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1. General Principles & Basic Science MCQs

Practice Set 562 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 11221

Topic: 1. General Principles & Basic Science

A 45-year-old male sustains a posterior root tear of the medial meniscus during a deep squat.

Biomechanically, what is the consequence of this specific injury on the tibiofemoral joint contact pressures if left untreated?

. A 10% increase in peak contact pressure
. Contact pressures shift entirely to the anterior compartment
. Peak contact pressures become equivalent to a knee with a total medial meniscectomy
. Contact area increases, decreasing overall peak pressure
. Peak contact pressures are unchanged due to the intact transverse intermeniscal ligament

Correct Answer & Explanation

. A 10% increase in peak contact pressure

Explanation

A medial meniscus posterior root tear disrupts the hoop stresses of the meniscus. Biomechanical studies have demonstrated that this extrusion results in medial compartment contact pressures and contact areas that are functionally equivalent to those seen after a total medial meniscectomy, leading to rapid chondrolysis.

Question 11222

Topic: 1. General Principles & Basic Science

A 28-year-old competitive weightlifter feels a 'pop' in his anterior axilla while performing a heavy bench press. MRI confirms a complete rupture of the pectoralis major tendon.

At the humeral insertion site, what is the spatial relationship of the sternocostal head relative to the clavicular head?

. The sternocostal head inserts anterior and proximal to the clavicular head
. The sternocostal head inserts posterior and proximal to the clavicular head
. The sternocostal head twists 180 degrees and inserts posterior and proximal to the clavicular head
. The sternocostal head twists 180 degrees and inserts posterior and distal to the clavicular head
. The sternocostal head twists 90 degrees and inserts anterior and distal to the clavicular head

Correct Answer & Explanation

. The sternocostal head inserts anterior and proximal to the clavicular head

Explanation

The pectoralis major consists of the clavicular and sternocostal heads. As the muscle fibers course laterally toward the humerus, the sternocostal head twists 180 degrees on itself, resulting in its insertion being posterior (deep) and proximal to the clavicular head insertion. This twisting puts the inferior fibers under maximum tension during the eccentric phase of a bench press, making them the most vulnerable to rupture.

Question 11223

Topic: 1. General Principles & Basic Science

A 32-year-old weightlifter feels a sudden pop in his anterior chest wall while performing a heavy bench press. He presents with a loss of the anterior axillary fold and ecchymosis extending down his arm. An MRI confirms a complete rupture of the pectoralis major tendon. Which of the following best describes the pathoanatomy and usual location of this specific injury?

. Avulsion of the clavicular head from its origin on the medial clavicle
. Tear at the musculotendinous junction of the sternal head
. Avulsion of the sternal head from its insertion on the humerus
. Avulsion of both heads from the coracoid process
. Intrasubstance rupture of the clavicular head tendon

Correct Answer & Explanation

. Avulsion of the clavicular head from its origin on the medial clavicle

Explanation

Pectoralis major ruptures most commonly occur during eccentric loading, such as the downward phase of a bench press. The most common site of failure is an avulsion of the sternal head from its insertion on the lateral lip of the bicipital groove of the humerus. The sternal head inserts deep and proximal to the clavicular head.

Question 11224

Topic: 1. General Principles & Basic Science

During surgical repair of an acute, complete pectoralis major rupture in a weightlifter, the surgeon must accurately identify and reattach the tendinous footprint. Which of the following statements correctly describes the anatomical relationship of the pectoralis major insertion on the humerus?

. The sternal head inserts deep and proximal to the clavicular head
. The clavicular head inserts deep and proximal to the sternal head
. Both heads blend into a single, uniform layer prior to insertion
. The sternal head inserts primarily onto the lesser tuberosity
. The clavicular head forms the posterior axillary fold

Correct Answer & Explanation

. The sternal head inserts deep and proximal to the clavicular head

Explanation

The pectoralis major tendon undergoes a 180-degree twist as it approaches its insertion on the lateral lip of the bicipital groove. Because of this twist, the inferior (sternocostal) fibers insert superiorly (proximally) and deep (posteriorly) to the superior (clavicular) fibers. The sternal head is the most commonly ruptured portion during eccentric loading activities like the bench press.

Question 11225

Topic: Infection, Pharmacology & VTE

A 19-year-old football player sustains a severe blunt trauma to his anterior thigh from a helmet collision. Three weeks later, he presents with significantly restricted knee flexion and a firm, painful mass in his quadriceps. Radiographs demonstrate peripheral calcification within the muscle belly. What is the most appropriate initial management for this condition?

. Immediate surgical excision of the mass to restore motion
. Aggressive passive stretching under regional anesthesia
. Extracorporeal shockwave therapy and deep tissue massage
. Rest, gentle active range of motion, and NSAIDs
. Intralesional corticosteroid injection followed by casting

Correct Answer & Explanation

. Immediate surgical excision of the mass to restore motion

Explanation

The patient has developed myositis ossificans traumatica following a severe quadriceps contusion. The hallmark radiographic finding at 3-4 weeks is peripheral maturation/calcification with a radiolucent center. Initial management is strict nonoperative care, including rest, gentle active (not passive) range of motion, and NSAIDs (like Indomethacin) to help halt further heterotopic bone formation. Aggressive passive stretching or massage can exacerbate the condition. Surgical excision is absolutely contraindicated in the acute/immature phase due to an extremely high risk of recurrence; it is only considered if the mass remains symptomatic after full maturation (typically 6-12 months).

Question 11226

Topic: 1. General Principles & Basic Science

A 45-year-old female marathon runner complains of recalcitrant lateral hip pain. Examination shows a positive Trendelenburg sign and pain with resisted hip abduction. MRI reveals a full-thickness tear of the gluteus medius at its insertion. To which facet(s) of the greater trochanter does the main tendon of the gluteus medius primarily attach?

. Anterior facet
. Lateral and superoposterior facets
. Posterior facet
. Anterior and inferior facets
. Tip of the greater trochanter exclusively

Correct Answer & Explanation

. Anterior facet

Explanation

The gluteus medius inserts primarily onto the lateral and superoposterior facets of the greater trochanter. The gluteus minimus inserts more anteriorly onto the anterior facet.

Question 11227

Topic: Surgical Anatomy & Approaches

A 45-year-old construction worker with chronic anterior shoulder pain undergoes an open subpectoral biceps tenodesis.

During the surgical approach, retractors are placed deep to the short head of the biceps and coracobrachialis (conjoined tendon). Which nerve is at greatest risk of injury with overly aggressive medial retraction in this specific area?

. Axillary nerve
. Musculocutaneous nerve
. Median nerve
. Ulnar nerve
. Radial nerve

Correct Answer & Explanation

. Axillary nerve

Explanation

The musculocutaneous nerve branches from the lateral cord and typically enters the coracobrachialis muscle approximately 5-8 cm distal to the coracoid process. Aggressive medial retraction of the conjoined tendon during a subpectoral biceps tenodesis places this nerve at significant risk of traction injury.

Question 11228

Topic: 1. General Principles & Basic Science

A 30-year-old runner complains of lateral knee pain that is particularly worse when running downhill.

Examination reveals tenderness exquisitely localized over the lateral femoral epicondyle. Which clinical test is most specific for confirming the diagnosis of Iliotibial Band Friction Syndrome?

. Ober's test
. Noble compression test
. McMurray test
. Pivot shift test
. Dial test

Correct Answer & Explanation

. Ober's test

Explanation

The Noble compression test is specifically designed to elicit the pain of Iliotibial (IT) Band Friction Syndrome. Pain is typically reproduced at approximately 30 degrees of knee flexion as the IT band snaps over the lateral femoral epicondyle while manual pressure is applied. Ober's test evaluates for IT band tightness but is not specific for recreating the pain of friction syndrome.

Question 11229

Topic: Biology, Genetics & Bone Healing

A 60-year-old female presents with atraumatic thigh pain. Radiographs reveal a transverse fracture of the lateral cortex of the subtrochanteric femur with focal cortical thickening. She has been on alendronate for 7 years. Following intramedullary nailing, what is the best medical management?

. Continue alendronate and add calcium/vitamin D
. Discontinue alendronate, start teriparatide, and ensure adequate calcium/vitamin D
. Discontinue alendronate, start denosumab
. Continue alendronate and start methotrexate
. Discontinue alendronate and start high-dose systemic corticosteroids

Correct Answer & Explanation

. Continue alendronate and add calcium/vitamin D

Explanation

For atypical femur fractures associated with prolonged bisphosphonate use, the medication should be immediately discontinued. Teriparatide, an anabolic agent, has been shown to aid in fracture healing in these clinical scenarios.

Question 11230

Topic: 1. General Principles & Basic Science

Following a primary repair of a Zone II flexor tendon injury in the index finger, a patient undergoes an early active mobilization protocol. What is the primary biomechanical advantage of this rehabilitation strategy compared to static immobilization?

. It decreases the tensile strength of the repair, preventing stiffness
. It increases extrinsic healing to the surrounding flexor sheath
. It promotes intrinsic tendon healing and decreases adhesion formation
. It minimizes tension on the A2 and A4 pulleys
. It allows the lumbricals to retract, reducing tension on the repair site

Correct Answer & Explanation

. It decreases the tensile strength of the repair, preventing stiffness

Explanation

Early mobilization after flexor tendon repair promotes intrinsic healing within the tendon itself and limits extrinsic healing or adhesions to surrounding tissues. This results in improved tendon gliding and better clinical range of motion without significantly compromising repair strength.

Question 11231

Topic: 1. General Principles & Basic Science
A 55-year-old female presents with bilateral base of thumb pain, positive grind tests, and radiographic evidence of severe trapeziometacarpal joint space narrowing, osteophytes, and subchondral sclerosis (Eaton-Littler Stage III). Conservative management has failed. What is the gold standard surgical treatment?
. Metacarpophalangeal joint fusion
. Trapezium osteotomy
. Ligament reconstruction and tendon interposition (LRTI)
. First dorsal compartment release
. EPL to EPB tendon transfer

Correct Answer & Explanation

. Ligament reconstruction and tendon interposition (LRTI)

Explanation

For advanced thumb CMC osteoarthritis (Eaton Stage III) failing conservative treatment, trapeziectomy with or without Ligament Reconstruction and Tendon Interposition (LRTI) is the standard surgical option.

Question 11232

Topic: 1. General Principles & Basic Science

A 30-year-old powerlifter feels a tearing sensation in his anterior chest while performing a heavy bench press. Examination reveals loss of the anterior axillary fold. When evaluating a pectoralis major rupture, where does the failure most commonly occur?

. Clavicular head at the muscle-tendon junction
. Sternal head at the humeral insertion
. Clavicular head at the clavicular origin
. Sternal head at the sternal origin
. Mid-belly of the sternal head

Correct Answer & Explanation

. Clavicular head at the muscle-tendon junction

Explanation

Pectoralis major ruptures almost exclusively occur in the sternal head, most commonly at its tendinous insertion on the lateral lip of the bicipital groove of the humerus.

Question 11233

Topic: 1. General Principles & Basic Science

A 19-year-old male rugby player sustains a direct blow to the medial clavicle, resulting in a posterior sternoclavicular dislocation. He complains of mild dysphagia but has normal vital signs. What is the most appropriate initial management step?

. Immediate open reduction in the emergency department
. Closed reduction in the operating room with a cardiothoracic surgeon on standby
. Figure-of-eight brace and observation
. Urgent CT angiogram followed by observation
. Excision of the medial clavicle

Correct Answer & Explanation

. Immediate open reduction in the emergency department

Explanation

Posterior sternoclavicular dislocations can compress critical mediastinal structures (trachea, esophagus, great vessels). Closed reduction should be attempted in the operating room under general anesthesia with a cardiothoracic surgeon available in case of catastrophic vascular injury during reduction.

Question 11234

Topic: 1. General Principles & Basic Science

A 58-year-old female with advanced base of thumb arthritis undergoes a ligament reconstruction and tendon interposition (LRTI) procedure using the flexor carpi radialis (FCR) tendon. Which primary stabilizing ligament of the first carpometacarpal joint is this procedure attempting to reconstruct?

. Dorsal radial ligament
. Posterior oblique ligament
. Anterior oblique (beak) ligament
. Intermetacarpal ligament
. Ulnar collateral ligament

Correct Answer & Explanation

. Dorsal radial ligament

Explanation

The LRTI procedure primarily aims to reconstruct the anterior oblique ligament (often called the beak ligament), which is the primary restraint to dorsal subluxation of the first carpometacarpal joint.

Question 11235

Topic: 1. General Principles & Basic Science

A 45-year-old obese male undergoes a complex T10-Pelvis posterior spinal fusion. Postoperatively, he complains of painless, profound bilateral vision loss. Examination reveals sluggish pupillary responses and optic disc swelling. Which of the following risk factors is most strongly associated with this complication?

. Use of a Wilson frame causing increased abdominal pressure
. Supine positioning for greater than 6 hours
. Intraoperative hypotensive anesthesia and prolonged prone positioning
. Use of tranexamic acid during surgery
. Hypervolemic fluid resuscitation

Correct Answer & Explanation

. Use of a Wilson frame causing increased abdominal pressure

Explanation

Postoperative visual loss (POVL), specifically ischemic optic neuropathy (ION), is associated with prolonged prone positioning, large intraoperative blood loss, and prolonged hypotension. These factors lead to decreased venous return and subsequent optic nerve ischemia.

Question 11236

Topic: Surgical Anatomy & Approaches

When performing a direct anterior approach to the hip for total hip arthroplasty, the internervous plane utilized is between the tensor fasciae latae (TFL) and the sartorius superficially. Which two nerves supply these muscles respectively?

. Superior gluteal nerve and femoral nerve
. Inferior gluteal nerve and obturator nerve
. Superior gluteal nerve and sciatic nerve
. Femoral nerve and obturator nerve
. Inferior gluteal nerve and femoral nerve

Correct Answer & Explanation

. Superior gluteal nerve and femoral nerve

Explanation

The direct anterior (Smith-Petersen) approach utilizes a true internervous and intermuscular plane. Superficially, the plane is between the Sartorius (supplied by the femoral nerve) and the Tensor Fasciae Latae (supplied by the superior gluteal nerve). Deep, the plane is between the Rectus Femoris (femoral nerve) and the Gluteus Medius (superior gluteal nerve).

Question 11237

Topic: Surgical Anatomy & Approaches

Which surgical approach to the hip is most frequently associated with the risk of iatrogenic injury to the superior gluteal nerve?

. Direct anterior approach (Smith-Petersen)
. Anterolateral approach (Watson-Jones)
. Direct lateral approach (Hardinge)
. Posterior approach (Moore)
. Medial approach (Ludloff)

Correct Answer & Explanation

. Direct anterior approach (Smith-Petersen)

Explanation

The direct lateral (Hardinge) approach involves splitting the gluteus medius and minimus muscles. The superior gluteal nerve innervates these muscles and runs approximately 3 to 5 cm proximal to the tip of the greater trochanter. Extending the split too proximally places the main trunk of the nerve at significant risk.

Question 11238

Topic: 1. General Principles & Basic Science

Tranexamic acid (TXA) is routinely utilized in total joint arthroplasty to minimize perioperative blood loss. What is the cellular mechanism of action of TXA?

. Activation of the extrinsic coagulation cascade
. Inhibition of cyclooxygenase-2 (COX-2)
. Competitive inhibition of plasminogen activation
. Cross-linking of fibrin monomers
. Direct vasoconstriction of capillary beds

Correct Answer & Explanation

. Activation of the extrinsic coagulation cascade

Explanation

Tranexamic acid (TXA) is a synthetic analog of the amino acid lysine. It functions as an antifibrinolytic by reversibly and competitively binding to the lysine receptor sites on plasminogen. This prevents plasminogen from being activated to plasmin, thereby inhibiting the degradation of fibrin clots.

Question 11239

Topic: Biomechanics & Biomaterials
The introduction of highly cross-linked polyethylene (HXLPE) has significantly reduced wear rates and osteolysis in THA. However, the cross-linking process alters the mechanical properties of the material. Which of the following properties is primarily DECREASED by the irradiation process?
. Ultimate tensile strength
. Wear resistance
. Hardness
. Oxidation potential
. Elastic modulus

Correct Answer & Explanation

. Ultimate tensile strength

Explanation

While the irradiation process used to create highly cross-linked polyethylene significantly improves its adhesive and abrasive wear resistance, it comes at a cost to its mechanical properties. Irradiation decreases ultimate tensile strength, yield strength, ductility, and fracture toughness, making the material more susceptible to fatigue fracture or rim failure.

Question 11240

Topic: Biomechanics & Biomaterials

In the manufacturing of highly cross-linked polyethylene (XLPE) for THA, irradiation is used to create cross-links that improve wear resistance. What is the primary biomechanical tradeoff of using a 'remelting' process compared to an 'annealing' process to eliminate free radicals?

. Remelting severely decreases oxidation resistance over time.
. Remelting increases the risk of early severe volumetric wear.
. Remelting causes a significant decrease in fatigue and yield strength.
. Remelting leads to an increased risk of third-body wear generation.
. Remelting fails to eliminate the majority of free radicals.

Correct Answer & Explanation

. Remelting severely decreases oxidation resistance over time.

Explanation

Irradiation creates free radicals that can cause oxidation. Heating the polyethylene eliminates these free radicals. Remelting (heating above the melting point) completely extinguishes free radicals but decreases the material's mechanical properties (fatigue and yield strength). Annealing (heating below the melting point) maintains mechanical strength but leaves residual free radicals, which require adding antioxidants like Vitamin E to prevent oxidation.

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