FunMed Week 2

Question 1

what is a tendon? [1]

what is it made from? [1]

Answer 1

•Tendons: a dense fibrous connective tissue that attaches muscle to bone

made from: composed of an abundant extracellular matrix (ECM) that is constituted mainly of collagen molecules, which are organized into fibrils, fibers, fiber bundles and fascicles helicoidally arranged along the largest axis of the tendon.

Question 2

what do tendons and ligaments attach?

Answer 2

tendons: skeletal muscle to bone
ligaments: bone to bones

Question 3

what is the definition of medial epicondylitis? [1]

what is it caused by? [1]

what does it present as? [1]

Answer 3

what is the definition of medial epicondylitis? [1]
inflammation of the medial epicondyle due to overuse injury of the wrist flexor tendons.

what is it caused by? [1]
excessive activity involving wrist flexion

what does it present as? [3]
medial epicondyle elbow pain
On examination:
- Pain on palpation(tenderness) of the medial epicondyle
- pain with
•resisted wrist flexion while the elbow is extended
•passive wrist extension while the elbow is extended

Question 4

how do you manage medial epi? [3]

Answer 4

• Activity modification in this scenario bowling
• Physical therapy through physio to do exercises that would accelerate healing
• Non-steroidal anti-inflammatory drugs (NSAIDs) for pain-relief

Question 5

1. Name the three joints of the elbow and describe the type of movement they permit. (3 marks)

Answer 5

Humero-ulnar joint (1/2 mark) is formed between the humerus and ulna and allows flexion and e etension of the arm (1/2 mark).

Humero-radial (radio-capitellar) joint (1/2 mark) is formed between the radius and humerus, and allows movements like flexion, extension, supination and pronation (1/2 mark).

Proximal Radio-ulnar joint (1/2 mark) is formed between the ulna and radius bones, and allows rotation of the lower arm (1/2 mark).

Question 6

1. Define medial epicondylitis (1 mark)

Answer 6

Medial epicondylitis, also called thrower’s or golfer’s elbow, is a condition caused by an infl- ammation (‘itis’ at the end indicates inflammation of) in the tendon (1/2 mark) that connects the w wrist flexor pronator muscles to the medial epicondyle on the humerus (1/2 mark).

Question 7

1. What is the main molecular component of tendons and what particular property makes it fundamental to this role? (2 marks).

Answer 7

1. Tendons are mainly composed of collagen fibres (1 mark). Collagen is a tough fibrous protein formed from long intertwined strands (1/2 mark) that give high durability and strength and can therefore take mechanical stress without breaking the tissue (1/2 mark).

Question 8

1. How are the symptoms of medial epicondylitis distinguished from lateral epicondylitis (tennis elbow)? (1 mark)

Answer 8

1. In medial epicondylitis pain is felt on the inside of the elbow on the palm side, while for lateral epicondylitis pain is felt on the outside of the elbow. Both present with weakened grip.

Question 9

1. What is the difference between glycoproteins and proteoglycans and give examples of each found in tendons or ligaments? (3 marks)

Answer 9

1. Glycoproteins are proteins that have a carbohydrate covalently linked to them, where the carbohydrate may be a mono-, di- or polysaccharide or other carbohydrate derivatives (1 mark).

Examples found in tendons/ligaments: elastin, COMP, lubricin, tenascin-C, tenomodulin (1/2 mark for any)

2/ Proteoglycans are a type of glycoproteins in which the sugar part is a polysaccharide that contains amino sugars (1 mark).

Examples found in tendons/ligaments: small leucine –rich proteoglycan or SLRPs such as decorin, aggrecan, versican. (1/2 mark for any)

Question 10

how would you treat medial epi?

1st line?
2nd line?
3rd line?

Answer 10

how would you treat medial epi?

1st line: rest + ice + NSAID + brace / strap
2nd line: physiotherapy ± local anaesthetic injection​
3rd line: surgery

Question 11

what is main role of tendon? [2]

Answer 11

transmit forces from the muscle to the bone and absorbs external forces to prevent injury to the muscle.

Question 12

what is main component of tendon? [1]

characteristics of tendons? [3]

Answer 12

collagen (85%)

characteristics:

• flexible so that it can bend at joints
• damping tissue to absorb shock
• elastic energy can be stored and used as elastic recoil

Question 13

what is the pathophysiology of medial epi?

Answer 13

Microtears in the muscles originating at the elbow are the probable pathological process resulting in the symptoms of both lateral and medial epicondylitis

Question 14

where do lesions specifically occur in medial epi ? [5] !!

Answer 14

In medial epicondylitis, lesions may occur in the pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, and flexor carpi ulnaris

All these muscles have the same origin: the medial epicondyle of the humerus. Most frequently the pathology occurs in the musculotendinous origin of the flexor carpi radialis and pronator teres. But large diffuse tears can also occur in the palmaris longus, flexor digitorum superficialis and flexor carpi ulnaris.[2]

Question 15

after injurt what are damaged tendons characterised by? [2]

Answer 15

After injury, damaged tendons are characterised by signs of oedema, with disruption of the normal parallel orientation of the collagen fibres.

Question 17

what happens with medial epi recovery to tendon? [1]

Question 18

what movements may cause increased pain with medial epi? [2]

Answer 18

Pain may radiate along the medial elbow and be increased with resisted forearm pronation or wrist flexion[8]

Question 19

risk factors for medial epi?

Answer 19

• increasing age
• repititve activities
• history of medial epi
• poor mechanics doing activity
• smoking

Question 20

what is structure of ligaments?

• mainly consists of ? [1]
• also? [2]
• which cells? [1]

Answer 20

principally type 1 collagen (image is of the triple helix, collagen) which accounts for approximately 75% of the dry weight with the balance being made up by proteoglycans (<1%), elastin and other proteins and glycoproteins.

composed of cells called fibroblasts which are surrounded by matrix.

Question 21

how do ligaments heal? [3]

Answer 21

Hemorrhage with inflammation - involves retraction of the disrupted ligament ends, formation of a blood clot, which is subsequently resorbed, and replaced with a heavy cellular infiltrate.

Matrix and cellular proliferation - defined as the production of “scar tissue” (dense, cellular, collagenous connective tissue matrix) by hypertrophic fibroblastic cells. After a few weeks of healing, the collagen becomes quite well aligned with the long axis of the ligament despite the fact that the types of collagen are abnormal and the collagen fibrils have smaller diameters in the proliferating tissue.

Remodeling and maturation (matrix remodeling) - defects in the scar become filled in but although the matrix becomes more ligament-like with time, some major differences in composition, architecture and function persist. Differences which persist include altered proteoglycan and collagen types, failure of collagen crosslinks to mature, persistence of small collagen fibril diameters, altered cell connections, increased vascularity,

Question 22

what are stages of tendon repair?

Answer 22

Reactive Tendinopathy
The cells change shape and have more cytoplasmic organelles for increased protein production (proteogycans and collagen) (On imaging the tendon does appear to be thickened and swollen due to the changes in the proteogycans)

Tendon Dysrepair
During this phase, there is the continuation of increased protein production which has been shown to result in separation of the collagen and disorganisation within the cell matrix.
Also, there may be evidence of increased vascularity and neural ingrowth within the tendon.

Degenerative Tendinopathy

Question 23

cellular component of a tendons?

• which cells make up 90% [2]
• which cells make up 10%? [3]

what is ECM like? [2]

what is innervation like? [2]

Answer 23

cellular:
The tendon cells are known as tenoblasts and tenocytes. They make up approximately 90-95% of the cells within the tendon. The other 5-10% include the chondrocyctes, synovial cells and the vascular cells.[1]

The tenocyctes respond to mechanical load of the tendon and thus make adaptations.

Tendons consist of mainly type 1 collagen fibres (but there are others present) and proteoglycan. The type 1 collagen fibres are responsible for the tensile strength of the tendon whereas the proteoglycan are responsible for the viscoelastic nature of the tendon.

ECM

The orientation of the collagen fibres in tendons have been found to run; parallel, simply crossing, crossing of two fibres with one straight, a plait formation of three fibres and an up typing of two parallel running fibres.

Innervation

The innervation of tendons start from cutaneous, peritendinous and muscular nerves. At the MTJ nerve fibres cross and enter the endotenon and the paratenon. These fibres then enter and innervate the epitenon. The majority of the nerve fibres terminate and reside on the surface of the tendon. The nerve endings can be categorised into myelinated and unmyelinated. The myelinated nerve fibers are specialized mechanoreceptors (Golgi tendon organs) sensing tension and pressure in the tendon. These tend to be located close to the muscle. The unmyelinated fibres are responsible for sensing and transmitting pain (nocioceptors). [12][13]

Question 24

what is difference between tensile strength or short and long tendon? [2]

what is the difference in deformaity of short and long tendon? [2]

Answer 24

A short tendon has a greater tensile strength than a long tendon because the load required to produce the break is much larger in the short tendon with the same diameter.

A long tendon can undergo a greater deformation than that of a short tendon before going to rupture. S

Question 25

what changes occur to tendons with increased age? [3]

Answer 25

The tendon is less able to adequately pilot the force expressed by the muscle toward the bone tissue.

Collagen fibers are less organized;

lower number of fibroblasts and senescent cells and a decrease in the amount of water and the number of proteoglycans, with reduced viscoelastic properties.