Based on the provided case, a resident preparing for their oral boards hears senior residents reminiscing about the 'old viva' days. They describe an exam where the content varied wildly between candidates and some examiners were notoriously harsh. W

The new structured oral ensures consistent assessment content and difficulty across candidates.

A new ABOS examiner is being onboarded and is learning about the examination planning process. They are particularly interested in how the exam ensures it covers all necessary topics. According to the case, the assessment blueprint is considered an e

Ensures a representative sample of curriculum outcomes and content.

A medical education researcher is studying the effectiveness of the new structured oral examination. They are particularly interested in how the changes have improved the quality of assessment. The introduction of blueprinting, structure, and careful

Ensure fairness, consistency, validity, and reliability of the assessment.

An ABOS committee is reviewing the types of questions used in the structured oral exam. They want to ensure the questions align with the goal of probing 'higher cognitive processes.' Which of the following types of questions would BEST align with the

"A 60-year-old patient presents with progressive hip pain after THA. Given this X-ray, describe your differential diagnosis and management strategy, justifying your choices."

A group of residents is discussing the historical context of orthopedic board exams. They are trying to understand why the traditional viva voce was eventually replaced. According to the case, a significant negative consequence of the traditional viv

Terrify and stress candidates, leading to poor performance.

During a structured oral exam, one examiner begins to aggressively question a candidate, raising their voice and using intimidating language. In this situation, what specific action is the co-examiner mandated to take according to the guidelines for

Intervene immediately to stop the harassment.

An external accreditation body is reviewing the ABOS structured oral examination to ensure its quality and fairness. A key area of focus is how the exam guarantees it tests what it's supposed to test. How does the new structured oral examination prim

Through the use of a comprehensive assessment blueprint.

A resident asks their program director why the ABOS changed its oral examination format from the traditional viva to the structured oral. The primary driver for the evolution from the traditional viva voce to the new structured oral examination, as o

Improve the fairness, consistency, validity, and reliability of the assessment.

An examiner is preparing for the structured oral exam and is reflecting on the guideline that 'a good robust discussion is a grey area; it may quickly turn into a robust argument and is probably best avoided.' What is the most accurate interpretation

Examiners should be cautious and generally avoid pushing discussions to the point of potential conflict or argument.

ABOS Part I Orthopedic Board Exam Review & Oral Prep

Question 1

A candidate preparing for a high-stakes orthopedic oral examination (e.g., FRCS, AAOS, OITE) is advised to prioritize a comprehensive understanding of core orthopedic principles. Which of the following preparation strategies is MOST effective for solidifying foundational knowledge while simultaneously developing the nuanced communication skills required for an oral examination?

Explanation

Correct Answer: C

Structured, peer-led viva practice sessions are invaluable. They not only force the candidate to articulate their knowledge and reasoning aloud, mirroring the exam environment, but also allow for immediate feedback on communication style, logical flow, and depth of understanding. This active recall and explanation solidifies foundational knowledge far more effectively than passive memorization or sole reliance on past papers without the oral practice component. Commercial courses can supplement, but not replace, active personal and peer-group preparation which integrates verbalization and critical feedback.

Question 2

During an oral examination, an examiner asks a highly specialized question outside your immediate expertise. Which of the following responses is MOST appropriate and professional?

Explanation

Correct Answer: D

The most professional and constructive approach is to acknowledge the specific limitation directly but not completely shut down. Demonstrating an understanding of related foundational principles, a logical problem-solving approach, or indicating where one would seek the answer (e.g., specific literature, consultation) shows intellectual curiosity, critical thinking, and a safe approach to patient care, even when faced with an unfamiliar scenario. Bluffing or excessive apologies are detrimental to one's credibility and professionalism.

Question 3

You are presented with a simulated clinical scenario: a 45-year-old male with a displaced distal radius fracture. When asked to 'discuss your management,' which initial framework demonstrates the MOST structured and comprehensive approach expected by an examiner?

Explanation

Correct Answer: C

Examiners seek a structured, systematic approach that demonstrates a holistic understanding of patient care, not just technical surgical skills. An initial framework that covers the entire patient journey – from diagnosis (history, exam, investigations) through treatment decisions (non-op vs. op), patient communication (consent), and post-treatment considerations (post-op care, rehabilitation, complications) – demonstrates comprehensive clinical reasoning. While classification and latest research are important, they fit within this broader framework, not as the initial statement of management. Delaying an answer or over-focusing on a single aspect can suggest a lack of structured thinking.

Question 4

During your explanation of a complex surgical approach, the examiner repeatedly interrupts with challenging follow-up questions. What is the MOST effective strategy to maintain composure and demonstrate mastery?

Explanation

Correct Answer: C

Examiners often use interruptions to test a candidate's ability to think on their feet, manage pressure, and maintain a structured thought process. The most effective strategy is to acknowledge the interruption, address the specific question concisely, and then gracefully pivot back to your original, planned answer structure. This demonstrates flexibility, responsiveness, and an ability to stay organized under pressure. Ignoring or directly challenging the examiner is unprofessional and detrimental to the candidate's perceived professionalism and ability to handle pressure.

Question 5

When discussing a controversial management decision (e.g., choice of implant, timing of surgery, non-operative vs. operative) in an oral exam, how should a candidate MOST effectively integrate Evidence-Based Medicine (EBM) into their response?

Explanation

Correct Answer: C

A strong candidate in an oral exam demonstrates the ability to critically appraise and integrate EBM into clinical decision-making. This involves acknowledging areas of controversy, citing high-level evidence (e.g., landmark RCTs, systematic reviews) to support a chosen approach, and crucially, explaining how this evidence is applied or modified for the individual patient. This approach shows critical thinking, knowledge of the literature, and the ability to tailor treatment. Avoiding discussion or relying on anecdote demonstrates a lack of critical appraisal skills. Simply listing studies without synthesis is insufficient.

Question 6

An examiner asks you to 'talk me through a total hip arthroplasty.' Which aspect of your answer should you prioritize to demonstrate a comprehensive understanding, beyond just the technical steps?

Explanation

Correct Answer: C

While technical steps, biomechanics, and approaches are important, a comprehensive understanding of a procedure in an oral exam extends to the entire patient journey. Prioritizing patient selection, indications, contraindications, pre-operative planning, and post-operative care, alongside intra-operative details and complication management, demonstrates a holistic clinical perspective expected of a board-certified orthopedic surgeon. This shows an understanding of the 'why' and 'what next', not just the 'how'.

Question 7

You are presented with a difficult ethical scenario involving a patient refusing a life-saving amputation. How should you MOST appropriately structure your response?

Explanation

Correct Answer: C

Ethical dilemmas require a structured approach grounded in medical ethics. Discussing the core principles (autonomy, beneficence, non-maleficence, justice) demonstrates a foundational understanding. Crucially, assessing patient capacity to make informed decisions, exploring their reasoning, and involving a multidisciplinary team (e.g., palliative care, psychiatry, social work) and ethics committee consultation showcases a comprehensive, patient-centered, and legally sound approach to complex ethical situations. Stating personal beliefs or focusing solely on legal aspects without ethical deliberation is insufficient.

Question 8

During a viva, an examiner challenges your chosen management plan aggressively, stating 'That's not how we do things in my practice.' What is the MOST appropriate and professional response?

Explanation

Correct Answer: C

This scenario tests your ability to handle pressure, respect authority, and stand by evidence-based reasoning. The most professional approach is to respectfully acknowledge the examiner's input, demonstrate that you've heard their perspective, but then clearly and concisely reiterate the scientific rationale or evidence supporting your own plan. Offering to hear their alternative or discuss nuances demonstrates maturity and an open, learning mindset, while avoiding confrontation. Blindly agreeing or becoming defensive are both poor responses.

Question 9

When discussing potential post-operative rehabilitation for a complex orthopedic injury, what aspect should you emphasize to demonstrate a comprehensive understanding of patient recovery?

Explanation

Correct Answer: C

A comprehensive understanding of rehabilitation involves recognizing it as an integral part of the overall management plan, guided by biological healing and functional goals. A phased approach that incorporates specific milestones, addresses potential barriers (like patient compliance), and acknowledges the collaborative role of the multidisciplinary team demonstrates a holistic and practical grasp of patient recovery. Simply listing immobilization times is insufficient.

Question 10

An examiner asks a very open-ended question, such as 'Tell me about fractures around the knee.' How should you initiate your response to provide structure and depth?

Explanation

Correct Answer: C

Open-ended questions test your ability to structure a broad topic. Initiating with a categorized overview demonstrates organized thinking and control of the subject matter. It shows you can distill a vast topic into manageable sections, and then offers the examiner the opportunity to guide you to a specific area of interest, making your answer relevant and tailored. Avoiding structure or immediately narrowing the topic is less effective.

Question 11

A 45-year-old male sustains a comminuted diaphyseal tibia fracture. Which of the following factors is MOST critical in determining the rate of secondary fracture healing, assuming adequate reduction and stabilization?

Explanation

Correct Answer: E

The degree of interfragmentary strain is the most critical factor influencing secondary fracture healing, also known as callus healing. Too much strain (macromotion) disrupts the forming callus and inhibits healing, leading to non-union. Too little strain (excessive rigidity, as in primary healing) may prevent sufficient callus formation required for secondary healing. The optimal strain environment allows for the progression from hematoma to granulation tissue, soft callus, hard callus, and finally remodeling. While an intact periosteal sleeve is important for osteogenic cells, and immobilization rigidity contributes to managing strain, the degree of strain itself is the direct biomechanical determinant. Vitamin D and BMD are systemic factors but less direct than local biomechanical factors.

Question 12

A 70-year-old female falls directly onto her femur, sustaining a subtrochanteric fracture. Considering the primary load-bearing function of the femoral diaphysis, cortical bone is optimally designed to resist which type of force?

Explanation

Correct Answer: D

Cortical bone, with its dense, anisotropic structure, is strongest in compression. It has high stiffness and can withstand significant compressive loads before failure. It is weaker in tension, and even weaker in shear and torsion. Bending creates both tension and compression, so while it resists bending, its primary strength lies in resisting direct compression.

Question 13

A 30-year-old patient is immobilized for 6 weeks following a complex ankle fracture. During this period of disuse, bone remodeling shifts towards resorption, contributing to localized osteopenia. Which bone cell type is primarily responsible for sensing the altered mechanical environment and initiating these remodeling changes?

Explanation

Correct Answer: C

Osteocytes, entrapped within the bone matrix, are the primary mechanosensors of bone. They sense mechanical strain and fluid flow through their lacunar-canalicular network. This mechanotransduction initiates signaling cascades (e.g., sclerostin, RANKL) that regulate the activity of osteoblasts (bone formation) and osteoclasts (bone resorption), thereby orchestrating bone remodeling. Osteoblasts synthesize new matrix, osteoclasts resorb bone, and progenitor cells are distinct (e.g., mesenchymal stem cells). While they indirectly contribute to calcium homeostasis through remodeling, they don't directly release calcium as their primary role.

Question 14

A 65-year-old patient presents with knee osteoarthritis, characterized by progressive loss of articular cartilage. The primary proteoglycan responsible for the cartilage's ability to resist compressive loads, and whose degradation is central to osteoarthritis, is:

Explanation

Correct Answer: C

Aggrecan is the major proteoglycan in articular cartilage and is critical for its compressive stiffness. Aggrecan molecules aggregate with hyaluronic acid, forming large complexes that trap water within the collagen network. This creates a high osmotic swelling pressure, which resists compression by forcing water out, providing load-bearing capacity and resilience. Decorin, Biglycan, Versican, and Fibromodulin are smaller proteoglycans with different roles, such as collagen fibril organization or cell signaling, but not the primary role in compressive strength.

Question 15

A 35-year-old male sustains a spiral fracture of the mid-shaft femur. He undergoes intramedullary nailing. Which of the following biomechanical principles BEST explains why a long intramedullary nail is effective in stabilizing this diaphyseal fracture?

Explanation

Correct Answer: D

An intramedullary nail is highly effective in stabilizing diaphyseal fractures primarily by resisting torsional and bending forces along the length of the diaphysis. This is crucial for long bone fractures, which are frequently subjected to these types of loads during daily activities. While an intramedullary nail also acts as a load-sharing device, allowing for controlled micromotion conducive to secondary (callus) bone healing, its direct mechanical effectiveness in preventing rotation and angulation is paramount for stabilization.

Question 16

A pediatric patient presents with a growth plate injury. Understanding the biology of endochondral ossification, the primary role of Type X collagen is associated with which zone of the physis?

Explanation

Correct Answer: C

Type X collagen is specifically expressed by chondrocytes in the hypertrophic zone of the growth plate. It plays a crucial role in cartilage maturation, mineralization, and vascular invasion, signaling the transition from cartilage to bone. It is considered a marker of terminal chondrocyte differentiation and hypertrophy. The other zones have different primary collagen types and functions (e.g., Type II in resting and proliferative zones).

Question 17

A patient sustains a complete transection of the ulnar nerve at the elbow. When discussing the prognosis for nerve regeneration, it is important to understand that Wallerian degeneration, the process of axonal degeneration distal to the injury, typically begins how long after axon transection?

Explanation

Correct Answer: D

Wallerian degeneration, the process of axonal degeneration distal to a site of injury, typically begins within 24-48 hours after axon transection. While some changes might be observed earlier, the complete breakdown of the axon and myelin sheath becomes evident within this timeframe. This process clears the debris to allow for potential regeneration, especially in the peripheral nervous system.

Question 18

A 40-year-old male presents with acute low back pain radiating down his leg, consistent with a posterolateral disc herniation. From a biomechanical perspective, what is the primary function of the annulus fibrosus that is compromised in this condition?

Explanation

Correct Answer: B

The annulus fibrosus consists of concentric lamellae of collagen fibers (predominantly Type I) arranged obliquely. Its primary function is to contain the nucleus pulposus and provide significant tensile strength, especially against torsional and bending forces. While the nucleus pulposus bears axial compressive loads through hydrostatic pressure, the annulus resists the radial expansion of the nucleus under compression and helps stabilize the vertebral segment by resisting tensile forces in various directions. It is the outer containment system.

Question 19

A 72-year-old female with severe osteoporosis is being considered for denosumab therapy. Understanding its mechanism of action, which cytokine is a potent stimulator of osteoclastogenesis and bone resorption, and is directly targeted by denosumab?

Explanation

Correct Answer: C

RANKL (Receptor Activator of Nuclear Factor kappa-B Ligand) is a key cytokine that binds to RANK receptors on pre-osteoclasts and mature osteoclasts, stimulating their differentiation, activation, and survival, thereby promoting bone resorption. Denosumab is a monoclonal antibody that targets and inhibits RANKL, making it a powerful antiresorptive agent. TGF-β and BMP-2 are more involved in bone formation, IL-6 has diverse inflammatory roles, and PTHrP is involved in endochondral ossification and hypercalcemia of malignancy.

Question 20

A 28-year-old athlete sustains a meniscal tear in his knee. Understanding the normal function of the menisci, which of the following is considered their primary biomechanical role in the knee joint?

Explanation

Correct Answer: B

The menisci are C-shaped fibrocartilaginous structures that sit on the tibial plateau. Their primary biomechanical roles include increasing the contact area between the femoral condyles and tibial plateau, which significantly reduces contact stress on the articular cartilage. They also contribute to joint stability, shock absorption, and some lubrication, but increasing congruity and reducing stress are their most critical functions. Ligaments limit hyperextension and provide varus/valgus stability.

Question 21

A 35-year-old male sustains an anteroposterior compression type II (APC-II) pelvic ring injury. Which of the following ligaments is torn in this specific injury pattern, distinguishing it from an APC-I injury?

Explanation

In an APC-II injury, the pubic diastasis is greater than 2.5 cm, and the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments are disrupted. The posterior sacroiliac ligaments remain intact, providing vertical stability.

Question 22

A 13-year-old obese male presents with acute on chronic slipped capital femoral epiphysis (SCFE). He undergoes in situ pinning. Which of the following is the most common complication following this procedure for an unstable SCFE?

Explanation

Avascular necrosis is the most devastating and relatively common complication following an unstable SCFE, occurring in up to 47% of cases. Chondrolysis is more commonly associated with unrecognized hardware penetration into the joint.

Question 23

A 25-year-old carpenter suffers a laceration to the volar aspect of his index finger at the level of the proximal interphalangeal (PIP) joint. Examination reveals inability to flex both the PIP and DIP joints. What zone of flexor tendon injury does this represent?

Explanation

Zone II, historically known as 'no man's land', extends from the A1 pulley to the insertion of the flexor digitorum superficialis (FDS) on the middle phalanx. Injuries here typically involve both the FDS and FDP tendons and carry a high risk of adhesions.

Question 24

A 15-year-old boy presents with a permeative lytic lesion in the diaphysis of his femur with an associated onion-skin periosteal reaction. Cytogenetic analysis reveals a t(11;22) translocation. Which of the following fusion proteins is highly characteristic of this tumor?

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. The t(11;22) chromosomal translocation is found in approximately 85% of Ewing sarcomas and results in the EWS-FLI1 fusion protein.

Question 25

A 45-year-old active male underwent a total hip arthroplasty with a ceramic-on-ceramic bearing. Two years postoperatively, he complains of a new-onset squeaking noise from the hip during gait, without pain. What is the most significant risk factor for this phenomenon?

Explanation

Squeaking is a known complication of ceramic-on-ceramic bearings, occurring in up to 10% of patients. It is most strongly associated with edge loading due to acetabular component malposition, such as excessive anteversion or inclination.

Question 26

A 65-year-old male presents with deteriorating fine motor skills in his hands and a broad-based gait. Physical examination shows positive Hoffman and Babinski signs. Sagittal T2 MRI reveals cervical spinal cord compression at C4-C5 with a hyperintense intramedullary signal. What does this signal change indicate regarding his prognosis?

Explanation

A hyperintense intramedullary T2 signal in the context of cervical spondylotic myelopathy typically represents cord edema, gliosis, or myelomalacia. It correlates with a worse preoperative functional status and poorer postoperative neurological recovery.

Question 27

When performing an anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone (BPTB) autograft, which of the following complications is significantly more common compared to using a hamstring autograft?

Explanation

BPTB autografts are historically associated with a higher incidence of donor-site morbidity, specifically anterior knee pain and pain with kneeling, compared to hamstring autografts. Rates of graft failure are generally comparable between the two.

Question 28

A 55-year-old diabetic patient presents with an acutely swollen, erythematous, and warm foot but no systemic signs of infection. Radiographs show periarticular debris, fragmentation of the tarsometatarsal joints, and subluxation. According to the Eichenholtz classification, what stage does this represent, and what is the preferred initial management?

Explanation

This presentation describes Eichenholtz Stage 1 (development/fragmentation) of Charcot arthropathy. The gold standard initial management is offloading via total contact casting to prevent further deformity while the acute inflammatory phase resolves.

Question 29

Which mechanism of wear is most responsible for the generation of submicron polyethylene particles that precipitate osteolysis in conventional ultra-high-molecular-weight polyethylene (UHMWPE) total hip arthroplasty components?

Explanation

Adhesive wear is the primary mechanism generating millions of submicron UHMWPE particles (0.1 to 1.0 microns) that are easily phagocytosed by macrophages. This initiates the biological cascade leading to osteolysis and aseptic loosening.

Question 30

A 40-year-old male sustains a high-energy Schatzker VI tibial plateau fracture. Which of the following is the most appropriate initial management to minimize soft tissue complications while providing skeletal stability?

Explanation

High-energy tibial plateau fractures (Schatzker VI) are associated with severe soft tissue compromise. The standard of care is temporary spanning external fixation to allow soft tissues to recover before definitive open reduction and internal fixation.

Question 31

A 4-month-old female with developmental dysplasia of the hip (DDH) has been treated with a Pavlik harness for 4 weeks. Ultrasound demonstrates continued posterior dislocation of the femoral head with no reduction. What is the most appropriate next step in management?

Explanation

Failure to achieve reduction in a Pavlik harness within 3 to 4 weeks is an indication to abandon the harness to prevent Pavlik harness disease (posterior acetabular erosion). The standard next step is closed reduction and spica casting under anesthesia.

Question 32

According to the Musculoskeletal Infection Society (MSIS) and International Consensus Meeting (ICM) criteria, which of the following findings is considered a definitive major criterion for diagnosing a periprosthetic joint infection (PJI)?

Explanation

The two major criteria for definitive diagnosis of PJI are the presence of a sinus tract communicating with the prosthesis and the isolation of the same microorganism from two or more distinct cultures obtained from the affected joint.

Question 33

A 22-year-old male sustains a proximal pole scaphoid fracture. Which of the following best explains the high risk of avascular necrosis (AVN) and nonunion associated with this specific fracture pattern?

Explanation

The scaphoid has a retrograde blood supply. The major vascular contribution enters the dorsal ridge at the waist and distal pole, flowing proximally. Therefore, proximal pole fractures interrupt this supply, leading to a high rate of AVN.

Question 34

A 45-year-old female presents with acute medial knee pain after a squatting injury. MRI reveals a complete radial tear of the medial meniscus posterior root. Biomechanically, this injury is equivalent to which of the following?

Explanation

A complete medial meniscus posterior root tear disrupts the hoop stresses of the meniscus, leading to extrusion under load. Biomechanically, it alters contact pressures in the medial compartment to a degree equivalent to a total medial meniscectomy.

Question 35

A 45-year-old male is brought to the ED after a motorcycle collision. He has an anteroposterior compression (APC) type III pelvic ring injury and blood at the urethral meatus. According to ATLS and oral board management protocols, what is the MOST appropriate next step in evaluating the urogenital tract?

Explanation

Blood at the urethral meatus is a cardinal sign of urethral injury, which is common in anterior pelvic ring disruptions. A retrograde urethrogram must be performed to evaluate urethral integrity before any attempt at passing a urethral catheter.

Question 36

During an oral examination, you are presented with a 12-year-old obese male complaining of chronic left knee pain. Physical exam reveals obligatory external rotation of the left hip during passive hip flexion. Which of the following radiographic findings is MOST characteristic of this condition?

Explanation

The clinical presentation is classic for a Slipped Capital Femoral Epiphysis (SCFE). On the AP pelvis radiograph, the Trethowan sign is positive when Klein's line (drawn along the superior femoral neck) fails to intersect the lateral portion of the femoral epiphysis.

Question 37

A 65-year-old female presents with progressive hand clumsiness, gait instability, and hyperreflexia. Imaging demonstrates 3-level cervical spondylotic myelopathy with a fixed, rigid kyphotic deformity of 15 degrees. What is the MOST appropriate surgical management?

Explanation

In cases of multi-level cervical myelopathy with a rigid kyphotic deformity, an anterior approach is necessary to decompress the spinal cord and correct the kyphosis. A combined anterior-posterior approach provides the best biomechanical stability for rigid, multi-level kyphotic deformities.

Question 38

A 70-year-old female presents with her third posterior dislocation 4 weeks after a primary total hip arthroplasty (THA). Radiographs and CT demonstrate the acetabular component is placed in 10 degrees of retroversion and 40 degrees of abduction. The femoral component is well-fixed with 15 degrees of anteversion. What is the definitive management?

Explanation

The patient has recurrent posterior instability due to acetabular retroversion (malposition). The definitive treatment is revision of the acetabular component to achieve proper anteversion (typically 15-20 degrees) to restore stability.

Question 39

A 25-year-old carpenter sustains a laceration to the volar aspect of his index finger, severing the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) in Zone II. Primary repair is performed. Which of the following rehabilitation protocols emphasizes early passive flexion and passive extension to minimize adhesions?

Explanation

The Duran protocol relies on passive flexion and passive extension exercises to prevent tendon adhesions following flexor tendon repair. In contrast, the Kleinert protocol utilizes dynamic traction via rubber bands for passive flexion and active extension.

Question 40

A 22-year-old collegiate football player sustains an anterior shoulder dislocation. Advanced imaging reveals an engaging Hill-Sachs lesion and 25% anterior glenoid bone loss. Which of the following surgical procedures is MOST appropriate to restore stability?

Explanation

Critical anterior glenoid bone loss combined with an engaging Hill-Sachs lesion is a high-risk scenario for recurrent instability after soft tissue repair alone. The Latarjet procedure (coracoid transfer) is the standard of care to restore the glenoid bone arc and provide a sling effect.

Question 41

Aspirin is often used for deep vein thrombosis (DVT) prophylaxis following total joint arthroplasty. What is the primary mechanism of action of aspirin in this clinical context?

Explanation

Aspirin acts by irreversibly inhibiting the cyclooxygenase-1 (COX-1) enzyme, which prevents the production of thromboxane A2 and inhibits platelet aggregation for the lifespan of the platelet. This provides effective and cost-efficient DVT prophylaxis in appropriate orthopedic patients.

Question 42

A 15-year-old male presents with persistent knee pain. Radiographs demonstrate a destructive, mixed lytic and sclerotic lesion in the distal femoral metaphysis with a sunburst periosteal reaction. Core needle biopsy confirms high-grade intramedullary osteosarcoma. What is the standard sequence of treatment?

Explanation

The standard of care for high-grade osteosarcoma is neoadjuvant (preoperative) chemotherapy, followed by wide surgical resection (limb salvage or amputation), and then adjuvant (postoperative) chemotherapy. Radiation plays a minimal role because osteosarcoma is highly radioresistant.

Question 43

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the parents report the infant is no longer actively kicking the affected leg. On examination, the hip is held in excessive hyperflexion. Which nerve is most likely compressed?

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness when the hip is placed in excessive hyperflexion. If this occurs, the harness must be removed or adjusted immediately to allow nerve recovery.

Question 44

A 28-year-old male is brought to the trauma bay after a motorcycle accident. He is hemodynamically unstable with a blood pressure of 80/40 mmHg. FAST exam is negative. Pelvic radiograph shows an anteroposterior compression type III (APC III) injury. A pelvic binder is applied, but the patient remains persistently hypotensive despite aggressive fluid resuscitation. What is the MOST appropriate next step in management?

Explanation

In a hemodynamically unstable patient with a mechanically unstable pelvic ring injury and a negative FAST exam, the bleeding is presumed to be retroperitoneal. After applying a pelvic binder, persistent instability requires either angiography with embolization or preperitoneal pelvic packing based on institutional protocols.

Question 45

During an ABOS oral exam, you are presented with a 65-year-old female who is 8 years status post a metal-on-metal total hip arthroplasty. She complains of new-onset groin pain and a palpable mass. Laboratory studies show significantly elevated serum cobalt and chromium levels. Which of the following imaging modalities is MOST appropriate to evaluate the extent of the suspected adverse local tissue reaction (ALTR)?

Explanation

MARS MRI is the gold standard for evaluating adverse local tissue reactions (ALTR) or pseudotumors around metal-on-metal implants. It clearly defines the soft tissue mass, fluid collections, and the extent of muscle destruction, which is critical for preoperative planning.

Question 46

A 15-year-old male sustains a twisting injury to his knee. Plain radiographs demonstrate an avulsion fracture of the lateral tibial plateau (Segond fracture). In a clinical oral examination, you are asked about the biomechanical implications of this finding. A Segond fracture is pathognomonic for a tear of the anterior cruciate ligament (ACL) and is highly associated with injury to which of the following structures?

Explanation

A Segond fracture is a bony avulsion of the anterolateral capsule and is considered pathognomonic for an ACL tear. It is heavily associated with concurrent injury to the anterolateral ligament (ALL), which contributes to anterolateral rotatory instability.

Question 47

You are evaluating a 12-year-old obese boy who presents with inability to bear weight on his right leg after a minor fall. Radiographs reveal a severe, displaced slipped capital femoral epiphysis (SCFE). Which of the following factors represents the GREATEST risk for the development of avascular necrosis (AVN) in this patient?

Explanation

The clinical stability of the slip, defined as the ability to bear weight with or without crutches, is the greatest predictor of AVN. Unstable SCFE has an AVN risk of up to 50%, whereas stable SCFE has a nearly zero risk.

Question 48

A 22-year-old mechanic sustains a scaphoid proximal pole fracture. He is informed that this fracture is at high risk for nonunion and avascular necrosis. The examiner asks you to explain the anatomic basis for this risk. Which of the following best describes the predominant vascular supply to the scaphoid?

Explanation

The scaphoid receives 70-80% of its blood supply from the dorsal carpal branch of the radial artery, which enters distally and flows retrograde to the proximal pole. This retrograde perfusion leaves proximal pole fractures highly susceptible to avascular necrosis and nonunion.

Question 49

A 45-year-old male sustains a burst fracture of the C1 ring (Jefferson fracture) after diving into shallow water. Open mouth odontoid radiographs demonstrate bilateral lateral mass overhang. According to the Rule of Spence, what is the critical threshold of combined lateral mass overhang that strongly suggests a transverse ligament rupture?

Explanation

The Rule of Spence states that a combined C1 lateral mass overhang on C2 of 6.9 mm or greater on an open-mouth odontoid radiograph indicates a rupture of the transverse ligament. This renders the C1-C2 articulation highly unstable, often requiring halo immobilization or surgical fusion.

Question 50

A 30-year-old polytrauma patient presents with bilateral femur fractures and a severe closed head injury. His initial arterial lactate is 5.2 mmol/L, base deficit is -8, and pH is 7.21. In the context of Damage Control Orthopedics (DCO), what is the MOST appropriate initial management for his femur fractures?

Explanation

This patient is physiologically unstable (elevated lactate, severe base deficit, acidosis) and has a severe head injury. Early Total Care (intramedullary nailing) could exacerbate the systemic inflammatory response and secondary brain injury, making rapid external fixation (Damage Control Orthopedics) the safest initial step.

Question 51

During an oral boards oncology scenario, you are presented with a radiograph of a 16-year-old with a destructive, mixed lytic and sclerotic metaphyseal lesion of the distal femur with a Codman's triangle. A biopsy confirms osteosarcoma. What is the standard, evidence-based sequence of treatment for non-metastatic high-grade extremity osteosarcoma?

Explanation

The standard of care for high-grade, non-metastatic extremity osteosarcoma is neoadjuvant (preoperative) chemotherapy, followed by wide surgical resection, and then adjuvant (postoperative) chemotherapy. Radiation is generally not a primary modality as osteosarcoma is relatively radioresistant.

Question 52

A 25-year-old collegiate football player sustains a purely ligamentous Lisfranc injury. Weight-bearing radiographs demonstrate 3 mm of widening between the medial cuneiform and the base of the second metatarsal. Based on recent high-level evidence, what is the favored operative management for a purely ligamentous Lisfranc injury to minimize the need for subsequent revision surgery?

Explanation

Recent prospective randomized studies indicate that primary arthrodesis of the involved tarsometatarsal joints for purely ligamentous Lisfranc injuries yields superior functional outcomes and a lower revision rate compared to ORIF.

Question 53

Recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) is utilized in spine fusion and open tibia fractures. When an examiner asks about its cellular mechanism of action, you correctly state that BMP-2 initiates osteoinduction primarily by binding to cell surface receptors and subsequently activating which intracellular signaling pathway?

Explanation

BMP-2 binds to serine/threonine kinase receptors on mesenchymal stem cells, which phosphorylates and activates the intracellular SMAD 1/5/8 complex. This complex translocates to the nucleus to upregulate osteogenic genes like Runx2.

Question 54

A 35-year-old carpenter suffers a laceration to the volar aspect of his index finger, resulting in a Zone II flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) transection. To allow for a safe early active motion rehabilitation protocol, the core suture repair of the FDP tendon should have a MINIMUM of how many strands across the repair site?

Explanation

Biomechanical studies have demonstrated that a minimum of a 4-strand core repair (often combined with an epitendinous suture) is necessary to provide the tensile strength required to safely withstand an early active motion protocol without gap formation or rupture.

Question 55

During a total knee arthroplasty on a patient with a severe fixed valgus deformity, you find that the lateral collateral ligament (LCL) and posterolateral corner remain tight in extension after your bony cuts. When sequentially releasing structures to balance a valgus knee in extension, which structure is typically released first?

Explanation

In the standard sequence for balancing a fixed valgus knee in extension, the iliotibial (IT) band is typically the first structure released (often via pie-crusting), followed by the posterolateral capsule, and then the popliteus or LCL if further correction is needed.

Question 56

You are discussing a complication case during your ABOS Part II oral exam. A patient developed a deep surgical site infection following an open reduction internal fixation of a pilon fracture. Which of the following responses is the MOST professional and safe way to frame your initial management approach?

Explanation

Oral board examiners look for candidate accountability, patient safety, and structured problem-solving. Admitting the complication, taking personal responsibility, and detailing an aggressive, safe management plan (cultures and surgical debridement) demonstrates mature, board-level competency.

Question 57

A 6-year-old boy falls from monkey bars and presents with a Gartland Type III supracondylar humerus fracture. On exam, the hand is pink but the radial pulse is absent. After emergent closed reduction and percutaneous pinning in the operating room, the hand remains pink, capillary refill is brisk, but the radial pulse is still absent on Doppler. What is the most appropriate next step in management?

Explanation

For a 'pulseless but pink' hand after anatomic reduction and stabilization of a pediatric supracondylar humerus fracture, the standard of care is close clinical observation. The collateral circulation is sufficient for hand viability, and the radial pulse often returns over time.

Question 58

A 40-year-old male sustains a posterior shoulder dislocation following a seizure. CT scan reveals an anteromedial humeral head impaction fracture (reverse Hill-Sachs lesion) that involves 45% of the articular surface. Which of the following surgical interventions is MOST appropriate for this patient?

Explanation

Management of a reverse Hill-Sachs lesion depends on the size of the articular defect. Defects <20% can often be observed; 20-40% are treated with subscapularis/lesser tuberosity transfer; and defects >40% typically require arthroplasty to restore joint stability and congruency.

Question 59

A 35-year-old motorcyclist sustains a Gustilo-Anderson Type IIIB open tibia fracture. Initial management in the trauma bay includes antibiotics, tetanus prophylaxis, and a temporary splint. What is the single most important factor in decreasing the risk of deep infection in this patient?

Explanation

Extensive literature confirms that the most critical variable in reducing infection rates in open fractures is the early administration of systemic antibiotics, ideally within 1 to 3 hours of injury.

Question 60

During a pathology review section, you are shown a histology slide of a bone tumor revealing uniform, small, round blue cells with scant cytoplasm. Cytogenetics reveals a t(11;22) chromosomal translocation. Which fusion gene is characteristically produced by this translocation?

Explanation

Ewing sarcoma is classically characterized by the t(11;22)(q24;q12) translocation, which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11, forming the EWS-FLI1 fusion protein.

Question 61

When evaluating a patient with suspected Carpal Tunnel Syndrome (CTS), you perform several clinical exams. Which of the following physical examination modalities is considered the most SENSITIVE for detecting early sensory nerve compression in CTS?

Explanation

Semmes-Weinstein monofilament testing assesses the threshold of sensory perception and is widely considered the most sensitive clinical test for detecting early nerve compression and sensory loss in carpal tunnel syndrome.

Question 62

A 6-month-old female with developmental dysplasia of the hip (DDH) has failed 6 weeks of Pavlik harness treatment. Ultrasound confirms persistent dislocation of the left hip. What is the MOST appropriate next step in management?

Explanation

When a Pavlik harness fails to achieve reduction in an infant with DDH around 6 months of age, the next standard step is an examination under anesthesia, arthrogram, and attempted closed reduction followed by spica cast application.

Question 63

You are questioned about the physiology of fracture healing following the application of a dynamic compression plate (rigid internal fixation). This construct relies on which of the following mechanisms to achieve union?

Explanation

Rigid internal fixation with absolute stability minimizes interfragmentary strain, bypassing callus formation. It instead promotes primary (direct) bone healing, which occurs via osteoclast cutting cones and subsequent osteoblast-mediated Haversian remodeling.

Question 64

A 28-year-old male sustains a Hawkins Type III fracture of the talar neck after a fall from a height. Which of the following best describes the expected rate of avascular necrosis (AVN) of the talar body and the mechanism of disrupted blood supply?

Explanation

Hawkins Type III fractures involve the talar neck with subtalar and tibiotalar dislocation, disrupting all three major blood supplies to the talar body. The AVN rate approaches 80-100% in these injuries.

Question 65

A 6-year-old boy presents with a completely displaced, extension-type supracondylar humerus fracture. The hand is pink, but the radial pulse is absent. After urgent closed reduction and percutaneous pinning, the hand remains pink and warm, but the pulse is still non-palpable. What is the most appropriate next step in management?

Explanation

A "pink, pulseless" hand following reduction and pinning of a pediatric supracondylar humerus fracture is well-perfused through collateral circulation. The standard of care is close observation and monitoring, as the pulse often returns within 24-48 hours.

Question 66

A 65-year-old male presents with deteriorating handwriting, frequent stumbling, and bilateral hand numbness. Physical exam reveals a positive Hoffmann sign and sustained ankle clonus. An MRI shows severe cervical stenosis at C4-C5. During an oral exam, you are asked about the primary goal of surgical intervention. What is the most accurate response?

Explanation

The primary goal of surgery in cervical spondylotic myelopathy is to halt disease progression and prevent further neurologic decline. While some patients may experience functional improvement, reversing existing deficits cannot be guaranteed.

Question 67

Six months after a total knee arthroplasty, a 70-year-old patient presents with a draining sinus tract communicating with the joint. What is the gold standard surgical management for this presentation?

Explanation

A draining sinus tract communicating with the prosthesis is a definitive sign of chronic periprosthetic joint infection. The gold standard treatment in North America is a two-stage revision arthroplasty.

Question 68

A 32-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion extending to the subchondral bone of the distal femur. Biopsy confirms a Giant Cell Tumor of bone. If medical therapy is considered to facilitate joint-salvage surgery, which medication is most appropriate and what is its mechanism?

Explanation

Giant cell tumors of bone consist of neoplastic stromal cells that express RANKL, which recruits osteoclast-like giant cells. Denosumab is a monoclonal antibody against RANKL used to consolidate the tumor prior to curettage or resection.

Question 69

A 22-year-old female soccer player undergoes an anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone (BTB) autograft. Compared to a hamstring autograft, which of the following complications is significantly more common with this graft choice?

Explanation

Bone-patellar tendon-bone autografts are associated with a higher incidence of donor site morbidity, specifically anterior knee pain and pain with kneeling, compared to hamstring autografts. Graft rupture rates are comparable or slightly lower for BTB.

Question 70

During an oral board examination, you are presented with a case where you intraoperatively realize you have placed a pedicle screw into the spinal canal, causing a neurologic deficit. The examiner asks how you will communicate this to the patient postoperatively. What is the most appropriate approach?

Explanation

Honesty, transparency, and empathy are hallmarks of professional medical practice and are strictly evaluated in oral board exams. Full disclosure of medical errors, accompanied by an apology and a concrete action plan, is the only acceptable response.

Question 71

You are explaining the rationale for using a compression plate for a transverse radius fracture. Absolute stability constructs, such as compression plating, promote which type of bone healing, and what is the primary prerequisite?

Explanation

Absolute stability constructs prevent micromotion and rely on anatomic reduction to achieve primary (direct) bone healing. This process occurs via cutting cones crossing the fracture site without the formation of a visible fracture callus.

Question 72

A 25-year-old carpenter sustains a laceration over the proximal phalanx of the index finger, resulting in an inability to flex the DIP and PIP joints. In which flexor tendon zone is this injury, and why has this zone historically been termed "no man's land"?

Explanation

Zone II extends from the A1 pulley to the FDS insertion. It was historically called "no man's land" due to the high rate of postoperative adhesions between the FDS, FDP, and the flexor sheath, leading to predictably poor functional outcomes.

Question 73

A 40-year-old male weekend warrior sustains an acute Achilles tendon rupture. When discussing operative versus non-operative management in a highly structured board setting, what is the most accurate statement regarding outcomes based on recent prospective randomized trials?

Explanation

Recent Level I evidence shows that when early functional rehabilitation (early weight-bearing and ROM) is employed, re-rupture rates are not significantly different between operative and non-operative groups. However, surgery continues to carry a higher risk of wound complications.

Orthopaedic Surgery Board Exam Review: ABOS Part I & AAOS OITE Prep Questions | Part 22210

ABOS Part I Comprehensive Orthopedic Board Exam Review & Oral Exam Prep | Part 22166

Key Takeaway

ABOS Part I Comprehensive Orthopedic Board Exam Review & Oral Exam Prep | Part 22166

Chapter Index