Menu

1. General Principles & Basic Science MCQs

Practice Set 485 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 9681

Topic: Biomechanics & Biomaterials

A patient experiences persistent, non-radicular low back pain 3 months after a successful lumbar microdiscectomy, with no evidence of recurrent herniation or instability on MRI. What is a common cause for this type of persistent pain?

. Piriformis syndrome
. Facet joint arthropathy
. Discitis
. Epidural fibrosis
. Chronic regional pain syndrome (CRPS)

Correct Answer & Explanation

. Facet joint arthropathy

Explanation

Persistent non-radicular low back pain after successful microdiscectomy, without evidence of recurrent herniation or instability, often points to alternative pain generators. Facet joint arthropathy, either pre-existing or exacerbated by altered biomechanics, is a common cause of such pain. Epidural fibrosis is more typically associated with recurrent radicular pain. Discitis would involve infectious signs like fever and elevated inflammatory markers. CRPS is a distinct neuropathic pain syndrome. Piriformis syndrome causes radicular pain.

Question 9682

Topic: 1. General Principles & Basic Science

Following a lumbar microdiscectomy, what is a typical recommendation regarding initial activity restriction?

. Immediate return to full activity
. Strict bed rest for 1 week
. Avoid bending, lifting, and twisting (BLT) for 4-6 weeks
. Swimming only for the first month
. Running is permitted after 2 weeks

Correct Answer & Explanation

. Avoid bending, lifting, and twisting (BLT) for 4-6 weeks

Explanation

After a lumbar microdiscectomy, patients are typically advised to avoid bending, lifting (heavy objects), and twisting (BLT) movements for 4-6 weeks to protect the healing annular defect and reduce the risk of recurrent herniation. Gradual return to activity and physical therapy are initiated. Immediate return to full activity, strict bed rest, and high-impact activities are generally contraindicated.

Question 9683

Topic: Surgical Anatomy & Approaches

A patient complains of leg pain. A positive Femoral Nerve Stretch Test (FNST) is performed, reproducing the patient's pain. This test is MOST sensitive for detecting compression of which nerve roots?

. L5 and S1
. S1 and S2
. L2 and L3
. L4 and L5
. C5 and C6

Correct Answer & Explanation

. L2 and L3

Explanation

The Femoral Nerve Stretch Test (FNST) involves extending the hip and flexing the knee with the patient prone, stretching the femoral nerve. This test is most sensitive for detecting compression of the L2, L3, and sometimes L4 nerve roots (femoral nerve distribution), typically associated with high lumbar disc herniations.

Question 9684

Topic: 1. General Principles & Basic Science

During a microdiscectomy, excessive or prolonged retraction of the nerve root is a concern. What type of nerve injury is MOST likely to result from this?

. Neurotmesis
. Axonotmesis
. Neurapraxia
. Wallerian degeneration
. Hyperalgesia

Correct Answer & Explanation

. Neurapraxia

Explanation

Excessive nerve root retraction typically causes neurapraxia, which is a transient block of nerve conduction without structural damage to the axon. This usually results in temporary motor and/or sensory deficits that often resolve completely. Axonotmesis involves axonal damage with intact connective tissue, and neurotmesis involves complete transaction of the nerve, both of which are more severe and less common with careful retraction. Wallerian degeneration follows axonal damage.

Question 9685

Topic: 1. General Principles & Basic Science

What is the primary content of the nucleus pulposus in a healthy lumbar intervertebral disc?

. Type I collagen
. Elastin fibers
. Proteoglycans and water
. Calcium salts
. Adipose tissue

Correct Answer & Explanation

. Proteoglycans and water

Explanation

The nucleus pulposus is primarily composed of proteoglycans (especially aggrecan) embedded in a meshwork of fine collagen fibrils, which allows it to hold a large amount of water. This high water content gives the disc its turgor and ability to withstand compressive loads. Type I collagen is dominant in the annulus fibrosus, not the nucleus.

Question 9686

Topic: Surgical Anatomy & Approaches

During a straight leg raise (SLR) test, radicular pain is reproduced at 40 degrees of hip flexion. If dorsiflexion of the ankle then exacerbates the pain, what is this maneuver indicative of?

. Hamstring tightness
. Hip joint pathology
. Increased neural tension of the sciatic nerve
. Lumbar facet joint syndrome
. Piriformis muscle spasm

Correct Answer & Explanation

. Increased neural tension of the sciatic nerve

Explanation

Reproduction of radicular pain during an SLR test, especially when exacerbated by ankle dorsiflexion (Bragard's sign), is a strong indicator of increased neural tension or compression of the sciatic nerve roots (L4, L5, S1, S2). This maneuver further stretches the nerve, intensifying symptoms in the presence of irritation or compression. Hamstring tightness would cause posterior thigh pain but not typically radicular pain exacerbated by dorsiflexion.

Question 9687

Topic: 1. General Principles & Basic Science

Which of the following describes a key difference between a disc protrusion and a disc extrusion?

. A protrusion has a completely detached fragment, while an extrusion does not.
. In a protrusion, the disc material is still contained by intact annular fibers, whereas in an extrusion, it is not.
. An extrusion has a broader base than its apex, while a protrusion has a narrower base.
. In an extrusion, the largest dimension of the herniated material is greater than the base in any plane, while in a protrusion, the base is broader than the herniated material itself.
. Protrusions are always symptomatic, while extrusions are usually asymptomatic.

Correct Answer & Explanation

. In an extrusion, the largest dimension of the herniated material is greater than the base in any plane, while in a protrusion, the base is broader than the herniated material itself.

Explanation

In a disc protrusion, the base of the disc material extending beyond the disc space is broader than any dimension of the herniated material itself. Conversely, in a disc extrusion, the greatest dimension of the herniated disc material is larger than the base (neck) connecting it to the parent disc. A sequestered disc is a type of extrusion where the fragment is completely detached. Both can be symptomatic or asymptomatic.

Question 9688

Topic: 1. General Principles & Basic Science

What is the typical timeframe for maximum improvement following a successful lumbar microdiscectomy, with regard to resolution of radicular pain and neurological deficits?

. Within the first week
. 1-3 months
. 3-6 months
. 6-12 months
. Greater than 12 months

Correct Answer & Explanation

. 3-6 months

Explanation

While some immediate pain relief can be experienced, maximum improvement in radicular pain and neurological deficits following a successful lumbar microdiscectomy typically occurs over 3-6 months. This timeframe allows for resolution of inflammation, nerve healing, and completion of rehabilitation. Some subtle improvements may continue beyond 6 months, but the majority are seen within this window.

Question 9689

Topic: 1. General Principles & Basic Science

According to Paley's principles of deformity correction, if an osteotomy is performed at the CORA (Center of Rotation of Angulation) and the hinge is also placed at the CORA, what is the geometric result?

. Complete angular realignment without translation
. Angular realignment with intended translation
. Incomplete angular correction with inadvertent translation
. Pure translation without angular correction
. Limb shortening with rotational malalignment

Correct Answer & Explanation

. Complete angular realignment without translation

Explanation

Paley's Rule 1 states that if the osteotomy and the hinge are both located at the CORA, angular correction occurs without translation. This perfectly restores the mechanical axis.

Question 9690

Topic: 1. General Principles & Basic Science

A patient undergoes a supramalleolar osteotomy for a distal tibial valgus deformity. The osteotomy is performed proximal to the CORA due to poor skin quality, but the hinge is placed at the CORA. What is the expected mechanical outcome?

. Correction of angulation accompanied by translation at the osteotomy site
. Correction of angulation without any translation
. Incomplete angular correction requiring secondary surgery
. Pure translation without angular correction
. Creation of a secondary multi-apical deformity

Correct Answer & Explanation

. Correction of angulation accompanied by translation at the osteotomy site

Explanation

Paley's Rule 2 states that if the hinge is at the CORA but the osteotomy is at a different level, the mechanical axis will be realigned, but translation will occur at the osteotomy site. This is often necessary when bone or soft tissue quality dictates a different osteotomy level.

Question 9691

Topic: 1. General Principles & Basic Science

A 14-year-old presents with symptomatic coxa valga, and a varus-producing proximal femoral osteotomy is planned. According to Paley's Rule 3, if both the osteotomy and the hinge are placed proximal to the CORA, what will be the result?

. The mechanical axis will be completely restored without offset
. A translation deformity will be created without angular correction
. A secondary translation deformity will be introduced, causing mechanical axis deviation
. An opening wedge correction will occur strictly at the CORA
. A closing wedge correction will occur strictly at the CORA

Correct Answer & Explanation

. A secondary translation deformity will be introduced, causing mechanical axis deviation

Explanation

Paley's Rule 3 dictates that if the osteotomy and hinge are placed at a level different from the CORA, the angular deformity is corrected, but a secondary translation deformity is created. This results in an iatrogenic mechanical axis deviation.

Question 9692

Topic: 1. General Principles & Basic Science

A subtrochanteric osteotomy is planned for a proximal femoral deformity. To strictly adhere to Paley's Rule 2 for optimal mechanical axis realignment, where should the hinge and osteotomy be placed relative to the CORA?

. Osteotomy at CORA, hinge at CORA
. Osteotomy away from CORA, hinge at CORA
. Osteotomy away from CORA, hinge away from CORA
. Osteotomy at CORA, hinge away from CORA
. Osteotomy and hinge both placed at the joint line

Correct Answer & Explanation

. Osteotomy away from CORA, hinge at CORA

Explanation

Paley's Rule 2 specifies placing the hinge exactly at the CORA while performing the osteotomy at a different level. This allows angular correction while automatically producing the translation necessary to realign the mechanical axis.

Question 9693

Topic: 1. General Principles & Basic Science

When performing a large closing wedge supramalleolar osteotomy for a severe valgus deformity of the distal tibia, what must generally be done to the fibula to prevent tethering?

. Leave the fibula entirely intact
. Perform an extra-articular arthrodesis of the distal tibiofibular joint
. Perform a transverse or oblique fibular osteotomy
. Resect the entire distal 5 cm of the fibula
. Fix the fibula rigidly to the tibia prior to any correction

Correct Answer & Explanation

. Perform a transverse or oblique fibular osteotomy

Explanation

The intact fibula acts as a rigid strut that restricts tibial angular correction. An oblique or transverse fibular osteotomy must be performed to allow the distal tibial block to rotate freely into its corrected position.

Question 9694

Topic: 1. General Principles & Basic Science

The Center of Rotation of Angulation (CORA) of a deformed long bone is defined anatomically as the exact point where:

. The mechanical axes of the adjacent normal joints intersect
. The proximal and distal anatomical axes of the deformed bone segments intersect
. The mechanical axis of the proximal segment intersects the joint line
. The center of the planned osteotomy gap is located
. The soft tissue tension is at its maximum point

Correct Answer & Explanation

. The proximal and distal anatomical axes of the deformed bone segments intersect

Explanation

The CORA is mathematically defined as the intersection point of the proximal and distal bone axes (either anatomical or mechanical). It dictates the magnitude, direction, and apex of the angular deformity.

Question 9695

Topic: 1. General Principles & Basic Science

According to Paley's osteotomy rules, if an osteotomy is performed at the center of rotation of angulation (CORA) and the correction hinge is also placed exactly at the CORA, what is the geometric outcome of the correction?

. Pure angulation with collinear realignment of the mechanical axes
. Angulation combined with collinear translation of the mechanical axes
. Pure translation without angulation
. Angulation with a newly introduced translation deformity
. Collinear realignment of the anatomical axes with paradox mechanical translation

Correct Answer & Explanation

. Pure angulation with collinear realignment of the mechanical axes

Explanation

Paley's Osteotomy Rule 1 states that when both the osteotomy and the hinge are placed at the CORA, the result is pure angulation. The mechanical axes will align perfectly without any translation.

Question 9696

Topic: 1. General Principles & Basic Science

A 45-year-old patient presents with a severe distal tibial deformity. Preoperative planning determines that the osteotomy must be performed proximal to the CORA due to poor soft tissue envelope, but the external fixator hinge is placed exactly at the CORA. Based on Paley's Rule 2, what will be the resulting correction?

. Pure angulation with no translation at the osteotomy site
. Angulation with collinear realignment, resulting in translation at the osteotomy site
. Angulation with a secondary translation deformity causing non-collinear axes
. Pure translation at the osteotomy site with no angular correction
. Loss of bone length without angular or translational correction

Correct Answer & Explanation

. Angulation with collinear realignment, resulting in translation at the osteotomy site

Explanation

Paley's Osteotomy Rule 2 states that if the hinge is at the CORA but the osteotomy is at a different level, the mechanical axes will realign collinearly. However, the bone ends at the osteotomy site will translate relative to each other.

Question 9697

Topic: 1. General Principles & Basic Science

A patient is undergoing a focal dome osteotomy for a tibial deformity. The surgeon plans to correct the deformity without inducing any translation at the osteotomy site. Where must the center of the focal dome cut be placed to achieve this?

. Exactly at the CORA
. At the transverse bisector line, 2 cm proximal to the CORA
. At the level of the desired lengthening
. At the anatomical axis of the distal fragment
. On the convex side of the mechanical axis deviation

Correct Answer & Explanation

. Exactly at the CORA

Explanation

A focal dome osteotomy allows angular correction by rotating the fragments around the center of the dome. If the center of the dome perfectly coincides with the CORA, angular correction occurs without translation, adhering to Paley's Rule 1.

Question 9698

Topic: 1. General Principles & Basic Science

A patient with a complex multi-apical tibial deformity is evaluated. When drawing the mechanical axis lines of the proximal and distal fragments, they do not intersect at a single CORA but remain parallel or intersect far outside the bone. This indicates which of the following?

. A pure uniapical angular deformity
. A purely rotational deformity
. A translation deformity or multi-apical deformity
. A purely length-discrepancy deformity
. An isolated intra-articular step-off

Correct Answer & Explanation

. A translation deformity or multi-apical deformity

Explanation

When the proximal and distal mechanical axes are parallel and do not intersect, it indicates a pure translation deformity. If they intersect at multiple points when intermediate segments are analyzed, it confirms a multi-apical deformity.

Question 9699

Topic: 1. General Principles & Basic Science

According to Paley's Rule 3, what occurs when the osteotomy and the correction hinge are both placed at a level different from the CORA?

. Pure angulation with perfectly collinear mechanical axes
. Angulation combined with a secondary translation deformity
. Pure translation without any change in angulation
. Collinear realignment with no cortical gap
. Spontaneous correction of limb length discrepancy

Correct Answer & Explanation

. Angulation combined with a secondary translation deformity

Explanation

Rule 3 dictates that if the hinge and osteotomy are both away from the CORA, the resulting correction will produce angulation but the mechanical axes will not be collinear, effectively creating a new translation deformity.

Question 9700

Topic: Physiology & Rehabilitation

A pelvic support osteotomy (Ilizarov hip reconstruction) is planned for a young adult with a chronically dislocated, painful hip. The first osteotomy of this procedure is typically performed in the proximal femur. What specific geometric changes are created at this proximal osteotomy site?

. Varus and flexion
. Varus and internal rotation
. Valgus and extension
. Valgus and internal rotation
. Pure external rotation

Correct Answer & Explanation

. Valgus and extension

Explanation

The proximal osteotomy in a pelvic support reconstruction is designed to create valgus and extension. The valgus eliminates Trendelenburg gait by abutting the pelvis, and the extension compensates for the fixed flexion contracture of the chronically dislocated hip.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page