Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 163 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 3241

Topic: 3. Adult Reconstruction (Hip & Knee)

A healthy, independent 75-year-old community ambulator sustains a displaced femoral neck fracture. Which of the following is the primary advantage of total hip arthroplasty (THA) compared to bipolar hemiarthroplasty in this patient?

. Lower dislocation rate
. Lower risk of venous thromboembolism
. Decreased operative time
. Lower incidence of long-term groin pain and need for revision
. Reduced blood loss

Correct Answer & Explanation

. Lower dislocation rate

Explanation

In healthy, active elderly patients with displaced femoral neck fractures, THA provides better long-term functional outcomes and lower revision rates due to acetabular wear and groin pain compared to hemiarthroplasty.

Question 3242

Topic: 3. Adult Reconstruction (Hip & Knee)

Following a primary total hip arthroplasty via a direct lateral approach, a patient complains of a pronounced limp. Examination reveals a positive Trendelenburg sign. Which nerve is most likely injured?

. Sciatic nerve
. Femoral nerve
. Superior gluteal nerve
. Inferior gluteal nerve
. Obturator nerve

Correct Answer & Explanation

. Sciatic nerve

Explanation

The superior gluteal nerve innervates the gluteus medius and minimus. Injury during the direct lateral (Hardinge) approach, especially if splitting the gluteus medius >5 cm proximal to the greater trochanter, leads to abductor weakness and a Trendelenburg lurch.

Question 3243

Topic: 3. Adult Reconstruction (Hip & Knee)



A 55-year-old male with a metal-on-metal total hip arthroplasty presents 5 years postoperatively with vague groin pain and a palpable mass. Serum cobalt and chromium levels are elevated. MRI with MARS reveals a large cystic mass communicating with the joint. What is the most appropriate next step in management?

. Aspiration and culture of the hip joint
. Revision to a polyethylene/ceramic bearing with pseudotumor excision
. Oral antibiotic therapy for 6 weeks
. Corticosteroid injection into the mass
. Observation with serial MRIs

Correct Answer & Explanation

. Aspiration and culture of the hip joint

Explanation

The patient has an Adverse Local Tissue Reaction (ALTR/pseudotumor) secondary to metal-on-metal wear. Management involves revision to a non-metal-on-metal bearing surface and excision of the pseudotumor to prevent further tissue destruction.

Question 3244

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female sustains a fall 5 years after an uncemented THA. Radiographs show a fracture at the tip of the femoral stem. The stem is radiographically loose with subsidence. According to the Vancouver classification, what type of fracture is this and what is the standard treatment?

. Vancouver B1; ORIF with cables and a plate
. Vancouver B2; revision to a long-stem implant with ORIF
. Vancouver B3; proximal femoral replacement
. Vancouver C; ORIF with plates and screws
. Vancouver A; conservative management

Correct Answer & Explanation

. Vancouver B1; ORIF with cables and a plate

Explanation

A fracture around or just below the stem with a loose implant but adequate bone stock is a Vancouver B2 fracture. Standard treatment is revision to a longer diaphyseal-engaging stem bypassing the fracture by at least 2 cortical diameters.

Question 3245

Topic: 3. Adult Reconstruction (Hip & Knee)

The blood supply to the femoral head is a critical factor in the development of avascular necrosis following a femoral neck fracture. Which vessel provides the primary blood supply to the adult femoral head?

. Artery of the ligamentum teres
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Artery of the ligamentum teres

Explanation

The medial femoral circumflex artery (MFCA), specifically its lateral epiphyseal branches, provides the predominant blood supply to the weight-bearing dome of the adult femoral head.

Question 3246

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with increasing hip pain 3 years after a primary THA. Aspiration of the hip joint yields fluid with a WBC count of 4,500 cells/uL and 85% neutrophils. Radiographs show progressive radiolucent lines around the acetabular component. What is the most appropriate definitive management?

. 6 weeks of intravenous antibiotics
. Single-stage revision arthroplasty with cementless components
. Two-stage revision arthroplasty with an antibiotic spacer
. Irrigation and debridement with modular part exchange
. Chronic antibiotic suppression

Correct Answer & Explanation

. 6 weeks of intravenous antibiotics

Explanation

The patient has a chronic periprosthetic joint infection (symptoms > 4 weeks, high WBC > 3,000 in the late setting). The gold standard treatment in North America is a two-stage revision using an antibiotic-eluting spacer followed by delayed reimplantation.

Question 3247

Topic: Total Hip Arthroplasty (THA)

A 65-year-old patient undergoes a primary THA. Postoperatively, the acetabular component is found to have 10 degrees of anteversion and 30 degrees of inclination. The patient is at highest risk for dislocation in which of the following positions?

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

Correct Answer & Explanation

. Hip extension and external rotation

Explanation

An acetabular component with relative retroversion (10 degrees of anteversion is lower than the normal target of 15-20 degrees) predisposes the hip to posterior dislocation. Posterior dislocation typically occurs with the hip in flexion, adduction, and internal rotation.

Question 3248

Topic: 3. Adult Reconstruction (Hip & Knee)

A 58-year-old male with a metal-on-metal total hip arthroplasty presents with new-onset groin pain and a palpable mass. MRI with MARS sequencing reveals a large cystic pseudo-tumor. Which of the following serum markers is most likely elevated?

. C-reactive protein (CRP) > 100 mg/L
. Cobalt and Chromium ions
. Erythrocyte sedimentation rate (ESR)
. Titanium and Vanadium ions
. Alpha-defensin

Correct Answer & Explanation

. C-reactive protein (CRP) > 100 mg/L

Explanation

Adverse local tissue reaction (ALTR) or pseudotumor formation is commonly associated with metal-on-metal bearings. Elevated serum cobalt and chromium ion levels indicate significant bearing wear or trunnionosis.

Question 3249

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old community-dwelling male presents with groin pain 8 months after closed reduction and percutaneous pinning of a Garden II femoral neck fracture. Radiographs demonstrate nonunion with backing out of the screws and 2 cm of femoral neck shortening. What is the most appropriate management?

. Removal of hardware and valgus intertrochanteric osteotomy
. Revision internal fixation with a dynamic hip screw
. Total hip arthroplasty
. Bipolar hemiarthroplasty
. Nonoperative management with protected weight-bearing

Correct Answer & Explanation

. Removal of hardware and valgus intertrochanteric osteotomy

Explanation

In an active elderly patient with a femoral neck fracture nonunion and healthy acetabular cartilage, total hip arthroplasty provides reliable pain relief and functional restoration. Arthroplasty is preferred over osteotomy in patients over 65 due to higher failure rates of joint preservation.

Question 3250

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old female sustains a periprosthetic femur fracture 5 years after a cementless THA. Radiographs show a spiral fracture around the stem extending just distal to its tip. The femoral stem is grossly loose. There is good distal bone stock. Which of the following is the best treatment?

. Open reduction and internal fixation with cables and a laterally applied plate
. Revision to a long fully porous-coated or fluted tapered stem that bypasses the fracture by two cortical diameters
. Cortical strut allograft only
. Removal of the stem and placement of an antibiotic spacer
. Proximal femoral replacement

Correct Answer & Explanation

. Open reduction and internal fixation with cables and a laterally applied plate

Explanation

This is a Vancouver B2 fracture (fracture around the stem, loose stem, adequate bone stock). The gold standard treatment is revision arthroplasty utilizing a diaphyseal engaging stem that bypasses the most distal fracture line by at least two cortical diameters.

Question 3251

Topic: Total Hip Arthroplasty (THA)

Following a right total hip arthroplasty, a patient complains of a prominent right-sided limp. Clinical exam shows the right leg is 2 cm longer than the left, and the shuck test demonstrates excessive soft tissue tension. How does increased femoral offset during THA affect hip biomechanics?

. Decreases abductor tension and increases joint reactive forces
. Increases abductor tension and decreases joint reactive forces
. Increases both abductor tension and joint reactive forces
. Decreases both abductor tension and joint reactive forces
. Has no effect on abductor tension but increases range of motion

Correct Answer & Explanation

. Decreases abductor tension and increases joint reactive forces

Explanation

Increasing femoral offset increases the lever arm of the abductor muscles. This improves abductor tension and efficiency, which subsequently decreases the overall joint reactive force across the hip joint.

Question 3252

Topic: 3. Adult Reconstruction (Hip & Knee)

In an otherwise well-functioning cementless THA with a conventional ultra-high-molecular-weight polyethylene (UHMWPE) liner, osteolysis is typically initiated by particles of what specific size?

. < 0.1 micrometers
. 0.1 to 1.0 micrometers
. 5 to 10 micrometers
. 10 to 50 micrometers
. > 50 micrometers

Correct Answer & Explanation

. < 0.1 micrometers

Explanation

Polyethylene wear particles in the submicron range, specifically between 0.1 and 1.0 micrometers, are most efficiently phagocytosed by macrophages. This initiates the inflammatory cascade that leads to osteolysis.

Question 3253

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old female with severe Alzheimer's dementia sustains a displaced femoral neck fracture. She was a limited household ambulator prior to the injury. Which of the following surgical options is associated with the lowest risk of dislocation in this specific patient?

. Total hip arthroplasty via posterior approach
. Unipolar or bipolar hemiarthroplasty via anterolateral approach
. Closed reduction and percutaneous pinning
. Open reduction and internal fixation with a dynamic hip screw
. Girdlestone resection arthroplasty

Correct Answer & Explanation

. Total hip arthroplasty via posterior approach

Explanation

In severe dementia patients who are low-demand ambulators, hemiarthroplasty is preferred over THA due to lower dislocation rates. The anterolateral approach further reduces the dislocation risk compared to the posterior approach.

Question 3254

Topic: Total Hip Arthroplasty (THA)

A 62-year-old male with a metal-on-polyethylene THA presents with painful swelling in the thigh 6 years postoperatively. Aspirate is negative for infection, but serum cobalt levels are significantly elevated. Which of the following is the most likely source of the metal debris?

. Wear of the polyethylene liner
. Corrosion at the modular head-neck taper junction
. Fretting between the acetabular shell and screws
. Galvanic corrosion between the stem and cement mantle
. Impingement of the femoral neck against the acetabular rim

Correct Answer & Explanation

. Wear of the polyethylene liner

Explanation

Elevated cobalt levels in a metal-on-polyethylene total hip arthroplasty most strongly point to mechanically assisted crevice corrosion (trunnionosis). This occurs at the modular head-neck taper junction.

Question 3255

Topic: Total Hip Arthroplasty (THA)

Following a difficult THA for developmental dysplasia of the hip, the patient develops a foot drop and is unable to actively extend the toes or dorsiflex the ankle. Sensation is intact on the plantar aspect of the foot. Which division of the sciatic nerve is most commonly injured during THA?

. Tibial division
. Peroneal division
. Sural division
. Femoral division
. Saphenous division

Correct Answer & Explanation

. Tibial division

Explanation

The peroneal (fibular) division of the sciatic nerve is more lateral and anatomically tethered at the fibular head. It possesses less protective connective tissue than the tibial division, making it highly susceptible to stretch injuries during limb lengthening in THA.

Question 3256

Topic: 3. Adult Reconstruction (Hip & Knee)

In an effort to minimize the risk of dislocation following a total hip arthroplasty, a surgeon aims to increase the 'jump distance.' Which of the following modifications will most effectively accomplish this goal?

. Decreasing the femoral head size
. Increasing the acetabular cup anteversion to 35 degrees
. Increasing the femoral head size
. Decreasing the femoral offset
. Using a short-taper femoral stem

Correct Answer & Explanation

. Decreasing the femoral head size

Explanation

Jump distance is the distance the femoral head must translate to dislocate from the acetabulum. Increasing the diameter of the femoral head directly increases the jump distance, thereby enhancing the stability of the total hip arthroplasty.

Question 3257

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with new-onset groin pain and a palpable mass 8 years after a metal-on-polyethylene total hip arthroplasty. Serum cobalt levels are significantly elevated, while chromium levels are normal. Inflammatory markers are within normal limits. What is the most likely diagnosis?

. Polyethylene wear-induced osteolysis
. Corrosion at the modular head-neck junction (trunnionosis)
. Periprosthetic joint infection
. Aseptic loosening of the acetabular cup
. Iliopsoas impingement

Correct Answer & Explanation

. Polyethylene wear-induced osteolysis

Explanation

Elevated serum cobalt levels with normal chromium in the setting of a metal-on-polyethylene bearing strongly suggests mechanically assisted crevice corrosion at the modular head-neck junction (trunnionosis), leading to an adverse local tissue reaction (ALTR).

Question 3258

Topic: 3. Adult Reconstruction (Hip & Knee)

An active, independent 78-year-old community ambulator sustains a displaced femoral neck fracture. Compared to treatment with bipolar hemiarthroplasty, treatment with total hip arthroplasty (THA) is associated with which of the following?

. Lower risk of postoperative dislocation
. Higher rate of acetabular cartilage erosion over time
. Lower reoperation rates and better long-term functional scores
. Decreased surgical time and blood loss
. Higher risk of avascular necrosis of the femoral head

Correct Answer & Explanation

. Lower risk of postoperative dislocation

Explanation

In active, independent elderly patients with displaced femoral neck fractures, THA provides superior long-term functional outcomes and lower reoperation rates compared to hemiarthroplasty, although THA carries a slightly higher initial risk of dislocation.

Question 3259

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old active male is undergoing total hip arthroplasty. Which of the following bearing surface combinations is associated with the lowest volumetric wear rate?

. Metal-on-highly cross-linked polyethylene
. Ceramic-on-highly cross-linked polyethylene
. Ceramic-on-ceramic
. Metal-on-metal
. Ceramic-on-metal

Correct Answer & Explanation

. Metal-on-highly cross-linked polyethylene

Explanation

Ceramic-on-ceramic bearing surfaces exhibit the lowest volumetric wear rates in total hip arthroplasty. However, they carry unique risks, including component fracture and squeaking.

Question 3260

Topic: 3. Adult Reconstruction (Hip & Knee)

A 35-year-old male presents with a nonunion of a femoral neck fracture 8 months after initial fixation with parallel cancellous screws. MRI confirms the femoral head remains viable with no evidence of avascular necrosis. What is the most appropriate surgical treatment?

. Valgus-producing intertrochanteric osteotomy
. Varus-producing intertrochanteric osteotomy
. Total hip arthroplasty
. Core decompression with bone marrow aspirate concentrate
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Valgus-producing intertrochanteric osteotomy

Explanation

In a young patient with a femoral neck nonunion and a viable femoral head, a valgus-producing intertrochanteric osteotomy alters the mechanical axis, converting shear forces at the fracture site into compressive forces, thereby promoting fracture healing.

Test Yourself

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

On this Page