1. General Principles & Basic Science MCQs

In normal articular cartilage, which zone contains the highest concentration of proteoglycans, the lowest concentration of water, and collagen fibrils oriented perpendicular to the articular surface?

In the rehabilitation of Zone II flexor tendon repairs, which of the following suturing techniques biomechanically provides the greatest tensile strength and resistance to gap formation during early active motion protocols?

A 35-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic, epiphyseal lesion in the distal femur extending to the subchondral bone without a sclerotic border. Biopsy confirms Giant Cell Tumor of bone (GCT). If medical management is considered for a locally advanced and unresectable presentation, which medication specifically targets the pathogenesis of this tumor?

A resident is utilizing a ring external fixator for limb lengthening. Over the course of several days of continuous fixed distraction, the measurable force required by the tissue to maintain that specific distraction distance progressively decreases. Which viscoelastic property does this phenomenon represent?

During the ilioinguinal approach for an anterior column acetabulum fracture, significant hemorrhage occurs approximately 5 cm lateral to the pubic symphysis, directly on the posterior aspect of the superior pubic ramus. Which vascular anastomosis has most likely been injured?

Bone morphogenetic proteins (BMPs) play a crucial role in osteoinduction by binding to serine/threonine kinase receptors on mesenchymal stem cells. Following receptor activation, which of the following intracellular signaling molecules are directly phosphorylated and translocated to the nucleus to regulate gene transcription for osteoblast differentiation?

In the setting of an irreversible high radial nerve palsy, tendon transfers are utilized to restore wrist and digit extension. In the classic Boyes transfer to restore finger extension, which muscle is transferred to the extensor digitorum communis (EDC)?

During the non-operative management of a clubfoot using the Ponseti method, serial casting gradually stretches the contracted medial ligaments. The viscoelastic property allowing the ligament to progressively elongate under a constant, prolonged load over time is termed:

Denosumab has revolutionized the medical management of Giant Cell Tumor of bone (GCTB), particularly for unresectable or metastatic lesions. What is the specific molecular mechanism of action of this agent?

According to Perren's strain theory of bone healing, the mechanical environment dictates the type of tissue that forms within a fracture gap. What is the maximum theoretical amount of interfragmentary strain that can be tolerated to permit the formation of primary lamellar bone?

In the process of secondary bone healing, which of the following signaling molecules is a member of the TGF-beta superfamily and acts as a potent osteoinductive factor directly responsible for driving the differentiation of mesenchymal stem cells into osteoblasts?

A 35-year-old female presents with a recurrent giant cell tumor of the distal femur. The multidisciplinary tumor board recommends a trial of denosumab prior to surgical resection. What is the specific mechanism of action of this medication?

Bone morphogenetic proteins (BMPs) play a critical role in bone healing. Which of the following statements accurately describes the mechanism of action of BMP-2?

During an anterolateral (deltoid-splitting) approach for the open reduction and internal fixation of a proximal humerus fracture, which neurovascular structure is at highest risk if the dissection extends more than 5 cm distal to the lateral edge of the acromion?

Articular cartilage is structurally divided into four distinct zones. Which zone is characterized by the highest concentration of water, the lowest concentration of proteoglycans, and collagen fibers that run parallel to the articular surface?

Which of the following clinical scenarios of bone formation is predominantly driven by intramembranous ossification rather than endochondral ossification?

Following a Zone II flexor tendon repair of the index finger, a structured rehabilitation program is initiated. Biomechanical studies have shown that the strength of the tendon repair during the initial healing phase is most directly proportional to which of the following surgical factors?

The direct anterior approach to the hip (Smith-Petersen) exploits a true internervous and intermuscular plane. During the deep dissection, retractors are placed around the femoral neck. To minimize the risk of denervating the tensor fasciae latae (TFL), the surgeon must be careful to protect its nerve supply. Which nerve supplies the TFL, and where does it typically course in relation to this surgical approach?