Disorders of the elbow

Question 1

What is the most common mechanism of a supracondylar fracture of the distal humerus?

Answer 1

The most common mechanism is falling from a moderate height onto an outstretched (FOOSH) hand with the elbow hyperextended e.g. a child falling off ‘monkey bars’.

Question 2

Who are supracondylar fractures most common in?

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 will a child with a supraacondylar fracture present with?

Answer 3

Pain, deformity and loss of function

Question 4

What way the distal fragment usually displaced in a supracondylar fracture?

Answer 4

Posteriorly

Question 5

What are the three main complications of a supracondylar fracture?

Answer 5

• Malunion
• Damage to the median nerve, radial nerve or ulnar nerve
• Ischaemic contracture

Question 6

What will malunion of a supracondylar fracture result in?

Answer 6

Cubitus varus

Question 7

What is ischaemic contracture?

Answer 7

The brachial artery passes very close to the fracture site and can occasionally be damaged or occluded by a displaced fracture. 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 in 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 8

What does the wrist look like in a Volkmann’s ischaemic contracture?

Answer 8

The 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 9

What should be done if there is any compromise of the neurovascular supply of the forearm or hand?

Answer 9

Emergency reduction and fixation of the fracture

Question 10

What is the most common mechanism of an elbow dislocation?

Answer 10

Elbow dislocation usually occurs when a person, often a child, falls on their
outstretched hand (FOOSH) with the elbow partially flexed.

Question 11

Why are elbow dislocations more common in the mid-flexion position?

Answer 11

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 12

What way does the elbow dislocate most commonly?

Answer 12

Over 90% of elbow dislocations are posterior (distal fragment). The distal end of the humerus is driven through the joint capsule anteriorly.

Question 13

Which ligament is usually torn in an elbow dislocation?

Answer 13

The ulnar collateral ligament is usually torn and there can also be an associated fracture and/or ulnar nerve involvement.

Question 14

How might an anterior elbow dislocation occur?

Answer 14

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 15

What is a pulled elbow?

Answer 15

Sublaxation of the radial head

Question 16

Who are pulled elbows most common in?

Answer 16

This injury 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 17

What is the classically described mechanism of a pulled elbow?

Answer 17

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).
Remainder of cases occur during falls or over-reaching for an object.

Question 18

Why does a pulled elbow most commonly occur in pronation?

Answer 18

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

Question 19

What are the most common type of elbow fractures in adults?

Answer 19

Radial head and neck fractures

Question 20

How do radial head and neck fractures occur?

Answer 20

They usually result from a fall on an outstretched hand (FOOSH) when the radial
head impacts on the capitulum of the humerus.

Question 21

How does a patient with a radial head and neck fracture present?

Answer 21

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 22

What is the main X-ray sign of a radial head and neck fracture?

Answer 22

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. 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.

Question 23

Who is OA of the elbow most common in?

Answer 23

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 24

How does OA of the elbow present?

Answer 24

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 25

What is rheumatoid arthritis?

Answer 25

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.

Question 26

What does rheumatoid arthritis affect?

Answer 26

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 27

What are the X-ray features of rheumatoid arthritis?

Answer 27

Loss of joint space Erosions of bone (marginal) Soft tissue swelling See through bones (periarticular osteopenia)

Question 28

How is rheumatoid arthritis of the elbow treated?

Answer 28

Rheumatoid arthritis is 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. This is a total elbow replacement.

Question 29

How does lateral elbow tendinopathy (tennis elbow) present?

Answer 29

It presents with pain at the site of the common extensor origin at the lateral epicondyle. 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 30

When will the patient experience pain in lateral elbow tendinopathy?

Answer 30

The patient will typically experience pain over the lateral epicondyle during extension of the wrist, especially if this is against resistance.

Question 31

How is lateral elbow tendinopathy treated?

Answer 31

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 32

What is the common site of pathology of medial elbow tendinopathy?

Answer 32

The most common site of pathology is the interface between the pronator teres and the flexor carpi radialis (FCR) origins

Question 33

What movements/sports is medial elbow tendinopathy associated with?

Answer 33

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 34

How do patients with medial elbow tendinopathy present?

Answer 34

Patients present with an aching pain over the medial elbow, often noticed during the acceleration phase of throwing. Pain is produced on resisted flexion or pronation of the wrist. Ulnar nerve symptoms are present in up to 20% of cases due to the proximity of the ulnar nerve to the medial epicondyle.

Question 35

What are the three common causes of swelling around the elbow?

Answer 35

* Olecranon bursitis * Rheumatoid nodules * Gouty tophi

Question 36

How does olecranon bursitis occur?

Answer 36

It is usually due to 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. The swelling is soft, cystic (fluid-filled) and transilluminates (light can be shined through it).

Question 37

How is olecranon bursitis treated?

Answer 37

Patients usually present due to the cosmetic concern of the unsightly swelling. Treatment is conservative with compression bandaging +/- aspiration. A hydrocortisone injection is sometimes necessary in chronic cases. Sometimes the bursitis is a result of infection of the bursa (septic bursitis e.g. following a minor penetrating injury to the elbow), in which case aspiration, compression and antibiotics are required. Occasionally surgical drainage and washout under anaesthetic will be needed to resolve the infection.

Question 38

Who tend to develop rheumatic nodules?

Answer 38

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 39

Where do rheumatic nodules usually occur?

Answer 39

Rheumatoid nodules 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 non- tender although the overlying skin can occasionally ulcerate and become infected.

Question 40

How are rheumatic nodules treated?

Answer 40

Patients present due to cosmetic concerns and treatment is by improving medical control of the underlying rheumatoid disease, although the response of existing nodules to this is somewhat variable.

Question 41

How does gout occur?

Answer 41

Gout is an inflammatory condition caused by hyperuricaemia. Around 90% of people with hyperuricaemia have difficulty excreting urate (the majority of which occurs in the kidneys) and the other 10% produce too much urate. 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 42

How should gout be treated?

Answer 42

Gout should be treated medically with non-steroidal anti-inflammatory drugs during the acute phase. Once the acute attack of gout has resolved, xanthine oxidase inhibitors such as allopurinol (a purine analogue) or febuxostat can then be prescribed to reduce the production of uric acid and reduce the risk of further attacks.

Question 43

What are tophi?

Answer 43

Tophi are nodular masses of monosodium urate crystals deposited in the soft tissues. They are a late complication of hyperuricaemia and develop in >50% of patients with untreated gout. They are usually painless, but complications can include pain, soft tissue damage and deformity, joint destruction and nerve compression.

Question 44

What are the most common sites of gout tophi?

Answer 44

The most 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 45

What is cubital tunnel syndrome?

Answer 45

Ulnar nerve compression

Question 46

How does cubital tunnel syndrome occur?

Answer 46

Minor trauma to the ulnar nerve in the cubital tunnel (e.g. banging your elbow on the desk) causes a sharp transient pain radiating from the elbow to the cutaneous ulnar nerve territory. People often refer to this as ‘catching their funny bone’ (humerus → humorous → funny bone)

Question 47

What does compression of the ulnar nerve in the cubital tunnel result in?

Answer 47

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.