11 - T&O General Principles

Question 1

What would be the underlying pathology in the following scenarios:

• Reduced active and passive movements
• Reduced active but full massive

Answer 1

• Joint problem
• Nerve or muscle problem

Question 2

What is the pathophysiology of OA?

Answer 2

Progressive loss of articular cartilage and remodelling of bone

Chondrocytes in articular cartilage release enzymes to break down collagen and proteoglycans destroying cartilage. Exposure of subchondral bone results in sclerosis and remodelling which causes osteophtes and subchondral bone cysts. Joint space is lost over time

Question 3

How does OA present and what are some risk factors associated with OA?

Answer 3

Most commonly in hip, knee, small joints of hands and feet

• Insidious gradually worsening pain and stiffness that is worse with activity and relieved by rest
• Deformity
• Reduced range of movement
• Crepitus

Question 4

What are some differential diagnoses for OA?

Answer 4

Always consider RA, gout, septic arthritis, fractures, bursitis and malignancy (primary and metastatic)

Question 5

How is OA investigated and managed?

Answer 5

Ix: often clinical diagnosis but can do radiographs and blood tests to rule out differentials

Conservative: weight loss, physiotherapy, heat/ice packs, joint support

Medical: simple analgesics and topical NSAIDs, intraarticular steroid injections

Surgical: osteotomy, arthrodesis, arthroplasty

Question 6

What are the 3 main principles of fracture management?

Answer 6

1. Reduce

2. Hold (plaster or surgical)

3. Rehabilatate

Question 7

What are the principles of reduction in fracture management?

Answer 7

• Restoring anatomical alignment of fracture or dislocation (see image for why)
• Usually done closed in emergency setting
• Ensure patient has sufficient analgesia (sometimes conscious sedation)
• Three people: one to perform reduction, one to provide counter traction, one to apply plaster

Question 8

What are the principles of ‘hold’ in fracture management?

Answer 8

- Consider if traction needed (when muscle pull strong across fracture site so unstable e.g subtrochanteric NOF, demoral shaft fractures)

- First 2 weeks non-circumferential plaster cast to allow swelling and not risk compartment syndrome

- If axial instability (fracture able to rotate along its long axis) then plaster should cross joint above and below. If no instability just joint distal to fracture

Question 9

What are some important safety points to consider during fracture immobilisation?

Answer 9

• Can the patient weight bear? Inform the patient
• Do they need thromboprophylaxis? Yes if non-weight bearing
• Have you given advice on the symptoms of compartment syndrome?

Question 10

What are the principles of rehabilitation in fracture management?

Answer 10

Intensive period of physiotherapy after immobilisation

Counsel patient of stiffness after cast removal and encourage patient to mobilise any non-immobilised joints from the get go

Very important in elderly patients!

Question 11

What is the process of fracture healing and how long does it take?

Answer 11

1. Haemotoma (lasts 1-2 weeks) = granulation tissue

2. Fibrocartilaginous Tissue = granulation tissue forms

3. Bony Callus (lasts 2-3 weeks) = endochondral ossification forms spongy bone. Can see callus on X-ray 2-3 weeks after injury

4. Bone remodelling (lasts months) = spongy converted to cortical bone. Bone only remodels with stressors so important not to immobilise

BONE HEALING TAKES 6-8 WEEKS ON AVERAGE

Question 12

How do the following effect fracture healing?

• External fixation
• Intramedullary nails
• Screws and plates

Answer 12

External fixation: secondary bone healing

Intramedullary nail: does not cause full rigidity so still alows some movement at fracture site. Reaming causes disruption to blood supply in inner 2/3rds of diaphysis but doesn’t stop external callus formation. Secondary bone healing

Screws and Plates: primary bone healing

Question 13

What factors contribute to non and mal-union of bone after a fracture?

Answer 13

Non-union: poor blood supply or bone instability (tobacco use, DM, obesity)

Malunion: bone not properly immobilised, having cast off to early, never having treatment for a fracture

Question 14

What bones is malunion/non-union more common in and how may this pathology present?

Answer 14

• Persistent pain at the fracture site or reduced ROM
• A persistent gap with no bone spanning the fracture site
• No progress in bone healing when repeated imaging studies are compared over several months
• Inadequate healing in a time period that is usually enough for normal healing
• May have OA if malunion occurs near a joint

Question 15

How is malunion/non-union treated?

Answer 15

Malunion:

Refracture the bone and realign with plates and screws or use a bone graft

Non-union: (FAILURE TO HEAL AFTER 9 MONTHS)

Non-surgical: US stimulator EXOGEN

Surgical: bone graft or biologics (bone morphogenic proteins)

Question 16

How does smoking affect fracture healing?

Answer 16

Nicotine can slow fracture healing by killing osteoblasts and lowering estrogen effectiveness

• Smoking can counter the antioxidant properties of vitamins C and E.
• Smoking reduces blood supply to healing fracture
• Smoking lowers calcium absorption

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Question 17

When a patient presents with an acutely swollen joint, what are some important questions to ask to rule out differentials?

Answer 17

• Establish onset, site, timeframe of swelling
• Ask about any precipitating factors (e.g trauma or surgery) and any exacerbating or relieving factors
• Find out ability to weight bear
• Ask about systemic symptoms
• Has it happened before?
• PMH and DHx

Question 18

How do you examine an acutely swollen joint?

Answer 18

• A to E assessment
• Look, feel, move
• Look for any redness, skin changes, swelling, temperature changes and compare with contralateral joint
• Check for any focal tenderness and joint effusions
• Look for other joint involvement or systemic signs

Question 19

What investigations should you do for an acutely swollen joint?

Answer 19

- Routine bloods (FBC, CRP, ESR, serum urate for gout)

- Plain film radiographs (especially if trauma)

- Joint Aspiration (look at opacity, colour and presence of frank pus then sent for WCC and microscopy)

Question 20

What are some differential diagnoses for an acute monoarthritis?

Answer 20

ALWAYS EXCLUDE SEPTIC ARTHRITIS

• Haemarthrosis
• Crystal arthropathies
• Rheumatological causes
• OA
• MSK injury
• Spondyloarthropathies (reactive arthritis, psoriatic arthritis, ankylosing spondylitis)

Question 21

Gout and Pseudogout can cause an acutely swollen joint. What are they and how are they managed?

Answer 21

Gout

• Inflammatory arthritis due to monosodium urate crystals in a joint from hyperuricemia.
• Usually in 1st MTP joint and is episodic and triggered by stress, illness and dehydration
• Diagnose with joint aspiration and microscopy
• Treat acute episode with NSAIDs
• Treat multiple episodes or extraarticular features with prophylactics like allopurinol

Pseudogout

• Due to calcium pyrophosphate crystals and often affects more proximal joints (knee and wrist)
• Risk factors of advanced age, hyperparathyroidism, hypophosphatemia

- Positively birefringent rhomboid shaped crystals

• Give NSAIDs and treat any underlying cause

Question 22

What investigations can show a swollen joint may be due to RA?

Answer 22

• Raised inflammatory markers (CRP and ESR)
• Normocytic anaemia
• RF and ACPA levels
• Plain raidiograph with LESS

Give NSAIDs, start DMARDs or biologics

Question 23

What is the diagnostic criteria for RA?

Answer 23

EULAR classification

Score of 6 or more is definite RA

Looks at joint distribution, serology, symptom duration, acute phase reactants

Question 24

What are spondyloarthropathies?

Answer 24

Group of seronegative conditions (RF negative) associated with HLA-B27

See image for list of conditions

All can present with axial arthritis or any joint and can cause enthesitis and dactylitis

Question 25

How is a haemarthrosis formed and how is it managed?

Answer 25

- Traumatic injury (e.g meniscal or ligament injury), bleeding disorders, on anticoagulants **- Ix:** routine bloods including clotting, plain film radiographs, joint aspiration **- Mx**: conservatively with RICE, analgesia and correcting any underlying coagulopathies

Question 26

What is the pathophysiology and outcomes of an open fracture?

Answer 26

- Direct communication between fracture site and external environment (includes penetration into rectum and vagina) - In-to-out or out-to-in mechanism **- Most common open:** tibial, phalangeal, forearm, ankle, metacarpal

Question 27

How are open fractures classified?

Answer 27

**Gustillo Anderson Classification** Always check neurovascular status and any evidence of contamination Identify need for plastic surgery early

Question 28

How are open fractures investigated?

Answer 28

- Bloods including clotting screen and G+S - Plain film radiograph - CT if comminuted or complex

Question 29

How are open fractures managed initially?

Answer 29

- Resuscitation and stabilisation - Urgent realignment and splinting of the limb then re-xray - Reassess neurovascular status after realignment **- Broad spectrum antibiotic cover (CO-AMOXICLAV OR MEROPENEM OR CLINDAMYCIN IF ANAPHYLACTIC P ALLERGY)** **- Tetanus vaccination** **- Photograph the wound** - Remove any gross debris and dress with saline-soaked gauze, DO NOT WASH OUT

Question 30

What is the definitive management for an open fracture?

Answer 30

**- Surgical debridement** within 12-24 hours, removing any devitalised tissue. If contaminated debride immediately **- Wash out wound** with lots of saline - Ensure **skeletal stabilisation** and if not enough soft tissue coverage ask **plastics** - If vascular compromise immediate surgical exploration by va**scular**

Question 31

What is the mangled extremity severity score?

Answer 31

Estimates **viability of an extremity** (usually lower) after trauma to determine **need for salvage versus empiric primary amputation** Looks at **age, ischaemia, mechanism of injury, shock** and doubles score if ischaemia \> 6 hours **Score of 6 or less then salvage limb!!**

Question 32

What is the pathophysiology of compartment syndrome?

Answer 32

**Causes:** high energy trauma, crush injuries, fractures with vascular injury, iatrogenic vascular injury, tight casts/splints, DVTs, post reperfusion swelling Closed fascial compartments cannot distend so fluid causes **increase in intra-compartmental pressure**. As pressure increases this **compresses the veins increasing their hydrostatic pressure** causing more fluid to move out of the veins into the interstitium Next **traversing nerves are compressed** causing **paraesthesia** and possible motor weakness Lastly when **intra-compartmental pressure reachs diastolic bp arterial inflow compromised** and **ischaemia** caused (cool, pale, pulseless, paralysed limb)

Question 33

How does compartment syndrome present?

Answer 33

- Hours to 48 hours post insult **- Severe pain disproportionate to injury** which is not improved with initial measures e.g elevation, analgesia - **Pain made worse by passive stretching** **- Paraesthesia** distally - If acute arterial insufficiency then **5 P's**

Question 34

How is compartment syndrome investigated, diagnosed and managed?

Answer 34

**_Dx:_** clinical with high suspicion for post-op **_Ix:_** intracompartmental pressure monitor, CK level **_Mx:_** - Initial management (see image) - **Urgent fasciotomy** with incisions left open for 24-48 hours - **Reassess and debride any dead tissue** - **Monitor renal function** due to risk of rhabdomyolysis or reperfusion injury

Question 35

What is ischaemia reperfusion injury?

Answer 35

**Reperfusion Syndrome** Paradoxical exacerbation of cellular dysfunction and death, following restoration of blood flow to previously ischaemic tissues

Question 36

How can a fracture cause compartment syndrome?

Answer 36

- Damage to major vessel - Oedema - Inflammation - Tight plaster cast Nerve ischaemia can be regenerated but muscle ischaemia causes fibrous replacement and scarring

Question 37

What are some risk factors for developing septic arthritis?

Answer 37

- Age \>80 - Preexisting joint disease e.g RA - DM or immunosuppression - Chronic renal failure - Hip or knee joint prosthesis - IV Drug use

Question 38

What are the main causative organisms of septic arthritis and where do they come from?

Answer 38

**Most common:** S.Aureus, Streptococcus sp, Gonorrhoea, Salmonella (especially in sickle cell) Can come from **bacteraemia** (e.g recent cellulitis, UTI, chest infection), **direct inoculation,** **spreading from adjacent osteomyelitis** Causes irreversible articular cartilage damage leading to severe OA

Question 39

What are some complications of septic arthritis?

Answer 39

- Osteomyelitis - Osteoarthritis - Septic shock

Question 40

What are the clinical features of septic arthritis and what are some differentials?

Answer 40

**- Single swollen joint with severe pain** **- Pyrexia** - Joint is **red, swollen, warm** and painful on examining movements **- Joint often rigid** and cannot tolerate passive movement, **unable to weight bear**

Question 41

How do you investigate a suspected septic joint?

Answer 41

- Routine bloods inc FBC, CRP, ESR, urate - Blood cultures - Joint aspiration before antibiotics (if prosthetic joint do in theatre) - Plain radiograph of joint - Radionuclide scans for septic arthritis in isolate joints e.g SI

Question 42

How is septic arthritis managed?

Answer 42

- After aspirates give **flucloxacillin IV** for 2 weeks (vancomycin if penicillin allergy) then switch to oral for 4 weeks so **6 weeks total** **_- Native joint:_** surgical irrigation and debridement/washout **_- Prosthesis:_** washout and revision surgery

Question 43

What organisms cause osteomyelitis and where do the bacteria originate from?

Answer 43

Haematogenous spread, direct innoculation (e.g open fracture or penetrating injury), direct spread from nearby infection **_Causes:_** S.Aureus, Streptococci, Enterobacteur Sp, H.Influenzae, P.Aeruginosa (IV drug users), Salmonella (sickle cell) Check for mycobacterium and fungal causes in immunosuppressed

Question 44

What is the pathophysiology of osteomyelitis?

Answer 44

When bacteria enters bone it **expresses adhesins** that bind to host tissue proteins and produce a polysaccharide extracellular matrix. From this the pathogens propagate, spread and seed If chronic infection can lead to **devascularisation of affected bone** so necrosis and resorption. Floating piece of dead bone **(sequestrum**) which is a **reservoir for infection** as abx cannot penetrate bone **Involcrum** can form where the sequestrum becomes incased in a thick sheath of periosteal new bone

Question 45

What are some risk factors for developing osteomyelitis?

Answer 45

- Diabetes mellitus - Immunosuppression (e.g AIDS, long term steroids) - Alcohol excess - IV drug use

Question 46

What are the clinical features of osteomyelitis?

Answer 46

**- Severe pain in affected region that is constant and often worse at night** **- Low grade pyrexia** - Site will be tender and may have overlying swelling and erythema - Patient may be unable to weight bear - Try to find potential sources of infection (e.g cellulitis, wounds, sinuses from drug use)

Question 47

What are some differential diagnoses for osteomyelitis?

Answer 47

- Septic arthritis - Traumatic injuries - Primary or secondary bone tumours - Potts disease (see image)

Question 48

What are some investigations to do if you suspect osteomyelitis?

Answer 48

- Routine bloods (FBC, CRP, ESR) - Blood cultures - Plain film radiographs (see image) **- Definitive diagnosis is MRI** **- Gold standard is from culture from bone biopsy** at debridement

Question 49

How is osteomyelitis managed?

Answer 49

- \>4 weeks antibiotics depending on culture (usually **Flucloxacillin** or Vancomycin if allergy) - If evidence of patient deterioration or bone destruction then **surgical management with curettage of the area**

Question 50

What are some complications of osteomyelitis?

Answer 50

- Sepsis - Soft tissue infections - If in children growth disturbance as can cause premature physeal closure - Recurrence of infection if stop abx early - Chronic osteomyelitis

Question 51

What is chronic osteomyelitis and how is it managed?

Answer 51

**- Localised ongoing bone pain** - Non-specific infection symptoms e.g malaise - May be **draining sinus tract** - Often normal inflammatory markers and blood cultures - Local bone and soft tissue debridement with long term antibiotics. Then a stage reconstruction with prolonged rehabilitation

Question 52

What are some different bone tumours?

Answer 52

- Divided into primary and secondary - Divided into benign and malignant - Most bone tumours are usually metastases

Question 53

How is metastatic bone cancer managed?

Answer 53

- Most commonly BLTKP spread to spine - Often palliatively - Can do prophylactic nailing of long bones at risk of pathological fractures (femur and humerus)

Question 54

What are some risk factors for developing a primary bone cancer and how do they present?

Answer 54

**Risks:** genetic association, previous exposure to radiation or alkylating agents in chemotherapy, benign bone conditions e.g Paget's **Presentation:** bone pain that is worse at night and not associated with movement, pathological fracture (no trauma)

Question 55

What is an osteoid osteoma and how are they managed?

Answer 55

Arise from **osteoblasts** usually in men aged 10-20 years. **Small tumours around the metaphysis of long bones** Localised progressive pain, worse at night, localised swelling/tenderness, limping **Radiolucent nidus with a rim of reactive bone** on x-ray Managed **conservatively** with imaging every 4-6 months and NSAIDs. If really painful may have surgical resection but most resolve spontaneously

Question 56

What is an osteochondroma, how does it present and how is it managed?

Answer 56

Benign bony tumours as an o**utgrowth from the metaphysis of long bones covered with a cartilaginous cap**. Usually in men aged 10-120 Often found incidentally as **asymptomatic** and slow growing but can impinge nerves as they grow **Pedunculated bony outgrowth** from meaphysis point away from joint on radiograph Same management as osteoid osteoma

Question 57

What is a chondroma, how do they present and how are they managed?

Answer 57

From chondroblasts in the medullary cavity or from the cortical surface. Usually in **20-50 year old long bones of hands, femur and humerus** **Usually asymptomatic** but can cause **pathological fracture** On x-ray **well circumscribed oval lucency with intact cortex** **If small can just observe. If large or symptomatic removal with curettage and bone grafting** as is a small risk of transforming to chondrosarcoma (malignant)

Question 58

What is a giant cell tumour, how do they present and how are they managed?

Answer 58

Osteoclastomas that come from multinucleated giant cells and stromal cells. Usually in 20-30 year olds in the epiphysis of long bones **Pain, swelling and limitation of joint movement** On x-ray eccentric lytic area **(soap bubble appearance**) **Surgical resection with potential bone graft**

Question 59

What is an osteosarcoma, how do they present and how are they managed?

Answer 59

Most common malignant bone tumour. Usually **10-14** or **\>65** years in the **metaphysis of the distal femur or proximal tibia** **Localised constant pain** and tender soft tissue mass X-ray will show **medullary and cortical bone destruction with periosteal reactions** (Codman's triangle/Sunburst pattern) **Tissue biopsy** to diagnose then **aggressive surgical resection with systemic chemotherapy** as known to metastasise to lung

Question 60

What is Ewing's sarcoma, how does it present and how is it managed?

Answer 60

Paediatric malignancies, more common in males, **affecting the diaphysis of long bones** due to **poorly differentiated neuroectodermal cells** Enlarging painful mass with tenderness and warmth X-ray shows **lytic lesion with periosteal reaction (onion appearance)** **Neoadjuvant chemotherapy and surgical resection**

Question 61

What are chondrosarcomas, how do they present and how are they managed?

Answer 61

Malignant tumours of cartilage usually aged 40-60 and affecting the axial skeleton (pelvis, shoulder, ribs) Painful and enlarging mass. X-ray shows **lytic lesions with calcification, cortical remodelling and endosteal scalloping** Intralesional curettage

Question 62

How are bone tumours investigated and how can you tell the difference between benign and malignant lesions on radiograph?

Answer 62

- Plain film radiographs - MRI to look at soft tissue involvement - CT to look at cortical involvement - Bone biopsy for definitive diagnosis

Question 63

What are some important history questions to ask in a surgical history that differ to a normal history?

Answer 63

- Any steroids or immunosuppressants? - Any anticoagulants or COCP? - Any drug allergies? - Drink or smoke? - Previous operations and anaesthesia? ALWAYS ASK ICE

Question 64

At the end of an OSCE station what are some additional investigations you should offer to do?

Answer 64

- Bedside tests (e.g urinalysis and obs) - Bloods - Imaging - Special tests (e.g aspirate) If MSK exam offer to look at joint above and below and full neurovascular exam

Question 65

What is the difference between primary and secondary bone healing?

Answer 65

**_Primary (Direct Healing - faster)_** - Stable anatomical reduction so no gap in bone (usually surgical reduction) - Healing requires only remodeling of lamellar bone, the Haversian canals and the blood vessels without callus formation. Uses cutting cone **_Secondary (Indirect Healing - more common)_** - Endochondral ossification - Haematoma, granulation tissue, soft callus, hard callus, remodelling

Question 66

How do you describe an x-ray of a fracture?

Answer 66

- State patients name, DOB and date x-ray taken - Describe view of x-ray and what we're looking at - Describe obvious deformity location (e.g metaphysis, diaphysis, epiphysis) fracture type (e.g transverse, oblique), fracture position (e.g shortened, displaces, rotated), simple vs complex

Question 67

What is the best way to check the motor function of the upper limb muscles?

Answer 67

Rock, Paper, Scissors, Ok