Hand

Question 1

Briefly discuss nerve supply to the hand and testing of major nerves

Answer 1

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

Question 2

Discuss dermatome distribution of the upper limb

Answer 2

a

Question 3

Discuss nerve supply to the hand

Answer 3

Question 4

Discuss subungual haemtoma and management

Answer 4

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.

Question 5

Discuss anatomy of finger tip and nail bed

Answer 5

Question 6

Discuss repair of nail bed lacerations

Answer 6

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.

Question 7

DIsucss distal phalanx fracutres

Answer 7

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.

Question 8

Discuss seymour type metaphyseal fracture

Answer 8

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

Question 9

Discuss middle and proximal phalangeal fracutres

Answer 9

Two important tendon insertion sites occur at the middle phalanx

1. FDS – which divides and inserts along much of the volar surface of the phalanx
2. 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

Question 10

Discuss metacarpal fractures

Answer 10

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

Question 11

Discuss management of metacarpal fractures

Answer 11

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

Question 12

Discuss metacarpal fractures of the thumb

Answer 12

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.

Question 13

Discuss intra-articular metacarpal thumb fractures

Answer 13

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

Question 14

Discuss the 90-90 method for metacarpal reduction

Answer 14

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.

Question 15

Discuss the intrinsic plus position

Answer 15

wrist extended 30 degrees, MCP joint flexed 90 degrees and both PIP and DIP joints kept in extension. used for most metacarpal fractures

Question 16

Discuss distal interphalangeal joint injury

Answer 16

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.

Question 17

Discuss PIP injuries

Answer 17

Most common joint dislocated in the hand. Dorsal dislocation without fracture caused by hyperextension are the most common form of dislocation.

Be aware of volar plate fracutres – avulsion fracture. If these involve more than 50% of the joint they will need surgical intervention.

Lateral radial or ulnar forces may rupture collatearl volar ligaments resulting in ulnar or radial deviated dislocation.

If rotational longtidunal force can distrupt both colateral and volar plate making very difficult to reduce.

Splint in 20-30 degrees of flexion or with an extension block splint

Question 18

Discuss metacarpophalangeal joint injury

Answer 18

Collateral and volar ligaments stablize the joint deep and superficial transverse ligaments also aid to stability. The joint is more stable in a flexed position where the collateral ligaments are stretched.

Caused by hyperextenion. simple dislocation are often subluxed with the joint resting in 60 degrees of hyperextenion with tender ecchymotic swelling.

Complex discloation are complete disarticulation and are unstbale. They may appear less hyperextended howevere you are able to feel a palpable displaced metacarpal head which will dimple the palm.

Hyperextension and lontidunal traction should be avoided as can lead to entrapment of the volar plate in the joint space. Simple subluxed MCPJ should be reduced with the wrist in flexion and with direct dorsal pressureon the proximal phalanx. Complex dislocation need hand service as both dorsal and volar dislocation are unstable.

Question 19

Discuss carpometacarpal joint injury

Answer 19

CMC joint is composed of the 8 carpal bones their ligamentous communciations and the metacaprals forming the hand’s transverse metacarpal arch.

CMC injury is rare and easily missed seen in high impact injury such as closed fist injuries. The fifth digital dorsal CMC joint is the most common to be dislocated. Often will need hand service

Question 20

Discuss ulnar collateral ligament injuries (game keepers and stenar lesions)

Answer 20

The thumb ulnar collatyeral ligament injury (gamekeepers thumb). Seen with repeated forced abduction of the MCP resulting in ligamentous injury at the insertion of the proximal phalanx.

May be associated with an avulsion fracutre and result in a complete or incomplete ligament tear. Inadequate management or repeat injury can lead to chronic disability.

A stenar lesion occurs when the superficial portion of the ligament is drain proximally. Ulnar deviation of the MCP joint allows the adductor pollic tender to interpose between the superifical and deep portion of the ligament leading to inproper healing in 2/3 of cases.

Managed with a thumb spiker splint and outpatient hand service refferal. Surgery within 3 weeks leads to good clinical outcome/

Question 21

Discuss zone 1 injuries to the extensor tendons

Answer 21

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.

Question 22

Discuss zone 2 injuries of the extensor region

Answer 22

The extensor tenden central and lateral bands pass through this region over the middle phalanx. The central band attaches to the middle phalanx and the lateral bands extend to the base of the distal phalanx.

Treatment options are the same for zone 1 injuries

Question 23

Discuss zone 3 injuries of the extensor region

Answer 23

Second most comon sports related tendon injury involves the central tendon as it passes dorsally over the PIP. Causes of closed injury include forced flexion and extension and rush to the dorsum of the PIP. At this level laceration may involve both the tendon and the joint.

A boutonneires deformity may result from damage and displacement of the extensor hood as well as the attachements of the central tendons lateral bands resulting in flexion at the PIP and hyperextension at the DIP.

Closed zone 3 injuries should be splinted with hand surgeon referral. Open should recieve prophylactic antibiotics and immediate review

Question 24

Discuss zone 4 injuries of the extensor compartment

Answer 24

Partial and complete tendon injuries over the proximal phalanx do not retract appreciably and can be repaired using 5.0 nonabsorbable sutures. followed by immobilization int he funcitonal position

Question 25

Discuss zone 5 injuries extensor compratment

Answer 25

Invovled the MCPJ. Clenched fist injuries can be closed or open. The inability to fully extend the MCPJ with localised swelling suggests tendon injury. Unless proven otherwise all open injuries of the MCPJ should be assumed to be fight bites. Wounds should left opened and patient should be covered for staph, trep, eikenella corrodens and anaerobes. Augementin, bactrim, clindamyucin. The incidence of assocaited joitn, tendon or bony injury injury is as high as 75%. Proper exploration of these wounds is necessary to to reveal extensor tendon injury or violation of the jiont capsule.

Question 26

Discuss zone 6 extensor injuries

Answer 26

Tendons over the metacparl bones are superifical. Stength should be tested in isolation and compared to other digits of the same hand and the opposite hand. INjuries in the region should be splinted with the wrist and MCP in the funcitonal position. All of these patient should be referred within 1 - 3 days/

Question 27

Discuss zone 7 and 8 injuries

Answer 27

These invovle tendon inuries to the wrist and forearm and should be referred to hand service consultation for definitive mangement.

Question 28

Discuss volar injuries of the hand

Answer 28

More difficult ot treat than extensor tendor injuries and should all be referred to hand specifialist The intricacy of the hands volar anatomy has given it the nickname of "no man's zone"

Question 29

Discus clinical features of flexor injuries in the hand

Answer 29

up to 90% of the palmaris apnoeurosis injuries are associated with neurovascular or tendinous injury. Passive resting flexion should result in increasingly greater degrees of flexion from the index finger through the little finger. Complete dirsuption of the FDP results in in an extended resting postiion of the DIP joint. Wounds involving the MCPJ are more likley to affect the FDS as they bifuricate in this region. Paradoxically teh FDP becomes the superifical tendon at the level of the pip joint crease. Therefore wounds involving the PIP and DIP are more likley to invovle the FDP FDP function is tested by fixing the PIP and asking the patient to flex the DIP. FDS function is tested by asking the patient to flex the correspnding PIP while the adjacent fingers are held in extension. Becuase the FDP have a common msucle belly in the forearm holding adjacent fingers in extension will inhibit the function of the FDP in the tested finger allowing FDS to be tested in isolation.

Question 30

Discuss vascular injury in the hand

Answer 30

The hand and its digit possess an excellent collateral supply and isloated injuries seldom result in ischaemia. Injuries involving the palmar arches may be difficult to visualise and may require theatre to achieve haemostasis. Arterial repair is not mandatory in isolated arterial injury with preserved distal circulation.

Question 31

Discuss nerve injury to the hand

Answer 31

Three classicfication help define neural injuries. 1. neurapraxia is characterized by complete or partial dyfucntion commonly caused by compression or crush injury. The nerves axon, sheath and endoneurium remain intact and full recovery is expected within days to weeks, 2. Axonotmesis results from disruption of the axon and myelin sheath resulting in distal axonal degenration. The endoneruial tube remains intact allowing the proximal axonal stump to regenerate at a rate of 1-2mm/day. recovery is variable 3. neurotmesis caused commonly by penetrating wounds is characterised by seperation of all nerve elements. Recovery is not expected without reapporixmation

Question 32

Discuss amputation care of stump and wound

Answer 32

Care of the amputated part - irrigate in normal saline do not debrine - pack loosley with sterile saline soaked gauze and place in a plastic bag and store in an ice water slurry- ensure ice dose not directly contact the amputated part Care of the stump -irrigate the stump with saline and control bleeding with direct pressure GIVE analgesia, antibiotics adt

Question 33

Discuss finger tip amputations

Answer 33

fingertip amputation are divided into three zones 1. zone 1 preserve the bone and the proximal 2/3rds of the nail bed 2. zone 2 two thirds of the nail bed has been lost with some exposure to bone 3. zone 3 all nail bed is absent with signifiant bone on view Preervation of length espescially of the thumb and pulp to pulp pinch on the index finger are the main goals. Wounds less than 1cm wihtou bone exposure may be managed through secondary intention healing every thign esle goes to the hand guys, Nail deformity due to matrix loss is common even with repair. neurovasuclar compromise may lead to hyper or hypoaethesia with temperature intolerance.

Question 34

Discuss high pressure injection injuries

Answer 34

Industrial equipment such as water, grease pain and sand injectors with compressive forces of 2000-12000 PSI are sufficient to penetrate skin even from a distance. Initial presentaiton may appear benign but due to the rate of deep tissue infection amputation rates are as high as 48% wihtout intervention. Pain and solvents produce large early inflammatory responses compared to other viscous compounds and results in greater rate of amputation. Velocity and site determine dispersion risk. Distal injury carry greater risk of amputation compared to proximal

Question 35

Discuss paronychia

Answer 35

Infection involving the lateral nail fold commonly caused by local trauma. Can evlove into local cellultiits and abcess with lymphangitic extension. S.aureaus most common bacteria followed by strep, pseudomonas, gram -ve and anaerobic flora. Patient with cellultiis wihtout abcess should be given oral antibiotics and advised to soak the finger multiple times a day, and keep it elevated. Those with local fluctaunce should be drained by lifting the cuticle off the nail to release and drain the pus. Complication include osteomyelitis, chornic indolent process

Question 36

Discuss felon

Answer 36

In an infection resulting from penetrating trauma involving the digital fat paid (the pulp) containing septation that extend vertically from the dsital phalanx to the volar skin, creating a series of individual compartmetns. Infection may continue to be present despite surfical decompression if all compartemtns are not adressed. After a digital block, a felon can be drained by an incision parallel to the length of the phalanx from the base of the fat pad to the free edge of the nail. To avoid pincher surfaces the incision should be made dorsal to the neruovascualr bundle along the radial aspect of the thumb and fifth digit and the ulnar aspect of the 2-4 digits. Pack the wound and soak in warm water dailey. Removed packing in 48-72hours. Treat with oral abs Untreated felons can lead to skin necrosis sinus tract formation and chronic drainage.

Question 37

Discuss herpatic whitlow

Answer 37

Self limiting manifestation of human herpes eimplex type 1 or 2. usually a single digit is involved with local erythema swlling and painful pruritis, Systemic symptoms are absent, . Clear vesciular lesions evolve over the area over a 2 week period. Do not D&C as may lead to dissementation of the virus. Topical antivirals have not been shown to have benefit either therapeutically or prophylacticallty Symptoms self resolve over 3-4 weeks but will recur in 20% of cases Can consider oral antivirals in the immumocompromised.

Question 38

Discuss tenosynovitis

Answer 38

Synovial space infection involves the felxor tendon sheaths and assoicated bursae.The thumb and fifth digit sheaths are continuous with the radial and ulnar plmar bursae. These bursae communicate wiht each other in 80% of patients. The sheaths and associated bursae of the 2-4th digits do not communicate wiht each other. Clinical features include 1. palpable tenderness along the tendon sheat 2. pain on passive extension 3. symmetic digitial swelling 4. digit fixed in a semiflexed position Patient with tenosynovitis require hospital admissio, iv anitbiotics, immobilization, elevation of the affected extremity and hand service.

Question 39

Discuss deep space infection

Answer 39

There are superficial and depp facial compartment in the hand that are potential spaces for the origin and spread of infection. Three superficial spaces include the dorsal subcutaneous space, sub aponeurotic space and interdigital web space. Three anterior plamr spaces include the thenar, hyperthenar and midplamar spaces. Concurrent subcutaneous involvement is the rule not the excpetion. Symptoms including pain out of proportion to the clinical finding and deep space tenderness with digital motion should raise concer.

Question 40

Discuss indication and contraindication for re-implantment

Answer 40

INDICATIONS * Primary * thumb at any level * multiple digits * through the palm * wrist level or proximal to the wirst * almost all part in children * Relative * individual digits distal to the insertion of the FDS (Zone 1) * ring alvulsion * through or above elbow CONTRAINDIACTIONS * Primary * severe vascular disorder * mangled limb or crush injury * segmental amputation * prolonged ischamiea time with large muscle contact * Relative * Medically unstable * disabling psych illness * tissue contamination * prolonged ischaemia

Question 41

Discuss ischaemic time for re-implantation

Answer 41

Time to repplantaiton * Proximal to the carpus * warm time \<6 hours * cold time \<12 hours * Distal to carpus * Warm time \<12 houts * Cold time \<24 horus