FRACTURE HEALING Dr. Nuri Aydın, Assoc. Prof. Istanbul University Cerrahpasa School of Medicine Department of Orthopedics and Traumatology nuri.aydin@istanbul.edu.tr • Fracture is a break in the structural conLnuity of the bone GREEN STICK COMPLETE INCOMPLETE Normal Transverse Oblique Spiral Comminuated Avulsion Impacted Fissure GreensLck • Local Signs of Fracture – Pain and tenderness – Deformity – Swelling – Bruising – Loss of funcLon Fracture Mechanism • Single traumaLc event Fracture Mechanism • RepeteLve stress Fracture Mechanism • RepeteLve stress Periosteal reacLon No fracture seen Fracture Mechanism • Abnormal weakening of the bone – MetastaLc bone lesions – Osteoporosis • Senile • Radiotheraphy Inflamma&on Repair SoQ Callus Hard Callus Remodelling STAGES OF FRACTURE HEALING Repara&ve Phase Remodelling Phase INTENSITY OF RESPONSE Inflamma&on Phase 10% 40% 70% INFLAMMATION  Hematoma (fibrin clot)  Macrophages  Inflammatory leukocytes  Osteoprogenitor cells  HematopoieLc cells secrete growth factors GranulaLon Tissue REPAIR  Primary callus response (2 weeks)  InflammaLon triggers cell division and growth of new blood vessels (Angiogenesis) SOFT CALLUS  Chondrocytes secrete collagen and proteoglycans  Creates fibrocarLlage REPAIR  Enchondral ossificaLon  Bone formaLon  SoQ callus turns to hard callus (woven bone) HARD CALLUS Primary CorLcal Healing • Osteonal healing • Resembles normal remodelling • Occurs with rigid immobilizaLon – Plate • Anatomic reducLon Rigid ImmobilizaLon No Visible Callus Secondary CorLcal Healing • Enchondral healing • Closed treatment – Cast • There is movement at the fracture site Periosteal Bridging Callus callus REMODELLING • Begins during the middle of the repair phase • ConLnues up to 7 years • Allows the bone to assume its normal configuraLon • The stresses on the bone is important (Wolff’s Law) Bone Remodelling Cycle REMODELLING • Woven bone replaces with lamellar bone • WOLFF’S LAW – If loading on a parLcular bone increases, • the bone will remodel itself over Lme to become stronger • AdapLve changes happen at the internal architecture of the trabeculae Julius Wolff
Newborn Newborn Newborn Newborn Newborn 9 year old Date of Injury Date of Injury Date of Injury Date of Injury AQer 3 months Date of Injury AQer 3 months Date of Injury AQer 5 months Date of Injury AQer 3 months Date of Injury AQer 5 months AQer 12 months Growth Factors of Bone • Bone Morphogenic Protein (BMP) • Transforming Growth Factor-­‐beta (TGF-­‐β) • Insulin-­‐Like Growth Factor II (IGF-­‐II) • Platelet-­‐Derived Growth Factor (PDGF) Growth Factors of Bone • Bone Morphogenic Protein (BMP) – OsteoinducLve Mesenchymal cells Osteoblasts • Transforming Growth Factor-­‐Beta (TGF-­‐β) – Induces mesenchmal cells and osteoblasts to produce type II collagen – Regulates carLlage and bone formaLon in fracture callus What influence Fracture Healing? • Biologic Factors – Age – Comorbid medical condiLons – FuncLonal level – NutriLonal status – Nerve funcLon – Vascular Injury – Health of soQ Lssue envelope – Sterility (open fractures) – Smoking – Extent of Bone Loss • Mechanical Factors – SoQ Lssue aiachments to bone – Stability – Anatomic locaLon – Level of energy imparted Endocrine Effects on Fracture Healing Effect Mechanism Growth hormone + Increased callus volume TH/PTH Bone remodelling + Calcitonin +? Unknown Cor&sone -­‐ Decreased callus proliferaLon Systemic Factors Ultrasound and Fracture Healing • Increases mechanical strength of callus • Mechanical energy is transmiied to the cells RadiaLon and Fracture Healing • Decreases the cellularity • Reduces structural integrity Electricity and MagneLc Fields • There are charged molecules on bone and carLlage • Electrical sLmulaLon alters a variety of cellular acLvity • SLmulate bone healing 2011
Healing • StaLc magneLc field increases the radiological callus in the first two weeks • PolarizaLon makes difference in results • No difference in bone mineral density THANK YOU… Dr. Nuri Aydın nuri.aydin@istanbul.edu.tr