Tendon Growth and Repair Flashcards
How is the composite unit of the muscle and tendon arranged?
- Muscle origin from bone
- Muscle belly
- Meuscultendinous junction
- Tendon (+/- sesamoid bone, tendon sheath)
- Tendinous insertion into bone (Sharpey’s fibres)
Describe the structure of tendon.
- Longitudinal arrangement of cells (mostly tenocytes) and fibres (collagen type 1-tirple helix)
- Fascicles of long narrow spiralling collagen bundles
How are tendons composed?.
- Collagen bundles covered by endotenon
- Fascicles covered by paratenon
- Tendon covered by epitenon
How are tendons attached to tendon sheaths?
Via vinicula
What is a tendon sheath?
- A tendon sheath is a layer of synovial membrane with fluid around a tendon
- It permits gliding lubrication and nutrition
What do the tendon sheaths in the distal palm and fingers act as?
They are thickenings which form strong annular pulleys
What happens if we lose mobility?
There is a reduction in water content and glycosaminoglycan concentration and strength
In what ways can tendons be injured?
- Degeneration
- Inflammation
- Enthesiopathy
- Traction apophysitis
- Avulsion +/-bone fragment *
- Tear - intrasubstance (rupture) *
- Tear - musculotendinous junction
- Laceration/ incision
- Crush / ischaemia / attrition
- Nodules
Give an example of a tendon prone to degeneration.
Achilles
How does Achilles tendon degeneration present?
- Intrasubstance mucoid degeneration
- May be swollen, painful, tender or may be asymptomatic
- Is a precursor to rupture
Give an example of a inflammatory condition of the tendons.
De Quervain’s stenosing tenovaginitis
What tendons are susceptible to de Quervain’s stenosing tenovagnitis?
Tendons of EPB + APL passing through common tendon sheath at radial aspect of wrist
How does de Quervain’s stenosing tenovaginitis present?
- Swollen, tender, hot, red
- Positive Finklestein’s test
What is enthesiopathy?
- Inflammation at insertion to bone
- Usually at muscle origin rather than tendon insertion
What does enthesiopathy present as in ligaments?
Plantar fasciitis
Give an example of traction apophysitis.
Osgood Schlatter’s disease
How does Osgood Schlatter’s disease?
- Insertion of patellar tendon into anterior tibial tuberosity
- Adolescent active boys
- Recurrent load
- Inflammation
What can avulsion +/- bone fragments result in?
Mallet finger
- Insertion of extensor tendon into dorsum of base of distal phalanx of finger
- Forced flexion of extended finger
Why does avulsion +/- bone fragments occur?
- Failure at insertion
- Load exceeding failure strength while muscle contracting
How is avulsion treated?
Conservative
- Limited application
- Retraction tendon
Operative
- Reattachment tendon through bone
- Fixation bone fragment
Why does intrasubstance rupture occur?
Load exceeds failure strength
What are the possible mechanisms of rupture?
- Pushing off with weight bearing forefoot whilst extending knee joint (53%) e.g. sprint starts or jumping movements
- Unexpected dorsiflexion of ankle (17%) e.g. slipping into hole
- Violent dorsiflexion of plantar flexed foot (10%) e.g. fall from height
How does Achilles tendon rupture appear on examination?
- ‘Positive’ Simmond’s squeeze test
- Palpable tender gap
Where do tears commonly occur of the musculotendinous junction?
Medial head of gastrocnemius at musculotendinous junction with Achilles tendon though often partial
