1. General Principles & Basic Science MCQs

A 45-year-old male presents with the inability to actively extend his middle finger at the metacarpophalangeal (MCP) joint after a traumatic 'flicking' injury. On examination, he is able to maintain full MCP extension if the digit is passively extended by the examiner. There is focal swelling dorsally over the MCP joint. What is the primary anatomic structure injured?

A 60-year-old woman with a long-standing history of rheumatoid arthritis presents with a progressive inability to actively extend her ring and small fingers at the MCP joints. Passive extension is full and intact, but the tenodesis effect is absent. What is the underlying pathophysiology of her condition?

When evaluating the biomechanical principles of flexor tendon repair to allow for early active mobilization protocols, which of the following factors contributes most to the immediate mechanical strength of the repair site?

During digital replantation following an acute traumatic amputation, successful revascularization and functional outcomes depend on a systematic surgical approach. Which anatomical structure should ideally be repaired or stabilized first to provide a foundation for the remainder of the microsurgical reconstruction?

In optimizing a zone II flexor digitorum profundus (FDP) tendon repair to allow for early active motion protocols, which of the following technical modifications provides the greatest increase in the tensile strength of the repair?

A 40-year-old female complains of severe, excruciatingly localized pain under her thumbnail, which is exacerbated by cold weather. On physical examination, inflating a blood pressure cuff on her proximal arm temporarily relieves the pain in the digit. What is the name of this clinical sign?

A 30-year-old mechanic sustains a high-pressure injection injury to his non-dominant index finger while using an industrial sprayer. He presents to the emergency department 2 hours later. Which of the following factors is most strongly associated with an increased ultimate risk of amputation?

In the setting of traumatic amputations, ischemia time dictates the viability of the replantation. What is the generally accepted maximum cold ischemia time for replantation of an isolated completely amputated digit, compared to a major proximal limb amputation (e.g., at the proximal forearm)?

A 30-year-old chef sustains a volar laceration to the index finger. Surgical exploration reveals a 40% partial laceration of the flexor digitorum profundus (FDP) tendon in Zone II, with an intact flexor digitorum superficialis (FDS). What is the most appropriate management?

A 60-year-old female with long-standing rheumatoid arthritis is unable to actively extend her small and ring fingers at the metacarpophalangeal (MCP) joints. Passive extension is intact. The tenodesis effect does not produce active extension of these digits. What is the primary pathophysiology?

To minimize the recurrence rate when surgically treating a digital mucous cyst located at the distal interphalangeal (DIP) joint, which step is most essential?

A patient cannot fully flex their normal middle, ring, and small fingers after undergoing an index finger flexor digitorum profundus (FDP) tendon repair. What is the primary cause of this phenomenon?

A 32-year-old female presents with a painful, eccentrically located, purely lytic lesion in the proximal tibial epiphysis extending into the metaphysis. Biopsy reveals numerous multinucleated giant cells in a background of mononuclear stromal cells. For unresectable cases or to facilitate joint preservation, a targeted biologic agent can be used. What is the mechanism of action of this agent?

A 68-year-old man presents with dull low back pain and anemia. A technetium-99m bone scan is largely unremarkable, but subsequent radiographs reveal numerous discrete, 'punched-out' lytic lesions in the skull, spine, and pelvis. Which of the following best explains the false-negative finding on the bone scan?

A 72-year-old man presents with progressive hearing loss and increasing hat size. His serum alkaline phosphatase is markedly elevated, but calcium and phosphate levels are normal. Biopsy of a bowing tibial lesion reveals a mosaic pattern of lamellar bone with prominent cement lines. Which of the following treatments is the first-line pharmacologic therapy for symptomatic disease in this patient?

A 30-year-old female presents with a massive, unresectable giant cell tumor of bone (GCTB) located in her sacrum. Her oncologist initiates treatment with denosumab. Which of the following best describes the cellular mechanism of action of this targeted therapy?

A 65-year-old male is newly diagnosed with multiple myeloma presenting with diffuse osteolytic bone lesions. The pathogenesis of these purely lytic lesions is related to a profound uncoupling of bone remodeling, featuring both osteoclast activation and severe osteoblast inhibition. Overexpression of which of the following molecules by the neoplastic plasma cells is primarily responsible for the direct inhibition of osteoblastic bone formation?

A 55-year-old male presents with diffuse thigh pain. Radiographs show a permeative, poorly marginated lytic lesion in the femoral diaphysis with minimal periosteal reaction.

MRI reveals extensive marrow replacement extending far beyond the cortical changes. A biopsy is performed, showing sheets of atypical lymphoid cells that stain positively for CD20 and CD45. Assuming there is no impending fracture, what is the mainstay of treatment for this condition?