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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 164 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 3261

Topic: 3. Adult Reconstruction (Hip & Knee)

To minimize the risk of dislocation after total hip arthroplasty, the acetabular component should ideally be placed within the 'Lewinnek safe zone'. Which of the following represents these correct target angles?

. 40 ± 10 degrees of inclination and 15 ± 10 degrees of anteversion
. 45 ± 10 degrees of inclination and 25 ± 10 degrees of anteversion
. 30 ± 10 degrees of inclination and 10 ± 10 degrees of anteversion
. 50 ± 10 degrees of inclination and 15 ± 10 degrees of anteversion
. 40 ± 10 degrees of inclination and 0 ± 10 degrees of anteversion

Correct Answer & Explanation

. 40 ± 10 degrees of inclination and 15 ± 10 degrees of anteversion

Explanation

The classic Lewinnek safe zone for acetabular cup placement dictates an inclination (abduction) of 40 ± 10 degrees and an anteversion of 15 ± 10 degrees to reduce the risk of postoperative dislocation.

Question 3262

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old female complains of persistent groin pain 1 year after an uncomplicated total hip arthroplasty. The pain is particularly sharp when she lifts her leg to get out of a car or performs an active straight leg raise. Radiographs reveal a prominent anterior edge of the acetabular component. What is the most likely etiology of her pain?

. Heterotopic ossification
. Aseptic loosening of the femoral stem
. Iliopsoas impingement
. Adverse local tissue reaction
. Femoral nerve entrapment

Correct Answer & Explanation

. Heterotopic ossification

Explanation

Groin pain provoked by active hip flexion (e.g., straight leg raise) following THA, especially in the presence of an anteriorly prominent or retroverted acetabular cup, is highly characteristic of iliopsoas tendon impingement.

Question 3263

Topic: 3. Adult Reconstruction (Hip & Knee)

Following a total hip arthroplasty via a posterior approach, a patient is noted to have a foot drop and inability to extend the great toe. The peroneal division of the sciatic nerve is injured. Which anatomic feature explains why the peroneal division is more susceptible to injury than the tibial division?

. It has more connective tissue separating the fascicles.
. It is positioned more medially within the sciatic sheath.
. It has a relatively fixed position at the fibular head.
. It is primarily composed of sensory fibers.
. It receives direct vascular supply exclusively from the inferior gluteal artery.

Correct Answer & Explanation

. It has more connective tissue separating the fascicles.

Explanation

The peroneal division of the sciatic nerve is more vulnerable to stretch injuries during THA because it is tethered distally at the fibular head, lies more laterally (closer to the retractors), and has larger fascicles with less protective connective tissue than the tibial division.

Question 3264

Topic: Total Hip Arthroplasty (THA)

A patient presents with recurrent anterior dislocations following a total hip arthroplasty performed via a posterior approach. Radiographs show the acetabular component has 55 degrees of inclination and 45 degrees of anteversion. What is the primary cause of dislocation in this patient?

. Insufficient femoral offset
. Excessive acetabular anteversion
. Retroverted femoral stem
. Abductor deficiency
. Capsular laxity

Correct Answer & Explanation

. Insufficient femoral offset

Explanation

Excessive acetabular anteversion (normal target is 15-20 degrees) predisposes the hip to anterior dislocation. This typically occurs when the hip is placed in extension and external rotation.

Question 3265

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male with a metal-on-polyethylene total hip arthroplasty presents with groin pain 5 years postoperatively. Aspiration yields cloudy fluid with negative cultures but elevated serum cobalt levels. MRI demonstrates a large cystic pseudotumor. What is the most likely diagnosis?

. Periprosthetic joint infection
. Trunnionosis
. Polyethylene wear debris osteolysis
. Ceramic squeaking
. Iliopsoas impingement

Correct Answer & Explanation

. Periprosthetic joint infection

Explanation

Trunnionosis is mechanically assisted crevice corrosion at the modular head-neck junction. It can cause an adverse local tissue reaction (ALTR) or pseudotumor even in metal-on-polyethylene bearings, evidenced by elevated serum metal ions.

Question 3266

Topic: Total Hip Arthroplasty (THA)

A 45-year-old female undergoes total hip arthroplasty with a ceramic-on-ceramic bearing. Three years later, she complains of a reproducible squeaking noise during gait. Which of the following factors is most strongly associated with this phenomenon?

. Femoral stem retroversion
. Acetabular component malposition
. Elevated body mass index
. Small femoral head size
. Short femoral neck offset

Correct Answer & Explanation

. Femoral stem retroversion

Explanation

Squeaking in ceramic-on-ceramic THA is most strongly associated with edge loading. This is typically due to acetabular component malposition, particularly excessive inclination or anteversion, or impingement.

Question 3267

Topic: 3. Adult Reconstruction (Hip & Knee)



A 75-year-old female falls and sustains a periprosthetic femur fracture around a cemented THA stem. Radiographs show a fracture around the stem tip, a loose femoral component, and excellent distal bone stock (Vancouver B2). What is the optimal surgical management?

. Open reduction internal fixation with cables and plates
. Revision to a long cemented stem
. Revision to a distally fixing porous coated stem
. Allograft strut placement alone
. Resection arthroplasty

Correct Answer & Explanation

. Open reduction internal fixation with cables and plates

Explanation

A Vancouver B2 fracture is characterized by a fracture around the stem with a loose stem but adequate bone stock. The standard of care is revision of the femoral component to a diaphyseal bypassing, distally fixing uncemented stem.

Question 3268

Topic: Total Hip Arthroplasty (THA)

A patient reports persistent groin pain and catching when actively rising from a seated position following an uncemented THA. A diagnostic injection of lidocaine into the iliopsoas bursa provides complete relief. What radiographic finding is most likely present?

. Excessive cup retroversion
. Prominent anterior acetabular component edge
. Subsidence of the femoral stem
. Anterior heterotopic ossification
. Shortened leg length

Correct Answer & Explanation

. Excessive cup retroversion

Explanation

Iliopsoas impingement is typically caused by a prominent anterior edge of the acetabular component catching the tendon. It classically presents with groin pain upon active hip flexion and is diagnosed via image-guided injection.

Question 3269

Topic: Total Hip Arthroplasty (THA)

Based on the HEALTH trial and recent evidence, which of the following is true regarding THA compared to hemiarthroplasty for displaced femoral neck fractures in active older adults?

. THA has a significantly lower risk of dislocation
. Hemiarthroplasty provides significantly better functional outcomes
. THA has a higher risk of dislocation but similar mortality
. THA is associated with significantly lower mortality at 1 year
. Hemiarthroplasty requires a longer operative time

Correct Answer & Explanation

. THA has a significantly lower risk of dislocation

Explanation

THA for displaced femoral neck fractures yields a higher risk of dislocation compared to hemiarthroplasty. However, overall mortality is similar, and THA may offer slight functional benefits in very active patients.

Question 3270

Topic: 3. Adult Reconstruction (Hip & Knee)

A patient presents 6 weeks after a primary THA with a draining sinus tract communicating directly with the joint. According to the 2018 International Consensus Meeting (ICM) criteria, what is the next best step for diagnosing infection?

. Check serum ESR and CRP
. Perform hip aspiration for cell count
. Obtain alpha-defensin levels
. No further diagnostic tests are required to confirm the diagnosis of PJI
. Perform a 3-phase bone scan

Correct Answer & Explanation

. Check serum ESR and CRP

Explanation

A sinus tract communicating with the joint is a major criterion for periprosthetic joint infection (PJI). It definitively establishes the diagnosis, meaning no further diagnostic testing is required to confirm PJI before planning surgical intervention.

Question 3271

Topic: 3. Adult Reconstruction (Hip & Knee)

Histologic evaluation of periprosthetic tissue from a failed metal-on-metal THA demonstrates an adverse local tissue reaction (ALTR). Which cellular finding is characteristic of an Aseptic Lymphocyte-dominated Vasculitis-Associated Lesion (ALVAL)?

. Massive neutrophil infiltration
. Abundant foamy macrophages with polyethylene particles
. Perivascular lymphocytic infiltrate
. Eosinophilic granulomas
. Caseating granulomas

Correct Answer & Explanation

. Massive neutrophil infiltration

Explanation

ALVAL is a type IV delayed hypersensitivity reaction to metal ions. Histologically, it is classically characterized by a robust perivascular lymphocytic infiltrate and varying degrees of tissue necrosis.

Question 3272

Topic: Total Hip Arthroplasty (THA)

A patient complains of an apparent leg length discrepancy immediately following a primary THA. Examination reveals the operative leg appears longer, but true leg length measurement (ASIS to medial malleolus) is equal bilaterally. What is the most likely cause?

. Excessive femoral offset
. True lengthening of the femur
. Subsidence of the femoral stem
. Pelvic obliquity secondary to adductor contracture or spine deformity
. Sciatic nerve tethering

Correct Answer & Explanation

. Excessive femoral offset

Explanation

An apparent leg length discrepancy with equal true leg lengths is often caused by pelvic obliquity. This can result from preexisting spinal deformity, adductor contracture, or abductor weakness, and often resolves with targeted physical therapy.

Question 3273

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old woman presents with recurrent posterior dislocations following a primary total hip arthroplasty. Evaluation reveals the acetabular component is placed in 5 degrees of retroversion and 40 degrees of inclination. During which of the following activities is she at the highest risk for dislocation?

. Hip extension, external rotation, and adduction
. Hip flexion, internal rotation, and adduction
. Hip extension, internal rotation, and abduction
. Hip flexion, external rotation, and abduction
. Hip extension, external rotation, and abduction

Correct Answer & Explanation

. Hip extension, external rotation, and adduction

Explanation

Posterior dislocation of a THA is most commonly associated with hip flexion, internal rotation, and adduction. A retroverted acetabular component exacerbates this risk by failing to provide adequate posterior head coverage during these specific motions.

Question 3274

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old man who underwent a metal-on-polyethylene total hip arthroplasty 5 years ago presents with new-onset groin pain and a palpable fluid collection. Radiographs show well-fixed components with a large femoral head and a modular neck. Laboratory testing reveals elevated serum cobalt and normal chromium levels. What is the most likely diagnosis?

. Periprosthetic joint infection
. Polyethylene wear and osteolysis
. Trunnionosis
. Aseptic loosening of the acetabular component
. Iliopsoas tendinitis

Correct Answer & Explanation

. Periprosthetic joint infection

Explanation

Trunnionosis is caused by mechanically assisted crevice corrosion at the modular head-neck or neck-stem taper junction. It is characterized by adverse local tissue reactions (pseudotumors) and isolated elevated serum cobalt levels out of proportion to chromium, even in metal-on-polyethylene bearings.

Question 3275

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old cognitively intact, highly active community ambulator sustains a displaced femoral neck fracture. Compared to a cemented bipolar hemiarthroplasty, surgical treatment with a total hip arthroplasty (THA) is most likely associated with which of the following?

. Lower rate of postoperative dislocation
. Higher rate of acetabular erosion
. Better long-term functional outcomes and lower reoperation rates
. Decreased operative time and blood loss
. Increased risk of avascular necrosis of the native acetabulum

Correct Answer & Explanation

. Lower rate of postoperative dislocation

Explanation

In active, cognitively intact older adults with displaced femoral neck fractures, THA provides better long-term functional outcomes (e.g., Harris Hip Scores) and lower reoperation rates compared to hemiarthroplasty. However, THA does carry a higher risk of dislocation, longer operative time, and greater blood loss.

Question 3276

Topic: 3. Adult Reconstruction (Hip & Knee)

Following a primary total hip arthroplasty performed via a posterior approach, the patient is noted in the recovery room to have an inability to dorsiflex the great toe or evert the foot. Sensation is decreased over the anterolateral leg and the dorsum of the foot. Which specific neural structure is most likely injured?

. Femoral nerve
. Obturator nerve
. Tibial division of the sciatic nerve
. Common peroneal division of the sciatic nerve
. Superior gluteal nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

The common peroneal division of the sciatic nerve is uniquely susceptible to stretch injury during THA, particularly when the limb is lengthened or retractors are placed posteriorly. It provides motor innervation to the ankle dorsiflexors and everters, and sensory innervation to the anterolateral leg and dorsum of the foot.

Question 3277

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 27 shows the radiograph of a 68-year-old woman with a history of rheumatoid arthritis who was injured in a fall. History reveals that she has been asymptomatic since undergoing a left total knee arthroplasty 9 years ago. Management should consist of

. skeletal traction.
. immediate application of a cast brace.
. a retrograde supracondylar nail.
. revision total knee replacement.
. resection arthrodesis.

Correct Answer & Explanation

. skeletal traction.

Explanation

A supracondylar fracture of the femur that occurs after total knee replacement can be treated effectively by a number of methods. For this fracture, the use of a retrograde supracondylar nail has been found to be effective in several series. The treatment of these complex injuries needs to be individualized based on the stability of the implant, the quality of the bone, and the extent of comminution of the fracture. Revision with the use of an unstemmed implant will not result in effective stabilization of the knee or the fracture.

Question 3278

Topic: 3. Adult Reconstruction (Hip & Knee)

A healthy 32-year-old male sustains a displaced intracapsular femoral neck fracture after falling from a height.

What is the most appropriate definitive management for this patient?

. Urgent open or closed reduction and internal fixation
. Total hip arthroplasty
. Bipolar hemiarthroplasty
. Unipolar hemiarthroplasty
. Non-weight bearing and delayed internal fixation at 2 weeks

Correct Answer & Explanation

. Urgent open or closed reduction and internal fixation

Explanation

In physiologically young and active patients, a displaced femoral neck fracture is considered a surgical urgency to preserve the native hip joint. Urgent anatomic reduction and stable internal fixation minimize the risk of avascular necrosis and nonunion.

Question 3279

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old male with a history of corticosteroid use presents with bilateral hip pain.

Imaging confirms Ficat Stage II avascular necrosis of the femoral head with no evidence of subchondral collapse. Which of the following is the most appropriate initial surgical intervention?

. Total hip arthroplasty
. Core decompression with or without bone grafting
. Resurfacing arthroplasty
. Proximal femoral varus osteotomy
. Arthroscopic labral debridement

Correct Answer & Explanation

. Total hip arthroplasty

Explanation

Ficat Stage II avascular necrosis involves cystic and sclerotic changes without subchondral collapse. Core decompression is indicated to reduce intraosseous pressure and promote revascularization before structural failure occurs.

Question 3280

Topic: 3. Adult Reconstruction (Hip & Knee)

During a total hip arthroplasty, the surgeon is inserting screws for supplemental acetabular shell fixation. According to the quadrant system described by Wasielewski, which quadrant represents the 'safe zone' to minimize risk of neurovascular injury?

. Posterosuperior quadrant
. Posteroinferior quadrant
. Anterosuperior quadrant
. Anteroinferior quadrant
. Central fossa

Correct Answer & Explanation

. Posterosuperior quadrant

Explanation

The posterosuperior quadrant is considered the safe zone for acetabular screw placement. The posteroinferior quadrant risks the sciatic nerve and internal pudendal vessels, while the anterior quadrants risk the external iliac and obturator vessels.

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