Dr. Zainab Jawad ______ Fracture and their management ______4th Stage
Fractures:-dissolution in the continuity of bone with or without displacement of fragments.
Etiology:-
Extrinsic causes:
Direct violence: trauma is the most common causes of fractures i.e. automobile injury, falling from a height
Indirect violence: bending, torsional, compression and shearing forces are transmitted in a specific fashion and produce a weak link within the bone. It may result in a fracture. Fracture of femoral neck occurs due to fall on the extended rear leg
Intrinsic causes:
Violent contraction of muscle causes avulsion fracture. Such fracture occurs frequently in immature animals
Pathologic fracture: Bony or systemic disease i.e. neoplasia, bone cyst, rickets, osteoporosis, osteomalasia and nutritional hyper- parathyroidism
Repeated stress: cause fatigue fracture
Types of fractures:
According to extent of bone damage:
Complete fracture: the bone is entirely broken in to two fragments and is generally associated with displacement of fragments
Incomplete fracture: it is common in young animals and is characterized by partial loss of continuity and displacement is minimal e.g. greenstick fracture and fissure fracture
According to displacement of the fractured fragments:
Impacted fracture: one end of broken bone is driven in to other end or one bone is driven in to the fracture side of another. Union is rapid but the bone is shortened
Distracted fracture: bone fragments are separated due to sufficient muscle pull
Depression fracture: the fragments are displaced and produce a cavity e.g. fracture of skull bone
According to severity of fracture:
Simple or closed: the fracture site does not communicate with the exterior of the body
Compound or open: the fracture site communicate with the exterior of the body
According to the direction of the fracture line:
Transverse: the fracture line is at right angle to the long axis of bone
Oblique: the line of fracture diagonal to the long axis of bone
Spiral fracture: the fracture line is spiral along the long axis of bone
Comminuted: it comprises of at least three fracture lines and all of them meet at a common point
Multiple: the bone is broken in to three or more segments and soft tissue injuries are usually severe. The fracture lines do not communicate.
Avulsion: a fragment of bone at the site of muscle insertion is detached due to it is forceful contraction
According to stability of fractured fragments:
Stable fracture: the fragments more or less interlock after reduction thus maintain the approximate length of the segment
Unstable fracture: the fracture fragments are unstable after reduction e.g. comminuted or oblique types
According to location of fracture:
Diaphyseal fracture: fracture occurs in the midshaft near the axial centre of diaphysis
Metaphyseal fracture: fracture within the anatomical metaphysis of long bone
Epiphyseal fracture: fracture of epiphysis occurs in mature animal after closure of the epiphyseal plate
Condylar fracture: fracture of the condyle either medial or lateral or both
Articular fracture: fracture involving subchondral bone and articular cartilage
Diagnosis of fracture: the fracture can be diagnosed by pain at the site of fracture, dysfunction, local trauma, abnormal posture and crepitus and most of the cases have history of injury and sudden onset of symptoms. A systematic logical approach is essential to diagnose a fracture. The points of consideration for diagnosis of fracture are:
Pain: pain over the site of fracture is common. This may be only clinical indication in incomplete fracture
Dysfunction: it is most commonly exemplified by lameness. The focal point of lameness should be located and the diagnosis pursued
Local trauma: the area of fracture is swollen and usually contusion or laceration is present in open fracture
Abnormal posture: deformity, a deviation from the normal anatomical structure may be caused by displacement of bony framework. The displacement of bone fragments in a fracture may be angular, longitudinal and rotational. It may result in abnormal mobility
Crepitus: bony crepitus is the gritting sensation transmitted to the palpation finger by the contact of the broken ends on each other. Sometimes crepitus maybe absent in case fracture ends are far apart or are interposed by soft tissue or are impacted
Radiographic signs: at least two views including joints above and below the fracture are required for radiographic diagnosis.
The radiographic signs include:-
A break in the continuity of bone
A line of radiolucency when fragments distracted
A line of radio-opacity when fragments are compressed or superimposed
Note:- all the above signs do not always occur in all fractures but combination of this signs are always present
Repair of Fracture: the rapidity of healing of a fracture is influenced by age, type of fracture, individual response and presence of systemic or local disease. In addition poor reduction, inadequate immobilization, excessive trauma or lack of aseptic procedure in surgery also interrupt or slow the healing process
The process of healing of fracture can be divided into four stages:
Stage of heamatoma
Formation of primary callus
Consolidation of callus
Resorption, replacement and remodeling
Stage of haematoma:
There is a break in continuity of bone and periosteum
The fracture is surrounded by a haematoma which may contain fragments of periosteum, bone marrow, muscles and fascia. As the blood coagulates, a mesh work of fibrin is formed
Bone cells (osteocytes, osteogenic cells) near the fracture site die
Bone cells at a distance from the fracture line continue to live
Tissues in the surrounding area undergo all the changes characteristic to inflammation in soft tissue due to trauma
Stage of formation of primary callus:
The fragments of tissues enclosed in the blood clot and dead tissue cells in the surrounding area degenerate and disintegrate and are removed by phagocytic activity
Macrophages, proliferating capillaries and fibroblasts invade the blood clots, where they produce a network of fibers or granulation tissue which form a spindle shaped cuff around the site of fracture
The pleuripotential connective tissue cells, osteogenic cells and osteoblast of the periosteum, endosteum and Haversian canals proliferate to form trabeculae of spongy bone and fibrocartilage. This trabeculae of new tissue are oriented in the pattern of a vascular tree and advance towards each other from both sides of the fracture site and unite to form the callus
The proliferation and differentiation of osteiogenic cells destined to form bone begins in periosteum, endosteum and Haversian canals within 48 hr. the proliferation of these cells resultsin the formation of cellular trabeculae which advances from each fragment into the fracture gap
The proliferating cells appear across the fracture segments
The periosteum undergoes increased thickening and advanced under the osteogenic layers
The endosteum aslo undergoes similar thickening and the trabeculae of bone advances
Pleuripotential cells at a distance from the fracture site from cartilage and fibrocartilage
Stage of consolidation: the formation of bony trabeculae (cancellous bone) directly by the osteoblasts and indirectly by the replacement of cartilage by bone (enchondral bone) results in bone union. At the completion of this stage the fragments are united
Trabeculae of bone form on outside of the shaft between the fragments (external callus)
The marrow cavity is filled and united by trabeculae of bone (internal callus)
The zone of necrotic bone are reabsorbed and replaced by living bone
Stage of resorption, replacement and remodeling:
The dead ends of the bone fragments are gradually resorbed and replaced by trabeculae of cancellous bone growing in from the external and internal calluses
The bony callus between the fragments is absorbed and replaced by compact bone. This remodeling continues until the area of union resembles mature compact bone
The medullary cavity is restored
The process of remodeling takes place over many months and it is rate of progress is influenced by all factors which influence the healing time of fractures
Biochemical and physiological changes at the site of fracture healing:
The tissue surrounding the area becomes hyperaemic shortly after the fracture
Due to hyperaemia, resorption and transfer of bone minerals from the fracture ends to the fracture haematoma fluid take place
An enzyme phosphatase, secreted by proliferating cartilage cells and osteoblasts increased in the fracture haematoma about six to eight times than normal
During first on or two weeks, the fracture haematoma is markedly acidic, then the PH returns back to the normal
Diagnosis of clinical union: clinical union is the stage in healing process when fixation devices can easily by remove. It can be confirmed by a definite evidence of a palpable callus, absence of pain on application of angulation stress and absence of movements of fragments at the fracture site; and presence of bony callus at the site of fracture as evidence by X-ray examination
Factors influencing rate of union of fracture: rate of repair of fracture is influenced by many factors
Age: union is rapid in young as compared to adult and old animals
Type of fracture: simple fracture unites early as compared to compound fractures
Site of fracture: fractures of extremities unite early than the fracture of the shaft
Injury to surrounding tissue: less injury to surrounding tissue causes early healing
Infection: the presence of infection at the site retards the rate of healing process
Distance between the fracture fragments: the two ends of fractured bone being wide apart or interposition of soft tissues between the fracture ends retard the rate of union
Stage of blood supply: a good blood supply to the fractured bone enhances fracture healing
Degree of reduction and immobilization: a good reduction and immobilization causes early union of fractured fragments
Complications of fracture: presence of infection at the fracture site, delayed and non- union, injury to major blood vessels and nerves delay healing of fractures
Hormones: thyroid hormone, calcitonin, vitamin A and D in physiological doses and anabolic steroid have been reported to enhance rate of healing. On the other hand, corticosteroids are inhibitor of fracture healing.
Principle of treatment:
Avoid unnecessary handling of the patient
Treatment of shock and hemorrhage, if present
Removal of all contaminated and devitalized tissue
Treatment of wound, if any aseptically
Reduction of the fractured fragment, if necessary, to bring the displaced fragment in close approximity as near as possible
Application of immobilization device to immobilize the reduced part to keep in position till clinical union is achieved
Methods of reduction: reduction of fracture refers to the process of replacing the fractured segments as near to their original position as possible. The chief objectives of reduction are to place fragments in perfect or satisfactory anatomical position, correct all rotational displacement and to restore alignment and proper angulation. It may be carried out in three ways
Close manipulation
Mechanical traction with or without manipulation
Open surgical approach
Complete muscle relaxation facilities reduction. This can be achieved by general anesthesia, regional or local anesthesia or by the use of muscle relaxants.
Manipulation: after determining the position of the fragments by palpation and radiography, the reduction is achieved by direct pressure or by a combination of tension and toggling. This method is used for areas of the body where the bones can be easily palpated. During manipulation care should be taken to avoid the damage to the surrounding tissue
Mechanical traction: this technique is used when muscle exert a strong displacing force. In order to overcome the muscle spasm and to bring the displaced fragments in it is original place, and counter-traction are applied.
A common method of application is to first anchor the upper portion of an appendage to the table. Then another attachment is made between the foot and the body of the surgeon and traction is applied by the surgeon on leaning backwards. Local manipulation can be done by hands to reduce the fragments. A Gordon’s extender can also be used to apply traction and counter-traction in small animals
Open approach: the fracture site is surgically exposed under strict aseptic conditions. The fragments are manipulated to bring them in apposition.
Immobilization or fixation:
Immobilization or fixation of a fracture refers to holding the fractured bone segments so that they are motionless with respect to each other. It should be rigid and uninterrupted during the healing process until clinical union is obtained. It is indicated to prevent displacement or angulation of the fragments and to prevent movement and pain
Method of immobilization:
Coaptation splints or cast
Modified Thomas split
Internal fixation
Coaptation splint or cast:
Plaster or Paris
Plastics
Impregnated gauze
Air cast
Wooden strips
Aluminum strips
X-ray film etc.
The material selected for coaptation splint or cast should be light, durable and have minimum bulk. Following point should be considered while using this type of immobilization
The hairs should not be usually clipped
Sufficient padding (cotton stockinet etc.) should be used to prevent further damage to soft tissue, nerve and circulatory system
All bony prominences should be well padded. Overpadding, should however, be avoided as it might impair immobilization
The cast or splint should fit reasonably well and should be accurately moulded to the configuration of the limb
In most cases, joints above and below the fracture site should be incorporated in the cast
After applying the cast, the reduction should be checked by radiography in two different planes
Modified Thomas splint: this is one of the widely used and adoptable splints for small animals and to some extent in large animals. This splint combines the use of limited traction and fixation and good exposure of affected part. Iron rods or duraluminum of aluminum rods in diameters of 3/16, ¼ and 3/8 of an inch are preferred. It is not ordinary used as the sole method of fixation.
It is indicated for fixation of stable fracture after reduction and to support fixation in combination with other types of fixation in joint, tendon or nerve surgery.
Internal fixation: should be used in the following cases:-
Where it is any easy, economical and assumed means for obtaining reduction, healing and good functional recovery
External fixation is not tolerated by the animal
Early ambulation of patient is required
Following methods are generally used for internal fixation:
Intramedullary pin
Steinmann pin
Rush pin
Kuntsher pin
Plates
Transfixation screws
Circumferential wires
kirschner's splint
bone grafts
complication of fracture:
infection at the fracture site: as a result of open fracture or by introduction of organism at the time of open reduction through the blood, localized osteomyelitis, hyperemia, demineralization of the fragmented ends, fibrosis resulting in to delayed union or non- union may occur
Diagnosis:- it can be done based on history, clinical symptoms and X- ray examination
Treatment:
Antibiotic (locally and systemic)
Removal of dead bone or any foreign material in the fractured area
Rigid and uninterrupted immobilization of the fractures
Delayed union and non- union:
Causes:-
Imperfect apposition; interposition of soft tissue, stripping of periosteum
Impairment of blood supply
Lack of blood clots between fragments
Infection of bone
Distraction of bone fragments
Osteoporosis
Heavy dose of steroid
Reaction to plates and screw
Functional disuse
Tool early motion and weight bearing
X-ray feature of delayed union:
Wide fracture line
Absence or very little presence of external and internal callus
Presence of feathery or wooly appearance of the bone and periosteum at the fracture site
X-ray feature of delayed non- union:
Rounding of the bone ends with sclerosis at the fracture site
Wide and as well defined gap between the bone fragments
Gradual bowing at fracture site, if weight bearing has been allowed
Atrophy of bone below and above the fracture site
Closure of medullary canal in each fragment
Clinical feature of non-union and delayed union:
Abnormal movement at the fracture site
False or soft tissue callus or minimal production of callus at the fracture site
Bowing at the fracture site
Varying degree of pain on using the part
Management of delayed and non- union:
Method of fixation should be critically evaluated
Inspite of rigid immobilization for a sufficient period of time, a state of non-union or delayed union still persists. Surgical measures to promote osteogenesis should be undertaken
Every effort should be made to prevent infection
Use of bone grafting should be considered
Share with your friends: |