Fracture1x

Fractures Fracture Classification • Traumatic o Single injury o Multiple injuries: stress fracture • Pathological o Pre-existing bone pathology Traumatic Fracture Types • Simple (closed) o No communication between fracture and body surface • Compound (open) o Bone protrudes through body surface (medical emergency due to risk of infection) Traumatic Fracture Pattern • Transverse • Oblique • Spiral • Comminuted: multiple pieces • Crush: flat bone/vertebrae/calcaneus • Greenstick: incomplete Repeated Injury: Stress Fractures • Classic “March fractures” Pathological Fracture Classification • Inherited/ congenital o Osteogenesis imperfecta: impaired collagen synthesis, several types o Osteopetrosis: marble bone disease, osteoclastic failure o Neurofibromatosis: associated axial and long bone deformation o Gaucher’s disease: rare lysosomal storage disease, low bone mass o Enchondromatosis • Acquired: metabolic and endocrine o Osteoporosis o Diseases that lead to osteoporosis  HyperPTism Cushing syndrome: excess adrenal glucocorticoids   Hyperthyroidism Vitamin C deficiency o Osteomalacia: vitD deficiency  • Acquired: other o Paget’s Disease: abnormal bone turnover, structurally unsound o Osteomyelitis o Tumours and turnoverlike conditions  Secondary malignancy – especially metastatic carcinoma  Primary tumours – like conditions fibrous dysplasia, aneurysmal bone cyst Bone Fracture Healing Simple • Early: Healing skin wound by secondary intention o Disruption of vessels within bone, periosteum, surrounding soft tissue o Haematoma forms between fracture ends and beneath periosteum o Organisation of haematoma: ingrowth of capillaries and fibroblasts  granulation tissue o Infiltrated by neutrophils, then macrophages to remove haematoma  Intermediate: o Forming of callus (new vessels, fibrous tissue, cartilage and woven bone) o Produced from cells from periosteum and ends of fractured bone o Internal callus in original medullary cavity o Intermediate callus in cortex o External callus on surface from inner layer of periosteum o Principle cell type: osteoblasts from broken bone and periosteum o Osteoid is mineralised into woven bone with or without cartilage if poor o immobilisation or blood supply: chondroblast-like progenitor cells o Fracture ends united by provisional callus  Late: Remodelling o Partial or complete reconstruction of original bone with acquisition of full mechanical strength o o Takes months to years o Includes  Completion of mineralisation/ossification Osteoclasts remove dead bone and surplus woven bone   Osteoblasts form new bone trabeculae Lamellar orientation determined by mechanical forces acting on provisional callus o Primary union   Occasionally ends of broken bone are very close  Callus formation is minimal Other Fracture Types • Sequence of healing similar to simple fracture healing • Usually slower, more abundant callus • Attempts at repair of pathological fractures can mimic primary bone tumour e.g. extensive cartilage formation due to impaired healing vs pathological fracture due to cartilaginous tumour (chondrosarcoma) Complications of Fractures • Immediate local o Haemorrhage: life threatening if large vessel rupture o Infection: compound fracture o Tissue/organ injury: e.g. rib fracture  pneumothorax o Ischaemic bone necrosis: fracture transects arterial supply  E.g. NOF: impaired supply to femoral head • Immediate general o Fat embolism/bone marrow embolism  PE/stroke o Thrombotic embolism  PE/stroke  Remote local: o Delayed fracture union: foreign body, bone necrosis, poor blood supply, infection, poor nutritional status o Failure of fracture healing (non-union)  Soft tissue interposition  Widely separated fracture ends  Poor immobilisation  Underlying pathology e.g. neoplasm  Fragments connected to scar: ends covered by dense fibrosis, conversion to fibrocartilage  False joint: non-union  synovial cavity forms in fibrous tissue  Osteoarthritis: line of fracture through hyaline cartilage which fails to repair  Complications of chronic osteomyelitis: infected compound fracture, discharging sinus, secondary malignancy • Remote general o Osteoarthritis in joints distant from fracture site Abnormal weight bearing, poor realignment of fracture bone o Systemic complications secondary to chronic osteomyelitis e.g.   Amyloidosis  Metastatic abscess