Flexor Tendon Injuries Applied Anatomy & Examination Tendon Healing Management.
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Transcript of Flexor Tendon Injuries Applied Anatomy & Examination Tendon Healing Management.
Flexor Tendon Injuries
• Applied Anatomy & Examination
• Tendon Healing
• Management
Flexor Tendon Injuries
Applied Anatomy
Anatomy
• Musculotendinous units
• Synovial sheaths & Fibrosseous canals
• Pulleys
• Vascular supply
• Zones
Tendon Structure
• Composite material consisting of collagen fibrils embedded in a matrix of proteoglycans– Type I collagen (95%)– Type III and IV collagen (5%)
• Tenocytes are arranged in parallel rows between bundles
Tendon Structure
Tendon Structure
• Endotenon circumscribes each fascicle – Permits fascicular gliding
• Epitenon surrounds the tendon– Contains capillary blood supply
Tendon Structure
Epitenon
Endotenon
Paratenon
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
Applied Anatomy
• FDS
• FDP
• FPL
• N & V
FDS
FDP
Verdan Zones
Zone 5
Zone 5/4
Zone 3
Zone 2 – Campers Chiasma
Tendon Nutrition
Nutrient Supply
• Dual Source via Perfusion and DiffusionA. 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 the digital sheath. (Lundborg 1978, 1980)
Vascular Supply
Synovial Sheaths
Digital Sheaths
• Analogous to paratenon – Visceral layer surrounds
tendons
– Parietal layer contains thickenings that comprise the flexor sheath and pulley system
– Contains synovial fluid
Pulleys
Pulleys- A2 & A4
Biomechanics
• Moment arm-pulleys– Loss of pulleys increase
excursion necessary for desired flexion
Strickland OCNA 1983
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
Biomechanics
• 9 cm of tendon excursion is required for composite wrist & digital flexion– 2.5 cm for full digital flexion with wrist
stabilized
• Tendon excursion and joint rotation are controlled by pulley system
Summary
• Intrasynovial flexor tendon repair- leave sheath intact
• Preservation of A2 & A4 pulleys
• Digital arterial ladder branch is identified and preserved
Summary
• Thick skin flaps retracted with sutures
• Create windows in the membranous portion of the
flexor tendon sheath
• Blind passage of instruments into the tendon sheath should be avoided
Management of Flexor tendon Lacerations
• History
• Physical Examination
• Surgical Repair
• Rehabilitation
Examination
• Colour, Capillary Refill, Temperature
• Compare to non-injured hand
Circulation
Nerves - Sensory
Diagnosis of Flexor Injury
• Posture of Hand/ Normal cascade
• Passive tenodesis test
• Forearm compression test
• Independent testing of FDS & FDP
• Partial damage
Normal Flexion Cascade
Flexor Tendon Testing
FPL