1. General Principles & Basic Science MCQs

A 55-year-old male requires open reduction for an irreducible posterior hip dislocation with a large posterior acetabular wall fracture. The surgeon opts for the Kocher-Langenbeck approach. During the deep dissection, as depicted in the illustration below, which critical neurovascular structure must be carefully identified and protected, typically by retracting it medially?

A 38-year-old male sustains a posterior hip dislocation. After successful closed reduction, he is noted to have a new-onset foot drop and weakness in ankle dorsiflexion and eversion. Sensation is diminished over the dorsum of the foot. This neurological deficit most likely involves which division of the sciatic nerve, and what is its typical prognosis?

A 60-year-old male with a history of traumatic brain injury (TBI) undergoes open reduction and internal fixation of a complex posterior hip dislocation with an acetabular fracture. Given his risk factors, which of the following prophylactic measures is most effective in preventing heterotopic ossification (HO)?

Which artery is now recognized as providing the predominant blood supply to the humeral head, contradicting historical anatomical teaching?

During a direct anterior approach for a total hip arthroplasty, the surgeon dissects the superficial interval between the sartorius and the tensor fasciae latae. Which nerve is at greatest risk of iatrogenic injury during this phase of the dissection?

An orthopedic surgeon is performing an ilioinguinal approach for an anterior column acetabular fracture. During dissection over the superior pubic ramus, brisk arterial bleeding is encountered. This is most likely due to an anastomosis between which two vascular systems?

When utilizing an anterolateral deltoid-splitting approach for locked plating of a proximal humerus fracture, which anatomic structure dictates the absolute safe distal extent of the deltoid split?

A 42-year-old male undergoes open reduction and internal fixation of a transverse posterior wall acetabular fracture via a Kocher-Langenbeck approach. Postoperatively, he exhibits a foot drop and inability to extend his great toe. Which specific nerve division is most susceptible to this iatrogenic injury?

A 55-year-old male sustains an anterior shoulder dislocation combined with a displaced greater tuberosity fracture. Prior to reduction, he has a loss of sensation over the lateral aspect of his shoulder. Injury to which of the following nerve roots primarily contributes to this specific sensory deficit?

During the ilioinguinal approach for an anterior column acetabular fracture, the surgeon operates through three distinct anatomical windows. Which structures define the lateral and medial borders of the middle window?

During a direct anterior approach for total hip arthroplasty, the superficial inter-nervous plane is developed between muscles innervated by which two nerves?

When performing a Kocher-Langenbeck approach for a posterior wall acetabular fracture, maintaining the hip in which position minimizes tension on the sciatic nerve?

Following a proximal humerus fracture, a patient demonstrates profound weakness in shoulder abduction and decreased sensation over the lateral deltoid. Through which anatomic space does the injured nerve typically exit the axilla?

During a modified Stoppa approach for anterior column acetabular fixation, the surgeon must identify the corona mortis. At what approximate distance from the pubic symphysis is this anastomosis typically located?

A 32-year-old male sustains an acetabular fracture demonstrating disruption of the ilioischial line and a large posterior wall fragment, with an intact iliopectineal line. Which surgical approach provides the most optimal access for reducing and fixing this specific fracture pattern?

During open reduction and internal fixation of an anterior column acetabular fracture via an ilioinguinal approach, massive hemorrhage is encountered while dissecting posterior to the superior pubic ramus. This bleeding is most likely originating from the corona mortis, an anastomosis between which two vascular structures?

A 30-year-old male sustains a posterior wall acetabular fracture with an associated posterior hip dislocation. On physical examination, he has a profound foot drop and inability to extend his toes. Which specific portion of the sciatic nerve is most commonly injured in this scenario, and what is its anatomic position within the greater sciatic notch?

The case highlights syndesmotic malreduction as the most critical complication. What is considered the gold standard imaging modality for assessing the accuracy of syndesmotic reduction in the postoperative period, given the limitations of plain radiographs?

A surgeon is considering fixation options for a complete syndesmotic disruption. According to recent randomized controlled trials, what is a proven advantage of dynamic flexible fixation (suture button) over static rigid screw fixation?

A 32-year-old male sustains a comminuted mid-shaft femoral fracture. The orthopedic surgeon is considering an intramedullary nail for fixation. To maximize the nail's resistance to bending and torsional forces without changing the material, which geometric property of the nail is most critical to optimize?