ABOS Part I Comprehensive Review - Batch 70

Question 1

A 32-year-old male presents with progressive right knee pain and a clinical varus deformity. To accurately assess his frontal plane alignment for potential corrective osteotomy, which of the following radiographic techniques is most critical accordin

Accepted Answer

Standing, weight-bearing long-leg AP radiograph with the patella facing strictly forward.

Question 2

A 60-year-old female presents with severe medial compartment osteoarthritis of the left knee. A standing, weight-bearing long-leg AP radiograph reveals a mechanical axis that passes 15 mm medial to the exact center of the knee joint. Based on Paley's

Accepted Answer

A pathological varus deformity, overloading the medial compartment.

Question 3

A 40-year-old male presents with a progressive genu valgum deformity. A long-leg AP radiograph shows a Mechanical Axis Deviation (MAD) passing 10 mm lateral to the center of the knee. Further analysis using the Malorientation Test (MOT) reveals an MP

Accepted Answer

Distal femur

Question 4

A 55-year-old patient with a long-standing varus deformity of the knee is being planned for a high tibial osteotomy. Preoperative radiographs show a Mechanical Axis Deviation (MAD) of 12 mm medial to the knee center. The Medial Proximal Tibial Angle

Accepted Answer

The bony correction should be increased (over-corrected) to compensate for the intra-articular laxity/bone loss.

Question 5

A surgeon is planning a corrective osteotomy for a femoral deformity. The image below illustrates the relationship between the anatomic and mechanical axes of the femur.Based on this diagram and Paley's principles, which statement accurately describe

Accepted Answer

For a proximal femoral deformity (e.g., subtrochanteric), the mechanical and anatomic CORAs will be far apart.

Question 6

A 12-year-old patient with a history of rickets presents with a complex femoral deformity. A long-leg radiograph is obtained and the surgeon performs anatomic axis planning, identifying the axis lines as shown inDiagram 'd'of the image below.Based on

Accepted Answer

Multiple osteotomies, with one at each identified CORA (CORA1 and CORA2).

Question 7

During preoperative planning for a distal femoral varus deformity, the surgeon identifies the intersection of the proximal and distal mechanical axes, defining the CORA. A transverse line is then drawn that perfectly bisects the angle of deformity at

Accepted Answer

It dictates the true level of the deformity, allowing for surgical flexibility in osteotomy placement.

Question 8

A 48-year-old patient has a proximal tibial varus deformity with a CORA located in the highly vascularized proximal tibial metaphysis, an ideal location for an osteotomy. The surgeon plans to perform a high tibial osteotomy. To achieve the most biome

Accepted Answer

Osteotomy Rule One: Osteotomy and hinge placed exactly at the CORA.

Question 9

A 35-year-old patient requires correction of a distal femoral valgus deformity. The CORA is located in the distal femoral diaphysis, an area with poor healing potential and dense bone. To optimize healing and surgical access, the surgeon decides to p

Accepted Answer

Rule Two; angulation combined with necessary translation.

Question 10

A surgeon is performing a valgus-producing (varus-correcting) proximal tibial osteotomy on a patient with significant genu varum. As the correction is achieved, the surgeon is particularly mindful of a specific neurovascular structure that is at risk

Accepted Answer

Peroneal nerve; prophylactic decompression at the fibular neck.

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

ABOS Part I Orthopaedic Surgery & OITE Exam Review: Paley Deformity Correction & Osteotomy Principles | Part 22023

Key Takeaway