Fractures (Healing, assessment of healing, complications of healing, general complications of fractures, soft tissue injuries associated with fractures) Flashcards
What is the definition of a fracture?
Breakage of a bone, either complete or incomplete
What is a simple fracture?
Clean break with little damage to the surrounding tissues
What is a compound fracture?
Direct communication between the broken bone and the skin surface
What is a transverse fracture?
Fracture line is at 90o to the longitudinal axis
What is an oblique fracture?
Fracture line is usually angled by 30-45o to the longitudinal axis
What is a spiral fracture?
Fracture line is oblique and encircles portion of the shaft
What is a comminuted fracture?
Multiple bone fragments - becomes more common with age as bones ossify
What is a compression or crush fracture?
Often seen in vertebral bodies with compression of trabecular bone
What is a greenstick or incomplete fracture?
Bone is incompletely fractured with a portion of cortex and periosteum remaining intact on the compression side.
A buckle fracture is a fracture of the concave surface.
A bowing fracture is the bending of a long bone.
What is a pathological/secondary fracture?
Fracture occuring in bones weakened generally or in a localised region by disease such as metabolic, infective, neoplastic or hereditary bone disease
What are the ways in which a fracture can displace?
- Angulation - normal axis has alterted (rotated) eg dorsal/palmar, varus/valgus, radial/ulnar.
- Translocation - movement of fracture bones away from each other.
- Rotation
- Distraction/impaction.
What are the clinical features of a possible fracture?
- Swelling or bruising
- Deformity
- Pain - gets worse when the area is moved or pressure is applied.
- Loss of function
- Bone protruding from the skin
What imaging can be used to assess from fractures?
- X-ray
- CT
- MRI
What are the 5 stages of bone healing?
- Haematoma
- Organization
- Callus formation
- Enchondral Ossification
- Remodelling
What occurs in the first stage of bone healing?
Haematoma Formation
- Lacerated medullary blood vessels leak ⇒Blood rapidly coagulates
- Osteocytes near fracture surface starve (due to vessel thrombosis) -> broken ends of bone become necrotic
- Acute inflammatory response to necrotic tissue -> production of granulation tissue by fibroblasts -> formation of reparative granuloma
What occurs in the second stage of bone healing?
-
Organization - Intramembranous Ossification
- Mesenchymal cells differentiate into osteoblasts and migrate into granulation tissue
- Angiogenesis also occurs
What occurs in the Third stage of bone healing?
Callus Formation
- Primary Callus - Collagen is deposited along fibrin scaffold (new bon matrix synthesis) - osteoid from osteoblasts
- Secondary Callus - Bone formation in periosteum (woven bone) -> converts primary external callus into hard secondary callus - clinical union
What occurs in the fourth stage of bone healing?
Modelling/Enchondral ossification
- Capillary ingrowth - osteoblasts follow capillary bed
- Mineralisation of osteoid - Occurs due to osteoclast and osteoblast activity
- Bridging of fracture gap - radiological union
What occurs in the fifth stage of bone healing?
Remodelling/completion
- Woven bone is replaced by lamellar bone, according to wolffs law (form follows function)
- Under load, bone is gradually strengthened along the lines of stress
What is the sequence of bone healing?
How long does it take for haematoma and organisation to occur?
0-2 weeks
How long does it take for callus formation and modelling to occur?
3-6 weeks
How long does remodelling of bone take?
1-2 years
What host factors can impair bone healing?
- Age
- Co-morbidities - osteoporosis, infection
- Nutritional status
- Hormonal status
- Medications - steroids, NSAIDs
- Smoking
- Recent trauma
What is the rule of 3s in bone healing?
Closed, paediatric, metaphyseal, upper limb = 3 weeks
Any “complicated factor” doubles healing time - adult, dipahyseal, lower limb, open injury
What local factors influence bone healing?
- Soft tissue injury
- Bone loss
- Radiation
- Tumour
- Distraction
- Infection
- Blood supply
What is spontaneous fracture healing?
Most common mode of healing
Close together but not apposed, with intervening haematoma and variable displacement/angulation
What is contact healing of a fracture?
-
Occurs between adapted fragments - < 0.1mm between and neutralisation of interfragmentary strain
- Osteoclasts forming cutting cones ⇒ traverse the fracture line
- Accompanied by capillaries and osteoblasts - form lamellar bone ⇒ Haversian Remodelling
- NO FORMATION OF PERIOSTEAL CALLUS - if callus forms -> sign of instability (irritation callus)
What is gap healing?
- Occurs if there is a gap after internal fixation
- Haversian remodelling does not start until gap has been filled with woven bone scaffolding
- Lamellar bone is deposited perpendicular to the long axis
What problems can occur with fracture healing?
- Delayed union
- Non-union
- Malunion
- Avascular necrosis
What is delayed union?
Fracture healing takes about twice as long as expected for a specific location
Causes of delayed union
- Fracture in a bone thats finished growing, poor blood supply (eg tibia) or avascular (saphoid), infected fracture
What is non-union?
No further progress towards union within 6-9 months
Types include atrophic, hypertrophic, and infected non-union
What is atrophic non-union?
- Gap at fracture site, bone loss - soft tissue interposition or pathological bone – infection, tumour, AVN, etc
- Bone resorption due to infection or impaired blood supply
What is hypertrophic non-union?
Attempt at healing, but fracture site too mobile
- Rich in callus - elephant foot
- Poor in callus - horse hoof
What is infected non-union?
Osteomyelitis - causes unstable fixation
What is mal-union?
Fracture has healed, but not in an anatomically correct position
What is Avascular Necrosis?
Loss of blood supply, resulting in bone necrosis
What are the classic fractures that can result in avascular necrosis?
- Hip (intracapsular - #NOF)
- Scaphoid
- Talus
How do bones heal by surgical ORIF and compression?
Primary bone healing
What is an ORIF?
Open Reduction internal fixation
Open reduction” means surgery is needed to realign the bone fracture into the normal position. “Internal fixation” refers to the steel rods, screws, or plates used to keep the bone fracture stable in order to heal the right way and to help prevent infection.
What can be seen in the following radiograph?
Transverse fracture of the tibia shaft
What does the following radiograph show?
Oblique diaphyseal fracture of femur
What is the following?
Displaced spiral fracture of the proximal femoral shaft
What can be seen in the following radiograph?
Comminuted Humeral Shaft Fracture
What can be seen in the following?
Comminuted olecranon fracture
What can be seen on the following radiograph?
Greenstick fracture of distal radius
What can be seen in the following radiograph?
Greenstick fracture of the 3rd metatarsal
Early complcaitions of fratures
- Local
- Compartment syndrome
- Infection - cellulitis, osteomyelitis, sepsis
- Complex regional pain syndrome
- General
- DVT
- Fat embolus (disrupted bone marrow) Usually day 2-3
