Practice Set 68 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.
In deformity planning, the Center of Rotation of Angulation (CORA) is determined by the intersection of which two lines?
. The mechanical axis of the proximal segment and the mechanical axis of the distal segment
When performing a supramalleolar osteotomy of the tibia to correct a severe ankle varus deformity, what is the typical management of the fibula?
. A concurrent fibular osteotomy is required to allow angular correction.
A patient with long-standing post-traumatic distal tibia varus presents with ankle pain. Weight-bearing radiographs show an asymmetric narrowing of the medial tibiotalar joint space. The angle formed between the tibial plafond and the talar dome is measured. What does an abnormally widened Joint Line Convergence Angle (JLCA) in this setting typically indicate?
. Ligamentous laxity or intra-articular cartilage wear
A patient has a severe equinus contracture of the ankle joint. Over time, what compensatory skeletal deformity might develop in the distal tibia to keep the foot plantigrade?
. Recurvatum deformity
When choosing the level of an osteotomy to correct a distal tibial deformity, the surgeon opts to make the cut in the metaphyseal bone rather than the diaphyseal bone, despite the CORA being in the diaphysis. What is the primary biological advantage of this decision?
. Metaphyseal bone has a larger cross-sectional area and superior blood supply, promoting faster healing.
A 40-year-old male presents with post-traumatic ankle deformity. Radiographic evaluation of the lower extremity is performed to plan a supramalleolar osteotomy. According to Paley's principles of deformity correction, what is the normal value for the mechanical lateral distal tibial angle (mLDTA)?
. 89 degrees
A 35-year-old patient develops an apex anterior (procurvatum) deformity of the distal tibia following a malunited distal third fracture. How will this sagittal plane deformity affect the Anterior Distal Tibial Angle (ADTA) and ankle biomechanics?
. Decreased ADTA with restricted ankle dorsiflexion
A 55-year-old female with stage 2 Takakura varus ankle osteoarthritis undergoes a medial opening-wedge supramalleolar osteotomy. What is the expected biomechanical effect of this precise surgical intervention?
. Lateralizes the mechanical axis and lengthens the limb
. Fibular shortening or sliding osteotomy
A 28-year-old patient presents with an untreated 15-degree distal tibial varus deformity secondary to a childhood growth plate injury. To maintain a functional, plantigrade foot during weight-bearing, what compensatory deformity most predictably develops?
. Subtalar valgus
A 30-year-old female undergoes a supramalleolar osteotomy for a post-traumatic varus ankle deformity (apex lateral). To execute a medial opening wedge osteotomy, where must the hinge axis logically be positioned relative to the tibia to achieve proper correction?
. Lateral cortex
When evaluating a patient with a post-traumatic valgus deformity of the distal tibia, the surgeon notes an associated clinically significant fibular shortening. Which radiographic parameter is most reliable for identifying the correct length of the fibula relative to the tibia at the ankle?
. Talocrural angle
In the context of ankle deformity correction, what compensatory mechanism commonly occurs in the hindfoot to dynamically accommodate a gradually developing distal tibial varus deformity?
. Subtalar valgus
A patient with a chronic distal tibia varus malunion complains of severe ankle pain. Radiographs reveal an mLDTA of 105 degrees. What is the primary biomechanical consequence of this untreated malunion on the ankle joint?
. Shift of the mechanical axis medially leading to medial compartment overload.
During a supramalleolar osteotomy for a complex valgus ankle deformity, the surgeon places the hinge axis outside the transverse bisector line of the CORA and performs the osteotomy away from the CORA. What is the primary biomechanical consequence of this execution (Paley's Rule 3)?
. Failure to realign the mechanical axes resulting in a secondary translation deformity
A 55-year-old female presents with a longstanding, severe varus diaphyseal tibial malunion. Weight-bearing alignment radiographs reveal a compensatory deformity in the hindfoot. Which of the following compensatory mechanisms at the subtalar joint is most likely present to maintain a plantigrade foot?
. Fixed subtalar valgus (eversion)
A surgeon is performing a closing wedge supramalleolar osteotomy to correct a 20-degree valgus deformity of the ankle. Which of the following is the most appropriate management of the fibula to ensure unrestricted correction and prevent syndesmotic complications?
. A fibular osteotomy should be performed to prevent lateral strutting and tethering
What is the normal Lateral Distal Tibial Angle (LDTA) on a standing AP radiograph of the ankle?
. 86 to 92 degrees
When performing a proximal tibial osteotomy for gradual deformity correction with a circular frame, a fibular osteotomy is required. At which level is the fibula typically osteotomized to minimize the risk of common peroneal nerve injury?
. Middle to distal third junction of the fibula
During tibial lengthening, a patient develops a progressive equinus contracture. Despite aggressive physical therapy, it worsens, threatening the outcome. What is the most appropriate prophylactic or early interventional measure to manage this specific complication?
. Incorporation of the foot into the frame or prophylactic Achilles tendon lengthening