ABOS Part I Comprehensive Review - Batch 25

Question 1

A 35-year-old male presents with a chronic, painful left hip dislocation following a childhood septic arthritis, resulting in a severe Trendelenburg gait. He is being evaluated for a Pelvic Support Osteotomy (PSO). Which of the following statements b

Accepted Answer

It establishes a stable, medialized bony fulcrum against the ischium, preventing hip adduction and tensioning the abductors.

Question 2

A 58-year-old patient presents with a chronically unstable, painful right hip following a Girdlestone resection arthroplasty performed 15 years prior for a periprosthetic infection. He ambulates with a severe Trendelenburg gait and significant limb s

Accepted Answer

Pelvic Support Osteotomy (PSO).

Question 3

Historically, single-level pelvic support osteotomies were largely abandoned due to significant complications. Dr. Paley's modern double-level PSO technique overcame these limitations. What was the primary biomechanical failure of the historical sing

Accepted Answer

Creation of severe knee valgus and unacceptable Mechanical Axis Deviation (MAD).

Question 4

A 40-year-old patient is undergoing preoperative planning for a double-level Pelvic Support Osteotomy for a chronically dislocated hip. Clinical examination reveals a maximum passive hip adduction of 50 degrees. During a single-leg stance test, the p

Accepted Answer

55 degrees

Question 5

During the planning of the proximal osteotomy for a Pelvic Support Osteotomy, a surgeon identifies a fixed hip flexion deformity (FFD) of 10 degrees and notes the characteristic external rotation of the femur when maximally adducted. To achieve optim

Accepted Answer

Extend the femur by 15 degrees and internally rotate to compensate for adduction-induced external torsion.

Question 6

A surgeon is meticulously planning a Pelvic Support Osteotomy. To accurately determine the ideal level for the proximal osteotomy, which specific radiograph is considered mandatory and provides the most crucial information?

Accepted Answer

Supine AP pelvis in maximum adduction (cross-legged view).

Question 7

During planning for the distal osteotomy of a double-level Pelvic Support Osteotomy, the calculated Center of Rotation of Angulation (CORA) is found to be in the proximal diaphysis, which is deemed suboptimal for external fixator application and rege

Accepted Answer

The distal segment must be translated medially by approximately one half-shaft thickness.

Question 8

A patient undergoing a double-level Pelvic Support Osteotomy requires both limb lengthening and angular correction at the distal osteotomy site using an Ilizarov external fixator. According to Ilizarov principles as described in the case, what is the

Accepted Answer

Lengthen the limb first along its anatomical axis, then perform angular correction through the regenerate.

Question 9

Following a successful double-level Pelvic Support Osteotomy, a patient is undergoing rehabilitation. Which of the following kinematic changes would be an expected and desirable outcome of the procedure?

Accepted Answer

Elimination of the Trendelenburg gait and correction of lumbar hyperlordosis.

Question 10

A 28-year-old patient has undergone a double-level Pelvic Support Osteotomy for a chronically dislocated hip. Postoperative radiographs are being reviewed to assess the success of the correction.Referring to the provided image (specifically diagram '

Accepted Answer

To ensure the final mechanical axis, drawn from the new pelvic pivot point to the ankle center, passes directly through the center of the knee.

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

ABOS Part I Orthopaedic Review: Paley Deformity Correction, Pelvic Support Osteotomy & Hip Principles | Part 21918

Key Takeaway