Must-Know MCQs for the Fellowship Exam

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Courtesy: Zaid Al-RUb, FRCS Orth, Founder, OrthoPass

 

Courtesy: Zaid Al-Rub, Founder and CEO, OrthoPass

1. Gap Balancing in Total Knee Replacement

Scenario

• Primary Total Knee Replacement (TKR).
• After distal femur and proximal tibial cuts:
  • Extension gap – tight
  • Flexion gap – balanced

First Step

Posterior capsule release

Principles of Gap Balancing

• Rule 1: Address soft tissue before additional bone resection.
• Rule 2:
  • Distal femur cut ? affects extension gap
• Rule 3:
  • Posterior femoral condyles ? affect flexion gap
• Rule 4:
  • Proximal tibia ? affects both flexion and extension

Practical Approach

• Tight in extension only:
  • Posterior capsule release
  • If unresolved ? resect more distal femur

Ideal Gap Shape

• Balanced knee ? rectangular flexion and extension gaps

Unbalanced Knee

• Trapezoidal gap
• Often occurs in varus knees with tight medial structures

2. Total Knee Replacement in Valgus Deformity

Epidemiology

• Valgus knees represent ~10% of TKR cases

Pathology

• Medial Collateral Ligament (MCL) ? stretched or incompetent
• Lateral structures ? contracted

Surgical Goal

Release tight lateral structures to restore balance.

Important Surgical Principles

• Perform releases with knee in extension
• Check balance after each release
• Perform minimal necessary releases

Structures Often Released

Common sequence (varies between surgeons):

1. Osteophytes
2. Lateral capsule
3. Iliotibial band
4. Popliteus tendon
5. Lateral collateral ligament (last resort)

Correct MCQ Concept

• Valgus deformity >15° often requires release of:
  • Iliotibial band
  • Popliteus tendon

Complication

• Risk of common peroneal nerve traction injury

3. Total Hip Replacement vs Hemiarthroplasty in Neck of Femur Fracture

Total Hip Replacement (THR)

Advantages

• Better:
  • Function
  • Quality of life
  • Patient satisfaction

Disadvantages

• Longer surgery
• Higher dislocation rate
• Higher revision rate in some observational studies

Hemiarthroplasty

Advantages

• Shorter surgery
• Lower dislocation risk

Disadvantages

• Acetabular cartilage wear
• Worse functional outcome

Key MCQ Point

Compared with hemiarthroplasty, THR shows:

Higher revision rate

4. Safe Zone for Acetabular Screw Placement

During Total Hip Replacement, acetabular screws should be placed in the:

Posterosuperior quadrant

Acetabular Quadrants

Defined by two lines from the center of the acetabulum to:

• Anterior Superior Iliac Spine (ASIS)
• Posterior Superior Iliac Spine (PSIS)

Safe Zone

• Posterosuperior quadrant

Reason

Avoids injury to:

• External iliac vessels
• Obturator vessels
• Sciatic nerve

5. Erb’s Palsy (Obstetric Brachial Plexus Injury)

Nerve Roots

• C5–C6

Typical Limb Position (Waiter’s Tip)

• Shoulder adduction
• Shoulder internal rotation
• Elbow extension
• Forearm pronation
• Wrist flexion

Muscles Affected

• Deltoid
• Supraspinatus
• Infraspinatus
• Biceps

Characteristic Complication

• Posterior shoulder dislocation or subluxation

MCQ Key Point

Anterior shoulder dislocation is NOT typical

6. Developmental Dysplasia of the Hip (DDH)

Age in Question

6 months

Most Sensitive Clinical Sign

Limited hip abduction in flexion

Test Usefulness by Age

Test	Age group
Ortolani test	Neonates
Barlow test	Neonates
Galeazzi test	Later infancy
Limited abduction	>3–6 months

Asymmetric Skin Folds

• Low diagnostic value
• High false positive rate

7. Indications for Surgery in Thoracolumbar Burst Fracture

Common criteria for surgery include:

• Kyphosis >30°
• Vertebral body height loss >50%
• Canal compromise >50%
• Progressive neurological deficit

Important MCQ Concept

• Canal compromise alone is NOT an indication

Definition of Burst Fracture

• Failure of:
  • Anterior column
  • Posterior vertebral body cortex
• With retropulsion of fragments

8. Adolescent Idiopathic Scoliosis Management

Case Parameters

• Age: 12 years
• Cobb angle: 30°
• Risser grade: 2

Management

Brace treatment

General Treatment Guidelines

Cobb Angle	Management
<20°	Observation
20–40°	Bracing
>45°	Surgery

Risser Grade Meaning

• Indicates skeletal maturity
• 0–1 ? rapid growth phase
• 4–5 ? skeletal maturity

9. Structure of Articular Cartilage

Layers of cartilage:

1. Superficial zone
2. Middle zone
3. Deep zone
4. Tidemark
5. Calcified cartilage

Proteoglycan Distribution

• Highest concentration ? Deep zone

Collagen Orientation

Layer	Fibre orientation
Superficial	Parallel
Middle	Oblique
Deep	Perpendicular

Function

• Superficial ? shear resistance
• Deep ? compressive load resistance

10. Principles of Plate Fixation

Correct Principle

Maximum plate efficiency occurs when applied to the tension side of the bone

Additional Biomechanics Facts

Pullout strength depends on:

• Thread diameter

Plate bending rigidity:

• Proportional to thickness³

Material properties

• Stainless steel modulus > titanium

Application

• Tension band principle in fracture fixation

Major References Verified

• Campbell’s Operative Orthopaedics
• Rockwood and Green’s Fractures in Adults
• Lovell and Winter’s Pediatric Orthopaedics