Sections

Technique

Approach Considerations

With most fingertip injuries, the choice of technique depends on the geometry of the fingertip injury (see the image below) and, to a certain extent, the expertise of the surgeon. The loss of tissue at the fingertip may be transverse or oblique, with more tissue loss on the volar side or on the dorsal side. Some amputations may take more tissue from one side or the other (ie, the radial or the ulnar side).

Geometry of fingertip amputations.

View Media Gallery

The main techniques currently available for repairing fingertip amputations are as follows:

Open technique (nonoperative; healing by secondary intention)
Skin graft
Reamputation
V-Y flap (Kutler or Atasoy)
Volar flap advancement (Moberg) ^[3]
Bipedicle dorsal flap
Crossfinger flap
Thenar flap

Each of these techniques is discussed separately below. Surgical preferences vary substantially.^{[8, 9]}

Additional techniques have been described, including the palmar pivot flap for lateral defects in the fingertip injuries,^[10]the reverse midpalmar island flap for complex reconstruction of fingertip amputations,^[11] and the fenestrated adipofascial reverse (FAR) flap.^[12]However, these techniques are not yet as commonly used as those listed above.

Fingertip replantation has become an established technique with the potential to yield excellent outcomes, but it remains technically challenging.^[4] and has not been as commonly performed in the United States as it has elsewhere in the world.^[1]

Open technique

This is nonoperative management of fingertip amputation in which the loss of skin or pulp is less than 1 cm², which can heal by secondary intention.

The wound requires cleaning and dressing at regular intervals. Advise the patient to begin 1 week after the procedure to soak the finger in a warm water-peroxide solution daily and then apply the dressings with a fingertip protector.

In selected cases, where the tip of the bone is exposed, it can be trimmed with bone cutters to the level of the soft tissues and then allowed to heal by secondary intention. However, better results are usually achieved in such cases if an additional procedure is performed.

Complete healing takes place in 3-6 weeks.

Skin graft

Larger wounds allowed to heal by secondary intention may result in a thin, nondurable layer of epithelium. In such cases, skin grafting from the palmar surface is preferred, and these are generally taken as full-thickness skin grafts.

The preferred donor site is the hypothenar area of the palm. The full-thickness skin graft taken from this site is durable and is an excellent cosmetic match to the pulp of the finger. Also, this donor site is convenient from the surgeon's perspective.

When the full-thickness graft is taken, the underlying fat should be completely removed before application.

The other areas from which a full-thickness graft can be procured are the medial aspect of the arm distal to the axilla, the volar side of the forearm and wrist, and the amputated part of the fingertip, if it is available. The latter can be performed more successfully in children than in adults.

Split-thickness grafts can also be performed; however, full-thickness grafts are preferable for their durability. Also, split-thickness grafts contract with time while healing.

Reamputation

Shortening and primary suturing can be done in certain cases.

When shortening is contemplated for fingertip injuries, remove the remaining germinal matrix of the nail to prevent future problems from the nail remnant. To do this, make incisions on either side of the nail wall and reflect the nail wall proximally, extending from the eponychium. If shortening leaves the patient with a stump of distal phalanx, carry out disarticulation at the level of the distal interphalangeal (DIP) joint.

Remove the prominent volar condyles of the middle phalanx with a bone cutter or a rongeur. Pull the flexor and extensor tendons distally and transect them, then allow them to retract. Excise the palmar plate and the collateral ligaments to avoid bulking of the tip and give a better contour to the tip. To avoid painful neuromas, identify the digital nerves and dissect them proximally, then pull and transect them 1 cm proximally from the skin edge (tip).

If the plane of the amputation is transverse, bring the palmar skin forward to suture with the dorsal skin. If a long flap of skin is available, as in cases where the plane of the injury is oblique, use the excess skin to cover the tip as a flap. Suture the skin without any dog ears.

V-Y flap

After trimming the bone ends, in cases of distal transverse fingertip amputations, create a V-Y flap with a triangular flap that has the wound edge as its base. The apex should be the midpoint of the DIP joint. Only the full thickness of the skin is cut. (See the image below.)

V-Y flap.

View Media Gallery

Adequately mobilize this flap by passing a No. 15 blade tangentially on the volar aspect of the bone from the distal edge of the wound. Use the knife blade to divide all the fibrous septa anchoring the pulp to the underlying bone. Once the flap is completely mobilized, pull it over the fingertip and suture it to the nail bed dorsally.

At this juncture, release the tourniquet to assess the capillary refilling of the flap. A pale flap indicates that the flap is not adequately mobilized and that the vessels are stretched. In this case, remobilize the flap, taking care to divide all the fibrous septa anchoring the pulp to the underlying distal phalanx.

Once satisfactory capillary refilling is present in the mobilized flap, close the rest of the wound with V-Y plasty without any tension.

A dorsal V-Y flap is described in the literature, used for volar oblique fingertip amputations with more volar soft-tissue loss.^[13] A double V-Y flap technique has been described for cases where a simple V-Y flap does not provide sufficient coverage.^[14]

Volar flap advancement

A volar flap is normally used for injuries to the tip of the thumb. (See the image below.)

Moberg flap.

View Media Gallery

After the debridement of the fingertip, make midlateral incisions dorsal to the neurovascular bundles, and dissect the flap from the flexor tendon sheath. Mobilize the flap and advance it along with the neurovascular bundles. The advancement is helped by flexion of the interphalangeal (IP) joint of the thumb. If the flap is under tension, perform a transverse incision on the skin at the base of the flap. This results in a rectangular defect that needs a full-thickness skin graft.

In the other fingers, the prospect of flap survival is increased by limiting the volar flap incisions distal to the proximal interphalangeal (PIP) joint.

Bipedicle dorsal flap

Start the incision at the proximal margin of the fingertip defect, and proceed proximally on the dorsum of the finger to elevate skin and subcutaneous tissue. At a more proximal level, make a transverse dorsal incision to create a bipedicle graft to cover the defect at the fingertip.

The flap can be made more mobile by dividing one of the pedicles; however, this comes with the price of increased chance of necrosis of the flap. Use a full-thickness skin graft from the volar aspect of the distal forearm to cover the defect created by taking the flap.

Crossfinger pedicle flap

The crossfinger pedicle flap technique calls for proper planning, templating, and forming of a pattern before the flap is actually created. The technique also depends on the size and location of the defect and the other finger injuries.

The flap can be based either proximally or distally. More commonly, the flap is taken from the neighboring ulnar finger with the base laterally. The flap is taken from the dorsal aspect. Keep the template 2 mm larger than the required size so that the final suturing can be done without tension.

Dissect the flap down to the plane between the subcutaneous fat and the paratenon of the extensor tendon. Check the vascularity of the flap, and then apply it over the defect in the adjacent fingertip. Fill the defect in the donor area with a full-thickness skin graft taken from the groin.

To minimize the chance of crossfinger pedicle flap failure, transfix the middle phalanges of the two fingers with K-wires. This prevents excessive tension and torsion of the flap.

When the procedure is complete, apply a large bulky dressing. Detach the pedicle 2 weeks after the initial procedure. Gradually attempt mobilization for the fingers to avoid finger stiffness.

Thenar flap

With the thumb in abduction, flex the injured finger so that the tip touches the thenar eminence.^[15](See the image below.)

Thenar flap.

View Media Gallery

Mark the margins of the flap so that enough tissue is available to suture without tension. Design the flap with the base proximally. The length of the flap should not be more than twice the width of the flap.

Raise the flap with as much of the underlying subcutaneous fat and suture it to the fingertip without tension. Close the defect in the donor area primarily; a graft is not needed. The flap should not have any buckling or kinking that may interfere with the vascularity.

Apply a large bulky dressing. After 48 hours, change to light dressing with the flap partially exposed. After 2 weeks, detach the pedicle.

Considerations in pediatric patients

Amputations through the eponychium may be replanted with variable success. Revision amputation is usually performed at the level of the eponychium. If at least 25% of the nail bed is present, the patient benefits from maintaining that nail. However, resection is recommended if less than 25% of the nail bed is present.

In children, the tip of the finger is often avulsed with the nail bed. In such cases, approximations are made of the edge of the nail bed and skin tip as a composite graft. To hold the bone in place, longitudinal or crossed pins are used. The younger the child, the better adherence of composite graft of skin and nail bed are seen. The greatest success rates are seen in children aged 3 years or younger. However, in an older child, a cap graft is likely to hold greater success.

Complications

Postoperative complications can be broadly divided into problems at the site of nail growth (sterile matrix) and problems at the site of nail support (distal phalanx), as follows.

Sterile matrix problems - A scar within the sterile matrix can result in various deformities, such as notching, nonadherence, splitting, and elevation of the nail; such problems prevent growth or adherence to the nail bed scar
Distal phalanx problems - Excessive debridement can lead to an uneven dorsal cortex and loss of bony support, resulting in nonunion of the distal phalanx or osteomyelitis

Early postoperative complications of an amputated stump include wound hematoma, infection, and necrosis. To minimize the risk of infection, irrigation and debridement of the amputation wounds are required. Antibiotic prophylaxis does not appear to decrease the incidence of infection.^[16] Hemostatic control of the amputation stump can be achieved initially with a tourniquet.

If subungual hematoma or seroma is present 5-7 days after surgery, reopen the nail trephination hole or gently raise the nail at the paronychia to permit drainage. The suture used to hold the nail in place should be removed 5-7 days after the injury to prevent a sinus tract formation through the nail fold. In simple subungual hematoma, regardless of size, nail removal with suture repair of the nail bed is unnecessary. For more information, see Hand, Subungual Hematoma Drainage.

Particular techniques are predisposed to particular complications, as described below.