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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 96 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 1901

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the 2018 International Consensus Meeting (ICM) criteria for Periprosthetic Joint Infection (PJI), which of the following is considered a 'major' criterion that, if present, definitively establishes the diagnosis of PJI?

. Elevated serum C-reactive protein (CRP)
. Elevated synovial fluid white blood cell count
. A single positive periprosthetic tissue culture
. A sinus tract communicating with the prosthesis
. Positive synovial fluid alpha-defensin immunoassay

Correct Answer & Explanation

. A sinus tract communicating with the prosthesis

Explanation

The 2018 ICM criteria establish two 'major' criteria for definitive PJI diagnosis: 1) a sinus tract communicating directly with the joint space/prosthesis, or 2) two positive periprosthetic cultures yielding phenotypically identical organisms. The other listed options are considered 'minor' criteria or biomarkers used in the scoring algorithm.

Question 1902

Topic: 3. Adult Reconstruction (Hip & Knee)

A 19-year-old rugby player sustains a posteriorly displaced sternoclavicular (SC) joint dislocation. He is hemodynamically stable but complains of dysphagia and voice changes. A closed reduction in the operating room with a cardiothoracic surgeon on standby is attempted but fails. What is the next most appropriate step in management?

. Observation in a figure-of-eight brace
. Open reduction and internal fixation with smooth Kirschner wires
. Open reduction and stabilization with a figure-of-eight tendon graft
. Resection arthroplasty of the medial clavicle
. CT angiography followed by observation

Correct Answer & Explanation

. Open reduction and stabilization with a figure-of-eight tendon graft

Explanation

Posterior SC dislocations that fail closed reduction or cause ongoing compression of mediastinal structures (trachea, esophagus, great vessels) require open reduction. The gold standard for surgical stabilization is reconstruction using a figure-of-eight tendon graft (e.g., semitendinosus or palmaris). Kirschner wires and pins are strictly contraindicated due to the high risk of fatal hardware migration into the heart or great vessels.

Question 1903

Topic: 3. Adult Reconstruction (Hip & Knee)

In the diagnostic workup for periprosthetic joint infection (PJI), the alpha-defensin immunoassay is frequently utilized as a highly specific synovial fluid biomarker. Alpha-defensin is an antimicrobial peptide primarily secreted by which of the following cell types in response to pathogens?

. Macrophages
. T-lymphocytes
. Neutrophils
. Synoviocytes
. Osteoblasts

Correct Answer & Explanation

. Neutrophils

Explanation

Alpha-defensin is an antimicrobial peptide naturally secreted by host neutrophils in response to the presence of bacterial pathogens. It has high sensitivity and specificity for the diagnosis of PJI and is less affected by prior antibiotic administration than standard synovial fluid cultures.

Question 1904

Topic: 3. Adult Reconstruction (Hip & Knee)

When evaluating a patient for a suspected periprosthetic joint infection (PJI), a synovial fluid leukocyte esterase (LE) test is performed. Which of the following is the most common cause of a false-positive LE test in this setting?

. Prior antibiotic administration within 2 weeks
. Presence of visible blood in the aspirate
. Metallosis from bearing wear
. Concomitant crystalline arthropathy
. Polyethylene debris

Correct Answer & Explanation

. Presence of visible blood in the aspirate

Explanation

The leukocyte esterase strip test relies on a colorimetric change to detect the enzyme produced by neutrophils. Significant amounts of red blood cells (bloody aspirate) can obscure the color change or cause a false-positive reading.

Question 1905

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female sustains a displaced intracapsular femoral neck fracture. Which of the following is TRUE regarding the long term differences between possible treatment options for this injury?

. Patients undergoing total hip arthroplasty are more likely to experience persistent pain than those undergoing internal fixation
. Patients undergoing total hip arthroplasty are less likely to require reoperation than those undergoing internal fixation
. There is no difference in functional outcome scores between internal fixation and total hip arthroplasty
. Patients undergoing internal fixation perform activities of daily living better than those undergoing total hip arthroplasty
. Mortality rates are higher following total hip arthroplasty than internal fixation

Correct Answer & Explanation

. Patients undergoing total hip arthroplasty are less likely to require reoperation than those undergoing internal fixation

Explanation

Elderly patients with femoral neck fractures (FNF) undergoing total hip arthroplasty (THA) are less likely to require reoperation than those undergoing internal fixation.Intracapsular FNF are common in elderly patients after a fall from standing height. Treatment depends on physiological age and displacement (Garden's classification). For displaced fractures, physiologically young patients are treated with internal fixation while physiologically old patients are treated with either hemiarthroplasty (debilitated, less active patients) or THA (more active patients, those with acetabulardisease or preexisting inflammatory arthritis).Chammout et al. retrospectively compared the long term (17 years) results of THA (cemented both component) and ORIF (2 cannulated screws) in elderly patients (>65 years). They found no difference in mortality. But hip scores were higher and pain was better in the THA group, while reoperation rates were higher in the ORIF group. Walking speed was initially faster in the THA group, but later did not differ between groups. They recommend THA for elderly patients with displaced FNF.Rogmark et al. prospectively compared closed reduction and internal fixation (CRIF) with arthroplasty (combining hemiarthroplasty and THA) at 2 years in elderly patients (>70 years). Failure rates were higher, pain was worse, and walking was more impaired after CRIF. They recommend arthroplasty for patients >70 with FNF.

Question 1906

Topic: Total Knee Arthroplasty (TKA)
During primary total knee arthroplasty with trial implants in place, the surgeon notes technically satisfactory patellar resurfacing and restoration of a physiologic mechanical axis but excessively lateral patellar tracking. Treatment should now include:
. a lateral retinacular release.
. a tubercle transfer to reduce the Q angle.
. a repeat of the tibial and femoral cuts to introduce 5° of varus.
. release of the popliteus.
. medial vastus advancement.

Correct Answer & Explanation

. a lateral retinacular release.

Explanation

DISCUSSION: The most common causes of patellar instability after total knee arthroplasty are valgus malalignment, internal rotation of the femoral or tibial component, medialization of the femoral component, errors in patellar preparation and resurfacing, and failure to perform a lateral release. These factors should be addressed before considering capsular closure.

Question 1907

Topic: 3. Adult Reconstruction (Hip & Knee)

During a posterior-stabilized total knee arthroplasty, the surgeon finds the knee to be well-balanced in full extension but excessively tight in 90 degrees of flexion. Which of the following is the most appropriate next step to correct this mismatch?

. Recut the distal femur to remove more bone
. Release the posterior capsule
. Upsize the femoral component
. Decrease the posterior slope of the tibial cut
. Downsize the femoral component

Correct Answer & Explanation

. Downsize the femoral component

Explanation

A knee that is tight in flexion but balanced in extension requires an adjustment to the flexion gap only. Downsizing the femoral component (using an anterior referencing system) or increasing the posterior tibial slope will increase the flexion gap.

Question 1908

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old female presents with an audible and palpable 'clunk' at the anterior knee when extending her leg from 40 degrees of flexion to full extension, one year after a total knee arthroplasty. What implant design characteristic is most frequently associated with this complication?

. Cruciate-retaining femur with a shallow trochlear groove
. Posterior-stabilized femur with a high intercondylar box ratio
. Mobile-bearing polyethylene with a highly conforming coronal geometry
. Use of an asymmetric patellar button
. Medial pivot design with a prominent anterior tibial lip

Correct Answer & Explanation

. Posterior-stabilized femur with a high intercondylar box ratio

Explanation

Patellar clunk syndrome is most commonly associated with posterior-stabilized (PS) implants that have a high or sharp anterior intercondylar box. Fibrous tissue forms at the superior pole of the patella and catches in the box during extension.

Question 1909

Topic: 3. Adult Reconstruction (Hip & Knee)

A 72-year-old female with a history of a cementless total hip arthroplasty presents with thigh pain after a ground-level fall. Radiographs demonstrate a fracture around the tip of the femoral stem. The stem is visibly loose and has subsided 5 mm compared to previous films, but the proximal femur maintains excellent circumferential bone stock. According to the Vancouver classification, what is the fracture type and the recommended standard of care?

. Vancouver A: ORIF with cerclage cables
. Vancouver B1: ORIF with a locking plate and cerclage cables
. Vancouver B2: Revision arthroplasty with a long, extensively porous-coated stem
. Vancouver B3: Revision arthroplasty with proximal femoral replacement
. Vancouver C: ORIF with a spanning locking plate

Correct Answer & Explanation

. Vancouver B2: Revision arthroplasty with a long, extensively porous-coated stem

Explanation

The Vancouver classification guides treatment for periprosthetic femur fractures. A fracture around the stem (Type B) with a loose stem but good proximal bone stock is a Vancouver B2 fracture. The standard of care is revision arthroplasty using a long stem (often extensively porous-coated or fluted tapered) to bypass the fracture and achieve stable fixation in the intact distal bone.

Question 1910

Topic: 3. Adult Reconstruction (Hip & Knee)
A 45-year-old woman has severe anterior knee pain. Her radiographs indicate end-stage patellofemoral compartment osteoarthritis. The tibiofemoral compartments are preserved. Extensive nonsurgical treatment has failed to provide relief, and she is offered patellofemoral arthroplasty (PFA). What is the most common long-term mode of failure for PFA using an implant with an onlay prosthesis design?
. Infection
. Patellar instability
. Aseptic loosening
. Progression of tibiofemoral arthritis

Correct Answer & Explanation

. Progression of tibiofemoral arthritis

Explanation

Discussion: Contemporary onlay-design trochlear prostheses in PFA replace the entire anterior trochlear surface. Previous inlay designs were inset within the native trochlea and carried a higher risk of catching and patellar instability, particularly in patients with trochlear dysplasia; they also generally have higher failure rates. The current most common mode of failure is progression of arthritis throughout the knee, in some series as high as 25% at 15 years. Aseptic loosening, particularly of cemented implants, is less common. Infection is an uncommon long-term complication. Patients considering PFA should be advised of the risk of arthritis progression. Many authors routinely obtain a preoperative MRI to assess the status of the tibiofemoral compartments.

Question 1911

Topic: Total Knee Arthroplasty (TKA)
A woman has a history of gradually increasing diffuse and global right knee pain. Her main issues are difficulty with stairs, stiffness with prolonged sitting, and swelling. She has taken NSAIDs and has received intra-articular steroid injections, all with decreasing efficacy. Her right knee examination reveals a range of motion of 15° to 80° with a fixed deformity to varus and valgus stress. Her symptoms are no longer manageable nonsurgically. Radiographs reveal a mechanical axis deformity. When using the measured resection technique during total knee arthroplasty (TKA), the best way to avoid femoral malrotation is to reference the
. anteroposterior axis.
. tibial intramedullary axis.
. posterior condylar axis.
. femoral intramedullary axis.

Correct Answer & Explanation

. posterior condylar axis.

Explanation

Discussion: In the setting of valgus deformities, TKA poses different challenges than those encountered when varus deformities are present. Most valgus alignment is attributable to a deformity of the distal femur rather than of the proximal tibia, as seen in varus knees. One of the major anatomical differences is a hypoplastic lateral femoral condyle which, when not recognized and used as a rotational reference point, can lead to internal rotation of the femoral component. This malrotation in turn leads to patellofemoral maltracking or instability, which is a common complication associated with primary TKA.

Question 1912

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old man presents with severe, end-stage ankle osteoarthritis. Radiographs reveal bone-on-bone tibiotalar arthritis, 25 degrees of coronal plane varus deformity, and avascular necrosis involving 60% of the talar body. What is the most appropriate definitive surgical intervention?

. Standard total ankle arthroplasty
. Custom total ankle arthroplasty with talar component
. Tibiotalocalcaneal (TTC) arthrodesis with a retrograde intramedullary nail
. Supramalleolar osteotomy
. Arthroscopic ankle arthrodesis

Correct Answer & Explanation

. Tibiotalocalcaneal (TTC) arthrodesis with a retrograde intramedullary nail

Explanation

Significant avascular necrosis of the talus (>50%) and severe coronal plane deformity are absolute contraindications for standard total ankle arthroplasty. A tibiotalocalcaneal (TTC) arthrodesis is the most reliable treatment to address both the arthritis and the compromised talar bone stock.

Question 1913

Topic: 3. Adult Reconstruction (Hip & Knee)
A 3-year-old boy is referred to you because of "abnormal radiographs". The child's radiographs are shown in Figures A and B. This patient is at increased risk for all of following conditions EXCEPT:
. Appendicular fractures
. Osteomyelitis
. Cranial nerve palsies
. Coxa vara
. Vertebral compression fractures

Correct Answer & Explanation

. Vertebral compression fractures

Explanation

The clinical presentation is consistent with osteopetrosis. Osteopetrosis is associated with appendicular fractures, osteomyelitis, cranial nerve palsies, and coxa vara. Osteopetrosis is not associated with vertebral compression fractures.

Question 1914

Topic: 3. Adult Reconstruction (Hip & Knee)
An otherwise healthy 76-year-old woman has pain 2 years after total hip arthroplasty. The clinical photograph in Figures below demonstrates her skin envelope, and associated radiograph. Her C-reactive protein level is normal, and her erythrocyte sedimentation rate is mildly elevated. The white blood cell count is normal. Hip aspiration attempted under fluoroscopy generates no fluid. What is the best definitive treatment?
. Repeat left hip aspiration
. Initiation of a wound care consult and oral antibiotics
. Irrigation and debridement with closure of the dehisced wound, performance of a liner exchange, and administration of intravenous antibiotics
. Debridement of the wound, explant of the total hip, placement of a spacer, and administration of intravenous antibiotics

Correct Answer & Explanation

. Debridement of the wound, explant of the total hip, placement of a spacer, and administration of intravenous antibiotics

Explanation

This patient clearly has a chronically infected total hip arthroplasty, indicated by the open, draining sinus, as well as trochanteric bone resorption on radiographs, and two years of pain. In this particular case, the patient is chronically infected, requiring a two-stage exchange.

Question 1915

Topic: 3. Adult Reconstruction (Hip & Knee)
A 70-year-old male undergoes evaluation for a periprosthetic total hip fracture. Radiographs demonstrate a displaced fracture around the distal tip of the femoral stem. The stem is radiographically loose, and there is severe proximal femoral bone loss and thinning of the cortices (<2 cm of intact diaphyseal bone). According to the Vancouver classification, what is the fracture type and the most appropriate standard surgical treatment?
. Vancouver B1; treatment is ORIF with a locking plate and cables.
. Vancouver B2; treatment is revision to a fully porous-coated long stem.
. Vancouver B3; treatment is revision with a modular fluted tapered stem and structural allograft or a proximal femoral replacement.
. Vancouver C; treatment is ORIF with a laterally based locking plate.
. Vancouver A; treatment is non-operative management with touch-down weight bearing.

Correct Answer & Explanation

. Vancouver B3; treatment is revision with a modular fluted tapered stem and structural allograft or a proximal femoral replacement.

Explanation

This scenario describes a Vancouver B3 periprosthetic fracture: the fracture occurs around the stem (B), the stem is loose (3), and there is poor bone stock (severe proximal bone loss). The standard of care for a Vancouver B3 fracture is revision arthroplasty using a modular, fluted, tapered stem bypassing the fracture, often supplemented with structural allografts, or utilizing a proximal femoral replacement (megaprosthesis) in older, lower-demand patients. B2 fractures involve a loose stem with GOOD bone stock and are treated with long stem revision.

Question 1916

Topic: 3. Adult Reconstruction (Hip & Knee)

A 35-year-old male is involved in a high-speed motor vehicle collision. Radiographs and CT demonstrate a posterior hip dislocation with an associated posterior wall acetabular fracture. There is a distinct area of marginal impaction of the articular cartilage. What is the most appropriate management of the marginal impaction during open reduction and internal fixation?

. Excision of the impacted articular segment and replacement with a structural allograft
. Leaving the impacted segment in situ to prevent avascular necrosis of the fragment
. Elevation of the impacted segment, filling the metaphyseal void with bone graft, and buttressing it with the posterior wall
. Securing the impacted segment with headless compression screws directly through the articular surface without grafting
. Performing an immediate total hip arthroplasty due to predictably poor outcomes

Correct Answer & Explanation

. Elevation of the impacted segment, filling the metaphyseal void with bone graft, and buttressing it with the posterior wall

Explanation

Marginal impaction is common in posterior wall acetabular fractures. Failure to recognize and elevate this impacted articular cartilage leads to joint incongruity and rapid post-traumatic arthritis. The standard of care is to disimpact and elevate the articular segment to match the femoral head, fill the resulting subchondral/metaphyseal void with cancellous bone graft, and then reduce and fix the posterior wall over it to act as a buttress.

Question 1917

Topic: 3. Adult Reconstruction (Hip & Knee)
A 70-year-old woman experiences pain 1 year after total knee arthroplasty (TKA). She reports sharp anterior pain and a painful catching sensation that is aggravated by rising from a chair or climbing stairs. Physical examination reveals a mild effusion and a range of motion of 2° to 130°, with patellar crepitus. The symptoms are reproduced by resisted knee extension. Radiographs show a well-aligned posterior-stabilized TKA without evidence of component loosening. What is the recommended treatment for this patient?
. Physical therapy
. Arthroscopic synovectomy
. Tibial insert revision
. Femoral component revision

Correct Answer & Explanation

. Arthroscopic synovectomy

Explanation

DISCUSSION: Patellar clunk syndrome is caused by the development of a fibrous nodule on the posterior aspect of the quadriceps tendon at its insertion into the patella. It causes a painful catching sensation when the extensor mechanism traverses over the trochlear notch as the knee extends from 45° of flexion to 30° from full extension. It characteristically occurs in posterior-stabilized total knee arthroplasties and appears to be related to femoral component design. The syndrome can usually be prevented by excising the residual synovial fold just proximal to the patella. Patellar clunk syndrome can usually be addressed successfully with arthroscopic synovectomy.

Question 1918

Topic: 3. Adult Reconstruction (Hip & Knee)
Figure 23 shows the radiograph of a 55-year-old man who underwent a total hip arthroplasty 5 years ago. Management should now consist of:
. an Ogden-type plate with screws and cerclage bands or cables.
. allograft bone plates fixed with cerclage cables and wires.
. skeletal traction for 8 weeks.
. revision of the femoral stem.
. resection arthroplasty.

Correct Answer & Explanation

. revision of the femoral stem.

Explanation

DISCUSSION: Because the radiograph shows that the femoral stem is loose within the femoral canal and there is a fracture in the distal cement mantle, the stem should be revised. The Ogden-type plate and the allograft bone plates will reconstruct the femur but will not restore stability to the stem. Similarly, traction may allow the femur to heal but will not restore stability to the femoral stem within the femur. Resection arthroplasty is considered a salvage option following failure of the other procedures.

Question 1919

Topic: Total Hip Arthroplasty (THA)

Which factor is most highly associated with the clinical phenomenon of 'squeaking' in a ceramic-on-ceramic total hip arthroplasty?

. Component malposition leading to edge loading
. Use of a short femoral neck
. Use of an extended high-offset stem
. Patient body mass index (BMI) less than 25
. Use of a 28-mm femoral head

Correct Answer & Explanation

. Component malposition leading to edge loading

Explanation

Squeaking in ceramic-on-ceramic THA is highly associated with edge loading, which typically results from component malposition (such as excessive acetabular cup inclination or anteversion outliers). Edge loading causes a loss of fluid film lubrication and stripe wear, ultimately leading to audible squeaking.

Question 1920

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old female complains of instability particularly when descending stairs 1 year following a primary total knee arthroplasty. On examination, her knee is completely stable in full extension, but demonstrates 15 degrees of varus/valgus laxity at 90 degrees of flexion. Which intraoperative technical error most likely caused this specific pattern of instability?

. Over-resection of the distal femur
. Under-resection of the distal femur
. Over-resection of the posterior femoral condyles
. Use of an oversized femoral component
. Failure to release the medial collateral ligament

Correct Answer & Explanation

. Over-resection of the posterior femoral condyles

Explanation

The patient presents with flexion instability (a loose flexion gap with a stable extension gap). This is classically caused by over-resection of the posterior femoral condyles, undersizing the femoral component in the anteroposterior plane, or excessive posterior slope of the tibial cut.

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