ABOS Part I Comprehensive Review - Batch 39

Question 1

A 62-year-old male presents with progressive right knee pain, worse with activity. Standing full-length radiographs reveal a mechanical axis that passes 15 mm medial to the center of the knee joint. The mLDFA is measured at 87°, and the MPTA is 80°.

Accepted Answer

The primary deformity is a proximal tibial varus, indicating a potential need for a high tibial osteotomy.

Question 2

A 35-year-old male sustained a tibial shaft fracture 5 years ago, which healed with a significant angular deformity. He now presents with chronic knee pain and instability. A full-length standing radiograph reveals a complex deformity in the tibia. T

Accepted Answer

It is the Center of Rotation of Angulation (CORA), the ideal location for a pure angular correction osteotomy.

Question 3

A 58-year-old female presents with severe medial compartment osteoarthritis of the right knee. Full-length standing radiographs confirm a significant varus malalignment. The image provided demonstrates the effect of increasing varus angulation on kne

Accepted Answer

Concentration of supraphysiologic loads onto a smaller contact area of articular cartilage, leading to degradation.

Question 4

A 40-year-old male presents with chronic ankle pain and progressive stiffness following a malunited distal tibial fracture 3 years prior. Radiographs reveal a distal tibial recurvatum deformity. The image provided demonstrates the biomechanical conse

Accepted Answer

Anterior translation of the talus, leading to uncovering and focal posterior loading.

Question 5

A 70-year-old female presents with end-stage medial compartment osteoarthritis of the left knee and a history of a malunited mid-diaphyseal femoral fracture from 20 years ago. Full-length standing radiographs confirm a significant extra-articular fem

Accepted Answer

Perform a corrective osteotomy of the femur to restore the mechanical axis, followed by a staged TKA.

Question 6

A 28-year-old active duty soldier presents with chronic right knee pain and a feeling of instability, particularly during cutting maneuvers. Clinical examination reveals a varus thrust during gait. Full-length standing radiographs show a 7-degree var

Accepted Answer

Lateral collateral ligament (LCL) attenuation.

Question 7

A 55-year-old male with a history of a malunited distal tibial fracture now presents with progressive ankle pain. Radiographs show a distal tibial varus deformity. The subtalar joint is noted to be stiff due to post-traumatic arthrofibrosis. The imag

Accepted Answer

The lack of subtalar compensation will lead to direct transmission of abnormal forces to the ankle mortise, accelerating tibiotalar arthrosis.

Question 8

A 48-year-old female presents with chronic knee pain. Radiographs show a mechanical axis that passes 10 mm lateral to the center of the knee joint. The mLDFA is 80°, and the MPTA is 87°. The Joint Line Convergence Angle (JLCA) is 1°. Which of the fol

Accepted Answer

The patient has a distal femoral valgus deformity, leading to lateral compartment overload.

Question 9

A 68-year-old male with a long-standing history of severe varus knee deformity is being evaluated for total knee arthroplasty. He reports a 'wobble' in his knee during walking. Clinical examination reveals a significant lateral thrust during the stan

Accepted Answer

Initial varus deformity, followed by medial meniscectomy, then lateral collateral ligament laxity.

Question 10

A 30-year-old male presents with anterior knee pain and crepitus, particularly when ascending stairs. He has a known history of a congenital valgus deformity of the right lower extremity. Radiographs confirm a significant valgus alignment. Based on t

Accepted Answer

Lateral patellar facet.

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

Comprehensive ABOS Part I Orthopedic Surgery Board Exam Review: Deformity Correction & Biomechanics | Part 22007

Key Takeaway