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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 179 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 3561

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old man presents with an inability to perform an active straight leg raise 4 weeks after a primary total knee arthroplasty. Examination reveals a palpable gap at the inferior pole of the patella. What is the most reliable surgical reconstruction method for this complication?

. Primary end-to-end repair with heavy non-absorbable sutures
. Extensor mechanism allograft reconstruction
. Hamstring autograft augmentation
. Patellofemoral arthrodesis
. Gastrocnemius rotational flap

Correct Answer & Explanation

. Extensor mechanism allograft reconstruction

Explanation

Extensor mechanism disruption after TKA has a high failure rate with primary repair. Extensor mechanism allograft reconstruction (Achilles tendon or whole extensor mechanism) or synthetic mesh are preferred for reliable restoration of function.

Question 3562

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old active man with a ceramic-on-ceramic total hip arthroplasty complains of a squeaking noise during gait. Radiographs show a well-fixed implant. Which of the following component positions is most strongly associated with this phenomenon?

. Cup anteversion of 15 degrees
. Excessive cup inclination (vertical cup placement)
. Stem retroversion
. Increased femoral offset
. Cup abduction of 35 degrees

Correct Answer & Explanation

. Excessive cup inclination (vertical cup placement)

Explanation

Squeaking in ceramic-on-ceramic total hip arthroplasty is primarily associated with edge loading. This is typically caused by malpositioning of the acetabular cup, particularly excessive inclination (vertical cup) or excessive anteversion.

Question 3563

Topic: Total Knee Arthroplasty (TKA)

In kinematic alignment for a total knee arthroplasty, the surgical goal differs from traditional mechanical alignment by aiming to restore the patient's pre-arthritic joint lines. This approach typically results in which of the following component positions compared to mechanical alignment?

. More valgus femoral component and more varus tibial component
. More varus femoral component and more valgus tibial component
. Parallel joint line to the mechanical axis
. Increased external rotation of the femoral component
. Symmetrical extension gap

Correct Answer & Explanation

. More valgus femoral component and more varus tibial component

Explanation

Kinematic alignment aims to restore the native joint line, which typically involves placing the femoral component in slightly more valgus and the tibial component in slightly more varus compared to the neutral mechanical axis.

Question 3564

Topic: Total Hip Arthroplasty (THA)

A 70-year-old woman experiences multiple posterior dislocations following a primary THA via a posterior approach. A CT scan shows the acetabular component is in 5 degrees of anteversion and 40 degrees of inclination. The stem is in 15 degrees of anteversion. What is the most appropriate definitive management?

. Prescribe an abduction brace for 6 weeks
. Convert to a dual mobility articulation without changing the cup
. Revise the acetabular component to increase anteversion
. Revise the femoral stem to increase anteversion
. Advance the greater trochanter

Correct Answer & Explanation

. Revise the acetabular component to increase anteversion

Explanation

The patient has a retroverted or under-anteverted acetabular cup (5 degrees) leading to recurrent posterior instability. Revision of the acetabular component to achieve appropriate anteversion (typically 15-20 degrees) is the definitive treatment.

Question 3565

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old man presents with knee pain 2 years after a primary TKA. Joint aspiration yields a synovial WBC count of 4,500 cells/uL with 85% neutrophils. Alpha-defensin is positive, and synovial CRP is 15 mg/L. According to the 2018 International Consensus Meeting criteria, what is the diagnosis?

. Aseptic loosening
. Possible periprosthetic joint infection
. Definite periprosthetic joint infection
. Gouty arthropathy
. Adverse local tissue reaction

Correct Answer & Explanation

. Definite periprosthetic joint infection

Explanation

According to the 2018 ICM criteria, elevated synovial WBC (>3,000 cells/uL), elevated PMN% (>80%), positive alpha-defensin, and elevated synovial CRP strongly confirm the diagnosis of definite periprosthetic joint infection.

Question 3566

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old man with medial compartment knee osteoarthritis is being considered for a unicompartmental knee arthroplasty (UKA). Which of the following is considered an absolute contraindication for a medial UKA?

. Age < 60 years
. Body mass index of 35 kg/m2
. Prior partial medial meniscectomy
. Absent anterior cruciate ligament with clinical instability
. Patellofemoral chondromalacia without anterior knee pain

Correct Answer & Explanation

. Absent anterior cruciate ligament with clinical instability

Explanation

An absent anterior cruciate ligament with clinical instability leads to altered kinematics and accelerated failure in a medial UKA. It is widely considered a strict contraindication, whereas age, obesity, and asymptomatic patellofemoral changes are relative.

Question 3567

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old man presents with new-onset groin pain 6 years after a metal-on-polyethylene THA with a modular titanium stem and cobalt-chromium head. Radiographs show no loosening. Serum cobalt is 8.5 ppb and chromium is 1.2 ppb. What is the best next step in management?

. Revision to a ceramic head and new polyethylene liner
. Immediate removal of all components and insertion of an antibiotic spacer
. Metal artifact reduction sequence (MARS) MRI of the hip
. Observation and repeat labs in 1 year
. Ultrasound-guided aspiration for culture

Correct Answer & Explanation

. Metal artifact reduction sequence (MARS) MRI of the hip

Explanation

Elevated serum cobalt levels with normal chromium in a metal-on-polyethylene THA indicates trunnionosis (corrosion at the head-neck taper). A MARS MRI is the best next step to evaluate for an adverse local tissue reaction (ALTR) or pseudotumor.

Question 3568

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old woman is 6 weeks post-primary TKA and has a range of motion of 10 to 75 degrees despite aggressive physical therapy. She has no signs of infection and radiographs show well-fixed, well-aligned components. What is the most appropriate next step?

. Revision total knee arthroplasty
. Manipulation under anesthesia (MUA)
. Arthroscopic lysis of adhesions
. Continue physical therapy for another 6 weeks without intervention
. Open quadriceps snip

Correct Answer & Explanation

. Manipulation under anesthesia (MUA)

Explanation

Manipulation under anesthesia (MUA) is most effective when performed between 6 and 12 weeks postoperatively for arthrofibrosis after TKA. Delaying intervention beyond this window decreases the likelihood of successfully restoring motion.

Question 3569

Topic: Total Hip Arthroplasty (THA)

Following a primary THA via a direct anterior approach, a patient complains of numbness and burning pain over the anterolateral thigh. Which of the following intraoperative maneuvers most likely caused this complication?

. Aggressive retraction of the tensor fasciae latae
. Dissection medial to the sartorius muscle
. Excessive reaming of the acetabulum
. Injury to the superior gluteal nerve during capsule release
. Retraction of the rectus femoris muscle

Correct Answer & Explanation

. Aggressive retraction of the tensor fasciae latae

Explanation

The lateral femoral cutaneous nerve (LFCN) is at risk during the direct anterior approach. Aggressive retraction of the tensor fasciae latae or dissection lateral to the sartorius can compress or stretch the LFCN, causing anterolateral thigh paresthesias.

Question 3570

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old man is 3 weeks status post primary TKA and presents with a 4-day history of increasing knee pain, erythema, and a temperature of 38.5 C. Joint aspiration yields purulent fluid. Which of the following is the most appropriate indication for proceeding with Debridement, Antibiotics, and Implant Retention (DAIR)?

. Presence of a draining sinus tract
. Symptoms lasting longer than 4 weeks
. Well-fixed components with acute symptom onset (< 3 weeks post-op)
. Infection with Methicillin-resistant Staphylococcus aureus
. Loosening of the tibial component on radiographs

Correct Answer & Explanation

. Well-fixed components with acute symptom onset (< 3 weeks post-op)

Explanation

DAIR is indicated for early postoperative infections (typically within 4 weeks of surgery) or acute hematogenous infections with symptom duration of less than 3 weeks, provided the implants are stable and the soft tissue envelope is intact.

Question 3571

Topic: 3. Adult Reconstruction (Hip & Knee)

A 50-year-old woman with a metal-on-metal THA presents with a palpable groin mass and discomfort. A MARS MRI demonstrates a large, thick-walled cystic lesion communicating with the joint space. What histological characteristic is most commonly associated with this condition?

. Intense neutrophilic infiltrate
. Perivascular lymphocytic infiltrate and extensive tissue necrosis
. Fungal hyphae
. Non-caseating granulomas
. Abundant multinucleated giant cells with polyethylene debris

Correct Answer & Explanation

. Perivascular lymphocytic infiltrate and extensive tissue necrosis

Explanation

Adverse local tissue reactions (ALTR) or pseudotumors in metal-on-metal THA are characterized histologically by an aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). This involves perivascular lymphocytic infiltrates and extensive tissue necrosis.

Question 3572

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old woman sustains a fall resulting in a periprosthetic femur fracture around her cemented THA stem. Radiographs show a spiral fracture around the stem tip, and the stem has subsided 1 cm, indicating it is loose. Bone stock is adequate. According to the Vancouver classification, what is the most appropriate management?

. Open reduction internal fixation with cerclage cables and a laterally based plate
. Non-operative management with skeletal traction
. Revision of the femoral stem to a long diaphyseal-engaging stem
. Impaction bone grafting alone
. Excision arthroplasty

Correct Answer & Explanation

. Revision of the femoral stem to a long diaphyseal-engaging stem

Explanation

This is a Vancouver B2 fracture (fracture around the stem, loose stem, adequate bone stock). The standard of care is revision arthroplasty using a long, diaphyseal-engaging stem (fluted tapered or fully porous-coated) to bypass the fracture and achieve stability.

Question 3573

Topic: Total Hip Arthroplasty (THA)

During a posterolateral approach THA, which intraoperative landmark is most reliable for assessing leg length and offset changes prior to final component implantation?

. Distance from the lesser trochanter to the greater trochanter
. Measurement between a pin in the ilium and a fixed mark on the greater trochanter
. The level of the piriformis fossa relative to the acetabulum
. The tension of the intact iliopsoas tendon
. Palpation of the anterior superior iliac spine

Correct Answer & Explanation

. Measurement between a pin in the ilium and a fixed mark on the greater trochanter

Explanation

The most reliable intraoperative method to assess leg length and offset is to measure the distance between a fixed point on the pelvis (like a Steinman pin in the ilium) and a fixed reference point on the proximal femur (like a cautery mark on the greater trochanter).

Question 3574

Topic: Total Knee Arthroplasty (TKA)

A patient complains of anterior knee pain and a "clunking" sensation 6 months following a primary TKA. Examination shows lateral patellar subluxation in early flexion. Which component malposition is most likely responsible for this finding?

. External rotation of the femoral component
. Internal rotation of the femoral or tibial components
. Excessive posterior slope of the tibial tray
. Valgus placement of the tibial tray
. Lateralization of the femoral component

Correct Answer & Explanation

. Internal rotation of the femoral or tibial components

Explanation

Internal rotation of either the femoral or tibial components increases the Q-angle, which pulls the extensor mechanism laterally. This leads to lateral patellar maltracking, subluxation, and anterior knee pain.

Question 3575

Topic: 3. Adult Reconstruction (Hip & Knee)

A 42-year-old woman with severe bilateral hip osteoarthritis desires a hip resurfacing arthroplasty to maintain her high level of athletic activity. Which of the following factors is considered the most significant contraindication for hip resurfacing in this patient?

. Her desired high activity level
. Female sex and typically smaller femoral head size
. Absence of a femoral neck cyst
. Her age of 42 years
. A BMI of 25 kg/m2

Correct Answer & Explanation

. Female sex and typically smaller femoral head size

Explanation

Hip resurfacing is generally contraindicated in female patients and those with smaller femoral head sizes. These patients have a significantly higher risk of femoral neck fracture, implant failure, and adverse local tissue reactions from metal wear.

Question 3576

Topic: 3. Adult Reconstruction (Hip & Knee)

In considering the design of a total knee arthroplasty, which of the following is a recognized indication for using a posterior-stabilized (PS) design rather than a cruciate-retaining (CR) design?

. Intact and functional posterior cruciate ligament
. Mild flexion contracture of 5 degrees
. Prior patellectomy
. Varus deformity of 5 degrees
. Patient age greater than 80 years

Correct Answer & Explanation

. Prior patellectomy

Explanation

A prior patellectomy alters knee kinematics and extensor mechanism mechanics, often leading to anterior-posterior instability. A posterior-stabilized (PS) design is recommended in these cases to substitute for the PCL and provide reliable AP stability.

Question 3577

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty, the surgeon notes that the joint space is symmetrically tight in flexion, but perfectly balanced and symmetric in extension. Which of the following is the most appropriate next step to correct this mismatch?

. Release the posterior capsule
. Resect more distal femur
. Decrease the anteroposterior size of the femoral component
. Increase the thickness of the tibial polyethylene
. Release the superficial medial collateral ligament

Correct Answer & Explanation

. Decrease the anteroposterior size of the femoral component

Explanation

A knee that is balanced in extension but tight in flexion requires an increase in the flexion gap. This is achieved by downsizing the femoral component (reducing the AP diameter) or increasing the posterior slope of the tibial cut.

Question 3578

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 utilizing a titanium stem and a large-diameter cobalt-chromium head. Inflammatory markers are normal. Aspiration yields sterile, cloudy fluid, and MRI demonstrates a thick-walled cystic pseudotumor. What is the most likely etiology?

. Polyethylene wear osteolysis
. Missed periprosthetic joint infection
. Mechanically assisted crevice corrosion at the head-neck taper
. Impingement of the iliopsoas tendon
. Galvanic corrosion at the stem-cement interface

Correct Answer & Explanation

. Mechanically assisted crevice corrosion at the head-neck taper

Explanation

The scenario describes adverse local tissue reaction (ALTR) due to mechanically assisted crevice corrosion, also known as trunnionosis. This is classic for a metal-on-polyethylene THA with a large cobalt-chromium head on a titanium stem presenting with a sterile pseudotumor.

Question 3579

Topic: 3. Adult Reconstruction (Hip & Knee)

An 80-year-old man presents with a periprosthetic femur fracture around a cementless THA stem after a fall. Radiographs reveal a fracture at the tip of the stem, and comparison with previous films shows the stem has subsided 2.5 cm. The surrounding bone stock is adequate. What is the standard of care?

. Open reduction and internal fixation with cerclage wires only
. Open reduction and internal fixation with a lateral locking plate
. Revision to a long cementless diaphyseal-engaging stem
. Proximal femoral replacement
. Cortical strut allografting without hardware

Correct Answer & Explanation

. Revision to a long cementless diaphyseal-engaging stem

Explanation

This describes a Vancouver B2 periprosthetic fracture (fracture around the stem, loose implant, good bone stock). The standard treatment is revision arthroplasty bypassing the fracture site with a long, diaphyseal-fitting stem.

Question 3580

Topic: 3. Adult Reconstruction (Hip & Knee)

A 67-year-old woman presents 14 months after a posterior-stabilized TKA complaining of a painful catching sensation at the anterior aspect of her knee when extending from a flexed position. The catch consistently occurs around 35 degrees of flexion. What is the most likely diagnosis?

. Patellofemoral overstuffing
. Patellar clunk syndrome
. Aseptic loosening of the tibial tray
. Popliteus tendon impingement
. Fabella syndrome

Correct Answer & Explanation

. Patellar clunk syndrome

Explanation

Patellar clunk syndrome occurs in posterior-stabilized knees when a fibro-synovial nodule forms at the superior pole of the patella. This nodule catches in the femoral intercondylar notch during active extension, typically between 30 and 45 degrees.

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