Hand Tendon Injuries: Flexor vs Extensor Zones & Rehab Protocols

Tendon Injuries of the Hand

Managing tendon injuries is a delicate balance between protecting the repair and preventing adhesions. Understanding the anatomy of "Zones" is critical for prognosis.

[Image of Flexor Tendon Zones of Hand]

1. Flexor Tendons (Zones of Verdan)

• Zone I: Distal to FDS insertion (Only FDP injured). "Jersey Finger".
• Zone II ("No Man's Land"): From distal palmar crease to FDS insertion. Both FDS and FDP run in a tight fibro-osseous sheath. Poorest prognosis due to adhesion formation.
• Zone III: Lumbrical origin (Palm). Good prognosis.
• Zone IV: Carpal Tunnel. Risk of median nerve injury.
• Zone V: Forearm.

2. Extensor Tendons

• Zone I: DIP Joint. Injury = Mallet Finger.
• Zone III: PIP Joint. Injury = Boutonniere Deformity.
• Zone V: MCP Joint. "Fight Bite" injuries common here.

3. Physiotherapy Protocols

Golden Rule: Early controlled motion is better than immobilization for tendon healing.
Kleinert Protocol: Active Extension, Passive Flexion (using rubber bands).
Duran Protocol: Passive Flexion and Passive Extension.

25 Practice MCQs

Q1. "No Man's Land" refers to Flexor Zone:

Answer: B). Historically, repairs here always failed due to adhesions.

Q2. Which tendon flexes the DIP joint?

Answer: B). FDS stops at the middle phalanx.

Q3. Kleinert Protocol involves:

Answer: A). Allows the tendon to glide without tension on the repair.

Q4. Mallet finger is an injury to Extensor Zone:

Answer: A). Rupture of terminal extensor tendon.

Q5. In Zone II, the FDS tendon splits (Camper's Chiasm) to allow:

Answer: A). FDP runs deep to FDS proximally, then becomes superficial distally.

Q6. The vincula provide:

Answer: A). Vincula Brevia and Longa.

Q7. Boutonniere Deformity (Zone III extensor injury) consists of:

Answer: A). Central slip rupture causes lateral bands to subluxate volarly.

Q8. Which pulley is most critical to prevent "Bowstringing"?

Answer: A). Located over the proximal and middle phalanges respectively.

Q9. Weakest phase of tendon healing (highest rupture risk) is:

Answer: B). The tendon softens before collagen matures.

Q10. "Jersey Finger" is usually an avulsion of:

Answer: A). Ring finger is weakest; occurs during forced extension while grabbing.

Q11. Dorsal Blocking Splint for flexor repairs keeps the wrist in:

Answer: A). To relieve tension on the flexor tendon repair.

Q12. Tenolysis (surgery to release adhesions) is considered if no progress by:

Answer: A). Once passive ROM exceeds active ROM significantly.

Q13. Extensor tendons in Zone 5-7 are prone to adhesions with the:

Answer: A). They run in 6 compartments under the retinaculum.

Q14. FDS Test involves:

Answer: A). This neutralizes the FDP.

Q15. Swan Neck Deformity is:

Answer: A). Opposite of Boutonniere. Often due to Volar Plate laxity or Mallet finger.

Q16. A "Quadriga" effect occurs if:

Answer: A). FDP tendons share a common muscle belly.

Q17. Treatment for Mallet finger (non-bony) is:

Answer: A). Even 5 minutes of flexion can ruin 6 weeks of healing.

Q18. FDP Test involves:

Answer: A). Only FDP crosses the DIP joint.

Q19. "Lumbrical Plus" finger happens when:

Answer: A). Attempting to flex causes extension of IP joints.

Q20. Zone T1 refers to:

Answer: A). Thumb has separate zones (T1-T5).

Q21. Early Active Motion (EAM) protocols require:

Answer: A). To withstand the force of active muscle contraction.

Q22. Which nerve passes through the Carpal Tunnel (Zone IV)?

Answer: A). Risk of simultaneous injury.

Q23. Juncturae Tendinum connect:

Answer: A). They limit independent finger extension.

Q24. Extensor tendons are generally:

Answer: A). Making suture hold difficult.

Q25. Blocking splints are usually discontinued at:

Answer: A). When tensile strength is sufficient for light use.