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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 100 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 1981

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the 2018 International Consensus Meeting (ICM) criteria for the diagnosis of Periprosthetic Joint Infection (PJI), which of the following is considered a 'major criterion' that is diagnostic of PJI on its own?

. Elevated serum C-reactive protein (CRP) > 10 mg/L
. Elevated synovial fluid white blood cell (WBC) count > 3,000 cells/uL
. A single positive intraoperative tissue culture for Staphylococcus epidermidis
. A sinus tract communicating with the prosthesis
. Positive leukocyte esterase on a synovial fluid dipstick

Correct Answer & Explanation

. A sinus tract communicating with the prosthesis

Explanation

Under the ICM criteria, there are two major criteria for PJI, either of which is definitively diagnostic on its own: 1) A sinus tract communicating with the prosthesis, or 2) Two positive periprosthetic cultures with phenotypically identical organisms. The other options are minor criteria that contribute to an aggregate score.

Question 1982

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male with a ceramic-on-ceramic total hip arthroplasty complains of a loud squeaking noise from his hip during certain phases of his gait cycle. He has no pain, and radiographs show well-fixed components. What is the most common biomechanical etiology of this squeaking phenomenon?

. Third-body wear from retained acrylic bone cement
. Edge loading secondary to cup malposition (e.g., steep inclination)
. Galvanic corrosion at the modular head-neck taper
. Insufficient femoral offset leading to soft tissue laxity
. Subclinical periprosthetic joint infection

Correct Answer & Explanation

. Edge loading secondary to cup malposition (e.g., steep inclination)

Explanation

Squeaking in ceramic-on-ceramic THA is fundamentally a problem of fluid-film lubrication failure. The most common biomechanical cause is edge loading, which typically occurs due to component malposition, such as excessive acetabular cup inclination (a 'steep' cup) or malversion. This causes stripe wear on the ceramic head and loss of lubrication.

Question 1983

Topic: 3. Adult Reconstruction (Hip & Knee)

During the gap balancing phase of a primary total knee arthroplasty, the surgeon utilizes tensioning devices and finds that the knee is perfectly balanced in extension, but the flexion gap is excessively tight. Assuming correct soft tissue tensioning, which of the following bony maneuvers is most appropriate to specifically increase the flexion gap without altering the extension gap?

. Recut the distal femur to remove 2 mm more of bone
. Upsize the femoral component using an anterior referencing guide
. Decrease the posterior slope of the tibial cut
. Downsize the femoral component (anterior referencing) or increase the posterior tibial slope
. Perform a more extensive release of the posterior capsule

Correct Answer & Explanation

. Downsize the femoral component (anterior referencing) or increase the posterior tibial slope

Explanation

A tight flexion gap with a balanced extension gap means more space is needed only in flexion. Options to selectively increase the flexion gap include downsizing the femoral component (which removes more posterior condylar bone when using anterior referencing) or increasing the posterior slope of the tibia (which primarily opens the gap in flexion).

Question 1984

Topic: 3. Adult Reconstruction (Hip & Knee)

An 81-year-old female presents with a Vancouver Type B3 periprosthetic hip fracture around a cemented stem implanted 15 years ago. Radiographs reveal a grossly loose stem and severe osteolysis with nearly complete loss of the proximal medial calcar and lateral cortex. What is the most appropriate surgical management?

. Open reduction and internal fixation with a lateral locking plate and cerclage cables
. Open reduction and internal fixation with a lateral plate and cortical strut allograft
. Revision to a long, fully porous-coated cylindrical stem without structural grafting
. Proximal femoral replacement (megaprosthesis)
. Resection arthroplasty (Girdlestone procedure)

Correct Answer & Explanation

. Proximal femoral replacement (megaprosthesis)

Explanation

Vancouver B3 fractures involve a loose implant and inadequate proximal bone stock. In an elderly, low-demand patient, proximal femoral replacement provides immediate stability, bypasses the poor bone stock, and allows for early weight-bearing.

Question 1985

Topic: 3. Adult Reconstruction (Hip & Knee)

During open reduction and internal fixation of a displaced patella fracture, meticulous soft tissue handling is required to prevent avascular necrosis of the proximal pole. Where does the predominant extraosseous arterial supply enter the patella?

. Superior pole
. Inferior pole
. Directly posterior through the articular cartilage
. Medial facet exclusively
. Lateral facet exclusively

Correct Answer & Explanation

. Inferior pole

Explanation

The predominant blood supply to the patella enters through the inferior pole via an anastomotic ring. Consequently, displaced fractures or excessive surgical dissection near the inferior pole place the proximal pole at high risk for avascular necrosis.

Question 1986

Topic: 3. Adult Reconstruction (Hip & Knee)
A 72-year-old woman with rheumatoid arthritis who underwent primary total knee arthroplasty 2 years ago has had diffuse knee pain that developed shortly after the surgery. The patient has difficulty with stair descent and arising from chairs. Evaluation for infection is negative. AP and lateral radiographs are shown in Figure 26. Management should now consist of:
. anti-inflammatory drugs.
. a knee brace.
. physical therapy for quadriceps strengthening.
. revision to a thicker polyethylene insert.
. revision to a posterior stabilized implant.

Correct Answer & Explanation

. revision to a posterior stabilized implant.

Explanation

The radiographs show posterior flexion instability that is the result of flexion-extension gap imbalance and/or posterior cruciate ligament incompetence after a posterior cruciate-retaining total knee arthroplasty. The radiographs also show anterior femoral displacement on the tibia. Pagnano and associates reported on a series of patients with painful total knee arthroplasties who had been previously diagnosed as having pain of unknown etiology, showing that the pain was secondary to flexion instability. Pain relief was achieved by revision to a posterior stabilized implant.

Question 1987

Topic: 3. Adult Reconstruction (Hip & Knee)
Figures below show the radiographs obtained from a 90-year-old woman who is seen in the emergency department after a fall from a height. She has right hip and thigh pain and is unable to bear weight. Based on this patient's history and imaging, what is the best next step?
. Hip revision and implantation of a proximal femoral replacement
. Hip revision and implantation of a tapered fluted stem
. Open reduction and internal fixation with a locked plate and allograft struts
. Erythrocyte sedimentation rate and C-reactive protein laboratory studies

Correct Answer & Explanation

. Erythrocyte sedimentation rate and C-reactive protein laboratory studies

Explanation

Periprosthetic fracture is the third most common reason (after loosening and infection) for revision surgery after total hip arthroplasty (THA). Late periprosthetic fracture risk is 0.4% to 1.1% after primary THA and 2.1% to 4% after revision THA. Risk factors for periprosthetic fracture include age over 70 years, decreasing bone mass, and loosening of implants and osteolysis. The risk of concomitant infection in the presence of a periprosthetic fracture is 11%, according to Chevillotte and associates. Obtaining presurgical aspiration or intrasurgical tissue for culture is recommended if concomitant infection is suspected.

Question 1988

Topic: 3. Adult Reconstruction (Hip & Knee)
A 30-year-old man sustains a high-energy Pauwels Type III femoral neck fracture. What is the optimal surgical construct to minimize the risk of varus collapse and non-union in this specific fracture pattern?
. Three cannulated screws in an inverted triangle
. A fixed-angle device such as a sliding hip screw
. Hemiarthroplasty
. Total hip arthroplasty
. Two parallel cannulated screws

Correct Answer & Explanation

. A fixed-angle device such as a sliding hip screw

Explanation

Pauwels Type III fractures (>50 degrees vertical angle) are highly unstable due to significant shear forces. A fixed-angle device, such as a sliding hip screw (often supplemented with a derotation screw) or a cephalomedullary nail, provides superior biomechanical stability compared to multiple cannulated screws.

Question 1989

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the 2018 International Consensus Meeting (ICM) criteria for periprosthetic joint infection (PJI), which of the following represents a definitive (major) criterion for the diagnosis of PJI?

. A single positive tissue culture for Staphylococcus epidermidis
. Elevated serum CRP (>10 mg/L) and D-dimer (>860 ng/mL)
. Presence of a sinus tract communicating with the joint
. Synovial fluid WBC count of 3,500 cells/uL
. Positive leukocyte esterase test on synovial fluid

Correct Answer & Explanation

. Presence of a sinus tract communicating with the joint

Explanation

According to the 2018 ICM criteria, the two major criteria (either of which is definitive for the diagnosis of PJI) are: 1) Two positive periprosthetic cultures with phenotypically identical organisms, or 2) A sinus tract communicating with the joint. The other options represent minor criteria or diagnostic biomarkers that contribute to an aggregate score but are not definitively diagnostic on their own.

Question 1990

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary posterior-stabilized total knee arthroplasty utilizing a measured resection technique, the surgeon evaluates the gaps. The extension gap is symmetric and perfectly balanced. However, the flexion gap is tight medially and loose laterally. What is the most appropriate corrective action?

. Recut the proximal tibia with more varus
. Externally rotate the femoral component
. Release the deep medial collateral ligament
. Downsize the femoral component
. Increase the posterior slope of the tibial cut

Correct Answer & Explanation

. Externally rotate the femoral component

Explanation

A flexion gap that is tight medially and loose laterally signifies internal rotation of the femoral component relative to the surgical epicondylar axis. Externally rotating the femoral component will decrease the medial posterior condyle thickness (thereby opening the medial flexion gap) and increase the lateral posterior condyle thickness (tightening the lateral flexion gap) without affecting the extension gap.

Question 1991

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old male undergoes a total hip arthroplasty using a ceramic-on-ceramic bearing. Which of the following is a recognized complication specifically associated with this bearing surface compared to standard metal-on-polyethylene?

. Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)
. Trunnionosis
. Squeaking
. Increased risk of volumetric wear
. Osteolysis induced by submicron polyethylene debris

Correct Answer & Explanation

. Squeaking

Explanation

Squeaking is a well-documented complication specific to ceramic-on-ceramic (CoC) bearings, occurring in up to 10% of patients. It is associated with microseparation, edge loading, and certain patient or implant characteristics. ALVAL is seen in metal-on-metal bearings. Volumetric wear and debris-induced osteolysis are classic complications of metal-on-polyethylene bearings.

Question 1992

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old female presents with a painful, swollen, and stiff knee 2 years after a primary TKA. Comprehensive infection workup is negative. She notes a history of severe contact dermatitis to cheap jewelry, and patch testing confirms a profound nickel allergy. If revision arthroplasty is pursued, which femoral component material is the most appropriate choice?

. Cobalt-chromium-molybdenum alloy
. Titanium-aluminum-vanadium alloy
. Oxidized zirconium
. Stainless steel
. Highly cross-linked polyethylene

Correct Answer & Explanation

. Oxidized zirconium

Explanation

In patients with symptomatic, documented metal hypersensitivity (most commonly nickel, cobalt, or chromium) who require knee arthroplasty or revision, standard cobalt-chromium components (which contain nickel) should be avoided. Oxidized zirconium (Oxinium) or pure titanium components lack nickel and are the implants of choice to avoid hypersensitivity reactions.

Question 1993

Topic: Total Hip Arthroplasty (THA)

When comparing the direct anterior approach to the posterior approach for primary total hip arthroplasty, the direct anterior approach is associated with a higher risk of iatrogenic injury to which of the following nerves?

. Sciatic nerve
. Superior gluteal nerve
. Lateral femoral cutaneous nerve
. Femoral nerve
. Inferior gluteal nerve

Correct Answer & Explanation

. Lateral femoral cutaneous nerve

Explanation

The direct anterior approach utilizes the internervous plane between the sartorius (femoral nerve) and the tensor fasciae latae (superior gluteal nerve). The lateral femoral cutaneous nerve crosses the surgical field anteriorly and is at the highest risk for neuropraxia or transection during this approach.

Question 1994

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old female sustains recurrent posterior dislocations following a right total hip arthroplasty via a posterior approach. CT scan demonstrates the acetabular cup is placed in 45 degrees of abduction and 5 degrees of retroversion. The femoral stem has 15 degrees of anteversion. What is the most likely cause of her posterior instability?

. Excessive combined anteversion
. Acetabular component retroversion
. Femoral component retroversion
. Insufficient acetabular abduction
. Excessive acetabular abduction

Correct Answer & Explanation

. Acetabular component retroversion

Explanation

The acetabular component should typically be placed in 15-20 degrees of anteversion and 40-45 degrees of abduction (the Lewinnek safe zone). This patient's cup is placed in 5 degrees of retroversion, which severely predisposes her to posterior dislocation, particularly with hip flexion and internal rotation. The combined anteversion is only 10 degrees (15 femoral + (-5) acetabular), which is below the ideal 25-40 degrees.

Question 1995

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with vague shoulder pain 18 months after a primary reverse total shoulder arthroplasty. Inflammatory markers are minimally elevated. A joint aspirate is obtained and grows Cutibacterium (formerly Propionibacterium) acnes after 10 days of incubation. Which of the following characteristics best describes this organism?

. Gram-negative aerobic bacillus
. Gram-positive anaerobic bacillus
. Gram-positive aerobic coccus
. Gram-negative anaerobic coccus
. Atypical fungal pathogen

Correct Answer & Explanation

. Gram-positive anaerobic bacillus

Explanation

Cutibacterium acnes is a slow-growing, Gram-positive, anaerobic (to aerotolerant) bacillus that resides as normal flora deep within the sebaceous glands of the skin, particularly around the shoulder. It is a notorious cause of indolent periprosthetic joint infections following shoulder arthroplasty and typically requires extended culture incubation (often up to 14 days) to be detected.

Question 1996

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old female presents with an audible and palpable 'pop' over the anterior aspect of her knee when rising from a chair. She underwent a posterior-stabilized total knee arthroplasty (TKA) one year ago. She is diagnosed with patellar clunk syndrome. At approximately which range of knee flexion does this phenomenon classically occur during active extension?

. 0 to 15 degrees
. 30 to 45 degrees
. 70 to 85 degrees
. 90 to 105 degrees
. 110 to 120 degrees

Correct Answer & Explanation

. 30 to 45 degrees

Explanation

Patellar clunk syndrome is a complication primarily seen in posterior-stabilized (PS) TKA designs. It occurs due to the formation of a fibrous nodule at the superior pole of the patella. As the knee actively extends from a flexed position, the nodule gets caught in the intercondylar box of the femoral component and then abruptly 'clunks' out of the box. This typically occurs between 30 to 45 degrees of flexion during active extension.

Question 1997

Topic: 3. Adult Reconstruction (Hip & Knee)

A patient is being evaluated for a suspected periprosthetic joint infection (PJI) following a total hip arthroplasty. The synovial fluid alpha-defensin immunoassay returns positive. What is the primary biological source of alpha-defensin in the synovial fluid?

. Macrophages
. T-lymphocytes
. Osteoblasts
. Synoviocytes
. Neutrophils

Correct Answer & Explanation

. Neutrophils

Explanation

Alpha-defensin is an antimicrobial peptide released predominantly by human neutrophils in response to the presence of pathogens. It has proven to be a highly sensitive and specific biomarker for diagnosing periprosthetic joint infections, as its levels rise dramatically in the presence of an active bacterial infection regardless of prior antibiotic use.

Question 1998

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male presents with groin pain and a palpable anterior hip mass 4 years after a total hip arthroplasty. Aspiration yields sterile, turbid fluid. MRI reveals a large cystic pseudotumor. Which combination of modular femoral head and stem characteristics places the patient at the highest risk for mechanically assisted crevice corrosion (trunnionosis)?

. Small diameter ceramic head on a Titanium alloy stem
. Large diameter Cobalt-Chromium head on a Titanium alloy stem
. Large diameter ceramic head on a Cobalt-Chromium stem
. Small diameter Cobalt-Chromium head on a Cobalt-Chromium stem
. Oxinium head on a stainless steel stem

Correct Answer & Explanation

. Large diameter Cobalt-Chromium head on a Titanium alloy stem

Explanation

Mechanically assisted crevice corrosion (MACC) at the modular head-neck junction (trunnionosis) is a recognized cause of adverse local tissue reaction (ALTR). The risk is significantly amplified by the use of large diameter (e.g., >36 mm) Cobalt-Chromium (CoCr) heads on Titanium (Ti) alloy stems with short, thin trunnions due to the increased frictional torque, micro-motion, and galvanic/fretting corrosion occurring at the mixed-metal interface.

Question 1999

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female with severe rheumatoid arthritis undergoes TKA for end-stage valgus osteoarthritis (Krackow Type II). Intraoperatively, after appropriate soft tissue balancing, the medial collateral ligament (MCL) is found to be completely attenuated and incompetent, resulting in gross coronal instability. Which implant constraint is definitively required?

. Cruciate-retaining (CR) bearing
. Posterior-stabilized (PS) bearing
. Constrained condylar knee (CCK) bearing
. Rotating hinge prosthesis
. Unicompartmental knee arthroplasty

Correct Answer & Explanation

. Rotating hinge prosthesis

Explanation

In the setting of total knee arthroplasty, coronal plane stability depends on collateral ligament competence. A constrained condylar knee (CCK) relies on the presence of functional collateral ligaments to prevent catastrophic post-failure. If the medial collateral ligament (MCL) is completely absent or incompetent, a CCK will fail, and a rotating hinge prosthesis is required to substitute for the absent collateral stability.

Question 2000

Topic: Total Hip Arthroplasty (THA)

A 40-year-old male with a ceramic-on-ceramic total hip arthroplasty complains of a highly audible 'squeaking' sound coming from his hip during ambulation. Radiographic evaluation of component positioning is most likely to reveal which of the following?

. Excessive retroversion and low inclination
. Excessive anteversion and high inclination
. Decreased femoral offset
. Excessive leg length
. Use of a 32 mm ceramic head instead of 36 mm

Correct Answer & Explanation

. Excessive anteversion and high inclination

Explanation

Squeaking in ceramic-on-ceramic THA is a phenomenon strongly linked to edge loading, stripe wear, and micro-separation. Edge loading occurs when the femoral head articulates against the rim of the acetabular liner rather than the dome. This is most strongly associated with component malpositioning, particularly when the acetabular cup is placed in excessive anteversion combined with excessive (steep) inclination.

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