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1. General Principles & Basic Science MCQs

Practice Set 634 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 12661

Topic: 1. General Principles & Basic Science

What is the primary characteristic of a meniscal 'bucket-handle' tear?

. A radial tear extending from the inner edge to the periphery.
. A horizontal tear separating the meniscus into superior and inferior halves.
. A longitudinal tear with a displaced central fragment.
. A complex degenerative tear involving multiple planes.
. A flap tear that is non-displaced.

Correct Answer & Explanation

. A longitudinal tear with a displaced central fragment.

Explanation

A bucket-handle tear is a specific type of longitudinal meniscal tear where the inner portion of the meniscus is detached and displaced into the intercondylar notch, resembling the handle of a bucket. This displaced fragment often causes mechanical symptoms such as locking and can lead to significant pain and dysfunction.

Question 12662

Topic: 1. General Principles & Basic Science

The primary mechanism by which the meniscus acts as a shock absorber is through:

. Direct compression of its cellular components.
. Its ability to deform and distribute impact forces over a larger area.
. Release of lubricating synovial fluid.
. Electrical signaling via its nerve endings.
. Its inherent stiffness, preventing joint collapse.

Correct Answer & Explanation

. Its ability to deform and distribute impact forces over a larger area.

Explanation

The meniscus acts as a shock absorber by deforming under axial load, effectively increasing the contact area between the femoral and tibial condyles and converting axial loads into circumferential 'hoop' stresses. This distribution of force over a wider area significantly reduces peak contact stresses on the articular cartilage, thereby dissipating energy and protecting the chondral surfaces from damaging impact forces.

Question 12663

Topic: 1. General Principles & Basic Science

Meniscal allograft transplantation (MAT) aims to restore which of the following functions most effectively?

. Native meniscal vascularity.
. Proprioception and neural feedback.
. Biomechanics of load transmission and contact pressure reduction.
. Ligamentous stability of the knee.
. Full range of motion in a chronically stiff knee.

Correct Answer & Explanation

. Biomechanics of load transmission and contact pressure reduction.

Explanation

Meniscal allograft transplantation (MAT) is primarily performed to restore the biomechanical functions of the meniscus, specifically load transmission, contact pressure reduction, and shock absorption. The goal is to prevent or slow the progression of tibiofemoral osteoarthritis in patients who have undergone total meniscectomy and are experiencing symptoms. While some revascularization and cellular infiltration may occur, full restoration of native vascularity and innervation (proprioception) is generally not achieved or is minimal.

Question 12664

Topic: 1. General Principles & Basic Science

The specific orientation of collagen fibers in the meniscus helps convert what type of force into what other type of force?

. Shear force into tensile force.
. Tensile force into compressive force.
. Rotational force into shear force.
. Compressive force into hoop (circumferential) stress.
. Axial force into bending moment.

Correct Answer & Explanation

. Compressive force into hoop (circumferential) stress.

Explanation

The circumferential orientation of the vast majority of type I collagen fibers is perfectly adapted to convert vertical, axial compressive loads on the knee into tensile 'hoop stresses' within the meniscal body. These hoop stresses are then resisted by the strong circumferential fibers, allowing the meniscus to effectively transmit and distribute load.

Question 12665

Topic: 1. General Principles & Basic Science

The meniscal periphery receives innervation primarily from branches of which nerve?

. Femoral nerve.
. Obturator nerve.
. Saphenous nerve.
. Tibial nerve.
. Peroneal nerve.

Correct Answer & Explanation

. Tibial nerve.

Explanation

The menisci, particularly their vascularized periphery, are innervated by branches of the tibial nerve. These nerve endings contribute to both proprioception (sensing joint position and movement) and nociception (pain sensation), playing a role in knee joint homeostasis and injury response.

Question 12666

Topic: 1. General Principles & Basic Science

Which tear pattern is considered to have the highest risk of meniscal extrusion and poor biomechanical function, even if the primary tear itself is small?

. Horizontal cleavage tear.
. Anterior horn avulsion.
. Posterior horn root tear.
. Peripheral longitudinal tear.
. Flap tear.

Correct Answer & Explanation

. Posterior horn root tear.

Explanation

A posterior horn root tear (avulsion) is particularly devastating to meniscal function. Even if the tear involves a relatively small area, by severing the meniscal anchor, it disrupts the entire 'hoop stress' mechanism of the meniscus. This leads to meniscal extrusion, rendering the meniscus functionally incompetent and causing a significant increase in tibiofemoral contact pressures, similar to a complete meniscectomy.

Question 12667

Topic: Physiology & Rehabilitation

The presence of sensory nerve endings (mechanoreceptors and nociceptors) in the menisci suggests their role in:

. Joint lubrication and nutrient transport.
. Shock absorption and load distribution.
. Proprioception and pain perception.
. Immunological response to joint injury.
. Regulation of synovial fluid production.

Correct Answer & Explanation

. Proprioception and pain perception.

Explanation

The menisci are innervated, particularly in their peripheral vascularized zones and horn attachments, by both mechanoreceptors (e.g., Ruffini endings, Pacinian corpuscles, Golgi tendon organ-like endings) and free nerve endings (nociceptors). This innervation indicates their crucial role in providing proprioceptive feedback (sense of joint position and movement) to the central nervous system and in mediating pain perception.

Question 12668

Topic: 1. General Principles & Basic Science

In a horizontal cleavage tear of the meniscus, what is the typical tissue response at the interface of the tear?

. Rapid revascularization and fibrous union.
. Formation of a pseudoarthrosis-like fibrous tissue.
. Complete regeneration of hyaline cartilage.
. Progressive degradation and widening of the tear.
. Calcium deposition and ossification.

Correct Answer & Explanation

. Progressive degradation and widening of the tear.

Explanation

Horizontal cleavage tears, especially those extending into the avascular white-white zone, often show limited healing potential. Due to the lack of blood supply and the mechanical shearing forces, the tear interface tends to undergo progressive degradation and widening, forming an intrameniscal cyst or leading to further delamination, rather than healing with robust fibrous tissue.

Question 12669

Topic: 1. General Principles & Basic Science
Which type of collagen is found in small amounts in the meniscus, particularly near the articular surfaces, reflecting a more chondral phenotype in certain regions?
. Type I.
. Type III.
. Type X.
. Type IX.
. Type II.

Correct Answer & Explanation

. Type II.

Explanation

While the meniscus is predominantly type I collagen, small amounts of type II collagen are found, particularly in the regions closer to the articular cartilage surfaces. This reflects the fibrocartilaginous nature of the meniscus, which shares some characteristics with hyaline cartilage, especially in its inner avascular portion.

Question 12670

Topic: 1. General Principles & Basic Science

The menisci contribute to knee joint stability primarily as:

. Primary active muscle stabilizers.
. Static primary ligamentous restraints.
. Secondary static and dynamic stabilizers.
. Lubricant reservoirs.
. Direct energy producers for motion.

Correct Answer & Explanation

. Secondary static and dynamic stabilizers.

Explanation

The menisci are considered secondary stabilizers of the knee joint. They contribute both statically, by their wedge shape and attachments enhancing joint congruity, and dynamically, by their movement and load-bearing function, particularly in conjunction with ligaments like the ACL. They are not primary ligamentous restraints or active muscle stabilizers.

Question 12671

Topic: 1. General Principles & Basic Science

Which of the following describes the mobility of the lateral meniscus during knee motion?

. Relatively immobile due to strong capsular attachments.
. Moves minimally, primarily with femoral translation.
. More mobile than the medial meniscus, especially in flexion.
. Restricted by its strong attachment to the LCL.
. Does not move relative to the tibia.

Correct Answer & Explanation

. More mobile than the medial meniscus, especially in flexion.

Explanation

The lateral meniscus is significantly more mobile than the medial meniscus. Its attachments to the capsule are less extensive, and it has no direct attachment to the LCL (unlike the medial meniscus and MCL). This increased mobility, particularly during knee flexion and rotation, allows it to adapt to the changing curvature of the lateral femoral condyle and accommodate the pivot of the knee, sliding posteriorly in flexion and anteriorly in extension.

Question 12672

Topic: 1. General Principles & Basic Science

Which molecule is primarily responsible for the negative charge within the meniscal extracellular matrix, contributing to its osmotic swelling pressure and resistance to compression?

. Hyaluronic acid.
. Glycoproteins.
. Collagen fibrils.
. Keratan sulfate side chains of aggrecan.
. Elastin fibers.

Correct Answer & Explanation

. Keratan sulfate side chains of aggrecan.

Explanation

The negative charge within the meniscal extracellular matrix is primarily due to the highly sulfated glycosaminoglycan (GAG) side chains, such as chondroitin sulfate and keratan sulfate, attached to core proteins like aggrecan. These negative charges repel each other and attract water, creating a swelling pressure that resists compressive loads and contributes to the tissue's turgor and stiffness.

Question 12673

Topic: 1. General Principles & Basic Science

Which of the following statements about meniscal repair compared to meniscectomy is biomechanically correct?

. Meniscectomy fully restores joint congruity and load distribution.
. Meniscal repair, if successful, can restore the hoop stress mechanism and reduce contact pressures.
. Meniscal repair is always superior in pain relief, regardless of tear type or location.
. Meniscectomy leads to higher joint stability in ACL-deficient knees.
. Meniscal repair outcomes are identical to those of a never-injured meniscus.

Correct Answer & Explanation

. Meniscal repair, if successful, can restore the hoop stress mechanism and reduce contact pressures.

Explanation

Successful meniscal repair, by restoring the anatomical integrity of the meniscus, allows the re-establishment of the crucial hoop stress mechanism. This helps to redistribute loads over a larger contact area, reduce peak contact pressures on the articular cartilage, and thus protect the joint from accelerated degeneration, which is the primary biomechanical advantage over meniscectomy.

Question 12674

Topic: 1. General Principles & Basic Science

What is the key difference in histological composition that distinguishes fibrocartilage (like meniscus) from hyaline cartilage?

. Fibrocartilage has no chondrocytes.
. Hyaline cartilage is predominantly Type I collagen, while fibrocartilage is Type II.
. Fibrocartilage contains abundant Type I collagen, while hyaline cartilage is rich in Type II collagen.
. Fibrocartilage is highly vascularized, unlike hyaline cartilage.
. Hyaline cartilage lacks proteoglycans, whereas fibrocartilage has them.

Correct Answer & Explanation

. Fibrocartilage contains abundant Type I collagen, while hyaline cartilage is rich in Type II collagen.

Explanation

The key histological difference is the predominant collagen type. Fibrocartilage, such as the meniscus, is characterized by a high proportion of Type I collagen (90-95%), giving it strong tensile properties. Hyaline cartilage, found on articular surfaces, is characterized by a high proportion of Type II collagen, providing resistance to compression and a smooth gliding surface.

Question 12675

Topic: 1. General Principles & Basic Science

During the repair of a complete Zone II laceration of the flexor digitorum profundus (FDP), which biomechanical construct provides the optimal tensile strength to allow for a safe early active motion rehabilitation protocol while minimizing gap formation?

. A 2-strand core suture using braided non-absorbable material without an epitendinous repair
. A 4-strand core suture combined with a running epitendinous suture
. A 6-strand core suture utilizing isolated figure-of-eight throws
. A simple running epitendinous suture followed by prolonged immobilization
. A 2-strand Kessler core suture using monofilament absorbable material

Correct Answer & Explanation

. A 4-strand core suture combined with a running epitendinous suture

Explanation

Modern principles of Zone II flexor tendon repair emphasize that at least a 4-strand core suture, when combined with an epitendinous running suture, provides sufficient tensile strength and gap resistance to safely endure the stresses of an early active motion protocol. The epitendinous suture increases the repair strength by 10% to 50% and improves tendon gliding.

Question 12676

Topic: 1. General Principles & Basic Science
According to the Eaton-Littler classification of thumb carpometacarpal (CMC) joint osteoarthritis, which radiographic finding specifically differentiates Stage III from Stage II disease?
. Narrowing of the scaphotrapezial (ST) joint
. Presence of osteophytes measuring less than 2 mm
. Presence of osteophytes measuring greater than 2 mm with significant joint space narrowing
. Widening of the trapeziometacarpal joint space due to effusion
. Complete ankylosis of the trapeziometacarpal joint

Correct Answer & Explanation

. Presence of osteophytes measuring greater than 2 mm with significant joint space narrowing

Explanation

In the Eaton-Littler classification: Stage I has a normal contour but possible joint widening. Stage II shows mild joint space narrowing and osteophytes < 2 mm. Stage III is characterized by significant joint space narrowing, subchondral sclerosis, and osteophytes > 2 mm. Stage IV involves the addition of scaphotrapezial (ST) joint arthritis.

Question 12677

Topic: 1. General Principles & Basic Science

A 62-year-old female presents with a small, tense, translucent bump over the dorsum of her right index DIP joint. There is a longitudinal groove present in the adjacent fingernail. Which underlying articular pathology is universally associated with this soft tissue mass?

. Rheumatoid arthritis
. Psoriatic arthritis
. Osteoarthritis with associated osteophyte formation
. Gouty arthropathy
. Pyogenic arthritis

Correct Answer & Explanation

. Osteoarthritis with associated osteophyte formation

Explanation

The lesion described is a mucous cyst, which is a type of ganglion cyst that arises from the distal interphalangeal (DIP) joint. It is virtually always associated with underlying osteoarthritis of the DIP joint and the presence of dorsal osteophytes (Heberden's nodes). Successful surgical treatment requires excision of the cyst stalk and debridement of the underlying osteophyte.

Question 12678

Topic: 1. General Principles & Basic Science

A 45-year-old female complains of severe, exquisitely localized pain in the nail bed of her index finger, which worsens dramatically with cold exposure. Examination reveals a subtle bluish discoloration under the nail plate. Which of the following triad of signs is pathognomonic for this condition?

. Pain, cold sensitivity, and positive Tinel's sign
. Pain, cold sensitivity, and localized tenderness (Love's pin test)
. Cold sensitivity, nail ridging, and positive transillumination
. Localized tenderness, positive Hildreth's test, and positive Allen's test
. Night pain, cold sensitivity, and focal bone erosion

Correct Answer & Explanation

. Pain, cold sensitivity, and localized tenderness (Love's pin test)

Explanation

The classic triad for a glomus tumor includes severe localized pain, exquisite point tenderness (positive Love's test with a paperclip or pin), and cold sensitivity. Hildreth's test (relief of pain with a proximal tourniquet) is also highly specific for a glomus tumor.

Question 12679

Topic: 1. General Principles & Basic Science
According to the Eaton-Littler classification for basal joint (thumb CMC) arthritis, what characterizes Stage III disease?
. Slight joint space widening with normal articular contours
. Joint space narrowing with osteophytes less than 2mm
. Significant joint space narrowing with osteophytes greater than 2mm and subchondral sclerosis
. Pantrapezial arthritis involving the scaphotrapezial joint
. Complete ankylosis of the trapeziometacarpal joint

Correct Answer & Explanation

. Significant joint space narrowing with osteophytes greater than 2mm and subchondral sclerosis

Explanation

Eaton-Littler classification of thumb CMC arthritis: Stage I: widened joint space (synovitis). Stage II: mild joint space narrowing, osteophytes <2mm. Stage III: marked joint space narrowing, sclerosis, and osteophytes >2mm. Stage IV: pantrapezial arthritis (involvement of the STT joint in addition to the CMC joint).

Question 12680

Topic: 1. General Principles & Basic Science

A 60-year-old woman with long-standing rheumatoid arthritis presents with a sudden inability to actively extend her small and ring fingers at the metacarpophalangeal (MCP) joints. Over the next two weeks, the inability to extend the fingers progresses to involve the middle finger. Which of the following is the most likely underlying mechanism for this condition?

. Synovial infiltration and spontaneous rupture of the extensor hood
. Subluxation of the extensor tendons into the ulnar gutters
. Attrition of the tendons over a prominent, dorsally subluxated distal ulna
. Ischemic necrosis of the extensor muscle bellies
. Entrapment of the posterior interosseous nerve at the arcade of Frohse

Correct Answer & Explanation

. Attrition of the tendons over a prominent, dorsally subluxated distal ulna

Explanation

This presentation is classic for Vaughan-Jackson syndrome, which is characterized by a sequential rupture of the extensor tendons in rheumatoid arthritis patients, typically progressing from ulnar to radial. It is caused by mechanical attrition of the tendons rubbing against a prominent, dorsally subluxated distal ulna (caput ulnae) combined with chronic tenosynovitis.

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