Lower Extremity 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?

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 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?

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 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?

Paley's Malalignment Test is used to systematically evaluate lower extremity deformity. If a patient presents with a medial mechanical axis deviation (MAD) of 30 mm, a normal mechanical lateral distal femoral angle (mLDFA) of 88°, a normal medial proximal tibial angle (MPTA) of 87°, and an abnormal joint line convergence angle (JLCA) of 8°, what is the primary source of the varus deformity?

A 45-year-old female presents with bilateral knee pain. A full-length standing radiograph reveals a Mechanical Axis Deviation (MAD) of 20 mm medial to the center of the knee. The mechanical Lateral Distal Femoral Angle (mLDFA) is 95 degrees, and the Medial Proximal Tibial Angle (MPTA) is 87 degrees. What is the primary source of her malalignment?

When evaluating sagittal plane alignment of the tibia according to Paley's principles, the Posterior Proximal Tibial Angle (PPTA) is measured. What is the normal anatomical value of the PPTA, and what does it represent?

A 40-year-old male presents with a progressive genu valgum deformity. A long-leg AP radiograph shows a Mechanical Axis Deviation (MAD) passing 10 mm lateral to the center of the knee. Further analysis using the Malorientation Test (MOT) reveals an MPTA of 87° (normal 85°-90°) and a JLCA of 1° (normal 0°-2°). However, the Mechanical Lateral Distal Femoral Angle (mLDFA) is measured at 95° (normal 85°-90°). Where is the primary source of this patient's frontal plane deformity?

During preoperative planning for a distal femoral varus deformity, the surgeon identifies the intersection of the proximal and distal mechanical axes, defining the CORA. A transverse line is then drawn that perfectly bisects the angle of deformity at this intersection. What is the primary significance of this bisector line in Paley's system?

During the planning phase for a distal femoral valgus deformity, the surgeon draws the proximal and distal mechanical axes on a full-length radiograph, a critical step in the geometric approach to deformity correction.

A patient presents with genu valgum, and radiographic analysis reveals a deformity primarily in the distal femur. The surgeon is measuring the distal femoral mechanical angle (DFMA) as part of the frontal plane analysis.

A 42-year-old patient with a distal femoral varus deformity is undergoing preoperative planning. The surgeon has drawn the distal femoral joint line and the femoral mechanical axis. To assess the angular relationship of the knee joint to the femoral mechanical axis, which critical angle should be measured, and what is its normal average value?

A 30-year-old patient presents with a severe valgus deformity of the left lower extremity, as depicted in the provided full-length standing AP radiograph. After drawing the Proximal Mechanical Axis (PMA) and Distal Mechanical Axis (DMA), the surgeon identifies a single intersection point (CORA) that aligns perfectly with the visible apex of the deformity in the distal femur. Based on the Paley method, what does this finding signify regarding the deformity, and what are its implications for surgical planning?

A 16-year-old male presents with a progressive genu varum deformity following a physeal injury. A full-length standing AP radiograph is obtained, as shown below. The surgeon measures the Mechanical Lateral Distal Femoral Angle (mLDFA) as 78 degrees and the Medial Proximal Tibial Angle (MPTA) as 87 degrees. Based on these measurements and the normal values provided in the case, what is the primary location of the angular deformity?

A 45-year-old male presents with genu varum. Long-leg standing radiographs show a mechanical axis deviation (MAD) passing 25 mm medial to the knee center. The mechanical lateral distal femoral angle (mLDFA) is 88 degrees, and the medial proximal tibial angle (MPTA) is 80 degrees. What is the primary location of the deformity?

Radiographic evaluation of the distal femur in the sagittal plane utilizes the posterior distal femoral angle (PDFA). What is the normally accepted value for the PDFA?

A 16-year-old male has a post-traumatic tibia vara. Radiographic analysis reveals a mechanical medial proximal tibial angle (MPTA) of 75 degrees (normal 85-90). To accurately identify the CORA, the surgeon must draw the mechanical axes. Which of the following best defines the mechanical axis of the tibia?

A 45-year-old male has severe genu varum with a mechanical axis deviation (MAD) of 45 mm medial to the knee center. The mechanical lateral distal femoral angle (mLDFA) is 88° and the medial proximal tibial angle (MPTA) is 87°. The joint line convergence angle (JLCA) is 8°. What is the primary source of his varus MAD?