Common Conditions Of The Wrist

Question 1

What is a scaphoid fracture , what causes a scaphoid fracture , presentation and complications ?

Answer 1

1. Scaphoid fracture is the the break of the scaphoid bone in the wrist.
2. The cause is often a fall on the outstretched hand.
3. Present with pain at the base of the thumb with worse use of the hand. Anatomical snuff box tender.
4. Complications could be avascular necrosis because blood supply to the scaphoid is mainly retrograde from the distal to the proximal pole. And since the blood supply to the proximal pole is tenuous , fractures through the waist of the scaphoid can result in avascular necrosis. This could lead to non-union ( fracture does not heal). This increases risk of osteoporosis.

Question 2

What is a colles fracture ?

Answer 2

1. Extra-articular fracture of the distal radius with dorsal angulation of the distal radius.

Cause : fall on outstretched hand with a pronated forearm and wrist in dorsiflexion. Predominantly elderly women or young adults. Risk factor is osteoporosis , thus more frequently seen in post menopausal women. Sometimes involved with high impact trauma eg skiing.

Presentation : pain , bruising , swelling , dinner fork deformity

Question 3

What is a smiths fracture ?

Answer 3

1. Extra articular fracture of the distal radius with palmar angulation of distal fragment.
2. Cause if falling into wrist whilst flexed or fall onto the Dorsum. Rare , less than 3%. More common in young males and elderly females.
3. Presentation , pain , bruising , garden spade defomority.

Question 4

What is rheumatoid arthritis? And what joints does it mainly affect

Answer 4

1. An autoimmune disease in which autoantibodies known as rheumatoid factor attack the synovial membrane. The inflamed synovial cells proliferate which forms a Pannus. This penetrates through cartilage and adjacent bone leading to joint erosion and deformity.
2. Mainly affects the metacarpophalangeal joints and proximal interphalangeal joints of the hands and feet. And the cervical spine.

Question 5

Why is rheumatoid arthiris usuallyhard to diagnose in a swollen hand ?

Answer 5

Because it is ‘ symmetrical polyarthiris’

Meaning that it affects multiple joints in symmetrical distribution , so you cannot compare the swollen hand to a normal hand because there is normal hand.

Question 6

Patients with rheumatoid arthritis in PIPJ and MCPJ usually present with what symptoms ?

Answer 6

1. Pain and swelling
2. Redness overlying the joints
3. Carpal tunnel syndrome.
4. Fatigue and flu like symptoms.

Question 7

In an x-ray , what are you likely to find in someone with RA ?

Answer 7

Joint space narrowing

2. Soft tissue shadow , which indicates soft tissue swelling.
3. Periarticular osteopenia

Question 8

What are the two most common deformities seen in patients with advanced RA ?

Answer 8

1. Swan neck deformity

2. Boutonnière deformity

Question 9

What is swan neck defomormity ?

Answer 9

This is where the PIPJ hyperextends and the MCPJ and DIPJ are flexed.

Question 10

What is boutonnières deformity ?

Answer 10

MCPJ and distal interphalangeal joint are hyperextended and the PIPJ is flexed.

Question 11

What is psoriatic arthropathy?

Answer 11

Psoriasis is a skin condition that causes red , flatly patches of skin covered in silver scales.

Only a minority of patients with psoriasis will develop arthritis. When it does develop , it is usually asymmetrical oligoartthiris where it develops in one joint at a time.

Unlike RA ( which normally affects PIPJS and MCPJS) , PA most commonly affects DIPJS. 80% of patients also have nail lesions such as pitting and onycholysis ( separation of nail from nail bed)

Question 12

What joint in the hand is most commonly affected by osteoarthritis?

Answer 12

The first carpometacarpal joint ( between the trapezium and the first metacarpal). This is more common in women than men.

The patient complains of pain at the base of the thumb , the pain is exacerbated by movement and relieved at rest. Stiffness increases following periods of rest. Can also lead to squaring of the hand due to first metacarpal subluxes in the ulnar direction.

Question 13

What is heberdens nodes ?

Answer 13

A very classic sign of osteoarthritis and affects the DIPJ of the fingers. More commonly affect women than men.

Initially , the patient develops cystic swelling containing gelatinous hyaluroic acid on the dorsolateral aspect of their DIP joint. The initial inflammation and pain subside and the patient is left with an osteophyte.

Question 14

When the same process of formation of heberdens nodes occurs in the proximal interphalangeal joint occurs , what is it called ?

Answer 14

Bouchard nodes

Question 15

What is carpal tunnel syndrome ?

Answer 15

Compression of the median nerve as it passes through the carpal tunnel from the forearm into the hand. It is the most common site of nerve entrapment in the body.

Question 16

What are risk factors for carpal tunnel syndrome ?

Answer 16

Obesity

Repetitive wrist work

Pregnancy

RA

Hypothyroidism

Question 17

What will a patient complain of in carpal tunnel syndrome ?

Answer 17

1. Paraesthesia in the distribution of the median nerve ( thumb , index finger , middle finger and radial half of the ring finger ). Symptoms are worst at night when the wrist drifts into flexion during sleep , narrowing the carpal tunnel further.
2. Long standing carpal tunnel syndrome can result in muscle weakness and atrophy of thenar muscles ( OAF - opponens polices , abductor pollicis brevis and flexor pollicis brevis ( superficial head).The patient will still be able to flex their thumb though as the deep head of the flexor pollicis brevis is innervated by the ulnar nerve and adduction of the thumb is spared as adductor pollicis is supplied by ulnar nerve.
3. Importantly , the palm is usually spared as the palmar cutaneous branch does not travel through the carpal tunnel.

Question 18

What is ulnar nerve compression in guyons canal ?

Answer 18

Also known as ulnar ulnar tunnnel syndrome .or handlebar palsy.This is where the ulnar nerve gets compressed in Guyons canal.

Question 19

Someone with ulnar tunnel syndrome , what will they present with ?

Answer 19

Patient will report with paraesthesia in the ring and little fingers , progressing to weakness of the intrinsic muscles of the hand supplied by the ulnar nerve ( adductor pollicis , palma and dorsal interrossi , lumbircals to ring and little fingers and deep head of flexor pollicis brevis )

Question 20

What is Dupuytrens contracture?

Answer 20

This is where there is localised thickening and contracture of the palmar aponeurosis leading to a flexion deformity of adjacent fingers.

Initially , the patient notices a thickening or nodule in their palm which can be painful , later in the disease process the myofibroblasts within the nodule contract leading to the formation of tight bands called cords in the palmar fascia.

The fingers eventually become stuck in the flexed position.

It is more common in males and in persons of Northern European origin.

Inheritance is autosomal dominant.

Digits most commonly affected are the ring and little fingers

Question 21

What conditions increase the risk of Dupuytren’s contracture ?

Answer 21

Type 1 diabetes

Smoking

Heart disease

Hypo/hyperthryoidism

HIV

epilepsy medications such as phenytoin

Question 22

How to test for carpal tunnel syndrome ?

Answer 22

1. Tunnel-s sign : tapping the nerve in the carpal tunnel to elicit pain in median nerve disturbution
2. Phalen-s manoeuvre : holding wrist in flexion for 60s will elicit numbness / pain in median nerve.

Question 23

What are the sensory affects of damage to the median nerve at the elbow , eg through a supra condylar fracture of the humerus ?

Answer 23

Lack of sensation over the areas that the median nerve innervates eg the thumb , index finger , middle finger and half of the ring finger.

Question 24

What are the motor effects of damage to the median nerve at the elbow ?

Answer 24

1. All flexors and pronators in the forearm will be paralysed. With the exception of the flexor carpi ulnaris ( because it is innervated by the ulnar nerve ) and the ulnar half of the flexor digitorium profundus.
2. The forearm is constantly supinated.
3. Wrist flexion is weak.
4. Flexion at the thumb is also prevented as both the flexor pollicis longus and brevis muscles are paralysed.
5. The lateral two lumbricals are affected and the patient will not be able to flex at the MCP joints or extend at the IP joints of the index and middle fingers.

Question 25

What are characteristic signs of damage to the median nerve above the elbow ?

Answer 25

1. The thenar eminence is wasted due to atrophy of the thenar muscles.
2. If a patient tries to make a fists, only the little and ring fingers can flex completely as flexor digotirum profundus is still intact and the lumbricals are still intact for these digits. This results in a characteristic shape of the hand , known as hand of benediction. However , in long standing lesions an Ape deformity may develop at REST.

Question 26

What is hand of benediction?

Answer 26

This is when the patient is asked to make a fist and only the little finger and ring finger are able to flex. And the thumb , index finger and middle finger remain fully extended.

Question 27

What sensory loss would a patient experience if they have damage to the median nerve in the wrist ? For example due to lacerations ( tears ) in the flexor retinaculum.

Answer 27

Thumb , index finger , middle finger and half of the ring finger will have sensory loss

Question 28

What motor function loss would a patient experience if they damaged the median nerve at their wrist ?

Answer 28

1. The muscles that will be paralysed are therefore LOAF :

L = lumbricals to the index and middle fingers

O = opponens pollicis

A = abductor pollicis brevis

F = flexor pollicis brevis ( superficial head )

Question 29

What sensory loss would patient experience if they had damaged their ulnar nerve at the elbow ? For example a medial epicodnylar fracture or by compression of the cubital tunnel

Answer 29

Little finger and half the ring finger will lose sensations on palmar surface and distal phalanges only.

Question 30

What motor loss would someone with damage to ulnar nerve at the elbow experience ?

Answer 30

1. Paralysis of flexor carpi ulnaris and the ulnar half of the flexor digitorium profundus.
2. The ulnar nerve supplies the hypothenar eminence muscles known as : adductor pollicis , the deep head of the flexor pollicis brevis , the interossei , the lumbricals fo the ring and little finger , palmaris brevis. These muscles will be paralysed.

Question 31

What will someone present with - if they have damage to their ulnar nerve at the elbow ?

Answer 31

On RELAXATION , patient will present with a less pronounced ‘claw’hand. The fingers are hyperextended at the metacarpophalengeal joint and flexion at the proximal interphalangeal joint. The 4th and 5th digits are unable to move due to the hypothenar muscles and 2 medial lumbrical muscles being paralysed.

Adduction and abduction of fingers cannot occur due to paralysis of the interossei.

Adduction of the thumb is impaired because of paralysis of the adductor pollicis. Will have a positive Fromen-s sign.

Question 32

Ulnar nerve injury at the wrist I caused by what mechanisms ?

Answer 32

Lacerations of the anterior wrist

Question 33

What motor functions will be impaired in someone with a ulnar nerve injury at the wrist?

Answer 33

The muscles of the hypothenar eminence such as the adductor pollicis , the deep head of flexor pollicis brevis , the interossei, the lumbricals to the ring and little finger and palmar brevis will be paralysed.

The forearm muscles , however will still be in tact. For example the flexor digitorium profundus will still be intact.

A person will be presented with a ‘ claw’ hand. Where the MCP joint will be hyperextended and the P/DIP joints will be flexed AT REST.

Question 34

What is the ulnar paradox ?

Answer 34

• usually you would expect a more proximal injury to produce a more pronounced deformity. However , the opposite occurs.

For example , damage to the ulnar nerve at the elbow will cause a less pronounced ‘ claw’ hand than if someone was to damage their ulnar nerve at their wrist. This is because , if the ulnar nerve is damaged at the elbow then Flexor digitorium Profundus will be paralysed which means flexion of the distal interphalangeal joint will not occur of the ring and little finger. Therefore , with ulnar nerve damage that occurs in the elbow - there will only be hyperextension of the MCPJ and flexion at the proximal IPJ.

Question 35

Why are the MCPJS of the ring and little fingers hyperextended and the IPJS flexed in ulnar nerve damage ?

Answer 35

The lumbrical muscles flex the digits at the MCPJ usually in a healthy individual , whereas the extend the joints at the IPJ via the Dorsal extensor expansion.

In an ulnar claw , the MCPJS are hyperextended due to unopposed extension from the extensor digitorium in thr posterior compartment of the forearm. And the proximal and distal IP joints are flexed due to unopposed flexion from the long flexor muscles ( FDS AND FDP).

Question 36

Mnemonic to remember the muscles innervated by the median nerve in the hand

Answer 36

Lumbricals ( 1st and 2nd)

Opponens pollicis

A bductor pollicis brevis

F - flexor pollicis brevis ( superficial head )

Question 37

Actions of the lumbricals

Answer 37

Flex MCPJ

extend the IPJ

Question 38

Mnemonic to remember th muscles of the thenar eminences

Answer 38

O - opponens pollicis

A - Abductor pollicis brevis

F - flexor pollicis brevis

Question 39

Mnemonic to remember the muscles present in the hypothenar eminences

Answer 39

O - opponens digiti minimi

A - Abductor digiti minimi

F - flexor digiti minimi