Trauma and orthopaedics (5): The elbow

Question 1

osteology of the humerus

Answer 1

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The long bone of the upper arm

• Extends from the shoulder to the elbow
• Proximal aspect articulates with the glenoid fossa of the scapula- glenohumeral joint
• Distally, at the elbow joint, the humerus articulates with the head of the radius and trochlear notch of the ulnar

Question 2

elbow joint

Answer 2

• Hinge-type synovial joint

2 separate articulations:

• Trochlear notch of the ulna and the trochlea of the humerus
• Head of the radius and the capitulum of the humerus

Question 3

joint capsule of elbow

Answer 3

Like all synovial joints, the elbow joint has a capsule enclosing the joint

• Strong and fibrous- strengthening the joint
• Thickened medially and laterally to form collateral ligaments- stabilise the flexing and extending motion of the arm

Question 4

bursae of the elbow

Answer 4

• Membranous sac filled with synovial fluid
• Acts as a cushion to reduce friction between the moving parts of a joint, limiting degenerative damage.
• Key bursae of the elbow
  
  • Intratendinous- located within the tendon of the triceps brachii
  • Subtendinous- between the olecranon and the tendon of the triceos brachii, reducing friction between the two structures during extension and flexion of the arm
  • Subcutaneous (olecranon) bursa- between the olecranon and the overlying connective tissue

Question 5

ligaments of the elbow

Answer 5

Joint capsule of the elbow is strengthened by ligaments medially and laterally.

• Radial collateral ligament (lateral)
  
  • Extends from the lateral epicondyle, blending with the annular ligament of the radius
• Ulnar collateral ligament (medial) originates from the medial epicondyle and attaches to the coronoid process and olecranon of the ulnar

Question 6

arterial supply of the elbow joint

Answer 6

supply to the elbow joint is from the cubital anastomosis, which includes recurrent and collateral branches from the brachial and deep brachial arteries.

Question 7

nervous supply of the elbow

Answer 7

Its nerve supply is provided by the median, musculocutaneous and radial nerves anteriorly, and the ulnar nerve posteriorly.

Question 8

Movement of the elbow

Answer 8

Orientation of the bone forming the elbow joint produces a hinge type synovial joint- allows for extension and flexion of the forearm

• Extension- triceps brachii and anconeus
• Flexion- brachialis, biceps brachii, brachioradialis
  *

Question 9

the upper arm contains 4 muscle

Answer 9

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• 3 in the anterior compartment (biceps brachii, brachialis, coracobrachialis)
• 1 in the posterior compartment (triceps brachii)

All innervated by the musculocutaneous nerve. Good way to remember: BBC- Biceps, Brachialis, coracobrachialis. Arterial supply- muscular branches of the brachial artery.

Question 10

areas of the elbow

Answer 10

cubital fossa

Question 11

cubital fossa

Answer 11

An area of transition between the anatomical arm and the forearm- located as a depression the anterior surface of the elbow joint.

Question 12

borders of the cubital fossa

Answer 12

Triangular shape:

• Lateral border- medial border of the brachioradialis
• Medial border- lateral border of the pronator teres muscle
• Superior border- hypothetical line between the epicondyles of the humerus
• Floor- formed proximally by the brachialis and distally by the supinator muscle
• Roof- skin and fascia, reinforced by the bicipital aponeurosis
  
  • Within the floor runs the median cubital vein- accessed for venepuncture

Question 13

Olecranon bursitis

Answer 13

refers to inflammation and swelling of the bursa over the elbow. The olecranon is the bony lump at the elbow, which is part of the ulna bone.

Question 14

pathophysiology of bursitis

Answer 14

Bursitis is inflammation of a bursa. This causes thickening of the synovial membrane and increased fluid production, causing swelling.

This inflammation can be caused by a number of things:

• Friction from repetitive movements or leaning on the elbow
• Trauma
• Inflammatory conditions (e.g., rheumatoid arthritis or gout)
• Infection – referred to as septic bursitis

Question 15

olecranon bursitis also known as

Answer 15

“student’s elbow”, as students may lean on their elbow for prolonged periods while studying, resulting in friction and mild trauma leading to bursitis. It can also occur with people with occupations that require leaning on the elbow, such as plumbers or drivers.

Question 16

presentation of olecranon bursitis

Answer 16

The typical presentation is a young/middle-aged man with an elbow that is:

• Swollen
• Warm
• Tender
• Fluctuant (fluid-filled)

Question 17

It is important to identify where bursitis is caused by infection. Features of infection are:

Answer 17

• Hot to touch
• More tender
• Erythema spreading to the surrounding skin
• Fever
• Features of sepsis (e.g., tachycardia, hypotension and confusion)

Question 18

management of bursitis

Answer 18

• Rest
• Ice
• Compression
• Analgesia (e.g., paracetamol or NSAIDs)
• Protecting the elbow from pressure or trauma
• Aspiration of fluid may be used to relieve pressure
• Steroid injections may be used in problematic cases where infection has been excluded

Question 19

management when infection suspected or cannot be excluded

Answer 19

involves:

• Aspiration of the fluid for microscopy and culture
  
  • Pus indicates infection
  • Straw-coloured fluid indicates infection is less likely
  • Blood-stained fluid may indicate trauma, infection or inflammatory causes
  • Milky fluid indicates gout or pseudogout
• Antibiotics- fluxcloxacillin

Question 20

patients systemically unwell with infected bursa

Answer 20

Patients that are systemically unwell (e.g., immunocompromised or have sepsis) need admission to hospital for further management, including:

• Bloods (including lactate)
• Blood cultures
• IV antibiotics
• IV fluids

Question 21

olecranon process fracture RF

Answer 21

occur with a bimodal age distribution; occurring in the young following high energy injuries and in the elderly (more common) following low energy indirect injuries.

Question 22

olecranon osteology

Answer 22

The olecranon is the region of the proximal ulna from its tip to the coronoid process. It articulates with the trochlea of the distal humerus, and all olecranon fractures are therefore intra-articular fractures by definition

The olecranon is the site of insertion for the triceps muscles.

Question 23

cause of olecranon fracture

Answer 23

indirect trauma- FOOSH

• causes sudden pull of the triceps muscel

Question 24

presentation of olecranon fracture

Answer 24

• FOODH
• elbow pain
• swelling
• reduced mobility
• disruption to tricep means there is an inability to extent the elbow against gravity
• shoulder and wrist joint should also be examined

Question 25

investigations for olecranon fracture

Answer 25

* routine bloods- clotting and group and save * plain AP and lateral X-ray * joint and those above and below * olecranon will usually have a degree of displacement * CT for complex injury

Question 26

management of olecranon fractue

Answer 26

* ATLS * adequate analgesia * non op management * op management

Question 27

non -op management of olecranon fractue

Answer 27

is usually indicated for displacement \<2mm, with immobilisation in 60-90 degrees elbow flexion and early introduction of range of motion at 1-2 weeks * There is increasing use of non-operative management for all patients over 75, irrespective of displacement, as whilst the degree of extension may be lost, the functional outcome is often appropriate

Question 28

op management of olecranon fracture

Answer 28

is usually indicated for displacement \>2mm, requiring (depending on fracture configuration) techniques such as tension band wiring (if fracture proximal to the coranoid process) or olecranon plating (if at level of, or distal to, the coranoid process) may be used * There is a very high rate of removal of metalwork, as due to the very superficial nature of the injury, it often impacts the patient significantly

Question 29

radial head fractue is the

Answer 29

most common fracture of the elbow

Question 30

cause of radial head fracture

Answer 30

indirect trauma axial loading causes radial head to be pushed against the capitulum of the humerus- FOOSH This most commonly occurs with the arm in extension and pronation.

Question 31

presentation of radial head fracture

Answer 31

* FOOSH * pain and tenderness on palpation over lateral aspect of the low and radial head * pain on supination and pronation * swelling and bruising * shoulder and wrist joints should be examined

Question 32

investigations for radial head fractue

Answer 32

* **routine blood tests**, including a clotting screen and a Group and Save. * AP and lateral X-ray * + joint above and below * CT may be useful for more complex injiury and comminution

Question 33

radial head fracture easily missed on Xray

Answer 33

* may only see elbow effusion * on lateral projection known as ‘sail sign’ * shown as an elevation of anterior fat pad

Question 34

classification of radial head fracture

Answer 34

* **Mason Type 1** – Non-displaced or minimally displaced fracture (\<2mm). * **Mason Type 2** – Partial articular fracture with displacement \>2mm or angulation. * **Mason Type 3** – Comminuted fracture and displacement (a complete articular fracture).

Question 35

management of radial head fracture

Answer 35

* ATLS * analgesia * check for neurovascular compromise * definitive management guided by mason classification

Question 36

management of radial head fracture based on Mason classification

Answer 36

* **Mason type 1 injuries** – treated non-operatively, with a short period of immobilization with sling (less than 1 week) followed by early mobilisation * **Mason Type 2 injuries** – if no mechanical block then can be treated as per a type 1 injury, whilst if a mechanical block is present then these may need surgery (typically an open reduction internal fixation (ORIF)) * **Mason Type 3 injuries** – will nearly always warrant surgical intervention, either via ORIF or radial head excision or replacement (especially in highly comminuted fractures)