Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 237 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 4721

Topic: Total Knee Arthroplasty (TKA)

A surgeon is utilizing a gap balancing technique during a primary TKA. After the proximal tibial cut is made and osteophytes are removed, the knee is brought into 90 degrees of flexion. Using a tensor, the flexion gap is noted to be asymmetric, being significantly tighter medially than laterally. What is the most appropriate next step to achieve a rectangular flexion gap before making the femoral cuts?

. Recut the proximal tibia with additional valgus
. Externally rotate the femoral AP cutting block
. Release the posterior cruciate ligament
. Downsize the femoral component
. Resect additional bone from the posterior medial condyle

Correct Answer & Explanation

. Externally rotate the femoral AP cutting block

Explanation

In the gap balancing technique, the goal is to create equal and rectangular extension and flexion gaps before making the final femoral cuts. If the flexion gap is tight medially after appropriate medial releases, externally rotating the femoral component (which removes more posterior lateral bone and less posterior medial bone) will balance the flexion gap.

Question 4722

Topic: Total Knee Arthroplasty (TKA)

A patient presents with a painful 'catch' and 'pop' when extending the knee from 45 degrees of flexion following a posterior-stabilized TKA. Which of the following implant design factors most contributes to this specific complication?

. High, lateralized patellar button placement
. Low femoral component flexion gap
. Posterior positioning of the femoral component
. Increased intercondylar box ratio (box width to intercondylar notch width)
. Sharp anterior edge of the femoral intercondylar box

Correct Answer & Explanation

. Sharp anterior edge of the femoral intercondylar box

Explanation

The clinical scenario describes Patellar Clunk Syndrome, a known complication of posterior-stabilized TKAs. It is caused by the formation of a fibrous nodule at the superior pole of the patella that catches in the intercondylar notch of the femoral component during extension. Risk factors include a sharp, unchamfered anterior edge of the femoral intercondylar box, a thin patella, and joint line elevation.

Question 4723

Topic: Total Hip Arthroplasty (THA)

During a primary Total Hip Arthroplasty (THA), restoring the center of rotation is critical. If the surgeon increases the femoral offset without altering the vertical height of the femoral head or leg length, what is the expected biomechanical effect on the abductor mechanism and the joint reaction force?

. Decreased abductor tension and increased joint reaction force
. Increased abductor moment arm and decreased joint reaction force
. Decreased abductor moment arm and decreased joint reaction force
. Increased abductor tension and increased joint reaction force
. No change in abductor moment arm but increased joint reaction force

Correct Answer & Explanation

. Increased abductor moment arm and decreased joint reaction force

Explanation

Increasing femoral offset lateralizes the greater trochanter, which increases the moment arm of the abductor muscles. This provides a mechanical advantage, requiring less abductor muscle force to balance the pelvis, which in turn significantly decreases the overall joint reaction force across the hip.

Question 4724

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old female complains of recurrent knee swelling, a feeling of the knee 'giving way' when walking down stairs, and anterior knee pain 2 years after a primary TKA. Examination reveals recurvatum and anteroposterior laxity at 90 degrees of flexion, but excellent stability in full extension. What intraoperative error most likely led to this presentation?

. Undersizing the femoral component in the anteroposterior dimension
. Oversizing the femoral component in the anteroposterior dimension
. Excessive resection of the distal femur
. Inadequate resection of the proximal tibia
. Internal rotation of the tibial component

Correct Answer & Explanation

. Undersizing the femoral component in the anteroposterior dimension

Explanation

The patient exhibits classic signs of flexion instability (laxity in flexion but stable in extension). This occurs when the flexion gap is larger than the extension gap. The most common intraoperative cause is undersizing the femoral component, which results in excessive posterior femoral condylar bone resection, thus increasing the flexion gap.

Question 4725

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old female reports a history of severe, blistering cutaneous reactions to costume jewelry and watch clasps. She requires a primary TKA for end-stage osteoarthritis. What is the most widely recommended perioperative management regarding her metal hypersensitivity?

. Proceed with a standard Cobalt-Chromium TKA as cutaneous hypersensitivity does not correlate with deep joint allergy
. Perform patch testing and proceed with Cobalt-Chromium if the test is negative
. Utilize a hypoallergenic (e.g., oxidized zirconium or titanium) implant without routine pre-operative testing
. Perform Lymphocyte Transformation Testing (LTT) and only use hypoallergenic implants if positive
. Administer prophylactic systemic corticosteroids for 4 weeks postoperatively using a CoCr implant

Correct Answer & Explanation

. Utilize a hypoallergenic (e.g., oxidized zirconium or titanium) implant without routine pre-operative testing

Explanation

In patients with a clear, severe clinical history of metal allergy (particularly nickel, which is present in CoCr alloys), it is generally recommended to bypass diagnostic testing (due to poor sensitivity/specificity of patch testing and LTT for deep joint spaces) and proceed directly with a hypoallergenic implant (such as oxidized zirconium or titanium) for arthroplasty.

Question 4726

Topic: Total Hip Arthroplasty (THA)
A revision THA is planned for an aseptic loose cup. Preoperative radiographs demonstrate superior migration of the hip center by 3.5 cm, complete destruction of the teardrop, and medial migration of the hip center past Kohler's line. What is the Paprosky classification and most appropriate reconstruction strategy?
. Type IIA; hemispherical cup with multiple screws
. Type IIB; hemispherical cup with particulate graft
. Type IIIA; hemispherical cup with a superior metal augment
. Type IIIB; custom triflange, cup-cage construct, or structural allograft
. Type IIC; jumbo cup with inferior screw fixation

Correct Answer & Explanation

. Type IIIB; custom triflange, cup-cage construct, or structural allograft

Explanation

The defect described involves >3 cm of superior migration, teardrop destruction, and medial migration past Kohler's line, indicating severe combined superior and medial bone loss with a nonsupportive rim. This represents a Paprosky Type IIIB defect (or potential pelvic discontinuity). Reconstruction typically requires a custom triflange, cup-cage construct, or an anti-protrusio cage with structural allograft.

Question 4727

Topic: Total Knee Arthroplasty (TKA)

A 62-year-old male is 8 weeks postoperative from a primary TKA. Despite strict adherence to aggressive physical therapy, his range of motion remains 10 to 75 degrees. Radiographs show well-positioned components without evidence of loosening or infection. What is the most appropriate next step in management?

. Continuation of current physical therapy for another 6 weeks without intervention
. Manipulation under anesthesia (MUA)
. Arthroscopic lysis of adhesions
. Open revision of the femoral component to downsize it
. Open lysis of adhesions and polyethylene liner exchange

Correct Answer & Explanation

. Manipulation under anesthesia (MUA)

Explanation

For the stiff TKA without a clear mechanical cause (e.g., component malposition, infection, or oversizing), Manipulation Under Anesthesia (MUA) is most effective when performed between 6 and 12 weeks postoperatively. Delaying intervention beyond 12 weeks significantly decreases the success rate of MUA.

Question 4728

Topic: 3. Adult Reconstruction (Hip & Knee)

During a revision TKA for aseptic loosening, the surgeon notes an absent anterior cruciate ligament, absent posterior cruciate ligament, and an incompetent medial collateral ligament (MCL). The extensor mechanism is intact. Significant metaphyseal bone loss is present. Which of the following implant constraints is absolutely indicated?

. Posterior stabilized (PS)
. Cruciate retaining (CR)
. Constrained condylar knee (CCK)
. Rotating hinge
. Fixed hinge

Correct Answer & Explanation

. Rotating hinge

Explanation

A Constrained Condylar Knee (CCK) relies on competent collateral ligaments (MCL and LCL) to provide varus/valgus stability, as it substitutes for the ACL and PCL. In the setting of an incompetent MCL (or LCL), a CCK will fail. A rotating hinge prosthesis is required as it provides intrinsic varus/valgus and rotational stability independent of the collateral ligaments.

Question 4729

Topic: Total Hip Arthroplasty (THA)

A 58-year-old female presents with persistent anterior groin pain 1 year after a primary THA. The pain is strongly exacerbated by active hip flexion against resistance and when lifting her leg to get into a car. Radiographs show a well-fixed, ingrown acetabular component with 15 degrees of anteversion. The anterior edge of the cup projects 4 mm beyond the native anterior acetabular rim. What is the most appropriate initial diagnostic/therapeutic step?

. Intra-articular hip injection of local anesthetic
. Image-guided injection of local anesthetic and corticosteroid into the iliopsoas bursa
. Electromyography (EMG) of the femoral nerve
. Revision of the acetabular component to increase retroversion
. Revision of the femoral stem to increase lateral offset

Correct Answer & Explanation

. Image-guided injection of local anesthetic and corticosteroid into the iliopsoas bursa

Explanation

The clinical presentation is classic for iliopsoas impingement against the anterior rim of the acetabular component. An image-guided diagnostic injection into the iliopsoas bursa is the most appropriate next step. It can confirm the diagnosis (via pain relief) and may provide lasting therapeutic benefit. If it fails, surgical release (tenotomy) is considered for mild prominences (<8-10 mm).

Question 4730

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old male presents with worsening knee pain 5 years after a primary TKA. The pain occurs exclusively with weight-bearing and is rapidly relieved by rest. ESR and CRP are within normal limits. Serial radiographs show a progressive radiolucent line of 3 mm in all zones around the tibial component. What is the most likely diagnosis?

. Periprosthetic joint infection (PJI)
. Aseptic loosening of the tibial component
. Patellar maltracking and clunk syndrome
. Complex regional pain syndrome (CRPS)
. Polyethylene wear without component loosening

Correct Answer & Explanation

. Aseptic loosening of the tibial component

Explanation

Pain that is present on weight-bearing and relieved by rest is the hallmark symptom of mechanical aseptic loosening. This is corroborated by normal inflammatory markers (ruling out PJI) and the radiographic presence of progressive, continuous radiolucent lines >2 mm in all zones around the component.

Question 4731

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following patient profiles represents the strongest and most widely accepted indication for the use of a dual mobility articulation in a primary total hip arthroplasty?

. A 50-year-old male with primary osteoarthritis and a desire to return to high-impact sports
. A 75-year-old female with profound osteoporosis and severe coxa vara
. A 68-year-old male with advanced Parkinson's disease and a prior history of recurrent falls
. A 45-year-old female with developmental dysplasia of the hip (Crowe IV)
. A 60-year-old male with avascular necrosis of the femoral head due to alcohol use

Correct Answer & Explanation

. A 68-year-old male with advanced Parkinson's disease and a prior history of recurrent falls

Explanation

Dual mobility articulations greatly increase the jump distance and range of motion before impingement, significantly reducing the risk of dislocation. They are heavily indicated in patients at a very high risk of instability, particularly those with neuromuscular disorders (like Parkinson's disease), severe cognitive impairment, or abductor deficiency.

Question 4732

Topic: 3. Adult Reconstruction (Hip & Knee)

In the design and surgical technique of Total Knee Arthroplasty (TKA), what is the primary biomechanical rationale for medializing the patellar component on the native resected patella?

. Decreases the Q-angle and improves patellar tracking
. Increases the Q-angle and increases the risk of lateral subluxation
. Increases the patellofemoral joint reaction force during deep flexion
. Moves the patellar ridge laterally, thereby increasing lateral retinacular tension
. Leads to early polyethylene wear on the medial facet due to point loading

Correct Answer & Explanation

. Decreases the Q-angle and improves patellar tracking

Explanation

Medializing the patellar dome during resurfacing shifts the native patellar bone laterally relative to the trochlear groove. This effectively decreases the Q-angle (the angle between the quadriceps pull and the patellar tendon), which reduces the lateral pull on the patella and improves overall patellar tracking within the trochlea.

Question 4733

Topic: 3. Adult Reconstruction (Hip & Knee)
During a complex revision THA, the surgeon identifies a transverse fracture through the acetabulum separating the superior and inferior hemipelvis. Intraoperatively, the superior and inferior halves move completely independently of one another. Which of the following is the most appropriate definitive management for this chronic pelvic discontinuity associated with severe bone loss in a medically fit patient?
. Jumbo hemispherical cup with multiple divergent screws
. Cup-cage construct or custom triflange acetabular component
. Isolated impaction bone grafting with a cemented polyethylene cup
. Resection arthroplasty (Girdlestone procedure)
. Standard cementless hemispherical cup utilizing a large diameter femoral head

Correct Answer & Explanation

. Cup-cage construct or custom triflange acetabular component

Explanation

Pelvic discontinuity is defined by the mechanical separation of the superior and inferior hemipelvis. In chronic cases with severe bone loss (e.g., Paprosky IIIB or IV), standard hemispherical cups cannot bridge the defect securely to allow healing. A cup-cage construct or a custom triflange acetabular component is required to provide rigid initial stability bridging the ilium and ischium/pubis.

Question 4734

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the Evidence-Based Musculoskeletal Infection Society (MSIS) criteria for diagnosing Periprosthetic Joint Infection (PJI), which of the following is considered a major criterion, providing definitive evidence of infection?

. Elevated serum C-reactive protein (CRP) > 10 mg/L and ESR > 30 mm/hr
. Elevated synovial fluid white blood cell count > 3,000 cells/µL
. Positive alpha-defensin test from synovial fluid
. Two positive periprosthetic tissue cultures with phenotypically identical organisms
. Elevated synovial fluid polymorphonuclear percentage (PMN%) > 80%

Correct Answer & Explanation

. Two positive periprosthetic tissue cultures with phenotypically identical organisms

Explanation

Under the MSIS criteria, the major criteria for definitive PJI are: 1) Two positive periprosthetic cultures with phenotypically identical organisms, or 2) A sinus tract communicating directly with the joint space. All other listed options (elevated CRP/ESR, elevated synovial WBC/PMN%, and positive alpha-defensin) serve as minor criteria, which must be combined to form a diagnosis if major criteria are unmet.

Question 4735

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old female with severe rheumatoid arthritis presents with bilateral hip pain. Radiographs reveal bilateral severe protrusio acetabuli (Kohler's line is crossed by the femoral head). During primary THA, which of the following is the most appropriate surgical technique to address the medial acetabular wall defect?

. Ream the acetabulum deeply to engage the remaining medial wall for fixation
. Use an undersized small-diameter cup without bone grafting to fit the defect
. Utilize impacted morselized cancellous bone graft to lateralize the center of rotation, followed by standard cup placement
. Insertion of an anti-protrusio cage without the use of bone graft
. Resect the femoral head and perform a bipolar hemiarthroplasty to allow native bone remodeling

Correct Answer & Explanation

. Utilize impacted morselized cancellous bone graft to lateralize the center of rotation, followed by standard cup placement

Explanation

In primary THA for protrusio acetabuli, the goal is to restore the anatomical center of rotation by lateralizing the hip center. This is best achieved by placing impacted morselized cancellous bone graft (often autograft from the resected femoral head) into the medial defect, and placing a standard hemispherical cementless cup on the peripheral rim, ensuring rim fit.

Question 4736

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty, the surgeon assesses the gaps and finds the knee is tight in flexion but symmetric and balanced in extension. Which of the following steps is the most appropriate to balance the knee?

. Increase the posterior tibial slope
. Decrease the posterior tibial slope
. Recut the distal femur to remove more bone
. Release the posterior capsule
. Upsize the femoral component

Correct Answer & Explanation

. Increase the posterior tibial slope

Explanation

Increasing the posterior tibial slope selectively increases the flexion gap without significantly altering the extension gap. Downsizing the femoral component or releasing the PCL can also address a tight flexion gap.

Question 4737

Topic: Total Hip Arthroplasty (THA)

A 65-year-old active male underwent a total hip arthroplasty with a ceramic-on-ceramic bearing. Three years postoperatively, he complains of an audible squeaking sound from the hip during walking, but denies pain. What is the most significant risk factor for this phenomenon?

. Component malposition leading to edge loading
. Large femoral head size
. Use of a highly cross-linked polyethylene liner
. Patient's body mass index (BMI)
. Leg length discrepancy

Correct Answer & Explanation

. Component malposition leading to edge loading

Explanation

Squeaking in ceramic-on-ceramic bearings is primarily associated with edge loading due to component malposition, particularly excessive acetabular cup anteversion or abduction.

Question 4738

Topic: 3. Adult Reconstruction (Hip & Knee)

To optimize patellar tracking during a total knee arthroplasty, the femoral component is traditionally externally rotated relative to the posterior condylar axis. What is the primary anatomical landmark used to establish this rotation?

. Surgical transepicondylar axis
. Clinical transepicondylar axis
. Anteroposterior (Whiteside's) line
. Posterior condylar axis
. Tibial tubercle

Correct Answer & Explanation

. Surgical transepicondylar axis

Explanation

The surgical transepicondylar axis, connecting the lateral epicondylar prominence and the medial sulcus, is the most reliable landmark for setting femoral component external rotation to optimize patellar tracking.

Question 4739

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old female presents with severe groin pain 6 years after a metal-on-metal total hip arthroplasty. Aspiration yields fluid with low cell count but imaging shows a large cystic mass extending into the pelvis. What is the most likely underlying pathophysiological mechanism?

. Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)
. Particulate debris induced macrophage activation
. Acute bacterial infection
. Galvanic corrosion of the trunnion
. Heterotopic ossification

Correct Answer & Explanation

. Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL)

Explanation

Metal-on-metal implants can cause an adverse local tissue reaction (ALTR) or pseudotumor. This is histologically characterized by ALVAL, driven by a type IV hypersensitivity response to metal ions.

Question 4740

Topic: 3. Adult Reconstruction (Hip & Knee)

A patient requires revision of a total hip arthroplasty due to an extensively loose, cemented femoral stem with deficient metaphyseal bone but an intact diaphysis (Vancouver Type B2). Which of the following is the most appropriate reconstructive option for the femur?

. Extensively porous-coated cylindrical cementless stem
. Standard length cemented stem with impaction grafting
. Proximally porous-coated tapered wedge stem
. Resection arthroplasty
. Open reduction and internal fixation with a locking plate

Correct Answer & Explanation

. Extensively porous-coated cylindrical cementless stem

Explanation

A Vancouver B2 periprosthetic fracture involves a loose stem with adequate distal bone stock. The standard of care is revision using a diaphyseal engaging implant, such as an extensively porous-coated cementless stem.

Test Yourself

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

On this Page