Most Common Orthopaedic Questions in FRCEM

Topic priority at a glance

Orthopaedics is a high-yield area in MRCEM and FRCEM because it tests core emergency medicine judgement rather than operative detail. Examiners want safe ED practice: recognising limb-threatening problems, choosing the right imaging, giving timely analgesia, documenting neurovascular findings properly, reducing when appropriate, and referring or discharging safely. The commonest marks come from injuries and complications seen every day in UK emergency departments: open fractures, compartment syndrome, septic arthritis, hip fracture, shoulder dislocation, distal radius fracture, scaphoid injury, ankle trauma, knee dislocation, and occult fractures with normal initial X-rays.

The recurring exam theme is simple: treat the patient, not the film. A normal X-ray does not exclude important injury. Palpable pulses do not exclude compartment syndrome or arterial injury. “Neurovascularly intact” is not enough documentation. If a wound lies near a fracture, think open fracture until proven otherwise. If a joint is hot, swollen and painful, think septic arthritis until excluded. These are the decisions that separate safe candidates from unsafe ones.

Why These Orthopaedic Questions Matter in FRCEM

Musculoskeletal presentations make up a large proportion of ED workload. Most are minor, but a small number are time-critical and limb-threatening. Orthopaedic questions are therefore common in both written and clinical exams because they reflect real emergency practice.

In exam terms, orthopaedics tests whether you can:

• identify red flags early
• prioritise immediate ED actions over definitive orthopaedic management
• choose appropriate imaging and know when plain films are not enough
• perform and document a focused neurovascular examination
• recognise injuries needing urgent reduction, antibiotics, admission or theatre referral
• discharge stable injuries safely with appropriate follow-up and safety-netting

Commonly tested themes include:

• open fracture management
• compartment syndrome
• septic arthritis
• hip fracture and occult hip fracture
• shoulder dislocation, especially missed posterior dislocation
• distal radius fracture reduction and analgesia
• scaphoid injury with normal X-rays
• Ottawa ankle and knee rules
• Lisfranc injury and tibial plateau fracture
• knee dislocation with vascular risk
• paediatric supracondylar fracture and pulled elbow

Key Definitions

Open fracture
A fracture with communication between the fracture and the external environment. Any wound near a fracture should be treated as an open fracture until proven otherwise.

Compartment syndrome
Raised pressure within a closed fascial compartment causing impaired tissue perfusion and risk of muscle and nerve necrosis. It is a clinical diagnosis and a surgical emergency.

Septic arthritis
Infection within a joint space causing rapid cartilage destruction and systemic illness. It requires urgent specialist involvement and usually admission.

Occult fracture
A clinically important fracture not visible on initial plain radiographs.

Neurovascular compromise
Impaired distal perfusion or nerve function associated with a fracture or dislocation. This may require urgent reduction or specialist intervention.

Reduction
Manipulation of a fracture or dislocation to restore alignment. In ED questions, the issue is usually whether reduction is needed urgently and how to do it safely.

Essential Pathophysiology

Most orthopaedic emergencies are dangerous because of one of four mechanisms:

• loss of perfusion, as in arterial injury or compartment syndrome
• progressive soft tissue damage, as in dislocation or unstable fracture
• infection, as in open fracture or septic arthritis
• occult structural instability, where normal initial imaging falsely reassures

Compartment syndrome develops when tissue pressure rises above capillary perfusion pressure. Muscle and nerve ischaemia follow. Pain out of proportion and pain on passive stretch are early signs. Pulselessness is late and unreliable.

Open fractures carry a high risk of contamination, infection and soft tissue injury. Early antibiotics, splintage and specialist referral matter more in the ED than fracture classification.

Septic arthritis rapidly destroys cartilage and may present without dramatic systemic signs, especially in older adults and immunosuppressed patients.

Dislocations can stretch or compress nerves and vessels. Delay in reduction increases pain, swelling and risk of complications. Hip dislocation is particularly time-critical because of the risk of avascular necrosis.

Occult fractures are common where anatomy is complex or overlap obscures injury. Typical examples are scaphoid fracture, occult hip fracture, posterior shoulder dislocation, Lisfranc injury and tibial plateau fracture.

Clinical Presentation

Orthopaedic presentations in the ED usually fall into a few recognisable patterns.

• Pain, swelling and deformity after trauma: think fracture or dislocation
• Pain out of proportion, tense limb, pain on passive stretch: think compartment syndrome
• Hot swollen painful joint with reduced range of movement: think septic arthritis
• Inability to weight bear after a fall, especially in an older adult: think hip fracture even if X-rays are normal
• Wound near a fracture: think open fracture
• Normal AP shoulder film but fixed internal rotation and limited external rotation: think posterior shoulder dislocation
• Midfoot pain after twisting or crush injury with plantar bruising: think Lisfranc injury
• Snuffbox tenderness after a fall onto an outstretched hand: think scaphoid injury even if X-rays are normal

Always ask about mechanism, timing, ability to weight bear or use the limb, anticoagulants, tetanus status where relevant, and baseline mobility or function.

Red Flags and High-Risk Features

The highest-yield orthopaedic red flags are:

• open fracture
• compartment syndrome
• septic arthritis
• dislocation with neurovascular compromise
• knee dislocation or suspected spontaneously reduced knee dislocation
• pelvic fracture with haemodynamic instability
• hip dislocation
• suspected occult hip fracture in a non-weight-bearing patient
• cauda equina or spinal cord symptoms in trauma overlap cases

Specific red flag clues:

Differential Diagnosis

Common differentials that appear in exams include:

• fracture versus dislocation versus severe soft tissue injury
• septic arthritis versus crystal arthropathy versus reactive arthritis
• scaphoid fracture versus wrist sprain
• ankle fracture versus ligamentous injury
• Lisfranc injury versus simple midfoot sprain
• occult hip fracture versus soft tissue hip injury
• compartment syndrome versus severe bruising or post-injury pain
• posterior shoulder dislocation versus frozen shoulder or rotator cuff injury
• tibial plateau fracture versus ligamentous knee injury

In exam stems, the discriminator is usually not the full differential list but the clue that makes one diagnosis unsafe to miss.

Initial ED Assessment

Start with ABCDE in major trauma or any unstable patient. Orthopaedic injuries can distract from life-threatening problems.

For isolated limb injury, a safe ED sequence is:

1. Analgesia early
2. Immobilise or splint
3. Assess skin and look for open fracture
4. Perform and document neurovascular examination
5. Image appropriately
6. Reduce urgently if indicated
7. Repeat and document neurovascular examination after intervention
8. Decide on referral, admission or discharge

Neurovascular assessment must be specific. Document:

• distal pulses and perfusion
• colour, warmth and capillary refill where relevant
• motor function by named nerve
• sensation by named nerve territory
• pain limiting examination if applicable
• findings before and after reduction, splintage or cast application

Examples of high-yield nerve checks:

Do not write only “NVI”. That is poor exam technique and poor documentation.

Investigations

Plain radiographs are first-line for most injuries, but the exam repeatedly tests when plain films are not enough.

Plain radiographs

Request the correct views and include the joint above and below where relevant. Common traps are inadequate views and failure to request additional views for suspected dislocation.

Examples:

• shoulder trauma: AP plus axillary or scapular Y view if dislocation is possible
• wrist trauma: standard wrist series; consider scaphoid views depending on local pathway
• ankle trauma: standard ankle views if Ottawa criteria met
• knee trauma: standard knee views if Ottawa criteria met

Ottawa rules

These are common exam questions. They reduce unnecessary imaging but apply only in appropriate clinical settings and do not replace judgement.

Ottawa ankle rules: ankle X-ray if pain in malleolar zone and any of:

• bony tenderness at posterior edge or tip of lateral malleolus
• bony tenderness at posterior edge or tip of medial malleolus
• inability to bear weight both immediately and in ED for four steps

Foot X-ray if pain in midfoot zone and any of:

• bony tenderness at base of fifth metatarsal
• bony tenderness at navicular
• inability to bear weight both immediately and in ED for four steps

Ottawa knee rule: knee X-ray if acute knee injury and any of:

• age 55 or over
• isolated patellar tenderness
• tenderness at fibular head
• inability to flex knee to 90 degrees
• inability to bear weight for four steps both immediately and in ED

Use caution if assessment is unreliable because of intoxication, communication difficulty, distracting injury or altered mental state.

When X-rays are normal but suspicion remains high

Blood tests

Blood tests are not routine for simple fractures. They are relevant in:

• suspected septic arthritis: FBC, CRP, U&Es, blood cultures if febrile or septic
• major trauma or pelvic injury: trauma bloods, group and save or crossmatch as indicated
• older adults with hip fracture: routine admission bloods and ECG according to pathway

Joint aspiration

Joint aspiration may be required in suspected septic arthritis, usually after discussion with the relevant team and by a clinician competent to perform it. Send aspirate for microscopy, culture and crystal analysis. If the patient is septic or unstable, do not delay antibiotics for aspiration.

Management in the Emergency Department

The exam usually asks for the immediate ED step, not definitive orthopaedic management. A safe answer starts with analgesia, immobilisation, neurovascular assessment and recognition of emergencies.

General ED management sequence

1. ABCDE if major trauma or unstable
2. Give prompt analgesia
3. Immobilise the limb or joint
4. Assess for open fracture and skin compromise
5. Document neurovascular status
6. Image appropriately
7. Reduce urgently if indicated and safe
8. Repeat neurovascular examination and obtain post-reduction imaging where appropriate
9. Refer, admit or discharge with clear follow-up and safety-netting

Analgesia and regional anaesthesia

Analgesia should be proportionate and early. Severe traumatic pain usually needs prompt strong analgesia, often titrated IV opioid, plus splintage and simple analgesics where appropriate. In children or where IV access is delayed, intranasal opioid may be appropriate according to local practice.

Do not delay analgesia until after imaging.

Hip fracture: NICE supports offering a nerve block such as fascia iliaca block for suspected hip fracture, delivered by trained staff under local governance. This is a classic UK exam point. Key safety points are:

• confirm the correct side
• use local procedural safety checks
• calculate local anaesthetic dose carefully
• aspirate and inject incrementally according to technique
• monitor the patient appropriately
• be prepared to recognise and treat local anaesthetic systemic toxicity
• use it as part of a broader analgesic plan, not as the only intervention

Distal radius reduction: for exam purposes, Bier’s block remains a traditional UK answer for suitable closed distal radius reduction where trained staff, monitoring and governance arrangements exist. Real-world practice varies and may include haematoma block or procedural sedation. The best answer depends on the stem.

Common analgesia traps:

• undertreating severe pain
• discussing reduction before analgesia
• choosing a block or sedation technique without mentioning monitoring, training or local policy
• using nitrous oxide alone for a clearly painful displaced fracture reduction

Reduction principles

Urgent reduction is usually indicated for:

• dislocation with neurovascular compromise
• skin tenting or threatened skin
• severe deformity causing pain or soft tissue risk
• hip dislocation
• some ankle fracture-dislocations and grossly displaced injuries after discussion and according to local practice

Before reduction:

• obtain appropriate analgesia or anaesthesia
• document neurovascular status
• check imaging unless immediate reduction is required for limb threat
• involve a senior early if the injury is complex, open, unstable or unfamiliar

After reduction:

• reassess and document neurovascular status
• re-image where appropriate
• immobilise
• arrange follow-up or admission

Do not repeatedly attempt difficult reductions. Escalate early.

Open fractures

This is one of the highest-yield UK orthopaedic topics. Follow BOAST principles and local policy.

Immediate ED priorities:

• recognise it: any wound near a fracture is an open fracture until proven otherwise
• give IV antibiotics as soon as possible
• assess tetanus status and manage according to national guidance
• cover the wound with a sterile saline-soaked dressing or clean sterile dressing according to local policy
• splint the limb
• avoid repeated wound exploration in ED
• remove gross contamination only if appropriate and according to local practice
• photograph the wound if local policy supports this and it aids specialist planning
• urgent orthopaedic or orthoplastic discussion

Common exam trap: sending the patient for routine fracture clinic after dressing and oral antibiotics. That is unsafe.

Compartment syndrome

Compartment syndrome is a clinical diagnosis. Do not wait for absent pulses.

Key features:

• pain out of proportion
• pain on passive stretch
• tense swollen compartment
• paraesthesia or altered sensation
• increasing analgesia requirement

Late signs include weakness, pallor and pulselessness.

Immediate ED actions:

• remove constrictive dressings, casts or bandages
• keep the limb at heart level, not elevated high above it
• give analgesia
• urgent senior and orthopaedic review
• prepare for fasciotomy pathway if confirmed or strongly suspected

Common exam trap: reassuring yourself because pulses are present.

Septic arthritis

Think of septic arthritis in any acutely painful swollen joint with reduced range of movement, especially if the patient is febrile, immunosuppressed, has a prosthetic joint, or cannot weight bear.

ED priorities:

• urgent senior and orthopaedic involvement
• blood tests including inflammatory markers
• blood cultures if febrile or septic
• joint aspiration where appropriate and feasible
• start antibiotics after cultures and aspiration if the patient is stable
• if septic or unstable, do not delay antibiotics
• admit

Crystal arthritis does not exclude sepsis. A patient can have both.

Hip fracture and occult hip fracture

Older adults with hip pain after a fall should be assumed to have a hip fracture until excluded. Give analgesia early and consider fascia iliaca block if trained and appropriate.

If X-rays are negative but the patient still has significant pain or cannot weight bear, think occult hip fracture. MRI is preferred. CT is used if MRI is unavailable or contraindicated.

Do not discharge a non-weight-bearing older patient with “soft tissue injury” after normal hip X-rays if clinical suspicion remains high.

Shoulder dislocation

Anterior shoulder dislocation is common. Check and document axillary nerve function before and after reduction. Obtain appropriate imaging unless immediate reduction is required because of neurovascular compromise. After successful reduction, re-image and reassess neurovascular status.

Posterior shoulder dislocation is commonly missed. Think of it after seizure, electrocution or trauma with the arm held adducted and internally rotated. The patient cannot externally rotate. AP films may look deceptively normal. Ask for axillary or scapular Y views.

Common exam trap: diagnosing “shoulder sprain” after a seizure with a normal AP film.

Elbow dislocation

Assess brachial artery and median, ulnar and radial nerve function. Simple elbow dislocations often need urgent reduction, then reassessment and imaging. Look for associated fractures. Irreducible dislocation, fracture-dislocation or neurovascular compromise needs urgent specialist involvement.

Distal radius fracture

Common exam themes are reduction, analgesia choice, median nerve assessment and post-reduction care. A displaced distal radius fracture may need manipulation in ED depending on local pathway and fracture pattern. Document median nerve function before and after reduction. Immobilise and arrange fracture clinic follow-up if appropriate.

Scaphoid injury

With snuffbox tenderness or scaphoid tubercle tenderness after a fall onto an outstretched hand, normal X-rays do not exclude fracture. Immobilise according to local pathway and arrange early follow-up or imaging. MRI is increasingly preferred where available.

Common exam trap: discharging with no immobilisation and no follow-up because the X-ray is normal.

Ankle fractures and Ottawa ankle rules

Use Ottawa rules appropriately. Distinguish stable injuries suitable for discharge from unstable fractures or fracture-dislocations needing reduction, admission or urgent review. Always assess skin, syndesmotic tenderness, medial clear space concerns, and neurovascular status.

Base of fifth metatarsal and Lisfranc injury

Base of fifth metatarsal fractures are common and often straightforward, but Lisfranc injury is the high-yield miss. Think of Lisfranc injury with midfoot pain, swelling, plantar bruising and difficulty weight bearing. Normal non-weight-bearing films do not exclude it. CT is often helpful.

Tibial plateau fracture

Suspect this in knee trauma with inability to weight bear, large effusion or lateral joint line tenderness, especially after axial load or valgus stress. Plain films may be subtle. CT often clarifies the diagnosis. These injuries may be unstable and should not be dismissed as simple ligament injury.

Knee dislocation

This is a classic exam emergency because of popliteal artery injury. The knee may have reduced spontaneously before arrival.

Key points:

• assess distal pulses and perfusion carefully
• check common peroneal nerve function
• normal pulses do not fully exclude arterial injury
• follow local pathway for vascular assessment, which may include ABI, Doppler or CT angiography
• urgent senior and orthopaedic involvement
• admission or observation is often required

Pelvic fracture

In major trauma with suspected pelvic injury and haemodynamic instability, follow trauma protocols. Apply a pelvic binder if indicated and involve trauma, orthopaedic and interventional teams early according to local major trauma pathway.

Disposition, Referral and Follow-Up

Disposition depends on stability, complication risk and need for intervention.

Safe discharge requires:

• adequate analgesia
• appropriate immobilisation
• documented neurovascular status
• clear written advice
• safety-netting for increasing pain, numbness, colour change, swelling, fever or inability to cope
• a clear follow-up plan, often fracture clinic or virtual fracture clinic

In exams, if there is uncertainty about stability, vascular status, infection or occult injury, escalation is usually safer than discharge.

Special Groups

Paediatrics

Paediatric orthopaedics is common in MRCEM and FRCEM.

Supracondylar fracture: high-yield because of neurovascular risk. Check radial pulse, hand perfusion, median nerve and anterior interosseous nerve function. Significant displacement or neurovascular compromise needs urgent orthopaedic involvement.

Pulled elbow: classic younger child with arm held pronated and slightly flexed after traction injury. Usually no swelling or bruising. If history and examination are typical, reduction can be attempted without imaging. If atypical, swollen, bruised or not using the arm after reduction, image and reconsider the diagnosis.

Growth plate injuries: be cautious with apparently minor injuries around physes. If clinical suspicion is high, immobilise and arrange follow-up even if X-rays are normal.

Non-accidental injury: always consider safeguarding where history is inconsistent, injuries are unusual for developmental stage, or there are multiple injuries.

Older adults

Older adults are at high risk of hip fracture, occult fracture, delirium, pressure injury and analgesic complications. Do not undertreat pain. Consider regional anaesthesia where appropriate. Be cautious with NSAIDs and opioids in frailty, renal impairment and cognitive impairment.

Pregnancy

Do not withhold necessary imaging if clinically indicated. Use shielding and dose minimisation according to local radiology policy. Analgesia and immobilisation remain important. Major trauma pathways still apply.

Immunosuppressed patients

Have a lower threshold for septic arthritis, osteomyelitis and severe soft tissue infection. Systemic features may be muted.

Common Pitfalls

• missing an open fracture because the wound looks small
• writing “NVI” without detail
• forgetting to repeat neurovascular examination after reduction or splintage
• assuming palpable pulses exclude compartment syndrome
• accepting a normal X-ray despite strong clinical suspicion
• missing posterior shoulder dislocation
• discharging a patient who cannot weight bear after normal hip X-rays
• failing to consider septic arthritis in a hot swollen joint
• delaying antibiotics in open fracture
• attempting repeated difficult reductions without senior help
• using Ottawa rules outside an appropriate clinical context
• failing to examine the joint above and below
• forgetting tetanus assessment in open injuries

FRCEM and MRCEM Exam Tips

Most orthopaedic questions can be answered safely by asking three things:

1. Is this limb-threatening or time-critical?
2. What is the immediate ED action?
3. What must I document and reassess?

High-yield exam habits:

• say “analgesia, immobilisation, neurovascular assessment” early
• if there is a wound near a fracture, say “treat as open fracture”
• if there is severe escalating pain, say “consider compartment syndrome”
• if there is a hot swollen joint, say “septic arthritis until excluded”
• if reduction is mentioned, say “document neurovascular status before and after”
• if X-rays are normal but suspicion remains high, choose further imaging rather than discharge
• use UK pathways and guidance, not generic textbook answers

Traditional exam favourites include:

• fascia iliaca block for suspected hip fracture
• Bier’s block as a classic answer for suitable distal radius reduction cases where governance allows
• MRI for occult hip fracture
• axillary nerve in anterior shoulder dislocation
• radial nerve in humeral shaft fracture
• common peroneal nerve and popliteal artery risk in knee dislocation
• anterior interosseous nerve in supracondylar fracture

How This Appears in SBA Questions

Typical stem 1: “A patient has severe pain in the lower leg after tibial fracture. Pulses are present. What is the most important next step?”
Key clue: pain out of proportion, pulses present does not reassure.
Best answer: suspect compartment syndrome, remove constriction, urgent orthopaedic review.

Typical stem 2: “An elderly patient cannot weight bear after a fall. Hip X-rays are normal.”
Key clue: persistent inability to weight bear despite normal films.
Best answer: MRI for occult hip fracture, or CT if MRI unavailable/contraindicated.

Typical stem 3: “A wound lies over a forearm fracture.”
Key clue: any wound near fracture.
Best answer: treat as open fracture, IV antibiotics, tetanus assessment, sterile dressing, splintage, urgent orthopaedic referral.

Typical stem 4: “A patient after a seizure has shoulder pain and cannot externally rotate the arm. AP film appears normal.”
Key clue: seizure plus inability to externally rotate.
Best answer: suspect posterior shoulder dislocation and obtain axillary or scapular Y view.

Typical stem 5: “After reducing a shoulder dislocation, what should be done next?”
Key clue: post-reduction care.
Best answer: repeat and document neurovascular examination, then post-reduction imaging and immobilisation.

Typical stem 6: “A child has a displaced supracondylar fracture.”
Key clue: paediatric elbow injury with neurovascular risk.
Best answer: urgent orthopaedic involvement and careful neurovascular assessment, especially median/AIN and perfusion.

Common wrong-answer traps:

• choosing definitive surgery rather than the immediate ED step
• choosing discharge when urgent referral is needed
• choosing repeat plain X-ray when MRI or CT is the better next test
• focusing on fracture classification instead of red flags
• forgetting analgesia and splintage
• forgetting tetanus and antibiotics in open fracture

Key Takeaways

• Orthopaedic exam marks come from safe ED decision-making, not operative detail.
• Always look first for open fracture, compartment syndrome, septic arthritis, neurovascular compromise and occult injury.
• Give analgesia early and immobilise before chasing perfect imaging.
• Document neurovascular findings specifically and repeat them after any intervention.
• Any wound near a fracture should be treated as an open fracture until proven otherwise.
• Compartment syndrome is a clinical diagnosis; pulses may still be present.
• A normal X-ray does not exclude scaphoid fracture, occult hip fracture, posterior shoulder dislocation, Lisfranc injury or tibial plateau fracture.
• MRI is preferred for occult hip fracture when X-rays are negative and suspicion remains high.
• Posterior shoulder dislocation is a classic miss after seizure or electrocution.
• Knee dislocation carries a risk of popliteal artery injury even if distal pulses are present.
• Septic arthritis needs urgent specialist involvement and usually admission.
• In SBA questions, answer the immediate ED step, not the final orthopaedic plan.

Further Reading

• NICE guideline: Hip fracture: management
• NICE guideline: Fractures (non-complex): assessment and management
• NICE guideline: Fractures (complex): assessment and management
• BOAST guidance from the British Orthopaedic Association, especially open fractures and acute management standards
• RCEM Learning resources on musculoskeletal injuries, procedural sedation and regional anaesthesia
• Resuscitation Council UK guidance relevant to peri-arrest trauma care and local anaesthetic toxicity pathways used locally
• SIGN guidance where locally relevant for musculoskeletal and trauma pathways

Related on EM Final Exams

• Top 20 Most Examined Topics in FRCEM
• Top Trauma Topics You Must Know for FRCEM
• Most Common ECGs in FRCEM Exams
• Top 15 Paediatric Emergencies for MRCEM

Authoritative Sources

• NICE guidance
• Royal College of Emergency Medicine (RCEM)

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