ABOS Part I Comprehensive Review - Batch 50

Question 1

A 32-year-old male presents with chronic right knee pain and a progressive varus deformity. Standing long-leg radiographs reveal a Mechanical Axis Deviation (MAD) of 25mm medial to the center of the knee. Further analysis shows a Mechanical Lateral D

Accepted Answer

The deformity is entirely tibial, localized to the proximal tibia.

Question 2

A 55-year-old patient presents with a severe tibial varus deformity, as shown in the preoperative planning radiograph below. The surgeon has meticulously drawn the mechanical axes of the proximal and distal tibial segments, identifying their intersec

Accepted Answer

It is the Center of Rotation of Angulation (CORA), dictating the ideal osteotomy and hinge placement.

Question 3

A 40-year-old patient requires correction of a distal femoral valgus deformity. Preoperative planning reveals the CORA is located precisely at the articular surface of the lateral femoral condyle. To achieve perfect mechanical axis restoration while

Accepted Answer

Restoration of the mechanical axis with an obligatory translation at the osteotomy site.

Question 4

A 28-year-old patient with a large, multiplanar angular deformity of the tibia requires correction while preserving limb length and maximizing bony contact for rapid healing. The surgeon opts for a focal dome osteotomy, as depicted in the intraoperat

Accepted Answer

It creates broad cortical-to-cortical contact, promoting rapid primary bone healing without graft.

Question 5

A 60-year-old patient with severe bilateral genu varum is undergoing surgical correction. The surgeon plans to use Fixator Assisted Nailing (FAN) for the tibial deformities. Which of the following statements best describes the primary advantage of th

Accepted Answer

FAN combines the precision of temporary external fixation with the biological advantages of intramedullary nailing, allowing for immediate frame removal.

Question 6

During a Fixator Assisted Nailing (FAN) procedure for a proximal tibial varus deformity, the surgeon is preparing to place the half-pins for the monolateral external fixator. To ensure an unimpeded path for the intramedullary reamers and the definiti

Accepted Answer

Two half-pins posteriorly in the proximal fragment and two posteriorly in the distal fragment.

Question 7

A 48-year-old patient presents with a significant genu varum deformity and a concomitant 1.5 cm leg length discrepancy (LLD) in the affected limb. The deformity is localized to the proximal tibia. The surgeon's primary goal is to correct the varus an

Accepted Answer

An opening wedge osteotomy of the proximal tibia.

Question 8

Following a Fixator Assisted Nailing (FAN) procedure for a proximal tibial varus deformity, the external fixator is removed, and the intramedullary nail is locked. The surgeon then considers the need for interference (Poller) screws. The close-up flu

Accepted Answer

To block the nail from drifting medially, thereby preventing recurrence of the varus deformity.

Question 9

A 35-year-old patient undergoes Fixator Assisted Nailing (FAN) for a valgus deformity of the distal femur. The deformity has been acutely corrected, and the intramedullary nail is in place. To prevent the 'bell-clapper effect' and maintain the correc

Accepted Answer

On the lateral side of the nail, in the acute angle of the deformity.

Question 10

The multi-panel image below illustrates the journey of a patient undergoing Fixator Assisted Nailing (FAN) for bilateral bowleg deformities. Panel (g) shows the postoperative clinical appearance, and panel (e) shows the postoperative standing long-le

Accepted Answer

The precise restoration of the mechanical axis and dramatic cosmetic and functional improvement achieved by acute correction.

ABOS Part I Orthopaedic Deformity Correction, Limb Reconstruction & Gait Analysis Review | Part 21914

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Key Takeaway