- Part I is 250 MCQs across three 120-minute sections - six hours of testing plus two optional 15-minute breaks.
- Written exam fee is $1,000; first-time AOAO resident members can cut it to $500 with the coupon.
- Passing score is a fixed 500 on a 200-800 scale, not a moving percentile target.
- Basic Science (12-16%) is the single largest domain - larger than Joint or Trauma alone.
Exam Snapshot at a Glance
This cheat sheet covers the American Osteopathic Board of Orthopedic Surgery (AOBOS) Part I Written Exam - the initial certification exam, not the separate Clinical Exam or the ongoing longitudinal assessment. If you're prepping for Part I, keep this page open alongside your notes as a fast-reference check before you dive into deeper resources like the Orthopedic Surgery Study Guide.
| Item | Detail |
|---|---|
| Question count | 250 multiple-choice questions |
| Structure | Three 120-minute sections |
| Total testing time | Six hours active + two optional 15-minute breaks (6h30m including breaks) |
| Written exam fee | $1,000 (first-time AOAO resident members: $500 with coupon) |
| Passing score | 500 on a 200-800 scale |
| Application window | Opens October; first deadline first business day in March, final deadline first business day in April |
| Exam window | Second week of May, annually |
Domain Breakdown: All 10 Content Areas
The written exam draws from ten domains, each with an official percentage range. These ranges are intentionally not equal-weighted, so your study time shouldn't be either. For the full walkthrough of each area, see the Orthopedic Surgery Exam Domains Guide.
Domain 10: Basic Science (12-16%)
The largest single domain. Expect questions on bone healing, biomechanics, pharmacology, and musculoskeletal physiology that underpin clinical decisions in every other domain.
- Highest-weighted area - never leave it for "later"
Domain 3: Joint (11-14%) and Domain 7: Trauma (11-14%)
These tie as the second-largest domains. Joint covers arthroplasty and degenerative pathology; Trauma covers fracture patterns, fixation strategy, and acute management decisions.
- Combined, Joint and Trauma can outweigh Basic Science in a given exam form
Domain 5: Sports Medicine (11-13%)
Ligamentous and soft-tissue injury, scope-based procedures, and return-to-play decision-making.
Domain 1: Foot/Ankle (10-11%) and Domain 2: Hand/Upper Extremity (10-12%)
Both are mid-weighted regional domains testing anatomy-specific pathology and operative indications.
Domain 4: Pediatrics (9-11%) and Domain 6: Spine (9-11%)
Growth-plate and deformity questions dominate Pediatrics; degenerative and deformity spine pathology dominates Spine.
Domain 8: Tumor (4-6%) and Domain 9: Infection (5-6%)
The two smallest domains combined make up roughly a tenth of the exam, but musculoskeletal oncology and periprosthetic infection questions are still fair game and easy to under-prepare.
Fees, Eligibility, and Deadlines
Fee mechanics and eligibility rules trip up more candidates than content gaps. Here's the mechanic, not just the number - full breakdown at Orthopedic Surgery Certification Cost and Orthopedic Surgery Requirements.
- Written exam fee: $1,000 standard. First-time AOAO resident members can request a $500 coupon, bringing the fee to $500.
- Clinical Exam fee (separate certification stage): $2,250, with a $250 late fee after the first deadline. This is not part of the Part I written fee.
- Eligibility path: Graduation from an ACGME-accredited orthopedic surgery residency, or current PGY-4/PGY-5 status. PGY-4 applicants need program-director approval.
- Other requirements: Meeting AOBOS application and ethics standards.
- Application timeline: Opens in October; first deadline is the first business day in March; final deadline is the first business day in April.
- Exam date: Second week of May, once per year.
For the precise sequence of open dates, deadlines, and exam week, check Orthopedic Surgery Exam Dates 2026.
Key Takeaway
If you're a PGY-4, secure program-director approval early - it's a prerequisite step, not a formality, and it needs to be in place before the March/April deadlines.
Scoring and What Counts as Passing
The passing score is fixed at 500 on a 200-800 scaled range. This is a scaled score, not a raw percentage - the underlying difficulty of your specific form is already accounted for. Details on how scaling works and what it means for borderline scores are covered in the Orthopedic Surgery Passing Score guide.
Note also that the widely cited 98.2% figure is a five-year aggregate pass rate for first-time board-eligible examinees - it is not a single-year statistic, and it shouldn't be read as "98.2% of any one year's cohort passed." For a deeper look at how that number is calculated and what it implies about difficulty, see the Orthopedic Surgery Pass Rate breakdown and the companion piece on How Hard Is the Orthopedic Surgery Exam.
Exam Day Mechanics
Part I is delivered under remote-proctoring arrangements through AOA MonitorEDU/PARADIGM. Know these mechanics before exam week so nothing is a surprise:
- Environment: A private testing room, free of interruptions and other people.
- Equipment: A compatible computer and mobile device, plus the required secure browser installed and technical checks completed ahead of time.
- Tools provided: An online calculator, scratch pad, and laboratory values are supplied within the testing platform.
- Physical aids: Whiteboards are permitted.
- Timing: Three 120-minute sections, six hours of active testing, plus two optional 15-minute breaks - total time in the seat can run to six hours 30 minutes.
After Part I: Clinical Exam and OCC
Passing Part I is one stage, not the finish line. Full certification requires the separate Clinical Exam ($2,250, $250 late fee after the first deadline), which includes surgical-practice documentation and oral defense of selected cases, followed by AOA approval.
Once certified, diplomates in Osteopathic Continuous Certification (OCC) must maintain active licensure, accumulate CME, complete longitudinal assessment, and attest to quality-improvement activity.
- 2025-2027 CME cycle: 60 CME credits total, including 15 Category 1-A credits, for time-limited and participating OCC diplomates.
- Longitudinal assessment: Replaced the traditional ten-year high-stakes exam in 2021. It's $230 annually, 15 untimed, open-book, article-based questions drawn from three of nine assessment areas.
- Passing threshold: 80%, with a second attempt available before the end-of-July deadline.
- Availability window: May through July each year.
- Grace period: Newly certified diplomates get one full calendar year without required assessment participation.
Important: the nine renewal-assessment areas are a distinct list from the ten initial written-exam domains covered above - don't assume overlap in content weighting.
Where to Spend Your Study Hours
Given the domain weights, a simple rule works well: spend roughly proportional time to percentage weight, with a floor for the smallest domains so they aren't skipped entirely.
Basic Science + Joint
- Start with the two highest-leverage domains: Basic Science (12-16%) and Joint (11-14%)
Trauma + Sports Medicine
- Trauma (11-14%) and Sports Medicine (11-13%) - fixation logic and soft-tissue injury patterns
Foot/Ankle + Hand/Upper Extremity
- Regional anatomy domains at 10-12% each
Pediatrics + Spine
- 9-11% each - growth-plate and deformity-focused review
Tumor + Infection + Full Timed Blocks
- Cover the smallest domains (4-6% and 5-6%), then run full 120-minute timed practice sections
If you want a more detailed methodology - spaced review cycles, question-bank rotation, and how to interleave domains rather than study them in isolation blocks - that's covered separately in the full study guide. For a broader question bank experience under timed conditions, practicing on the main practice test platform before exam week is one of the most direct ways to simulate the real three-section format.
Key Takeaway
Don't treat all ten domains equally. Basic Science, Joint, Trauma, and Sports Medicine together account for a large share of the exam - master those first, then round out the regional and low-weight domains.
FAQ
250 multiple-choice questions, split across three 120-minute sections, for six hours of active testing time.
The standard fee is $1,000. First-time AOAO resident members can request a coupon that reduces the fee to $500. This is separate from the $2,250 Clinical Exam fee, which carries its own $250 late charge after the first deadline.
A scaled score of 500 on a 200-800 range. See the passing score guide for more on how scaling works.
Basic Science, at 12-16%, is the single largest domain, followed closely by Joint and Trauma at 11-14% each. These three collectively represent the highest-yield study time.
Yes, with program-director approval. PGY-5 status and residency graduation from an ACGME-accredited orthopedic surgery program are the other qualifying eligibility paths, alongside meeting AOBOS application and ethics requirements.
No. Part I is the written exam stage. Full certification also requires passing the separate Clinical Exam - including surgical-practice documentation and oral defense of cases - followed by AOA approval.