Hand Flashcards
Briefly discuss nerve supply to the hand and testing of major nerves
Test radial function via extension of wrist Test ulna function for adduction of lumbricals Test medial nerve fucntion ok sign – recurrent median nerve passes over the flexar retinaculum and is therefore at risk of injury in cuts to the wrist n
Discuss dermatome distribution of the upper limb
a
Discuss nerve supply to the hand
Discuss subungual haemtoma and management
Nail bed compression may lead to local haemorrhage contained between the nail folds and nail
Need to assess DIP extensor tendon function and x-ray should be obtained to exclude unstable finger tip
Trephination reduces pain but does not hasten healing or alter infection risk
- heat
- 18 gauge needle twirling to drill through nail
Traumatic subungual haematomas with nail disruptions or skin fold laceration may have concurrent eponychial lacerations
Haematomas involving more than half the nail size have a 60% of nail bed injury increasing to 95% if there is a distal phalanx fracture. When nail and nail margins are intact there is no difference in outcomes between trephenation and removal of nail and nail bed repair. If nail is damaged or nail edges are broken need to remove nail and repair bed.
Discuss anatomy of finger tip and nail bed
Discuss repair of nail bed lacerations
Repair of nail bed laceration is controversial. Nail removal and repair of the eponychium is unessary except with significant disruption fo the nail and skin folds.
Primary repair using 5-0 or 6-0 absorbable sutures minimizes subsequent nail deformity and reduces fucntional disbaility
Nail bed avulsions may results in clevage of eponychium from the bed onto the nail. Small defects <25% may still heal however best practise is to secure the nail onto the original avulsion site.
DIsucss distal phalanx fracutres
Most common fracutres of the hand and are commonly associated with nail bed injruies
Fractures may be tuft, shaft or base. Base fracutres are most commonly caused by tendon avulsion and should promot investigation into active movement.
Tuft fracutres heal without incident. Most distal phalanx fractures are stable and can be treated conservatively– splinting for 2-3 weeks leaving the DIP free to ROM
Avulsion fractures should be splinted however should be discussed with hand specialist as often require repair. Mallet finger is the term applied to extensor avulsion fractues.
Discuss seymour type metaphyseal fracture
Fracutre between the insertion of the etensor tendon insertion dorsally and FDP tendon insertion volarly. More common in paediatric population where the physeal region may be weaker then the tendon insertion. There is no tendeon injury but this fracture causes an imbalance between the flexor and extensor forces leading to flexion defomrity at the level of the DIP
Discuss middle and proximal phalangeal fracutres
Two important tendon insertion sites occur at the middle phalanx
- FDS – which divides and inserts along much of the volar surface of the phalanx
- extensor tendon – which inserts on the proximal portion of the dorsal base
fracture at the neck will lead to volar angulation whereas fractures of the base usually result in dorsal angulation
Proximal phalangeal fractures generally have volar angulation due to extensor and interosseus muscle fucntion
Discuss metacarpal fractures
Due to the need for functional mobility, the thumb, index and middle fingers have little tolerance for deformity as compared to the ring and little fingers.
The thumb index and middle fingers can accomadate 10-15 degrees of dorsal angulation compared to 40-45 for the fourth and 50-70 for the fifth. All digits handle handle rotational deformity poorly
4th and 5th metacarpal fractures may injure the ulna nerve cause intrinsic muscle weakness and digital numbness. Any supspcious wounds should be treated as a human bite.
Metacarpal neck is the most common fracture location and is cuased by direct impaction. Metacarapl shaft fracutres usually from axial trauma may be transverse
Discuss management of metacarpal fractures
Most stable non displaced fracutres consist of reduction and splinting in the intrinsic plus position with the wrist extended to 30 degrees, the MCP joint flexed at 90 degrees with the PIP and DIP joints ket in etension
Metacarpal base fractures commonly involve the cparal-metacarpal articulation, resulting in an intra-articular fracture of joint displacement. Thye tend to remain angulated and displaced despite closed reduction all should be referred
Shaft fractures can be reduced with a goal of less than 3mm of metacarpal shortening, less then 10 degrees od odrsal angulation for the ring and litte finger and elimination of rotation. Can use 90-90 reduction method
Metacrapal neck fractures again can be reduced and splited with similar goals as above.
Metacarpal head fractures may be intra-articular and comminuted with a high risk of fracture displacement and malrotation. Intrtinsic plus cast + immediate referral
Discuss metacarpal fractures of the thumb
Due to the mobility of the thumb fractures in this digit are less common.
Extra-articular fractures are more common and are generally due to dircect trauma or impaction. They may be transverse, oblique and epiphyesial
Transverse fracutres are generally stable. Fracutre of more than 30 degrees angulation should undergo closed reduction and thumb spica immobilisation. Oblique fracture are generally unstable and require ortho for open reduction.
Discuss intra-articular metacarpal thumb fractures
Two intraritcular fracture of the thumb are the Bennet and Rolando
Bennett fracture involves an intra-articular metacarpal base fracture combined with disruption fo the first CMC ligaments leading to dislocation or subluxation of the distal metacarpal fracture. Management includes reduction of the fracture dislocation and immoblisation in a thumb spica
In a rolando fracture the thumb metacarpal is comminute. Difficult to see the classic finding is a y or t shapped pattent – needs hand service follow-up
Discuss the 90-90 method for metacarpal reduction
involves flexing the patient’s MCP and PIP 90 degrees. Dorsal force is applied to metacarpal head by through dorsal pressure on the proximal phalanx. The 90-90 positioning also stretches the collateral ligaments of the MCP joint, which further optimizes the reduction technique.
Discuss the intrinsic plus position
wrist extended 30 degrees, MCP joint flexed 90 degrees and both PIP and DIP joints kept in extension. used for most metacarpal fractures
Discuss distal interphalangeal joint injury
Colateral and volar ligaments as well as flexor and extensor tendons stabilize the DIP joint as such dislocation at this joint are rare. They are often associated with open injuries
Avulsion fractures, volar plate tears or tendon entrapment may prevent reduction and require operative treatment.
Discuss zone 1 injuries to the extensor tendons
includes the conjoined extensor tendon over the DIP and its insertion at the dorsal distal phalanx. Complete transection of the tendon causes an unopposed flexure posture at the DIP joint.
Mallett fingers are caused by forced flexion of the extended finger and a commonly assoicated with avulsion fractures. Closed injuries benifit from early immobilization in extension and improved with 6-8 weeks. Chronic untreated mallett finger can result in swan neck deformities from dorsally displaced lateral bands.
