2. Trauma MCQs

A 30-year-old patient is undergoing femoral lengthening with an external fixator. Radiographs at 5 weeks show an hourglass-shaped regenerate bone with widening of the radiolucent distraction gap. What is the most appropriate next step in management?

A 45-year-old male presents with medial knee pain. Weight-bearing radiographs show a varus mechanical axis deviation (MAD) 30 mm medial to the knee center. Measurements reveal a Mechanical Lateral Distal Femoral Angle (mLDFA) of 88 degrees and a Medial Proximal Tibial Angle (MPTA) of 75 degrees. Where is the primary source of the structural deformity?

During preoperative deformity planning for a patient with severe osteoarthritis and varus malalignment, the joint line convergence angle (JLCA) is measured at 6 degrees (normal is 0-2 degrees). What does an increased JLCA most likely indicate in this setting?

A 45-year-old male presents with symptomatic varus malalignment of the lower extremity. Full-length radiographs show a mechanical axis deviation (MAD) of 35 mm medial to the knee center. The mechanical lateral distal femoral angle (mLDFA) is 96 degrees, and the medial proximal tibial angle (MPTA) is 88 degrees. Where is the primary source of the deformity?

A 14-year-old boy is undergoing deformity correction with an external fixator.

He presents 4 weeks postoperatively with erythema, pain, and serous drainage around a proximal tibial half-pin. There is no systemic toxicity or radiographic loosening. What is the most appropriate initial management?

A surgeon is planning a complex lower extremity osteotomy for a patient with significant combined angulation and rotational deformity. While clinical examination provides initial insights into the torsional profile, what is considered the 'gold standard' imaging modality for the most precise, objective quantification of rotation, and what specific landmarks are typically used?

A 60-year-old patient presents with a distal femoral deformity. During preoperative planning, the surgeon measures the Mechanical Lateral Distal Femoral Angle (mLDFA) on a true AP view of the knee with the patella pointing forward. What is the normal range for the mLDFA, and what does it primarily define?

A 55-year-old patient presents with knee pain and a varus deformity. Full-length standing radiographs reveal a Mechanical Lateral Distal Femoral Angle (mLDFA) of 92° and a Medial Proximal Tibial Angle (MPTA) of 80°. The Joint Line Convergence Angle (JLCA) is 1°. Based on these measurements and Dr. Paley's principles, where is the primary source of the angular deformity located?

A 60-year-old patient undergoes a derotational osteotomy for a proximal femoral internal rotation deformity. The surgeon chooses to rotate the femur around its anatomic axis, as is often done with intramedullary nailing. Based on the unique biomechanics of femoral deformities and the provided diagram, what is the most likely immediate consequence of this surgical choice if no compensatory planning is performed?

A surgeon is planning a subtrochanteric derotational osteotomy for a patient with excessive femoral anteversion. While rotation around the mechanical axis is geometrically ideal, the case highlights a 'Proximal Femur Osteotomy Paradox.' What is the primary reason why surgeons are often 'forced by biology and hardware limitations' to perform rotational correction around the anatomic axis in the proximal femur, despite the known risks?

A 48-year-old patient presents with a combined femoral deformity requiring both angular and rotational correction. As part of the 'Definitive Preoperative Planning Protocol,' the surgeon obtains a 'Patella Forward Radiograph' (Knee Forward View). What is the primary and most accurate information derived from this specific radiographic view?

A 50-year-old patient requires correction of a complex femoral angulation-rotation deformity. The surgeon is following Dr. Paley's 'Definitive Preoperative Planning Protocol,' which involves using both a Patella Forward and a Hip Forward radiograph. The provided diagram illustrates a critical step in this protocol. What is the ultimate goal of the geometric transfer process depicted in the diagram?

In assessing a patient's sagittal plane deformity, the posterior distal femoral angle (PDFA) is measured on a lateral radiograph. What is the normal average value of the anatomic PDFA?

During limb lengthening using distraction osteogenesis, the Bone Healing Index (BHI) is often used to counsel patients on the expected duration of external fixation. How is the BHI defined?

A 45-year-old female presents with knee pain and a valgus deformity. During preoperative planning on a long-leg alignment film, the mechanical lateral distal femoral angle (mLDFA) is measured. What is the generally accepted normal value for the mLDFA?

A patient with advanced medial compartment knee osteoarthritis and a varus thrust has a long-leg radiograph showing significant mechanical axis deviation. The Joint Line Convergence Angle (JLCA) is measured at 6 degrees. What does this specific finding indicate?

A patient sustains a malunited segmental tibial fracture resulting in a multi-apical deformity. How are the multiple Centers of Rotation of Angulation (CORAs) geometrically determined on a single plane radiograph?

A 16-year-old male presents with a significant varus deformity of the right tibia following a previous malunited fracture. Preoperative templating identifies the Center of Rotation of Angulation (CORA). According to Paley's Rule 1 of Deformity Correction, what will be the anatomical result if both the osteotomy and the axis of correction (hinge) are placed exactly at the CORA?

A surgeon is planning a deformity correction for a mid-diaphyseal femoral malunion. Due to soft tissue constraints, the surgeon decides to perform the osteotomy at a level proximal to the Center of Rotation of Angulation (CORA), but sets the hinge (axis of correction) exactly at the CORA. Which of the following describes the resulting correction based on Paley's Rule 2?

During preoperative standing long-leg radiograph evaluation for a varus knee, the Joint Line Convergence Angle (JLCA) is measured. The normal JLCA is typically 0 to 2 degrees. A patient with a severe varus deformity has a JLCA measuring 7 degrees, diverging laterally. What does this abnormal JLCA primarily indicate?