2. Trauma MCQs

A 25-year-old male sustains a diaphyseal fracture of the femur treated nonoperatively. He heals with normal mLDFA and normal proximal femur anatomy, but the distal mechanical axis is shifted 2 cm medially and remains perfectly parallel to the proximal mechanical axis. Where is the CORA located in this pure translational deformity?

A 40-year-old male complains of knee hyperextension during gait following a healed proximal third tibial fracture. Radiographs show a mechanical posterior proximal tibial angle (mPPTA) of 95° (normal 81°). This finding is most consistent with which of the following deformities?

During the distraction phase of a 6 cm tibial lengthening over an intramedullary nail (LON), the patient begins to complain of new-onset numbness on the dorsum of the foot and difficulty extending the great toe. What is the most appropriate immediate management?

A 42-year-old man requires correction of a severe midshaft tibial valgus deformity. The skin directly over the CORA is compromised due to prior trauma. The surgeon places the external fixator hinge at the CORA but performs the osteotomy 5 cm proximal to the CORA. What must happen at the osteotomy site to achieve a straight mechanical axis?

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 patient undergoing tibial lengthening via distraction osteogenesis mistakenly adjusts the frame at a rate of 2.0 mm per day for two weeks. What is the most likely complication of this error?

A 30-year-old male with a history of a complex tibial fracture presents with a multi-apical deformity. How is a multi-apical (double-level) diaphyseal deformity geometrically identified using Paley's method?

During routine follow-up 4 weeks after circular frame application for a tibial nonunion, a patient presents with erythema, mild tenderness, and minimal serous drainage at a single wire site. There is no wire loosening or signs of systemic infection. According to the Checketts-burns classification, what is the most appropriate initial management?

What defines a pure translational deformity in the context of Paley's principles of lower limb malalignment?

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?

A surgeon is performing a valgus-producing (varus-correcting) proximal tibial osteotomy on a patient with significant genu varum. As the correction is achieved, the surgeon is particularly mindful of a specific neurovascular structure that is at risk due to tethering. Which structure is of primary concern, and what prophylactic measure might be considered for large corrections?

A patient presents with a mid-shaft femoral deformity following a malunited fracture. The orthopedic surgeon, adhering to Paley's principles, is preparing for a comprehensive deformity analysis.

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?