Fingertip Injuries of The Hand

Fingertip injuries can be crushing, tearing, or amputating injuries to the tips of fingers and thumbs. Injury can include damage to skin and soft tissue, bone (distal phalanx), or to the nail and nailbed. The tips of longer fingers tend to be injured more .

Classification of Fingertip Injuries of The Hand

Mostly used classification of fingertip injuries is that described by Allen.

This classification divides injuries of the fingertips into four types. The classification is based on level of injury.

Type 1 Injuries

These injuries involve only the pulp

Type 2 Injuries

Type 2 fingertip injuries involve the pulp and nail bed.

Type 3 Injuries

Type 3 injuries of the fingertip include partial loss of the distal phalanx.

Type 4 Injuries

Type 4 injuries are proximal to the lunula.

Type 1 injuries may heal quite well by secondary intention. Type 3 and 4 often require some type of flap coverage.

Treatment of Fingertip Injuries

Fingertip injuries are defined as those injuries occurring distal to the insertion of the flexor and extensor tendons. They are the most common injuries of the hand and can lead to a significant functional and cosmetic deficit if they are not treated appropriately.

After a fingertip injury, restoration of sensibility, stable skin coverage, and adequate padding are the goals of reconstruction.

There are many treatment options, which range from allowing the wound to heal by secondary intention to flap coverage or revision amputation. No single procedure can be recommended, but each case must be individualized depending on the needs of the patient and the type of injury

Age, occupation, avocation, and general health of the patient needs to be considered  for selecting the treatment.

Any associated nail bed injuries, angle of injury, amount of exposed bone, digit injured, and concomitant injuries also should be considered.

Treatment Options

Healing by Secondary Intention

This is the simplest form of treatment. The simplest treatment of fingertip injuries is to allow the wound to heal by secondary intention.  If required, wound can be debrided. Healing is usually completed by 3 to 6 weeks depending on the size of the defect.

Coverage By Soft Tissue

If the distal amputated part is available and is of adequate integrity it might be used for coverage of the wound espcially in the children.

Reimplantation

If the finger is amputated more than 2 mm proximal to the lunula, then replantation can be considered though microvascular anastomosis is difficult at this level. This procedure requires hand specialist.

Revision Amputation

Amputation at a proximal level is indicated in situations in which bone is exposed and the angle of the injury is such that other options are not appropriate.

As for as possible, the length of the phalanx should be preserved, especially in case of thumb.

Skin Grafts

Skin grafts can be used in injuries where there is skin loss but adequate subcutaneous tissue is present with no exposed bone.

Local Flaps

In these procedures, adjacent local skin with its subcutaneous tissue is used to cover the defect. There are two common advancement flaps used for fingertip injuries.

• • V-Y advancement flap

Regional Flaps

Regional flaps are defined as flaps taken from other parts of the hand that do not use tissue adjacent to the defect and are used for the injuries not amenable to local flaps.

Two commonly used are the cross-finger and thenar flap

Distant Flaps

Flaps are defined obtained from areas of the body other than the injured limb are termed distant flaps. These flaps can be developed from the chest, abdomen, groin, or opposite arm.

Thumb Injuries

Injury to thumb needs the special mention because of its importance in prehension or grasp.

Preservation of length of the thumb is more important functionally than in any other digit. Following are the common procedures used for thumb injuries.

• Moberg advancement flap
• Cross-finger flap
• Palmar cross-finger flap
• Neurovascular island flaps.

Flap surgeries for fingertip injuries

V-Y Flaps For Fingertip Injuries

V-Y Advancement flap was was popularized by Atasoy et al. This procedure is used in fingertip injuries with dorsal angulation or for transverse amputations.

A dorsal angulation injury is an injury which leaves more pulp than nail bed.

The procedure is contraindicated in palmarly angulated injuries as the attempt leads to undue tension on the flap and failure is common.

The V-Y plasty technique preserves the normal contours of the dorsal finger, helps pad the fingertip and preserves normal sensation.

The original technique used a double lateral V-Y pedicle advancement but it has been replaced by V-Y plasty technique described below.

Technique

After giving local anesthesia, wound is cleaned and debridement is done.

A V shaped sull skin thickness incision is given with its apex towards interphalangeal joint and base at the cut edge of the skin, as wide as the greatest width of the amputation. Skin incisions are made through the full thickness of the skin.

This creates a triangular flap which is advanced to cover the defected area.

The repair is carried which converts the V shaped incision to Convert the V-shaped defect into a final Y-shaped wound.

Cross Finger Flap For Fingertip Injuries

First described by Gurdin and Pangman in 1950, cross-finger flap is a useful procedure in fingertip injuries when when maintaining digital length is critical.

The basis of the cross-finger flap is that the skin and soft tissue from the adjacent finger are used to cover the bony and soft tissue defect on the injured finger without bone shortening.

The procedure can be done in patients in whom amputation has occurred in palmar oblique fashion.

Techinique

The procedure is performed in operating room under local anesthesia. After preparation and draping, debridement of the injured finger is done.

A full-thickness skin flap is developed off the dorsal aspect of the middle phalanx of the long finger[Middle finger is used as donor finger in cases of index and ring finger] with a base adjacent to the injured digit.

The cross-finger flap is mobilized and sewn into place over the injured amputated digit.

The injured finger is flexed slightly, and the flap is sewn to the fingertip; thus, both fingers are temporarily sewn together.

The bare area over the donor finger is covered by full-thickness skin graft is obtained from the hip and thigh region.

The fingers are splinted and kept in the position for 2-3 weeks. Following that the bridging piece or pedicle is surgically released.

Photo Cerdit :J Am Acad Orthop Surg 1996;4

Thenar Flap For Fingertip Injuries

A thenar flap surgery involves covering of the amputated fingertip by bending it and suturing the wound to a flap in the thenar eminence at the level of base of thumb.

The injured finger is essentially sutured into the palm so that the finger and the skin flap from the thenar eminence grow together. Later, the finger is separated with its newly acquired tissue

A thenar flap is used to cover a fingertip injury when bone is exposed and preservation of finger length is important.

The thenar flap is best used to provide coverage for the index and middle fingers as the ring and little fingers do not reach the thenar area very well. A similar type of flap from hypothenar eminence may work in these digits.

Procedure

The procedure is performed under local anesthesia. After noting where the injured finger would make a contact with thenar eminence, create a rectangular flap which is slightly longer and wider than the defect it intends to cover. The base of the flap would be on the proximal side of the flap with other three sides being raised.

The finger is bent and the flap is loosely sutured to the finger. The bare donor site can be covered with skin graft or allowed to heal itself.

A splint is applied to maintain the finger position.

The flap is divided after 10–14 days.

Thenar flaps should not be done in patients older than 30 years as it may cause significant joint stiffness.

Palmar Cross Finger Flap

A palmar cross-finger flap has been described for injuries of the distal thumb. The surgical technique is similar to the standard cross-finger flap except the palmar skin is elevated for the flap.

When used for the distal thumb, the long finger is often the donor site.
The flap is designed on the palmar surface of the middle phalanx. Its base should lie along the ulnar border in the midaxial line [A midaxial line is the line passing through centers of proximal and distal interphalangeal joint.]

This procedures carry the risk of

• Exposing the tendon flexor sheath
• Stiffness
• Pain at donor site
• Potential for neurovascular injury.

Moberg Advancement Flap

Moberg advancement flap consists of advancing the the volar skin with its subcutaneous tissues and neurovascular bundles distally into a thumb tip defect.

The unique anatomy of the thumb makes this flap more suitable for the thumb than the other digits.

There is a substantial risk of flexion deformity after this surgery and if it occurs in thumb, it causes little functional problem in thumb than if it occurs in others.

Moreover the thumb is less dependent on the volar blood supply than fingers and there is a risk of tip necrosis with this flap in fingers.

The flap is indicated in volar oblique amputation of the thumb.

Procedure

Under local anesthesia, incisions dorsal to the neurovascular bundles are made in ulnar and radial midaxial lines of thumb.

Metacarpophalangeal joint crease is the usual proximal extent of the flap but may be extended to the thenar eminence for larger defects. A transverse incision at the base may help to advance the flap further towards the tip.

The flap is sutured over the defect and the resulting bare donor area is covered with skin graft.

Neurovascular Island Flap For Thumb

Neurovascular island flap transfers the soft tissue of the border of a finger along with its arterial and nerve supply [Neurovascular bundle] to the thumb.

It is also known as Littler flap.

This provides a soft tissue to the thumb which is sensate though it sacrifices sensation in a finger from which it is transferred.

It can be performed as a primary or reconstructive procedure in thumb injuries.

The donor site of the flap is often the ulnar border of the long finger. Ulnar or radial aspect of the ring finger can also be used.

Procedure

It is important to assess the arterial flow of the donor finger and the digit adjacent to the flap because the adjacent vessel is ligated.

The recepient site is prepared.

The donor site flap is prepared by keeping the distal margin 3 to 4 mm proximal to the midline of the nail plate and carrying out dissection so that neurovascular bundle is harvested along.

The flap, along with neurovascular bundle, is passed over to thumb in tunnel created in superficial fascia.

The flap is sutured on to thumb defect and viability is ascertained.

A full-thickness skin graft is used to cover the bare donor area.

Photo Credit: Hand Surgery

First Dorsal Metacarpal Artery Flap

The first metacarpal artery flap restores sensate skin to the volar thumb in a one-stage procedure without the need for microvascular repair.

The first dorsal metacarpal artery is superficial to the dorsal interosseous fascia. Before making the incision, a Doppler scan may be used to identify the first dorsal metacarpal artery.

The flap can be used to cover thumb defects, either palmarly or dorsally, and can reach from the proximal portion of the thumb almost to its tip.

Procedure

The flap is elevated from the dorsal aspect at the base of the index finger [see video].

It can be extended to the PIP joint distally. Expose the first dorsal metacarpal artery distally to proximally and raise the aponeurosis with the perivascular fat as a pedicle . The flap pedicle includes the first dorsal metacarpal artery and its branches, the first dorsal interosseous fascia, subcutaneous tissue and veins, as well as the radial nerve branches and the accompanying artery.
Once the pedicle is raised, it is tunneled subcutaneously to the thumb without kinking.