This practice set contains high-yield board review questions covering key concepts in 3. Adult Reconstruction (Hip & Knee). Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 2001
Topic: Total Hip Arthroplasty (THA)
A 45-year-old active male underwent a ceramic-on-ceramic total hip arthroplasty 2 years ago. He now complains of a squeaking noise with deep flexion. Which of the following component factors is most strongly associated with this phenomenon?
Correct Answer & Explanation
. Acetabular component placed in >50 degrees of abduction
Explanation
Squeaking in ceramic-on-ceramic bearings is strongly associated with edge loading. This typically occurs when the acetabular component is placed in excessive abduction (>50 degrees) or malversion, leading to concentrated contact stresses and fluid film disruption.
Question 2002
Topic: 3. Adult Reconstruction (Hip & Knee)
During a posterior-stabilized total knee arthroplasty, the surgeon notes that the knee is tight in flexion but perfectly balanced in extension. Which of the following is the most appropriate next step to balance the knee?
Correct Answer & Explanation
. Downsize the femoral component
Explanation
A knee that is tight in flexion and balanced in extension requires an increase in the flexion gap without altering the extension gap. Downsizing the femoral component achieves this by reducing the posterior condylar offset.
Question 2003
Topic: 3. Adult Reconstruction (Hip & Knee)
A 65-year-old male presents with severe acute left hip pain 3 weeks after a primary total hip arthroplasty. Aspiration yields 35,000 WBCs/uL (92% PMNs). The implant is radiographically well-fixed. What is the most appropriate next step in management?
Correct Answer & Explanation
. Debridement, antibiotics, and implant retention (DAIR) with modular exchange
Explanation
In the setting of an acute early periprosthetic joint infection (<4 weeks post-op) with well-fixed components and a known or highly suspected organism, DAIR with modular component exchange is the standard of care.
Question 2004
Topic: 3. Adult Reconstruction (Hip & Knee)
A 68-year-old female complains of a painful 'catching' sensation in her knee when extending from a flexed position, one year following a posterior-stabilized total knee arthroplasty. What is the most likely etiology?
Correct Answer & Explanation
. Fibrous nodule formation at the superior pole of the patella engaging the intercondylar box
Explanation
Patellar clunk syndrome occurs primarily in posterior-stabilized TKA designs when a fibrous nodule forms at the superior pole of the patella and catches in the intercondylar box of the femoral component during active extension.
Question 2005
Topic: 3. Adult Reconstruction (Hip & Knee)
During a posterior-stabilized total knee arthroplasty, trial reduction demonstrates the knee is balanced in extension but significantly tight in flexion. Which of the following maneuvers is the most appropriate next step?
Correct Answer & Explanation
. Downsize the femoral component and re-cut the posterior condyles
Explanation
A knee that is tight in flexion and balanced in extension requires increasing the flexion gap without altering the extension gap. Downsizing the femoral component using a posterior referencing system decreases the posterior condylar offset, thereby increasing the flexion gap.
Question 2006
Topic: Total Knee Arthroplasty (TKA)
A 65-year-old female complains of giving way and recurrent effusions 2 years after a primary TKA. Examination reveals symmetrical extension gap stability, but instability to varus and valgus stress at 90 degrees of flexion. Which intraoperative error most likely caused this presentation?
Correct Answer & Explanation
. Undersizing the femoral component
Explanation
Undersizing the femoral component (specifically the anteroposterior dimension) increases the flexion gap without affecting the extension gap. This mismatch leads to isolated flexion instability.
Question 2007
Topic: Total Hip Arthroplasty (THA)
A 55-year-old male with a ceramic-on-ceramic total hip arthroplasty presents with a high-pitched squeaking sound during hip flexion. Which of the following factors is most strongly associated with this phenomenon?
Correct Answer & Explanation
. Edge loading due to component malposition
Explanation
Squeaking in ceramic-on-ceramic THA is predominantly associated with edge loading. This often results from acetabular cup malposition, such as excessive steepness or anteversion, which leads to stripe wear and microseparation.
Question 2008
Topic: Total Knee Arthroplasty (TKA)
A patient presents with a painful popping sensation at the superior pole of the patella when extending the knee from 45 degrees to full extension, 1 year after a posterior-stabilized TKA. What is the most appropriate management?
Correct Answer & Explanation
. Arthroscopic excision of the fibrotic nodule
Explanation
This is the classic presentation of patellar clunk syndrome, caused by a fibrotic nodule forming at the superior pole of the patella that catches in the intercondylar box of a posterior-stabilized femur. Arthroscopic excision of the nodule provides excellent results.
Question 2009
Topic: 3. Adult Reconstruction (Hip & Knee)
In the workup of a suspected periprosthetic joint infection (PJI), a synovial fluid alpha-defensin test is ordered. What is the primary physiological role of alpha-defensin in this context?
Correct Answer & Explanation
. It is an antimicrobial peptide released by neutrophils.
Explanation
Alpha-defensin is an antimicrobial peptide released by host neutrophils in response to pathogens. Its measurement in synovial fluid is a highly specific and sensitive biomarker for diagnosing periprosthetic joint infection.
Question 2010
Topic: 3. Adult Reconstruction (Hip & Knee)
A 62-year-old male with a metal-on-polyethylene total hip arthroplasty presents with groin pain and a large cystic mass 5 years postoperatively. Blood tests show elevated cobalt levels but normal chromium levels. What is the most likely etiology of his symptoms?
Correct Answer & Explanation
. Corrosion at the modular head-neck junction (trunnionosis)
Explanation
Mechanically assisted crevice corrosion at the modular head-neck junction (trunnionosis) typically presents with an adverse local tissue reaction. It is characterized by elevated serum cobalt levels out of proportion to chromium levels.
Question 2011
Topic: Total Hip Arthroplasty (THA)
During a revision THA, the surgeon notes massive acetabular bone loss with superior migration of the hip center by 4 cm, but the teardrop and Kohler's line remain intact. According to the Paprosky classification, what type of defect is this, and what is the preferred management?
Correct Answer & Explanation
. Paprosky 3A; hemispherical cup with structural allograft or metal augment
Explanation
A Paprosky 3A defect is characterized by greater than 3 cm of superior migration with intact medial wall structures (Kohler's line). Management typically involves a hemispherical cup supplemented with structural allograft or highly porous metal augments to address the superior defect.
Question 2012
Topic: 3. Adult Reconstruction (Hip & Knee)
When performing a total elbow arthroplasty (TEA) for a patient with severe advanced rheumatoid arthritis, what is the primary biomechanical advantage of using a linked (semi-constrained) implant over an unlinked implant?
Correct Answer & Explanation
. It compensates for severe ligamentous insufficiency and profound bone loss
Explanation
Linked (semi-constrained) TEA implants do not rely on native capsuloligamentous structures for stability. This makes them the implant of choice for patients with profound ligamentous instability, severe bone loss, or extensive deformity, all of which are common in end-stage rheumatoid arthritis or post-traumatic scenarios. Unlinked implants require intact collateral ligaments and adequate bone stock for stability.
Question 2013
Topic: 3. Adult Reconstruction (Hip & Knee)
A 75-year-old male is undergoing a total elbow arthroplasty (TEA) for a severely comminuted distal humerus fracture. The surgeon elects to use a triceps-sparing (triceps-on) approach. Compared to the classic triceps-reflecting (Bryan-Morrey) approach, the triceps-sparing approach has a significantly lower risk of which specific complication?
Correct Answer & Explanation
. Triceps insufficiency and avulsion
Explanation
Triceps-sparing approaches (such as the paratricipital or triceps-split approach) leave the extensor mechanism attached to the olecranon. This drastically reduces the risk of postoperative triceps insufficiency, weakness, or avulsion compared to approaches that require detachment and subsequent repair of the triceps tendon (like the Bryan-Morrey reflecting approach or the olecranon osteotomy).
Question 2014
Topic: 3. Adult Reconstruction (Hip & Knee)
A 45-year-old male manual laborer with severe, painful post-traumatic osteoarthritis of his right dominant elbow requests a total elbow arthroplasty (TEA) to return to heavy lifting work. Which of the following represents the most significant contraindication to performing a TEA in this patient?
Correct Answer & Explanation
. His requirement to frequently lift objects heavier than 5-10 lbs
Explanation
A strict, permanent lifting restriction of 5 to 10 pounds is generally required following TEA to prevent aseptic loosening and mechanical failure. Therefore, TEA is absolutely contraindicated in young patients expecting to perform heavy manual labor.
Question 2015
Topic: 3. Adult Reconstruction (Hip & Knee)
An 82-year-old female with severe osteoporosis sustains a comminuted, intra-articular distal humerus fracture (AO/OTA 13-C3). Which of the following is an established advantage of primary total elbow arthroplasty (TEA) compared to open reduction and internal fixation (ORIF) in this patient?
Correct Answer & Explanation
. More rapid postoperative mobilization and predictable early functional recovery
Explanation
In elderly patients with poor bone stock, primary TEA provides reliable, rapid return to function and avoids the high short-term complication rates of ORIF, such as nonunion or hardware failure. However, TEA imposes lifetime lifting restrictions and carries a higher long-term risk of aseptic loosening.
Question 2016
Topic: 3. Adult Reconstruction (Hip & Knee)
Which of the following is the most common cause of late failure requiring revision in anatomic total shoulder arthroplasty (aTSA)?
Correct Answer & Explanation
. Glenoid component aseptic loosening
Explanation
Aseptic loosening of the glenoid component is the most frequent cause of late failure and revision following aTSA. Contributing factors include eccentric loading from unaddressed posterior subluxation and particulate wear debris.
Question 2017
Topic: 3. Adult Reconstruction (Hip & Knee)
A 60-year-old patient with post-traumatic elbow arthritis is being considered for an unlinked total elbow arthroplasty (TEA). Which of the following is an absolute contraindication for using an unlinked implant?
Correct Answer & Explanation
. Severe ligamentous insufficiency or gross instability
Explanation
Unlinked TEA implants rely heavily on the native soft-tissue envelope, specifically the collateral ligaments and joint capsule, for stability. Therefore, severe ligamentous insufficiency or gross instability is an absolute contraindication for an unlinked design.
Question 2018
Topic: 3. Adult Reconstruction (Hip & Knee)
An 82-year-old woman with severe osteoporosis presents with a comminuted, intra-articular distal humerus fracture (AO Type 13-C3). The surgeon decides to proceed with a Total Elbow Arthroplasty (TEA) rather than ORIF. According to the literature, which of the following is an expected comparative outcome of TEA versus ORIF for this specific patient population at 1 to 2 years postoperatively?
Correct Answer & Explanation
. TEA has superior functional range of motion but a higher lifetime complication and reoperation rate.
Explanation
In elderly patients with severe osteoporotic comminuted distal humerus fractures, TEA is often favored over ORIF because it allows immediate postoperative mobilization and provides better, more predictable functional scores and range of motion at 1-2 years. However, TEA is associated with a permanent lifting restriction (typically <5-10 lbs) and higher lifetime complication and reoperation rates (e.g., aseptic loosening, bushing wear, periprosthetic fracture).
Question 2019
Topic: 3. Adult Reconstruction (Hip & Knee)
A 28-year-old male sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III) after a fall from a height. Which of the following fixation constructs provides the most biomechanical stability for this specific fracture pattern?
Correct Answer & Explanation
. Dynamic hip screw with a derotational screw
Explanation
Pauwels type III femoral neck fractures have a vertical orientation and high shear forces. A fixed-angle device, such as a sliding hip screw, provides superior biomechanical stability compared to parallel cancellous screws alone in these high-shear patterns.
Question 2020
Topic: 3. Adult Reconstruction (Hip & Knee)
During a posterior-stabilized (PS) total knee arthroplasty, trial reduction reveals the knee is symmetric and balanced in extension, but symmetrically tight in deep flexion. Which of the following is the most appropriate surgical adjustment to achieve a balanced knee?
Correct Answer & Explanation
. Decrease the anteroposterior (AP) dimension of the femoral component
Explanation
Symmetrical tightness in flexion with a balanced extension gap implies that the flexion gap is too small. Decreasing the anteroposterior (AP) dimension of the femoral component (downsizing the femur using anterior referencing) reduces the posterior condylar offset, thereby opening up the flexion gap without altering the extension gap. Recutting the distal femur or releasing the posterior capsule would primarily affect the extension gap, while downsizing the polyethylene insert would increase both the flexion and extension gaps.
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