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Ankle Trauma & Sports MCQs

Practice Set 3 of 9

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

Question 41

Topic: Ankle Trauma & Sports

During open reduction and internal fixation of a distal tibia pilon fracture, a large anterolateral articular fragment (the Chaput fragment) is identified. Which of the following ligamentous structures remains attached to this specific fragment?

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The anterolateral distal tibial articular fragment in a pilon or complex ankle fracture is known as the Chaput fragment (or Tillaux-Chaput). It serves as the tibial attachment site for the Anterior Inferior Tibiofibular Ligament (AITFL). The fibular attachment of the AITFL is the Wagstaffe-Le Fort fragment. The posterior tibial fragment (Volkmann's triangle) is the attachment for the Posterior Inferior Tibiofibular Ligament (PITFL).

Question 42

Topic: Ankle Trauma & Sports
In the Lauge-Hansen classification system, a pronation-abduction ankle fracture has what characteristic fibular fracture pattern?
. Transverse fracture at or below the level of the syndesmosis
. Short oblique fracture running from anteroinferior to posteriosuperior
. Short oblique fracture running from posteroinferior to anteriosuperior
. Comminuted fracture above the level of the syndesmosis
. Wagstaff fracture

Correct Answer & Explanation

. Comminuted fracture above the level of the syndesmosis

Explanation

Discussion: In the Lauge-Hansen classification, the characteristic fibular fracture pattern in a pronation-abduction injury is a comminuted fibular fracture above the level of the syndesmosis. In the first stage of this injury pattern, the deltoid fails in tension, or an avulsion fracture of the medial malleolus occurs. In the second stage, the anterior inferior tibiofibular ligament ruptures, or a small bony avulsion of this ligament's insertion/origin occurs. The final stage includes the creation of a comminuted fibular fracture above the level of the syndesmosis.

Question 43

Topic: Ankle Trauma & Sports

-A 30-year-old man sustained the injury seen in Figure 261. According to the Lauge-Hansen Classification System, the fracture should be classified as

. pronation-abduction.
. pronation-adduction.
. pronation-external rotation.
. supination-adduction.
. supination-external rotation.

Correct Answer & Explanation

. pronation-abduction.

Explanation

Question 44

Topic: Ankle Trauma & Sports
A 22-year-old female presents with an ankle injury after a fall during a soccer match. Radiographs demonstrate a short oblique fracture of the lateral malleolus starting at the level of the syndesmosis and extending proximally and posteriorly. Additionally, the medial clear space is widened to 6 mm on the gravity stress view. According to the Lauge-Hansen classification, what stage of injury does this represent?
. Supination-External Rotation Stage II
. Pronation-External Rotation Stage III
. Supination-External Rotation Stage IV
. Pronation-Abduction Stage III
. Supination-Adduction Stage II

Correct Answer & Explanation

. Supination-External Rotation Stage IV

Explanation

The fracture pattern described is a Supination-External Rotation (SER) injury. The sequence of injury in SER is: Stage I (AITFL rupture), Stage II (short oblique/spiral fracture of the distal fibula), Stage III (PITFL rupture or posterior malleolus fracture), and Stage IV (deltoid ligament rupture or medial malleolus transverse fracture). Widening of the medial clear space indicates a disrupted deltoid ligament, moving this to an SER Stage IV injury.

Question 45

Topic: Ankle Trauma & Sports
A 28-year-old male presents with isolated medial ankle pain and swelling after an inversion and rotational injury. Radiographs show a transverse fracture of the medial malleolus and widening of the tibiofibular clear space. A full-length tibia-fibula radiograph reveals a fracture of the proximal third of the fibula. What is the most likely Lauge-Hansen mechanism for this specific injury pattern (Maisonneuve fracture)?
. Pronation-External Rotation
. Supination-External Rotation
. Pronation-Abduction
. Supination-Adduction
. Pronation-Dorsiflexion

Correct Answer & Explanation

. Pronation-External Rotation

Explanation

A Maisonneuve fracture is classically described as a Pronation-External Rotation (PER) stage III or IV injury. The medial injury (deltoid rupture or medial malleolar fracture) occurs first (Stage I), followed by rupture of the anterior tibiofibular ligament and interosseous membrane (Stage II), and then the fibula fractures at the proximal third as the force exits (Stage III).

Question 46

Topic: Ankle Trauma & Sports
A 14-year-old boy falls while skateboarding and sustains a Salter-Harris III fracture of the anterolateral aspect of the distal tibia. Which specific ligament is responsible for the avulsion force creating this fracture fragment?
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Deep deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The Tillaux fracture is an avulsion of the anterolateral epiphysis of the distal tibia. It occurs in adolescents due to the asymmetrical closure of the distal tibial physis (which closes central, then medial, then lateral). An external rotation force places tension on the anterior inferior tibiofibular ligament (AITFL), which avulses the still-open anterolateral epiphysis.

Question 47

Topic: Ankle Trauma & Sports
A 14-year-old boy presents with an ankle injury after a skateboarding accident. Radiographs reveal a Salter-Harris type III fracture of the anterolateral aspect of the distal tibia epiphysis. Which of the following ligaments is responsible for this avulsion injury?
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Calcaneofibular ligament (CFL)
. Anterior talofibular ligament (ATFL)
. Deep deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis caused by tension from the anterior inferior tibiofibular ligament (AITFL). It occurs in adolescents because the lateral physis is the last to close.

Question 48

Topic: Ankle Trauma & Sports
A 14-year-old boy sustains an ankle injury while playing soccer. Radiographs reveal a Salter-Harris III fracture of the anterolateral distal tibia. Which ligament's avulsion force is fundamentally responsible for this specific fracture pattern?
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The patient has a Tillaux fracture, which is an avulsion fracture of the anterolateral aspect of the distal tibial epiphysis. It occurs during adolescence due to an external rotation force pulling on the anterior inferior tibiofibular ligament (AITFL). This happens because the distal tibial physis closes in a specific pattern: central, then medial, and finally lateral. The lateral physis is the last to close, making it vulnerable to avulsion by the AITFL.

Question 49

Topic: Ankle Trauma & Sports

Following open reduction and internal fixation of a Weber C fibula fracture, the surgeon intraoperatively evaluates the integrity of the distal tibiofibular syndesmosis. Which of the following radiographic parameters on a standard non-rotated AP and mortise radiograph is considered the most reliable indicator of a well-reduced syndesmosis?

. Tibiofibular clear space of < 6 mm measured 1 cm proximal to the plafond on both AP and mortise views
. Tibiofibular overlap of > 1 mm measured on the AP view only
. Medial clear space > 4 mm measured on the mortise view
. Talar tilt angle < 5 degrees
. Absolute linear alignment of the distal fibula with the anterior tibial tubercle

Correct Answer & Explanation

. Tibiofibular clear space of < 6 mm measured 1 cm proximal to the plafond on both AP and mortise views

Explanation

The tibiofibular clear space, measured 1 cm proximal to the tibial plafond, should normally be < 6 mm on both AP and mortise radiographs. It is widely considered the most reliable plain radiographic parameter for evaluating syndesmotic integrity because, unlike the tibiofibular overlap (which is highly sensitive to the degree of leg rotation), the clear space remains relatively constant regardless of minor variations in rotation.

Question 50

Topic: Ankle Trauma & Sports

A 50-year-old male sustains a severe pilon fracture. The preoperative CT scan demonstrates a large, displaced anterolateral distal tibial articular fragment (the Tillaux-Chaput fragment). Which of the following ligaments remains attached to this fragment and often dictates its displacement?

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The Tillaux-Chaput fragment is the anterolateral articular fragment of the distal tibia seen in pilon or transitional ankle fractures. It serves as the primary tibial attachment site for the Anterior Inferior Tibiofibular Ligament (AITFL). Its corresponding fibular avulsion counterpart is the Wagstaffe-Le Fort fragment.

Question 51

Topic: Ankle Trauma & Sports

A 45-year-old man sustains a closed ankle fracture. Radiographs demonstrate a transverse medial malleolus fracture, a high proximal fibular fracture (Maisonneuve), and widening of the tibiofibular syndesmosis. According to the Lauge-Hansen classification, what is the mechanism of injury?

. Supination-Adduction
. Supination-External Rotation
. Pronation-Abduction
. Pronation-External Rotation
. Axial Loading

Correct Answer & Explanation

. Pronation-External Rotation

Explanation

A transverse medial malleolar fracture (or deltoid rupture) followed by a high fibula fracture characterizes a Pronation-External Rotation (PER) injury. The initial pronation applies tension to medial structures, while external rotation tears the syndesmosis and fractures the proximal fibula.

Question 52

Topic: Ankle Trauma & Sports
A 25-year-old gymnast undergoes a modified Broström-Gould procedure for chronic lateral ankle instability after failing extensive physical therapy. Which anatomical structure is advanced and sutured to the fibula to augment the primary repair in the 'Gould' modification?
. Peroneus brevis tendon
. Peroneus tertius tendon
. Inferior extensor retinaculum
. Superior peroneal retinaculum
. Plantaris tendon

Correct Answer & Explanation

. Inferior extensor retinaculum

Explanation

The standard Broström procedure involves direct anatomic repair of the ATFL and CFL. The Gould modification augments this repair by mobilizing the inferior extensor retinaculum and anchoring it to the distal fibula to reinforce the lateral complex.

Question 53

Topic: Ankle Trauma & Sports

A 28-year-old rugby player undergoes ORIF of a pronation-external rotation (PER) ankle fracture. Intraoperatively, the syndesmosis remains unstable after fibular fixation and requires screw fixation. Which of the following variables is the most significant predictor of poor long-term functional outcome?

. Using two syndesmotic screws instead of one
. Malreduction of the syndesmosis prior to fixation
. Retaining the screw beyond 12 weeks postoperatively
. Screw breakage within the syndesmosis prior to removal
. Using 3.5mm instead of 4.5mm screws

Correct Answer & Explanation

. Malreduction of the syndesmosis prior to fixation

Explanation

Accurate anatomical reduction of the distal tibiofibular syndesmosis is the single most critical factor determining long-term functional outcomes in syndesmotic injuries. Malreduction alters tibiotalar contact stresses, leading to early onset of post-traumatic osteoarthritis.

Question 54

Topic: Ankle Trauma & Sports

In the management of an unstable ankle fracture, the posterior malleolus is often evaluated for fixation. Biomechanical studies have shown that direct osteosynthesis of the posterior malleolus provides greater syndesmotic stability than isolated trans-syndesmotic screws because it directly restores the tension of which ligament?

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Calcaneofibular ligament (CFL)
. Deltoid ligament
. Interosseous ligament

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

The posterior inferior tibiofibular ligament (PITFL) attaches to the posterior malleolus. The PITFL provides approximately 40-50% of the stability of the syndesmosis. Anatomically reducing and fixing a posterior malleolus fracture directly restores the PITFL's stabilizing function, providing superior biomechanical strength to the syndesmosis compared to trans-syndesmotic screw fixation alone.

Question 55

Topic: Ankle Trauma & Sports

A 28-year-old skier falls forward with her ankles flexed, experiencing a sudden snapping sensation and acute pain posterior to the lateral malleolus. Radiographs demonstrate a small avulsion fracture ('fleck sign') off the posterolateral margin of the distal fibula. This radiographic finding is pathognomonic for an injury to which of the following structures?

. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Inferior extensor retinaculum
. Superior peroneal retinaculum (SPR)

Correct Answer & Explanation

. Superior peroneal retinaculum (SPR)

Explanation

A 'fleck sign' or rim fracture off the posterolateral border of the distal fibula represents an avulsion of the superior peroneal retinaculum (SPR). This injury leads to peroneal tendon subluxation or dislocation. It classically occurs during forceful dorsiflexion and reflex contraction of the peroneal muscles.

Question 56

Topic: Ankle Trauma & Sports

A 14-year-old male sustains an ankle injury resulting in a juvenile Tillaux fracture. Which of the following ligaments is responsible for the avulsion of the anterolateral distal tibial epiphysis?

. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis. It occurs in adolescents because the distal tibial physis closes from medial to lateral. The open anterolateral physis remains vulnerable to avulsion by the anterior inferior tibiofibular ligament (AITFL) during an external rotation injury.

Question 57

Topic: Ankle Trauma & Sports

A 35-year-old patient sustained a bimalleolar ankle fracture. What is the most reliable method of predicting a tear of the interosseous membrane?

Trauma Board Review 2006: High-Yield MCQs (Set 2) - Figure 29

. Level of the fibular fracture
. Lauge-Hansen fracture class
. Intraoperative stress testing
. Widening of the medial clear space
. Talar dislocation

Correct Answer & Explanation

. Intraoperative stress testing

Explanation

The Weber and Lauge-Hansen fracture classifications suggest that the interosseous membrane (IOM) is torn with certain fracture patterns. In a recent study that evaluated ankle fractures with MRI, Nielson and associates identified 30 patients with IOM tears. Ten of the tears did not correspond with the level of the fibular fracture. The authors concluded that stability of the syndesmosis should not be based on the level of the fibular fracture alone but should also include an intraoperative stress test. Transsyndesmotic fixation should be considered for those fractures where the intraoperative stress test demonstrates instability. A widened medial clear space may occur with a deltoid injury and distal fibular fracture in the absence of a significant tear of the interosseous membrane.

Question 58

Topic: Ankle Trauma & Sports

A 34-year-old man suffers an ankle injury after slipping on ice. Radiographs reveal a transverse fracture of the medial malleolus and a short oblique fracture of the lateral malleolus starting at the level of the joint line. According to the Lauge-Hansen classification, what is the most likely mechanism of injury?

. Supination-Adduction (SAD)
. Supination-External Rotation (SER)
. Pronation-Abduction (PAB)
. Pronation-External Rotation (PER)
. Axial loading

Correct Answer & Explanation

. Supination-External Rotation (SER)

Explanation

The Lauge-Hansen Supination-External Rotation (SER) injury is the most common type of ankle fracture. The sequence of injury is: 1) Anterior inferior tibiofibular ligament (AITFL) rupture, 2) Short oblique/spiral fracture of the fibula at the level of the syndesmosis, 3) Posterior inferior tibiofibular ligament (PITFL) rupture or posterior malleolus fracture, 4) Medial malleolus transverse fracture or deltoid ligament rupture. The short oblique fibula fracture at the joint line is characteristic of SER injuries.

Question 59

Topic: Ankle Trauma & Sports

The strongest and most important ligamentous stabilizer of the distal tibiofibular syndesmosis is the:

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Interosseous ligament
. Deltoid ligament
. Transverse tibiofibular ligament

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

While the anterior inferior tibiofibular ligament (AITFL) is typically the first to tear in a syndesmotic injury, biomechanical studies demonstrate that the posterior inferior tibiofibular ligament (PITFL) provides the greatest proportion of strength (approximately 42%) to the syndesmosis, making it the strongest stabilizer.

Question 60

Topic: Ankle Trauma & Sports

A 45-year-old male with a history of recurrent ankle sprains develops chronic lateral ankle instability. Clinical examination reveals a positive anterior drawer test and talar tilt test. Imaging shows chronic attenuation of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL). He fails a trial of bracing and physical therapy. What is the MOST appropriate surgical procedure for definitive stabilization?

. Arthroscopic debridement of impingement.
. Lateral ankle arthrodesis.
. Modified Brostrom-Gould procedure.
. Peroneal tendon transfer.
. Ankle replacement.

Correct Answer & Explanation

. Modified Brostrom-Gould procedure.

Explanation

For chronic lateral ankle instability due to attenuation of the ATFL and CFL that has failed conservative management, the Modified Brostrom-Gould procedure is considered the 'gold standard' and most appropriate surgical intervention. This procedure involves direct repair of the attenuated ATFL and CFL by shortening and reattaching them, often reinforced with the inferior extensor retinaculum (Gould modification). Arthroscopic debridement is for impingement, not instability. Lateral ankle arthrodesis is a salvage procedure for end-stage arthritis. Peroneal tendon transfer is a reconstructive procedure usually reserved for failed Brostroms, highly ligamentous lax patients, or poor tissue quality. Ankle replacement is for end-stage arthritis.

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