ABOS Part I Comprehensive Review - Batch 31

Question 1

A 35-year-old male presents with chronic ankle pain and a suspected distal tibial deformity. A weight-bearing coronal radiograph is obtained, and the following measurement is performed:Based on the image provided and Paley's principles, what is the n

Accepted Answer

86-92°; Frontal (coronal) plane malalignment of the ankle joint.

Question 2

A 50-year-old female with a history of recurrent ankle sprains and anterior impingement symptoms undergoes radiographic evaluation. A lateral radiograph is obtained, and the following measurement is performed:The image displays the measurement of the

Accepted Answer

80°; Distal tibial recurvatum.

Question 3

A 60-year-old patient is being evaluated for a complex tibial deformity following a malunited fracture. The surgeon is planning a corrective osteotomy and reviews the following diagram:The diagram illustrates the Center of Rotation of Angulation (COR

Accepted Answer

It is the geometric apex where the proximal and distal mechanical axes of a deformed bone intersect, serving as the critical first step for surgical planning.

Question 4

A surgeon is planning a distal tibial osteotomy for a patient with a varus ankle deformity. After meticulous radiographic analysis, the CORA is identified 5 cm proximal to the ankle joint line. The surgeon decides to perform the osteotomy precisely a

Accepted Answer

The correction will achieve pure angular realignment without inducing any secondary translation.

Question 5

A patient presents with a distal tibial valgus deformity. The CORA is located 8 cm proximal to the ankle joint. Due to concerns about soft tissue envelope and neurovascular structures, the surgeon decides to perform the osteotomy 3 cm proximal to the

Accepted Answer

The correction will require both angulation and a planned translation to achieve proper alignment.

Question 6

A surgeon is correcting a complex mid-diaphyseal tibial deformity. The CORA is identified, but due to technical constraints, the osteotomy is performed 4 cm distal to the CORA, and the external fixator hinge is inadvertently placed 2 cm proximal to t

Accepted Answer

An undesirable secondary translation deformity will be induced, complicating the correction.

Question 7

A resident is reviewing a long-leg alignment film for a patient with ankle osteoarthritis and a suspected lower extremity malalignment. The attending asks about the difference between the overall mechanical axis and the tibial mechanical axis.Which o

Accepted Answer

The tibial mechanical axis connects the center of the tibial plateau to the center of the tibial plafond, whereas the overall mechanical axis connects the center of the femoral head to the center of the ankle mortise.

Question 8

A 40-year-old patient presents with progressive medial ankle pain and early signs of medial ankle osteoarthritis. Radiographic analysis reveals a Lateral Distal Tibial Angle (LDTA) of 82°.Based on this finding and Paley's principles, what is the most

Accepted Answer

Distal tibial varus, leading to increased medial ankle joint pressure.

Question 9

A patient presents with severe ankle pain and deformity. During the initial assessment, the orthopedic surgeon emphasizes the need for full-length standing radiographs and a comprehensive examination of the knee and hip, in addition to the ankle and

Accepted Answer

To understand how compensatory mechanisms in the knee, hip, and spine influence and are influenced by ankle and foot alignment.

Question 10

A 55-year-old patient with a history of a distal tibia fracture presents with chronic ankle pain and a noticeable limb length discrepancy. Full-length standing radiographs show a Mechanical Axis Deviation (MAD) of +20mm (medial to the center of the k

Accepted Answer

The patient has a distal tibial varus and a recurvatum deformity, contributing to medial ankle overload and anterior impingement.

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Key Takeaway