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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 201 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 4001

Topic: 3. Adult Reconstruction (Hip & Knee)



A 78-year-old man falls and sustains an unstable intertrochanteric femur fracture. Pre-injury radiographs demonstrate severe bone-on-bone osteoarthritis of the ipsilateral hip. What is the most appropriate definitive management?

. Sliding hip screw fixation
. Cephalomedullary nail fixation
. Bipolar hemiarthroplasty
. Total hip arthroplasty using a specialized stem
. Nonoperative management

Correct Answer & Explanation

. Total hip arthroplasty using a specialized stem

Explanation

In an elderly patient with an intertrochanteric fracture and pre-existing severe symptomatic hip osteoarthritis, a total hip arthroplasty (often using a long calcar-replacing or diaphyseal-fitting stem) addresses both the fracture and the arthritis concurrently.

Question 4002

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old woman sustains a fall 5 years after an uncemented total hip arthroplasty.

Radiographs show a fracture around the stem. Intraoperatively, the stem is found to be loose, but the surrounding bone stock is adequate. What is the most appropriate management according to the Vancouver classification?

. Open reduction and internal fixation with cerclage wiring
. Open reduction and internal fixation with a locking plate
. Revision to a long uncemented diaphyseal-engaging stem
. Revision to a standard length cemented stem
. Distal femoral replacement

Correct Answer & Explanation

. Revision to a long uncemented diaphyseal-engaging stem

Explanation

This is a Vancouver B2 periprosthetic fracture, characterized by a fracture around a loose stem with adequate bone stock. The gold standard treatment is revision to a long uncemented extensively porous-coated or fluted tapered stem that bypasses the fracture.

Question 4003

Topic: 3. Adult Reconstruction (Hip & Knee)

A 58-year-old man with a metal-on-metal total hip arthroplasty presents with progressive groin pain.

Serum cobalt and chromium levels are elevated. MRI with MARS shows a large cystic fluid collection compressing the femoral nerve. What is the most appropriate surgical management?

. Isolated exchange of the femoral head
. Irrigation and debridement with retention of hardware
. Revision to a non-metal bearing surface with extensive synovectomy
. Revision of the acetabular component only
. Percutaneous aspiration of the fluid collection

Correct Answer & Explanation

. Revision to a non-metal bearing surface with extensive synovectomy

Explanation

Symptomatic adverse local tissue reactions (ALTR) or pseudotumors in MoM hips require operative intervention. The standard management is revision of the bearing surfaces to non-metal options (e.g., ceramic-on-polyethylene) accompanied by an extensive synovectomy.

Question 4004

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old man presents with progressive groin pain 6 years after a metal-on-polyethylene total hip arthroplasty.

His infection workup is negative. Serum cobalt levels are significantly elevated, while chromium levels are normal. What is the most likely etiology of his symptoms?

. Bearing surface wear
. Trunnionosis (mechanically assisted crevice corrosion)
. Occult periprosthetic joint infection
. Aseptic loosening of the acetabular component
. Iliopsoas impingement

Correct Answer & Explanation

. Trunnionosis (mechanically assisted crevice corrosion)

Explanation

Disproportionately elevated serum cobalt levels compared to chromium in a patient with a metal-on-polyethylene THA is highly suggestive of trunnionosis. This mechanically assisted crevice corrosion occurs at the modular head-neck junction.

Question 4005

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old woman with severe bilateral hip dysplasia presents for primary total hip arthroplasty.

Preoperative imaging reveals the femoral head is completely dislocated superiorly and articulates with a false acetabulum on the ilium (Crowe IV). During surgery to restore the true anatomic hip center, which complication is she at highest risk for?

. Sciatic nerve palsy
. Femoral artery pseudoaneurysm
. Obturator nerve palsy
. Superior gluteal artery injury
. Pudendal nerve palsy

Correct Answer & Explanation

. Sciatic nerve palsy

Explanation

In Crowe IV hip dysplasia, restoring the anatomic hip center requires significant distal translation (lengthening) of the femur. This acute lengthening places the sciatic nerve at a high risk for stretch palsy.

Question 4006

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old female experiences a posterior dislocation of her total hip arthroplasty 3 weeks postoperatively.

Radiographs show no fractures, and the components are deemed to be in the "safe zone" for anteversion and inclination. What is the most appropriate initial management?

. Immediate revision THA with a constrained liner
. Closed reduction and hip abduction bracing
. Closed reduction and immediate weight bearing as tolerated
. Open reduction and internal fixation of the greater trochanter
. Revision of the femoral head to increase neck length

Correct Answer & Explanation

. Closed reduction and hip abduction bracing

Explanation

For a first-time, early postoperative posterior THA dislocation with optimally positioned components, the standard of care is closed reduction. This is typically followed by a period of hip abduction bracing to allow the posterior soft tissues to heal.

Question 4007

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old woman requires a revision total hip arthroplasty for massive aseptic loosening.

CT imaging demonstrates a transverse fracture through the acetabulum with complete separation of the superior and inferior hemipelvis. What is the most reliable construct to manage this defect?

. Standard hemispherical uncemented cup with multiple screws
. Jumbo uncemented cup without adjunctive fixation
. Cup-cage construct or custom triflange component
. Cemented all-polyethylene cup
. Impaction bone grafting with a standard cemented cup

Correct Answer & Explanation

. Cup-cage construct or custom triflange component

Explanation

The patient has pelvic discontinuity, which requires rigid mechanical stabilization between the superior and inferior hemipelvis to achieve fixation. A cup-cage construct, custom triflange, or a distraction technique with highly porous metal are the preferred treatments.

Question 4008

Topic: 3. Adult Reconstruction (Hip & Knee)

Historically, Lewinnek described a "safe zone" for acetabular cup positioning in primary total hip arthroplasty to minimize the risk of dislocation. Which of the following defines this classic zone?

. 30° ± 10° inclination and 10° ± 10° anteversion
. 40° ± 10° inclination and 15° ± 10° anteversion
. 45° ± 10° inclination and 25° ± 10° anteversion
. 50° ± 10° inclination and 15° ± 10° anteversion
. 40° ± 10° inclination and 5° ± 10° anteversion

Correct Answer & Explanation

. 40° ± 10° inclination and 15° ± 10° anteversion

Explanation

The classic Lewinnek safe zone for the acetabular component in THA is 40° ± 10° of inclination (abduction) and 15° ± 10° of anteversion. Placement outside this zone was historically thought to dramatically increase dislocation risk, though modern studies suggest individual spinopelvic kinematics play a larger role.

Question 4009

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old woman presents with lateral hip pain and a severe, unremitting Trendelenburg gait 18 months after a total hip arthroplasty via a direct lateral (Hardinge) approach.

MRI confirms a massive, retracted tear of the gluteus medius and minimus tendons with fatty infiltration. What is the most appropriate surgical management?

. Direct primary repair with nonabsorbable suture
. Trochanteric advancement
. Gluteus maximus muscle flap transfer
. Revision to a constrained liner
. Endoscopic bursectomy and debridement

Correct Answer & Explanation

. Gluteus maximus muscle flap transfer

Explanation

For chronic, massive, retracted abductor tendon tears following a lateral approach where primary repair is not feasible, a gluteus maximus or vastus lateralis muscle flap transfer is the most appropriate procedure. This restores abductor tension and improves the Trendelenburg gait.

Question 4010

Topic: Total Hip Arthroplasty (THA)

A 45-year-old active man underwent a total hip arthroplasty with a ceramic-on-ceramic bearing 3 years ago. He now complains of a squeaking noise during walking. Radiographs show a well-fixed stem and an acetabular component abducted to 60 degrees. What is the most likely cause of this phenomenon?

. Stripe wear from edge loading
. Impingement of the psoas tendon
. Third-body wear from retained cement
. Fatigue failure of the ceramic head
. Trunnionosis at the head-neck junction

Correct Answer & Explanation

. Stripe wear from edge loading

Explanation

Squeaking in ceramic-on-ceramic THA is highly associated with edge loading caused by component malposition, particularly a steeply placed acetabular cup. Edge loading disrupts the fluid film lubrication, leading to stripe wear and the characteristic squeaking sound.

Question 4011

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old woman presents with persistent groin pain 4 years after a primary metal-on-polyethylene total hip arthroplasty using a large-diameter cobalt-chromium head. Inflammatory markers are normal, and aspiration is negative for infection. Serum cobalt levels are significantly elevated compared to chromium. What is the most likely diagnosis?

. Metallosis from bearing wear
. Trunnionosis at the head-neck junction
. Polyethylene wear-induced osteolysis
. Aseptic loosening of the acetabular cup
. Iliopsoas impingement

Correct Answer & Explanation

. Trunnionosis at the head-neck junction

Explanation

Trunnionosis, or mechanically assisted crevice corrosion at the modular head-neck junction, can occur in metal-on-polyethylene THAs, particularly those with large CoCr heads. It typically presents with groin pain, normal inflammatory markers, and a disproportionate elevation of serum cobalt over chromium.

Question 4012

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old man reports a 6-month history of groin pain 2 years following a total hip arthroplasty. The pain is primarily exacerbated by active straight-leg raising and getting out of a car. A cross-table lateral radiograph reveals the acetabular component is proud anteriorly. What is the most appropriate initial management?

. Revision of the acetabular component
. Iliopsoas tenotomy
. Diagnostic and therapeutic image-guided corticosteroid injection
. Oral bisphosphonates
. Revision to a dual mobility bearing

Correct Answer & Explanation

. Diagnostic and therapeutic image-guided corticosteroid injection

Explanation

The clinical presentation is classic for iliopsoas impingement against a prominent anterior acetabular rim. Initial management should consist of an image-guided diagnostic and therapeutic local anesthetic/corticosteroid injection, followed by physical therapy.

Question 4013

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following biologic pathways is the primary driver of osteolysis secondary to polyethylene wear debris in total hip arthroplasty?

. T-cell mediated delayed hypersensitivity response
. Macrophage phagocytosis of submicron particles leading to RANKL expression
. Direct toxicity of polyethylene ions to osteoblasts
. Complement cascade activation by polymorphonuclear leukocytes
. Antibody-antigen complex deposition in the periprosthetic tissue

Correct Answer & Explanation

. Macrophage phagocytosis of submicron particles leading to RANKL expression

Explanation

Polyethylene wear debris generates submicron particles that are phagocytosed by macrophages. This activates the macrophages to release cytokines (TNF-alpha, IL-1, IL-6), which subsequently stimulate RANKL expression and osteoclastic bone resorption.

Question 4014

Topic: 3. Adult Reconstruction (Hip & Knee)

When highly cross-linked polyethylene (HXLPE) is used in total hip arthroplasty to reduce volumetric wear, which of the following material properties is subsequently decreased compared to conventional polyethylene?

. Oxidation resistance
. Elastic modulus
. Fatigue strength and fracture toughness
. Melting point
. Biocompatibility

Correct Answer & Explanation

. Fatigue strength and fracture toughness

Explanation

While high levels of radiation cross-linking significantly improve the wear resistance of polyethylene, it inversely affects certain mechanical properties. This alteration results in decreased fatigue strength, tensile strength, and fracture toughness.

Question 4015

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old patient with Parkinson's disease is scheduled for a revision total hip arthroplasty for recurrent instability. The surgeon decides to use a dual mobility construct. What complication is unique to this specific bearing design?

. Aseptic loosening of the femoral stem
. Intraprosthetic dislocation
. Accelerated polyethylene volumetric wear
. Trunnionosis
. Squeaking

Correct Answer & Explanation

. Intraprosthetic dislocation

Explanation

Intraprosthetic dislocation is a complication unique to dual mobility bearings. It occurs when the polyethylene liner disengages from the smaller, captive metallic or ceramic inner femoral head, often requiring revision surgery.

Question 4016

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old woman sustains a fall 5 years after a cementless total hip arthroplasty. Radiographs reveal a periprosthetic femur fracture extending around the distal tip of the stem. The stem is visibly subsided, but the proximal femoral bone stock is adequate. According to the Vancouver classification, what is the most appropriate surgical treatment?

. Open reduction and internal fixation with a locking plate alone
. Open reduction and internal fixation with cortical strut allografts alone
. Revision to a standard length cemented stem
. Revision to a longer cementless extensively porous-coated stem bypassing the fracture
. Proximal femoral replacement

Correct Answer & Explanation

. Revision to a longer cementless extensively porous-coated stem bypassing the fracture

Explanation

This describes a Vancouver B2 periprosthetic fracture, characterized by a fracture around the stem with a loose implant but adequate host bone stock. The standard of care is revision of the loose component using a longer, extensively porous-coated or fluted tapered stem that bypasses the fracture.

Question 4017

Topic: 3. Adult Reconstruction (Hip & Knee)

In primary total hip arthroplasty, increasing the femoral head diameter from 28 mm to 36 mm primarily improves joint stability by altering which of the following biomechanical parameters?

. Increasing the abductor moment arm
. Decreasing the femoral head-neck offset
. Increasing the jump distance
. Decreasing the combined anteversion
. Increasing the impingement-free range of motion solely by changing the cup position

Correct Answer & Explanation

. Increasing the jump distance

Explanation

Increasing the femoral head diameter improves stability primarily by increasing the 'jump distance,' which is the distance the head must travel to dislocate from the acetabulum. It also safely increases the impingement-free range of motion.

Question 4018

Topic: Total Hip Arthroplasty (THA)
During an acetabular revision for a failed total hip arthroplasty, the surgeon encounters severe superior migration of the hip center (>3 cm) and destruction of the teardrop, with less than 50% of the host bone available for cup contact. The Kohler line remains intact. Which of the following Paprosky defect classifications does this represent?
. Paprosky IIA
. Paprosky IIB
. Paprosky IIIA
. Paprosky IIIB
. Paprosky IV

Correct Answer & Explanation

. Paprosky IIIA

Explanation

A Paprosky IIIA defect is characterized by severe bone loss (>3 cm superior migration), destruction of the teardrop, and <50% host bone contact, but with an intact Kohler line indicating no severe medial migration. Paprosky IIIB defects, by contrast, feature severe medial migration crossing Kohler's line or pelvic discontinuity.

Question 4019

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old man with a metal-on-metal total hip arthroplasty presents with a large soft tissue mass around the hip and normal inflammatory markers. Histological examination of the periprosthetic tissue is most likely to show which of the following?

. Sheets of polymorphonuclear neutrophils
. Granulomatous inflammation with birefringent particles
. Aseptic lymphocytic vasculitis-associated lesions (ALVAL)
. Extensive woven bone formation
. Malignant spindle cells with high mitotic index

Correct Answer & Explanation

. Aseptic lymphocytic vasculitis-associated lesions (ALVAL)

Explanation

Adverse local tissue reactions (ALTR) or pseudotumors in metal-on-metal hips are characterized histologically by Aseptic Lymphocytic Vasculitis-Associated Lesions (ALVAL). This histology represents a delayed type IV hypersensitivity reaction to metal ions.

Question 4020

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old woman presents with persistent groin pain two years after undergoing an uncomplicated cementless total hip arthroplasty. Radiographs show a well-fixed acetabular component with an overhanging anterior edge. An injection of local anesthetic into the hip joint does not relieve her pain, but an injection into the psoas sheath provides complete relief. What is the most appropriate next step in management?

. Revision of the femoral component
. Arthroscopic or open iliopsoas tendon release
. Revision of the acetabular component
. Core decompression of the femoral head
. Two-stage revision for infection

Correct Answer & Explanation

. Arthroscopic or open iliopsoas tendon release

Explanation

Anterior overhang of the acetabular component can cause iliopsoas impingement. If conservative measures fail and a diagnostic injection confirms the source, iliopsoas release is the treatment of choice before considering cup revision.

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