ABOS Part I Comprehensive Review - Batch 38

Question 1

A 62-year-old male presents with progressive right knee pain and a noticeable varus thrust during gait. A full-length weight-bearing radiograph is obtained, as shown below. Based on the principles outlined in the Paley Method, which of the following

Accepted Answer

Mechanical Axis Deviation (MAD)

Question 2

A 55-year-old patient with a long-standing varus deformity and a history of lateral knee instability is being evaluated for corrective osteotomy. A close-up of their weight-bearing knee radiograph is shown below. According to the Paley Method, which

Accepted Answer

An abnormally high Joint Line Convergence Angle (JLCA) opening laterally

Question 3

A 48-year-old patient presents with a symptomatic genu varum deformity and confirmed significant lateral collateral ligament (LCL) laxity, leading to a varus thrust. Following the Paley Method, the orthopedic surgeon plans a proximal tibial osteotomy

Accepted Answer

To decrease the adduction moment by shifting the mechanical axis into the healthy lateral compartment

Question 4

A 30-year-old patient with a history of Blount's disease presents with progressive knee pain and a significant varus deformity. A full-length weight-bearing radiograph is shown below. Based on the Paley Method, if the mLDFA is measured at 87° and the

Accepted Answer

Proximal tibia

Question 5

The case describes the pathomechanics of ligamentous failure in a malaligned knee. In a patient with a chronic genu varum deformity originating from a proximal tibial varus, which of the following best describes the long-term biomechanical consequenc

Accepted Answer

Constant, abnormal tensile stress leading to plastic deformation and attenuation

Question 6

A surgeon is planning a corrective osteotomy for a patient with a complex varus deformity. The diagram below illustrates the intersection of the proximal and distal mechanical axes of a deformed bone. According to the Paley Method, what does the poin

Accepted Answer

The Center of Rotation of Angulation (CORA)

Question 7

A 68-year-old female presents with severe medial compartment osteoarthritis, a 20mm medial Mechanical Axis Deviation (MAD), and a 7° laterally open Joint Line Convergence Angle (JLCA) on weight-bearing radiographs. She also exhibits a significant var

Accepted Answer

Perform a proximal tibial osteotomy to intentionally overcorrect the limb into 3-5 degrees of mechanical tibiofemoral valgus.

Question 8

The case describes a 'devastating and rapidly accelerating vicious cycle' in the context of knee malalignment and ligamentous laxity. Which of the following sequences accurately represents this cycle?

Accepted Answer

Asymmetric loading → Cartilage wear/meniscal degradation → Soft tissue attenuation → Deformity worsens

Question 9

A 40-year-old patient presents with a 15mm medial Mechanical Axis Deviation (MAD) and a normal Mechanical Lateral Distal Femoral Angle (mLDFA) of 88°. On weight-bearing radiographs, the Joint Line Convergence Angle (JLCA) is measured at 1° of medial

Accepted Answer

Proximal tibial varus deformity

Question 10

According to the Paley Method, when correcting a varus knee with severe LCL laxity, the surgeon deliberately creates a 'secondary compensatory deformity.' What is the ultimate functional outcome achieved by this intentional bony overcorrection?

Accepted Answer

To physically prevent the joint from thrusting open and provide dynamic joint stability

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

Orthopedic Board Review Questions: ABOS Part I, AAOS OITE, Paley Method, Varus Knee, LCL Laxity | Part 22010

Key Takeaway