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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 70 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 1381

Topic: 3. Adult Reconstruction (Hip & Knee)
A man is about to undergo right total hip arthroplasty. A preoperative AP pelvis radiograph is shown. The final acetabular component and polyethylene liner are implanted. With the broach in place, the surgeon trials a standard offset neck and neutral length femoral head. The leg lengths are approximately equal, but the hip is unstable. What is the best next step?
. Choosing a longer femoral head and accepting a resulting leg-length discrepancy
. Trialing a lateralized femoral neck component
. Removing the acetabular liner and implanting an offset liner instead
. Performing a trochanteric osteotomy with advancement

Correct Answer & Explanation

. Trialing a lateralized femoral neck component

Explanation

The radiograph shows that this patient has a high offset varus femoral morphology of both hips. Preoperative templating would identify this, and the surgeon should choose an implant system that has extended offset options to help match the native anatomy and biomechanics and minimize the risk of instability. Trialing a high offset neck, rather than a standard offset neck, is the next most appropriate step. Depending on the design of the implant system, this step can be accomplished by direct medialization of the femoral head, which would not affect leg length, or by lowering the neck angle, which would affect the leg length and would require a longer femoral head, because the leg lengths had previously been equal.

Question 1382

Topic: 3. Adult Reconstruction (Hip & Knee)
Hip pain of 1-month duration has developed in a 72-year-old man with a previous total hip arthroplasty. He underwent dental work 6 weeks ago. Aspiration shows a white blood cell count of more than 6,000 cells/μL (reference range 4,500 to 11,000 cells/μL) and the presence of gram-positive cocci in clusters on Gram stain. The orthopaedic surgeon recommends urgent debridement and irrigation. Fixation of the components is judged to be stable, and the surgeon elects to retain the implants. What is this patient's prognosis for infection resolution?
. Good because it is a gram-positive organism
. Good because it is an acute infection
. Poor because it is a gram-positive organism
. Poor because it is a late infection

Correct Answer & Explanation

. Poor because it is a late infection

Explanation

The patient has a late infection of at least 4 weeks symptomatic duration that most likely is hematogenous in etiology. This infection is not an acute hematogenous infection that can successfully be treated with irrigation and debridement. Retention of the implants with debridement and irrigation alone has been associated with a poor prognosis.

Question 1383

Topic: 3. Adult Reconstruction (Hip & Knee)
A direct lateral (Hardinge) approach is used during total hip arthroplasty. The structure labeled A in Figure 7 is the
. superior gluteal nerve.
. inferior gluteal nerve.
. obturator nerve.
. medial femoral circumflex artery.
. lateral femoral circumflex artery.

Correct Answer & Explanation

. superior gluteal nerve.

Explanation

Discussion: The superior gluteal nerve is located approximately 7.82 cm above the tip of the greater trochanter as it courses through the gluteus medius. This anatomic consideration is relevant during a Hardinge approach to the hip, where excessive proximal dissection or retraction could result in nerve injury.

Question 1384

Topic: 3. Adult Reconstruction (Hip & Knee)
An 82-year-old woman reports activity-related knee pain. History reveals that she underwent total knee arthroplasty 16 years ago. AP and lateral radiographs and a bone scan are shown in Figures 38a through 38c. What is the most likely diagnosis?
. Particle-mediated osteolysis
. Metastatic carcinoma
. Stress shielding
. Septic joint
. Osteosarcoma

Correct Answer & Explanation

. Particle-mediated osteolysis

Explanation

The radiographs reveal a large femoral metaphyseal lytic lesion with well-defined borders. Joint space narrowing medially is consistent with polyethylene wear. The most likely diagnosis is particle-mediated osteolysis.

Question 1385

Topic: 3. Adult Reconstruction (Hip & Knee)
A 40-year-old man with a history of Legg-Calve-Perthes disease underwent a right hip resurfacing 3 years ago with no perioperative complications. Hip pain has developed gradually during the last 4 months. Radiographs show no evidence of fixation loosening or any adverse changes at the femoral neck. No periarticular osteolysis is evident. A large intra-articular and intrapelvic pseudotumor has developed. What predominant histological feature(s) is/are present in such a lesion?
. Polymorphonuclear leukocytes
. Extracellular metal-wear debris
. Cement particles within the macrophages
. Lymphocytes and plasma cells

Correct Answer & Explanation

. Lymphocytes and plasma cells

Explanation

Adverse tissue reaction has been identified to occur around metal-on-metal (MOM) hip arthroplasties. The predominant histologic feature is tissue necrosis with infiltration of lymphocytes and plasma cells.

Question 1386

Topic: 3. Adult Reconstruction (Hip & Knee)
Figures 189a through 189d are the radiograph and MR images of the right hip of a 28-year-old woman who has had right hip pain for 3 years. The pain is felt in the groin area, is exacerbated by weight-bearing activities, and interferes with her activities of daily living. She has been seen several times and has attempted anti-inflammatory medications, physical therapy, and an intra-articular steroid injection with minimal relief. What is the most appropriate next step?
. Hip arthroscopy and debridement
. Periacetabular osteotomy
. Femoral varus-producing osteotomy
. Total hip arthroplasty (THA)

Correct Answer & Explanation

. Periacetabular osteotomy

Explanation

This patient has dysplasia with a lack of lateral femoral head coverage. A Ganz periacetabular osteotomy can provide more adequate coverage of the femoral head and is a multiplanar correction of the dysplastic acetabulum. This osteotomy is an effective treatment for symptomatic dysplasia in prearthritic young adult hips.

Question 1387

Topic: 3. Adult Reconstruction (Hip & Knee)
A 75-year-old patient returns for follow-up after undergoing bilateral total hip arthroplasty (THA). The right hip is a hybrid THA performed 12 years ago, whereas the left hip is a cementless THA performed 10 years ago. Both acetabular components are the same type, same size, and from the same manufacturer. Both femoral heads are 28-mm cobalt-chromium components. What is the most likely explanation for the advanced polyethylene wear in one hip?
. Presence of a third-party abrasive particle
. Disproportionate use of the limbs by the patient
. Defective femoral head
. Method of fixation of the femoral component
. Method of sterilization and shelf life of the polyethylene

Correct Answer & Explanation

. Method of sterilization and shelf life of the polyethylene

Explanation

Severity of oxidation and a decrease in mechanical properties have been shown to be related to the length of time that the component is exposed to air (the shelf life). Both in vivo and in vitro data suggest that shelf life in excess of 3 to 5 years has a direct effect on wear of polyethylene.

Question 1388

Topic: 3. Adult Reconstruction (Hip & Knee)
The insurance carrier of a patient who underwent total knee arthroplasty 4 days ago is now demanding that the patient be discharged from the hospital. However, examination reveals that the patient has a range of motion of only 10° to 55°, and the patient is concerned whether she will ever move her knee normally. The insurance company representative should be advised that
. discharge at this time may result in loss of motion and the necessity of manipulation under anesthesia.
. the insurance company has no right to make such demands on the surgeon or the patient.
. if the patient is discharged and fails to regain full motion, she will most likely file a suit against the insurance company.
. the patient will require a follow-up examination in 6 weeks to evaluate her progress.
. the patient will be given an extra set of exercises to perform at home.

Correct Answer & Explanation

. discharge at this time may result in loss of motion and the necessity of manipulation under anesthesia.

Explanation

DISCUSSION: Examination findings that show flexion of only 55° at discharge should alert the surgeon that the patient will require close scrutiny and follow-up. Patients requiring manipulation consistently had a lower range of motion at the time of discharge compared with patients not requiring manipulation.

Question 1389

Topic: 3. Adult Reconstruction (Hip & Knee)
A 62-year-old man who underwent total knee arthroplasty 6 months ago now reports pain after falling on the anterior portion of the knee. Examination reveals weakness of knee extension but no extensor lag. Flexion that had once measured 115 degrees is now limited to 70 degrees because of pain. A radiograph is shown. Management should now consist of
. immediate repair of the ruptured patellar tendon insertion.
. knee joint aspiration and injection of a local anesthetic to facilitate examination.
. joint aspiration for culture, broad-spectrum antibiotics, and immobilization.
. immobilization until comfortable, followed by protected range of motion and strengthening.
. immediate fracture repair.

Correct Answer & Explanation

. immobilization until comfortable, followed by protected range of motion and strengthening.

Explanation

DISCUSSION: The patient has a type IIIB patellar fracture (inferior pole fracture with an intact patellar tendon). Nonsurgical management is the treatment of choice if there is little displacement and the extensor mechanism is intact.

Question 1390

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female presents with thigh pain after a fall. She had a primary total hip arthroplasty 10 years ago. Radiographs demonstrate a periprosthetic fracture around the femoral stem. The stem is determined to be loose, but there is adequate proximal and distal bone stock.

What is the most appropriate management according to the Vancouver classification system?

. Open reduction and internal fixation with cerclage cables
. Open reduction and internal fixation with a lateral locking plate
. Revision of the femoral component to a long uncemented diaphyseal-engaging stem
. Revision of the femoral component with proximal femoral replacement
. Nonoperative management with a long leg cast

Correct Answer & Explanation

. Open reduction and internal fixation with cerclage cables

Explanation

This is a Vancouver B2 fracture, which involves a loose stem with adequate bone stock. The standard and most appropriate treatment for Vancouver B2 fractures is revision of the femoral component to a longer uncemented stem that bypasses the fracture by at least two cortical diameters to achieve distal fixation, along with stabilization of the fracture.

Question 1391

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary posterior-stabilized total knee arthroplasty, the trial components are placed and the knee's range of motion is assessed. The knee is noted to be excessively tight in both full extension and at 90 degrees of flexion. What is the most appropriate next intraoperative step to achieve proper balancing?

. Resect additional distal femur
. Resect additional posterior femur
. Downsize the femoral component
. Resect additional proximal tibia or use a thinner polyethylene insert
. Perform a complete posterior capsular release

Correct Answer & Explanation

. Resect additional distal femur

Explanation

When a total knee arthroplasty is tight in both flexion and extension, it indicates that both the extension gap and the flexion gap are too small. The tibia affects both gaps equally. Therefore, the most appropriate step is to either use a thinner polyethylene insert or resect more proximal tibia.

Question 1392

Topic: 3. Adult Reconstruction (Hip & Knee)

In the evaluation of a persistently painful total knee arthroplasty, synovial fluid is aspirated and an alpha-defensin test is ordered.

What is the primary role and characteristic of alpha-defensin in this clinical context?

. It is a highly sensitive and specific antimicrobial peptide biomarker for diagnosing periprosthetic joint infection.
. It is an acute-phase reactant primarily used to identify metallosis caused by trunnionosis.
. It is a marker used to quantify the extent of ultra-high-molecular-weight polyethylene wear.
. It is highly specific for ruling out underlying crystalline arthropathies like gout.
. It is the primary serum marker used to confirm aseptic loosening of the tibial baseplate.

Correct Answer & Explanation

. It is a highly sensitive and specific antimicrobial peptide biomarker for diagnosing periprosthetic joint infection.

Explanation

Alpha-defensin is an antimicrobial peptide released by neutrophils in response to pathogens. It is a highly sensitive and specific biomarker for diagnosing periprosthetic joint infection (PJI) from synovial fluid, and notably, its accuracy is not significantly altered by prior systemic antibiotic administration.

Question 1393

Topic: 3. Adult Reconstruction (Hip & Knee)
According to the 2018 International Consensus Meeting (ICM) criteria for periprosthetic joint infection (PJI), which of the following findings is considered a major criterion that independently confirms the diagnosis of a PJI?
. Elevated serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR)
. Grossly purulent fluid observed in the joint space during arthrocentesis
. Two positive periprosthetic tissue or fluid cultures growing the same organism
. Elevated synovial white blood cell count greater than 3,000 cells/μL
. A positive reading on a synovial fluid leukocyte esterase strip

Correct Answer & Explanation

. Two positive periprosthetic tissue or fluid cultures growing the same organism

Explanation

The major criteria for diagnosing PJI (either of which confirms the diagnosis independently) include: 1) A sinus tract communicating with the prosthesis, or 2) The isolation of the same pathogen by culture from at least two separate tissue or fluid samples obtained from the affected joint.

Question 1394

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old female presents with a painful catching sensation and an audible 'clunk' in her knee when extending from a flexed position. She underwent a primary posterior-stabilized total knee arthroplasty 18 months ago.

What is the most likely etiology of her symptoms?

. Avascular necrosis of the remaining patellar bone stock
. Entrapment of a fibrosynovial nodule in the intercondylar notch of the femoral component
. Aseptic loosening of the tibial baseplate causing dynamic impingement
. Undersizing of the femoral component leading to mid-flexion instability
. Overstuffing of the patellofemoral joint with a thick patellar button

Correct Answer & Explanation

. Avascular necrosis of the remaining patellar bone stock

Explanation

Patellar clunk syndrome is a known complication of posterior-stabilized (PS) total knee arthroplasties. It occurs when a fibrosynovial nodule develops at the superior pole of the patella and catches in the intercondylar box of the femoral component during knee extension from a flexed position.

Question 1395

Topic: 3. Adult Reconstruction (Hip & Knee)

Medial unicompartmental knee arthroplasty (UKA) offers a less invasive alternative to total knee arthroplasty for isolated medial compartment osteoarthritis. Which of the following is classically considered an absolute contraindication to performing a medial UKA?

. Patient age greater than 80 years
. Body Mass Index (BMI) greater than 35 kg/m^2
. Mild patellofemoral osteoarthritis without corresponding anterior knee pain
. Inflammatory arthropathy (e.g., Rheumatoid Arthritis)
. A history of prior arthroscopic partial medial meniscectomy

Correct Answer & Explanation

. Patient age greater than 80 years

Explanation

Inflammatory arthropathy, such as rheumatoid arthritis, is an absolute contraindication to unicompartmental knee arthroplasty because the systemic disease process will inevitably affect the remaining native compartments of the joint. Age, obesity, and asymptomatic patellofemoral changes are considered relative contraindications or acceptable depending on the specific patient.

Question 1396

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male with a metal-on-metal total hip arthroplasty placed 8 years ago presents with worsening groin pain and a palpable anterior mass. Serum cobalt and chromium levels are significantly elevated. MRI reveals a solid and cystic mass communicating with the joint space. What is the most likely diagnosis?

. Iliopsoas tendinopathy and bursitis
. Chronic low-virulence periprosthetic joint infection
. Adverse local tissue reaction (ALTR) / pseudotumor
. Massive heterotopic ossification
. Primary soft tissue sarcoma

Correct Answer & Explanation

. Iliopsoas tendinopathy and bursitis

Explanation

Adverse local tissue reaction (ALTR), also known as ALVAL or pseudotumor, is a recognized complication of metal-on-metal hip arthroplasties or trunnionosis. It is characterized by elevated metal ions, a heavy lymphocytic infiltrate, and the formation of solid or cystic masses that can cause pain and tissue destruction.

Question 1397

Topic: 3. Adult Reconstruction (Hip & Knee)

During a primary total knee arthroplasty for a severe varus deformity, the surgeon proceeds with sequential medial releases. After initial osteophyte removal and deep medial collateral ligament (MCL) release, trial components are placed. The knee is noted to be well-balanced in flexion but remains significantly tight on the medial side in full extension.

Which specific structure should be released next to achieve balance?

. Lateral collateral ligament
. Popliteus tendon
. Posteromedial capsule and semimembranosus
. Superficial medial collateral ligament
. Pes anserinus tendons

Correct Answer & Explanation

. Lateral collateral ligament

Explanation

In a varus knee, sequential releases are performed to achieve balance. If the knee remains tight medially in extension but is balanced in flexion, the posteromedial corner (posteromedial capsule and semimembranosus) is tight and should be released. If the knee is tight in both flexion and extension, the superficial MCL is the primary target.

Question 1398

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old male who underwent a ceramic-on-ceramic total hip arthroplasty 3 years ago reports a new, loud 'squeaking' noise emanating from his hip during ambulation. He denies pain or instability. What biomechanical or surgical factor is most strongly associated with the development of squeaking in a ceramic-on-ceramic bearing surface?

. Component malpositioning leading to edge loading
. Patient Body Mass Index (BMI) greater than 40
. Microfracture of the ceramic femoral head
. Subclinical periprosthetic joint infection
. Micromotion from aseptic loosening of the femoral stem

Correct Answer & Explanation

. Component malpositioning leading to edge loading

Explanation

Squeaking in ceramic-on-ceramic total hip arthroplasty is a specific phenomenon most commonly associated with suboptimal component positioning (e.g., excessive or insufficient acetabular cup anteversion or inclination). This malposition leads to edge loading, disruption of fluid-film lubrication, and resultant squeaking.

Question 1399

Topic: 3. Adult Reconstruction (Hip & Knee)

In total hip arthroplasty, the 'safe zone' for acetabular component placement described by Lewinnek is historically targeted to minimize the risk of postoperative dislocation.

What are the classically described target ranges for acetabular abduction (inclination) and anteversion in this zone?

. 40° ± 10° abduction, 15° ± 10° anteversion
. 30° ± 10° abduction, 10° ± 10° anteversion
. 50° ± 10° abduction, 20° ± 10° anteversion
. 45° ± 10° abduction, 5° ± 10° anteversion
. 35° ± 10° abduction, 25° ± 10° anteversion

Correct Answer & Explanation

. 40° ± 10° abduction, 15° ± 10° anteversion

Explanation

The Lewinnek safe zone for acetabular cup placement is classically defined as 40° ± 10° of abduction (inclination) and 15° ± 10° of anteversion. While modern literature recognizes that dislocations can still occur within this zone, it remains the standard foundational target in THA.

Question 1400

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old female sustains a closed Su Type II distal femur fracture superior to a well-fixed posterior-stabilized total knee arthroplasty (TKA). The femoral component has a closed-box design. Assuming closed reduction is possible, what is the most appropriate surgical management?

. Nonoperative management in a hinged long leg cast
. Open reduction and internal fixation with a lateral locking plate
. Retrograde intramedullary nailing
. Revision arthroplasty to a distal femoral replacement
. Application of a bridging external fixator

Correct Answer & Explanation

. Nonoperative management in a hinged long leg cast

Explanation

Fractures above a well-fixed TKA require stable fixation to allow early mobilization. While retrograde nailing is an excellent option for many distal femur fractures, it is generally contraindicated or impossible through a posterior-stabilized TKA with a closed-box design because the intercondylar notch is physically obstructed. Therefore, open reduction and internal fixation with a lateral locking plate is the treatment of choice.

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