32. Conditions affecting the elbow

Question 1

What is the common mechanism of supracondylar fractures?

Answer 1

falling from a moderate height onto an outstretched hand with the elbow hyperextended e.g. a child falling off ‘monkey bars’

Question 2

Who are more prone to supracondylar fracture?

Answer 2

90% of supracondylar fractures are seen in children younger than 10 years of age, with a peak age of 5-7 years. They occur more
commonly in boys.

Question 3

What are the presentations of supracondylar fractures ?

Answer 3

The child presents with pain, deformity and loss of function.

Question 4

Describe the appearance of supracondylar fracture

Answer 4

In supracondylar fractures, the fracture line is usually extraarticular (i.e. the joint is not involved) and the distal fragment is usually displaced posteriorly

Question 5

What are the 3 main complications with supracondylar fractures?

Answer 5

• Malunion, resulting in cubitus varus.
• Damage to the median nerve (most common), radial nerve or ulnar nerve
• ischaemic contracture - brachial artery inhury

Question 6

How does Ischaemic contracture occur in supracondylar fractures?

Answer 6

• The brachial artery passes very close to the fracture site and can occasionally be damaged or occluded by a displaced fracture.
• Collaterals can usually maintain circulation to forearm and hand
• If reflex spasm of the collateral circulation around the elbow also occurs, there will be
ischaemia of the muscles in the anterior compartment of the forearm.
• This results is oedema and a rise in compartment pressure (compartment syndrome) which further exacerbates the ischaemia as it impedes arterial inflow and, if untreated, the muscle bellies will undergo infarction.
• During the repair phase, the dead muscle tissue becomes replaced by scar tissue through fibrosis.
• The fibrotic tissue contracts (by myofibroblast activity) eventually resulting in a flexion contracture known as Volkmann’s ischaemic contracture

Question 7

How does the arm appear in ischaemia contracture resulting from supracondylar fractures?

Answer 7

wrist is typically flexed, the fingers are extended at the metacarpophalangeal joints and flexed at the interphalangeal joints, the forearm is often pronated and the elbow is flexed

Question 8

How is risk of supracondylar fractures complications reduced and what should be done if there is a risk of complication?

Answer 8

Prompt and thorough neurovascular examination is conducted in any patient with a supracondylar fracture. If there is any compromise of the neurovascular supply of the forearm or hand, emergency reduction and fixation of the fracture (under anaesthetic) is required

Question 9

What is the normal mechanism for elbow dislocation?

Answer 9

when a person, often a child, falls on their
outstretched hand (FOOSH) with the elbow partially flexed

Question 10

Why are elbow dislocations most likely to occur mid-flexion?

Answer 10

The configuration of the bones contributes most to stability of the elbow in full extension and flexion, whereas the stability of the elbow in mid-flexion is more reliant on the ligaments, making dislocation most likely to occur in mid-flexion

Question 11

how are elbow displacements named?

Answer 11

elbow dislocations are named by the displacement of the distal fragment (i.e. the ulna and radius), not the proximal fragment (humerus)

Question 12

Describe posterior elbow dislocations

Answer 12

Over 90% of elbow dislocations are posterior. The distal end of the humerus is driven through the joint capsule anteriorly. The ulnar collateral ligament is usually torn and there can also be an associated fracture and/or ulnar nerve involvement

Question 13

Describe anterior elbow dislocations

Answer 13

Anterior dislocations (<10%) are usually the result of a direct blow to the posterior
aspect of a flexed elbow. Associated fractures of the olecranon are commonly seen with anterior dislocations due to the degree of force required to dislocate the joint

Question 14

What is a pulled elbow?

Answer 14

Pulled elbow refers to a subluxation of the radial head (subluxation = “partial disruption of a joint with some remaining but abnormal apposition of the articular surfaces” i.e. it is an incomplete dislocation).

Question 15

Who does a pulled elbow normally occur in? What do they present with?

Answer 15

most commonly occurs in children aged 2-5 years. The child presents with reduced movement of the elbow and pain over the lateral aspect of the proximal forearm. The parent often states that they are ‘not using their arm’.

Question 16

What is the mechanism of injury of a pulled elbow?

Answer 16

mechanism of injury is when longitudinal traction is applied to the arm with forearm pronated (e.g. tugging an uncooperative child or swinging a child by their arms during play).
However studies have shown that this mechanism is only actually reported in approximately 50% of patients, with the remainder of cases occurring during falls or over-reaching for an object.

Question 17

Describe what happens to the arm during a pulled elbow?

Answer 17

• The injury occurs most commonly in pronation because the annular ligament is
taut in supination and more relaxed in pronation, so it is easier for subluxation
to occur.
• The longitudinal traction on the radial head tears the distal attachment of the annular ligament from where it is loosely attached to the neck of the radius. The radial head is then displaced distally through the torn ligament.

Question 18

Why is a pulled elbow less common in older children?

Answer 18

As children age, the annular ligament naturally strengthens, making the condition
less common

Question 19

What may result in a radial head an neck fracture? What do the patient present with?

Answer 19

• result from a fall on an outstretched hand when the radial head impacts on the capitellum of the humerus.
• The patient presents with pain in the lateral aspect of their proximal forearm and loss of range of movement.
• The swelling associated with these fractures is usually modest in comparison with supracondylar fractures for example.

Question 20

How can you identify radial head and neck fractures on an x-ray?

Answer 20

• Occult (hidden) fracture
• the ‘fat pad sign’ (or ‘sail sign’) indicates that an effusion is present.
• In the setting of trauma, this is likely to be due to a haemarthrosis (blood in the joint) secondary to an intra-articular fracture.
• The ‘sail sign’ is so-named because it has the shape of a spinnaker sail.
• It is caused by displacement of the anterior fat pad.
• The displaced fat pad is relatively radio-lucent and therefore appears black on the X-ray.
• The patient also may also have a posterior fat pad sign due to displacement of the crescent of fat that is usually located within the olecranon fossa.

Question 21

In supracondylar fractures of distal humerus, what is the treatment for unidisplaced and displaced fracture?

Answer 21

• Undisplaced: Collar & Cuff +/- POP ‘back-slab’

* Displaced: Surgery (manipulation under anaesthetic (MUA) +/- K-wire stabilisation)

Question 22

What is the treatment for radial head and neck fractures?

Answer 22

• Sling and early ROM
– if minimally displaced
• Surgery

Question 23

Why is osteoarthritis of the elbow relatively uncommon?

Answer 23

because of the well-matched joint surfaces and strong stabilising ligaments. As a result, the elbow can tolerate large forces without becoming unstable, so there is less ‘wear and tear’ with age.

Question 24

Who are more likely to get osteoarthritis of the elbow?

Answer 24

OA of the elbow is more commonly seen in men than women (ratio 4:1) and is most common in manual workers and athletes who engage in sports that involve throwing (e.g. baseball, javelin, shotput). As with OA in other joints, it can be primary or secondary (e.g. ‘post-traumatic’ following a fracture, dislocation, etc).

Question 25

What do patients with OA of the elbow present with?

Answer 25

• Patients usually report a ‘grating sensation’ (crepitus) or locking (caused by
loose fragments of cartilage) in their elbow. • Swelling occurs relatively late and is due to an effusion.
• Osteophytes can impinge on the ulnar nerve, causing paraesthesia +/- muscle weakness.
• Stiffness of the elbow is tolerated relatively well by patients, especially loss of extension, as this results in little limitation of
their daily activities.

Question 26

What is the treatment for OA of the elbow?

Answer 26

Treatment only if symptomatic
– Injections
– Surgical Debridement
– Rarely: Total Elbow Replacement

Question 27

What is rheumatoid arthritis?

Answer 27

• Rheumatoid arthritis is an autoimmune disease in which autoantibodies, known as rheumatoid factor, attack the synovial membrane.
• The inflamed synovial cells proliferate to form a pannus, which penetrates through the cartilage and adjacent bone, leading to joint erosion and deformity.
• Rheumatoid arthritis particularly affects the metacarpophalangeal joints (MCPJ) and proximal interphalangeal joints (PIPJ) of the hands, the feet and the cervical spine.
• It can also involve the large joints.
• The autoimmune process also leads to damage to other organs, including the eyes, skin, lungs, heart and blood vessels and the kidneys.
• Patients with rheumatoid arthritis
also commonly have anaemia of chronic disease

Question 28

Who are most commonly affected by rheumatoid arthritis?

Answer 28

• Approximately 1% of the population are affected by rheumatoid arthritis and
the peak age of onset is 40-50 years
• but there is also a juvenile form that
affects children.
• Women more commonly affected than men in a 2:1 or 3:1 ratio.

Question 29

What are the e X-ray features of rheumatoid arthritis

Answer 29

 Joint space narrowing
 Periarticular osteopenia
 Juxta-articular (also called marginal) bony erosions (in noncartilage protected bone)
 Subluxation and gross deformity

Question 30

How is rheumatoid arthritis managed?

Answer 30

predominantly managed medically rather than surgically through prescription of disease-modifying medication. However, sometimes in severe cases, surgery is required to relieve pain and to improve mobility

Question 31

Who are mainly affected in Lateral elbow tendinopathy (‘tennis elbow’)?

Answer 31

LET has a prevalence of approximately 3% in persons aged 40-60 years.
As well as tennis players, painters, plumbers and carpenters are particularly prone to ‘tennis elbow’ due to the repetitive nature of their activity at the wrist
and elbow

Question 32

What does Lateral elbow tendinopathy usually present with and why?

Answer 32

• The patient will typically experience pain over the lateral epicondyle during extension of the wrist, especially if this is against resistance.
• The extensor carpi radialis brevis (ECRB) muscle normally helps to stabilise the wrist when the elbow is straight. This occurs during a tennis groundstroke, for example. When the ECRB is weakened from overuse, microscopic tears form in the tendon where it attaches to the lateral epicondyle. This leads to inflammation and pain.

Question 33

How is lateral elbow tendinopathy treated?

Answer 33

• Patients are advised to modify their activities to give the tendon an opportunity to heal.
• The disorder is usually self-limiting and 90% of patients recover within 1 year.
• Sometimes physiotherapy and bracing are required and a small number of patients need injections or surgery

Question 34

What is golfer’s elbow called medically?

Answer 34

Medial elbow tendinopathy

- tendinopathy of the common flexor tendon

Question 35

Where is the most common site of pathology in medial elbow tendinopathy?

Answer 35

interface between the pronator teres and the flexor carpi radialis (FCR) origins

Question 36

When is pain typically experienced in medial elbow tendinopathy?

Answer 36

Pain is produced on resisted flexion or pronation of the wrist. Patients present with an aching pain over the medial elbow, often noticed during the acceleration phase of throwing

Question 37

Who are more prone to medial elbow tendinopathy?

Answer 37

MET is associated with golfing and with throwing sports that place valgus stress on the elbow. It has also been reported in bowlers, archers and weightlifters.

Question 38

What might also be involved in medial elbow tendinopathy?

Answer 38

Ulnar nerve symptoms are present in up to

20% of cases due to the proximity of the ulnar nerve to the medial epicondyle

Question 39

How is medial elbow tendinopathy treated?

Answer 39

Usually self limiting, simple activity modifications. Physiotherapy and bracing are required and a small number of patients need injections or surgery

Question 40

What are 3 common causes of swelling around the elbow?

Answer 40

• Olecranon bursitis
• Rheumatoid nodules
• Gouty tophi

Question 41

What is olecranon bursitis?

Answer 41

inflammation of the olecranon bursa, situated between the skin and the olecranon process of the ulna

Question 42

What are olecronon bursitis usually due to?

Answer 42

• Repeated minor trauma (e.g. students leaning with their elbows on the desk for many hours whilst studying), in which case the contents will be serous fluid
• infection of the bursa (septic bursitis e.g. following a minor penetrating injury to the elbow)

Question 43

What are the characteristics of an olecronon bursitis?

Answer 43

Swelling is soft, cystic (fluid-filled) and transilluminates

Question 44

How is (non-septic) olecronon bursitis treated?

Answer 44

Treatment is conservative with compression bandaging +/- aspiration. A hydrocortisone injection is sometimes necessary in chronic cases

Question 45

How is septic olecronon bursitis treated?

Answer 45

aspiration, compression and antibiotics are required. Occasionally surgical drainage and washout under anaesthetic will be needed to resolve the infection

Question 46

What are rheumatic nodules?

Answer 46

commonest extra-articular manifestation of rheumatoid arthritis (RhA), and affect 20% of patients with RhA.

Question 47

Which RA patients are rheumatic nodules associated with and what else are they more prone to?

Answer 47

• Patients who develop rheumatoid nodules tend to be smokers and tend to have more aggressive joint disease.
• They are also more prone to other extra-articular (i.e. outside of the joint) manifestations of rheumatoid disease including vasculitis (inflammation of blood vessels) and lung disease.

Question 48

Where do rheumatoid nodules normally appear?

Answer 48

usually occur over exposed regions that are subject to repeated minor trauma. As well as affecting the elbow region, they can be seen in the fingers and forearms and occasionally over the back of the heel. They are usually nontender although the overlying skin can occasionally ulcerate and become infected.

Question 49

What is the treatment for rheumatic nodules?

Answer 49

improving medical control of the underlying rheumatoid disease, although the response of existing nodules to this is somewhat variable.

Question 50

What is gout?

Answer 50

Inflammatory condition resulting from defective purine metabolism leading to an increased production of uric acid. As the uric acid concentration increases in the blood, supersaturation and precipitation occurs, forming crystals of monosodium urate in the synovial cavity of joints, in tendons and in the surrounding tissues. These urate crystals trigger an innate immune response leading to acute inflammation

Question 51

How is gout treated in the acute phase?

Answer 51

treated medically with anti-inflammatory drugs during the acute phase

Question 52

How is gout treated once the acute phase is over?

Answer 52

xanthine oxidase inhibitors such as allopurinol (a purine analogue) can then be prescribed to reduce the production of uric acid and reduce the risk of further attacks

Question 53

What are gouty tophi?

Answer 53

nodular masses of monosodium urate crystals deposited in the soft tissues

Question 54

What causes gouty tophi?

Answer 54

They are a late complication of hyperuricaemia and develop in >50% of patients with untreated gout

Question 55

What are the complications of gouty tophi?

Answer 55

Usually painless, but complications can include pain, soft tissue damage and deformity, joint destruction and nerve compression

Question 56

Where do gouty tophi commonly occur and what is their appearance?

Answer 56

Common sites are the fingers and the ears, but tophi can also be found in the olecranon bursa and the subcutaneous tissues of the elbow, where they can resemble rheumatoid nodules in appearance.
They contain white ‘pasty’ material and, as they enlarge, they work their way towards the skin surface to drain, either forming a sinus tract or a continuously draining ulcer

Question 57

Where does the ulnar nerve go through in the forearm and elbow?

Answer 57

The ulnar nerve passes behind the medial epicondyle of the humerus to enter the forearm, and is therefore in close proximity to the elbow joint
The flexor carpi ulnaris muscle has two heads, one head originating from the common flexor origin on the medial epicondyle and a second head originating from the medial margin of the olecranon (here). These two heads are united by a tendinous arch. The ulnar nerve passes beneath this tendinous arch to enter the cubital tunnel

Question 58

Where is the common site for ulnar nerve compression (cubital tunnel syndrome)?

Answer 58

At the tendinous arch of the flexor carpi ulnaris (formed by the 2 heads of the muscle)

Question 59

What are the symptoms of cubital tunnel syndrome??

Answer 59

Compression of the ulnar nerve in the cubital tunnel results in Paraesthesia in the cutaneous territory of the ulnar nerve. It may also result in weakness in the muscles supplied by the ulnar nerve

Question 60

What is the treatment for cubital tunnel syndrome?

Answer 60

treatment is to ‘decompress’ the nerve (i.e. surgically release it and transpose (move) it anterior to the medial epicondyle).

Question 61

How do you remember the Muscles of the anterior compartment of the forearm?

Answer 61

4 – 1 = 3
• 4 Superficial (position your thumb on the medial epicondyle and spread your fingers into the forearm to resemble the four superficial flexors using the rhyme: pass/fail/pass/fail)
Pronator teres / Flexor carpi radialis / Palmaris longus / Flexor carpi ulnaris
• 1 Middle Flexor digitorum superficialis
• 3 Deep Flexor digitorum profundus, Flexor pollicis longus, Pronator quadratus

Question 62

How do you remember the innervation to the muscles of the anterior forearm?

Answer 62

All muscles of the anterior forearm are supplied by the median nerve, with the exception of flexor carpi ulnaris and the ulnar half of flexor digitorum profundus.
These are supplied by the ulnar nerve.

Question 63

How do you remember the Contents of the cubital fossa (lateral to medial)?

Answer 63

“Really Need Beer To Be At My Nicest”
RN = Radial nerve
BT = Biceps tendon
BA = Brachial Artery
MN = median nerve

Question 64

How do you remember the muscles of the posterior forearm?

Answer 64

3 x 3 (+3)
• 3x muscles to the wrist: extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris
• 3x muscles to the fingers: extensor digitorum, extensor digiti minimi, extensor indicis
• 3x muscles to the thumb: abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis
+3: anconeus, supinator and brachioradialis

All innervated by the radial nerve