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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 259 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 5161

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old woman with a cemented total hip arthroplasty placed 10 years ago sustains a mechanical fall. Radiographs demonstrate a displaced spiral fracture of the femur occurring entirely distal to the tip of her well-fixed femoral stem. According to the Vancouver classification, how is this fracture categorized?

. Vancouver Type A
. Vancouver Type B1
. Vancouver Type B2
. Vancouver Type C
. Vancouver Type B3

Correct Answer & Explanation

. Vancouver Type A

Explanation

The Vancouver classification for periprosthetic hip fractures is based on location and stem stability. Type A is in the trochanteric region. Type B fractures are around or just below the stem (B1 = well fixed, B2 = loose, B3 = loose with poor bone stock). Type C fractures occur well below the tip of the femoral stem. Since this fracture is entirely distal to the stem, it is a Vancouver Type C.

Question 5162

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old female presents with a periprosthetic femur fracture around a cemented polished taper slip hip stem. Radiographs show a fracture around the tip of the stem. The stem is loose, but the bone stock is adequate. What is the Vancouver classification and appropriate treatment?

. Vancouver B1; ORIF with locking plate and cables
. Vancouver B2; Revision to a long uncemented diaphyseal-fitting stem
. Vancouver B3; Revision with proximal femoral replacement
. Vancouver C; ORIF with locking plate
. Vancouver A; Nonoperative management

Correct Answer & Explanation

. Vancouver B1; ORIF with locking plate and cables

Explanation

Vancouver B2 fractures occur around the stem with a loose implant but adequate bone stock. The standard treatment is revision arthroplasty using a long uncemented diaphyseal-engaging stem (often modular), bypassing the fracture site by at least 2 cortical diameters.

Question 5163

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male with end-stage ankle osteoarthritis is being evaluated for a Total Ankle Arthroplasty (TAA). Which of the following represents an absolute contraindication to performing a TAA rather than an ankle arthrodesis in this patient?

. Age greater than 65 years
. Concomitant subtalar arthritis
. Avascular necrosis involving more than 50% of the talar body
. Coronal plane deformity of 5 degrees
. History of a healed medial malleolus fracture

Correct Answer & Explanation

. Age greater than 65 years

Explanation

Extensive avascular necrosis of the talar body (>50%) is an absolute contraindication for Total Ankle Arthroplasty due to the high risk of catastrophic implant subsidence and failure. In such cases, arthrodesis (often tibiotalocalcaneal) is preferred.

Question 5164

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old female with end-stage post-traumatic ankle osteoarthritis is being evaluated for a total ankle arthroplasty (TAA). Which of the following conditions represents an absolute contraindication to performing a TAA in this patient?

. Patient age greater than 65 years
. Prior open reduction and internal fixation of the ankle
. Charcot neuroarthropathy with loss of protective sensation
. Mild coronal plane deformity (7 degrees of valgus)
. Body mass index of 28

Correct Answer & Explanation

. Patient age greater than 65 years

Explanation

Charcot neuroarthropathy, active infection, avascular necrosis of the talar body, and severe uncorrectable malalignment are absolute contraindications for Total Ankle Arthroplasty (TAA). Loss of protective sensation leads to rapid catastrophic implant failure.

Question 5165

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old female presents with persistent anterior knee pain and feelings of instability when rising from a chair 18 months after a primary total knee arthroplasty. On exam, she has a stable knee in extension, but a lateral patellar tilt and apprehension on patellar translation. A CT scan evaluation of component rotation is performed.

Internal rotation of the femoral component in a TKA is most likely to cause which of the following biomechanical consequences?

. Increased flexion gap and lateral patellar maltracking
. Tight medial flexion gap and lateral patellar maltracking
. Medial patellar maltracking and varus instability in flexion
. Increased extension gap and anterior knee pain
. Patellar clunk syndrome

Correct Answer & Explanation

. Increased flexion gap and lateral patellar maltracking

Explanation

Internal rotation of the femoral component in TKA effectively closes down the medial flexion gap (making it tight) and increases the lateral flexion gap. Because the trochlear groove is also rotated internally, it forces the patella laterally, causing lateral patellar maltracking and potential subluxation, alongside flexion instability.

Question 5166

Topic: 3. Adult Reconstruction (Hip & Knee)

A 76-year-old female sustains a fall 5 years following an uncemented total hip arthroplasty. Radiographs reveal a periprosthetic femur fracture extending around the stem. The stem is clinically loose.

There is severe proximal bone loss with diaphyseal bone remaining intact. According to the Vancouver classification, this fracture is best classified as:

. Vancouver B1
. Vancouver B2
. Vancouver B3
. Vancouver C
. Vancouver Ag

Correct Answer & Explanation

. Vancouver B1

Explanation

The Vancouver classification for periprosthetic femur fractures relies on fracture location, implant stability, and bone stock. A fracture around the stem (Type B) with a loose stem and severe proximal bone loss is classified as Vancouver B3. Treatment typically requires bypassing the defect with a long revision stem (often a modular, fluted, tapered stem) or utilizing a proximal femoral replacement.

Question 5167

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty, after the bony resections have been made, the trial components are placed. The knee is found to be tight in extension but perfectly balanced in flexion. What is the most appropriate next step in management to balance the knee?

. Recut the distal femur to remove more bone
. Downsize the femoral component
. Resect more proximal tibia
. Release the posterior capsule
. Release the PCL

Correct Answer & Explanation

. Recut the distal femur to remove more bone

Explanation

A tight extension gap with a balanced flexion gap indicates that the problem lies solely with the extension space. The distal femoral cut affects only the extension gap. Therefore, recutting the distal femur (taking more bone) will enlarge the extension gap without changing the flexion gap. Resecting more proximal tibia would inappropriately enlarge both gaps.

Question 5168

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male presents 8 years after a primary metal-on-polyethylene total hip arthroplasty with an uncemented titanium stem and a large cobalt-chromium head. He complains of deep groin pain. Radiographs show a well-fixed stem and cup. Serum labs show elevated cobalt levels with normal chromium levels. An MRI with metal artifact reduction sequence (MARS) shows a large cystic fluid collection around the hip. What is the most likely diagnosis?

. Ceramic liner fracture
. Polyethylene wear and osteolysis
. Adverse local tissue reaction (ALTR) due to mechanically assisted crevice corrosion
. Periprosthetic joint infection
. Iliopsoas impingement

Correct Answer & Explanation

. Ceramic liner fracture

Explanation

Elevated cobalt levels out of proportion to chromium in a metal-on-polyethylene THA is highly suggestive of trunnionosis—mechanically assisted crevice corrosion at the modular head-neck junction. This can lead to an adverse local tissue reaction (ALTR) or pseudotumor, which is visible on a MARS MRI as a complex cystic or solid soft tissue mass.

Question 5169

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male presents with isolated medial compartment osteoarthritis of the knee. He is being evaluated for a medial unicompartmental knee arthroplasty (UKA). Which of the following is considered a classic absolute contraindication to a medial UKA?

. Age less than 60 years
. BMI greater than 30
. Intact ACL but deficient PCL
. Inflammatory arthropathy
. Asymptomatic patellofemoral osteoarthritis

Correct Answer & Explanation

. Age less than 60 years

Explanation

Absolute contraindications for unicompartmental knee arthroplasty (UKA) classically include inflammatory arthropathy (e.g., rheumatoid arthritis), prior complete meniscectomy in the contralateral compartment, and ACL deficiency. Age, obesity, and mild patellofemoral osteoarthritis are increasingly considered only relative contraindications or acceptable in appropriately selected patients.

Question 5170

Topic: 3. Adult Reconstruction (Hip & Knee)

In performing a primary total knee arthroplasty on a patient with a severe, fixed valgus deformity, what is a widely accepted and safe sequence of lateral soft tissue releases to balance the knee?

. LCL, IT band, popliteus, posterolateral capsule
. IT band, posterolateral capsule, LCL, popliteus
. Popliteus, LCL, posterolateral capsule, IT band
. Posterolateral capsule, IT band, LCL, popliteus
. LCL, posterolateral capsule, popliteus, IT band

Correct Answer & Explanation

. LCL, IT band, popliteus, posterolateral capsule

Explanation

For a fixed valgus deformity in TKA, a common sequence of lateral release (often using a 'pie-crusting' technique) involves: 1) Iliotibial (IT) band (which is tight in extension), 2) Posterolateral capsule, 3) Lateral collateral ligament (LCL) (if tight in both flexion and extension), and 4) Popliteus (tight in flexion). Over-release of the popliteus and LCL can lead to severe flexion instability and should be done cautiously.

Question 5171

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old female presents with the inability to perform a straight leg raise 6 months following a primary TKA. Radiographs demonstrate a displaced patellar fracture with severe disruption of the extensor mechanism.

Assuming poor host tissue quality and inadequate remnant tissue for direct repair, what is the most reliable reconstructive option for a chronic, severe extensor mechanism disruption post-TKA?

. Primary repair with heavy non-absorbable sutures
. Hamstring autograft reconstruction
. Isolated hinged knee brace application for life
. Medial gastrocnemius rotational flap
. Reconstruction using synthetic mesh (Marlex) or whole extensor mechanism allograft

Correct Answer & Explanation

. Primary repair with heavy non-absorbable sutures

Explanation

Extensor mechanism disruption after TKA is a catastrophic complication. Primary repair has an unacceptably high failure rate. Synthetic (Marlex) mesh reconstruction and whole extensor mechanism allograft are both highly reliable reconstructive techniques for chronic disruptions with poor tissue quality. Synthetic mesh has grown in popularity due to its cost-effectiveness, lack of disease transmission risk, and durable clinical results.

Question 5172

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old female with a severe, documented allergy to nickel is scheduled to undergo a primary total knee arthroplasty. Which of the following implant material choices is the most appropriate for the femoral component to prevent a hypersensitivity reaction?

. Standard Cobalt-chromium-molybdenum alloy
. Stainless steel
. Porous Tantalum
. Oxidized zirconium
. High-nitrogen steel

Correct Answer & Explanation

. Standard Cobalt-chromium-molybdenum alloy

Explanation

Standard TKA femoral components are primarily composed of cobalt-chromium alloys, which contain trace amounts of nickel. For patients with a severe, true nickel allergy, oxidized zirconium (Oxinium) or an all-titanium femoral component is recommended. Oxidized zirconium provides the wear resistance of a ceramic with the structural integrity of a metal and does not contain nickel.

Question 5173

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old female presents 1 year after a posterior-stabilized total knee arthroplasty complaining of a painful 'catching' sensation at the anterior aspect of the knee when extending from a flexed position, typically occurring at 30 to 45 degrees of flexion. Which of the following implant design factors is most strongly associated with this specific complication?

. High flex TKA design with an extended posterior condyle
. Medial pivot TKA design
. Asymmetric deep trochlear groove of the femoral component
. High intercondylar box ratio (box width to intercondylar width)
. Posterior-stabilized femoral component with a sharp superior edge of the intercondylar box

Correct Answer & Explanation

. High flex TKA design with an extended posterior condyle

Explanation

Patellar clunk syndrome is a complication most commonly associated with posterior-stabilized (PS) total knee arthroplasties. It occurs when a fibrosynovial nodule forms at the superior pole of the patella and catches within the intercondylar box of the femoral component during knee extension. A sharp superior transition/edge of the intercondylar box in older PS designs strongly predisposes the patient to this condition.

Question 5174

Topic: 3. Adult Reconstruction (Hip & Knee)

During a complex revision total hip arthroplasty for aseptic loosening of an extensively porous-coated femoral stem, the surgeon performs an Extended Trochanteric Osteotomy (ETO). Which of the following muscle attachments must remain intact to the osteotomized bone fragment to maintain its viability and prevent superior migration?

. Gluteus maximus and vastus lateralis
. Gluteus medius and vastus lateralis
. Tensor fasciae latae and gluteus minimus
. Iliopsoas and rectus femoris
. Piriformis and short external rotators

Correct Answer & Explanation

. Gluteus maximus and vastus lateralis

Explanation

An Extended Trochanteric Osteotomy (ETO) involves osteotomizing the greater trochanter and the lateral aspect of the proximal femoral diaphysis. To maintain the blood supply to the fragment and to provide a dynamic tension band that resists proximal migration, the insertions of the gluteus medius proximally and the vastus lateralis distally must remain firmly attached to the bone fragment.

Question 5175

Topic: 3. Adult Reconstruction (Hip & Knee)

A 70-year-old male is undergoing a revision total knee arthroplasty for aseptic loosening. Following the removal of the tibial component, an uncontained, massive metaphyseal bone defect is noted (AORI Type 3).

Which of the following is the most appropriate management strategy for achieving stable, durable fixation in this specific tibial defect?

. Cement only without diaphyseal stems
. Standard cement technique with screw augmentation
. Modular metal block augments alone
. Highly porous metal cone or metaphyseal sleeve with a diaphyseal stem
. Impaction bone grafting without the use of a stem

Correct Answer & Explanation

. Cement only without diaphyseal stems

Explanation

The AORI classification Type 3 represents severe metaphyseal bone loss (deficient metaphysis, often uncontained), which compromises the stability of the revision component. Standard augments are insufficient for uncontained defects of this magnitude. Highly porous metal cones or metaphyseal sleeves, combined with diaphyseal stems, are the treatment of choice for providing structural support and achieving biologic metaphyseal fixation.

Question 5176

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old female presents with an audible squeaking sound from her hip that occurs during walking, 3 years following a primary total hip arthroplasty with a ceramic-on-ceramic bearing. She denies any pain. Radiographs show well-fixed components. What is the most significant risk factor associated with the development of squeaking in this type of bearing surface?

. Component malpositioning leading to edge loading (e.g., increased cup anteversion or inclination)
. Use of a 28 mm ceramic head
. Previous history of periprosthetic joint infection
. High body mass index (>35 kg/m2)
. Use of a collared titanium stem

Correct Answer & Explanation

. Component malpositioning leading to edge loading (e.g., increased cup anteversion or inclination)

Explanation

Squeaking is a known complication of ceramic-on-ceramic (CoC) bearings. The most significant risk factor is component malpositioning, particularly acetabular cup malposition (excessive inclination or anteversion). This leads to edge loading, disruption of the fluid film lubrication, and subsequent stripe wear, which alters the resonance frequency of the components and generates the squeaking sound.

Question 5177

Topic: 3. Adult Reconstruction (Hip & Knee)

Inadverent elevation of the joint line during a revision total knee arthroplasty is most likely to result directly in which of the following clinical consequences?

. Increased maximum flexion
. Decreased tension on the posterior cruciate ligament
. Excessive valgus laxity
. Patella baja and subsequent patellar impingement
. Varus thrust during gait

Correct Answer & Explanation

. Increased maximum flexion

Explanation

Elevating the joint line during TKA or revision TKA alters the kinematics of the knee. It leads to a relative patella baja (inferior placement of the patella relative to the joint line), which can cause anterior knee pain, patellar impingement against the tibial polyethylene, and decreased range of motion. It also negatively alters collateral ligament isometry.

Question 5178

Topic: Total Hip Arthroplasty (THA)

A 78-year-old female with a history of recurrent dislocations following a primary total hip arthroplasty is scheduled for revision surgery.

The surgeon decides to use a dual mobility construct. What is the defining biomechanical feature of a dual mobility articulation?

. It utilizes a constrained liner that locks the femoral head in place with a locking ring.
. It consists of a large inner metallic head that articulates with a fixed, thin polyethylene liner.
. It utilizes a mobile polyethylene liner that articulates with both a smaller inner femoral head and a highly polished metallic outer acetabular shell.
. It prevents dislocation by increasing the offset of the femoral stem without changing the center of rotation.
. It is composed entirely of cross-linked polyethylene to allow for greater jump distance.

Correct Answer & Explanation

. It utilizes a constrained liner that locks the femoral head in place with a locking ring.

Explanation

A dual mobility construct features two distinct articulations: a smaller standard femoral head that articulates within a larger, mobile polyethylene liner. This mobile liner then articulates within a highly polished, fixed metallic acetabular shell. This design maximizes the effective head size, significantly increasing the jump distance and range of motion before impingement, thereby substantially reducing the risk of dislocation.

Question 5179

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the Musculoskeletal Infection Society (MSIS) criteria, which of the following is considered a 'major' criterion, which if present, is sufficient by itself to definitively confirm a periprosthetic joint infection (PJI)?

. Elevated serum CRP (>10 mg/L) and ESR (>30 mm/hr)
. A single positive intraoperative culture of the periprosthetic tissue
. Frank purulence observed in the affected joint
. A sinus tract communicating directly with the prosthesis
. Elevated synovial fluid white blood cell count (>3,000 cells/uL)

Correct Answer & Explanation

. Elevated serum CRP (>10 mg/L) and ESR (>30 mm/hr)

Explanation

According to the MSIS criteria (and subsequent International Consensus Meetings), the presence of a sinus tract communicating with the prosthesis OR two positive periprosthetic cultures with phenotypically identical organisms are considered 'major' criteria. Either one is definitive for the diagnosis of PJI. Purulence alone is subjective and is considered a minor criterion alongside elevated inflammatory markers.

Question 5180

Topic: 3. Adult Reconstruction (Hip & Knee)

During the tibial resection of a primary total knee arthroplasty, the medial collateral ligament (MCL) is inadvertently completely transected at its mid-substance. The surgeon should immediately consider which of the following intraoperative options?

. Proceed with a standard cruciate-retaining (CR) prosthesis and place the patient in a hinged knee brace postoperatively
. Primary repair of the MCL using suture anchors and use of a standard posterior-stabilized (PS) prosthesis
. Primary repair of the MCL and use of a more constrained prosthesis, such as a constrained condylar knee (CCK)
. Proceed with a standard PS prosthesis, as the cam-post mechanism will provide adequate coronal stability
. Abort the procedure and return in 6 weeks for a two-stage reconstruction

Correct Answer & Explanation

. Proceed with a standard cruciate-retaining (CR) prosthesis and place the patient in a hinged knee brace postoperatively

Explanation

Complete transection of the MCL during a primary TKA results in severe valgus instability. Standard PS or CR implants do not provide coronal stability. Primary repair alone is prone to failure and stretching out. The most appropriate intraoperative management is primary repair of the ligament combined with an increase in the constraint of the prosthesis (e.g., Constrained Condylar Knee - CCK) to protect the repair and provide immediate coronal stability.

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