Tendinopathy Flashcards
(26 cards)
What is the composition of a tendon?
densely packed, slightly wavy type I collagen bundles
- held together by proteoglycans
Sparsely interdispersed tenocytes
What is the role of a tenocyte?
specialist fibroblast which secretes extracellular matrix
What is the role of the proteoglycans in a tendon?
hold together the collagen fibres to provide resistance to compressive forces
What is the role of collagen in a tendon?
allow resistance to tensile and stretching forces
What is the paratenon?
The outer layer of the tendon - reducing the friction forces
What is the endotenon?
surrounds each fibre bundle to bind them together and allow gliding/sliding
what is the epitenon?
Under the paratenon - surrounds the tendon
what is the peritendon?
the epitenon and paratenon together surrounding the entire tendon
What is the blood supply to a tendon?
sparse network within the endotenon - originates from osteotendinous and musculotendinous junctions
What is tendinopathy?
overuse injury of a tendon - load placed on the tendon exceeds the tendons capacity
What type of forces cause mid-portion Achilles tendinopathy?
tensile overload
What type of forces causes insertion Achilles tendinopathy?
compressive overload
How does a tendon help to transmit forces?
Stretch-shortening cycle - acts like a spring - energy is stored and released to allow propulsion
What is the principle of intrinsic factors for tendinopathy?
When the rate of damage is greater than the rate of repair resulting in degeneration
Examples of intrinsic risk factors for tendinopathy? (5)
- Older age
- Male
- weight gain
- Reduced muscle power
- Altered biomechanics (e.g. reduced DF or over-pronation)
What are the extrinsic risk factors for tendinopathy?
Changes in loading - e.g. hills/increasing speed
Change in intensity or type of training
Training errors
Recent LL injury
What are the 3 overlapping phases of tendinopathy?
- Reactive tendinopathy
- Tendon disrepair
- Degenerative tendinopathy
What occurs during the reactive tendinopathy phase?
Initial response to excessive load/compressive forces:
- non-inflammatory poliferative response
- activation of tenocytes –> increased proteogylcans –> increased water content –> change in ground substance –> SWELLING
Why does swelling occur in reactive tendinopathy?
to reduce stress by increasing cross sectional area OR to allow adaptation to compression
What occurs during the tendon disrepair phase?
Tendon attempts to heal but reactive tendinopathy has not been managed - resulting in failed healing
- increased number of tenocytes –> cell metaplasia (means that the tenocytes are like chondrocytes) –> increased myofibroblasts
- neovascularisation
OVERALL, separation of collagen fibres and disorganisation of the matrix
What occurs during the degenerative tendinopathy phase?
- Areas of cell death due to tenocyte exhaustion
- Areas form without cells - filled with matrix breakdown products
- Large areas of disorganized matrix - filled with blood vessels ISLANDS OF DEGENERATION
- Very little collagen is present
What is teh clinical presentation of tendinopathy?
- HIghly localised pain and swelling
- Pain onset after unaccustomed training OR following trauma
- Latent pain after exercise
- Pain after rest
- Some stiffness on rising or after resting
Why is mid-portion achilles tendinopathy more common?
hypovascular 2-7cm above calcaneal insertion point
What is a subfasicle?
AKA primary fibre bundle - 10-20 collagen fibres bound by endotenon
