Management of orthopaedic fractures Flashcards
What is an Osteogenic cell?
Bone stem cell
What is an osteocyte?
Mature bone cell
Formed when an osteoblast becomes imbedded in secretions
Sense Mechanical strain to direct osteoclast & osteoblast activity
What is an Osteoblast?
Bone forming
Secretes Osteoid
Catalyses mineralisation of osteoid
What is an osteoclast?
‘Bone breaking’
Dissolve and resorb bone by phagocytosis
Derived from bone marrow
What are Osteons?
Repeated structural units ‘Osteons’ – concentric ‘Lamellae’ around a central ‘Haversian Canal’
What is found in compact bone?
: has osteons
Few spaces
Provides protection, support and resists stresses produced by weight of movement
What is found in the Haversian canal?
contain blood vessels, nerves and lymphatics.
What are the Lacunae?
small spaces containing osteocytes.
Tiny Canaliculi radiate from lacunae filled with extracellular fluid.
What is Volkman’s canal?
– transverse perforating canals
What is the structure of long bones?
Periosteum – Connective tissue covering
Outer Cortex – compact bone
Cancellous bone
Medullary cavity - contains yellow bone marrow
Nutrient Artery
Articular cartilage: on surface of bone at a joint only
What are the Mechanisms of Fracture?
Trauma - Low/High energy
Stress - Abnormal stress on normal bone
Pathological - Normal stress on abnormal bone
What are the reasons for pathological fractures?
Osteoporosis - soft bone
Malignancy - Primary/Bone Metastases
Vitamin D Deficiency - Osteomalacia/Rickets
Osteomyelitis
Osteogenesis Imperfecta
Pagets
What are Fracture patterns
Is the soft tissue intact? yes - closed no - open Is the break complete? yes 2 pieces - simple yes >2 pieces - comminuted no - greenstick
Are the bony ends aligned?
Yes - undisplaced
No - displaced
What is Wolff’s Law?
Bone Grows and Remodels in response to the forces that are placed on it
What are the signs of a clinical fracture?
Pain swelling crepitus deformity adjacent structural injury; nerves, vessels, ligament, tendons
How would you treat an extra capsular neck of femur fracture?
Internal fixation
Plate & screws or nail
How would you treat an intracapsular displaced Neck of femur fracture?
Displaced - less than 55 reduce and fixation with screws.
older than 65, if fit and mobile total hip replacement. less fir hemiarthroplasty
Undisplaced - Fixation with screws
How do we classify joints?
Fibrous - Sutures, Syndesmosis, Interosseous membrane
Cartilaginous - Synchondroses (spine), Symphses (pubic).
Synovial - Plane, Hinge, Condyloid, Pivot, Saddle, Ball & socket.
How are synovial joint stabilised?
muscles/tendons
ligaments
Bone surface congruity
What are the components of a synovial joint?
Synovium - 1-3 cell deep lining containing macrophage-like phagocytic cells (type A synoviocyte) and fibroblast-like cells that produce hyaluronic acid (type B synoviocyte)
Type I collagen
Synovial fluid - Hylauronic acid rich viscous fluid
Articular cartilage - Type 2 collagen, Proteoglycan (aggrecan)
What is cartilage composed of?
1) specialized cells (chondrocytes)
2) extracellular matrix: water, collagen and proteoglycans
(mainly aggrecan)
Cartilage is avascular – it has no blood supply
What is Aggrecan?
- a proteoglycan that possesses many chondroitin sulfate and keratin sulfate chains
- characterized by its ability to interact with hyaluronan (HA) to form large proteoglycan aggregates
What are the 2 major types of joint disease?
Osteoarthritis
Inflammatory arthritis
What are the radiological changes in rheumatoid arthritis?
Joint space narrowing
Osteopenia
Bony erosions
What are the radiological changes in Osteoarthritis?
Joint space narrowing
Subchondral sclerosis
Osteophytes
What is the pathophysiology of Osteoarthritis
Degenerative disease of chondral cartilage
Inflammation occurs late in disease cf. rheumatoid
Inflammatory mediators include proteinases, e.g., matrix metalloproteinases (MMPs) and aggrecanases, and inflammatory cytokines, including interleukin (IL)-1β and tumor necrosis factor α (TNFα), which enhance the synthesis of proteinases and other catabolic factors to degrade the articular cartilage membrane
What is the definition for osteoarthritis?
long-term chronic disease characterized by the deterioration of cartilage in joints which results in bones rubbing together and creating stiffness, pain, and impaired movement.
What are the risk factors for OA?
Age Excess weight gain/obesity Mechanical constraints Hereditary Female gender Osteonecrosis Leg bone malalignment Estrogen deficiency Metabolic syndrome Injury: cruciate ligament rupture, meniscectomy (surgical removal of meniscus
What is the presentation of osteoarthritis?
Pain (exertional/rest/night)
Disability: walking distance/stairs/giving way
DeformityPain (exertional/rest/night)
Disability: walking distance/stairs/giving way
Deformity
What are the assessments for OA?
Look - what’s the deformity
Feel
Move - angle of flexion
Special tests - torn ACL, Lachmanns
What is conservative management for OA?
Analgesics Physiotherapy Walking aids Avoidance of exacerbating activity Injections (steroid/viscosupplementation
What is Operative management for OA?
Replace (knee/hip) Realign (knee/big toe) Excise (toe) Fuse (big toe) Synovectomy (Rheumatoid) Denervate (wrist
What is a bone infection?
Osteomyelitis Acute or chronic Primary or secondary Pain/swelling/discharge Systemic signs: Fevers, sweats wt loss
What is a joint infection?
septic arthritis
Pain
Joint swelling/stiffness
Fevers, sweats, weight loss
What causes Septic arthritis?
Bacterial infection of a joint (usually caused by spread from the blood)
What are the risk factors for septic arthritis?
immunosuppressed, pre-existing joint damage, intravenous drug use (IVDU)
Why is septic arthritis important?
Septic arthritis is a medical emergency
-> Untreated, septic arthritis can rapidly destroy a joint
Usually only 1 joint is affected* (monoarthritis)
Consider septic arthritis in any patient with an acute painful, red, hot, swelling of a joint, especially if there is fever
How do you diagnose septic arthritis?
joint aspiration
send sample for urgent Gram stain/culture
What are common causes of Septic arthritis?
Staphylococcus aureus, Streptococci, Gonococcus*
What is the treatment for septic arthritis?
surgical wash out (lavage) & IV antibiotics
Immobilise joint in acute phase
Physiotherapy
What is the treatment for osteomyelitis?
Antibiotics: iv weeks
Surgical drainage: especially collections/sequestrum
Chronic: antibiotic suppression/dressings
??amputation
What investigations can be done in joint infections
Radiology; Plain films MRI scans: bony architecture/collections CT if MRI not available Bone scans: multifocal disease Labelled White cell scans
Bloods; CRP: acute marker ESR slower response WCC TB culture/PCR
