1. General Principles & Basic Science MCQs

In orthopedic biomaterials, galvanic corrosion occurs when two electrochemically dissimilar metals are placed in physical contact within a conductive fluid environment (e.g., serum). Which of the following combinations of metals carries the highest risk of severe galvanic corrosion and is therefore contraindicated?

During the process of endochondral ossification, growth plate chondrocytes undergo a period of hypertrophy before programmed cell death and subsequent vascular invasion. Which of the following collagen types is predominantly and specifically synthesized by these hypertrophic chondrocytes to facilitate matrix mineralization?

A 24-year-old woman presents with worsening knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion extending to the subchondral bone of the distal femur. Biopsy reveals neoplastic mononuclear cells interspersed with numerous reactive multinucleated giant cells. If the tumor is deemed surgically unresectable, medical management with Denosumab is indicated. What is the precise molecular target of this medication?

A 55-year-old woman requires open reduction and internal fixation of a displaced volar Barton fracture. The surgeon elects to use the standard volar Henry approach to the distal radius. Which of the following anatomical intervals is utilized during the superficial dissection of this approach?

A 45-year-old man feels an acute pop in the back of his knee while performing a deep squat. MRI demonstrates a complete radial tear at the posterior root of the medial meniscus, with 4 mm of medial meniscal extrusion seen on the coronal sequence. Biomechanically, this specific injury is most functionally equivalent to which of the following?

During a Zone II flexor tendon repair, preserving the biomechanical advantage of the flexor sheath is critical to maintain functional excursion and limit bowstringing. Which two pulleys are most critical to preserve or reconstruct?

Bone morphogenetic proteins (BMPs) initiate osteogenesis by binding to serine-threonine kinase receptors. Which intracellular signaling molecules are directly phosphorylated by the BMP receptor complex and subsequently translocate to the nucleus to regulate gene expression?

A 32-year-old female presents with a lytic, eccentrically located epiphyseal lesion in the proximal tibia. Biopsy reveals mononuclear cells and multinucleated giant cells. Which of the following is the true neoplastic cell component and its characteristic receptor expression?

In total hip arthroplasty, the phenomenon where a hard third body (such as a bone fragment or bone cement) becomes embedded in the polyethylene liner and subsequently scratches the femoral head is best described as what type of wear?

According to Perren's strain theory of bone healing, primary bone healing (direct remodeling without callus) will only occur if the interfragmentary strain is below what threshold?

During the anterior approach to the pelvis (ilioinguinal approach) for fixation of an acetabular fracture, significant hemorrhage occurs near the superior pubic ramus. This is most likely due to injury of an anastomotic vessel connecting which two arterial systems?

According to Perren's strain theory of bone healing, primary (contact) bone healing without callus formation requires the interfragmentary strain to be maintained below what threshold?

Biomechanical studies of flexor tendon repairs in Zone II demonstrate that the ultimate tensile strength of the repair before gap formation is most directly proportional to:

Denosumab, a monoclonal antibody used in the treatment of recurrent or unresectable Giant Cell Tumor (GCT) of bone, exerts its therapeutic effect by targeting which of the following?

Articular cartilage is highly specialized to resist compressive forces. Which structural component of the extracellular matrix is primarily responsible for drawing water into the cartilage to provide this compressive stiffness via the Donnan osmotic effect?

During anterior pelvic ring surgery via a Pfannenstiel approach, significant bleeding is encountered posterior to the superior pubic ramus. Which two vessels form the most common anastomosis responsible for this bleeding (Corona Mortis)?

Which of the following combinations of orthopedic implant materials is most likely to result in significant galvanic corrosion when placed in direct contact within the human body?