Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 95 of 326

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 1881

Topic: 3. Adult Reconstruction (Hip & Knee)

Increasing the femoral head size from 28 mm to 36 mm in a total hip arthroplasty has which of the following biomechanical effects?

. Decreases the head-to-neck ratio
. Increases volumetric polyethylene wear
. Decreases the jump distance
. Increases the risk of impingement prior to dislocation
. Decreases the range of motion

Correct Answer & Explanation

. Increases volumetric polyethylene wear

Explanation

A larger femoral head size increases the jump distance and the head-to-neck ratio, improving range of motion and joint stability. However, it increases the sliding distance per step, leading to higher volumetric polyethylene wear.

Question 1882

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with severe hip pain and fever 2 weeks after a primary THA. Aspiration yields purulent fluid. Debridement, antibiotics, and implant retention (DAIR) is planned. Which intraoperative step is mandatory to maximize success?

. Exchange of the modular femoral head and acetabular liner
. Revision of the femoral stem only
. Use of a constrained acetabular liner
. Retention of all original components to avoid destabilization
. Administration of intra-articular vancomycin powder only

Correct Answer & Explanation

. Exchange of the modular femoral head and acetabular liner

Explanation

During a DAIR procedure for acute periprosthetic joint infection, exchanging all modular components (head and liner) is critical to access the entire joint space, debride necrotic tissue, and physically reduce the biofilm burden.

Question 1883

Topic: 3. Adult Reconstruction (Hip & Knee)

A 32-year-old patient on chronic corticosteroids develops Ficat Stage II avascular necrosis of the femoral head. There is no subchondral collapse on plain radiographs, but MRI shows necrosis involving 40% of the weight-bearing area. Which treatment is most indicated?

. Total hip arthroplasty
. Core decompression with or without bone grafting
. Non-weight bearing with crutches for 6 months
. Resurfacing arthroplasty
. Proximal femoral osteotomy

Correct Answer & Explanation

. Core decompression with or without bone grafting

Explanation

Ficat Stage II AVN (pre-collapse with reactive radiographic changes) is the classic indication for head-preserving procedures like core decompression. This reduces intraosseous pressure and aims to stimulate revascularization.

Question 1884

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old male sustains a posterior hip dislocation with an associated Pipkin Type II femoral head fracture. After closed reduction, CT confirms a displaced, large superior head fragment. What is the most appropriate surgical management?

. Fragment excision via a posterior approach
. ORIF via a Smith-Petersen (anterior) approach
. Nonoperative management with skeletal traction
. Total hip arthroplasty
. Excision and partial hip resurfacing

Correct Answer & Explanation

. ORIF via a Smith-Petersen (anterior) approach

Explanation

Pipkin Type II fractures involve the weight-bearing dome cephalad to the fovea. Displaced fragments require ORIF. An anterior approach (Smith-Petersen) or surgical dislocation provides optimal visualization of the superior femoral head for anatomic fixation.

Question 1885

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male with a history of a metal-on-polyethylene total hip arthroplasty utilizing a large-diameter modular cobalt-chromium femoral head presents with groin pain and swelling. Aspiration yields sterile fluid. Laboratory tests reveal significantly elevated serum cobalt levels with normal chromium levels. MRI demonstrates a solid and cystic soft-tissue mass around the hip. What is the most likely pathophysiologic mechanism for this presentation?

. Type IV hypersensitivity reaction to polyethylene debris
. Mechanically assisted crevice corrosion at the head-neck junction
. Third-body wear from retained cement debris
. Edge loading due to excessive acetabular cup anteversion
. Galvanic corrosion at the stem-cement interface

Correct Answer & Explanation

. Mechanically assisted crevice corrosion at the head-neck junction

Explanation

The differential elevation of cobalt over chromium in a metal-on-polyethylene THA indicates mechanically assisted crevice corrosion (trunnionosis) at the modular head-neck junction. This leads to an adverse local tissue reaction (ALTR) or pseudotumor.

Question 1886

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old female presents with complaints of instability and knee effusion 6 months after a posterior-stabilized total knee arthroplasty (TKA). Examination reveals a stable knee in full extension and 90 degrees of flexion, but marked laxity at 30 to 45 degrees of flexion. What is the most likely intraoperative technical error that caused this presentation?

. Undersizing the femoral component
. Excessive proximal tibial resection
. Joint line elevation
. Asymmetric posterior condylar resection
. Failure to release the medial collateral ligament

Correct Answer & Explanation

. Joint line elevation

Explanation

Mid-flexion instability in TKA is classically caused by joint line elevation. This occurs when excessive distal femoral resection is compensated by inserting a thicker polyethylene insert, which balances extension but leaves the mid-flexion arc loose.

Question 1887

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male undergoes a total hip arthroplasty utilizing a ceramic-on-ceramic bearing surface. Two years postoperatively, he complains of a loud squeaking noise from the hip during specific movements. What is the most significant risk factor for this complication?

. Excessive femoral stem retroversion
. Acetabular component malposition leading to edge loading
. Utilizing an oversized femoral head (> 36mm)
. Impingement of the iliopsoas tendon over the anterior brim
. Trunnionosis at the head-neck taper

Correct Answer & Explanation

. Acetabular component malposition leading to edge loading

Explanation

Squeaking in ceramic-on-ceramic total hip arthroplasties is strongly associated with edge loading of the bearing surfaces. This most commonly results from acetabular component malposition, specifically excessive cup anteversion or vertical inclination.

Question 1888

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old male is diagnosed with Ficat Stage II avascular necrosis of the femoral head. If non-operative management fails, preserving the native joint is dependent on the viability of the femoral head's blood supply. What is the primary arterial supply to the weight-bearing dome of the adult femoral head?

. Artery of the ligamentum teres
. Superior gluteal artery
. Inferior gluteal artery
. Deep branch of the medial femoral circumflex artery
. Descending branch of the lateral femoral circumflex artery

Correct Answer & Explanation

. Deep branch of the medial femoral circumflex artery

Explanation

The primary blood supply to the adult femoral head originates from the medial femoral circumflex artery (MFCA). Specifically, the deep branch of the MFCA supplies the superior, weight-bearing dome via the lateral epiphyseal arteries.

Question 1889

Topic: 3. Adult Reconstruction (Hip & Knee)

An 80-year-old female falls and sustains a periprosthetic femur fracture around a cemented total hip arthroplasty stem. Radiographs demonstrate a fracture at the tip of the stem. The stem is radiographically loose, but there is excellent surrounding proximal bone stock. How is this fracture classified, and what is the standard treatment?

. Vancouver B1; treated with ORIF using a locking plate and cables
. Vancouver B2; treated with revision to a long cementless diaphyseal-engaging stem
. Vancouver B3; treated with a proximal femoral replacement
. Vancouver C; treated with ORIF below the tip of the stem
. Vancouver A; treated with non-operative protected weight-bearing

Correct Answer & Explanation

. Vancouver B2; treated with revision to a long cementless diaphyseal-engaging stem

Explanation

This is a Vancouver B2 fracture, characterized by a fracture around a loose stem in the presence of adequate bone stock. The standard of care is revision arthroplasty using a long cementless stem that bypasses the fracture site to achieve stable diaphyseal fixation.

Question 1890

Topic: 3. Adult Reconstruction (Hip & Knee)

During a posterior-stabilized total knee arthroplasty, the surgeon notes that the knee is well-balanced in extension but is overly tight in flexion. Which of the following is the most appropriate step to balance the knee?

. Recut the distal femur
. Decrease the posterior tibial slope
. Downsize the femoral component
. Release the posterior capsule
. Release the superficial medial collateral ligament

Correct Answer & Explanation

. Downsize the femoral component

Explanation

A knee that is tight in flexion but balanced in extension has a tight flexion gap. Downsizing the femoral component or increasing the posterior tibial slope will increase the flexion gap without altering the extension gap.

Question 1891

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old man with a metal-on-metal total hip arthroplasty presents with groin pain and a palpable anterior mass. Aspiration yields thick, sterile fluid. What is the most likely histologic finding of the periarticular tissue?

. Extensive neutrophil infiltration
. Perivascular lymphocytic infiltration
. Birefringent crystals under polarized light
. Granulomatous inflammation with caseating necrosis
. Giant cells with polymethylmethacrylate debris

Correct Answer & Explanation

. Perivascular lymphocytic infiltration

Explanation

Adverse local tissue reaction (ALTR) or metallosis from metal-on-metal bearings is characterized histologically by an Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesion (ALVAL), showing perivascular lymphocytic infiltration.

Question 1892

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old woman presents with acute onset of knee pain and swelling 3 weeks after a primary total knee arthroplasty. Aspiration reveals 65,000 WBCs/mcL with 95% neutrophils. What is the most appropriate surgical treatment?

. One-stage component revision
. Two-stage component revision with an antibiotic spacer
. Arthroscopic irrigation and debridement
. Open debridement, antibiotics, and implant retention (DAIR)
. Knee arthrodesis

Correct Answer & Explanation

. Open debridement, antibiotics, and implant retention (DAIR)

Explanation

In the setting of an acute early periprosthetic joint infection (less than 4 weeks post-op) with well-fixed components, Open Debridement, Antibiotics, and Implant Retention (DAIR) with polyethylene exchange is the standard of care.

Question 1893

Topic: 3. Adult Reconstruction (Hip & Knee)

During a medial parapatellar approach for a total knee arthroplasty, taking the arthrotomy too far distally and laterally risks injury to which of the following structures?

. Infrapatellar branch of the saphenous nerve
. Patellar tendon insertion
. Anterior tibial artery
. Common peroneal nerve
. Superficial medial collateral ligament

Correct Answer & Explanation

. Patellar tendon insertion

Explanation

Extending a medial parapatellar arthrotomy too distally and laterally on the tibial tubercle risks avulsing the patellar tendon insertion. The infrapatellar branch of the saphenous nerve is typically encountered more medially and is cut during the superficial approach.

Question 1894

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old woman presents with an audible and palpable "clunk" during active extension of her knee, 1 year after undergoing a posterior-stabilized total knee arthroplasty (TKA). What is the primary cause of this phenomenon?

. Avascular necrosis of the superior pole of the patella
. A fibrous nodule at the superior pole of the patella catching in the femoral box
. Internal malrotation of the tibial tray
. An oversized femoral component causing quadriceps overtensioning
. Subluxation of the popliteus tendon over the lateral epicondyle

Correct Answer & Explanation

. A fibrous nodule at the superior pole of the patella catching in the femoral box

Explanation

Patellar clunk syndrome occurs primarily in posterior-stabilized TKA designs when a fibrosynovial nodule forms at the superior pole of the patella. This nodule engages the intercondylar box in flexion and abruptly "clunks" out during active extension.

Question 1895

Topic: Total Hip Arthroplasty (THA)

A patient experiences recurrent posterior dislocations following a primary total hip arthroplasty. Radiographs and a CT scan demonstrate the acetabular component is well-fixed but placed in 5 degrees of retroversion. Which of the following is the most appropriate definitive management?

. Application of a hip abduction orthosis for 6 weeks
. Cementing a constrained liner into the existing acetabular shell
. Revision of the acetabular component to increase anteversion
. Revision of the femoral component to increase femoral offset
. Advancement of the greater trochanter to increase abductor tension

Correct Answer & Explanation

. Revision of the acetabular component to increase anteversion

Explanation

Recurrent posterior instability driven by acetabular retroversion requires correction of the underlying mechanical malposition. Revision of the well-fixed but malpositioned acetabular shell to appropriate anteversion is the definitive treatment.

Question 1896

Topic: 3. Adult Reconstruction (Hip & Knee)

An 82-year-old female presents with a displaced periprosthetic distal femur fracture (Lewis and Rorabeck Type II) above a well-fixed total knee arthroplasty. Review of operative records confirms the femoral component has a closed intercondylar box design. What is the most appropriate surgical management?

. Retrograde intramedullary nailing
. Revision to a distal femoral replacement endoprosthesis
. Open reduction and internal fixation with a lateral locking plate
. Skeletal traction for 6 weeks followed by functional bracing
. Application of a circular fine-wire external fixator

Correct Answer & Explanation

. Open reduction and internal fixation with a lateral locking plate

Explanation

The fracture is above a well-fixed TKA (Type II), meaning revision arthroplasty is unnecessary. Because the TKA has a closed intercondylar box, retrograde nailing is contraindicated, making lateral locked plating the gold standard.

Question 1897

Topic: 3. Adult Reconstruction (Hip & Knee)
A 28-year-old female involved in a motor vehicle collision sustains a Hawkins Type III talar neck fracture. Which blood supply is most commonly disrupted, leading to the high risk of avascular necrosis (AVN) in the talar body?
. Artery of the tarsal canal
. Dorsalis pedis artery
. Deltoid branches of the posterior tibial artery
. Peroneal artery
. Artery of the sinus tarsi

Correct Answer & Explanation

. Artery of the tarsal canal

Explanation

The artery of the tarsal canal, a branch of the posterior tibial artery, provides the dominant blood supply to the talar body. Disruption of this artery in displaced talar neck fractures (Hawkins II-IV) is the primary cause of avascular necrosis.

Question 1898

Topic: 3. Adult Reconstruction (Hip & Knee)
Figure 53a shows the AP radiograph of a 70-year-old patient who is scheduled to undergo unicompartmental knee arthroplasty. Figure 53b shows the immediate postoperative radiograph, and the radiograph shown in Figure 53c, obtained 6 months after surgery, shows a medial tibial plateau fracture. The etiology of the fracture is best related to
. marked osteoporosis.
. reduced contact area of a unicompartmental knee arthroplasty for load transmission.
. excessive medial placement of the tibial component of the unicompartmental knee arthroplasty.
. multiple drill holes that violate the medial cortex.
. osteonecrosis of the medial tibial plateau.

Correct Answer & Explanation

. multiple drill holes that violate the medial cortex.

Explanation

While all of the above may contribute to the etiology of a tibial plateau fracture following unicompartmental knee arthroplasty, the recent literature has clearly noted that pin placement for fixation of tibial resection guides is the most critical factor associated with a tibial plateau fracture following unicompartmental knee arthroplasty. Vince and Cyran suggest that fractures associated with unicompartmental knee arthroplasty might be avoidable by limiting the number and paying attention to the location of the pin holes that are created to secure the tibial resection guides. Brumby and associates suggest avoiding multiple guide pin holes in the proximal tibia for unicompartmental knee arthroplasty. They currently recommend the use of one centrally placed pin and an ankle clamp to stabilize the resection guide. Yang and associates note that a medial tibial plateau fracture in association with minimally invasive unicompartmental knee arthroplasty can be eliminated by avoiding fixation pins close to the medial tibial cortex.

Question 1899

Topic: 3. Adult Reconstruction (Hip & Knee)

You are evaluating a 70-year-old male for a suspected periprosthetic joint infection (PJI) 3 years after a total knee arthroplasty. A synovial fluid sample is sent for alpha-defensin testing. What is the biological origin and function of alpha-defensin in the context of a joint infection?

. An acute-phase reactant produced by the liver in response to systemic inflammation
. A biomarker of synovial cell apoptosis induced by bacterial toxins
. An antimicrobial peptide released by neutrophils in response to pathogens
. A byproduct of bacterial membrane degradation
. A cytokine in the Interleukin-6 pathway secreted by macrophages

Correct Answer & Explanation

. An antimicrobial peptide released by neutrophils in response to pathogens

Explanation

Alpha-defensin is a highly specific antimicrobial peptide naturally released by activated human neutrophils in the presence of pathogens. It integrates into and destroys bacterial cell membranes. Its presence in synovial fluid is a highly accurate biomarker for periprosthetic joint infection, as it distinguishes between aseptic inflammation and true bacterial infection.

Question 1900

Topic: 3. Adult Reconstruction (Hip & Knee)

Based on the recommendations of the International Consensus Meeting (ICM) on Musculoskeletal Infection, which of the following is considered an absolute contraindication to a single-stage (one-stage) exchange arthroplasty for a periprosthetic joint infection?

. Symptom duration of 3 weeks
. Elevated ESR and CRP
. Unknown infecting microorganism preoperatively
. Patient age greater than 75 years
. Infection with Methicillin-sensitive Staphylococcus aureus (MSSA)

Correct Answer & Explanation

. Unknown infecting microorganism preoperatively

Explanation

A single-stage exchange requires specific conditions for success, primarily the ability to deliver targeted, effective local and systemic antibiotics. An absolute contraindication to single-stage exchange is an unknown infecting organism preoperatively, because the surgeon cannot appropriately mix targeted antibiotics into the bone cement. Other contraindications include systemic sepsis, severe soft tissue compromise, and highly virulent organisms without available oral antibiotic suppression.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page