MSK growth/injury and repair: tendons and ligaments

Question 1

What are ligaments?

Answer 1

Dense bands of collagenous tissue that span a joint

They are anchored to the bone at either end and provide joint stability through range of motion.

Often they are divided into segments with slightly different orientations and that results in different portions of the ligament tensioned at different joint positions

Multiple ligaments in any one joint

Question 2

What makes up ligaments?

Answer 2

Collagen fibres (type 1)

Fibroblasts within them

Sensory fibres for proprioception, stretch and sensation/pain - first 2 are important for the brain to know where the joint is in time and space

Vessels on surface so they when they are damaged they bleed

Crimping - allows for stretch

Question 3

What’s the difference between ligaments and tendons?

Answer 3

Ligaments have lower % of collagen and a higher % of proteoglycans and water

Less organised collagen fibres

Rounder fibroblasts

Question 4

What is one of the most common joint that gets injured in ligament injuries?

Answer 4

The ankle joint - especially the lateral ligament

Question 5

How does a ligament rupture?

Answer 5

If the force put on the joint exceeds the strength of the ligament then it can rupture

Can be a complete or incomplete rupture

This is sometimes expected
but can be unexpected too (if joint is an abnormally sensitive position and the muscles aren’t contraction)

Question 6

How do ligaments heal?

Answer 6

There is an initial haematoma and as this is resorbed it creates an inflammatory hypertrophic vascular response and its replaced with a heavy cellular infiltrate

Proliferative phase - production of scar tissue. A disorganised collagenous connective tissue is laid down

Remodelling - the disorganised tissue is put under pressure and direction. The matrix becomes more ligament like however there is always a visual scar.

Question 7

Who should get conservative treatment for ligament damage?

Answer 7

Partial tear

Complete tear with no instability

And those who are poor candidates for surgery - liable to get more complications from attempting repair than from leaving them with ligament disruption

Question 8

Who should get operative treatment for ligament damage?

Answer 8

Instability of the joint resulting from ligament damage

Those with a high expectation of performance from their joint (sportsmen)

Compulsory - if you damage multiple ligaments around a joint the joint will be so unstable that it will need repaired

If it can’t be repaired then there should be replacement of the ligament

Question 9

What makes up tendons?

Answer 9

Longitudinal arrangement of cells (mostly tenocytes) and fibres (Collagen type 1)

Question 10

What does endotenon cover?

Answer 10

Collagen bundles

Question 11

What are fascicles covered by?

Answer 11

Paratenon

Question 12

The tendon itself is covered by what?

Answer 12

Epitenon

Question 13

How does the blood supply enter into the tendon?

Answer 13

Through vincula

Question 14

How are tendons connected to their tendon sheath?

Answer 14

By vincula and this is how the blood supply enters

The vincula

Question 15

What are the functions of pulleys?

Answer 15

They hold the tendon down to the bone

Question 16

Function of tendons

Answer 16

Flexible and very strong in tension - they pull on bones in order to bend joints and provide propulsion

Movement is life - if they become immobile the water content and glycosaminoglycan concentration and strength reduce

Question 17

Degeneration of tendons

Answer 17

Most commonly associated with the Achilles tendon

The tissue changes (intrasubstance mucoid degeneration). It may be swollen, painful, tender or patient may be asymptomatic.

In some cases this is a precursor to rupture of the tendon

Question 18

Inflammation of tendon

Answer 18

Most common = Quervain’s stenosing tenovaginitis

The tendons of EPB and APL passing through common tendon sheath at radial aspect of wrist - they become swollen, tender, hot and red.

Question 19

What is Enthesiopathy?

Answer 19

Inflammation at insertion to bone of muscle or tendon

It’s thought to be caused by repetitive action (tennis etc)

Question 20

Traction apophysitis?

Answer 20

Apophysitis results from a traction (movement of ligament or tendons over the bone) injury to the cartilage and bony attachment of tendons in children and adolescents.

Common type is Osgood Schlatter’s disease which is seen in adolescent active boys (not seen once growth plates have closed).

This affects the insertion of patellar tendon into the anterior tibial tuberosity. There’s an inflammatory component too.

Question 21

What is tendon avulsion?

Answer 21

When a tendon is torn off by either trauma or surgery

This happens when the load exceeds the failure strength while the muscle is contracting

Question 22

Mechanisms of rupture

Answer 22

Pushing off with weight bearing forefoot whilst extending knee joint e.g sprint starts or jumping movements

Unexpected dorsiflexion of ankle e.g slipping into hole

Violent dorsiflexion of plantar flexed foot e.g fall from height

Question 23

Treatment of tendon rupture

Answer 23

Conservative - splint/cast, mobilisation

Operative - for high risk rupture or individuals with very high activity

Question 24

Common causes of laceration of tendons

Answer 24

Handling sharp objects at work or injury whilst cutting food