Medical knowledge | Anatomy » Sárváry - Normal and disturbed bone healing

Normal and disturbed bone healing A.M SÁRVÁRY Semmelweis University Department of Traumatology Head: Prof.AM Sárváry Bone material * organic: osteocollagen (35%) * anorganic:hydroxylapatite (65%) Ca5 (PO4)3OH * osteocytes, osteoblasts, osteoclasts The bone is a rigide (compression-distraction), but elastic (shear-forces) material also: loading dispersion, resorption Dysplasies: -fibrotic (soft) osteogenesis imperfecta -petrosic (hard) Marmor bone disease Stability: Special macro-and microconstructions -trajectorial system -intercalar system -Havers-canals (laminae speciales) in longitudinal direction: Around 2 vessels 5-25 tubes, with perpendicular fiber-systems! -Volkmann canals (in transversal direction) are vascular connections with other Havers canals Blood supply of long tubular bones 1/3 periostal supply 2/3 endosteal supply anastomoses Anastomoses of arteria centralis • proximal aa. metaphysaria • periostal aa. • distally only end-arterias! Blood

supply of long tubular bones Nutritive artery 60Hgmm (entrance) -praecapillar artery-capillary -postcapillar vein 20 Hgmm (exit) periostal-endosteal connections Effect of reaming Bone fracture: mechanical overloading Bone healing: * primary angiogenic - contact healing - gap healing * secondary - spontaneous healing Spontaneous (secondary) bone healing Törésgyógyulás formái, zavarai 2006.0925 Secondary bone healing Conservative treatment (spontaneous healing) 1. Inflammation Posttraumatic haematoma, cellular invasion (polymorfic granulocytes, macrophages, fibroblasts on the fibrin net in the coagulum ( 1 week) 2. Soft callus In the periostal callus multiplication of connective tissue-elements. Ingrowth of capillaries, subperiostal bone production, chondroblasts at the fracture ends. Callus- fixation prevents the shortening in the fracture. ( 3 weeks ) Törésgyógyulás formái, zavarai 2006.0925 Secondary bone healing Conservative treatment (spontaneous

healing) 3. Hard callus The fracture ends are connected with hard callus Enchondral and periostal ossification starting. (6-12 weeks) 4. Remodeling Osteoclast-osteoblast activity reconstructs the original lamellar bone construction. Correction of dislocations, recanalisation of medullary canal, etc ( More months, some years) Secundary bone healing REMODELING Conservative treatment Advantages * No infection Disadvantages * no exact reduction * formal dislocations * articular contractures Methods: Plaster cast Functional/brace Extension/plaster Conservative treatment Prevention of shortening: EXTENSION Primary angiogenic bone healing contact healing - stability - fracture gap < 0,5-1 mm Plate osy. (compression) no visible callus! Primary angiogenic bone healing contact healing - stability - fracture gap < 0,5-1 mm Primary angiogenic bone healing gap healing - stability - fracture gap > 1 mm Plate osy. few visible callus gap healing -

stability - fracture gap > 1 mm gap healing 95º angled plate Intramedullary osy. Blood supply of long tubular bones 1/3 periostal blood supply 2/3 endosteal blood supply anastomoses Intramedullary osy. Intramedullary osy. Intramedullary osy. Intramedullary osy. Extra-intramedullary osy. Intramedullary osy. Unreamed Femoral Nail Trochanteric Nail Unreamed Tibial Nail Intramedullary osy. Unreamed Humeral Nail Fixateur externe Tension band Flexion: interfragmental compression Tension band Flexion: interfragmental compression Compression/lag screw DISTURBANCES OF BONY CONSOLIDATION *normal bony consolidation < 3 MONTHS *delayed healing 3 –6 MONTHS *pseudarthrosis > 6 MONTHS Absolute indication for operative treatment nonunion nonunion nonunion nonunion nonunion nonunion