Fractures, Bone Healing, and Bone Pathology Lecture PDF

Fractures, bone healing and bone pathology Dr Brooke Coombes Acknowledgement of Dr Dilani Mendis Learning Objectives 1. Describe the pathophysiology and classification of fractures and bone pathologies 2. Identify factors that influence bone healing 3. Describe the principles of medical and physio...

Fractures, bone healing and bone pathology Dr Brooke Coombes Acknowledgement of Dr Dilani Mendis Learning Objectives 1. Describe the pathophysiology and classification of fractures and bone pathologies 2. Identify factors that influence bone healing 3. Describe the principles of medical and physiotherapy management of fractures, osteochondral and bone pathology Fractures and bone healing This Photo by Unknown Author is licensed under CC BY-SA What is a Fracture (#)? • Most common type of bone injury • Is a break in the structural continuity of bone tissue • Occurs due to overload that exceeds the normal range of loading to which the bone has become adapted during its growth and development What causes a Fracture? • Sudden injury – caused by direct injury eg fall, trauma Fracture of healthy bone What causes a Fracture? • Fatigue or stress fracture – repeated stress or microtrauma weakens the bone eg. Tibial stress fracture (https://www.hss.edu/orthopedic-traumacase39-leg-stress-fractures.asp) What causes a Fracture? • Pathological fracture – normal loading of bone weakened by disease (eg, tumor, osteoporosis) Pathological fractures Classification of Fractures • Classified according to: • Skin damage –open or closed • Displacement • Direction or pattern of fracture • Anatomical Location Classification of Fractures • Complete – all the way through the bone • Transverse- straight across the bone • Oblique- oblique line • Spiral – looks like a corkscrew • Comminuted – more than 2 parts Classification of Fractures • Incomplete – the whole cortex is not broken • Greenstick – the fracture is on the convex surface • Buckle (Torus)– the fracture is buckled • Salter – Harris – fractures that involve the growth plate Classification of Fractures • Example: • Closed un-displaced spiral fracture of middle left tibia What are the symptoms of a fracture? • Pain • Swelling • Deformity • Warmth, redness • Trouble using or moving the bone in a normal way Stages of fracture healing • 3-5 stages • Haematoma formation & inflammation • Fibrocartilaginous callus formation • Bony callus formation • Bone remodeling Sheen et al Fracture Healing Overview 2021 StatPearls Stages of fracture healing Haematoma formation & inflammation (Days 1-5) • Blood vessels ruptured causing a haematoma • Haematoma clots and forms a temporary framework for healing • Inflammatory cells and cytokines infiltrate • Together cells act to remove damaged, necrotic tissue and stimulate healing (Grossman & Porth 2014 Porth’s Pathophysiology: Concepts of Altered Health States) Stages of fracture healing Fibrocartilaginous callus formation (Days 5-11) • Capillary buds grow into area (angiogenesis) • Stem cells are recruited and differentiate into fibroblasts, chrondroblasts and osteoblasts • Collagen-rich fibrocartilaginous (immature) matrix layed down, spans the fracture ends Stages of fracture healing Bony callus formation (Days 11-28) • Cartilaginous callus begins to undergo ossification and calcification -> gives it rigidity • Cartilaginous callus is resorbed and replaced by immature bone • Woven bone (randomly arranged collagen) is laid down subperiosteally • At the end of this stage, a hard, calcified callus of immature bone forms Stages of fracture healing Bone remodeling (Day 18 onwards, lasting months to years) • Bony callus replaced with mature, lamellar bone (orderly deposition of collagen which is mechanically strong) • Balance between osteoclasts and osteoblasts for bone resorption & formation • Marrow cavity restored, bone contour smoothed • Reorganisation of mineralised bone along lines of mechanical stress Factors that affect bone healing • Local factors • Fracture characteristics e.g. type of fracture and size of the haematoma • • • • • Transverse fracture = small haematoma à delayed healing • Spiral fracture = larger haematoma Site – fracture healing slower in the LL than UL Infection Extent of soft tissue damage Blood supply – reduced blood supply can lead to delayed or nonunion Factors that affect bone healing • Systemic factors • Any of the following can predispose to poor healing • Advanced age, obesity, anaemia, diabetes, steroid drugs, malnutrition, smoking Average healing times of common fractures • Upper limb • Phalanges 3 weeks • Distal radius 4-6 weeks • Humerus 6-8 weeks • Lower arm 8-10 weeks • Lower limb • Metarsals 6+ weeks • Tibia 10 weeks • Femoral neck or shaft 12 weeks https://radiopaedia.org/articles/fracture-healing Complications of Fractures • Impaired Healing – Malunion/Delayed union/Non union • Avascular necrosis (AVN) • Infection • Blood clots • Fat embolism Impaired Healing • Malunion: • Healing with deformity, angulation or rotation that is visible on x-ray • Caused by inadequate reduction or alignment • Delayed union: • Failure of fracture to unite within the normal period • Eg. Spiral fractures in upper limb adults ~6 weeks to unite; in lower limb (twice as long) 12 weeks; Transverse # take twice as long Impaired Healing • Nonunion: • Failure to produce union and cessation of the processes of bone repair • Mobility at fracture site, pain on weight bearing • Can be caused by various factors eg. Malnutrition, diabetes, osteoporosis, local factors (infection, poor bone contact) Impaired Healing • Scaphoid non-union with advanced collapse https://radiopaedia.org/articles/scaphoid-non-union-2?lang=us Avascular Necrosis (Osteonecrosis) • Blood supply to a bone fragment is disrupted & the bone dies • Occurs as result of direct trauma that interrupts blood supply to bone • Common sites: femoral head, humeral head, femoral condyles • Commonly seen in a patient presenting with un-resolving pain with weight bearing post- intracapsular femoral neck fracture, talar neck fracture or scaphoid fracture Infection • Can occur when an organism colonises an area and there is an immune response by the host • Can reach bones and joints via the bloodstream or by direct invasion from a skin puncture, operation or open fracture. • Signs of infection: pain and tenderness, wound ooze, wound redness, raised temperature and occasionally confusion in the elderly population Thrombo-embolic complications • Occur when a blood clot or fat deposit obstructs blood flow • Deep Vein Thrombosis (DVT) is a blood clot • • Is a common complication of surgery, trauma (up to 60%) and inactivity • Typically occurs in the deep veins of the calf, thigh and pelvis Pulmonary embolism (PE) results when a DVT migrates throughout the circulatory system to lodge in the lung • • Occurs in up to 5% of patients with a DVT Fat embolism syndrome is the presence of fat globules in the lungs and other tissues • Occurs in about 3.5% of long bone fractures and about 10% of multitraumas Thrombo-embolic complications • Symptoms of DVT • Painful, swollen, tight, warm calf • Positive Homan’s sign could be indicative of a DVT. • Symptoms of PE presents usually 72 hours after injury • Sudden severe shortness of breath, elevated RR and HR Calf check prior to mobilising a patient or applying electrophysical agents is very important Other Complications of Fractures • Neural complications eg. Peripheral & central nerve damage, traction injury eg brachial plexus injuries, nerve compression • Respiratory complications eg. Post-op atelectasis, Pneumothorax, Pneumonia, aspiration pneumonia When is a fracture healed? • Fracture healing is a complex and continuous process • Soft callus can easily deform or bend if the fracture is not adequately supported • Hard callus is weaker than normal bone but better able to withstand external forces Dijkman J Orthop Trauma 24(3) March 2010 When is a fracture healed? • No consensus on radiographic & clinical criteria to define fracture union • Clinical union – fracture is not tender to palpation or with movement, ability to WB (~6-8 weeks) • Radiographic union – various criteria –callus size, cortical continuity, progressive loss of fracture line Dijkman J Orthop Trauma 24(3) March 2010 When is a fracture healed? • Callus formation https://radiopaedia.org/cases/fracture-healing-callus-1?lang=gb https://radiopaedia.org/articles/greenstick-fracture Children’s bones • More malleable, more likely to bend than break • Softer, but absorb more energy before breaking • Periosteum is thicker • Long bones of children have epiphyses and physes (growth plate) • Growth plate is a weak point in child’s skeleton Common types of fractures in children & adolescents • Greenstick or buckle fracture • Affects children < 10 yrs age • Salter-Harris fracture • Affects children 10-15 yrs age • Can arrest growth of bone Common types of fractures in children & adolescents • Salter-Harris fractures are classified from I to V (slipped, above, lower, through, ruined) • I – Fracture at growth plate, separates bone end from shaft • II – Fracture at growth plate and bone shaft – most common • III, IV – intraarticular, poorer prognosis orthoinfo.aaos.org Principles of fracture management https://radiopaedia.org/cases/forearm-orif?lang=us Fracture management depends on: • Open vs closed • Involvement of the joint surface • Neurovascular status of the distal extremity • Swelling and skin condition • Age – paediatric #s generally more tolerant of non-operative Mx due to significant remodeling potential Fracture management can be divided into: • Non-operative AKA conservative • Closed reduction – needed if # is significantly displaced or angulated • Immobilisation with cast or splint • Operative Indications for surgical intervention • Failed non-operative (closed) management, non-union or malunion • Unstable open #s or unstable and reduced position not maintained • Displaced intra-articular fractures (>2mm) • Large avulsion #s • Fractures known to heal poorly with non-op Mx (e.g femoral neck #) • Impending pathological fractures • Multiple trauma • #s in growth areas in skeletally immature individuals due to risk of growth arrest (e.g. Salter-Harris III-IV) Dr O’Brien PCH https://metronorth.health.qld.gov.au/ Initial management of fractures • Realignment of broken limb segment (if grossly deformed) • Immobilisation of extremity in splint • Assess neurologic and vascular status before + after • If open #, apply pressure (sterile dressing) to achieve haemostasis • Splinting is critical for symptomatic relief and preventing neurovascular or further soft-tissue injury • Adequate analgesics Operative intervention • 4 principles 1. Anatomic reduction of fracture fragments 2. Stable fixation to fulfil biomechanical demands 3. Preservation of blood supply and respect for soft tissues 4. Early range of motion and rehabilitation What is the role of physiotherapy? • Assess neurovascular integrity • Prevent complications • Pain and swelling management • Prescription of braces or mobility aids • Prescribe exercises to restore function – ROM, strength, fitness Weight bearing after lower limb fractures in adults 1. Bone has capacity to remodel and alter its architecture in response to mechanical forces acting on it • Mechanical factors influence cell proliferation and differentiation • Animal models - controlled loading leads to greater volume of callus and faster time to union compared to no loading or excessive loading 2. Elderly may not be compliant with restricted WB 3. High physiologic cost of being NWB – 4-fold increase in energy cost Kubiak J Am Acad Orthop Surg 2013; 21 Weight bearing after lower limb fractures in adults • Limited high quality evidence comparing immediate with delayed WB • Period of protected WB recommended for calcaneal, tibial plafond, tibial plateau and acetabular fractures, younger patients with hip fractures • Immediate WB associated with low complication rates for: • Surgical fixation of femoral neck # in elderly • Intramedullary nailing of femoral shaft # in younger patients Kubiak J Am Acad Orthop Surg 2013; 21 Bone pathologies This Photo by Unknown Author is licensed under CC BY-SA Bone Pathologies • Osteoporosis • Osteopenia • Osteogenesis imperfecta • Osteochondrosis Osteoporosis • Metabolic disease characterised by loss of bone mineral density (BMD) and skeletal fragility • 2-3 fold increased risk of fragility fracture • 1/3 women & 1/5 men > 50 years suffer a fracture • Osteoporosis per se is asymptomatic and most often diagnosed following fragility fracture • May present with vertebral compression, wedging and collapse, kyphosis Osteoporosis - Pathophysiology • Imbalance between bone resorption & formation causing loss of bone mineral density • Osteoporosis is the more serious progression of osteopenia foxvalleyimaging Risk factors for osteoporosis • Personal • advanced age, race, small bone structure, gender, postmenopausal, family history • Lifestyle • sedentary, calcium deficiency, nutritional status, excessive alcohol & caffeine intake, smoking • Drugs & disease • anticonvulsants, heparin, corticosteroids, diabetes mellitus, COPD, malignancy, hyperthyroidism, hyperparathyroidism, RA Diagnosis of osteoporosis • Plain radiographs not very sensitive as more than 30-50% of bone loss is required to appreciate decreased bone density on a radiograph • Thinning of cortex • Loss of trabeculae (sparce, thin & delicate) • Radiolucency • Fracture Diagnosis of osteoporosis • Dual-energy x-ray absorptiometry (DEXA) • Scan that produces 2 x-ray beams at different energy levels. It measures the amount of x-rays that pass through bone for each beam Diagnosis of osteoporosis • Dual-energy x-ray absorptiometry (DXA) • Shows how much higher or lower your bone density is than that of a healthy young adult, the age when bones are at their strongest • Osteoporosis=BMD T-score of 2.5 or more below the mean for young adult Caucasian women • Osteopenia = T-score between -1.0 and -2.5 Davidson Principles and practice of medicine 2018 Treatment of osteoporosis • Goal: Early detection and prevention of fractures • Physio: Exercise & falls prevention • Nutritional: (calcium and vitamin D supplements) • Anti-resorptive drugs (Oestrogens, bisphosphonates and calcitonin) • Surgery– stable fracture fixation Role of exercise in prevention & treatment of low BMD • Not all exercise modes are equally osteogenic • Animal studies indicate loading must • Be dynamic not static • Induce relatively high bone strains • Be applied rapidly • Short bouts separated by periods of rest best • Multidirectional ie diverse movements Beck et al JSAMS 2017 Role of exercise in prevention & treatment of low BMD • Not all exercise modes are equally osteogenic • Minimal or no effect of regular walking & low intensity activities in peri & post-menopausal women • Certain WB impact ex eg. Hopping/jumping & progressive resistance training (PRT) can improve bone health Beck et al JSAMS 2017 Role of exercise in prevention & treatment of low BMD • Not all exercise modes are equally osteogenic • Greatest benefits to spine > hip from PRT if loading is • High (80-85% of 1RM) • Twice a week • Targets large muscles crossing hip & spine • Benefits to hip > spine in of WB impact loads pre-menopausal women • >2 times body weight • 10-50 impacts/day, 3+ times/week Beck et al JSAMS 2017 Role of exercise in prevention & treatment of low BMD • Exercise programs should also include • Balance, gait training • Muscle strengthening e.g. thoracic extension • Dual task training Beck et al JSAMS 2017 Exercise goals for Low/Moderate/High risk individuals • Low risk • Asymptomatic of osteoporosis with normal BMD ie T-score above 1.0 SD, no clinical risk factors • Maximise bone mass & strength • Moderate risk • T-score -1.0 to -2.5 &/or clinical risk factors • Preserve or improve bone mass & strength, improve muscle strength, power & balance Beck et al JSAMS 2017 Exercise goals for Low/Moderate/High risk individuals • High risk • T-score less than -2.5, previous fracture or multiple risk factor • High load PRT & moderate impact loading safe & well tolerated (LiftMor study) • Supervision for technique, gradual increments Beck et al JSAMS 2017 Contraindications to exercise • If known vertebral osteoporosis/kyphosis, avoid • lifting weights with a flexed spine, sit-ups, bowling • Rapid and/or loaded twisting eg. Golf Beck et al JSAMS 2017 Osteogenesis Imperfecta • “Brittle bone disease” • Hereditary disease characterized by severe osteoporosis and multiple fractures in childhood • Defective synthesis of Type I collagen à impacts development of bones, joints, ears, ligaments, teeth & skin • Short stature Renaud (2013) Insights Imaging Osteogenesis Imperfecta • Diagnosed by clinical presentation & family history +/- genetic testing • Treatment: • Drugs – bisphosphonates to increase bone width, volume & mineral content • Prevention & treatment of fractures • Surgical intervention needed to stabilize fractures Osteochondrosis Osteochondrosis • Alteration of subchondral bone with increased risk of instability & disruption of adjacent articular cartilage • May result in premature osteoarthritis • Sites include: knees, elbows, talus (girls) • Tends to affect active children/young adults e.g. basketball, gymnasts Chau et al (2021) J Bone Joint Surg Am Osteochondrosis • Formerly termed osteochondritis dissecans (OCD) • Aetiology suggests ischemic necrosis of epiphyseal cartilage & biomechanical factors (history of mild trauma) • Patients may not recall trauma • Stable lesions can cause vague, nonspecific pain • Unstable lesions or loose bodies cause mechanical symptoms e.g. catching/locking Osteochondrosis • Conditions may be classified into three groups with many diseases in each group • Articular: e.g. Legg-Calvé-Perthes (proximal femoral head) and Kohler’s disease (navicular) • Non-articular: Osgood-Schlatter’s and Sever’s disease (tendon attachments) • Spinal: Scheuermann's disease • Role of trauma vs ischemia varies Osteochondrosis • Common stages • Necrosis of bone & cartilage • Revascularisation • Gradulation tissue invasion • Osteoclastic reorption of necrotic segments • Formation of mature bone Legg-Calvé-Perthes disease (Perthes disease) • Idiopathic osteonecrotic disease of the proximal femoral epiphysis • Affects boys more than girls (4-10 years) • Unknown cause but may be associated with acute trauma Legg-Calvé-Perthes disease (Perthes disease) • Stages involve • avascular necrosis 6-12mths • revascularisation 1-3yrs • Repair/re-ossification • healing (flattening femoral head) West (2019) Pediatric Radiology Legg-Calvé-Perthes disease • Presentation: • Painless limp • Hip, knee, or groin pain, exacerbated by hip/leg movement • Reduced range of motion at the hip joint • May be atrophy of thigh muscles from disuse and an inequality of leg length Legg-Calvé-Perthes disease • Treatment goal: to reduce deformity & preserve integrity of FH while necrotic bone is resorbed • Physiotherapy (advice & education, exercises for ROM & strength, walking aids to reduce pain & improve function) • Periods of rest/NWB • Abduction braces (maintain FH alignment) • Surgical intervention – if severe & > 6 yrs Osgood-Schlatter disease • Osteochondrosis of the tibial tubercle where the patellar tendon inserts • Affects boys>girls aged 11-15 yrs (growth period) • Is due to repetitive strain, often jumping sports • Bone ischaemia & avascular necrosis are not major features • Chronic avulsion injury during process of ossification results in abnormal bone formation at apophysis of tibial tubercle Osgood-Schlatter disease Presentation • Inflammation and thickening of the patellar tendon • Pain, swelling, tenderness, increased prominence of tibial tubercle • Radiographs may show irregularity of the apophysis with separation from tibial tuberosity and bony ossicles in later stages Osgood-Schlatter disease • Treatment: • Advice & education (Limitation/modification of activity) • Taping to deload, Braces (immobilise knee) if severe • Anti-inflammatory, application of cold • Release the tension on the quadriceps • Complete resolution of symptoms can take 1 – 2 years Scheuermann’s osteochondrosis • Condition predominantly affects adolescent boys • Irregular ossification of vertebral end plates • Vertebrae grow unevenly à "wedging" shape of the vertebrae, causing kyphosis West (2019) Pediatric Radiology Scheuermann’s osteochondrosis • Impairments: • May be asymptomatic • Thoracic back pain aggravated by exercise & relieved with rest, restricted ROM (bending backwards) • Loss of vertebral height • May have a visual 'hunchback' or 'roundback‘ • Often have an excessive lordotic curve in the lumbar spine • Often patients have tight hamstrings www.physioworks.com.au Scheuermann’s osteochondrosis • Physiotherapy Management: • Advice & education re: activity modification • Pain relief • Restoring ROM & muscle strength • Retraining for return to function through exercise QUESTIONS???