Flexor Tendon Injuries2

8/7/2019 Flexor Tendon Injuries2

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Flexor Tendon Injuries Applied Anatomy & Examination

Tendon Healing

Management


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Flexor Tendon Injuries


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Applied Anatomy


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Anatomy Musculotendinous units

Synovial sheaths & Fibrosseous canals

Pulleys

Vascular supply

Zones


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Tendon Structure

Composite material consisting of collagenfibrils embedded in a matrix of proteoglycans

Type I collagen (95%)

Type III and IV collagen (5%) Tenocytes are arranged in parallel rows

between bundles


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Tendon Structure


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Tendon Structure

Endotenon circumscribes each fascicle

Permits fascicular gliding

Epitenon surrounds the tendon

Contains capillary blood supply


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Tendon Structure

Epitenon

Endotenon

Paratenon


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Tendon Structure

Paratenon is the adventitia that covers

the flexor tendon in the palm

Consists of visceral & parietal layer

Continuous with synovial mesotenon

Supplies tendon nutrients

Allows tendon gliding


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Applied Anatomy FDS

FDP

FPL

N & V


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FDS


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FDP


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FPL

FDP


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Verdan Zones


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Zone 5


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Zone 5/4


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Zone 3


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Zone 1/2


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Tendon Nutrition


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Nutrient Supply Dual Source via Perfusion and Diffusion

A. Perfusion from blood supplied by longitudinal

vessels as well as the vincula system.

B. Diffusion within the sheath is via synovial

fluid.

Diffusion is more important within thedigital sheath. (Lundborg 1978, 1980)


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Vascular Supply


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Synovial Sheaths


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Pulleys


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Pulleys- A2 & A4


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Biomechanics

Forces generated during tendon function

Passive flexion 2-4 N

Active with mild resistance 10N

Active with moderate resistance 17N Strong grasp 70N

Tip pinch 120N

Power grip 200N

(FDS 30% < FDP, loads increased by edema/scar)

Schiund et al JHS 1992


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Summary Intrasynovial flexor tendon repair- leave

sheath intact

Preservation of A2 & A4 pulleys

Digital arterial ladder branch is identified

and preserved


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Summary Thick skin flaps retracted with sutures

Create windows in the membranous portion of theflexor tendon sheath

Blind passage of instruments into the tendon

sheath shouldbe avoided


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Management of Flexor tendonLacerations

History

Physical Examination

Surgical Repair

Rehabilitation


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Examination Colour, Capillary Refill, Temperature

Compare to non-injured hand


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Circulation


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Nerves - Sensory


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Diagnosis of Flexor Injury

Posture of Hand/ Normal cascade

Passive tenodesis test

Forearm compression test

Independent testing of FDS & FDP

Partial damage


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Normal Flexion Cascade


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Flexor Tendon Testing


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FPL


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Documents

Flexor Tendon Injuries2