Management of orthopaedic fractures Flashcards by Dean Whaley

What is an Osteogenic cell?

Bone stem cell

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What is an osteocyte?

Mature bone cell

Formed when an osteoblast becomes imbedded in secretions

Sense Mechanical strain to direct osteoclast & osteoblast activity

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What is an Osteoblast?

Bone forming
Secretes Osteoid
Catalyses mineralisation of osteoid

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What is an osteoclast?

‘Bone breaking’
Dissolve and resorb bone by phagocytosis
Derived from bone marrow

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What are Osteons?

Repeated structural units ‘Osteons’ – concentric ‘Lamellae’ around a central ‘Haversian Canal’

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What is found in compact bone?

: has osteons
Few spaces
Provides protection, support and resists stresses produced by weight of movement

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What is found in the Haversian canal?

contain blood vessels, nerves and lymphatics.

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What are the Lacunae?

small spaces containing osteocytes.

Tiny Canaliculi radiate from lacunae filled with extracellular fluid.

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What is Volkman’s canal?

– transverse perforating canals

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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

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What are the Mechanisms of Fracture?

Trauma - Low/High energy

Stress - Abnormal stress on normal bone

Pathological - Normal stress on abnormal bone

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What are the reasons for pathological fractures?

Osteoporosis - soft bone

Malignancy - Primary/Bone Metastases

Vitamin D Deficiency - Osteomalacia/Rickets

Osteomyelitis

Osteogenesis Imperfecta

Pagets

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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

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What is Wolff’s Law?

Bone Grows and Remodels in response to the forces that are placed on it

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What are the signs of a clinical fracture?

Pain 
swelling
crepitus
deformity
adjacent structural injury;
nerves, vessels, ligament, tendons

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How would you treat an extra capsular neck of femur fracture?

Internal fixation

Plate & screws or nail

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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 ```