ABOS Part I Comprehensive Review - Batch 35

Question 1

A 55-year-old male presents with chronic knee pain and difficulty ambulating due to a 'bent knee' that he cannot straighten. Clinical examination reveals a fixed flexion deformity (FFD) of 25 degrees. Radiographic analysis confirms a significant sagi

Accepted Answer

It forces the knee into a functional fixed flexion deformity, requiring increased quadriceps effort and leading to early joint degeneration.

Question 2

A 30-year-old athlete presents with a history of chronic knee pain and a subtle gait abnormality. On physical examination, the knee appears to 'lock' securely in full extension during the stance phase of gait without significant quadriceps effort. Ba

Accepted Answer

The mechanical axis passes slightly anterior to the center of the knee joint, creating a passive extension moment.

Question 3

A 60-year-old patient presents with a long-standing history of a 'bent knee' deformity. Clinical examination reveals a fixed flexion deformity (FFD) of 15 degrees. Full-length weight-bearing lateral radiographs show a true osseous femoral procurvatum

Accepted Answer

The patient has 10 degrees of compensatory joint hyperextension due to stretching of the posterior capsule.

Question 4

A 40-year-old patient with a history of femoral procurvatum is being evaluated for surgical correction. The surgeon is concerned about potential postoperative hyperextension. The provided case highlights the 'neuromuscular feedback loop' and the role

Accepted Answer

They serve as a 'dynamic checkrein,' receiving efferent signals from the CNS to prevent hyperextension.

Question 5

A 28-year-old patient with a history of poliomyelitis presents with a 35-degree femoral procurvatum and a clinical fixed flexion deformity (FFD) of 20 degrees, indicating 15 degrees of compensatory hyperextension. The patient has significant hamstrin

Accepted Answer

Perform a deliberate under-correction of the osseous deformity (e.g., 20 degrees) to utilize the remaining bony deformity as a mechanical block against hyperextension.

Question 6

A 48-year-old patient is undergoing preoperative planning for a sagittal plane knee deformity correction. The surgeon is following Dr. Paley's radiographic protocol. Which of the following is the MOST critical requirement for obtaining high-quality,

Accepted Answer

The patient must stand with the knee in the maximum possible extension, even if it's a flexed or hyperextended position.

Question 7

A 35-year-old patient presents with a 'bent knee' deformity. Radiographic analysis is performed using Paley's method.The surgeon measures the angle between the anatomical axis of the femur and the distal femoral joint line (tangent to the most poster

Accepted Answer

Posterior Distal Femoral Angle (PDFA); indicates anterior bowing of the distal femur (procurvatum).

Question 8

A 50-year-old patient presents with a functional knee flexion deformity. Radiographic analysis using Paley's method reveals a normal Posterior Distal Femoral Angle (PDFA) of 82 degrees. However, the angle between the anatomical axis of the tibia and

Accepted Answer

Posterior Proximal Tibial Angle (PPTA); indicates an excessive posterior slope of the tibial plateau (tibial procurvatum).

Question 9

A 42-year-old patient presents with a chief complaint of a 'bent knee' that will not straighten. Clinical examination reveals a maximum active and passive knee extension locked at 20 degrees of flexion (clinical FFD = 20°). Full-length weight-bearing

Accepted Answer

Osseous deformity: 30 degrees; Compensatory hyperextension: 10 degrees.

Question 10

A 65-year-old patient with a history of severe osteomyelitis in childhood presents with a significant tibial procurvatum deformity. Clinical examination reveals a marked knee flexion deformity and a gait pattern characterized by a 'crouch.'Based on t

Accepted Answer

The anterior bow of the proximal tibia increases the posterior slope of the tibial plateau, causing posterior subluxation of the femur.

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

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Key Takeaway