Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 230 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 4581

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following approaches to total hip arthroplasty is associated with the highest rate of posterior dislocation during the early postoperative period?

. Direct anterior approach.
. Direct lateral approach.
. Anterolateral approach.
. Posterior approach.
. Minimally invasive approach (irrespective of muscle interval).

Correct Answer & Explanation

. Posterior approach.

Explanation

The posterior approach to total hip arthroplasty, while providing excellent exposure, is traditionally associated with the highest rate of posterior dislocation in the early postoperative period. This is because it typically involves a capsulotomy and detachment of the short external rotators (piriformis, gemelli, obturator internus), which contribute significantly to posterior hip stability. While modern techniques emphasize capsular repair and meticulous soft tissue handling to mitigate this risk, it remains a characteristic complication of this approach compared to others that preserve the posterior capsule and external rotators (e.g., direct anterior, direct lateral). Minimally invasive approaches refer to incision size, not necessarily the specific muscle interval, and thus don't universally predispose to dislocation in one direction.

Question 4582

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following is the most common cause of painful hardware after ankle fracture fixation?

. Infection.
. Aseptic loosening of screws.
. Non-union of the fracture.
. Prominent hardware causing soft tissue irritation.
. Complex regional pain syndrome (CRPS).

Correct Answer & Explanation

. Prominent hardware causing soft tissue irritation.

Explanation

The most common cause of painful hardware after ankle fracture fixation is prominent hardware causing soft tissue irritation. The ankle joint has relatively thin soft tissue coverage, making plates, screws, and wires easily palpable and susceptible to irritation from shoes, socks, or movement. While infection, aseptic loosening, non-union, and CRPS can all cause pain, prominent hardware is by far the most frequent reason for symptomatic hardware removal following ankle fracture surgery. Aseptic loosening is less common with ankle hardware compared to arthroplasty components.

Question 4583

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male undergoes a revision total knee arthroplasty for aseptic loosening of both components. During surgery, significant bone loss is noted in both the distal femur and proximal tibia. What type of implant or technique is most appropriate to address this bone loss and provide stable fixation?

. Standard primary knee components with cement augmentation.
. Unicompartmental knee arthroplasty.
. Hinged knee prosthesis with intramedullary stems and augments.
. Patellofemoral arthroplasty.
. Osteochondral allograft transplantation.

Correct Answer & Explanation

. Hinged knee prosthesis with intramedullary stems and augments.

Explanation

For revision total knee arthroplasty with significant bone loss in both the distal femur and proximal tibia, a hinged knee prosthesis with intramedullary stems and augments is often the most appropriate choice. Intramedullary stems provide enhanced stability in compromised bone. Augments (metal wedges or blocks) are used to fill bone defects and restore joint line. A hinged prosthesis provides greater intrinsic stability, which is crucial when soft tissue constraints are deficient or bone loss is severe. Standard primary components are insufficient for significant bone loss. Unicompartmental and patellofemoral arthroplasties are for isolated compartment disease. Osteochondral allografts are for cartilage defects, not widespread bone loss in revision arthroplasty.

Question 4584

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following describes the most accurate interpretation of a positive Trendelenburg sign?

. Weakness of the hip adductor muscles, causing the pelvis to drop on the affected side.
. Weakness of the hip abductor muscles, causing the pelvis to drop on the unsupported (contralateral) side during single-leg stance.
. Tightness of the iliotibial band, leading to a compensatory gait pattern.
. Pain in the hip joint, causing an antalgic gait.
. Leg length discrepancy, resulting in pelvic tilt.

Correct Answer & Explanation

. Weakness of the hip abductor muscles, causing the pelvis to drop on the unsupported (contralateral) side during single-leg stance.

Explanation

A positive Trendelenburg sign indicates weakness of the hip abductor muscles (primarily gluteus medius and minimus) on the stance leg side. When the patient stands on the affected leg, the pelvis drops on the unsupported (contralateral) side because the weak abductors cannot adequately stabilize the pelvis. This classic sign can be seen in conditions like superior gluteal nerve palsy, avascular necrosis of the femoral head, hip dysplasia, or severe osteoarthritis leading to abductor dysfunction. It is not directly related to adductor weakness, IT band tightness, or pain (though pain can cause an antalgic gait, the Trendelenburg sign is specifically about pelvic drop due to abductor weakness).

Question 4585

Topic: 3. Adult Reconstruction (Hip & Knee)

What is the most significant disadvantage of a unicompartmental knee arthroplasty (UKA) compared to total knee arthroplasty (TKA)?

. Increased blood loss.
. Higher risk of deep vein thrombosis.
. Greater postoperative pain.
. Higher rate of revision surgery.
. Longer recovery time.

Correct Answer & Explanation

. Higher rate of revision surgery.

Explanation

The most significant disadvantage of unicompartmental knee arthroplasty (UKA) compared to total knee arthroplasty (TKA) is a higher rate of revision surgery. While UKA offers advantages like less bone resection, faster recovery, and better range of motion for carefully selected patients, it has a higher cumulative revision rate, often due to progression of osteoarthritis in the unreplaced compartments, aseptic loosening, or technical issues. The other options (blood loss, DVT, pain, recovery time) are generally either comparable or oftenbetterwith UKA in the short term.

Question 4586

Topic: 3. Adult Reconstruction (Hip & Knee)
A 58-year-old male with a history of chronic alcoholism and pancreatitis develops progressive bilateral hip pain. Radiographs reveal patchy sclerosis and lucency in both femoral heads, with a subchondral crescent sign. What is the most appropriate treatment at this stage?
. Core decompression of the femoral head.
. Total hip arthroplasty (THA).
. Non-operative management with crutches and NSAIDs.
. Intertrochanteric osteotomy.
. Hemiarthroplasty.

Correct Answer & Explanation

. Total hip arthroplasty (THA).

Explanation

The patient's history (chronic alcoholism, pancreatitis) and radiographic findings (patchy sclerosis/lucency, subchondral crescent sign) are classic for osteonecrosis (avascular necrosis, AVN) of the femoral head. The presence of a subchondral crescent sign indicates collapse of the femoral head, which signifies a Ficat Stage III or IV lesion. At this stage, the joint surface has collapsed, and total hip arthroplasty (THA) is typically the most appropriate treatment to relieve pain and restore function. Core decompression is effective for pre-collapse (Ficat I/II) stages. Non-operative management is unlikely to provide lasting relief with collapse. Intertrochanteric osteotomy is a joint-preserving procedure for early-stage AVN, but less effective once collapse occurs. Hemiarthroplasty is less commonly used for AVN than THA.

Question 4587

Topic: 3. Adult Reconstruction (Hip & Knee)

A patient undergoing an anterior total hip arthroplasty is positioned supine. Which nerve is most susceptible to injury during positioning or retraction, especially with hyperextension and external rotation of the hip?

. Sciatic nerve.
. Femoral nerve.
. Obturator nerve.
. Lateral femoral cutaneous nerve.
. Peroneal nerve.

Correct Answer & Explanation

. Lateral femoral cutaneous nerve.

Explanation

The lateral femoral cutaneous nerve (LFCN) is particularly susceptible to injury during positioning and retraction in the direct anterior approach to total hip arthroplasty. It is a sensory nerve that exits the pelvis near the anterior superior iliac spine (ASIS) and can be compressed or stretched with hip hyperextension, external rotation, or direct pressure from retractors, leading to meralgia paresthetica (numbness/pain in the lateral thigh). The sciatic nerve is posterior. The femoral and obturator nerves are more medial and deep, though still at risk. The peroneal nerve is typically at risk around the fibular head.

Question 4588

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following interventions is most effective for preventing venous thromboembolism (VTE) in a high-risk orthopedic patient undergoing total knee arthroplasty?

. Early ambulation alone.
. Graduated compression stockings.
. Intermittent pneumatic compression devices (IPCDs).
. Pharmacological prophylaxis with anticoagulants.
. Sequential compression devices (SCDs).

Correct Answer & Explanation

. Pharmacological prophylaxis with anticoagulants.

Explanation

For high-risk orthopedic patients undergoing major surgery like total knee arthroplasty, pharmacological prophylaxis with anticoagulants (e.g., LMWH, factor Xa inhibitors, warfarin) is the most effective single intervention for preventing VTE (deep vein thrombosis and pulmonary embolism). While early ambulation, graduated compression stockings, and intermittent pneumatic compression devices are important adjuncts, they are generally considered insufficient alone for high-risk patients. SCDs are a type of IPCD. Current guidelines often recommend a combination of pharmacological and mechanical prophylaxis.

Question 4589

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old male undergoes a total hip arthroplasty. Four weeks post-operatively, he develops fever, hip pain, and warmth. ESR and CRP are elevated. He also reports urinary frequency and dysuria, and a urine culture is positive for Staphylococcus aureus. What is the most likely pathway for the periprosthetic joint infection?

. Intraoperative contamination during surgery.
. Hematogenous spread from the urinary tract infection.
. Direct inoculation from a skin infection.
. Lymphatic spread from a distant focus.
. Superficial wound infection progressing to deep infection.

Correct Answer & Explanation

. Hematogenous spread from the urinary tract infection.

Explanation

Hematogenous spread from a distant source of infection, such as a urinary tract infection (UTI), is a well-recognized cause of late periprosthetic joint infection (PJI). In this scenario, the presence of a positive urine culture for Staphylococcus aureus (a common cause of both UTIs and PJI) along with systemic signs of infection and a painful, warm hip, strongly suggests that the UTI is the source of the PJI. While intraoperative contamination, direct inoculation, and superficial wound infections are all possible causes, the timing (4 weeks post-op) and the documented UTI point strongly to hematogenous spread. Lymphatic spread is a less common pathway for PJI.

Question 4590

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old male with a history of chronic obstructive pulmonary disease (COPD) and long-term corticosteroid use is undergoing an elective total hip arthroplasty. What is the most critical perioperative pulmonary management strategy to reduce postoperative complications?

. Routine prophylactic antibiotics.
. Aggressive bronchodilator therapy postoperatively.
. Preoperative optimization of lung function and early postoperative mobilization.
. Strict fluid restriction to prevent pulmonary edema.
. Prolonged postoperative mechanical ventilation.

Correct Answer & Explanation

. Preoperative optimization of lung function and early postoperative mobilization.

Explanation

For patients with significant pulmonary comorbidities like COPD, preoperative optimization of lung function (e.g., smoking cessation, bronchodilators, steroids if indicated, treatment of infections) is crucial. Combined with early postoperative mobilization, deep breathing exercises, and incentive spirometry, these strategies significantly reduce the risk of postoperative pulmonary complications such as atelectasis, pneumonia, and respiratory failure. While bronchodilators may be part of the regimen, aggressive use without optimization is not the primary strategy. Prophylactic antibiotics are for infection, not primary pulmonary management. Fluid restriction is generally not recommended as it can lead to dehydration. Prolonged mechanical ventilation is a last resort, not a preventative strategy.

Question 4591

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following is considered a relative contraindication to total knee arthroplasty?

. Age greater than 80 years
. Obesity (BMI > 40)
. Active knee infection
. Anterior cruciate ligament deficiency
. Rheumatoid arthritis

Correct Answer & Explanation

. Active knee infection

Explanation

Active knee infection is an absolute contraindication to total knee arthroplasty due to the high risk of periprosthetic joint infection. Obesity (BMI > 40) is a relative contraindication due to increased surgical risks and potential for poorer outcomes, but not an absolute one. Age is generally not a contraindication itself, but rather the patient's physiological status and comorbidities are considered. ACL deficiency is common in patients undergoing TKA for OA and is typically addressed by the prosthesis design. Rheumatoid arthritis is an indication for TKA.

Question 4592

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following factors is most strongly associated with an increased risk of revision total hip arthroplasty due to aseptic loosening?

. Female gender
. Younger patient age at primary surgery
. Ceramic-on-ceramic bearing surfaces
. Use of cemented femoral components
. Obesity

Correct Answer & Explanation

. Younger patient age at primary surgery

Explanation

Younger patient age at primary total hip arthroplasty is strongly associated with an increased risk of revision due to aseptic loosening, primarily because a longer life expectancy means more activity and a longer duration for wear and biologic response to occur, leading to osteolysis and loosening. While obesity can increase the risk of complications, and bearing surfaces can influence wear, age is a dominant factor for the long-term risk of aseptic loosening. Cemented femoral components have shown excellent long-term results in appropriate patient populations.

Question 4593

Topic: 3. Adult Reconstruction (Hip & Knee)

Which surgical approach for total hip arthroplasty is known for having the lowest rate of dislocation?

. Anterior approach
. Posterior approach
. Anterolateral approach
. Direct lateral approach
. Trochanteric osteotomy approach

Correct Answer & Explanation

. Anterior approach

Explanation

The anterior approach to total hip arthroplasty is often touted for its muscle-sparing nature (working between muscle planes) and typically has a reported lower rate of post-operative dislocation compared to the posterior approach, which involves detachment of the short external rotators. While other approaches also have good results, the anterior approach is frequently associated with a lower dislocation risk in the hands of experienced surgeons.

Question 4594

Topic: 3. Adult Reconstruction (Hip & Knee)

What is the definitive treatment for symptomatic synovial chondromatosis of the knee?

. NSAIDs and physical therapy
. Intra-articular corticosteroid injections
. Arthroscopic removal of loose bodies and synovectomy
. Total knee arthroplasty
. Observation

Correct Answer & Explanation

. Arthroscopic removal of loose bodies and synovectomy

Explanation

Synovial chondromatosis is a benign condition characterized by the formation of cartilaginous nodules within the synovial membrane, which can detach and form loose bodies within the joint. For symptomatic cases, the definitive treatment is arthroscopic removal of the loose bodies and partial or complete synovectomy to remove the source of the chondromas and prevent recurrence. Conservative measures are usually ineffective, and TKA is only considered for end-stage arthritis caused by the condition.

Question 4595

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following is the most sensitive imaging modality for detecting early avascular necrosis (AVN) of the femoral head?

. Plain radiographs
. CT scan
. MRI
. Bone scintigraphy
. Ultrasound

Correct Answer & Explanation

. MRI

Explanation

MRI is the most sensitive imaging modality for detecting early avascular necrosis (AVN) of the femoral head. It can identify changes in bone marrow edema and signal intensity patterns before changes become apparent on plain radiographs (which may be normal for several months after symptom onset). CT scans are good for bone detail but less sensitive than MRI for early AVN. Bone scintigraphy can show increased uptake but is less specific than MRI. Ultrasound is not used for AVN diagnosis.

Question 4596

Topic: 3. Adult Reconstruction (Hip & Knee)

What is the 'circle of Willis' equivalent for the hip joint, providing crucial vascular supply to the femoral head?

. Medial circumflex femoral artery
. Lateral circumflex femoral artery
. Obturator artery
. Superior gluteal artery
. Inferior gluteal artery

Correct Answer & Explanation

. Medial circumflex femoral artery

Explanation

The medial circumflex femoral artery (MCFA) is the most critical artery supplying the femoral head, particularly its lateral epiphyseal branch. Disruption of the MCFA, often seen in femoral neck fractures, is a major contributor to avascular necrosis. While other arteries (lateral circumflex femoral, obturator) contribute, the MCFA is considered the primary and most important. There isn't a 'circle of Willis' equivalent for the hip in the same anastomotic sense, but the MCFA's role is dominant.

Question 4597

Topic: 3. Adult Reconstruction (Hip & Knee)
A 70-year-old patient undergoes an elective total knee arthroplasty. On post-operative day 3, he develops confusion, new onset atrial fibrillation, and a core temperature of 38.5°C. His laboratory results show a lactate of 3.2 mmol/L. Which of the following best describes the patient's current clinical state according to current sepsis definitions?
. SIRS
. Sepsis
. Septic Shock
. Simple post-operative fever
. Delirium due to anesthesia

Correct Answer & Explanation

. Sepsis

Explanation

The patient exhibits signs of Systemic Inflammatory Response Syndrome (SIRS) (fever, new onset atrial fibrillation potentially reflecting tachycardia, confusion). Crucially, the presence of new organ dysfunction (confusion, new onset atrial fibrillation) and an elevated lactate (suggesting tissue hypoperfusion/dysfunction) in the context of presumed infection (post-operative period, potential for surgical site infection) meets the criteria for Sepsis (life-threatening organ dysfunction caused by a dysregulated host response to infection). Septic shock would require persistent hypotension despite adequate fluid resuscitation, necessitating vasopressors to maintain MAP ≥65 mmHg, and a lactate >2 mmol/L. While he has elevated lactate, persistent hypotension requiring vasopressors is not specified.

Question 4598

Topic: 3. Adult Reconstruction (Hip & Knee)

A patient undergoing hip arthroplasty develops a sudden fever, chills, and hypotension intraoperatively. Which of the following is the most important immediate step in managing suspected intraoperative sepsis or septic shock?

. Administer a bolus of an anti-pyretic
. Obtain an immediate blood culture and initiate broad-spectrum antibiotics
. Increase anesthetic depth to stabilize vitals
. Administer a large bolus of crystalloids and vasopressors if blood pressure remains low
. Continue with the surgical procedure to minimize operating time

Correct Answer & Explanation

. Administer a large bolus of crystalloids and vasopressors if blood pressure remains low

Explanation

In suspected intraoperative sepsis/septic shock, the immediate priority is to support hemodynamics and identify/treat the infection. After obtaining cultures, prompt administration of crystalloids and vasopressors (if needed) to maintain MAP is crucial. Broad-spectrum antibiotics should be started as soon as cultures are drawn. Anti-pyretics address a symptom, not the underlying problem. Increasing anesthetic depth could worsen hypotension. Continuing the procedure without addressing the systemic crisis is dangerous. The combination of fluid and vasopressor support is the most critical immediate step to prevent irreversible organ damage.

Question 4599

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old female with a history of cirrhosis (Child-Pugh Class B) undergoes a complex revision total hip arthroplasty. On post-operative day 2, she develops abdominal pain, fever, and altered mental status. Her INR is 2.5, and her bilirubin is 3.0 mg/dL. Her baseline INR was 1.4 and bilirubin 1.8 mg/dL. Which type of infection is a significant concern in patients with cirrhosis developing sepsis?

. Staphylococcus epidermidis prosthetic joint infection
. Streptococcus pneumoniae pneumonia
. Spontaneous bacterial peritonitis
. Clostridium difficile colitis
. Urinary tract infection by Enterococcus

Correct Answer & Explanation

. Spontaneous bacterial peritonitis

Explanation

Patients with cirrhosis, especially those with ascites, are at high risk for spontaneous bacterial peritonitis (SBP). This infection presents with fever, abdominal pain, altered mental status, and worsening liver function (as indicated by rising INR and bilirubin). While the patient underwent hip surgery, the abdominal symptoms, liver dysfunction, and history of cirrhosis strongly point to SBP as a significant concern in this context, even if other infections are possible. The question specifically asks about infections a patient with cirrhosis is prone to.

Question 4600

Topic: 3. Adult Reconstruction (Hip & Knee)

Which pathogen is most commonly associated with early onset (within 3 months) prosthetic joint infection (PJI) following total joint arthroplasty, often leading to rapid sepsis if untreated?

. Coagulase-negative Staphylococci (e.g., S. epidermidis)
. Propionibacterium acnes
. Staphylococcus aureus (MSSA/MRSA)
. Anaerobic bacteria (e.g., Peptostreptococcus)
. Candida species

Correct Answer & Explanation

. Staphylococcus aureus (MSSA/MRSA)

Explanation

Staphylococcus aureus (both MSSA and MRSA) is the most common pathogen associated with early-onset prosthetic joint infections (within the first 3 months) and often presents with more acute and aggressive symptoms, including rapid progression to sepsis. Coagulase-negative Staphylococci (like S. epidermidis) are more commonly associated with delayed-onset PJI (3-12 months) and a more indolent course. P. acnes is typically associated with shoulder PJI. Anaerobes and Candida are less common overall causes of PJI.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page