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8. Foot and Ankle MCQs

Practice Set 277 of 353

This practice set contains high-yield board review questions covering key concepts in 8. Foot and Ankle. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 5521

Topic: 8. Foot and Ankle

In a minimally invasive or percutaneous repair of a ruptured Achilles tendon, care must be taken to avoid iatrogenic injury to the sural nerve. What is the typical relationship of the sural nerve to the Achilles tendon?

. It runs strictly along the medial border of the tendon in the distal third of the leg.
. It crosses from medial to lateral approximately 5 cm proximal to the calcaneal insertion.
. It crosses the lateral border of the tendon approximately 10 cm proximal to its insertion.
. It runs exactly in the midline deep to the paratenon.
. It is positioned deep to the deep posterior compartment fascia near the flexor hallucis longus.

Correct Answer & Explanation

. It runs strictly along the medial border of the tendon in the distal third of the leg.

Explanation

The sural nerve typically crosses the lateral border of the Achilles tendon roughly 10 cm (average 9.8 cm) proximal to the calcaneal insertion. It proceeds distally along the lateral aspect of the hindfoot, making it vulnerable during lateral or percutaneous approaches to the Achilles tendon.

Question 5522

Topic: 8. Foot and Ankle

Which of the following is considered the primary and strongest stabilizer against valgus talar tilt within the superficial component of the deltoid ligament of the ankle?

. Anterior tibiotalar ligament
. Tibionavicular ligament
. Tibiocalcaneal ligament
. Posterior tibiotalar ligament
. Spring ligament

Correct Answer & Explanation

. Anterior tibiotalar ligament

Explanation

The deltoid ligament consists of superficial and deep layers. The superficial layer mainly resists valgus forces, with the tibiocalcaneal ligament being the thickest and strongest component of the superficial deltoid. The deep layer (deep anterior and posterior tibiotalar ligaments) is the primary restraint to lateral and anterior displacement of the talus.

Question 5523

Topic: 8. Foot and Ankle

The talus is highly prone to avascular necrosis following displaced fractures of the talar neck. Which artery provides the most significant vascular contribution to the body of the talus?

. Anterior tibial artery via branches to the head
. Peroneal artery via the lateral tarsal artery
. Artery of the tarsal canal (branch of posterior tibial artery)
. Artery of the sinus tarsi (branch of dorsalis pedis)
. Medial plantar artery

Correct Answer & Explanation

. Anterior tibial artery via branches to the head

Explanation

The most robust and significant blood supply to the body of the talus comes from the artery of the tarsal canal, which is a branch of the posterior tibial artery. It forms an anastomotic sling with the artery of the sinus tarsi and supplies the vast majority of the talar body.

Question 5524

Topic: 8. Foot and Ankle

The superficial peroneal nerve provides sensation to the majority of the dorsum of the foot. At what approximate distance proximal to the tip of the lateral malleolus does the superficial peroneal nerve pierce the deep fascia to become subcutaneous?

. 1-2 cm
. 5-7 cm
. 10-12 cm
. 15-20 cm
. 25-30 cm

Correct Answer & Explanation

. 1-2 cm

Explanation

The superficial peroneal nerve courses downward within the lateral compartment of the leg and pierces the crural fascia to become superficial/subcutaneous approximately 10 to 12 cm proximal to the tip of the lateral malleolus. It is at significant risk during anterolateral ankle arthroscopy portals and approaches to the distal fibula.

Question 5525

Topic: 8. Foot and Ankle

The artery of the tarsal canal provides the dominant blood supply to the body of the talus. From which main parent vessel does the artery of the tarsal canal directly originate?

. Anterior tibial artery
. Posterior tibial artery
. Peroneal artery
. Dorsalis pedis artery
. Medial plantar artery

Correct Answer & Explanation

. Anterior tibial artery

Explanation

The posterior tibial artery gives rise to the artery of the tarsal canal, which courses through the deltoid ligament to enter the tarsal canal. It forms an anastomotic sling with the artery of the sinus tarsi (which arises from the perforating peroneal and dorsalis pedis arteries) to supply the talar body.

Question 5526

Topic: 8. Foot and Ankle

The Lisfranc ligament is essential for the stability of the midfoot and the tarsometatarsal articulation. It connects which two bony structures?

. Medial cuneiform to the base of the first metatarsal
. Medial cuneiform to the base of the second metatarsal
. Middle cuneiform to the base of the second metatarsal
. Lateral cuneiform to the base of the third metatarsal
. Cuboid to the base of the fourth metatarsal

Correct Answer & Explanation

. Medial cuneiform to the base of the first metatarsal

Explanation

The true Lisfranc ligament runs from the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. It is the largest and strongest of the tarsometatarsal ligaments.

Question 5527

Topic: 8. Foot and Ankle

From anterior/medial to posterior/lateral, what is the correct anatomical order of structures passing behind the medial malleolus in the tarsal tunnel?

. Tibialis posterior tendon, Flexor digitorum longus tendon, Posterior tibial artery, Tibial nerve, Flexor hallucis longus tendon
. Flexor digitorum longus, Tibialis posterior, Tibial nerve, Posterior tibial artery, Flexor hallucis longus
. Tibialis posterior tendon, Flexor hallucis longus, Tibial nerve, Posterior tibial artery, Flexor digitorum longus
. Tibialis posterior tendon, Posterior tibial artery, Tibial nerve, Flexor digitorum longus, Flexor hallucis longus
. Flexor hallucis longus, Tibialis posterior, Posterior tibial artery, Tibial nerve, Flexor digitorum longus

Correct Answer & Explanation

. Tibialis posterior tendon, Flexor digitorum longus tendon, Posterior tibial artery, Tibial nerve, Flexor hallucis longus tendon

Explanation

The correct sequence from anterior to posterior is Tibialis posterior, flexor Digitorum longus, Artery (posterior tibial), Vein, Nerve (tibial), and flexor Hallucis longus. This follows the classic mnemonic 'Tom, Dick, And Very Nervous Harry'.

Question 5528

Topic: 8. Foot and Ankle
A patient presents with a high-energy knee dislocation (KD III) resulting in an abnormal ankle-brachial index (ABI). Angiography reveals an occlusion of the popliteal artery. The popliteal artery is relatively fixed and highly susceptible to tethering and intimal injury between which two anatomic structures?
. Adductor hiatus and soleal arch
. Inguinal ligament and adductor hiatus
. Soleal arch and interosseous membrane
. Femoral canal and adductor canal
. Popliteus muscle and proximal tibiofibular joint

Correct Answer & Explanation

. Adductor hiatus and soleal arch

Explanation

The popliteal artery is firmly tethered proximally at its exit from Hunter's canal (the adductor hiatus) and distally at the fibrous arch of the soleus. This anatomic fixation prevents mobility during high-energy knee dislocations, increasing the risk of vascular injury.

Question 5529

Topic: 8. Foot and Ankle

While performing a percutaneous or minimally invasive repair of an acute Achilles tendon rupture, the surgeon must be cautious of the sural nerve. At what approximate distance proximal to the calcaneal insertion does the sural nerve typically cross the lateral border of the Achilles tendon?

. 2 cm
. 5 cm
. 10 cm
. 15 cm
. 20 cm

Correct Answer & Explanation

. 2 cm

Explanation

The sural nerve crosses from the midline to the lateral border of the Achilles tendon approximately 10 cm proximal to its insertion on the calcaneus. Dissection or percutaneous suturing proximal to this level carries a higher risk of sural nerve injury.

Question 5530

Topic: 8. Foot and Ankle

The blood supply to the talar body is tenuous, predisposing it to avascular necrosis following displaced talar neck fractures. Which of the following arteries provides the majority of the blood supply to the talar body?

. Artery of the tarsal sinus
. Artery of the tarsal canal
. Dorsalis pedis artery
. Deltoid branch of the posterior tibial artery
. Anterior lateral malleolar artery

Correct Answer & Explanation

. Artery of the tarsal sinus

Explanation

The artery of the tarsal canal is a branch of the posterior tibial artery and provides the dominant blood supply to the talar body. The artery of the tarsal sinus (from the anterior tibial/dorsalis pedis and peroneal arteries) supplies the talar head and neck.

Question 5531

Topic: 8. Foot and Ankle

In the surgical treatment of a midfoot deformity, a surgeon exposes the plantar aspect of the foot and encounters the Master Knot of Henry. Which of the following best describes the anatomical relationship at this specific location?

. The flexor hallucis longus (FHL) crosses dorsal to the flexor digitorum longus (FDL)
. The FHL crosses plantar to the FDL
. The tibialis posterior crosses dorsal to the FDL
. The FDL crosses plantar to the tibialis anterior
. The sural nerve crosses over the FHL

Correct Answer & Explanation

. The flexor hallucis longus (FHL) crosses dorsal to the flexor digitorum longus (FDL)

Explanation

At the Master Knot of Henry, located in the plantar midfoot, the flexor hallucis longus (FHL) tendon crosses deep (dorsal) to the flexor digitorum longus (FDL) tendon. The FDL crosses from medial to lateral over the FHL.

Question 5532

Topic: 8. Foot and Ankle

A 22-year-old collegiate football player sustains an axial load to a plantarflexed foot. Weight-bearing radiographs reveal widening of the interval between the medial and middle cuneiforms, and between the first and second metatarsal bases, with no obvious fractures (purely ligamentous Lisfranc injury). What is the optimal surgical treatment associated with the best functional outcome for this specific injury pattern?

. Closed reduction and percutaneous pinning
. Open reduction and internal fixation (ORIF) with transarticular screws
. Primary arthrodesis of the medial column (first, second, and third tarsometatarsal joints)
. Open reduction and flexible suture-button fixation
. Non-weight-bearing cast for 8 weeks

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

For purely ligamentous Lisfranc injuries, multiple studies (including classic work by Ly and Coetzee) have demonstrated that primary arthrodesis provides superior functional outcomes, a higher rate of return to pre-injury activity level, and fewer secondary surgeries compared to open reduction and internal fixation (ORIF). ORIF in purely ligamentous variants often leads to hardware failure, loss of reduction, and painful post-traumatic osteoarthritis.

Question 5533

Topic: 8. Foot and Ankle

A 35-year-old roofer falls from a height and sustains a displaced intra-articular calcaneus fracture. He undergoes open reduction and internal fixation via an extensile lateral approach. Which of the following arteries provides the primary blood supply to the lateral soft-tissue flap elevated in this approach?

. Dorsalis pedis artery
. Medial plantar artery
. Lateral calcaneal artery
. Sural artery
. Anterior tibial artery

Correct Answer & Explanation

. Dorsalis pedis artery

Explanation

The primary blood supply to the corner of the lateral extensile flap in calcaneus fracture surgery is the lateral calcaneal artery, which is a terminal branch of the peroneal artery. Careful full-thickness, subperiosteal flap elevation and 'no-touch' retractor techniques (using K-wires into the talus and fibula) are critical to preserve this vascular supply and prevent ischemic wound necrosis.

Question 5534

Topic: 8. Foot and Ankle

The Lisfranc ligament is a crucial stabilizing structure of the midfoot. Between which two osseous structures does the true Lisfranc ligament travel?

. Base of the 1st metatarsal and base of the 2nd metatarsal
. Lateral aspect of the medial cuneiform and medial aspect of the base of the 2nd metatarsal
. Medial aspect of the lateral cuneiform and medial aspect of the base of the 2nd metatarsal
. Plantar aspect of the medial cuneiform and plantar aspect of the 1st metatarsal
. Cuboid and base of the 4th metatarsal

Correct Answer & Explanation

. Base of the 1st metatarsal and base of the 2nd metatarsal

Explanation

The Lisfranc ligament is the strongest ligament in the midfoot. It originates on the lateral aspect of the medial cuneiform and inserts onto the medial aspect of the base of the second metatarsal. Notably, there is no direct ligamentous connection between the bases of the first and second metatarsals.

Question 5535

Topic: 8. Foot and Ankle

A 28-year-old male sustains a traumatic knee dislocation during a football game. Upon arrival at the ED, the knee is reduced. His pedal pulses are palpable, but his Ankle-Brachial Index (ABI) is measured at 0.82. What is the most appropriate next step in management?

. Discharge with a hinged knee brace and early outpatient orthopedic follow-up
. Immediate surgical exploration of the popliteal artery
. CT angiography of the lower extremity
. Serial ABI measurements every 4 hours for 24 hours
. Application of a long-leg cast

Correct Answer & Explanation

. Discharge with a hinged knee brace and early outpatient orthopedic follow-up

Explanation

In the setting of a knee dislocation, an ABI of less than 0.90 is an absolute indication for advanced vascular imaging (CT angiogram) or formal arterial duplex evaluation. While the presence of hard signs of vascular injury (expanding hematoma, absent pulses, ischemia) demands immediate surgical exploration, an asymmetric ABI (<0.90) with palpable pulses requires an angiogram to rule out an intimal flap or occult injury.

Question 5536

Topic: 8. Foot and Ankle

A 38-year-old roofer falls from a height and sustains a severely displaced intra-articular calcaneus fracture. The surgeon opts for open reduction and internal fixation utilizing an extensile lateral approach. The full-thickness fasciocutaneous flap elevated in this approach receives its primary blood supply from which of the following vessels?

. Lateral tarsal artery
. Sural artery
. Lateral calcaneal artery
. Peroneal artery
. Anterior tibial artery

Correct Answer & Explanation

. Lateral tarsal artery

Explanation

The primary blood supply to the lateral fasciocutaneous flap in an extensile lateral approach to the calcaneus is the lateral calcaneal artery, a terminal branch of the peroneal artery. To preserve this crucial blood supply and prevent flap necrosis, the flap must be elevated in a full-thickness, subperiosteal 'no-touch' fashion.

Question 5537

Topic: 8. Foot and Ankle

A 25-year-old female presents to the trauma bay after a high-speed skiing accident.

Examination reveals a clinically obvious posterior knee dislocation. The joint is urgently reduced in the emergency department. Post-reduction, the extremity is warm, but pulses are slightly asymmetric. An Ankle-Brachial Index (ABI) is calculated to be 0.85. What is the most appropriate next step in management?

. Observation with serial neurovascular exams every 4 hours
. Immediate surgical exploration of the popliteal artery
. CT angiography of the lower extremity
. Discharge with a hinged knee brace and outpatient follow-up
. Duplex ultrasound in 24 hours

Correct Answer & Explanation

. Observation with serial neurovascular exams every 4 hours

Explanation

Knee dislocations carry a high risk of popliteal artery injury. Following reduction, an ABI should be measured. An ABI > 0.9 with symmetrical pulses can typically be observed. However, an ABI < 0.9 indicates impaired distal perfusion and mandates advanced vascular imaging, most commonly a CT angiogram, to rule out an intimal flap or flow-limiting popliteal artery injury.

Question 5538

Topic: 8. Foot and Ankle

A 29-year-old football player sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs reveal a 3 mm diastasis between the base of the first and second metatarsals. The primary ligamentous stabilizer disrupted in this injury (the Lisfranc ligament) courses between which two osseous structures?

. Medial cuneiform and base of the first metatarsal
. Medial cuneiform and base of the second metatarsal
. Middle cuneiform and base of the second metatarsal
. Lateral cuneiform and base of the third metatarsal
. Navicular and base of the first metatarsal

Correct Answer & Explanation

. Medial cuneiform and base of the first metatarsal

Explanation

The Lisfranc ligament is the strongest restraint to lateral displacement of the second metatarsal. It originates on the lateral aspect of the medial cuneiform and inserts onto the medial aspect of the base of the second metatarsal. There is no ligamentous connection between the bases of the first and second metatarsals, making the Lisfranc ligament vital for midfoot stability.

Question 5539

Topic: 8. Foot and Ankle

During open reduction and internal fixation of a Weber C ankle fracture, the surgeon performs a Cotton test to assess the integrity of the syndesmosis. Which of the following intraoperative radiographic findings during the test indicates dynamic syndesmotic instability requiring fixation?

. Tibiofibular clear space greater than 5 mm on the AP view
. Tibiofibular overlap greater than 10 mm on the mortise view
. Medial clear space greater than 4 mm on the mortise view with lateral pull
. Talar tilt greater than 5 degrees on the stress view
. Decreased talocrural angle

Correct Answer & Explanation

. Tibiofibular clear space greater than 5 mm on the AP view

Explanation

The Cotton test involves placing a bone hook around the fibula and pulling laterally to stress the syndesmosis. Dynamic widening of the medial clear space (typically > 4-5 mm) or the tibiofibular clear space on the mortise view indicates syndesmotic instability. If the medial clear space opens, it indicates that the deltoid ligament is incompetent and the talus is shifting laterally with the fibula, warranting syndesmotic fixation.

Question 5540

Topic: Midfoot & Hindfoot
A 28-year-old male sustains a talar neck fracture following a fall from a height. Radiographs demonstrate a displaced fracture of the talar neck with subluxation of the subtalar joint, but the tibiotalar joint remains congruous. According to the Hawkins classification, what is the fracture type and the historically associated risk of avascular necrosis (AVN) of the talar body?
. Hawkins Type I, less than 10% risk of AVN
. Hawkins Type II, 20% to 50% risk of AVN
. Hawkins Type III, almost 100% risk of AVN
. Hawkins Type IV, 10% to 20% risk of AVN
. Hawkins Type II, greater than 90% risk of AVN

Correct Answer & Explanation

. Hawkins Type II, 20% to 50% risk of AVN

Explanation

This injury is a Hawkins Type II talar neck fracture, defined by displacement of the talar neck with subluxation or dislocation of the subtalar joint, while the ankle (tibiotalar) joint remains intact. The risk of avascular necrosis (AVN) for Hawkins Type II fractures is widely cited as 20% to 50%. Type I (nondisplaced) is <10%, Type III (subtalar and tibiotalar dislocation) is >90%, and Type IV (Type III plus talonavicular disruption) approaches 100%.

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