Tendon Injuries

  • What are tendons?

    • they are the mechanical bridge connects the muscle to the bone to allow for joint movement

    • lots of tensile strength

    • weak to shearing/compression

    • 60-80% of tendon is water

    • stretch 2-4% then tears

    • heals more slowly then muscles

    • get stonger whn putting weight on conitantly

    • go thro same stages of healing

  • tendon layers

    • layer 1

      • endotenon

      • covers fibers

    • layer 2 epitenon

      • dense shealth surounds

    • layer 3 paratenon

  • flexor tendon

    • intrisic blood suply thro vincula

    • synovial fluid id the primary source of nutrition (tendon gluides)

  • synocial shealth

    • synovial bursa

  • fingers pulleys

    • create tunnel system of flexor tendons are lying undernealth

  • ZOne 2-3 injuries are the worse

  • thumb tendon structure

    • synovia bursa surronds fpl & insirts into distal phalanx

•Extrinsic healing occurs by recruitment of surrounding fibroblasts and inflammatory cells to create scar formation in immobilized tendons

•Intrinsic healing activates tenocytes in the endotenon and epitenon, contributing to scarless healing based on the early mobilization of tendon injuries

Primary repair:  (<24 hours) is ideal.  Contraindicated with infection/risk of infection (human bite) or soft tissue trauma (major)!!!!!!!!!!!!!!!!! BEST

Delayed primary repair: (>24 hours, yet <2 weeks) constitutes a reasonable approach for heavily contaminated wounds and provides functional results comparable to initial primary repair. GOOD IF THERE IS INFECTION

Secondary repair: (2 to 5 weeks).  Risks include infection and prolonged edema.  Greater than 5 weeks: Risks include muscle atrophy, tendon edema, and softening in the setting of a scarred flexor tendon sheath that reduces the likelihood of good tendon gliding. May need a tendon graft or tendon transfer if the muscle has atrophied.  WORST!!!!!!!!!!!!!!

2-strand repair  - Immediate passive motion protocol only

4-strand repair - gentle active motion only (GOLD STANDARD)

6-strand repair – Immediate Active Motion!!! (May be bulky, reduce gliding under the pulleys resulting in adhesions or rupture)

•Tensile Strength: the amount of force a tendon will tolerate before rupture. 

•A repaired flexor tendon is weakest between 5–21 days after surgery (inflammatory stage)

•“Move it, don’t use it” up to week 4.

•Most protocols (EAM, Modified Duran) begin light strengthening at week 8.

•During the remodeling phase, the tendon continues to strengthen (increased collagen).

•Appropriate mechanical loading of repaired tendons stimulates collagen growth in the direction of the tension

•At 12 weeks, most tendon repairs have adequate strength for functional activities. (3 month rehab)

•In weeks 12-14, most clients will resume normal activities (heavy gripping – tool use, sports)

ZONES OF HAND

ZOne 1

Distal to FDS insurtion

-FDP only

Juersy finger

Flexor Zone 2

hardest repair

A1 pully porximal edge to the distal insturtion of FDS

Flexor ZONE 3

ZONE 4

Zone 5

Immediate Passive Motion Protocols

•Modified Duran Protocol

•Kleinert Protocol

Immediate Active Motion Protocols

•Early Active Motion (Indiana) Protocol

•Brigham and Women’s Early Active Motion

“True Active Movement Protocol”

•St. John Protocol

Modified Duran Protocol (Indiana or BWH)

-Goal: to protect the repaired tendons while preparing the hand for functional use.

-Orthotic: Use a dorsal forearm-based blocking orthosis

-Exercises performed within the confines of the DBS

=DBS worn up to 6 weeks

-Active motion is usually initiated around 4 weeks.

-Pros: Best protocol for children or people with diminished mental capacity (higher risk of rupture in these populations). Also, patients who are not taking their injury/surgery seriously. Patients with significant soft tissue injury or concomitant crush injury. 

Kleinert Protocol

Goal: to protect repair while providing active extension/asstive flexion

Orthosis Dorsal block splint: o the fingernail of the affected finger.

Exercises: Active extension within the limits of the dorsal blocking splint with 50 repetitions each hour. In addition, passive flexion to the PIP & DIP joints, followed by composite passive flexion to each digit (5 repetitions per hour).

DBS worn up to 6 weeks

Active motion is usually initiated around 4 weeks.

-Pros: Some research indicates that the mobilized tendon showed less adhesion and a faster healing rate than the prolonged immobilized tendon.


Extensor tendons

•More thin and broad than flexor tendons

•Weaker in capacity for work, but require more mobility than flexor tendons

•More susceptible to injury as they lie closer to the skin surface

Dorasl comparments

•1 – EPB, APL

•2 – ECRB, ECRL

•3 – EPL

•4 – EDC, EI

•5 – EDM

•6 - ECU


odd zones joints, even zones bones

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