Meniscal Tears: Anatomy, Bucket Handle Tears, Vascular Zones & Rehab MCQs

Meniscal Injuries of the Knee

The menisci are fibrocartilaginous wedges that act as shock absorbers, load transmitters, and stabilizers of the knee. Injuries here are the most common cause of knee surgery.

1. Anatomy & Differences

• Medial Meniscus: C-shaped. It is firmly attached to the deep Medial Collateral Ligament (MCL) and capsule. Because it is relatively immobile, it is torn 20 times more often than the lateral.
• Lateral Meniscus: O-shaped (Circular). It is not attached to the LCL (separated by Popliteus tendon). It is mobile, allowing it to slide away from injury forces.

2. Vascular Zones (Critical for Prognosis)

Healing depends entirely on blood supply (from genicular arteries):

• Red-Red Zone (Outer 1/3): Excellent blood supply. Tears here can heal spontaneously or with suture repair.
• Red-White Zone (Middle 1/3): Variable healing.
• White-White Zone (Inner 1/3): Avascular (No blood). Tears here do not heal and require excision (Meniscectomy).

3. Types of Tears & Mechanism

• Mechanism: Twisting force on a semi-flexed, weight-bearing knee (Football, Squatting).
• Longitudinal / Bucket Handle: The inner rim detaches and flips into the intercondylar notch. Causes Locking (Inability to extend knee).
• Radial / Parrot Beak: Common in lateral meniscus.
• Horizontal (Cleavage): Degenerative type, common in elderly.

4. Clinical Features & Tests

• Joint Line Tenderness: Most specific sign.
• McMurray’s Test: Flexion + Rotation + Extension. Palpable/Audible click = Positive.
• Apley’s Grinding: Patient prone, compression + rotation.
• Thessaly Test: Standing on one leg and twisting (High sensitivity).

5. Management

• Meniscectomy (Partial): Removal of the torn white zone fragment. Allows immediate weight bearing but increases long-term OA risk.
• Meniscal Repair: Suturing the red zone tear. Requires restricted weight bearing/flexion for 4-6 weeks to allow healing.

25 Practice MCQs

Q1. The most common meniscus to be injured is:

Answer: A). Because it is less mobile and tethered to the MCL.

Q2. The "White-White" zone of the meniscus:

Answer: B). Tears here require partial meniscectomy.

Q3. Which tear causes "Locking" of the knee?

Answer: A). The fragment mechanically blocks extension.

Q4. Apley's Grinding Test distinguishes meniscal injury from:

Answer: A). Compression hurts meniscus; Distraction hurts ligaments.

Q5. Joint line tenderness is:

Answer: A). Palpation directly over the torn cartilage.

Q6. Discoid Meniscus is:

Answer: A). The meniscus is disc-shaped instead of O-shaped.

Q7. What separates the Lateral Meniscus from the LCL?

Answer: A). This gap makes the lateral meniscus more mobile.

Q8. Meniscal Repair is indicated for:

Answer: A). Requires blood supply for healing.

Q9. The primary function of the meniscus is:

Answer: A). Protects the articular cartilage.

Q10. McMurray's test for Medial Meniscus involves:

Answer: A). External rotation stresses the medial meniscus.

Q11. Total Meniscectomy leads to:

Answer: A). Contact stress on cartilage increases by 300%.

Q12. Meniscal cysts are most often associated with:

Answer: B). Synovial fluid pumps through the tear into a cyst.

Q13. "Giving way" sensation suggests:

Answer: A). Common in meniscus and ACL injuries.

Q14. Thessaly test is performed at:

Answer: A). Reproduces physiological loading.

Q15. The O'Donoghue Triad usually involves the:

Answer: B). Although recent studies show Lateral Meniscus is more common in acute ACL tears.

Q16. Effusion in meniscal tears typically appears:

Answer: A). Immediate swelling (Hemarthrosis) suggests ACL tear or fracture.

Q17. MRI signal grading for meniscus: Grade 3 indicates:

Answer: A). Grades 1 and 2 are degeneration, not tears.

Q18. Bounce Home Test is positive if:

Answer: A). Indicates a mechanical block (meniscus fragment or loose body).

Q19. Post-Meniscectomy rehab allows:

Answer: A). Recovery is fast (3-4 weeks) compared to repair.

Q20. Meniscal Root Avulsion acts like:

Answer: A). Must be repaired to prevent rapid arthritis.

Q21. The medial meniscus covers approximately:

Answer: A). Lateral covers more (70-80%).

Q22. What happens to the meniscus in an ACL deficient knee?

Answer: A). The medial meniscus becomes the primary stabilizer (brake-stop effect).

Q23. Inside-Out, Outside-In, and All-Inside are techniques for:

Answer: A). Different ways to place stitches arthroscopically.

Q24. Deep squats are often avoided in rehab because:

Answer: A). The posterior horn is the most common tear site.

Q25. Ramp Lesion refers to:

Answer: A). Hidden lesion often missed on MRI, common with ACL tears.