Musculoskeletal Growth/Injury and Repair - Ligament and Tendon Flashcards
What are ligaments? Function?
- Dense bands of collagenous tissue, some of which are just condensations of joint capsules
- Anchored to bone at each end, provide joint stability through ROM
What are the components of a ligament?
- Collagen fibres (type 1)
- Fibroblasts
- Sensory fibres (proprioception / stretch / sensory)
- Vessels at surface
What are the differences in composition between tendons and ligaments?
Ligaments are more compliant due to:
- lower percentage of collagen
- Higher percentage of proteoglycans and water
- Less organized collagen fibres
- Ligaments also have rounder fibroblasts
How does the resistance of ligaments vary with rate of force loading on them?
- Ligaments are stronger under faster rates of loading
What is a common complication of ligament ruptures? What is one of the commonest areas for ligament ruptures in the body?
- Loss of proprioception
- Ankle joint is very susceptible
What are the phases of ligament healing?
Haemorrhagic
Proliferative
Remodelling
What occurs in the haemorrhagic phase of ligament healing?
- Begins with large haematoma that is gradually resorbed
- Then triggers a hypertrophic vascular response and the blood is replaced with a heavy cellular infiltrate
What occurs in the Proliferative phase of ligament healing?
Production of scar tissue and laying down of disorganized collagenous connective tissue
What occurs in the Remodelling phase of ligament healing?
The collagenous matrix that has been laid down becomes slightly more organized and ligament-like
- Major differences in architecture, composition and function still persist though
Which patients are often given conservative (non-operative) treatment for tendon ruptures? What are some examples of conservative management?
Patients with partial or stable ligament injuries, or patients that are poor candidates for surgery
- Conservative management focuses on joint immobilization, so soft tissue braces up to casts etc.
Which patients tend to be given operative treatment for ligament injuries?
Unstable injuries (ACL), athletes and people with mulitple ligaments injured
What are some options for operative ligament rupture treatment?
- Direct repair
- Direct repair + augmentation (add tape to ligament to strengthen it)
- Ligament replacement (usually done with some tendon often taken from hamstrings & then attached to bones)
Via what structure do tendons attach to bone?
Sharpey’s fibres
Describe the composition of tendons
Composed mostly of tenocytes and collagen fibres (type 1)
longitudinal arrangement of cells
surrounded by tendon sheath
Describe the structural arrangement of tendons
- Long, narrow spiralling collagen bundles covered by endotenon
- Collagen bundles group to form fascicles which are covered by paratenon
- Fascicles group into tendons which are covered by epitenon
Describe the structure of the blood supply of tendons?
- Blood vessels located in the paratenon
- Blood vessels enter the tendons via vincula (vinculum)
How is the tendon sheath connected to the tendon in the flexors of the fingers? How does the tendon sheath help supply nutrition to the tendon?
- Connected via a vinculum
- Vincula contain blood vessels
- Often there is also synovial lining and fluid associated with the tendon sheath providing nutrition
In the fingers, how are the tendons associated with the bone?
There are thickenings of the tendon sheath that form strong annular pulleys that keep the tendon closely associated to the bone
- Prevents bow-stringing of tendon between bone and carpal tunnel
How does immobilization affect tendons?
Immobility reduces water content and glycosaminoglycan concentration
Also reduces strength
What happens during tendon degeneration? How may tendon degeneration present? Where does it commonly occur?
Intrasubstance mucoid degeneration
- Presents with swelling +/- pain or tenderness
- Occurs in achilles tendon
What is de quervain’s tendinitis? How does it present? Tests for diagnosis?
- Inflammation of EBP & APL at radial aspect of wrist
- Presents as swollen, tender +/- hot
- Positive Finklestein’s test
What is enthesiopathy? What is a common place for this to occur?
Inflammation at the insertion of the tendon onto the bone (more usually at the side of muscle origin)
At the elbow (tennis elbow)
(can also occur in ligaments - plantar fasciitis)
What is traction apophysitis? Common example? How does it progress?
- Damage to the apophysis of a bone that has not yet reached skeletal maturity (still have growth plates) caused by excessive pull by a tendon (exercise)
- Osgood-Schlatter’s disease (where patella tendon inserts onto tibial tuberosity)
- Pain resolves with rest, or as skeleton reaches maturity
What is tendon avulsion? Where does it commonly occur?
Pulling off of a tendon (load exceeds failure strength)
- May occur +/- a fragment of the bone the tendon attaches to
Commonly occurs at distal phalanx and in biceps
How is tendon avulsion treated?
If the tendon does not retract (finger) treatment can be conservative - splints
If the tendon retracts surgery is needed:
- reattach tendon through bone
- or fix bone fragment back on
What causes instrasubstance ruptures of tendons? Where do they commonly occur?
- Load exceeds the failure strength, often occurs in achilles tendon
In achilles tendon, mechanism of rupture:
- pushing off forefoot while extending knee
- unexpected dorsiflexion of ankle
- violent dorsiflexion of plantar flexed foot
What are some clinical examination tests for achilles tendon rupture?
- Feel for palpable tendon gap in ruptured tendon (not always present)
- Simmond’s test: patient lying prone, squeeze the gastrocnemius and the patients foot should plantar flex (positive if doesn’t flex - rupture)
What is a musculotendinous junction tear? How does it present? How are they usually treated?
- Tear at the junction between muscle belly and tendon
- Presents with severe pain + swelling
- Usually conservative treatment due to tears mostly being partial
When would tendon ruptures tend to be treated conservatively?
When the two ends of the tendon can be opposed (put close together - met up)
When would tendon ruptures be treated operatively?
- When the ends of the tendon cannot be opposed
- In highly active people
- When there is a high risk of re-rupture
What is the most common place for tendon laceration / incision? How are these treated?
- In the fingers and hands (FDS & FDP)
- Need to be surgically repaired early (if left untreated may need grafts to re-attach tendon ends)
