Table of Contents

Bone or Cartilage Fracture

A Bone or Cartilage Fracture is a complete or incomplete break in the continuity of bone or cartilage. A fracture is accompanied by various degrees of injury to the surrounding soft tissues, including blood supply, and by compromised function of the locomotor system.

Classification of Fracture

Classification of Bone or Cartilage Fracture is described below-

1. Classification of Fracture based on “Casual Factors”

Direct Violence Applied to Bone: Statistics indicate that at least 75% to 80% of all fractures are caused by car accidents or motorized vehicles.

Indirect Violence: The force is transmitted through bone or muscle to a distant point where the fracture occurs (e.g., fracture of femoral neck, avulsion of tibial tubercle, fracture of condyles of the humerus or femur).

Diseases of Bone: Some bone diseases cause bone destruction or weakening to such a degree that trivial trauma may produce a fracture (e.g., bone neoplasms, nutritional disturbances affecting bone).

Repeated Stress: Fatigue fractures in small animals are most frequently encountered in bones of the front or rear foot (e.g., metacarpal or metatarsal bones in the racing greyhound).

2. Classification of Fracture based on “Presence of communicating external wound”

Fracture may be broadly classified into three typer viz. simple, compound and complicated fractures–

Simple fracture (Closed fracture) is a fracture which does not communicate with outside i.e., there is no wound on the skin leading to the fracture site.

Compound fracture (Open fracture) is a fracture which is communicating with an open wound on the skin.

Complicated fracture is a closed fracture in which there is considerable injury to important neighboring vessels or nerves or is accompanied by the opening of a joint or visceral cavity e.g., complicated fracture of rib.

3. Classification of Fracture based on “Complete or incomplete”

An incomplete fracture is a fracture which does not extend through complete thickness of the bone–

Greenstick fracture: fracture in which the bone is partially broken like a bent green stick and occurs in young animal
Partial or splintered fracture: when splinters of bone are separated from the main bone as a result of direct violence as may be caused by firearms
Fissured fracture: there is a fissure (Crack) extending through the bone without causing any displacement of fragments. The fissure in the bone may be longitudinal, transverse or oblique
Sub-periosteal (Intra-periosteal) fracture: A fracture of the cortical bone without rupture of the periosteum
Deferred fracture is an incomplete fracture in which separation of fragments occur only after a varying period after the incidence due to subsequent violence, strain or concussion

A complete fracture is a fracture in which the bone is broken completely through its thickness–

Single fracture
Double fracture
Multiple fracture (Comminuted fracture)

4. Classification of Fracture based on “Avulsion”

The tearing of bony prominence (like tuberosity) by forcible pull of its tendinous or muscular attachments. Based on the portion of the bone involved, fractures may be classified as-

Diapysary fracture: A fracture involving the diaphysis (shaft) of a long bone
Epiphysary fracture: Fracture at the junction of the epiphysis and shaft of the bone
Supracondylar fracture: A fracture above the condyle
Condyloid fracture (Condylar fracture): A fracture in which small fragments including the condyle is separated from the bone
Transcondylar fracture: A fracture of humerus or femur in which the line of fracture is at the level of condyles
Intercondylar fracture: A fracture between the condyles of the humerus
Pertrochantric fracture: Fracture of femur passing through the great trochanter
Transcervical fracture: Fracture through the neck of the femur
Periarticular fracture: When bone is fractured close to its articular extremity without extending into the joint, periarticular fracture results.
Articular fracture (joint fracture): Fracture involving the articular surface of the bone
Extracapsular fracture: a fracture near a joint but not entering within the joint capsule.
Intercapsular fracture: A fracture within the joint capsule.

5. Classification of Fracture based on “Direction of the fracture”

Depending on the direction of the fracture, a fracture may be classified as-

Transverse fracture: A fracture at right angles to the axis of the bone
Longitudinal fracture: A fracture extending in a longitudinal direction, e.g., “split pastern” in the horse, wherein there is a longitudinal fracture of the os-suffragins.
Oblique fracture: A break in a bone extending in an oblique direction
Spiral fracture: A fracture which is in a spiral direction.

6. Classification of Fracture based on “Relationship between the fragments”

Depending on relationship between the fragments in the fracture–

Torsion fracture: A fracture in which one of the fragments has been twisted and separated
Impacted fracture: Fracture in which one fragment firmly driven into another or one bone is driven into the fracture site of another, e.g., head of femur driven into a fractures acetabulum.
Dentate fracture: A fracture in which the ends of the fragments are toothed or interlocked
Riding fracture (Over-riding fracture) A fracture in which the fragments lie side side, causing shortening of the limb.
Distracted fracture: A fracture in which the fractured fragments are separated by muscular pull

7. Miscellaneous types of Fracture

A fracture could be-

Compression fracture: A fracture produced by compression, causing apparent reduction in the size of the bone due to pressure.
Depressed fracture: A fracture of skull in which a fragment is depressed blow the surface
Colle’s fracture: Fracture of distal end of radius. Abduction of paw is noticed in colle’s fracture.
Pathological fracture(spontaneous fracture; Secondary fracture) A fracture occurring due to weakening of bone by disease and not due to trauma.
Congenital (Intra-uterine) fracture: fracture of bone of a foetus in the uterus.

Fracture Healing

The healing of a Bone or Cartilage Fracture may be described in four stages-

Formation of haematoma
Formation of soft callus
Formation of primary bone callus
Formation of secondary bone callus

1. Formation of haematoma

Fracture causes injury to blood vessels and surronding soft tissue
Haemorrhage around the seat of the fracture
Haematoma (Within about 24 hours)

2. Formation of soft callus

Innergrowth of fibroblasts and capillaries (Periosteum, endosteum, Haversian canals and bone marrow)
Macrophages enters the blood clot to remove the extravasated RBC and debris
The clot contains fibrins, fibroblasts and newly formed blood vessels and resembles like granulation tissue
Soft callus or Fibrous callus or Temporary callus formation within one or two weeks

3. Formation of primary bone callus

Clot is acidic due to cellular debris consisting of damaged tissues and haemorrhage
This acidity favours mobilisation of calcium from the bone fragment as calcium phosphate and from blood
Enzyme phosphatase released from osteoclasts also cause release of calcium phosphate
Supersaturation of calcium in the haematoma at the fractured site
Calcium starts depositing and the reaction slowly turns towards alkaline – Primary bone callus forms
Osteoblasts derived from the bone fragments invade the callus(OSteoblast are more in the periosteum and endosteum and extremely few in compact bones)
Calcium deposited in the intercellular space
Mineralisation is more at the periphery and central zone of the callus and meagre in the intermediate zone
Afford temporary union and immobilises the fractured fragments
Within about four to eigh weeks depends upon the size of the bone and age, clinical union set to be happen

4. Formation of secondary bone callus

Formation of secondary bone callus and functional reconstruction of the healing bone (Formation of mature bone)-

Develops from four to eight weeks
Primary callus organised by a process of consolidation and ossification
Excessive connective tissue, cells and debris are removed by osteoclasts and new bone formation is brought about by osteoblasts
Contraction and organisation of the callus takes pace and excess thickness over the periphery disappears (Resorption)

Complications of Fracture healing

Injury of nerve causing paralysis of the muscle supplied by it cause Complications of Bone or Cartilage Fracture
Injury to important vessels causing impairment of blood supply and it may cause degeneration and atrophy the muscle
Non-union or delayed union may result from defective reduction or lack of proper immobilization
Non-union: might result if the gap between the fractured ends are very wide, interposition of soft tissue between the fractured fragments, incomplete reduction, lack of immobilization and presence of infection at the fractured site causing autolysis of the fibrin clot , thus interfering with the formation of callus.
Delayed union: caused by repeated movements interfering with the mineralization of the callus. This can usually rectified by proper and continued immobilization.