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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 91 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 1801

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male is undergoing a total hip arthroplasty (THA). He has a history of severe heterotopic ossification (Brooker Class IV) following a previous contralateral THA. Which of the following prophylactic regimens is most appropriate and supported by the highest level of evidence?

. Indomethacin 25 mg PO TID for exactly 3 days postoperatively
. A single dose of 700-800 cGy radiation administered within 24 hours preoperatively or 72 hours postoperatively
. Oral alendronate daily for 6 weeks
. Low-molecular-weight heparin for 4 weeks combined with aspirin
. Vitamin C 500 mg PO daily for 50 days

Correct Answer & Explanation

. Indomethacin 25 mg PO TID for exactly 3 days postoperatively

Explanation

Prophylaxis against heterotopic ossification in high-risk patients is best achieved with either a single fraction of localized radiation therapy (700-800 cGy) given within 24 hours pre-op or 72 hours post-op, or a prolonged course of NSAIDs (e.g., Indomethacin 75 mg daily for 2 to 6 weeks). Three days of indomethacin is insufficient.

Question 1802

Topic: Total Knee Arthroplasty (TKA)

A 60-year-old male with isolated medial compartment knee osteoarthritis is evaluated for a unicompartmental knee arthroplasty (UKA).

According to classical indications, which of the following is considered a primary contraindication to performing a medial UKA?

. Patient age greater than 60 years
. Patient weight greater than 82 kg (180 lbs)
. Anterior cruciate ligament (ACL) deficiency
. A fixed varus deformity of 5 degrees
. A flexion contracture of 5 degrees

Correct Answer & Explanation

. Patient age greater than 60 years

Explanation

Historically, absolute contraindications for UKA included inflammatory arthropathy, ACL deficiency, fixed varus >10-15 degrees, and flexion contracture >15 degrees. ACL deficiency leads to excessive AP translation, accelerating wear and early failure of the relatively unconstrained medial UKA components. Note: Age and weight limits have been largely relaxed in modern practice.

Question 1803

Topic: 3. Adult Reconstruction (Hip & Knee)

Ceramic-on-ceramic (CoC) bearing surfaces in total hip arthroplasty offer extremely low volumetric wear rates. However, they are associated with unique complications not seen in other bearing couples. Which of the following is a recognized and unique complication of CoC bearings?

. Unpredictable systemic metal toxicity and ALVAL
. Severe trunnionosis leading to isolated head-neck taper failure
. Audible squeaking during normal functional activities
. In vivo delamination and subsurface cracking due to oxidative stress
. Accelerated backside wear of the titanium acetabular shell

Correct Answer & Explanation

. Unpredictable systemic metal toxicity and ALVAL

Explanation

Squeaking is a unique, well-documented complication of ceramic-on-ceramic bearings, occurring in approximately 1% to 10% of patients. It is thought to be multifactorial, related to edge loading, microseparation, component malposition, and loss of fluid film lubrication.

Question 1804

Topic: 3. Adult Reconstruction (Hip & Knee)
A 40-year-old male sustained a traumatic posterior hip dislocation 2 years ago. He now presents with worsening groin pain. Radiographs demonstrate a sclerotic femoral head with a clear subchondral lucent line (crescent sign), but the articular surface has not collapsed. According to the Ficat and Arlet classification for avascular necrosis, what stage is this disease?
. Stage I
. Stage II
. Stage III
. Stage IV
. Stage 0

Correct Answer & Explanation

. Stage III

Explanation

The Ficat and Arlet classification evaluates plain radiographs for osteonecrosis. Stage 0: Normal. Stage I: Normal x-ray, abnormal MRI/bone scan. Stage II: Cystic/sclerotic changes, normal contour. Stage III: Subchondral radiolucency (crescent sign) representing subchondral fracture, possibly with mild collapse but preserved joint space. Stage IV: Joint space narrowing and secondary osteoarthritis.

Question 1805

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male who underwent a primary total hip arthroplasty 5 years ago presents with persistent groin pain. Workup reveals elevated serum cobalt levels and a pseudotumor on MRI, consistent with trunnionosis. Which of the following factors is biomechanically most associated with an increased risk of mechanically assisted crevice corrosion at the head-neck junction?

. Use of a ceramic femoral head
. Decreased femoral offset
. Increased femoral head diameter
. Increased trunnion surface roughness
. Use of a cemented femoral stem

Correct Answer & Explanation

. Increased femoral head diameter

Explanation

Larger femoral head diameters increase the frictional torque at the bearing surface, translating to greater stress and micromotion at the head-neck junction (trunnion). This increased toggle predisposes the construct to mechanically assisted crevice corrosion.

Question 1806

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old male with a history of high-dose corticosteroid use presents with insidious onset groin pain. MRI of the hip reveals a subchondral crescentic lesion with a "double-line sign" on T2-weighted imaging. The inner hyperintense line of this classic sign represents which of the following?

. Sclerotic reactive bone
. Articular cartilage
. Granulation tissue
. Normal hematopoietic marrow
. Avascular necrotic bone

Correct Answer & Explanation

. Granulation tissue

Explanation

The double-line sign on T2-weighted MRI is pathognomonic for avascular necrosis (AVN) of the femoral head. The outer low-signal band represents sclerotic reactive bone, while the inner high-signal band represents vascularized granulation tissue trying to repair the necrotic zone.

Question 1807

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty using a measured resection technique, the trial components are placed. The surgeon notes that the joint is well-balanced and symmetric in full extension, but the flexion gap is unacceptably tight. Which of the following is the most appropriate intraoperative step to balance the knee?

. Decrease the anteroposterior size of the femoral component
. Resect more distal femur
. Increase the size of the femoral component
. Use a thicker tibial polyethylene insert
. Release the posterior capsule

Correct Answer & Explanation

. Decrease the anteroposterior size of the femoral component

Explanation

A tight flexion gap with a balanced extension gap implies the posterior femoral condyles are effectively "too thick." Decreasing the femoral component size (often with an anterior referencing system) translates the posterior condyles anteriorly, safely loosening the flexion gap without affecting extension.

Question 1808

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty, a surgeon accidentally sets the tibial component with 15 degrees of excessive internal rotation relative to the tibial tubercle. Which of the following complications is most directly caused by this rotational malalignment?

. Medial patellar subluxation
. Increased femoral roll-back during flexion
. Lateral patellar subluxation
. Excessive tightness of the lateral collateral ligament
. Posterior knee instability

Correct Answer & Explanation

. Medial patellar subluxation

Explanation

Internal rotation of the tibial component effectively externally rotates the tibial tubercle relative to the trochlear groove. This increases the Q-angle dynamically, leading to lateral patellar maltracking and subluxation.

Question 1809

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old female undergoes primary total knee arthroplasty (TKA) for severe fixed valgus osteoarthritis. During trial reduction, the knee is found to be excessively tight in both flexion and extension on the lateral side. According to the sequential lateral release technique, which specific lateral structure is primarily responsible for balancing the knee in BOTH flexion and extension?

. Iliotibial band
. Lateral collateral ligament
. Popliteus tendon
. Posterolateral capsule
. Lateral retinaculum

Correct Answer & Explanation

. Iliotibial band

Explanation

The lateral collateral ligament (LCL) provides primary restraint to varus stress in both flexion and extension. Therefore, in a fixed valgus knee that is tight in both the flexion and extension gaps, the LCL is the most critical structure to release. The popliteus primarily affects the flexion gap, while the iliotibial band (ITB) and posterolateral capsule primarily affect the extension gap.

Question 1810

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty for a severe varus deformity, trial components are placed. The knee is found to be well-balanced in extension but excessively tight medially in flexion. Which of the following medial structures should be released to specifically address the tight medial flexion gap?

. Posterior oblique ligament
. Posteromedial capsule
. Anterior portion of the superficial medial collateral ligament (sMCL)
. Semimembranosus insertion
. Pes anserinus tendons

Correct Answer & Explanation

. Posterior oblique ligament

Explanation

In the varus knee, the anterior portion of the superficial MCL is the primary restraint to flexion medially. Releasing it selectively opens the medial flexion gap without significantly affecting the extension gap.

Question 1811

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following component malpositions in a primary total knee arthroplasty (TKA) is most likely to result in lateral patellar subluxation or tracking issues?

. Internal rotation of the femoral component and internal rotation of the tibial component
. External rotation of the femoral component and internal rotation of the tibial component
. Internal rotation of the femoral component and external rotation of the tibial component
. External rotation of the femoral component and external rotation of the tibial component
. Medialization of the femoral component

Correct Answer & Explanation

. Internal rotation of the femoral component and internal rotation of the tibial component

Explanation

Internal rotation of either the femoral or tibial components increases the Q angle by relatively lateralizing the tibial tubercle or medializing the trochlear groove, both of which strongly predispose the patient to lateral patellar maltracking.

Question 1812

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with a feeling of instability 6 months after a primary total knee arthroplasty. Examination reveals the knee is stable in full extension but has 15 degrees of varus/valgus laxity at 90 degrees of flexion. Which of the following technical errors most likely caused this specific instability pattern?

. Excessive distal femoral resection
. Undersized femoral component in the AP dimension
. Inadequate proximal tibial resection
. Using a thicker tibial polyethylene
. Excessive posterior femoral offset

Correct Answer & Explanation

. Undersized femoral component in the AP dimension

Explanation

An undersized femoral component in the anteroposterior (AP) dimension excessively increases the flexion gap without affecting the extension gap. This results in isolated flexion instability.

Question 1813

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old female complains of an audible and painful "pop" in her knee when rising from a chair, 14 months after a posterior-stabilized total knee arthroplasty (TKA). Examination reveals a palpable catch at roughly 40 degrees of flexion as the knee extends. What is the most likely etiology?

. Polyethylene wear of the tibial insert
. Aseptic loosening of the patellar button
. Fibrous nodule formation at the superior pole of the patella
. Impingement of the popliteus tendon
. A patellar clunk due to an undersized femoral component

Correct Answer & Explanation

. Fibrous nodule formation at the superior pole of the patella

Explanation

Patellar clunk syndrome occurs primarily in posterior-stabilized TKA designs when a fibrous nodule forms at the superior pole of the patella. As the knee extends from a flexed position, this nodule catches in the intercondylar notch of the femoral component, usually around 30 to 45 degrees of flexion.

Question 1814

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with instability when descending stairs one year after a primary posterior-stabilized total knee arthroplasty (TKA). Clinical examination and stress radiographs demonstrate a well-balanced knee in full extension, but significant laxity is noted at 90 degrees of flexion. Which of the following intraoperative component adjustments would have best prevented this specific complication?

. Upsizing the anteroposterior (AP) dimension of the femoral component
. Increasing the thickness of the polyethylene insert
. Using a larger tibial tray
. Adding distal femoral augments
. Increasing the posterior slope of the tibial cut

Correct Answer & Explanation

. Upsizing the anteroposterior (AP) dimension of the femoral component

Explanation

Upsizing the AP dimension of the femoral component tightens the flexion gap without affecting the extension gap. Increasing polyethylene thickness or adding distal augments would alter the extension gap, which is already balanced in this patient.

Question 1815

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old female presents with a painful catching sensation in her anterior knee when moving from flexion to extension, exactly 14 months after undergoing a posterior-stabilized total knee arthroplasty (PS-TKA). What is the most likely etiology of her symptoms?

. Aseptic loosening of the patellar component
. A fibrous nodule in the superior pole of the patella engaging the intercondylar box
. Asymmetric polyethylene wear
. Patella alta due to an oversized femoral component
. Medial collateral ligament attenuation

Correct Answer & Explanation

. A fibrous nodule in the superior pole of the patella engaging the intercondylar box

Explanation

This describes 'patellar clunk syndrome,' a known complication of PS-TKA where a fibrous nodule forms at the superior pole of the patella. As the knee extends from flexion, the nodule catches in the femoral intercondylar box, causing a painful 'clunk.'

Question 1816

Topic: 3. Adult Reconstruction (Hip & Knee)

During a total knee arthroplasty (TKA), the surgeon inadvertently places both the femoral and tibial components in internal rotation. What is the most likely resulting complication?

. Patellar maltracking leading to lateral subluxation or dislocation
. Excessive tightening of the medial collateral ligament (MCL) in flexion
. Medial patellar subluxation
. Recurvatum deformity of the knee
. Anterior instability of the knee joint

Correct Answer & Explanation

. Patellar maltracking leading to lateral subluxation or dislocation

Explanation

Internal rotation of either the femoral or tibial component in TKA increases the Q-angle dynamically, leading to lateral patellar maltracking, anterior knee pain, and potentially lateral patellar subluxation or dislocation.

Question 1817

Topic: 3. Adult Reconstruction (Hip & Knee)

During a posterior stabilized total knee arthroplasty, the surgeon performs a posterior capsular release. The popliteal artery is at highest risk of injury in this region. At the level of the tibial cut, what is the anatomical relationship of the popliteal artery to the posterior capsule and popliteal vein?

. Directly lateral to the tibial nerve
. Lateral to the popliteal vein
. Posteromedial to the popliteal vein
. Directly anterior to the popliteal vein
. Medial to the tibial nerve

Correct Answer & Explanation

. Directly anterior to the popliteal vein

Explanation

At the level of the knee joint, the popliteal artery is the most anterior (deepest) structure in the popliteal fossa, lying directly anterior to the popliteal vein and immediately posterior to the joint capsule.

Question 1818

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary cruciate-retaining total knee arthroplasty, the trial reduction reveals that the knee is symmetric and balanced in extension but excessively tight in flexion. Which of the following is the most appropriate intraoperative adjustment?

. Recut the distal femur to remove more bone
. Release the posterior capsule
. Upsize the femoral component
. Increase the posterior slope of the tibial cut
. Release the superficial medial collateral ligament

Correct Answer & Explanation

. Increase the posterior slope of the tibial cut

Explanation

Increasing the posterior tibial slope effectively opens the flexion gap without significantly affecting the extension gap. Recutting the distal femur or releasing the posterior capsule would primarily affect the extension gap.

Question 1819

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old female with rheumatoid arthritis undergoes a primary total elbow arthroplasty (TEA) for severe joint destruction. She is educated post-operatively regarding lifelong activity modifications. Which of the following is the most commonly cited long-term mechanical complication of TEA?

. Ulnar nerve palsy
. Periprosthetic fracture
. Triceps rupture
. Aseptic loosening
. Heterotopic ossification

Correct Answer & Explanation

. Ulnar nerve palsy

Explanation

Aseptic loosening is the most common long-term complication and the most common reason for revision in total elbow arthroplasty (TEA). This is due to the high biomechanical forces across the constrained or semi-constrained hinges typically used in TEA. Patients are strictly limited to lifting a maximum of 5-10 lbs for a single event and 1-2 lbs repetitively for life to minimize this risk.

Question 1820

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old female with severe rheumatoid arthritis sustains a highly comminuted, osteopenic distal humerus fracture (AO/OTA 13-C3). She is treated with a total elbow arthroplasty (TEA). What is the most critical postoperative restriction she must strictly adhere to?

. No active elbow flexion for 6 weeks
. A permanent lifting restriction of 10-15 lbs for a single event and 5 lbs repetitively
. Avoidance of any triceps activation for 3 months
. Maintenance of the arm in a neutral rotation splint permanently
. Restriction of forearm pronation to 45 degrees

Correct Answer & Explanation

. A permanent lifting restriction of 10-15 lbs for a single event and 5 lbs repetitively

Explanation

Total elbow arthroplasty (TEA) for distal humerus fractures in the elderly is associated with excellent pain relief but carries strict lifetime lifting restrictions. Patients are generally restricted to a 5 lb repetitive and 10-15 lb singular lifting limit to prevent early aseptic loosening and implant failure.

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