ABOS Part I Comprehensive Review - Batch 4

Question 1

A 32-year-old male sustains a comminuted mid-shaft femoral fracture. The orthopedic surgeon is considering an intramedullary nail for fixation. To maximize the nail's resistance to bending and torsional forces without changing the material, which geo

Accepted Answer

Area Moment of Inertia

Question 2

An 80-year-old female with severe osteoporosis presents with a low-energy transverse subtrochanteric femoral fracture. Compared to a healthy young adult's femur, the osteoporotic bone's reduced resistance to bending, leading to this fracture, is prim

Accepted Answer

Area Moment of Inertia of the bone cross-section

Question 3

A biomechanical engineer is evaluating two designs for a new generation of intramedullary nails for tibial fractures. Nail A is a solid rod with a 10mm diameter. Nail B is a cannulated rod with an outer diameter of 12mm and an inner diameter of 8mm.

Accepted Answer

Nail B, due to its larger outer diameter and material distribution

Question 4

A 45-year-old patient is undergoing rehabilitation after a tibial shaft fracture treated with intramedullary nailing. The physical therapist emphasizes the importance of progressive weight-bearing exercises. From a biomechanical perspective, what is

Accepted Answer

Remodeling of bone to increase its Area Moment of Inertia

Question 5

A surgeon is performing an open reduction and internal fixation of a transverse femoral shaft fracture. To optimize the bone-plate construct's resistance to the anticipated primary bending forces, where should the plate ideally be positioned on the b

Accepted Answer

On the tension side of the bone, relative to the anticipated primary bending load

Question 6

A 7-year-old child sustains a comminuted tibia fracture requiring external fixation. The surgeon aims to maximize the bending stiffness of the external fixator frame. Which component of the fixator provides the greatest opportunity for optimization r

Accepted Answer

The distance between the connecting bar and the bone axis

Question 7

When analyzing the biomechanics of a pedicle screw construct in the spine, how does increasing the diameter of a pedicle screw influence the overall stiffness of the construct against bending forces?

Accepted Answer

Increases stiffness exponentially due to its effect on the Area Moment of Inertia

Question 8

During fracture healing, a bridging callus forms around the fracture site. The progressive increase in the mechanical stability of the healing construct is directly proportional to the increase in which geometric property of the callus?

Accepted Answer

Its Area Moment of Inertia

Question 9

A 60-year-old patient undergoes internal fixation of a femoral shaft fracture with a very stiff, large-diameter intramedullary nail. After 18 months, radiographs show significant cortical thinning around the implant, despite fracture union. This phen

Accepted Answer

Its Area Moment of Inertia

Question 10

A 55-year-old male presents with a pathological fracture of the humerus through a large lytic lesion identified as metastatic carcinoma. The bone's significantly weakened resistance to bending and torsion at the lesion site is primarily a consequence

Accepted Answer

A dramatic reduction in the Area Moment of Inertia at the lesion site

Orthopaedic Surgery Board Exam Review: ABOS Part I & AAOS OITE Prep Questions | Part 22210

ABOS Part I Orthopedic Review: Biomechanics, Fracture Fixation & Trauma | Part 22143

Key Takeaway