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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 2 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 21

Topic: Total Hip Arthroplasty (THA)

Which of the following statements regarding the treatment of thoracic disk herniations is true:

. The majority of patients can be treated nonoperatively.
. Surgical decompression is necessary in most cases.
. Laminectomy is the surgical procedure of choice.
. The anterior transthoracic approach is used for T1-T4 lesions.
. C ostotransversectomy is used for large central calcified herniations.

Correct Answer & Explanation

. The majority of patients can be treated nonoperatively.

Explanation

The majority (75%) of patients with thoracic disk herniations may be managed nonoperatively. Surgical procedures must adequately decompress the involved nerve root. Posterior approach by laminectomy is usually not adequate, and costotransversectomy is not effective for large central calcified herniations (an anterior approach is preferred). The anterior transthoracic approach is effective for T5-T12 lateral and anterior disk herniations.

Question 22

Topic: 3. Adult Reconstruction (Hip & Knee)

A 40-year-old recent immigrant presents with severe back pain, fevers, and a progressive gibbus deformity. Imaging reveals severe osteolysis of the T8 and T9 anterior vertebral bodies with relative preservation of the intervening intervertebral disc space. What is the most likely responsible pathogen?

. Staphylococcus aureus
. Streptococcus pneumoniae
. Mycobacterium tuberculosis
. Pseudomonas aeruginosa
. Brucella melitensis

Correct Answer & Explanation

. Mycobacterium tuberculosis

Explanation

Mycobacterium tuberculosis (Pott's disease) characteristically destroys the anterior vertebral bodies leading to collapse and a sharp kyphosis (gibbus deformity). Unlike pyogenic infections, tuberculous spondylitis typically spares or shows delayed destruction of the intervertebral disc space.

Question 23

Topic: Total Hip Arthroplasty (THA)
A 48-year-old man presents with a closed head injury requiring intubation and isolated bilateral facet dislocation. The next appropriate step is:
. Closed reduction with axial traction with Gardner-Wells tongs
. Posterior open reduction and posterior cervical plating
. Emergent magnetic resonance imaging
. Neurostabilization until the patient's neurologic status improves
. Administration of Decadron (Merck & Co., West Point, Pa.) 10 mg/hr intravenously

Correct Answer & Explanation

. Emergent magnetic resonance imaging

Explanation

The patient has a severe closed head injury and is unable to tolerate close reduction maneuvers with Gardner-Wells tongs. Emergent magnetic resonance imaging should be obtained to evaluate the potential presence of a disk herniation at the dislocation. Should a disk herniation be present, anterior approach and diskectomy should be performed prior to reduction maneuvers.

Question 24

Topic: 3. Adult Reconstruction (Hip & Knee)
A 9-year-old girl sustains a femoral neck fracture as a result of a fall. What is her risk of avascular necrosis?
. 95%
. 75%
. 50%
. 25%
. 5%

Correct Answer & Explanation

. 25%

Explanation

This patient has a displaced basicervical fracture of the femur that is classified as Delbet type III. The risk of avascular necrosis is approximately 20% to 25%. She should be monitored closely for the first 12 to 18 months after injury for this complication.

Question 25

Topic: 3. Adult Reconstruction (Hip & Knee)

A 6-year-old boy presents with a 3-month history of medial midfoot pain. Based on his radiograph (Slide), which of the following is the correct diagnosis:

. Kohler s disease
. Panner s disease
. Eosinophilic granuloma
. Accessory navicular
. Freiberg s disorder

Correct Answer & Explanation

. Kohler s disease

Explanation

This child has avascular necrosis of the tarsal navicular. This is an idiopathic phenomenon more common in boys of this age than girls. The condition responds to rest and orthotics or cast immobilization. The navicular revascularizes over the ensuing year.

Question 26

Topic: 3. Adult Reconstruction (Hip & Knee)

In a 6-year-old child with spastic quadriplegic cerebral palsy, routine hip surveillance radiographs show a Reimers migration index of 45%. Which of the following is the most appropriate management?

. Observation and repeat radiograph in 1 year
. Botulinum toxin injection to the adductors
. Adductor tenotomy alone
. Varus derotational osteotomy (VDRO) of the proximal femur with or without pelvic osteotomy
. Total hip arthroplasty

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) of the proximal femur with or without pelvic osteotomy

Explanation

A Reimers migration index >40% indicates significant hip subluxation in CP. Bony reconstructive surgery (VDRO and possibly pelvic osteotomy) is required to restore joint congruency and prevent dislocation.

Question 27

Topic: 3. Adult Reconstruction (Hip & Knee)

A 3-year-old girl presents with progressive bilateral genu varum. Radiographs show a prominent metaphyseal beak and a metaphyseal-diaphyseal angle of 18 degrees. What is the recommended treatment?

. Observation only
. Knee-ankle-foot orthoses (KAFOs)
. Proximal tibial valgus osteotomy
. Hemiepiphysiodesis of the medial proximal tibia
. Total knee arthroplasty

Correct Answer & Explanation

. Proximal tibial valgus osteotomy

Explanation

Infantile Blount disease with a metaphyseal-diaphyseal angle greater than 16 degrees is unlikely to resolve spontaneously. In a 3-year-old, proximal tibial valgus osteotomy is the surgical treatment of choice.

Question 28

Topic: Total Hip Arthroplasty (THA)

A 10-year-old girl is predicted to have a 3.5 cm leg length discrepancy at skeletal maturity, with the right leg being shorter. She and her parents desire a minimal surgical intervention. What is the most appropriate management?

. Right femoral lengthening using a circular frame
. Left proximal tibial hemiepiphysiodesis
. Left femoral and tibial epiphysiodesis
. Shoe lift only
. Right proximal femoral osteotomy

Correct Answer & Explanation

. Left femoral and tibial epiphysiodesis

Explanation

For a predicted leg length discrepancy of 2-5 cm at maturity, an epiphysiodesis of the longer limb is the standard and least invasive surgical treatment. Discrepancies >5 cm generally require lengthening procedures.

Question 29

Topic: Total Hip Arthroplasty (THA)

A 5-year-old girl presents with an enlarged left lower extremity, varicose veins, and a port-wine stain extending from her thigh to her foot. No significant arteriovenous fistulas are noted. Which of the following is the most appropriate initial management for her projected 4 cm leg length discrepancy?

. Epiphysiodesis of the contralateral (unaffected) limb
. Epiphysiodesis of the affected limb
. Femoral lengthening of the affected limb using an external fixator
. Amputation of the affected limb
. Vascular bypass surgery

Correct Answer & Explanation

. Epiphysiodesis of the affected limb

Explanation

Klippel-Trenaunay syndrome involves capillary malformations, venous varicosities, and limb hypertrophy without high-flow AV fistulas. Management of the resulting limb length discrepancy typically involves appropriately timed epiphysiodesis of the hypertrophied (affected) limb.

Question 30

Topic: Total Hip Arthroplasty (THA)

A 4-year-old child presents with an enlarged left lower extremity, cutaneous port-wine stains, and prominent varicose veins. There is a 3 cm leg length discrepancy (left longer than right). What is the most appropriate initial management for the limb length inequality?

. Immediate tibial lengthening of the contralateral side
. Immediate femoral shortening of the affected side
. Prophylactic epiphysiodesis of the unaffected limb
. Shoe lift on the short side and observation
. Sclerotherapy of the vascular malformations to halt growth

Correct Answer & Explanation

. Shoe lift on the short side and observation

Explanation

Klippel-Trenaunay syndrome involves overgrowth of the affected limb. Initial management of the limb length discrepancy is conservative with a shoe lift and observation until skeletal maturity approaches or the discrepancy warrants epiphysiodesis.

Question 31

Topic: 3. Adult Reconstruction (Hip & Knee)

An 11-year-old girl presents with a limp. She has no history of trauma, infection, or neurologic disorder. She does not report any pain. Recommended treatment includes:

. Hip arthrodesis
. Uncemented total hip arthroplasty
. Cemented total hip arthroplasty
. Resurfacing hip arthroplasty
. No treatment

Correct Answer & Explanation

. No treatment

Explanation

This patient has untreated developmental dysplasia of the hip. Her limp cannot be eliminated. If she is not experiencing pain, then no treatment is indicated.

Question 32

Topic: 3. Adult Reconstruction (Hip & Knee)

When using a rigid intramedullary nail for a femoral shaft fracture in an adolescent with open physes, avoiding the piriformis fossa and instead utilizing a lateral trochanteric entry point primarily minimizes the risk of:

. Greater trochanteric apophysiodesis
. Coxa valga
. Avascular necrosis of the femoral head
. Leg length discrepancy
. Heterotopic ossification

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

The piriformis fossa entry point damages the ascending branch of the medial femoral circumflex artery in adolescents with open physes, leading to a high risk of avascular necrosis. A lateral trochanteric entry point avoids this critical vascular supply.

Question 33

Topic: 3. Adult Reconstruction (Hip & Knee)

A 12-year-old sustains a traumatic posterior hip dislocation during a motor vehicle accident. Closed reduction is delayed and performed 8 hours after the injury. What is the most devastating complication directly related to this delay?

. Sciatic nerve palsy
. Heterotopic ossification
. Chondrolysis
. Avascular necrosis of the femoral head
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

The risk of avascular necrosis (AVN) of the femoral head increases significantly if a hip dislocation is not reduced within 6 hours of injury. Urgent reduction is essential to restore blood flow.

Question 34

Topic: 3. Adult Reconstruction (Hip & Knee)
According to the Delbet classification, the risk of avascular necrosis is least with which of the following pediatric hip fractures?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type I

Explanation

The risk of avascular necrosis is highest with type I, followed by about equal rates for types II and III (approximately 15%). The risk of avascular necrosis is low for type IV, intertrochanteric fractures. Type I: Transphyseal; Type II: Transcervical; Type III: Basicervical; Type IV: Intertrochanteric.

Question 35

Topic: 3. Adult Reconstruction (Hip & Knee)

In analyzing coronal plane alignment of the lower extremity, the mechanical axis of the femur differs from its anatomical axis. In a typical normal adult, what is the approximate angle between the mechanical and anatomical axes of the femur?

. 0 degrees
. 3 degrees
. 7 degrees
. 12 degrees
. 15 degrees

Correct Answer & Explanation

. 7 degrees

Explanation

The anatomical axis of the femur lies approximately 7 degrees (usually 5-7 degrees) in valgus relative to its mechanical axis. This angle is vital for preoperative planning in deformity correction and arthroplasty.

Question 36

Topic: 3. Adult Reconstruction (Hip & Knee)

Schmorl's nodes are a common radiographic finding in Scheuermann's kyphosis. What do these nodes represent pathologically?

. Herniation of nucleus pulposus through the vertebral endplate into the adjacent vertebral body
. Osteoporotic micro-fractures of the anterior vertebral body
. Congenital failure of anterior vertebral body formation
. Ossification of the posterior longitudinal ligament
. Avascular necrosis of the vertebral body apex

Correct Answer & Explanation

. Herniation of nucleus pulposus through the vertebral endplate into the adjacent vertebral body

Explanation

Schmorl's nodes occur when the intervertebral disc (nucleus pulposus) herniates vertically through a weakened or defective cartilaginous endplate into the cancellous bone of the vertebral body.

Question 37

Topic: Total Hip Arthroplasty (THA)

Which part of the body is removed last in a posterior vertebral column resected via a posterior approach:

. The lamina
. The pedicles
. The anterior wall of the vertebral body
. The posterior vertebral cortex
. The transverse process

Correct Answer & Explanation

. The posterior vertebral cortex

Explanation

To protect and stabilize the neural elements, the posterior vertebral cortex is left intact to be resected last.

Question 38

Topic: 3. Adult Reconstruction (Hip & Knee)

An 8-year-old boy suffers a hip dislocation while playing tackle football. His hip is reduced by closed means, and he is immobilized in abduction for a month. Radiographs at that time demonstrate a normal appearance of the hip. You recommend:

. Discharge from follow-up
. Return to all sports and follow-up in 2 months
. No sports and return to clinic in 2 months
. Hip abduction orthosis
. Femoral varus osteotomy

Correct Answer & Explanation

. No sports and return to clinic in 2 months

Explanation

This patient may suffer avascular necrosis as a result of the dislocation. Avascular necrosis may not become evident until 1 year after the accident, so continued surveillance and protection are recommended.

Question 39

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following bearing surface combinations in total hip arthroplasty is most closely associated with the complication of "squeaking"?

. Ceramic-on-polyethylene
. Metal-on-polyethylene
. Ceramic-on-ceramic
. Metal-on-metal
. Oxinium-on-polyethylene

Correct Answer & Explanation

. Ceramic-on-ceramic

Explanation

Squeaking is a well-documented specific complication associated with ceramic-on-ceramic bearings. Risk factors include impingement, edge loading, and component malposition.

Question 40

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following preoperative deformities in a patient undergoing total knee arthroplasty (TKA) carries the highest risk of postoperative peroneal nerve palsy?

. Severe fixed varus deformity
. Severe fixed valgus deformity with a flexion contracture
. Severe recurvatum deformity
. Isolated patellofemoral arthritis
. Severe anterior bowing of the femur

Correct Answer & Explanation

. Severe fixed valgus deformity with a flexion contracture

Explanation

Severe fixed valgus deformities, especially when combined with a flexion contracture, place the peroneal nerve at significant risk of traction injury when the limb is surgically corrected to a neutral mechanical axis.

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