Finger tip injuries are extremely common injuries. They commonly occur as a result of workplace related injury, domestic or sports injuries and rarely from frostbite and vascular injuries. Nail bed injuries are important and thus its recognition, accurate evaluation and correct management is of paramount importance. Thus readers are encouraged to make themselves familiar with the detailed anatomy, classification of injuries and emergent and definitive treatment. More complex and serious injuries also need referral to specialised hand or plastic surgical units are appropriate. Correct management of these conditions also aborts the much feared Reflex Sympathetic Dystrophy or the Complex Regional Pain Syndromes which are not an uncommon occurrence with these injuries.

Traditionally the nailbed is described as being part of what is known anatomically as the “The Nail Unit”

  • The nail unit or the 'perionychium' consists of the hyponychium, nail matrix, nail fold and the nail
  • The nail matrix consists of the germinal matrix (proximally) and the sterile matrix (distally) and
  • The lunula (which is a white arc on the nail distal to the eponychium) is the visible part of the germinal matrix and the nail bed distal to it is the sterile matrix

The nail bed gets its vascular supply by the palmar digital artery. This rich capillary network of the nail bed has been shown to be made up of capillary loops that vary in size, length and number in various areas

Mechanisms and Classification of Nail Bed Injury

  • Crush injuries are by far the most common cause
  • Car or house door injuries (particularly common in children)
  • Crushing between moving parts in machinery
  • Iatrogenic injuries (after improper or traumatic nail removal and glomus tumour removal)

Classification of Nail Bed injuries:
It is important to classify nail bed injuries so as to determine the best way of treatment for speedy return to normal anatomy and to regain full movement, sensation and thus function. Various classifications are in vogue but the most popular ones are as follows:

Rosenthal classification

  • Zone I: Distal to bony phalanx
  • Zone II: Distal to lunula
  • Zone III: Proximal to distal end of lunula

Van Beek classification
A) Sterile matrix injury

  • S I: Small nail haematomas (25%)
  • S II: Sterile matrix laceration with large subungual haematoma (50%)
  • S III: Sterile matrix laceration with fracture
  • S IV: Sterile matrix fragmentation
  • S V: Sterile matrix avulsion

B) Germinal matrix injury

  • G I: Small subungual haematoma, proximal nail (25%)
  • G II: Germinal matrix laceration, large subungual haematoma (50%)
  • G III: Germinal matrix laceration and fracture
  • G IV: Germinal matrix fragmentation
  • G V: Germinal matrix avulsion

Evaluation of Nail Bed Injuries:
It is useful to document these injuries using standard “hand charts” found in many hand surgery or reconstructive units across the world. This documentation should include

  • A detailed description of the mechanism of injury
  • Identify hand dominance and patient occupation
  • Radiographs of the injured finger/digit with its findings. This should include documentation of fractures, foreign body or air in soft tissues indicating open injury at the outset
  • Always examine patients in the operating theatre, preferably under anaesthetic and only ONCE with the prospective surgeon with responsibility for immediate management to avoid unnecessary re-dressings which accentuate soft tissue injuries further and may compromise tissues with precarious viability
  • Use operating loupes when repairing the nail bed

Management of Fingertip Injuries:

  • The first attempt at repair is the best attempt for achieving superior results. Make sure you are conversant with these injuries and their management. If not get senior and more experienced help.
  • Always paint and prepare the extremity to the proximal forearm and any potential graft donor sites
  • Undertake meticulous wound toilet, surgical washout and appropriate yet minimal debridement. Use a syringe with a wide bore needle for lavage. Small calibre needles cause excess injection pressures and tissue undermining and thus best avoided in these sensitive and delicate areas.
  • Ensure accurate apposition and repair of the lacerated nail bed
  • Replace like with like tissue if considering a graft
  • Preserve skin folds surrounding nail margins
  • Prevent adhesions within nail folds (especially between the eponychial fold and underlying nail bed)
  • Fractures should be accurately reduced
  • Ensure a flat surface that is long enough for nail growth
  • Restore fingertip skin and pulp if feasible
  • Excise all remnants of the germinal matrix if terminalisation is considered

Acute Paronychial Injuries:
These are injuries to the skin folds to the side of the nail and commonly associated with nailbed injury. Some simple principles to be followed in the acute setting are:

  • Simple lacerations should be repaired prior to any associated nail bed injury
  • Avulsion or amputation of a portion of the paronychium requires more intensive management in the form of local or regional flaps
  • The commonly used flaps for such injuries are the volar and lateral V-Y advancement flaps, cross finger flap and thenar flap. V-Y advancement flap is limited in that it cannot be advanced more than 5mm-10mm
  • Small defects may be covered with full thickness skin grafts

Proximal Nail Fold Injuries:
The proximal nail fold contains the dorsal roof of the nail bed; therefore injuries to this area have a direct impact on nail formation.

  • Simple lacerations can be managed by accurate appositions of the skin margins and repairing with 6/0 Vicryl-rapide (irradiated polyglactin 910)
  • Loss of tissue should be replaced with like tissue if possible

Subungual Haematomas:

  • Haematomas of any size should be evacuated if causing severe pain
  • Radiological evaluation is mandatory to rule out an underlying phalangeal fractures or foreignbody presence
  • Haematomas involving up to 25% of the visible nail bed area should be trephined for pain relief
  • A red hot paper clip or ophthalmic cautery or sharp objects like a needle or fine tip scalpel may be used heated on an ordinary lighter flame until red hot. These treatments are surprisingly painless
  • Haematomas involving 25-50 % of the visible nail bed area has two options of treatment

– If the nail plate is still partially adherent and not displaced from the nail fold, it may be left in place and the haematoma managed by trephining or observation
– If in doubt, the nail bed should be exposed and explored

  • Haematoma larger than 50% of the visible nail bed area should be managed by removing the nail plate and repairing the underlying injured nail bed
  • If there is any underlying fracture of the terminal phalanx, then it should be treated like any open fracture with copious lavage, debridement, bone fixation and nail bed repair

Simple and Stellate Lacerations:

  • This needs complete removal of the nail and exploration of the nail bed
  • The nail should be removed carefully using an artery clip or a periosteal elevator
  • The laceration should be accurately repaired using 6/0 Vicryl-rapide (irradiated polyglactin 910)
  • If the nail plate is available and clean, it should be replaced. The nail allows accurate moulding of the nail bed as well acts as an external splint in case of concomitant distal phalanx fracture
  • The nail may be fixed with Histocryl(tissue glue), using five drops applied to the sterile matrix using a blue hypodermic needle as an applicator

Recent studies have indicated two methods to repair the nail
a) modified tension band sutures
b) transverse figure-of-eight suture

  • The finger should be dressed with non adherent dressing and examined in five to seven days
  • A Zimmer aluminium splint may be used after surgery to protect the tip. This can be replaced by a thermoplastic cap splint at the first dressing change
  • Tapping exercises, essential to desensitise the fingertip should be started once the initial post-operative pain has settled

Crush Injuries:

  • Crush injuries/burst lacerations are more serious injuries and have a poor prognosis
  • Debridement should be kept to a minimum. Any fragments of the nail bed attached to the nail plate should be replaced accurately
  • A split nail graft can be harvested from the great toe
  • Antibiotic cover is essential

Avulsion Injuries:
Sterile matrix avulsion

  • If there is loss of the sterile matrix then this should be replaced with similar tissue
  • Split thickness sterile matrix grafts from the adjacent matrix can be used to cover small defects
  • For losses more than 50% grafts should be harvested from the great toe

Germinal matrix avulsion

  • Germinal matrix avulsion is a difficult issue to resolve
  • The types of grafts used are free graft, acute toe to finger composite graft transfer, split thickness grafts, reverse dermal grafts, full thickness nail bed grafts

Fractures With Lacerations:

  • Approximately 50% of nail bed injuries are associated with distal phalangeal tuft fractures
  • It is vital to reduce the fracture as the support of the bone is essential for normal nail growth. The nail itself acts as an external splint and may be all that is needed to maintain the reduction
  • All displaced fractures should be reduced and may be fixed by pinning the fracture

Amputations:
Amputations are combined nail bed and fingertip injuries. They are classified by various systems, the commonly used ones being:

Rosenthal classification

  • Zone I: Distal to the bony phalanx . Nonoperative treatment is usually required and advised.
  • Zone II: Distal to the lunula. Local or distal pedicle flap reconstruction is the treatment option available.
  • Zone III: Proximal to the distal end of the lunula

Amputation may be the only option if the nail bed and the pulp are badly damaged where the level is determined by the viability of the proposed flaps.

The indicator planes as described by Klienert must be taken into consideration when pedicle reconstruction is planned.

  • Dorsal
  • Volar
  • Transverse
  • Central
  • Axial

Reconstructive Flaps:

  • The flaps could be local (adjacent tissue) or distal (remote) based pedicle flaps
  • The aim is to provide a sensate non-tender tip with stable soft tissue cover and local flaps maintain the sensibility of the fingertip

Local flaps:

  • Local flaps are used most frequently in Zone II injuries
  • Volar V-Y flaps and bi-axial V-Y flaps (Kutler flap) may be used
  • Local flaps are limited by the length by which they be transferred
  • Free neurovascular pedicle grafts circumvent such problems. Examples include axial V-Y neurovascular flap (Atasoy flap), dorso-lateral and volar advancement flaps
  • These flaps are required in areas with more extensive tissue loss and the thumb

Distal flaps:

  • Distal flaps are used for most Zone III and volar oblique Zone II injuries
  • Thenar and cross finger flaps are examples of such flaps
  • Thenar flaps provide a better cosmetic result and better sensibility
  • These flaps could be based either distally or proximally however the cross finger flap can be used axially as well
  • The donor site usually requires a full thickness skin graft except in children and adolescents in whom the skin is more pliable

Summary

  • The ultimate goal of treatment of an injury to the fingertip is a painless fingertip with durable and sensate skin
  • Knowledge of fingertip anatomy and the available techniques of treatment is essential
  • Early recognition and management of these injuries can prevent distressing and cosmetically unacceptable nail and fingertip deformities
  • The outcome of nail-bed injuries is most dependent on the severity of injury to the germinal matrix

Vascular Injuries to the Hand:

  • The hand is supplied by the branches of the ulnar and radial arteries

Ulnar artery

  • The ulnar artery at the level of wrist divides into two branches, which enter into the formation of the superficial and deep volar arches
  • The deep volar branch anastomoses with the radial artery and completes the deep volar arch
  • The superficial volar arch formed by the ulnar artery and the arch passes across the palm, describing a curve with its convexity downward
  • Three palmar digital arteries arise from the convexity of the arch and divides into a pair of collateral digital arteries

Radial artery

  • The radial artery in the hand unites with the deep volar branch of the ulnar artery to form the deep volar arch
  • The volar metacarpal branches in the hand are from the radial artery

Causes of Vascular Injuries:
The most common causes of hand vascular injuries are

a) Trauma

  • Lacerations from broken glass
  • Penetrating trauma
  • Stab wounds
  • Blunt vascular trauma after automobile accidents and athletic injuries result in intimal tears and subsequent thrombosis
  • Iatrogenic trauma secondary to the widespread use of diagnostic and therapeutic intravascular techniques has also contributed to the increase in incidence

b) Compression
c) Occlusion
d) Tumours / malformations
e) Vasospasm

Clinical Examination

  • A thorough history and careful physical examination
  • Fractures and dislocations should be reduced before examination

Hard signs

  • Pulsatile bleeding
  • Expanding haematoma
  • Thrill or bruit
  • Evidence of ischemia (pallor, paresthesia, paralysis, pain, pulselessness, and poikilothermia)

These obvious signs almost always indicate an underlying arterial injury and are indications for immediate surgical intervention.

Soft signs

  • Stable haematoma
  • Proximity to a penetrating wound
  • Peripheral nerve deficit
  • Associated fracture or dislocation

These equivocal signs may indicate the need for further evaluation with Doppler studies, arteriography, or surgical exploration to confirm or exclude vascular injury.

  • A palpable radial pulse does not exclude a proximal vascular injury
  • The collateral circulation in the hand can be objectively assessed by performing the Allen test

Investigations:

  • The arterial pressure index (API) measured with a hand-held Doppler unit is a useful adjunct to the physical examination. Results from studies have indicated that an API of < 0.90 had 95% sensitivity and 97% specificity for occult arterial injury. An API of > 0.90 had a negative predictive value of 99%.6
  • Doppler or ultrasound examination of the blood flow in the arteries and veins.
  • Segmental arterial pressure and pulse volume recordings, which assess the quality of blood flow in the vessels using small blood pressure cuffs and ultrasound transducers placed on the fingers and arm.
  • Magnetic resonance angiography. A MRI of the affected area is per formed with special attention dedicated to the vessels (MRI/MRA)
  • Arteriography. Contrast is injected into the vessel and X-rays taken of the hand and arm. This is an invasive test and depicts the details of the vessels.

Surgical Management:

Initial evaluation and management

  • Advanced Trauma Life Support (ATLS) guidelines established by the American College of Surgeons

Repair of peripheral vascular injuries

  • The operative sequence consists of access, exposure, control, and repair
  • Temporary vascular control can usually be accomplished with the application of digital pressure or a blood pressure cuff
  • An attempt to blindly clamp a bleeding vessel is not recommended because of the hazard of injuring a nerve. This should always be undertaken in the operating room with a tourniquet in place to be inflated when required
  • If initial repair of associated nerve and tendon injuries is not feasible, they should be tagged for later repair
  • Gaining access and exposure without iatrogenic injury is a fundamental part of the operation
  • Repair is mandatory if the palmar arch is incomplete or if the ulnar or radial artery was previously interrupted
  • When both are injured, the ulnar artery takes preference because of its dominant supply
  • Topical lidocaine or papaverine is useful to paint affected vessels to relieve spasm and re-establish blood flow

Vascular Repair:

  • The type of vascular repair depends on the extent of arterial damage
  • Primary repair with an end-to-end or end -to- side anastomosis is performed with a running or interrupted nonabsorbable monofilament suture, depending on the size of the vessel
  • Nylon suture material of sizes 9-0,10-0,11-0 and 12-0 may be used
  • A meticulous surgical technique must be used to avoid a purse-string effect
  • If a large gap prevents tension-free repair, reversed saphenous or cephalic-vein autogenous interposition grafts must be used for reconstruction
  • Polytetrafluoroethylene (PTFE) grafts should be avoided as possible because they increase the risk for infection and an inferior patency rate, especially in small vessels

Post-Operative Management:

  • All repairs must be covered with viable soft tissue, and external compression must be avoided
  • Intraoperative completion arteriography must be performed, and palpable distal pulses should be documented after repair
  • Venous injury to the upper extremity rarely requires repair because the collateral network is extensive
  • Endovascular Treatment: Endoluminal repair of false aneurysms, large arteriovenous fistulas, intimal flaps, and focal lacerations, is performed by using stent-graft technology.

Early complications following vascular Injuries

a) Compartment syndrome

  • Due to reperfusion injury
  • The 4 compartments in the hand are the central, thenar, hypothenar and interossei compartments
  • Five incisions are used to decompress the hand: 2 placed on the dorsum, 1 over the carpal tunnel, and 2 on the thenar and hypothenar eminence

b) Infections

  • Requires immediate debridement and antibiotic treatment

Late complications
a) Arteriovenous fistula
b) False aneurysms

  • These complications are usually managed with operative repair

Summary

  • Vascular trauma of the hand is increasingly common. It causes a high degree of morbidity with severe consequences on function
  • The surgeon must have knowledge of the vascular anatomy and of the surgical techniques available, and must be able to intervene in a systematic approach with a high index of suspicion
  • Successful management with good outcomes depends on early diagnosis and prompt intervention

Recommended Reading:

  1. Hasegawa K, Pereira B P, Pho R W H .The microvasculature of the nail bed, nail matrix, and nail fold of a normal human fingertip. Journal of Hand Surgery. March 2001 Vol. 26, Issue 2, Pages 283- 290.
  2. Chakravarthy J, Qureshi A, Waldram MA .et.al. Acute fingertip Injuries.Trauma.2006; 8: 179-188
  3. Klienert HE, Putcha SM, Ashbell TS. et. al .The deformed finger nail. A frequent result of failure to repair nail bed injuries. J Trauma 1967. 7(2): 177-90.
  4. Patankar H S.Use of modified tension band sutures for fingernail disruptions. Journal of Hand Surgery (European Volume, 2007) 32E: 6: 668-674.
  5. Bristol S G, Verchere C G .The Transverse Figure-of-Eight Suture for Securing the Nail .Journal of Hand Surgery .January 2007 .Vol. 32, Issue 1, Pages 124-125.
  6. Johansen K, Lynch K, Paun M .et.al.