1. General Principles & Basic Science MCQs

A patient undergoes a primary total hip arthroplasty via the direct anterior approach. Postoperatively, she reports numbness and dysesthesia over the anterolateral aspect of her thigh. Which nerve was most likely injured, and what is its anatomic course relative to the surgical interval?

Which of the following manufacturing processes in highly cross-linked polyethylene (HXLPE) primarily contributes to the reduction of its mechanical yield strength and fatigue resistance compared to conventional polyethylene?

During a direct anterior approach for THA, the surgeon develops the superficial internervous plane. Between which two muscles is this superficial dissection performed?

During a posterior approach to the hip, retractors are placed to expose the posterior column and acetabulum. The patient subsequently develops a dense foot drop postoperatively. Which portion of the affected nerve is most vulnerable to stretch injury in this location and why?

A 55-year-old female undergoes a THA using an anterolateral (Watson-Jones) approach. Postoperatively, she demonstrates a pronounced Trendelenburg lurch. Injury to which nerve is most directly responsible for this clinical finding?

A direct anterior approach to the hip utilizes the internervous plane between the sartorius and the tensor fasciae latae (TFL). Proximal extension of this superficial dissection places which of the following nerves at greatest risk of injury?

A 70-year-old female presents with an intractable Trendelenburg gait 3 years after a primary THA via a lateral approach. MRI confirms a massive, retracted, and fatty-infiltrated tear of the gluteus medius and minimus. What is the most appropriate surgical reconstruction option?

During open reduction and internal fixation of a transverse posterior wall acetabular fracture utilizing the Kocher-Langenbeck approach, the knee is maintained in flexion and the hip in extension. This positioning is primarily utilized to protect which of the following structures?

A 72-year-old woman sustains a displaced 4-part proximal humerus fracture. Examination reveals loss of sensation over the lateral deltoid. Which nerve is most likely injured?

During an anterior intrapelvic (modified Stoppa) approach for an acetabular fracture, significant hemorrhage is encountered over the superior pubic ramus. Which of the following vascular structures is most likely injured?

A 21-year-old motorcyclist is thrown from his bike and presents with a massively swollen shoulder and a pulseless upper extremity. Radiographs show lateral displacement of the scapula and a widely displaced clavicle fracture. Which of the following is the most likely neurologic injury associated with this condition?

During the ilioinguinal approach for a transverse acetabular fracture, massive hemorrhage is encountered while dissecting near the superior pubic ramus. This bleeding is most likely due to injury of an anastomosis between which two vascular structures?

A 22-year-old male presents with a closed, distal-third humeral shaft fracture. He is neurologically intact on initial evaluation in the emergency department. Following closed reduction and placement of a coaptation splint, he exhibits a complete wrist drop and inability to extend his metacarpophalangeal joints. What is the most appropriate next step in management?

A 60-year-old female taking alendronate for 10 years presents with 3 months of lateral thigh pain. Radiographs reveal diffuse cortical thickening of the lateral subtrochanteric femur with a transverse radiolucent 'beak' on the lateral cortex extending halfway through the bone. What is the most appropriate management?

A 48-year-old male sustains a posterior hip dislocation in a motor vehicle collision. The dislocation is successfully reduced closed in the emergency department within 2 hours of the injury. What is the most significant long-term complication associated with this injury?

A 65-year-old male with a native hip sustains a low-energy anterior hip dislocation after a fall. Upon initial inspection in the emergency department, what is the typical clinical posture of the affected lower extremity?

A 35-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 weak ankle dorsiflexion and eversion, but normal plantarflexion. Which nerve was most likely injured during the procedure?

A 40-year-old man presents to the emergency department with a posterior hip dislocation and an associated posterior wall acetabular fracture following a dashboard injury. Which nerve is most commonly injured in this specific clinical scenario?

A 72-year-old female presents with thigh pain and a subsequent low-energy transverse femur fracture showing cortical thickening and a lateral cortical beak. She has been taking alendronate for 10 years. What is the primary underlying pathophysiology responsible for this specific fracture pattern?