Tissue Repair: Fracture PDF

Tissue Repair: Fracture DPT 581: Medical Management I Spring 2025 Tissue Repair: Bone Cortical bone: tough, dense outer layer, 80% of bone Cancellous/trabecular bone: spongy, thin plates, 20% of bone I...

Tissue Repair: Fracture DPT 581: Medical Management I Spring 2025 Tissue Repair: Bone Cortical bone: tough, dense outer layer, 80% of bone Cancellous/trabecular bone: spongy, thin plates, 20% of bone Injury result of: ○ Trauma- fracture ○ Infection ○ Infarction ○ Adverse response to prosthesis ○ Inflammatory conditions ○ Tumors ○ Metabolic conditions ○ Systemic conditions Bone Cells Involved in Tissue Repair Osteoblasts ○ Produce bone matrix & initial mineralization of periosteum & endosteum Osteoclasts ○ Phagocytic bone cells ○ Resorb bone Osteocytes ○ Detect local mechanical loading ○ Signal osteoblasts to initiate remodeling Osteoprogenitor cells ○ Stem cells that develop into osteoblasts Tissue Repair: Fracture Hemostasis: formation of fracture hematoma ○ Brings fibroblasts, platelets and osteoprogenitor stem cells Inflammatory phase (weeks 2-6): Fibrin scaffold between ends of fracture Reparative phase (weeks 6-12): Bone growth factors ○ Callus forms and transforms via Endochondral Ossification Soft callus (days to 3 weeks)- granulation tissue & fibrocartilage Hard callus (2 -12 weeks)- osteoblasts ○ Bridging on radiograph- evidence of healing Remodeling phase (months to years) ○ Woven bone → lamellar bone: increases stability ○ Excessive callus reabsorbed by osteoclasts ○ Mechanical stress facilitates remodeling Tissue Repair: Fracture Classification of Fractures Complete, incomplete Displaced vs. Non-Displaced Number of pieces (Comminuted) Open vs. closed Salter-Harris classification for pediatrics Timeline for Fracture Healing Normal Conditions Children: 4-6 weeks Adolescents: 6-8 weeks Adults: 10-18 weeks Abnormal Conditions Malunion Nonunion Case courtesy of Mostafa Elfeky, Radiopaedia.org, rID: 82571 Types of Fracture 1. Traumatic Fracture 2. Stress or Fatigue Fracture 3. Insufficiency Fracture 4. Pathologic Fracture Fatigue Fracture Normal bone subjected to repeated abnormal stress ○ Tibia, MTPs, femoral neck, spine 2 Types: ○ Compressive- running, marching, gymnastics ○ Distractive- result of muscle pull (throwing, golf) Fatigue Fracture Population: long-distance runners, soldiers Risk: female athlete triad, poor muscle endurance, sedentary lifestyle with recent change in activity Symptoms: painless at first ○ Progress to pain during activity → constant pain Imaging: often bone scan ○ If radiograph (-) Treatment: immobilization, activity modification Insufficiency Fracture Normal stress, abnormal bone density ○ Osteoporosis Common in vertebra ○ Thoracic vertebral body compression fracture Symptoms: respiratory issues, decreased height, sharp pain Risk: Radiation, menopause, metabolic Imaging: radiograph, CT scan Treatment: Postural correction, resistance training, bracing Pathologic Fracture Bone abnormally fragile due to disease process ○ Cancer: metastasis most common ○ Also primary bone lesions, benign lesions, metabolic disorders Activation of osteoclasts: weakens bone Most common at femoral head & neck, spine, pelvis Management of Fractures Severity of injury dictates intervention ○ Unstable, displaced, comminuted, open- require surgery Common surgical intervention: ○ Open Reduction Internal Fixation (ORIF) ○ Joint Arthroplasty Conservative Treatment: ○ Casting, immobilization ○ Possible limited WBing ○ Physical Therapy  Effects of Immobilization Tissue Result Muscle Atrophy, decreased strength, contracture Bone Osteopenia Tendon/ligaments Disorganization of parallel cells, increased deformation with standard load or compression Ligament Insertion site Ligaments not attached to bone, reduced load to failure Cartilage Adherence of connective tissue to cartilage; decreased thickness Meniscus Adhesions of synovium, decreased synovial fluid Joint 0-12 weeks: decreased ROM, increased intra- articular pressure 12 weeks+:force required for flexion/extension increases more than 12-fold Errors in Healing Process Result Risk Decreased bone mineralization Fracture Inappropriate collagen Tendinopathy Scar tissue Muscle contracture Decreased tensile strength Fibrosis Increased osteoblasts Heterotopic Ossification Myositis Ossificans Heterotopic Ossification/ Myositis Ossificans Formation of bone in non-skeletal tissue Occurs after burns, trauma, surgery, or injury to the CNS Interventions: ○ NSAIDs ○ Radiation therapy ○ Surgery ○ Conservative care PROM & gentle self-stretch Avoid aggressive stretching