1. General Principles & Basic Science MCQs

A 72-year-old woman is prescribed romosozumab, a monoclonal antibody, for the treatment of severe postmenopausal osteoporosis. What is the primary molecular mechanism by which this medication exerts its osteoanabolic effect?

Which of the following best describes the fundamental biochemical changes that occur in the extracellular matrix of early osteoarthritic articular cartilage, as compared to the changes seen in normal aging articular cartilage?

A 25-year-old man sustains a mid-shaft humerus fracture resulting in a complete radial nerve palsy. Three weeks later, an electromyogram (EMG) reveals fibrillation potentials and positive sharp waves in the brachioradialis. Which of the following pathophysiologic changes at the cellular level best explains these electrodiagnostic findings?

A 45-year-old male falls from a ladder and sustains an acetabular fracture. The CT scan demonstrates a transverse fracture line across the acetabulum with a large, comminuted posterior wall fragment. The femoral head is subluxated posteriorly. The surgeon plans for open reduction and internal fixation. Which surgical approach provides the most direct access for anatomic reduction and plating of the involved columns in this fracture pattern?

A 65-year-old woman undergoes open reduction and internal fixation of a 3-part proximal humerus fracture using a lateral deltoid-splitting approach and a locking plate. Postoperatively, she demonstrates a positive Hornblower's sign (inability to actively maintain external rotation of the arm in 90 degrees of abduction). Which nerve is most likely to have been injured?

A 50-year-old woman is scheduled for open reduction and internal fixation of a medial tibial plateau fracture with posterior extension (Moore type I). The surgeon elects to use a posteromedial approach to the knee. The standard surgical interval for this approach is developed between which of the following two structures?

A 65-year-old woman with a 10-year history of alendronate use presents with a 3-month history of dull, aching right thigh pain. Plain radiographs reveal localized periosteal thickening of the lateral cortex of the subtrochanteric femur with a subtle transverse radiolucent line, but no complete fracture. What is the most appropriate prophylactic management?

A 65-year-old woman with a history of osteoporosis and 7 years of alendronate therapy presents with progressively worsening thigh pain. Radiographs reveal a transverse, non-comminuted fracture of the lateral cortex of the subtrochanteric femur with localized periosteal thickening ('beaking'). What is the most appropriate prophylactic surgical treatment?

A 45-year-old male is undergoing closed reduction and percutaneous pinning for a displaced proximal humerus fracture. To minimize the risk of injury to the axillary nerve, lateral pins should be inserted avoiding a specific zone. The axillary nerve typically courses transversely at what distance distal to the lateral edge of the acromion?

A 42-year-old female sustains a transverse posterior wall acetabular fracture. Radiographs and CT demonstrate a large posterior wall fragment and a medially displaced transverse component. The surgeon selects a Kocher-Langenbeck approach for fixation. During the procedure, the surgeon attempts to access the anterior extent of the transverse fracture line. Which of the following anatomic structures represents the primary limitation to the anterior/superior extension of the Kocher-Langenbeck approach?

A 55-year-old man is involved in a motor vehicle collision and sustains an associated both-column acetabular fracture. CT imaging demonstrates profound displacement of the anterior column, significant medial subluxation of the femoral head, and severe comminution of the quadrilateral plate. There is minimal displacement of the posterior column. Which of the following surgical approaches provides the most direct access for buttressing the quadrilateral plate to prevent medial subluxation?

A 40-year-old male sustains an isolated transverse acetabular fracture with a large, displaced posterior wall component. Preoperative computed tomography confirms the predominant displacement is posterior. Which surgical approach provides the most optimal visualization for direct reduction and fixation of this specific fracture pattern?

A 65-year-old female with a 10-year history of alendronate use presents with a 2-month history of insidious onset, aching pain in her right thigh. She denies any recent trauma. Radiographs of the right femur demonstrate a localized periosteal reaction with lateral cortical thickening and a transverse radiolucent line spanning approximately 30% of the lateral cortex in the subtrochanteric region. What is the most appropriate next step in management?

A 32-year-old male is evaluated in the emergency department after sustaining a closed spiral fracture of the distal third of the humeral shaft. His initial neurologic examination is completely intact. The fracture is managed with a closed reduction and application of a coaptation splint. Upon re-examination 30 minutes later, the patient is unable to extend his wrist or metacarpophalangeal joints, and has decreased sensation over the dorsal first web space. What is the most appropriate management of this neurologic deficit?

A 24-year-old man sustains a closed midshaft humerus fracture during an arm-wrestling match. On initial examination in the emergency department, his radial nerve motor and sensory functions are completely intact. A closed reduction is performed and a coaptation splint is applied. On post-reduction examination, the patient is unable to extend his wrist or fingers and has numbness in the first dorsal web space. What is the most appropriate next step in management?

A 45-year-old male undergoes open reduction and internal fixation of a transverse posterior wall acetabular fracture via a Kocher-Langenbeck approach. Postoperatively, the patient demonstrates a foot drop and inability to extend his toes. Which of the following intraoperative positioning or retraction errors most likely contributed to this complication?

A 72-year-old woman with a 10-year history of alendronate use presents with several weeks of vague, aching right thigh pain that worsens with weight-bearing. Radiographs reveal focal lateral cortical thickening ('cortical beaking') and a transverse radiolucent line extending partially through the lateral cortex in the subtrochanteric region of the right femur. What is the most appropriate management?

A 68-year-old active female presents with an anterior shoulder dislocation and an associated displaced greater tuberosity fracture after a fall. Closed reduction of the shoulder is successful. Post-reduction radiographs confirm a concentrically located glenohumeral joint, but the greater tuberosity fragment remains displaced 12 mm superiorly. What is the most common nerve injury associated with this dislocation, and what is the appropriate management of the greater tuberosity?

A 60-year-old male sustains a hyperextension injury to his neck in a motor vehicle collision. On physical examination, he demonstrates profound weakness in his upper extremities (deltoids, biceps, hand intrinsics) but is able to move his lower extremities against gravity. He has variable sensory loss below the lesion. Which of the following accurately describes the anatomy and expected recovery of this specific spinal cord injury syndrome?