Session 9: Common Conditions of the Hand and Wrist Flashcards
What is this? (Most common fracture of the carpal bones - 70-80%)
Scaphoid fracture.
Mechanism of injury of scaphoid fracture.
Most common amongst adolescents and young adults.
Usually fall onto an outstretched hand (FOOSH) which results in hyperextension and impaction of the scaphoid against the ri on the radius.
Clinical presentation of scaphoid fractures.
Pain in the anatomical snuffbox
Pain is exacerbated by moving the wrist.
Passive range of motion is reduced.
Swelling around the radial and posterior aspects of the wrist.
Why is delayed diagnosis of scaphoid fractures common?
Because x-rays taken immediately after the injury may not reveal the scaphoid fracture.
This means that if the initial x-ray do not show any fracture it is important to do a follow-up x-ray after 10-14 days.
In the meantime it is treated as a scaphoid fracture.
Why is it important to catch a scaphoid fracture?
Because of the mainly retrograde blood supply** of the scaphoid bone. The blood supply to the proximal pole is tenuous which means that if there is a fracture through the waist of the scaphoid it can lead to **avascular necrosis.
Complications of scaphoid fractures that have not been treated.
High risk of non-union, malunion and avascular necrosis.
Late complications include carpal instability and secondary OA.
What is Colle’s fracture?
An extra-articular fracture of the distal radial metaphysis with dorsal angulation and impaction meaning the metaphysis will be angulated dorsally.
In which people are Colle’s fracture most common?
In patients with osteoporosis so e.g. post-menopausal women.
Mechanism of injury of Colle’s fracture.
Fall onto an outstretched hand with a pronated forearm and wrist in dorsiflexion.
In young people it can be due to high impact trauma like skiing.
Clinical presentation of Colle’s fracture.
Painfule, deformed and swollen wrist.
Treatment of Colle’s fracture.
Treated by reduction and immobilisation in a cast.
Complications of Colle’s fracture.
Malunion resulting in dinner-fork deformity.
Median nerve palsy and post-traumatic carpal tunnel syndrome.
Secondary OA
Tear of the extensor pollicis longus tendon.
What is this?
Smith fracture
What is Smith fracture?
Fracture of distal radius with palmar angulation of the distal fracture fragment. (Reverse Colle’s fracture)
Mechanism of injury of Smith fracture.
Common in young males and elderly females.
Fall onto a flexed wrist or a direct blow to the back of the wrist.
Complications of Smith fracture.
Malunion
Residual volar displacement of the distal radius results in a cosmetic deformity referred to as a garden spade.
Garden spade deformity and distorts the carpal tunnel and can result in carpal tunnel syndrome.
What is rheumatoid arthritis?
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.
Where in the hand are you most likely to find rheumatoid arthritis?
Particularly affect the MCPJ and the PIPJ.
Why might RA of the hands be hard to diagnose if there is only mild swelling?
Because it is symmetrical meaning it affects multiple joints and usually both hands at the same time.
So if there is mild swelling it can be hard to see if it is a swelling or not because there is no normal hand to make a comparison with.
Clinical presentation of rheumatoid arthritis of the hands.
Pain and swelling of the PIPJs and MCPJs of the fingers.
Erythema overlying the joints.
Stifness worst in the morning and after periods of inactivity.
Carpal tunnel syndrome
Fatigue and flu-like symptoms.
Rheumatoid nodules in the fingers and over the elbow.
X-ray features of rheumatoid arthritis.
Joint space narrowing
Periarticular osteopenia/osteoporosis
Juxta-articular bone erosions
Subluxation and gross deformity
Soft tissue swelling
What are the two most common deformities of advanced rheumatoid arthritis?
Swan neck deformity
Boutonniere deformity
What is swan neck deformity?
(What joints are flexed/extended)
Occurs when the PIPJ hyperextends and the MCPJ and DIPJ are flexed.
Why does swan neck deformity occur?
The tissues on the palmar aspect of the PIPJs become lax as a result of adjacent synovitis.
Imblanace between the muscle forces acting on the PIPJs so the joint with its lax tissues on the palmar surface becomes hyperextended.
At the DIPJs there is either elongation or rupture of the insertion of extensor digitorum into the base of the proximal phalanx, resulting in mallet deformity. This means that the DIPJs cannot extend properly and become flexed.
What is Boutonniere deformity?
(What joints are flexed/extended)
MCPJs are hyperextended as well as the DIPJs.
PIPJs are flexed.
Why does Boutonniere deformity occur?
Inflammation in PIPJs leads to lengthening or rupture of the central slip of extensor digitorum at its insertion into the base of the middle phalanx on the dorsal surface. This means that PIPJs will be flexed.
The lateral bands slip down the side of the finger so that they re on the palmar surface at the level of the PIPJ and insteadof acting as extensors of the PIPJ it will start to act as flexors as well as hyperextending DIPJ.
What is this?
Psoriatic arthropathy
What is psoriasis?
A skin condition that causes red, flaky patches of skin covered with silvery scales.
Occur on elbows, knees, scalp and lower back.
Clinical presentation of PA.
Arthritis in DIPJs.
Nail lesions such as pitting and onycholysis. (Onycholysis can also occur in hyperthyroidism and fungal nail infections but the pitting is very typical to PA).
What are Bouchard’s nodes?
Sign of OA that affect the PIPJs instead of DIPJs.
Same principle as Heberden’s nodes.
What is this?
Dupuytren’s contracture.
What will be the sensory impairment in a radial nerve injury in the spiral groove.
Posterior cutaneous nerve of the arm branches from the radial nerve above the spiral groove so it remains unaffected.
The lower lateral cutaneous nerve of the arm and posterior cutaneous nerve of the forearm branch high in the spiral groove so are usually unaffected.
The paraesthesia is therefore usually in the distribution of the superficial branch of the radial nerve. (Radial dorsal surface of the hand, dorsal surface of the thumb, index, middle and radial half of the ring finger, except for the tips of these fingers.)
Explain the movements of the hand and wrist and muscles involved in high median injury.
Both the pronators (pronator teres and pronator quadratus) will be paralysed meaning that the forearm will be supinated due to unopposed action of biceps and supinator.
Flexion of the wrist is weak and often accompanied by adduction because of the pull of flexor carpi ulnaris.(Flexor carpi radialis, palmaris longus, flexor digitorum superficialis and radial half of flexor digitorum profundus are paralysed so flexion is weak).
Flexion of the thumb will be weak as flexor pollicis longus and the intrinsic thenar muscles will be paralysed. (Remember LOAF). Abductor pollicis brevis, opponens pollicis, flexor pollicis brevis will be paralysed. So opposition and palmar abduction will be absent (radial abduction still present due to abductor pollicis longus from radial nerve).
FDS will be paralysed and FDP will be paralysed at index and middle fingers. Two radial lumbricals will make index and middle fingers paralysed as well but small flexion at MCPJ is possible due to interossei.
Thumb will be extended at IPJ and MCPJ however the thumb can still be flexed at MCPJ due to deep head of flexor pollicis brevis.
What is hand of benediction?
The patient is asked to make a fist.
In hand of benediction and a high median nerve injury the patient will flex little and ring finger but will be unable to flex index and middle finger.
How will low median nerve injuries present (aka median nerve injuries at the wrist)?
This can be very similar to carpal tunnel syndrome.
The anterior compartment of the forearm will be spared. This means that pronation will work (pronator teres and quadratus).
Flexor carpi radialis, palmaris longus, FDP and FDS will all be intact. Flexion of the wrist will work and flexion of the fingers as well. Flexor pollicis longus is also intact meaning flexion at the IPJ of the thumb will work.
Palmar cutaenous branch of the median nerve will be spared meaning which supply sensation of the thenar eminence.
Muscles that will be paralysed is: LOAF
Two radial Lumbricals
Opponens pollicis
Abductor pollicis brevis
Superficial head of flexor pollicis brevis
This means that opposition and palmar abduction will not work.
This will lead to ape hand deformity where the thenar eminence has atrophied and the thumb is adducted and externally rotated.
Why are the MCPJs of the ring and little fingers hyperextended in ulnar claw?
The 3rd and 4th lumbricals are supplied by the ulnar nerve and are paralysed. This means that flexion will be weakened. The lumbricals flex at MCPJ and extend at the IPJs.
So in ulnar claw flexion at MCPJ will be weakened at extension at IPJs will be weakened.
This means that the opposing muscles like FDP and FDS, and extensor digitorum will flex at IPJs and extend at MCPJ respectively.
Sensory loss in injury to the ulnar nerve at the elbow.
Palmar ulnar surface of the hand.
Dorsal ulnar surface of the hand.
One and a half ulnar digits aka little finger and ulnar half of ring finger.
