunohistochemical examination as follow

• True - cut needle biopsy
• Percutaneous or core needle biopsy
• Incisional biopsy if the tumour size is large

• Excisional biopsy if tumour size is small
• fine needle aspiration cytology
• Common used are True -cut needle core needle biopsy and incisional biopsy
• It should be done after imaging studies of the tumour to avoid miss interpertation of imaging study and staging of the tumour
• It is should be taken from the periphery of the tumour to avoid central or necrotic area
• Contamination of any other compartment must be avoided
• the bone biopsy cortical window should be small and oval to decrease the risk of pathological fracture

Staging of bones tumours

There are many system of staging the aim from this staging are known the anatomical extend of the tumour it is ability to causes local tissue destruction and its potential to metastasis by either clinical or pathological staging

Clinical staging

 Refers to local and systemic spread of the tumour it is established by examination and imaging studies

Pathological staging

This is based on histology and sometimes immunohistochemistry or genetics of the lesion

The Enneking surgical staging uses three parameters to give a grade from 1 to 3

 Stage IA low grade intracompartmental with no metastasis

Stage IB low grade extracompartmental with no metastasis

Stage II A  high grade intracompartmental with no metastasis 

 Stage IIB high grade extracompartmental with no metastasis
Stage III low or high grade intra or extracompartmental with distant metastasis

Tumour grade

G0  benign
G1 low grade
  G2 high grade

Treatment

   Aim to eradicate the disease  and prevent the recurrence and preserve limb function as possible 

the type treatment depend on the nature of the tumour but common include a combination of several methods as surgery chemotherapy and radiotherapy the treatment has been changed from amputation to limb salvage procedures

Non surgical treatment

• Some malignant tumours are chemosensitive or radiosensitive
• Pre-operative or neoadjuvant chemotherapy may be used with tumours like osteosarcoma and Ewing,s sarcoma to reduce the size of the tumour and make excision of the tumour easy
• Adjuvant chemotherapy has been shown to increase the survival times following resection of these tumours
• Radiotherapy is useful for control of pain and for reducing local recurrence in some tumours like myeloma lymphoma and Ewing,s sarcoma

Methods of surgical treatment

• Intralesional resection or cutettage but this will leave macroscopic remnants of tumour and it is only used for benign tumours
• Marginal resection shells out may leave microscopic remnants of the tumour used in benign tumour
• Wide resection to remove the tumour and the pseudocapsule along with the reactive zone around the tumour and removal all tumour remnants can used in low grade stage I of malignant tumour 
• Radical resection removal of the entire bone or soft tissue compartment to reduce the chance of recurrence
• Amputation if radical resection or reconstruction following radical resection is not possible amputation should be considered

New technique include computer designed prothetic implants which can replace all or part of a bone or a joint

osteochondral allograft new limb lengthening techniques and microvascular technique for free tissue transfer of bone and soft tissue

Prognosis

 Malignant bone tumour remain serious and life threatening disease the prognosis has been improved more than the past

Classification of malignant bone tuomurs

As mentioned above the bone tumours arise from the bone cartilage fat fibrous tissue and endothelium as follow

• Bone forming tumour like osteosarcoma ,paraosreal osteosarcoma, periosteal osteosarcoma, dedifferentiated osteosarcoma
• Cartilage forming tumour like chondrosarcoma ,mesenchymal chondrosarcoma, dedifferentiated chondrosarcoma ,myxoid chondrosarcoma , clear cell chondrosarcoma
• Fat forming tmour like liposarcoma
• Fibrous  or fibro-osseus tumour like fibtosarcoma ,malignant fibrous histiocytoma
• Vascular tumour like hemangioendthelioma, angiosarcoma ,hemangioperictoma
• Gaint cell tumour like malignant gaint cell tumour
• bone marrow tumour like Ewing,s sarcoma myeloma ,lymphoma of the bone , peripheral neurorpithrlioma
• Other or miscellaneous like malignant mesenchymoma , undifferentiated sarcoma, chordoma , adamantinoma , parachordoma 

Common primary malignant bone tumours

  Are osteosarcoma , chondrosarcoma , Ewing,s sarcoma , adamantinoma , malignant fibrous histocytoma , lymphoma , myeloma

For more details about these tumours see here

Secondary bone tumour see here

tags:malignant,explaining,tumours,bone