Visual Element: A "Top 10" badge graphic or a montage of key anatomical diagrams (Gustilo classification, hip anatomy, nerve zones).

Mastering the High-Yield: The "Must-Knows"

The FRACS Orthopaedic examination is not just about knowing the big picture; it's about the nuance, the safety margins, and the critical numbers. After reviewing thousands of exam reports, examiner feedback forms, and speaking with successful candidates, we have distilled the curriculum down to the Top 10 Clinical Pearls.

These are not just facts; they are "shibboleths"—markers that identify you to the examiners as a safe, competent, and prepared consultant-to-be.

1. The "6 Hour" Rule in Open Fractures: Myth vs. Reality

The Traditional Dogma

"All open fractures must be debrided within 6 hours."

The Evidence

This rule is historical, based on pre-antibiotic era data (Friedrich, 1898). Modern evidence suggests that time to debridement (within 12-24 hours) is not an independent predictor of infection for low-grade open fractures, provided antibiotics are started early.

Clinical Pearl: The clock that matters is the Time to Antibiotics, not the Time to Knife. Antibiotics should be administered within 3 hours (preferably 1 hour) of injury.

What Examiners Want to Hear

1. Antibiotics First: Cefazolin + Gentamicin (adding Metronidazole for farm/soil injuries).
2. Debridement Quality: "The solution to pollution is dilution." 9L of saline minimum.
3. The Exception: High-grade injuries with gross contamination (marine, sewage, farm) or vascular compromise require immediate exploration.

2. Compartment Syndrome: The "Delta P"

Diagnosing compartment syndrome is a high-stakes decision. Relying on "loss of pulses" is a trap—pulses are often preserved until the very end.

The Magic Number: Delta P (ΔP)

Absolute pressure values can be misleading due to hypotension. The critical value is the difference between the Diastolic Blood Pressure and the Compartment Pressure.

• ΔP < 30 mmHg = Indication for Fasciotomy.

Trap: Do not wait for the "5 Ps". Pain out of proportion to injury and pain on passive stretch are the only reliable early signs. Paralysis and Pulselessness are signs of missed diagnosis and amputation.

3. Hip Fracture Mortality: The "Oncological" Diagnosis

Treat a hip fracture with the urgency of a cancer diagnosis. The mortality statistics are sobering and frequently tested.

The Statistics (AOANJRR & Literature)

• 30-Day Mortality: ~8-10%
• 1-Year Mortality: ~25-30%

The "36-Hour" Window

Outcomes significantly deteriorate if surgery is delayed beyond 36-48 hours. Reasons for delay must be strictly medical (e.g., treating acute heart failure), not logistical. "Waiting for an echo" is rarely a valid reason to delay beyond 48 hours unless it will change management (e.g., to TAVI).

Evidence Corner: The HIP ATTACK trial showed that accelerated surgery (within 6 hours) didn't lower mortality in the general population but may benefit those with elevated troponins or high cardiovascular risk.

4. The AOANJRR "Hit List"

You cannot sit the Australian exam without knowing the Australian Joint Registry data.

Hip Arthroplasty

• Best Bearing: Ceramic-on-Crosslinked Polyethylene (XLPE) has the lowest revision rate.
• Worst Bearing: Metal-on-Metal (MoM) and large head (>36mm) Metal-on-Poly.
• Fixation: Hybrid TKAs (cemented tibia, uncemented femur) and Reverse Hybrid THAs (cemented stem, uncemented cup) are performing exceptionally well.

Knee Arthroplasty

• TKA vs UKA: Unicompartmental Knee Arthroplasty (UKA) has a significantly higher revision rate than Total Knee Arthroplasty (TKA), yet lower morbidity/mortality and often better functional scores (PROMs) in surviving implants.
• Patella Resurfacing: The registry generally shows lower revision rates for TKA when the patella is resurfaced (reduces revision for anterior knee pain).

5. Paediatric Remodelling Rules

When can you accept a deformity in a child?

The "Rules of Thumb"

Remodelling potential is greatest when:

1. Younger Child: (>2 years growth remaining).
2. Plane of Motion: Deformity is in the joint's axis of motion (Sagittal/Flexion-Extension). Varus/Valgus remodels less; Rotation does not remodel.
3. Near the Physis: Periosteal activity is highest here.

Clinical Pearl: A distal radius fracture with 30 degrees dorsal angulation in a 6-year-old will likely remodel perfectly. The same angulation in a 14-year-old needs reduction.

6. The "Deadly Triad" of the Knee

An ACL rupture is rarely just an ACL rupture. Failing to diagnose associated injuries is a major cause of graft failure.

1. MCL: Medial collateral ligament.
2. Lateral Meniscus Root: Often missed. Leads to rapid OA and graft overload.
3. Posterolateral Corner (PLC): The "Dark Side" of the knee.

The PLC Test

• Dial Test: Increased external rotation at 30° but normal at 90° = Isolated PLC injury.
• Increased ER at 30° AND 90° = Combined PLC + PCL injury.

Trap: Performing an ACL reconstruction in a knee with a missed PLC injury leads to rapid graft failure due to varus thrust.

7. Cauda Equina Syndrome: The Clock is Ticking

This is the number one source of litigation in spinal surgery.

Red Flags

• Bilateral sciatica / leg weakness.
• Saddle anaesthesia.
• Painless Urinary Retention: This is the most sensitive sign. Post-void residual >500ml is critical.

Timing

Decompression within 24 hours (ideally <12 hours) offers the best chance of bladder recovery. Delay >48 hours often results in permanent incontinence.

Examiner's Voice: "If you suspect it, scan it. MRI stat. If MRI is unavailable and clinical suspicion is high, transfer or explore. Do not 'wait and see'."

8. Flexor Tendon Zones: "No Man's Land"

Hand surgery anatomy is precise.

• Zone I: Distal to FDS insertion (FDP only).
• Zone II: From A1 pulley to FDS insertion. "No Man's Land." Here, FDS and FDP run tight within the sheath. Repairs here are prone to adhesions.
• Repair Strength: You need a 4-strand core suture minimum (some advocate 6) to allow for early active motion protocols, which are essential to prevent adhesions.

9. Antibiotic Prophylaxis: eTG Guidelines

For the FRACS, quote the Therapeutic Guidelines (eTG).

• Standard: Cefazolin 2g IV (3g if >120kg).
• Timing: Within 60 minutes prior to incision (to ensure tissue concentration).
• Re-dosing: Every 4 hours (2 half-lives of Cefazolin) or if blood loss >1500ml.
• Duration: Single dose is sufficient for most procedures. Maximum 24 hours. Prolonged antibiotics do not reduce infection but do increase resistance.

10. The Art of "Doing Nothing"

The mature surgeon knows when not to operate.

• Clavicle Fractures: Most mid-shaft fractures unite and function well non-operatively, despite the X-ray appearance.
• Proximal Humerus: PROFHER trial showed no difference between surgery and conservative care for many displaced fractures in the elderly.
• Achilles Rupture: Functional rehabilitation (early weight bearing in equinus) has similar re-rupture rates to surgery, without the wound risks.

Viva Tip: When presented with a complex trauma case in an elderly co-morbid patient, always start by offering a non-operative option. It shows you are treating the patient, not the X-ray.

Conclusion

These ten pearls represent the foundation of safe orthopaedic practice. They cover the critical safety checks, the evidence-based protocols, and the registry data that defines our standard of care. Master these, and you will not only pass the exam but serve your patients well.

Next Step: Go to the MCQ Bank and filter by "Clinical Pearls" to test your knowledge on these specific topics.