1. General Principles & Basic Science MCQs

Bone Morphogenetic Protein 2 (BMP-2) is utilized in orthopedic surgery to enhance bone healing, particularly in open tibial shaft fractures. BMP-2 initiates the osteoinductive signaling cascade by primarily binding to which type of cell surface receptor?

During the normal human gait cycle, eccentric muscle contraction is vital for shock absorption and controlled deceleration. In which phase of the gait cycle does the tibialis anterior reach its peak electromyographic (EMG) activity?

An anterior cruciate ligament (ACL) graft subjected to a constant physiological load over a prolonged period demonstrates a gradual and progressive increase in length. Which biomechanical property of viscoelastic materials does this describe?

Articular cartilage is structurally divided into four distinct zones. Which of the following best describes the characteristics of the superficial (tangential) zone?

A 55-year-old female presents with an atrophic nonunion of the humeral shaft six months post-injury. She admits to taking high-dose nonsteroidal anti-inflammatory drugs (NSAIDs) daily for osteoarthritis since her fracture. How do NSAIDs primarily impair fracture healing?

To maintain a bloodless field during an open reduction and internal fixation of an ankle fracture, a pneumatic tourniquet is applied. To minimize the risk of irreversible ischemic nerve injury and muscle necrosis, what is the maximum recommended continuous inflation time?

During the administration of an axillary brachial plexus block using 0.5% bupivacaine, the patient suddenly develops circumoral numbness, tinnitus, followed by ventricular arrhythmias. What is the primary cellular mechanism responsible for the cardiotoxicity in local anesthetic systemic toxicity (LAST)?

A patient sustains a severe traction injury to the peroneal nerve during a knee dislocation. Subsequent exploration demonstrates a Sunderland third-degree nerve injury. Which of the following accurately describes the histological state of the nerve?

Lubricin (Proteoglycan 4) plays a critical role in the boundary lubrication of articular cartilage, preventing wear under high load conditions. Which cells are primarily responsible for synthesizing and secreting lubricin?

The menisci of the knee provide critical load-sharing and joint stability functions. Following a peripheral tear, what is the primary source of nutrition and healing potential for the outer one-third (red-red zone) of the adult meniscus?

Massive cortical bone allografts are often used in limb salvage surgery for bone tumors. Compared to cancellous bone autografts, which of the following statements best characterizes the incorporation process of a cortical bone allograft?

Orthopedic surgeons are frequently exposed to ionizing radiation during fluoroscopy. According to the United States Nuclear Regulatory Commission (NRC), what is the maximum permissible annual occupational dose limit for whole-body radiation exposure?

Skeletal muscle function is dictated by the type of contraction performed. Which type of muscle contraction is defined by muscle lengthening under tension and is capable of generating the greatest maximal force?

Denosumab is highly effective in the management of postmenopausal osteoporosis and is also utilized to treat unresectable giant cell tumors of bone. It exerts its therapeutic effect by specifically binding to and neutralizing which of the following targets?

A 32-year-old male sustains a transverse midshaft radius fracture treated with a dynamic compression plate providing absolute stability. By which of the following mechanisms will this fracture primarily heal?

The microarchitecture of articular cartilage is highly organized to withstand complex mechanical forces. In which zone of articular cartilage are the collagen fibers oriented parallel to the joint surface to primarily resist shear stress?