ABOS Part I Comprehensive Review - Batch 49

Question 1

A 55-year-old patient presents with a complex lower extremity deformity. Preoperative radiographs are obtained as shown below. Based on the provided case description and these images, which of the following statements best characterizes the primary d

Accepted Answer

The AP view (a) reveals severe genu valgum with a lateral mechanical axis deviation, while the lateral view (b) shows femoral procurvatum and tibial recurvatum, indicating multiple CORAs in both frontal and sagittal planes.

Question 2

A surgeon is planning to correct a complex, multi-apical femoral deformity involving both diaphyseal varus and distal metaphyseal valgus, along with significant procurvatum. Due to time constraints and a desire to minimize surgical invasiveness, the

Accepted Answer

The original angular deformity will be traded for a massive translational deformity, and the mechanical axis will remain malaligned, leading to biomechanical failure.

Question 3

Following a multi-level femoral osteotomy for severe valgus and procurvatum deformities, an intramedullary nail (IMN) is inserted. Postoperative radiographs, as shown in image (d) below, demonstrate the use of distal blocking screws. Given the preope

Accepted Answer

Blocking screws are placed on the lateral side of the nail path to maintain the varus correction by pushing the distal segment medially.

Question 4

A 30-year-old male presents with knee pain and a 'knock-kneed' appearance. Radiographic analysis reveals a Mechanical Lateral Distal Femoral Angle (mLDFA) of 80° and a Medial Proximal Tibial Angle (MPTA) of 95°. The Joint Line Convergence Angle (JLCA

Accepted Answer

The patient has a combined femoral valgus and tibial valgus deformity, with normal joint space.

Question 5

In the management of a patient with a profoundly complex, multi-apical femoral deformity and a complex tibial deformity, the surgical team decides to stage the procedures, addressing the femur first and the tibia in a secondary operation several week

Accepted Answer

It provides the surgeon an opportunity to dynamically adjust the subsequent tibial plan based on the femoral correction's outcome.

Question 6

A surgeon is planning a proximal tibial osteotomy for a patient with significant tibial valgus and recurvatum, complicated by poor bone stock. The goal is to achieve simultaneous multiplanar correction with minimal limb length change and maximal bone

Accepted Answer

A focal dome osteotomy, centered on the CORA, allowing multiplanar correction with a large congruent healing surface.

Question 7

During a Lengthening Over Nail (LON) procedure for a femoral deformity, the surgeon has performed the osteotomy and is preparing to insert the intramedullary nail. A critical step to ensure successful distraction and prevent jamming of the nail durin

Accepted Answer

To over-ream the medullary canal by 2 mm greater than the diameter of the nail to be inserted.

Question 8

A 40-year-old patient undergoes a proximal tibial osteotomy for severe genu valgum. The surgeon plans an acute valgus-to-varus correction. Based on the surgical pearls outlined in the case, what prophylactic measure is mandatory during this procedure

Accepted Answer

Prophylactic surgical decompression of the common peroneal nerve at the fibular neck.

Question 9

A 60-year-old patient with osteoporotic bone stock requires a complex tibial realignment using an external fixator, as depicted in the clinical image below. To maximize pin purchase and minimize the risk of pin loosening or bone failure in this compr

Accepted Answer

Utilizing hydroxyapatite (HA) coated half-pins to increase bone-to-pin integration.

Question 10

The mechanical axis is a fundamental concept in lower extremity deformity analysis. Which of the following statements accurately describes the mechanical axis and its significance in a healthy, well-aligned limb?

Accepted Answer

It is the true line of weight-bearing, drawn from the center of the femoral head to the center of the ankle plafond, and normally bisects the knee joint.

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

ABOS Part I & AAOS OITE Orthopedic Review: Deformity Correction, Paley's Laws & FAN | Part 21913

Key Takeaway