ABOS Part I Survival Guide: The Comprehensive Blueprint

The American Board of Orthopaedic Surgery (ABOS) Part I Examination is arguably the most significant academic hurdle in an orthopaedic surgeon's training. It is the culmination of five years of residency, condensed into a single day of computer-based multiple-choice questions.

Passing this exam allows you to proceed to your fellowship and eventually Part II (Oral Boards). Failing it puts your career on hold, creates stigma, and forces a grueling retake year.

This guide is not just a list of tips; it is a strategic blueprint designed to maximize your efficiency and score.

The Enemy: Understanding the Exam

Structure

• Format: ~300-320 multiple-choice questions.
• Timing: Administered in a single day, usually in July. Divided into blocks with break time.
• Scoring: Scaled score. The pass rate historically hovers around 95-97% for first-time takers, but don't let that statistic lull you into complacency. The failing 3-5% are often residents who were clinically excellent but academically disorganized.

The Blueprint (Content Weighting)

The ABOS publishes a blueprint. Ignore it at your peril. The approximate breakdown is:

• Basic Science: 20-25% (The silent killer)
• Adult Reconstruction: 15%
• Trauma: 15%
• Pediatrics: 10-12%
• Spine: 10-12%
• Hand: 10%
• Foot & Ankle: 10%
• Sports: 10%
• Tumor: 5% (But extremely high yield per topic)

Trap: Many residents spend weeks studying complex revision hip arthroplasty (which they love) and ignore basic science (which they hate). Basic Science is 20-25% of the exam. You cannot pass if you bomb it.

The Timeline: A Strategic Approach

You cannot cram for this exam in two weeks. It requires a slow burn followed by a sprint.

Phase 1: The Foundation (PGY 1-4)

• OITE Matters: The Orthopaedic In-Training Examination (OITE) is the best predictor of ABOS performance. Take it seriously every year.
• ResStudy: Use AAOS ResStudy throughout the year.
• Read: Don't just do questions; read comprehensive texts (Miller, Orthobullets) to build a scaffold of knowledge.

Phase 2: The Ramp Up (January - March of PGY-5)

• Assessment: Take a full-length mock exam to identify your weak areas.
• Schedule: Create a dedicated study calendar. Block out time.
• Resource consolidation: Pick your primary resources. Do not use 10 different books. Pick 2-3 and master them.

Phase 3: The Sprint (April - July)

This is "Board Study Mode."

• Volume: 50-100 questions per day.
• Review: Read the explanations for every question, even the ones you got right.
• Weakness Targeting: If you suck at Foot & Ankle, study it first. Do not leave your weakest subject for the week before the exam.

Resource Deep Dive

1. AAOS ResStudy / Orthopaedic Knowledge Update (OKU)

• The Gold Standard. The questions often feel very similar to the actual exam.
• Pros: Official source. High reliability.
• Cons: Interface can be clunky. Explanations sometimes lack depth.

2. Orthobullets

• The Modern Standard.
• Pros: Incredible volume of questions. Adaptive learning algorithms. Comments section often contains gold nuggets.
• Cons: Can be fragmented. Some questions are too "in the weeds" or controversial.

3. Miller's Review of Orthopaedics

• The Bible.
• Pros: If it's in Miller, it's on the test. Dense, high-yield facts.
• Cons: Unreadable as a narrative. It is a reference/bullet-point book. Use it to look up concepts, not for bedtime reading.

4. OrthoVellum (Our Platform)

• The Visual Integrator.
• Pros: Modern visuals, concept-based learning, integrated basic science.
• Cons: Newer player in the field.

High-Yield Content Domains

Basic Science (The 25%)

• Materials: Stress/strain curves, corrosion, wear mechanisms, modulus of elasticity.
• Biology: Bone healing (primary vs secondary), BMPs, PTH, Vitamin D metabolism, cell biology (osteoclast origin).
• Stats: Sensitivity/Specificity, PPV/NPV, Levels of Evidence, T-test vs Chi-square.
• Infection: Antibiotic mechanisms of action, bacterial biofilms.

Tumor (Pattern Recognition)

• You must memorize the Radiographic Appearance, Age Group, Location, and Histology of every primary bone tumor.
• Example: 15-year-old, distal femur, sunburst periosteal reaction = Osteosarcoma.
• Example: Epiphysis, chicken-wire calcification = Chondroblastoma.

Pediatrics

• Limping Child Algorithm: Age 0-3 (Septic hip vs fracture), 4-10 (Perthes), 11-16 (SCFE).
• Genetics: Achondroplasia (FGFR3), Marfan's (Fibrillin), Osteogenesis Imperfecta (Type 1 collagen).

Trauma

• Pelvis: Young-Burgess and Tile classifications. Hemodynamic management.
• Spine Trauma: TLICS score, incomplete cord syndromes (Central vs Brown-Sequard vs Anterior).
• Compartment Syndrome: Delta pressure < 30 mmHg. Know the compartments of the leg and forearm cold.

Test Day Strategy

1. Stamina is Key: It is a marathon. Build up your endurance by doing 50-question blocks in one sitting during your prep.
2. The "Flag" Button: If you don't know it in 45 seconds, flag it and move on. Don't burn 5 minutes on a question you will likely guess on anyway.
3. Trust Your Gut: In pattern recognition questions (Pathology, Radiology), your first instinct is usually derived from your subconscious training. Changing answers often leads to errors unless you misread the question.
4. Read the Last Sentence First: Often the vignette is long and distracting, but the question is simple: "What is the mechanism of action of the antibiotic used to treat this?"
5. Breaks: Utilize your scheduled breaks. Walk out, drink water, do some pushups. Reset your brain.

Life After the Exam

Walk out and forget it. You cannot change the answers. The result takes weeks to arrive. Enjoy the end of your residency. You have earned it.

Clinical Pearl: The most common reason for failure is Burnout, not lack of knowledge. If you are hitting a wall in June, take a full day off. A refreshed brain is worth 20 points more than an exhausted one.

Summary Checklist for Success

• Complete at least 2,500 practice questions.
• Read Miller/Review book cover-to-cover once.
• Memorize the Tumor/Pathology slides.
• Master the Basic Science equations and concepts.
• Take at least 2 full-length timed mock exams.

Good luck. You are ready.