ABOS Part I Comprehensive Review - Batch 52

Question 1

A 60-year-old male presents with progressive right knee pain. A standing long-leg alignment radiograph reveals a mechanical axis that passes 15mm medial to the center of the knee joint. Which of the following best describes this patient's alignment a

Accepted Answer

Varus malalignment, leading to medial compartment overload.

Question 2

A 55-year-old female presents with a symptomatic varus knee deformity. Long-leg radiographs show a Mechanical Lateral Distal Femoral Angle (mLDFA) of 88° and a Medial Proximal Tibial Angle (MPTA) of 80°. Based on these measurements, where is the prim

Accepted Answer

Proximal tibia

Question 3

A surgeon is planning a pure angular correction of a diaphyseal tibial deformity. The preoperative plan identifies the Center of Rotation of Angulation (CORA) at the mid-diaphysis. To achieve the ideal pure correction without unintended translation,

Accepted Answer

Osteotomy at CORA, ACA at CORA.

Question 4

A 30-year-old patient requires correction of a severe valgus deformity of the distal femur. The CORA is located within the distal femoral epiphysis, making an osteotomy directly at the CORA impractical due to limited space for fixation. The surgeon p

Accepted Answer

A pure angular correction will be achieved, but with obligatory translation at the osteotomy site.

Question 5

A resident surgeon attempts to correct a proximal tibial varus deformity. They perform an osteotomy 3 cm distal to the CORA and place the external fixator hinge (ACA) 2 cm proximal to the CORA. Upon correction of the angular deformity, the post-opera

Accepted Answer

Osteotomy Rule 3: The Unintended Secondary Deformity.

Question 6

A 40-year-old male undergoes a high tibial osteotomy for medial compartment osteoarthritis. The surgeon corrects a varus deformity by performing an opening wedge osteotomy. To achieve optimal biomechanical stability and promote healing, the plate sho

Accepted Answer

The convex (lateral) side, leveraging the tension band principle.

Question 7

During a complex oblique osteotomy of the tibia, the surgeon aims to maximize interfragmentary compression and neutralize shear forces. Which of the following techniques, as described in the case, would be most effective in achieving this goal?

Accepted Answer

Applying an independent lag screw perpendicular to the osteotomy line.

Question 8

A patient requires a proximal tibial osteotomy for a complex deformity that necessitates a specific amount of translation to restore the mechanical axis, as per Paley's Rule 2. Which specialized plate design is specifically engineered to accommodate

Accepted Answer

A step plate.

Question 9

A 25-year-old patient presents with a severe valgus deformity of the proximal femur, characterized by a Lateral Proximal Femoral Angle (LPFA) of 75°. The surgeon plans a varus osteotomy to correct this. Which type of hardware is specifically highligh

Accepted Answer

A blade plate.

Question 10

The provided long-leg alignment radiograph shows a patient with a lower extremity deformity. Based on the principles discussed in the case, if the mechanical axis in this image passes significantly medial to the center of the knee joint, which of the

Accepted Answer

The limb exhibits varus malalignment, leading to medial compartment overload, and the next step is to pinpoint the deformity using joint orientation angles.

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

ABOS Part I & OITE Orthopedic Deformity Correction Review | Paley's Principles & Limb Alignment Questions | Part 22013

Key Takeaway