2. Trauma MCQs

When planning an intramedullary nailing for a patient with genu valgum, a surgeon must transition from mechanical axis planning to anatomic axis planning. In a typical adult femur, what is the approximate angle between the mechanical axis and the anatomic axis?

A 40-year-old patient undergoes an acute correction of a severe valgus deformity of the proximal tibia using a medial closing wedge osteotomy. Postoperatively, the patient develops a profound foot drop and inability to extend the hallux. What is the most critical anatomical consideration during this specific type of acute correction?

During a fixator-assisted nailing (FAN) of a distal tibial metaphyseal fracture malunion, what intraoperative technique is highly recommended to maintain the angular correction and prevent translation as the intramedullary nail is passed?

When evaluating the sagittal plane deformity of the tibia, a surgeon measures the posterior proximal tibial angle (PPTA). What is the normal anatomical reference value for the PPTA, and what does it signify?

A 24-year-old male presents with a multiplanar tibial deformity following a malunited fracture. According to Paley's Osteotomy Rule 1, if the osteotomy and the axis of correction of angulation (ACA/hinge) are both placed exactly at the Center of Rotation of Angulation (CORA), what is the expected result?

During preoperative planning for a distal femoral malunion, the surgeon realizes the osteotomy must be performed proximal to the actual CORA due to poor soft tissue quality. According to Paley's Rule 2, if the osteotomy is away from the CORA but the ACA (hinge) remains at the CORA, what will occur at the osteotomy site?

A 45-year-old female is evaluated for medial compartment knee osteoarthritis secondary to genu varum. Standing full-length radiographs reveal a mechanical axis deviation (MAD) of 35 mm medially. The mechanical lateral distal femoral angle (mLDFA) is 88 degrees, and the mechanical medial proximal tibial angle (mMPTA) is 75 degrees. The joint line convergence angle (JLCA) is 1 degree. Where is the primary source of the deformity?

In evaluating a full-length standing radiograph of a normal lower extremity, the mechanical axis line (center of femoral head to center of the ankle joint) normally passes through the knee at which location?

When performing a fibular osteotomy to facilitate a significant tibial deformity correction or lengthening, what is the optimal level for the fibular cut to minimize the risk of nonunion and neurologic injury?

A 16-year-old with a tibial shaft malunion requires corrective surgery. The preoperative planning identifies the Center of Rotation of Angulation (CORA) at the diaphyseal apex. If the surgeon ensures that both the osteotomy cut and the axis of correction of angulation (ACA) pass exactly through the CORA, what is the expected geometric outcome according to Paley's Rule 1?

A patient is managed with a hexapod external circular fixator (e.g., Taylor Spatial Frame) for a complex distal tibial nonunion with multiplanar deformity. The primary biomechanical advantage of this hexapod system over traditional Ilizarov frames is its ability to simultaneously manipulate how many independent degrees of freedom?

A 32-year-old patient with a history of severe lower extremity trauma presents with a varus deformity. Measurements show a medial proximal tibial angle (MPTA) of 87 degrees and a lateral distal femoral angle (LDFA) of 87 degrees. However, the joint line convergence angle (JLCA) is 9 degrees, diverging laterally. What is the most likely primary source of this patient's deformity?

A 35-year-old female presents with chronic lateral knee pain and a 'knock-kneed' appearance, consistent with a valgus deformity. A standing full-length AP radiograph reveals a Mechanical Axis Deviation (MAD) of 25mm lateral to the center of the knee. Further measurements show a Mechanical Lateral Distal Femoral Angle (mLDFA) of 75°, a Medial Proximal Tibial Angle (MPTA) of 87°, and a Lateral Distal Tibial Angle (LDTA) of 89°. Based on these findings, where does the primary angular deformity reside?

A 28-year-old male sustained a tibia shaft fracture that healed with a significant varus malunion. Preoperative planning is initiated using Paley's principles. After drawing the proximal and distal mechanical axis lines of the tibia, they intersect at a point located approximately 5 cm lateral to the bone shaft, in the soft tissue, at the level of the mid-diaphysis which appears radiographically straight. What is the most appropriate interpretation of this finding?

A 50-year-old male presents with a post-traumatic malunion of the distal femur, resulting in a complex valgus deformity. Initial mechanical axis planning reveals a 'resolved apex CORA' located in the mid-diaphysis, which appears straight. To accurately identify the true anatomic apices, the 'middle line' technique is employed, as illustrated in the diagram below. What is the primary purpose of drawing the yellow 'middle axis line' in this technique?

A 30-year-old patient with a history of tibia fracture malunion presents for deformity correction planning. A detailed knee radiograph, as shown, is used to assess joint orientation angles. If the measured Medial Proximal Tibial Angle (MPTA) is 80° and the Mechanical Lateral Distal Femoral Angle (mLDFA) is 87°, what is the most appropriate interpretation of these findings?

A 28-year-old patient presents with a significant varus deformity of the right lower extremity, confirmed by a medial Mechanical Axis Deviation (MAD) of 25mm. To precisely localize the segment(s) of deformity (femur, tibia, or both), which combination of angles should the surgeon prioritize measuring after the initial Mechanical Axis Test?

The case describes Dr. Dror Paley's principles as a 'monumental paradigm shift' in orthopedic surgery. Which of the following best encapsulates the fundamental change brought about by this systematic approach?

During a malalignment test on a patient with medial compartment knee osteoarthritis, the Joint Line Convergence Angle (JLCA) is measured at 6° (normal is 0-2°), opening laterally. The mLDFA and MPTA are both within normal limits. What is the most likely etiology of the mechanical axis deviation?

A patient with a healed complex tibia fracture presents with clinical varus. Radiographic planning using Paley's principles shows that the proximal and distal mechanical axes do not intersect at a single point within the bone. Instead, intersecting them with a mid-diaphyseal line creates two separate CORAs. This finding characterizes which type of deformity?