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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 154 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 3061

Topic: Total Hip Arthroplasty (THA)

A 6-year-old boy sustains a spiral midshaft femur fracture. He is managed with a spica cast. Two years later, his parents are concerned about a leg length discrepancy. Which of the following is the most expected outcome regarding limb length after this injury?

. The fractured femur will be 1 to 2 cm shorter than the uninjured side
. The fractured femur will be 1 to 2 cm longer than the uninjured side
. The uninjured femur will undergo compensatory overgrowth
. There will be a 3 to 4 cm overgrowth of the fractured femur
. Leg lengths will remain perfectly equal without any overgrowth

Correct Answer & Explanation

. The fractured femur will be 1 to 2 cm shorter than the uninjured side

Explanation

Children between 2 and 10 years of age typically experience an overgrowth phenomenon following a femur fracture, usually resulting in 1 to 2 cm of overgrowth of the fractured limb within the first 2 years.

Question 3062

Topic: 3. Adult Reconstruction (Hip & Knee)

A 7-year-old boy with spastic quadriplegic cerebral palsy has progressive lateral subluxation of the right hip. Radiographs reveal a migration percentage of 50%, a neck-shaft angle of 155 degrees, and an acetabular index of 35 degrees. What is the most appropriate definitive management?

. Adductor tenotomy and observation
. Proximal femoral varus derotational osteotomy (VDRO) alone
. Proximal femoral VDRO combined with a pelvic osteotomy
. Shelf acetabuloplasty alone
. Total hip arthroplasty

Correct Answer & Explanation

. Adductor tenotomy and observation

Explanation

In older children (typically >4 years) with spastic cerebral palsy and significant hip subluxation (migration percentage >40%), both femoral dysplasia (coxa valga and excessive anteversion) and acetabular dysplasia are usually present. Soft tissue releases alone are inadequate. Comprehensive bony reconstruction with a proximal femoral varus derotational osteotomy (VDRO) and a concomitant pelvic osteotomy (e.g., Dega or San Diego) is required to achieve and maintain concentric reduction.

Question 3063

Topic: 3. Adult Reconstruction (Hip & Knee)

An 8-year-old boy with spastic quadriplegic cerebral palsy is found to have a migration percentage of 45% on his anteroposterior pelvis radiograph. He has pain with diaper changes and limited hip abduction. What is the most appropriate management?

. Observation and repeat radiographs in 1 year
. Adductor and iliopsoas tenotomies alone
. Varus derotational osteotomy (VDRO) of the proximal femur and pelvic osteotomy
. Total hip arthroplasty
. Proximal femoral resection (Girdlestone procedure)

Correct Answer & Explanation

. Observation and repeat radiographs in 1 year

Explanation

In children with cerebral palsy, hip subluxation is a common problem related to muscle imbalance. A migration percentage of >40-50% with progressive deformity or pain indicates a high risk of complete dislocation and joint degeneration. Soft tissue releases alone (adductor/iliopsoas tenotomies) are generally ineffective once the migration percentage exceeds 40% and bony changes are present. The gold standard treatment involves a bony reconstruction: a proximal femoral varus derotational osteotomy (VDRO) combined with a pelvic osteotomy (e.g., Dega or San Diego) to restore joint congruity and contain the femoral head.

Question 3064

Topic: 3. Adult Reconstruction (Hip & Knee)

A homebound 75-year-old woman with diabetes mellitus has had progressive left knee pain and swelling for the past 6 weeks. She is febrile with a temperature of 103 degrees F (39.5 degrees C). History reveals that she underwent arthroplasty 5 years ago. Examination shows passive range of motion of 0 to 100 degrees with no active extension. Knee aspiration reveals purulent fluid with a Gram stain showing gram-negative rods. A radiograph is shown in Figure 27. In addition to IV antibiotics, which of the following management options offers the best chance of a successful outcome?

. Incision and drainage with repair of the extensor mechanism
. Removal of components and delayed revision knee arthroplasty with an allograft extensor mechanism
. Removal of components and immediate exchange revision total knee arthroplasty
. Removal of components and delayed knee arthrodesis
. Removal of components and delayed revision knee arthroplasty with extensor mechanism repair

Correct Answer & Explanation

. Incision and drainage with repair of the extensor mechanism

Explanation

The patient has an infected total knee arthroplasty and an interrupted extensor mechanism. A late infection of a total knee arthroplasty in a patient with diabetes mellitus and a virulent organism requires removal of the components, debridement, antibiotic spacers, and surveillance to ensure eradication of the infection. Reconstruction of an incompetent extensor mechanism in an infected knee is extremely unlikely to be successful. Arthrodesis is the procedure of choice if a revision total knee arthroplasty is not likely to succeed. Resection arthroplasty is recommended only as a long-term solution if the patient is medically unable to undergo further surgery. Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgery, 2002, pp 513-536.

Question 3065

Topic: 3. Adult Reconstruction (Hip & Knee)

A 45-year-old man is brought to the emergency department after a dashboard injury. Radiographs reveal a posterior hip dislocation associated with a femoral head fracture extending cephalad to the fovea capitis. According to the Pipkin classification, what is the most appropriate definitive management for the femoral head injury?

. Closed reduction and spica casting for 6 weeks
. Excision of the fractured femoral head fragment
. Open reduction and internal fixation of the femoral head
. Primary total hip arthroplasty
. Hemiarthroplasty

Correct Answer & Explanation

. Closed reduction and spica casting for 6 weeks

Explanation

This is a Pipkin Type II fracture, which involves the weight-bearing portion of the femoral head (cephalad to the fovea). Because it involves the weight-bearing dome, open reduction and internal fixation is indicated to restore joint congruity and minimize post-traumatic arthrosis.

Question 3066

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old community-ambulating woman with no significant medical comorbidities sustains a displaced, acute intracapsular femoral neck fracture. Based on current literature, what is the primary advantage of treating this patient with a total hip arthroplasty (THA) compared to a hemiarthroplasty?

. Lower risk of postoperative dislocation
. Decreased surgical time and blood loss
. Lower long-term reoperation rate and improved functional outcomes
. Lower risk of perioperative mortality
. Reduced risk of periprosthetic joint infection

Correct Answer & Explanation

. Lower risk of postoperative dislocation

Explanation

In active, healthy, independent elderly patients with displaced femoral neck fractures, THA provides superior long-term functional scores (e.g., Harris Hip Score) and significantly lower reoperation rates compared to hemiarthroplasty. Hemiarthroplasty carries a lower dislocation risk but higher rates of subsequent acetabular erosion.

Question 3067

Topic: 3. Adult Reconstruction (Hip & Knee)

A 22-year-old athlete presents with an acute anterior hip dislocation following a rugby tackle. To minimize the risk of osteonecrosis of the femoral head, closed reduction should ideally be performed within what maximum timeframe from the time of injury?

. 6 hours
. 12 hours
. 24 hours
. 48 hours
. Time to reduction does not affect osteonecrosis risk in anterior dislocations

Correct Answer & Explanation

. 6 hours

Explanation

Urgent closed reduction of hip dislocations is critical, and performing it within 6 hours of injury is widely considered the standard of care to significantly reduce the risk of avascular necrosis (osteonecrosis) of the femoral head.

Question 3068

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old man undergoes successful closed reduction of a posterior hip dislocation in the emergency department. Post-reduction anteroposterior pelvis radiographs demonstrate an asymmetric widening of the medial joint space on the injured side. What is the most appropriate next step in management?

. Application of a hip spica cast
. Computed tomography (ct) scan of the pelvis
. Immediate open reduction via an anterior approach
. Immediate total hip arthroplasty
. Non-weight-bearing mobilization with physical therapy

Correct Answer & Explanation

. Application of a hip spica cast

Explanation

Asymmetric widening of the joint space after reduction of a hip dislocation strongly suggests an incarcerated osteochondral fragment or soft tissue interposition. A CT scan is mandatory to identify the offending structure and evaluate for associated acetabular or femoral head fractures prior to surgical clearance.

Question 3069

Topic: Total Hip Arthroplasty (THA)

Which anatomic structure is most frequently implicated in blocking the successful closed reduction of an acute posterior hip dislocation?

. Iliopsoas tendon
. Gluteus maximus muscle
. Rectus femoris tendon
. Buttonholing through the posterior capsule or piriformis
. Ligamentum teres

Correct Answer & Explanation

. Iliopsoas tendon

Explanation

Irreducible posterior hip dislocations are most commonly caused by the femoral head 'buttonholing' through the posterior hip capsule, the piriformis, or the short external rotators. An open reduction (usually via a posterior approach) is required to extricate the head.

Question 3070

Topic: Total Hip Arthroplasty (THA)

A healthy, independent 70-year-old woman sustains a displaced femoral neck fracture. She is an avid golfer and walks two miles daily. Comparing total hip arthroplasty (THA) to bipolar hemiarthroplasty for this specific patient, THA is associated with which of the following?

. Higher dislocation rate and lower reoperation rate
. Lower dislocation rate and lower reoperation rate
. Higher dislocation rate and higher reoperation rate
. Lower dislocation rate and higher reoperation rate
. Equivalent dislocation and reoperation rates

Correct Answer & Explanation

. Higher dislocation rate and lower reoperation rate

Explanation

In active, independent elderly patients with displaced femoral neck fractures, THA provides superior functional outcomes and lower long-term reoperation rates compared to hemiarthroplasty. However, THA does carry a higher immediate postoperative risk of dislocation.

Question 3071

Topic: 3. Adult Reconstruction (Hip & Knee)

A healthy, independent, 72-year-old community-dwelling man who regularly plays golf sustains a displaced femoral neck fracture. He is discussing surgical options, specifically hemiarthroplasty versus total hip arthroplasty (THA). What is a well-documented long-term advantage of THA in this specific demographic?

. Lower postoperative dislocation rate
. Lower rate of future reoperation
. Shorter total operative time
. Decreased intraoperative blood loss
. Reduced risk of early periprosthetic joint infection

Correct Answer & Explanation

. Lower postoperative dislocation rate

Explanation

In active, healthy, older adults with displaced femoral neck fractures, total hip arthroplasty yields better long-term functional scores and a lower reoperation rate compared to hemiarthroplasty. However, THA is associated with longer surgical times, increased blood loss, and a higher risk of postoperative dislocation.

Question 3072

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following vessels provides the predominant blood supply to the adult femoral head, placing it at the greatest risk for avascular necrosis following a displaced femoral neck fracture?

. Artery of the ligamentum teres
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Artery of the ligamentum teres

Explanation

The medial femoral circumflex artery (MFCA), specifically its lateral epiphyseal branches, provides the primary blood supply to the adult femoral head. The artery of the ligamentum teres provides a negligible supply in adults.

Question 3073

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old man sustains a traumatic posterior hip dislocation without associated fractures. To minimize the risk of developing avascular necrosis of the femoral head, a closed reduction should ideally be successfully performed within what maximum timeframe?

. 1 hour
. 6 hours
. 12 hours
. 24 hours
. 48 hours

Correct Answer & Explanation

. 1 hour

Explanation

Hip dislocations are an orthopedic emergency. Reduction within 6 hours has been shown to significantly decrease the risk of avascular necrosis and long-term joint degeneration.

Question 3074

Topic: Total Hip Arthroplasty (THA)

A 33-year-old man undergoes a successful closed reduction of a traumatic posterior hip dislocation. The post-reduction CT scan demonstrates a congruent hip joint without intra-articular step-off, but reveals a 2 mm osteochondral fragment in the inferior, dependent aspect of the joint. The patient has a full, unrestricted range of motion. What is the most appropriate management?

. Immediate open arthrotomy via a posterior approach for fragment excision
. Immediate arthroscopic fragment excision
. Observation and conservative management with progressive weight-bearing
. Skeletal traction for 6 weeks
. Spica casting for 4 weeks

Correct Answer & Explanation

. Immediate open arthrotomy via a posterior approach for fragment excision

Explanation

Small, non-weight-bearing, dependent osteochondral fragments (<2-3 mm) that do not block motion and occur in the setting of a congruent joint can safely be observed. Operative intervention is indicated for large fragments, incarcerated fragments causing a noncongruent joint, or mechanical blocks to motion.

Question 3075

Topic: 3. Adult Reconstruction (Hip & Knee)

An 80-year-old woman with end-stage dementia who is chronically bedbound presents with a closed, displaced femoral neck fracture after rolling out of bed. The family requests the least invasive approach focused solely on pain control. What is an acceptable orthopedic management strategy for this specific patient profile?

. Immediate total hip arthroplasty
. Prophylactic sliding hip screw fixation
. Non-operative management with early mobilization to a chair
. Application of a hip spica cast
. Prolonged skeletal traction via a distal femoral pin

Correct Answer & Explanation

. Immediate total hip arthroplasty

Explanation

In chronically bedbound, non-ambulatory patients with severe dementia and very high surgical risk, non-operative management of a displaced femoral neck fracture is an acceptable, palliative option. The focus is on pain control and mobilization to a chair to prevent cardiopulmonary complications.

Question 3076

Topic: 3. Adult Reconstruction (Hip & Knee)

In a 30-year-old patient with an acute, displaced, transcervical femoral neck fracture, what is the most appropriate surgical management?

. Hemiarthroplasty
. Total hip arthroplasty
. Closed reduction and percutaneous pinning with three parallel screws
. Urgent open reduction and internal fixation
. Nonoperative management with skeletal traction

Correct Answer & Explanation

. Hemiarthroplasty

Explanation

Displaced femoral neck fractures in young patients are orthopedic emergencies requiring urgent open (or closed, if anatomic reduction is achievable) reduction and internal fixation. This preserves the native hip and minimizes the risks of avascular necrosis and nonunion.

Question 3077

Topic: Total Hip Arthroplasty (THA)

During a posterior approach to the hip for a displaced femoral neck fracture, care must be taken to protect the primary blood supply to the femoral head. Which artery provides the majority of the blood supply to the adult femoral head?

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

Correct Answer & Explanation

. Inferior gluteal artery

Explanation

The medial femoral circumflex artery (MFCA), specifically its lateral epiphyseal branches, provides the predominant blood supply to the adult femoral head. It courses posterior to the obturator externus and anterior to the short external rotators.

Question 3078

Topic: Total Hip Arthroplasty (THA)

A healthy, community-ambulating 70-year-old woman sustains a displaced femoral neck fracture. When comparing total hip arthroplasty (THA) to bipolar hemiarthroplasty for her definitive treatment, THA is associated with:

. Lower risk of postoperative dislocation
. Decreased operative time and blood loss
. Lower incidence of acetabular wear and lower reoperation rates
. Higher rate of deep infection
. Decreased functional outcome scores at 5 years

Correct Answer & Explanation

. Lower risk of postoperative dislocation

Explanation

In active elderly patients with displaced femoral neck fractures, THA provides better long-term functional outcomes and lower reoperation rates (due to eliminating acetabular wear) compared to hemiarthroplasty. However, THA does carry a higher risk of postoperative dislocation.

Question 3079

Topic: 3. Adult Reconstruction (Hip & Knee)
A 35-year-old healthy male sustains a vertically oriented, displaced femoral neck fracture (Pauwels III). Which of the following fixation constructs provides the most biomechanically stable fixation for this specific fracture pattern?
. Three parallel cannulated screws
. A sliding hip screw (SHS) with an anti-rotation screw
. A fully threaded cancellous screw construct
. Cemented hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. A sliding hip screw (SHS) with an anti-rotation screw

Explanation

Pauwels III femoral neck fractures have a vertical orientation, subjecting the fracture to high shear forces. A fixed-angle construct, such as a sliding hip screw combined with an anti-rotation screw, provides superior biomechanical stability compared to multiple cannulated screws.

Question 3080

Topic: Total Hip Arthroplasty (THA)

A highly active 68-year-old male presents with a displaced femoral neck fracture. He is medically optimized and a decision is made between total hip arthroplasty (THA) and hemiarthroplasty. According to current literature, which of the following is true regarding THA compared to hemiarthroplasty in this patient population?

. THA is associated with a higher dislocation rate.
. THA has a higher long-term revision rate.
. Hemiarthroplasty yields superior Harris Hip Scores.
. Hemiarthroplasty is associated with lower mortality at 30 days.
. THA results in significantly faster surgical times.

Correct Answer & Explanation

. THA is associated with a higher dislocation rate.

Explanation

In active, healthy older patients, THA for displaced femoral neck fractures provides better functional outcomes and lower revision rates than hemiarthroplasty. However, it is consistently associated with a higher risk of postoperative dislocation.

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