Flexor Tendon Injury Fundamentals
Core principles for recognising, describing and planning flexor tendon injuries before definitive repair and rehabilitation.
Learning objectives
- Differentiate FDP and FDS function clinically.
- Understand why tendon zone and associated injuries matter.
- Recognise the importance of atraumatic handling and pulley preservation.
- Explain why rehabilitation is part of the operation, not an afterthought.
Clinical recognition
Loss of the normal finger cascade or inability to actively flex a joint after laceration should raise suspicion. FDP function is tested by stabilising the PIP joint and asking for DIP flexion. FDS function can be isolated by holding the other fingers extended while asking the test finger to flex at the PIP joint.
Zone matters
Flexor tendon injuries are described by anatomic zones because available space, pulley anatomy and nearby neurovascular structures change the technical problem and rehabilitation strategy.
Associated injury is common
Digital nerves and arteries run close to the flexor sheath. Document sensation and circulation before repair planning, and inspect for fracture, joint injury and contamination when mechanism suggests them.
Repair principles
Modern repair aims for sufficient strength to permit controlled early motion while minimising bulk and friction. Tendon handling, suture configuration, venting decisions and pulley preservation all influence glide.
Rehabilitation
A technically good repair can fail functionally through rupture or adhesions. Early protected mobilisation protocols require coordination with experienced hand therapists and patient adherence.
Delayed presentation
Late injuries may not be suitable for simple primary repair. Tendon retraction, scarring, pulley condition and joint stiffness influence whether reconstruction, grafting or staged procedures are required.
Case checkpoint
A kitchen-knife laceration lies at the proximal phalanx of the ring finger. The patient cannot flex the DIP joint but can flex the PIP joint. The pattern suggests FDP disruption with possible preservation of FDS; sensation on both sides of the digit still needs formal documentation.
Self-assessment
Q1. How is FDP function isolated?
Stabilise the PIP joint in extension and ask the patient to flex the DIP joint.
Q2. Why is injury zone clinically useful?
It describes the local anatomy and helps anticipate technical difficulty, pulley issues, associated neurovascular injury and rehabilitation considerations.
Q3. What nearby structures must be assessed?
Digital nerves and arteries, as well as bone and joint structures when indicated.
Q4. Why is repair strength important?
It must tolerate the planned protected mobilisation programme while maintaining tendon approximation.
Q5. What commonly limits final motion after repair?
Adhesion formation, joint stiffness, rupture and associated injury can all limit function.
Finished this module?
Save completion on this device. This is a learning-progress marker only and is not an accredited CME credit.