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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 206 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 4101

Topic: 3. Adult Reconstruction (Hip & Knee)

A 58-year-old male complains of severe mechanical hip pain 6 months following a primary THA utilizing a dual mobility construct. Radiographs show eccentric seating of the inner cobalt-chromium head within the polyethylene liner. What complication has uniquely occurred in this specific implant design?

. Intra-prosthetic dislocation (IPD)
. Polyethylene wear-through due to third-body debris
. Dissociation of the modular titanium neck
. Acetabular component spinout
. Trunnionosis with ALVAL

Correct Answer & Explanation

. Intra-prosthetic dislocation (IPD)

Explanation

Intra-prosthetic dislocation (IPD) is a complication unique to dual mobility bearings, where the inner metal head escapes the mobile polyethylene liner. It classically presents with eccentric positioning of the head on radiographs and requires revision.

Question 4102

Topic: Total Hip Arthroplasty (THA)



A 42-year-old male with a history of severe traumatic brain injury requires a THA for post-traumatic hip osteoarthritis. Radiographs preoperatively demonstrate massive heterotopic ossification (Brooker Class IV) bridging the joint. Following resection and THA, what is the most appropriate prophylaxis to prevent recurrence?

. Oral bisphosphonates for 6 months
. Single-fraction localized external beam radiation therapy (700 cGy) postoperatively
. Intravenous corticosteroids for 48 hours postoperatively
. Continuous passive motion (CPM) machine for 4 weeks
. High-dose oral calcium channel blockers

Correct Answer & Explanation

. Single-fraction localized external beam radiation therapy (700 cGy) postoperatively

Explanation

Patients with prior severe heterotopic ossification, especially with neurogenic risk factors, are at very high risk for recurrence. Prophylaxis with single-dose localized radiation (given preop or within 72 hours postop) or oral NSAIDs (like Indomethacin) is the standard of care.

Question 4103

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the 2018 International Consensus Meeting (ICM) criteria, which of the following is considered a 'major criterion' that definitively confirms the diagnosis of periprosthetic joint infection?

. A single positive intraoperative tissue culture
. Elevated serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
. Positive synovial fluid alpha-defensin
. Two positive periprosthetic cultures with phenotypically identical organisms
. Purulence in the joint noted by the surgeon during arthrotomy

Correct Answer & Explanation

. Two positive periprosthetic cultures with phenotypically identical organisms

Explanation

The 2018 ICM criteria define two major criteria for definitive PJI: (1) a sinus tract communicating with the joint, or (2) two positive periprosthetic cultures of the exact same organism. Elevated inflammatory markers and alpha-defensin are minor criteria.

Question 4104

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old female presents with groin pain 5 years after a metal-on-metal total hip arthroplasty. Metal ion levels are elevated. MRI with MARS reveals a cystic mass communicating with the joint space. What is the most likely predominant histologic finding of the periarticular tissue?

. Intense neutrophilic infiltrate
. Extensive macrophage infiltrate with intracellular polyethylene debris
. Perivascular lymphocytic infiltrate and tissue necrosis
. Benign multinucleated giant cells with woven bone formation
. Malignant spindle cells with high mitotic index

Correct Answer & Explanation

. Perivascular lymphocytic infiltrate and tissue necrosis

Explanation

Adverse local tissue reactions (ALVAL) in metal-on-metal hips are characterized histologically by a perivascular lymphocytic infiltrate, macrophage accumulation, and tissue necrosis. Neutrophils suggest infection, while intracellular debris suggests standard polyethylene wear.

Question 4105

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male presents with a chronically painful THA. Aspiration yields synovial fluid with a white blood cell count of 4,500 cells/uL and 85% polymorphonuclear neutrophils. According to the 2018 International Consensus Meeting criteria, which of the following biomarkers would most strongly support the diagnosis of a periprosthetic joint infection?

. Elevated serum erythrocyte sedimentation rate (ESR)
. Elevated synovial fluid alpha-defensin
. Elevated serum D-dimer
. Depressed synovial fluid C-reactive protein (CRP)
. Elevated serum procalcitonin

Correct Answer & Explanation

. Elevated synovial fluid alpha-defensin

Explanation

Synovial fluid alpha-defensin is a major criterion and a highly specific biomarker for PJI in the 2018 ICM criteria. While ESR and D-dimer are useful screening tools, alpha-defensin has superior specificity and sensitivity for definitively confirming PJI.

Question 4106

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female presents with right thigh pain after a fall. She has a cementless right THA placed 10 years ago.

Assuming the radiograph shows a fracture around the tip of a loose femoral stem with poor proximal diaphyseal bone stock, what is the most appropriate surgical management?

. Open reduction internal fixation with cables and a laterally based plate
. Revision to a standard length cementless stem
. Revision to a long fully porous-coated or fluted tapered stem
. Revision with a proximal femoral replacement
. Impaction bone grafting and cementing a new standard stem

Correct Answer & Explanation

. Revision to a long fully porous-coated or fluted tapered stem

Explanation

A fracture around a loose stem with poor bone stock is classified as a Vancouver B3 periprosthetic fracture. The standard of care is revision to a diaphyseal-engaging long stem (fluted, tapered, or fully porous-coated) to bypass the deficient proximal bone.

Question 4107

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old man with a metal-on-polyethylene total hip arthroplasty presents with new-onset groin pain. Radiographs show a well-fixed construct. Blood cobalt levels are significantly higher than chromium levels. What is the most likely source of the wear debris?

. Articular bearing surface wear
. Acetabular shell back-side wear
. Trunnion-head modular junction
. Stem-cement interface fretting
. Impingement of the femoral neck on the acetabular component

Correct Answer & Explanation

. Trunnion-head modular junction

Explanation

Elevated serum cobalt levels disproportionately higher than chromium in a metal-on-polyethylene bearing strongly suggests mechanically assisted crevice corrosion. This phenomenon, known as trunnionosis, occurs at the modular head-neck junction.

Question 4108

Topic: 3. Adult Reconstruction (Hip & Knee)

A 52-year-old woman complains of an audible squeaking sound from her hip when walking up stairs, two years after receiving a ceramic-on-ceramic total hip arthroplasty. Which of the following factors is most strongly associated with this phenomenon?

. Stem subsidence
. High body mass index
. Edge loading due to cup malposition
. Subclinical periprosthetic joint infection
. Use of a 28-mm femoral head rather than a 36-mm head

Correct Answer & Explanation

. Edge loading due to cup malposition

Explanation

Squeaking in ceramic-on-ceramic THA is highly associated with edge loading, often resulting from acetabular cup malposition (excessive anteversion or inclination). This disrupts fluid film lubrication, leading to stripe wear and audible noise.

Question 4109

Topic: 3. Adult Reconstruction (Hip & Knee)
A 35-year-old patient with a history of high-dose corticosteroid use presents with severe groin pain. Radiographs show subchondral collapse (crescent sign) and early flattening of the femoral head, but the joint space is preserved. What is the most reliable definitive surgical treatment for pain relief and functional improvement?
. Core decompression with vascularized fibular graft
. Core decompression with bone marrow aspirate concentrate
. Total hip arthroplasty
. Rotational osteotomy of the proximal femur
. Arthroscopic debridement of the necrotic bone

Correct Answer & Explanation

. Total hip arthroplasty

Explanation

Once subchondral collapse (Ficat stage III) has occurred in femoral head osteonecrosis, joint-preserving procedures have unacceptably high failure rates. Total hip arthroplasty provides the most reliable pain relief and functional restoration in this setting.

Question 4110

Topic: 3. Adult Reconstruction (Hip & Knee)



During a revision total hip arthroplasty, the surgeon suspects a complete separation of the superior and inferior halves of the hemipelvis. Which of the following radiographic signs preoperatively would most strongly confirm pelvic discontinuity?

. Medial migration of the acetabular component beyond the ilioischial line
. An asymmetric teardrop sign
. A visible fracture line extending through the posterior column and a broken ischial plate
. A radiolucent line in DeLee and Charnley zone 1 only
. Superior migration of the femoral head center of rotation

Correct Answer & Explanation

. A visible fracture line extending through the posterior column and a broken ischial plate

Explanation

Pelvic discontinuity is a complete separation of the ilium from the ischium and pubis. Radiographic hallmarks include a visible transverse fracture line across the columns, medial translation of the inferior hemipelvis, and broken previously placed osteosynthesis plates.

Question 4111

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old woman sustains a periprosthetic femur fracture around a cemented total hip arthroplasty. Radiographs reveal the fracture is around the stem, the stem is loose, but the proximal femoral bone stock is adequate. What is the Vancouver classification and optimal treatment?

. Vancouver B1: ORIF with locking plates and cables
. Vancouver B2: Revision to a long, porous-coated cementless stem
. Vancouver B3: Proximal femoral replacement
. Vancouver C: ORIF with locking plates
. Vancouver A: Nonoperative management

Correct Answer & Explanation

. Vancouver B2: Revision to a long, porous-coated cementless stem

Explanation

A fracture around a loose stem with adequate proximal bone stock is a Vancouver B2 injury. The standard of care is revision arthroplasty using a long cementless stem that bypasses the fracture.

Question 4112

Topic: 3. Adult Reconstruction (Hip & Knee)
A 28-year-old male sustains a highly vertical, displaced femoral neck fracture (Pauwels III). Which fixation construct offers the most optimal biomechanical stability for this specific, high-shear fracture pattern?
. Three parallel cancellous screws
. Sliding hip screw with a derotation screw
. Standard cephalomedullary nail
. Hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. Sliding hip screw with a derotation screw

Explanation

Pauwels III fractures are characterized by a highly vertical fracture line and tremendous shear forces. A sliding hip screw with an anti-rotation screw or a fixed-angle device provides superior biomechanical stability and higher union rates compared to parallel cancellous screws alone.

Question 4113

Topic: 3. Adult Reconstruction (Hip & Knee)

An 80-year-old woman with a well-fixed cementless total hip arthroplasty sustains a fall. Radiographs demonstrate a periprosthetic femur fracture extending around the stem, but the stem remains completely stable (Vancouver B1). What is the standard operative management?

. Revision to a long-stem cemented femoral component
. Revision to a long-stem cementless diaphyseal engaging stem
. Open reduction and internal fixation utilizing locking plates and/or cerclage wires
. Non-weight bearing conservative management in a hip spica cast
. Femoral impaction grafting with retention of the stem

Correct Answer & Explanation

. Open reduction and internal fixation utilizing locking plates and/or cerclage wires

Explanation

A Vancouver B1 fracture is defined as a fracture around or just below a well-fixed femoral stem. The gold standard treatment is open reduction and internal fixation using locking plates, cerclage cables, and potentially cortical strut allografts, while retaining the stable prosthesis.

Question 4114

Topic: 3. Adult Reconstruction (Hip & Knee)

A 30-year-old male suffers a posterior hip dislocation with a posterior wall acetabular fracture. Following closed reduction, a CT scan shows a posterior wall defect involving 45% of the articular surface. What is the most appropriate treatment?

. Skeletal traction for 6 weeks
. Touch-down weight bearing for 12 weeks
. Open reduction and internal fixation
. Hip spica casting
. Immediate total hip arthroplasty

Correct Answer & Explanation

. Open reduction and internal fixation

Explanation

Indications for open reduction and internal fixation of a posterior wall acetabular fracture include joint instability on dynamic stress testing, an intra-articular loose body, and wall defects involving >20-40% of the posterior articular surface.

Question 4115

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female presents with a displaced supracondylar femur fracture just proximal to a well-fixed posterior-stabilized total knee arthroplasty (TKA). If retrograde intramedullary nailing is planned, which TKA design feature is the most critical to evaluate preoperatively?

. Polyethylene thickness
. Tibial tray stem length
. Intercondylar box width of the femoral component
. Patellar button thickness
. Femoral component distal radius of curvature

Correct Answer & Explanation

. Intercondylar box width of the femoral component

Explanation

In posterior-stabilized TKA designs, the closed intercondylar box restricts access to the medullary canal. The width and configuration of this box must be evaluated preoperatively to ensure a retrograde nail can pass through without impinging.

Question 4116

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old woman sustains a mechanical fall and presents with thigh pain. Radiographs reveal a spiral fracture around the tip of her cemented, polished taper-slip total hip arthroplasty stem. The stem demonstrates a 4 mm subsidence and a prominent cement mantle fracture. According to the Vancouver classification system, what is the most appropriate treatment?

. Open reduction and internal fixation with a laterally applied locking plate and strut allografts
. Revision to a long uncemented, fully porous-coated or fluted tapered diaphyseal-engaging stem
. Revision to a long cemented stem
. Nonoperative management in a hip spica cast
. Open reduction and internal fixation with cerclage cables only

Correct Answer & Explanation

. Revision to a long uncemented, fully porous-coated or fluted tapered diaphyseal-engaging stem

Explanation

This is a Vancouver B2 periprosthetic fracture, defined by a fracture around a loose femoral component with adequate remaining bone stock. The standard of care is revision arthroplasty utilizing a diaphyseal-engaging (uncemented) long stem.

Question 4117

Topic: 3. Adult Reconstruction (Hip & Knee)

The primary blood supply to the scaphoid bone enters anatomically at the:

. Volar proximal pole
. Dorsal distal pole and waist
. Volar distal pole only
. Dorsal proximal pole
. Scapholunate ligament insertion

Correct Answer & Explanation

. Dorsal proximal pole

Explanation

The primary blood supply to the scaphoid is retrograde, entering through branches of the radial artery at the dorsal ridge near the distal pole and waist. This anatomical configuration leaves the proximal pole highly susceptible to avascular necrosis after a fracture.

Question 4118

Topic: 3. Adult Reconstruction (Hip & Knee)

During ORIF of a posterior wall acetabular fracture, an area of marginal impaction of the articular cartilage is identified. What is the most appropriate management of this articular fragment?

. Excision of the impacted fragment
. Elevation of the fragment, cancellous bone grafting, and support with a plate
. Leave the fragment in situ and fix the posterior wall over it
. Primary total hip arthroplasty
. Drilling of the fragment to promote fibrocartilage formation

Correct Answer & Explanation

. Elevation of the fragment, cancellous bone grafting, and support with a plate

Explanation

Marginal impaction involves articular cartilage driven into the underlying cancellous bone. To restore joint congruity, the impacted segment must be elevated, the defect filled with bone graft, and the construct supported by posterior wall fixation.

Question 4119

Topic: 3. Adult Reconstruction (Hip & Knee)

A 25-year-old female sustains a displaced basicervical femoral neck fracture following a fall from a height. She has no other injuries. Which of the following internal fixation constructs provides the most biomechanical stability for this specific fracture pattern?

. Three cancellous cannulated screws in an inverted triangle pattern
. Cephalomedullary nailing
. Sliding hip screw with an anti-rotation screw
. Bipolar hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation screw

Explanation

Basicervical femoral neck fractures are biomechanically distinct, length-unstable, and have a higher rate of failure when fixed with multiple cannulated screws alone. A sliding hip screw, often supplemented with a derotational screw, provides superior biomechanical stability and is the gold standard for this fracture pattern.

Question 4120

Topic: Total Hip Arthroplasty (THA)

During a posterior approach for a TLIF at L4-L5, a pedicle screw is being placed into the right L4 vertebra. A medial breach of the pedicle wall occurs. Which neural structure is at greatest risk of iatrogenic injury?

. The exiting L3 nerve root
. The exiting L4 nerve root
. The traversing L4 nerve root
. The traversing L5 nerve root
. The sympathetic chain

Correct Answer & Explanation

. The traversing L5 nerve root

Explanation

A medial breach of the lumbar pedicle endangers the traversing nerve root of that same level (the L4 root at the L4 pedicle). An inferior pedicle breach, conversely, risks the exiting nerve root of that level (the L4 exiting root).

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