Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 289 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 5761

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old woman with a history of a T10-to-pelvis posterior spinal fusion presents for a primary total hip arthroplasty (THA). Given her stiff spinopelvic articulation, which of the following adjustments to the acetabular component positioning is most appropriate to minimize the risk of dislocation?

. Decrease both anteversion and abduction
. Increase cup anteversion compared to standard positioning
. Decrease cup anteversion compared to standard positioning
. Position the cup in standard 40 degrees of abduction and 15 degrees of anteversion
. Utilize a larger femoral head with standard cup positioning only

Correct Answer & Explanation

. Increase cup anteversion compared to standard positioning

Explanation

Patients with a stiff spine cannot increase pelvic tilt (retrovert) during sitting, risking anterior impingement and posterior dislocation. Increasing the target acetabular anteversion helps compensate for this lack of dynamic pelvic mobility.

Question 5762

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old man undergoes revision THA for aseptic loosening. Preoperative planning involves placing screws into the acetabulum for supplementary cup fixation. According to Wasielewski's quadrant system, screw placement in the anterior-superior quadrant places which of the following structures at highest risk of injury?

. External iliac artery and vein
. Obturator nerve and vessels
. Sciatic nerve
. Inferior gluteal artery
. Superior gluteal nerve

Correct Answer & Explanation

. External iliac artery and vein

Explanation

The anterior-superior quadrant contains the external iliac artery and vein, making screw placement here dangerous. The posterior-superior quadrant is considered the 'safe zone' for acetabular screw placement.

Question 5763

Topic: 3. Adult Reconstruction (Hip & Knee)

During a trial reduction of a primary total knee arthroplasty (TKA), the surgeon notes that the patella subluxates laterally during flexion. A lateral retinacular release is being considered. Which of the following component malpositions is the most likely primary cause of this abnormal patellar tracking?

. Internal rotation of the femoral component
. External rotation of the tibial component
. Lateral placement of the patellar component
. Excessive external rotation of the femoral component
. Anterior translation of the tibial component

Correct Answer & Explanation

. Internal rotation of the femoral component

Explanation

Internal rotation of the femoral or tibial components, as well as medialization of the femoral component or lateralization of the patellar button, increases the Q-angle and drives lateral patellar maltracking.

Question 5764

Topic: 3. Adult Reconstruction (Hip & Knee)

A 79-year-old female presents to the emergency department with thigh pain and inability to bear weight after a mechanical fall. Radiographs demonstrate a displaced spiral fracture around the tip of her cementless THA stem. The stem shows subsidence and radiolucencies indicative of loosening. According to the Vancouver classification, what is the best surgical management?

. Open reduction and internal fixation with a lateral locking plate and cerclage cables
. Revision THA using a standard-length cementless stem
. Revision THA using a long diaphyseal-fitting stem bypassing the fracture by two cortical diameters
. Cortical strut allografting and cerclage cabling only
. Nonoperative management with a hinged knee brace

Correct Answer & Explanation

. Revision THA using a long diaphyseal-fitting stem bypassing the fracture by two cortical diameters

Explanation

This is a Vancouver B2 periprosthetic fracture (fracture around a loose stem with adequate bone stock). The gold standard treatment is revision to a long bypass stem that extends at least two cortical diameters past the most distal fracture line.

Question 5765

Topic: 3. Adult Reconstruction (Hip & Knee)

In total knee arthroplasty (TKA), the popliteal artery is at risk of iatrogenic injury. At which anatomical step of the procedure is the popliteal artery most vulnerable to direct laceration?

. Distal femoral resection
. Posterior cruciate ligament release
. Posterior capsular release at the level of the joint line
. Tibial plateau resection
. Lateral retinacular release

Correct Answer & Explanation

. Tibial plateau resection

Explanation

The popliteal artery is tethered by the middle genicular artery and lies in closest proximity to the posterior capsule at the level of the tibial plateau, making it highly vulnerable during the tibial bone cut.

Question 5766

Topic: Total Knee Arthroplasty (TKA)

A patient with a posterior-stabilized (PS) TKA develops restricted mid-flexion and a sense of 'tightness' despite adequate gap balancing. Postoperative radiographs reveal that the joint line has been significantly elevated. What is the primary kinematic consequence of joint line elevation in a PS TKA?

. Early cam-post engagement
. Late cam-post engagement
. Paradoxical anterior rollback
. Patella baja with secondary extension deficit
. Excessive posterior femoral rollback in deep flexion

Correct Answer & Explanation

. Early cam-post engagement

Explanation

Elevating the joint line in a PS knee moves the tibial post proximally relative to the femoral cam, causing early cam-post engagement. This restricts flexion and increases the risk of post wear or fracture.

Question 5767

Topic: 3. Adult Reconstruction (Hip & Knee)

A 50-year-old man presents with progressive groin pain 10 years after receiving a cementless THA with a conventional metal-on-polyethylene bearing. Radiographs reveal focal expansile osteolysis of the proximal femur. Which of the following cell types is the primary driver of this osteolytic process?

. Osteoblasts
. T-lymphocytes
. Macrophages
. Neutrophils
. Plasma cells

Correct Answer & Explanation

. Macrophages

Explanation

Wear-debris induced osteolysis is primarily mediated by macrophages, which phagocytose polyethylene particles and subsequently release cytokines (TNF-alpha, IL-1, IL-6) that stimulate osteoclastic bone resorption.

Question 5768

Topic: Total Hip Arthroplasty (THA)

A 45-year-old woman reports an audible 'squeaking' sound from her hip when walking, 3 years after a ceramic-on-ceramic THA. Which of the following biomechanical phenomena is most strongly associated with the onset of squeaking in these bearings?

. Stripe wear due to component edge loading
. Galvanic corrosion at the head-neck junction
. Excessive fluid film lubrication
. Delayed type IV hypersensitivity reaction
. Third-body wear from retained bone cement

Correct Answer & Explanation

. Stripe wear due to component edge loading

Explanation

Squeaking in ceramic-on-ceramic bearings is strongly associated with edge loading, which disrupts the fluid film lubrication and causes stripe wear. This is often due to cup malposition, such as excessive abduction or anteversion.

Question 5769

Topic: Total Knee Arthroplasty (TKA)

During gap balancing in a primary TKA, the surgeon notes that the flexion gap is symmetrically loose by 4 mm, while the extension gap is perfectly balanced. Which of the following adjustments is most appropriate to balance the knee?

. Increase the thickness of the tibial polyethylene insert
. Downsize the femoral component and augment the posterior condyles
. Upsize the femoral component to increase the anteroposterior dimension
. Translate the femoral component proximally
. Recut the distal femur to remove more bone

Correct Answer & Explanation

. Upsize the femoral component to increase the anteroposterior dimension

Explanation

A knee that is loose in flexion but balanced in extension requires an isolated decrease in the flexion gap. Upsizing the femoral component increases its AP dimension, filling the flexion gap without affecting the distal femoral extension gap.

Question 5770

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old man develops severe anterior groin pain when rising from a seated position or lifting his leg into a car, 1 year after a THA. Radiographs show the acetabular cup is in 45 degrees of abduction and 20 degrees of anteversion. An ultrasound-guided injection relieves the pain temporarily. What is the most likely etiology?

. Iliopsoas impingement secondary to anterior cup overhang
. Rectus femoris avulsion
. Trunnionosis at the head-neck taper
. Aseptic loosening of the femoral component
. Heterotopic ossification of the gluteus minimus

Correct Answer & Explanation

. Iliopsoas impingement secondary to anterior cup overhang

Explanation

Groin pain with active hip flexion (e.g., getting in/out of a car) coupled with symptom relief from an injection is classic for iliopsoas impingement. This is typically caused by a prominent anterior edge of the acetabular component.

Question 5771

Topic: Total Hip Arthroplasty (THA)

A patient with a failed metal-on-metal THA presents with systemic symptoms, including fatigue, visual impairment, and exertional dyspnea. Laboratory testing reveals elevated serum cobalt levels. Which of the following cardiac manifestations is a recognized complication of cobalt toxicity?

. Restrictive pericarditis
. Dilated cardiomyopathy
. Hypertrophic obstructive cardiomyopathy
. Aortic valve stenosis
. Constrictive endocarditis

Correct Answer & Explanation

. Dilated cardiomyopathy

Explanation

Systemic cobalt toxicity (arthroprosthetic cobaltism) can cause devastating neuro-ocular and cardiovascular effects. The classic cardiac manifestation is a toxic dilated cardiomyopathy, which can be fatal if the implants are not revised.

Question 5772

Topic: 3. Adult Reconstruction (Hip & Knee)
A 35-year-old man presents with chronic hip pain. Radiographs demonstrate a crescent sign in the superior femoral head with maintenance of the joint space. What is the most appropriate surgical treatment?
. Core decompression with bone marrow aspirate concentrate
. Total hip arthroplasty
. Non-vascularized fibular grafting
. Vascularized fibular grafting
. Proximal femoral osteotomy

Correct Answer & Explanation

. Total hip arthroplasty

Explanation

The presence of a crescent sign indicates subchondral collapse (Ficat Stage III). Once collapse has occurred, joint-preserving procedures (like core decompression) have a high failure rate, making THA the most reliable treatment.

Question 5773

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old patient who underwent a posterior-stabilized TKA two years ago presents with an audible and palpable 'clunk' in the anterior knee when extending the knee from a flexed position. The clunk reliably occurs at roughly 35 degrees of flexion. What is the primary pathology driving this phenomenon?

. Subluxation of the patella over the lateral femoral condyle
. Entrapment of a fibrous nodule within the intercondylar box
. Cam-post impingement during terminal extension
. Excessive polyethylene wear of the tibial spine
. Rupture of the patellar tendon

Correct Answer & Explanation

. Entrapment of a fibrous nodule within the intercondylar box

Explanation

'Patellar clunk syndrome' occurs in posterior-stabilized knees when a fibrous nodule forms on the undersurface of the quadriceps tendon or superior patellar pole. As the knee extends, this nodule catches in the intercondylar box and pops out with a clunk at 30-45 degrees of flexion.

Question 5774

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old woman is evaluated for a suspected periprosthetic joint infection (PJI) 2 years after a TKA. A synovial fluid aspirate is sent for analysis. According to the 2018 International Consensus Meeting (ICM) criteria, which of the following synovial fluid biomarkers is considered a major diagnostic criterion for chronic PJI?

. Synovial fluid leukocyte esterase
. Synovial fluid C-reactive protein (CRP)
. Synovial fluid Alpha-defensin
. Synovial fluid Interleukin-6 (IL-6)
. Synovial fluid D-dimer

Correct Answer & Explanation

. Synovial fluid Alpha-defensin

Explanation

Under the MSIS and ICM criteria, a positive synovial fluid alpha-defensin test (along with a sinus tract or two positive cultures) serves as a major criterion, possessing high sensitivity and specificity for diagnosing PJI.

Question 5775

Topic: Total Knee Arthroplasty (TKA)

A patient sustains an acute extensor mechanism rupture (complete patellar tendon avulsion) 3 weeks after a primary TKA. Due to poor tissue quality, a primary repair is augmented. Among the following options, which reconstruction technique provides the most reliable long-term clinical outcome?

. Primary repair with cerclage wire augmentation
. Reconstruction using synthetic mesh or an extensor mechanism allograft
. Gastrocnemius rotational flap
. Tibial tubercle osteotomy with proximal advancement
. Patellectomy and V-Y quadricepsplasty

Correct Answer & Explanation

. Reconstruction using synthetic mesh or an extensor mechanism allograft

Explanation

Primary repair of extensor mechanism ruptures post-TKA has an extremely high failure rate. Synthetic mesh (e.g., Marlex) or complete extensor mechanism allograft reconstruction are the preferred techniques with the most durable outcomes.

Question 5776

Topic: Total Hip Arthroplasty (THA)

Trunnionosis, or mechanically assisted crevice corrosion at the head-neck taper, has emerged as a significant cause of adverse local tissue reactions in modern THA. Which combination of implant factors is most associated with an increased risk of trunnionosis?

. Small femoral head diameter and large taper size
. Large femoral head diameter and high femoral offset
. Ceramic femoral head and titanium stem
. Short neck length and unpolished taper
. Standard offset and highly cross-linked polyethylene liner

Correct Answer & Explanation

. Large femoral head diameter and high femoral offset

Explanation

A large femoral head increases the frictional torque transmitted to the head-neck junction. Combined with a high offset, this maximizes bending moments and micromotion at the taper, strongly increasing the risk of trunnionosis.

Question 5777

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old man presents with an acute hematogenous periprosthetic joint infection of his THA. He has had symptoms for 5 days, and his implant has been in place for 3 years. Radiographs show well-fixed components. He undergoes Debridement, Antibiotics, and Implant Retention (DAIR). Which crucial surgical step must be included to maximize the success of DAIR?

. Exchange of the modular polyethylene liner and femoral head
. Application of an external fixator for 6 weeks
. Intraoperative radiation therapy
. Removal of the acetabular shell leaving the femoral stem
. Pulsatile lavage with 10% povidone-iodine only

Correct Answer & Explanation

. Exchange of the modular polyethylene liner and femoral head

Explanation

For a DAIR procedure to be successful, standard protocol dictates a thorough synovectomy, copious irrigation, and mandatory exchange of all modular components (liner and head) to eliminate biofilm harbored at the modular interfaces.

Question 5778

Topic: Total Knee Arthroplasty (TKA)

During a primary total knee arthroplasty (TKA), the surgeon evaluates patellar tracking after trial placement. The patella subluxates laterally during flexion despite a normal Q-angle preoperatively. Which of the following technical errors is the most likely cause of this abnormal patellar kinematics?

. External rotation of the femoral component
. Internal rotation of the femoral component
. Medialization of the femoral component
. Lateralization of the tibial tray
. External rotation of the tibial component

Correct Answer & Explanation

. Internal rotation of the femoral component

Explanation

Internal rotation of the femoral component shifts the trochlear groove medially, effectively increasing the Q-angle and causing lateral patellar maltracking. External rotation of the femoral and tibial components generally improves patellar tracking.

Question 5779

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old man presents with chronic pain and stiffness in his right knee 14 months after a primary TKA. Joint aspiration yields synovial fluid with a white blood cell count of 4,500 cells/mcL and 88% polymorphonuclear leukocytes (PMNs). Cultures are pending, but clinical suspicion for periprosthetic joint infection (PJI) is high. Assuming the implant is firmly fixed, what is the most appropriate definitive management?

. Debridement, antibiotics, and implant retention (DAIR)
. One-stage exchange arthroplasty without spacer
. Two-stage exchange arthroplasty
. Long-term intravenous antibiotic suppression
. Arthroscopic joint lavage

Correct Answer & Explanation

. Two-stage exchange arthroplasty

Explanation

The patient meets the criteria for a chronic PJI (WBC > 3,000 cells/mcL and > 80% PMNs after 4 weeks post-op). Two-stage exchange arthroplasty remains the gold standard in North America for chronic PJI to ensure eradication of the biofilm before reimplantation.

Question 5780

Topic: Total Hip Arthroplasty (THA)

A 45-year-old man underwent a primary THA using a ceramic-on-ceramic bearing. Three years postoperatively, he complains of an audible squeaking sound from the hip during deep flexion activities, though he is pain-free. What is the most significant risk factor for this phenomenon?

. High body mass index
. Decreased femoral head diameter
. Edge loading due to cup malposition
. Using a titanium femoral stem
. Impingement of the iliopsoas tendon

Correct Answer & Explanation

. Edge loading due to cup malposition

Explanation

Squeaking in ceramic-on-ceramic THA is strongly associated with edge loading, which typically occurs due to excessive steepness (high inclination) or malversion of the acetabular component. This leads to stripe wear and disruption of the fluid film lubrication.

Test Yourself

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

On this Page