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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 156 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 3101

Topic: 3. Adult Reconstruction (Hip & Knee)

During preoperative templating for a total hip arthroplasty, the surgeon notes that increasing the femoral offset of the implant will result in which of the following biomechanical changes?

. Increased joint reaction force
. Decreased tension in the abductor musculature
. Increased force required by the abductors to maintain a level pelvis
. Medialization of the femoral shaft
. Decreased wear on the polyethylene liner

Correct Answer & Explanation

. Increased joint reaction force

Explanation

Increasing femoral offset increases the lever arm of the abductor muscles, which decreases the force they must generate to balance the pelvis. This simultaneously decreases the resultant joint reaction force across the hip.

Question 3102

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following vessels provides the predominant blood supply to the weight-bearing dome of the adult femoral head?

. Artery of the ligamentum teres
. Inferior gluteal artery
. Ascending branch of the lateral circumflex femoral artery
. Deep branch of the medial circumflex femoral artery
. First perforating branch of the profunda femoris

Correct Answer & Explanation

. Artery of the ligamentum teres

Explanation

The deep branch of the medial circumflex femoral artery (MFCA) provides the primary blood supply to the adult femoral head via the lateral epiphyseal artery. Injury to this vessel during trauma or surgery significantly increases the risk of avascular necrosis.

Question 3103

Topic: 3. Adult Reconstruction (Hip & Knee)

A healthy, active 72-year-old woman sustains a Garden IV femoral neck fracture. Compared to bipolar hemiarthroplasty, treatment with total hip arthroplasty (THA) is associated with a higher rate of which of the following?

. Dislocation
. Acetabular erosion
. Need for revision surgery
. Groin pain
. Mortality at 1 year

Correct Answer & Explanation

. Dislocation

Explanation

In active elderly patients with displaced femoral neck fractures, THA provides better functional outcomes and lower revision rates than hemiarthroplasty, but it carries a higher risk of postoperative dislocation.

Question 3104

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old man undergoes total hip arthroplasty. Six months postoperatively, he presents with a squeaking sound from his hip during normal walking. He has no pain, and radiographs show well-fixed components. Which bearing surface was most likely used?

. Metal-on-polyethylene
. Ceramic-on-polyethylene
. Ceramic-on-ceramic
. Metal-on-metal
. Oxidized zirconium-on-polyethylene

Correct Answer & Explanation

. Metal-on-polyethylene

Explanation

Squeaking is a known complication specific to ceramic-on-ceramic articulations, with a reported incidence of up to 10%. It is generally benign if asymptomatic but may be associated with component malpositioning or edge loading.

Question 3105

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old woman with rheumatoid arthritis is scheduled for a total hip arthroplasty. Preoperative radiographs reveal severe protrusio acetabuli. During acetabular reconstruction, what is the most appropriate management to restore the anatomic center of rotation?

. Use an extra-large hemispherical cup
. Medialize the cup further to ensure complete coverage
. Impact morselized bone graft into the medial defect and place a hemispherical cup
. Use a bipolar hemiarthroplasty
. Place a customized triflange component

Correct Answer & Explanation

. Use an extra-large hemispherical cup

Explanation

The primary goal in treating protrusio acetabuli during THA is restoring the center of rotation laterally. This is best achieved using impacted morselized cancellous bone graft in the medial defect combined with a hemispherical cup.

Question 3106

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old man presents with painful clicking and groin pain 5 years after an uncemented total hip arthroplasty. Radiographs show a well-fixed femoral stem and a well-fixed acetabular shell. Blood work shows markedly elevated serum cobalt and mildly elevated chromium. What is the most likely diagnosis?

. Periprosthetic joint infection
. Trunnionosis
. Polyethylene osteolysis
. ALVAL reaction to a metal-on-metal bearing
. Aseptic loosening

Correct Answer & Explanation

. Periprosthetic joint infection

Explanation

Trunnionosis (mechanically assisted crevice corrosion) occurs at the modular head-neck junction. It typically presents with elevated cobalt levels disproportionate to chromium levels in patients with metal heads on titanium stems.

Question 3107

Topic: 3. Adult Reconstruction (Hip & Knee)

Three weeks after a primary total hip arthroplasty via a posterior approach, a 65-year-old woman presents with sudden hip pain and shortening of the limb. Radiographs show a posterior dislocation. Closed reduction is successful. What is the most appropriate initial management?

. Immediate revision of the acetabular component
. Immediate revision of the femoral component
. Placement of an abduction brace and strict hip precautions
. Prophylactic administration of indomethacin
. Conversion to a constrained liner

Correct Answer & Explanation

. Immediate revision of the acetabular component

Explanation

For a first-time posterior dislocation early after THA without component malposition, closed reduction followed by nonoperative management with an abduction brace and strict adherence to hip precautions is the standard initial treatment.

Question 3108

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old man presents with a Vancouver B2 periprosthetic femur fracture around his uncemented total hip arthroplasty 6 years after the index procedure. Radiographs show a fracture around a loose stem with adequate distal bone stock. What is the treatment of choice?

. Open reduction and internal fixation with a locking plate
. Cortical strut allografting alone
. Revision to a long, extensively porous-coated or fluted tapered stem
. Impaction bone grafting and cementation of a new standard-length stem
. Removal of the prosthesis and Girdlestone resection arthroplasty

Correct Answer & Explanation

. Open reduction and internal fixation with a locking plate

Explanation

A Vancouver B2 fracture involves a loose stem with good bone stock. The standard of care is revision arthroplasty using a long, diaphyseal-engaging stem (extensively porous-coated or fluted tapered) bypassing the fracture.

Question 3109

Topic: 3. Adult Reconstruction (Hip & Knee)

When evaluating an anteroposterior pelvis radiograph to assess acetabular component positioning post-total hip arthroplasty, the \"safe zone\" for acetabular abduction (inclination) and anteversion, as historically described by Lewinnek, is:

. 30 degrees +/- 10 degrees inclination and 10 degrees +/- 10 degrees anteversion
. 40 degrees +/- 10 degrees inclination and 15 degrees +/- 10 degrees anteversion
. 45 degrees +/- 10 degrees inclination and 25 degrees +/- 10 degrees anteversion
. 50 degrees +/- 10 degrees inclination and 20 degrees +/- 10 degrees anteversion
. 35 degrees +/- 10 degrees inclination and 5 degrees +/- 10 degrees anteversion

Correct Answer & Explanation

. 30 degrees +/- 10 degrees inclination and 10 degrees +/- 10 degrees anteversion

Explanation

The Lewinnek safe zone for acetabular component placement in THA is historically defined as an inclination (abduction) of 40 degrees (+/- 10 degrees) and an anteversion of 15 degrees (+/- 10 degrees).

Question 3110

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old man undergoes a total hip arthroplasty via a direct anterior approach. Postoperatively, he complains of numbness and a burning sensation over the anterolateral aspect of his thigh. Motor function is completely intact. Which nerve was most likely stretched or injured?

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

Correct Answer & Explanation

. Femoral nerve

Explanation

The lateral femoral cutaneous nerve is at risk during the direct anterior approach to the hip. Injury results in meralgia paresthetica, presenting as sensory deficits or burning pain over the anterolateral thigh with no motor weakness.

Question 3111

Topic: 3. Adult Reconstruction (Hip & Knee)

A 50-year-old woman undergoes a total hip arthroplasty via a posterior approach. During the approach, the short external rotators are released. The surgeon must be particularly careful to protect the sciatic nerve, which typically exits the pelvis:

. Superior to the piriformis muscle
. Through the greater sciatic foramen, inferior to the piriformis muscle
. Through the lesser sciatic foramen
. Between the superior gemellus and obturator internus
. Anterior to the quadratus femoris

Correct Answer & Explanation

. Superior to the piriformis muscle

Explanation

The sciatic nerve exits the pelvis through the greater sciatic foramen, typically emerging inferior to the piriformis muscle before traveling deep to the gluteus maximus.

Question 3112

Topic: 3. Adult Reconstruction (Hip & Knee)

An active, independent 72-year-old woman sustains a displaced femoral neck fracture. Compared to bipolar hemiarthroplasty, treatment with total hip arthroplasty (THA) is most closely associated with which of the following outcomes?

. Lower risk of postoperative dislocation
. Lower rate of revision surgery
. Shorter operative time
. Decreased blood loss
. Higher incidence of progressive acetabular wear

Correct Answer & Explanation

. Lower risk of postoperative dislocation

Explanation

In active elderly patients with displaced femoral neck fractures, THA is associated with better long-term functional outcomes and lower revision rates compared to hemiarthroplasty. However, THA carries a higher risk of postoperative dislocation, longer operative times, and increased blood loss.

Question 3113

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old man presents with groin pain 5 years after undergoing a metal-on-polyethylene total hip arthroplasty with a large diameter (36 mm) metal head. Aspiration yields cloudy fluid with negative cultures. MRI with metal artifact reduction shows a solid pseudotumor. What is the most likely cause?

. Polyethylene wear
. Trunnionosis
. Low-grade deep infection
. Iliopsoas impingement
. Aseptic component loosening

Correct Answer & Explanation

. Polyethylene wear

Explanation

Mechanically assisted crevice corrosion (trunnionosis) can occur at the modular head-neck junction, particularly with large metal heads on standard trunnions. It can present with adverse local tissue reactions (ALTR) or pseudotumors despite a non-metal-on-metal articulation.

Question 3114

Topic: Total Hip Arthroplasty (THA)

A patient undergoes a posterior approach total hip arthroplasty. Postoperatively, the patient experiences recurrent anterior dislocations. Which of the following component malpositions is most likely responsible?

. Excessive acetabular anteversion
. Inadequate acetabular abduction
. Excessive femoral retroversion
. Inadequate femoral offset
. Excessive acetabular retroversion

Correct Answer & Explanation

. Excessive acetabular anteversion

Explanation

Anterior hip dislocations after THA are typically caused by excessive combined anteversion, which includes excessive acetabular anteversion or excessive femoral anteversion. Excessive retroversion typically predisposes a patient to posterior dislocation.

Question 3115

Topic: 3. Adult Reconstruction (Hip & Knee)



A 68-year-old male sustains a basicervical femoral neck fracture. Which of the following fixation methods is most appropriate due to the inherent biomechanical instability of this specific fracture pattern?

. Three parallel cannulated screws
. Sliding hip screw with an anti-rotation screw
. Hemiarthroplasty
. Total hip arthroplasty
. Proximal femoral locking plate

Correct Answer & Explanation

. Three parallel cannulated screws

Explanation

Basicervical femoral neck fractures are considered rotationally and axially unstable, behaving more like extracapsular intertrochanteric fractures. A sliding hip screw (often with a derotation screw) or a cephalomedullary nail provides superior fixation compared to multiple cannulated screws.

Question 3116

Topic: 3. Adult Reconstruction (Hip & Knee)

Following a total hip arthroplasty, a patient has a completely stable hip but complains that the operative leg feels 1.5 cm longer. Intraoperative templating was accurate. Which of the following adjustments during surgery would have corrected this leg length discrepancy without compromising abductor tension?

. Increasing the femoral head neck length
. Decreasing the femoral neck offset and increasing neck length
. Increasing the depth of acetabular reaming and lowering the neck cut
. Using a high-offset femoral stem and a shorter femoral head
. Lateralizing the acetabular cup

Correct Answer & Explanation

. Increasing the femoral head neck length

Explanation

To decrease leg length while maintaining abductor tension (offset), the surgeon should use a shorter femoral head (to drop leg length) while simultaneously using a high-offset stem to restore the horizontal distance. This prevents postoperative abductor laxity and instability.

Question 3117

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old man with a history of ankylosing spondylitis is scheduled for a bilateral total hip arthroplasty. To prevent heterotopic ossification, which of the following prophylactic regimens is most appropriate?

. Single-dose radiation therapy (700-800 cGy) within 24 hours postoperatively
. Oral indomethacin for 3 days postoperatively
. Intravenous dexamethasone for 5 days postoperatively
. Subcutaneous low-molecular-weight heparin for 4 weeks
. Oral bisphosphonates for 6 months preoperatively

Correct Answer & Explanation

. Single-dose radiation therapy (700-800 cGy) within 24 hours postoperatively

Explanation

Patients with ankylosing spondylitis are at high risk for heterotopic ossification (HO) following THA. Prophylaxis with single-fraction localized radiation therapy (700-800 cGy) within 24-48 hours postoperatively or oral indomethacin for 2 to 6 weeks is highly effective in preventing HO.

Question 3118

Topic: 3. Adult Reconstruction (Hip & Knee)



A 75-year-old woman sustains a fall. Radiographs show a valgus-impacted femoral neck fracture (Garden I). She is currently ambulating with minimal pain. What is the recommended treatment?

. Non-weight bearing conservative management for 6 weeks
. In situ fixation with multiple cannulated screws
. Bipolar hemiarthroplasty
. Total hip arthroplasty
. Proximal femoral replacement

Correct Answer & Explanation

. Non-weight bearing conservative management for 6 weeks

Explanation

Garden I (valgus-impacted) femoral neck fractures have a high risk of secondary displacement if treated conservatively. In situ fixation with parallel cannulated screws is the standard of care to prevent displacement and promote healing, even in the elderly.

Question 3119

Topic: Total Hip Arthroplasty (THA)

A 42-year-old active male underwent a ceramic-on-ceramic total hip arthroplasty 3 years ago. He presents with an audible 'squeaking' noise from the hip during deep flexion, though he denies any pain. Radiographs show no loosening. What is the most common factor associated with this phenomenon?

. Femoral stem subsidence
. Subclinical deep infection
. Component malposition causing edge loading
. Fracture of the ceramic liner
. Trunnionosis at the head-neck junction

Correct Answer & Explanation

. Femoral stem subsidence

Explanation

Squeaking is a known complication of ceramic-on-ceramic bearings. It is most strongly associated with component malposition (e.g., steep acetabular cup angle or excessive anteversion), which leads to edge loading, loss of fluid film lubrication, and stripe wear.

Question 3120

Topic: 3. Adult Reconstruction (Hip & Knee)

A 77-year-old woman who underwent a cemented total hip arthroplasty 10 years ago now reports groin pain. Examination reveals a loosened acetabular component and a well-fixed femoral component. Treatment should consist of revision of

. the acetabular component only using a cemented implant.
. the acetabular component only using a cementless implant.
. both components using cemented implants.
. both components using cementless implants.
. the acetabular component using a cementless implant and revision of the femoral component using a cemented implant.

Correct Answer & Explanation

. the acetabular component only using a cemented implant.

Explanation

Recent literature supports retention of well-fixed cemented femoral components when revising loosened cemented acetabular components. Current literature also supports the use of cementless components for revision of loosened cemented acetabular components. Peters CL, Kull L, Jacobs JJ, Rosenberg AG, Galante JO: The fate of well fixed cemented femoral components left in place at the time of revision of the acetabular component. J Bone Joint Surg Am 1997;79:701-706. Poon ED, Lachiewicz PF: Results of isolated acetabular revisions: The fate of the unrevised femoral component. J Arthroplasty 1998;13:42-49. Moskal JT, Shen FH, Brown TE: The fate of stable femoral components retained during isolated acetabular revision: A six- to twelve-year follow-up study. J Bone Joint Surg Am 2002;84:250-255.

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