Fellowship of the Royal College of Surgeons (FRCS) Trauma and Orthopaedic Surgery Flashcards

24 sample cards from the Trauma and Orthopaedic Surgery deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. Distinguish complete from incomplete spinal cord injury and the role of spinal shock.

   Complete injury: no motor or sensory function below the level, including no sacral sparing (S4-5). Incomplete: some preserved function below the level (e.g., sacral sparing - perianal sensation, voluntary anal contraction). The completeness can only be confirmed after spinal shock resolves, marked by return of the bulbocavernosus reflex.

2. Describe central cord syndrome: mechanism, deficit pattern, and prognosis.

   Most common incomplete cord syndrome, typically from a hyperextension injury in an older patient with pre-existing cervical spondylosis. Causes greater weakness in the upper limbs than the lower limbs (centrally located cervical motor tracts), with variable sensory loss and bladder dysfunction. Prognosis for recovery is generally good but often incomplete.

3. Contrast anterior cord syndrome and Brown-Sequard syndrome.

   Anterior cord syndrome: anterior spinal artery territory; loss of motor and pain/temperature below the lesion with preserved proprioception/vibration (dorsal columns spared); poor prognosis. Brown-Sequard (cord hemisection): ipsilateral loss of motor and proprioception/vibration, contralateral loss of pain/temperature; best prognosis of the incomplete syndromes.

4. What organism most commonly causes pyogenic vertebral osteomyelitis, and what investigation is most sensitive?

   Staphylococcus aureus is the most common organism. MRI with contrast is the most sensitive and specific imaging investigation (showing disc and endplate enhancement, paravertebral/epidural collections). Blood cultures and image-guided biopsy identify the organism to guide targeted antibiotic therapy.

5. Which primary cancers most commonly metastasise to the spine, and which are typically lytic vs sclerotic?

   Breast, prostate, lung, kidney (renal), and thyroid. Predominantly lytic: lung, kidney, thyroid. Sclerotic (blastic): prostate (and breast can be mixed). Mnemonic 'BLT with Kosher Pickle': Breast, Lung, Thyroid, Kidney, Prostate. The spine is the most common site of skeletal metastasis.

6. How is a scoliosis curve measured and what magnitude generally triggers surgical consideration in adolescent idiopathic scoliosis?

   By the Cobb angle, measured between lines drawn along the end-plates of the most tilted upper and lower vertebrae of the curve. A curve $>10^{\circ}$ defines scoliosis; bracing is considered for curves ~$25\text{-}40^{\circ}$ in skeletally immature patients, and surgery (fusion) is generally considered for curves $>45\text{-}50^{\circ}$.

7. What is Risser sign and why is it important in scoliosis management?

   The Risser sign grades skeletal maturity by the ossification of the iliac apophysis from lateral to medial, graded 0 (no ossification) to 5 (complete fusion to iliac crest). Lower grades indicate greater remaining growth and higher risk of curve progression, guiding the timing of bracing versus surgery.

8. What is developmental dysplasia of the hip (DDH) and which clinical tests screen for it in neonates?

   Abnormal development of the hip with instability/subluxation/dislocation and a shallow acetabulum. Screened with the Ortolani test (reduces a dislocated hip - 'O' for out-to-in/relocate with a clunk) and the Barlow test (dislocates a reducible hip). Ultrasound is the imaging modality of choice under ~4-6 months.

9. What is slipped capital femoral epiphysis (SCFE), its typical patient, and management principle?

   Displacement of the femoral epiphysis (head) posteriorly and inferiorly relative to the metaphysis through the physis, typically in an overweight adolescent (10-16 years), presenting with hip/knee pain and obligatory external rotation on flexion. Treatment is urgent in-situ pinning to prevent progression and avascular necrosis; the slip is unstable if weight-bearing is not possible.

10. Describe the typical course of Legg-Calve-Perthes disease and a key prognostic factor.

    Idiopathic avascular necrosis of the femoral head in children (typically 4-8 years), progressing through necrosis, fragmentation, reossification, and remodelling. Key prognostic factors: age at onset (younger = better), and degree of femoral head involvement/congruency (lateral pillar/Herring classification). Aim is to keep the femoral head contained and spherical.

11. What is carpal tunnel syndrome, the nerve and motor sign involved, and provocative tests?

    Compression of the median nerve at the wrist beneath the flexor retinaculum. Causes paraesthesia in the radial 3.5 digits and thenar wasting (abductor pollicis brevis weakness). Provocative tests: Tinel's sign (tapping over the nerve) and Phalen's test (sustained wrist flexion). Nerve conduction studies confirm the diagnosis.

12. What is Dupuytren's contracture and which structures/joints are typically involved?

    A progressive fibroproliferative disorder of the palmar fascia with myofibroblast proliferation forming nodules and cords, causing flexion contracture, most commonly of the ring and little fingers at the MCP and PIP joints. Associated with northern European descent, alcohol, diabetes, and a positive family history (Garrod's pads, Ledderhose, Peyronie's).

13. Why is a scaphoid fracture prone to avascular necrosis and non-union?

    The scaphoid receives its blood supply predominantly retrograde from branches of the radial artery entering distally (dorsal ridge). Therefore proximal pole fractures interrupt the blood supply to the proximal fragment, leading to a high risk of avascular necrosis and non-union, especially with delayed treatment.

14. How does the Enneking (surgical staging) system classify musculoskeletal tumours?

    Benign lesions are staged 1 (latent), 2 (active), 3 (aggressive). Malignant lesions are staged by grade (low = I, high = II) and compartment status (A = intracompartmental, B = extracompartmental), with stage III denoting metastatic disease. It guides the required surgical margin (intralesional, marginal, wide, radical).

15. List the surgical margins for tumour resection and where each plane lies.

    Intralesional (through the tumour - debulking), Marginal (through the reactive zone/pseudocapsule - risk of residual satellite cells), Wide (through normal tissue beyond the reactive zone, leaving a cuff of normal tissue), and Radical (removal of the entire compartment containing the tumour). Malignant tumours require at least a wide margin.

16. Name the most common primary bone sarcomas and their typical age and location.

    Osteosarcoma: adolescents/young adults, metaphysis of long bones (distal femur, proximal tibia), 'sunburst' periosteal reaction and Codman's triangle. Ewing's sarcoma: children/adolescents, diaphysis, 'onion-skin' periosteal reaction, t(11;22) translocation. Chondrosarcoma: older adults, axial skeleton/pelvis, cartilage-forming.

17. What red-flag features in a soft tissue lump suggest sarcoma and mandate referral?

    A lump that is larger than 5 cm, deep to fascia, rapidly growing, painful, or recurrent after previous excision. Any such lump warrants urgent referral to a specialist sarcoma centre for MRI and biopsy (planned through the future resection field) before any excision - avoid 'whoops' unplanned excisions.

18. Define osteomyelitis and contrast the typical routes/patterns in children vs adults.

    Infection of bone and marrow. In children it is usually haematogenous, affecting the metaphysis of long bones (slow blood flow in sinusoidal loops). In adults it is more often contiguous (open fracture, surgery, diabetic foot) or secondary to vascular insufficiency. Staph aureus is the most common organism overall.

19. What is the gold-standard treatment principle for chronic osteomyelitis, and what is an involucrum vs sequestrum?

    Thorough surgical debridement of all dead/infected tissue (excision of sequestrum), dead-space management, stable skeleton, soft tissue coverage, plus targeted antibiotics. A sequestrum is a fragment of dead, avascular bone; an involucrum is the new periosteal bone formed around it. Antibiotics alone cannot eradicate infection harboured in avascular sequestra.

20. How is native (non-prosthetic) septic arthritis diagnosed and managed, and which classic criteria aid the knee?

    Diagnosis by urgent joint aspiration: turbid fluid, raised WCC (commonly >50,000/mm3 with neutrophil predominance), Gram stain and culture. Kocher criteria (paediatric hip) use non-weight-bearing, fever >38.5C, ESR >40, WCC >12,000. Management: urgent surgical washout/arthroscopic lavage and IV antibiotics to prevent rapid cartilage destruction.

21. Describe the Seddon classification of peripheral nerve injury.

    Neurapraxia: local conduction block, axon intact, full recovery (myelin injury). Axonotmesis: axon disrupted with Wallerian degeneration but endoneurial tubes/connective tissue intact, recovery by regeneration at ~1 mm/day. Neurotmesis: complete transection of the nerve including connective tissue, no spontaneous recovery, requires surgical repair.

22. What is the rate of peripheral nerve regeneration, and what principle guides timing of nerve repair?

    Axonal regeneration proceeds at approximately 1 mm/day (about 1 inch/month). Sharp, clean transections are best repaired primarily (within 72 hours). Tidy/blunt injuries are repaired early; contaminated or crush injuries are tagged and repaired at ~3 weeks once the zone of injury declares itself, before motor end-plates degenerate (~12-18 months).

23. What is a Tscherne classification used for, and why does it matter in closed fractures?

    The Tscherne classification grades the severity of the soft tissue injury in closed fractures (C0 minimal to C3 severe with compartment syndrome/vascular injury). It matters because the soft tissue envelope, not just the bony injury, dictates timing of surgery - severe swelling/blistering may mandate delay or temporary spanning external fixation before definitive fixation.

24. State Wolff's law and Hueter-Volkmann law and their orthopaedic relevance.

    Wolff's law: bone remodels and adapts its architecture in response to the mechanical loads placed upon it (load increases density along stress lines; disuse causes resorption). Hueter-Volkmann law: increased compression across a physis inhibits growth and reduced/tension stimulates it - explaining progression of angular deformity and the rationale for guided growth (hemiepiphysiodesis).

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