Disorders of the forearm and wrist

Question 1

Scaphoid Fracture account for how much of carpal bone fracture

Answer 1

Scaphoid fractures account for 70-80% of all carpal bone fractures.

Question 2

scaphoid fracture cause

Answer 2

They are caused by a fall onto an outstretched hand (FOOSH) and are most common in adolescents.

Question 3

presentation of scaphoid fracture

Answer 3

A scaphoid fracture presents with pain in the anatomical snuffbox (a region just below the base of the thumb) that is exacerbated by movement.

Question 4

complications of scaphoid fracture

Answer 4

Complications include a high risk of non-union and avascular necrosis due to the scaphoid bone having a retrograde blood supply (meaning if there is a fracture that disrupts blood supply, the bone may not heal).

Question 5

management of scaphoid fracture

Answer 5

The fracture may not show on the initial X-Ray, but the patient should be treated as if a fracture is present. Then a repeat X-Ray should be done 10-14 days later - the fracture should now be visible due to bone resorption along the fracture line. Treatment may or may not require surgery but a splint or cast is used to increase chances of union of the bone fragments.

Question 7

Colles’ Fracture

Answer 7

A Colles’ fracture is an extra-articular fracture of the distal radius with dorsal angulation and impaction (meaning if the fracture looked like this >, the larger end would be on the dorsal side).

Question 8

cause of colles fracture

Answer 8

It is caused by a FOOSH, with a pronated forearm and dorsiflexed wrist.

Question 9

presentation of colles fracture

Answer 9

This condition presents with pain, a ‘dinner fork’ deformity and swelling. An associated ulnar styloid process fracture is relatively common.

Question 10

colles fracture treatment

Answer 10

Treatment may include casting or surgery.

Question 12

Smiths’ Fracture

Answer 12

A Smiths’ fracture is an extra-articular fracture of the distal radius with volar/palmar angulation and impaction (meaning the open bit of the > shaped fracture is on the palmar side).

Question 13

cause of smiths fracture

Answer 13

It is caused by a fall onto a flexed wrist or a blow to the back of the wrist. This condition is relatively rare but usually occurs in young males or elderly females.

Question 14

smiths fracture presentation

Answer 14

It presents with pain, a ‘garden spade’ deformity and swelling.

Question 15

smiths fracture complication

Answer 15

Complications include malunion leading to permanent garden spade deformity, which can in turn lead to carpal tunnel syndrome.

Question 16

treatment of smiths fracture

Answer 16

Treatment may include casting, closed reduction or surgery.

Question 17

Carpal Tunnel Syndrome

Answer 17

Carpal tunnel syndrome is the compression of the median nerve as it passes through the carpal tunnel from the forearm into the hand.

Question 18

risk factors of carpal tunnel syndrome

Answer 18

Risk factors for this condition include: being female, obesity, pregnancy, rheumatoid arthritis and hypothyroidism. It can also present in those who frequently rest on the palmar side of the wrist e.g. when typing.

Question 19

presentation of carpal tunnel syndrome

Answer 19

It presents with paraesthesia in the palmar aspect of digits 1-3 and the lateral half of the 4th digit. There is weakness of abduction and opposition of the 1st digit.

Sensation to the palm is spared as the palmar cutaneous branch of the median nerve does not enter the carpal tunnel. Flexion/adduction of the 1st digit are also spared as the muscles that enact these movements have an ulnar nerve supply as well as a median nerve supply.

Question 20

management of carpal tunnel syndrome

Answer 20

Non-surgical treatment includes bracing/splinting and NSAIDS to reduce inflammation and manage pain, as well as avoiding or modifying harmful activities. If the symptoms are more severe, however, surgery followed by exercises to regain full movement is the usual treatment plan.

Question 21

Ulnar Nerve Compression in Guyon’s Canal

Answer 21

Ulnar nerve compression in Guyon’s canal is also known as ‘Handlebar palsy’ and is caused by the entrapment of the ulnar nerve as it passes laterally to pisiform over the flexor retinaculum.

This condition is relatively common in cyclists, hence the name ‘Handlebar palsy’.

Question 22

ulnar nerve compression guyons canal presentation

Answer 22

It presents with paraesthesia and weakness of flexion/extension of the 4th and 5th digits. There is also weakness of adduction of the 1st digit.

Question 23

treatment of ulnar nerve compression in guyons canal

Answer 23

Initial treatment is anti-inflammatory drugs or corticosteroid injections. If this is unsuccessful, surgery is used to reduce the compression on the ulnar nerve by relieving the tension on the volar carpal ligament (which forms the roof of Guyon’s canal).

Question 24

Low Median Nerve Injury

Answer 24

A low injury to the median nerve occurs due to a penetrating injury to the wrist.

Question 25

low median nerve injury presentation

Answer 25

It presents with an ‘Ape hand deformity’ – flattened thenar eminence and an adducted/externally rotated 1st digit due to paralysis of lumbricals and thenar muscles.

Sensation to the palm remains intact as the palmar cutaneous branch is usually spared.

Question 26

treatment of low median nerve injury

Answer 26

Treatment ranges from rest and avoiding aggravating activities to surgery as the severity increases. Treatment can also include corticosteroid injections, splinting and physical therapy.

Question 27

Low Ulnar Nerve Injury

Answer 27

A low injury to the ulnar nerve occurs due to a penetrating injury at the wrist.

Question 28

low ulnar nerve injury presentation

Answer 28

It presents with a ‘low ulnar claw’ – hyperextension at the metacarpophalangeal joints, and flexion at the interphalangeal joints of the 4th and 5th digits. There is also paraesthesia of the palmar aspects and the distal dorsal aspects of the 4th and 5th digits.

The sensation of the ulnar border of the hand will be spared.

Question 29

low ulnar nerve injury Treatment

Answer 29

ranges from rest and avoiding aggravating activities to surgery as the severity increases. Treatment can also include corticosteroid injections, splinting and physical therapy.

Question 30

It is important to differentiate this from the appearance of the hand in a high ulnar nerve injury

Answer 30

Unexpectedly, the appearance of the low ulnar claw is more severe than the appearance of the high ulnar claw. This is because with a high ulnar nerve injury, the innervation to flexor digitorum profundus is destroyed, meaning the fingers cannot flex as much as they can in a low ulnar nerve injury, when this muscle is spared. This is called the ‘Ulnar paradox’.