Fingertip Amputation

Fingertip injuries are among the most common injuries of the hand, and appropriate treatment depends on the type of injury and the involvement of other digits.

Fingertip amputation occurs distal to the insertion of flexor or extensor tendons into the distal phalanx. Numerous techniques are available for the repair of fingertip amputations, with the common goal of reducing pain and preserving sensation at the tip (see Technique). ^{[1, 2]} The appropriate approach depends on the amount of tissue involved, the involvement of bone (distal phalanx), the angles and levels of amputation, and the involvement of other fingers or the rest of the hand.

Techniques discussed in this article 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

Fingertip replantation has become an established technique with the potential to yield excellent outcomes, but it remains technically challenging. ^[4]  

Indications for the various techniques employed in fingertip amputation vary, as follows. (See Technique.)

If the fingertip injury is less than 1 cm² or is in a child with adequate soft-tissue cover over the bone, it can be managed nonoperatively with secondary healing.

Larger fingertip injuries that cannot be managed nonoperatively with healing by secondary intention alone—that is, those with a thin layer of epithelium that is not durable—can be treated with skin grafts taken from the hairless ulnar side of the hand.

With regard to reamputation, if the bone is protruding, the bone can be shortened and primary closure performed, or the wound can be left open for healing by secondary intention with granulation tissue. This approach is appropriate in adults with injuries that have less than 5 mm of sterile nail matrix present. It is also relatively indicated in patients with significant systemic conditions, for whom regional flaps are contraindicated and  techniques such as skin graft or open technique are not possible.

A V-Y flap is indicated if the angle of fingertip amputation is either oblique with more tissue loss dorsally or transverse. It can be performed only if significant palmar tissue is available for dorsal advancement.

Volar flap advancement was previously used for all fingers; currently, it is recommended only for thumb fingertip amputation where less than 1.5 cm of advancement is required for coverage. In other fingers, the venous drainage depends on the volar flap, and this technique thus increases the risk of necrosis of the entire flap.

A bipedicle dorsal flap is indicated only for cases in which the fingertip amputation is proximal to the nail bed and in which preserving all its remaining length is essential but attaching to another finger is not desirable.

A crossfinger flap is indicated when local flaps are not possible and maintaining the remaining length is essential. It is especially useful in multiple-digit injury, where maintenance of length in the remaining injured fingertips is considered essential.

A thenar flap is indicated in any fingertip amputation with exposed bone.

Contraindications for the various techniques employed in fingertip amputation vary, as follows. (See Technique.)

Open technique is contraindicated in any fingertip amputation with exposed bone. It is relatively contraindicated in injuries in adults that include tissue loss of more than 1 cm².

Skin graft alone is insufficient in fingertip amputation with exposed bone.

Reamputation is relatively contraindicated in cases where maintaining remaining length is essential. Otherwise, this procedure can be performed in most cases, though it is not always advantageous, because length is lost.

A V-Y flap is contraindicated when the geometry of the fingertip amputation is oblique with more tissue loss on the volar side. Furthermore, this procedure is not possible with more proximal fingertip amputations.

Volar flap advancement is relatively contraindicated in fingers other than the thumb, in that it may result in necrosis of the whole flap. Also, if the defect is more than 2 cm, this technique should not be used.

A bipedicle dorsal flap is not possible when the fingertip amputation is very distal and in cases where the soft tissue loss is significantly at the sides.

A crossfinger flap is avoided in patients older than 50 years and in hands with arthritis or a tendency toward finger stiffness. It is also avoided if local infection is present.

Any tendency toward finger stiffness is a relative contraindication for a thenar flap.

Anatomy

The basic skeleton of the wrist and hand comprises a total of 27 bones. The hand is innervated by three nerves (median, ulnar, and radial), each of which has sensory and motor components. The muscles of the hand are divided into intrinsic and extrinsic groups.

The hand contains 14 phalanges. Each digit contains three phalanges (proximal, middle, and distal), except for the thumb, which only has two phalanges. To avoid confusion, each digit is referred to by its name (thumb, index, long, ring, and small) rather than by number.

The nails are specialized skin appendages derived from the epidermis. The nail bed has a germinal matrix, sterile matrix, and hyponychium. ABout 90% of the nail plate is produced by the germinal matrix, which approximately corresponds to the lunula (the pale semicircle in the proximal nail bed). This germinal matrix starts proximally at the base of the distal phalanx just distal to the insertion of the extensor tendon.

The entire nail matrix is in intimate contact with the periosteum of the distal phalanx; therefore, it is vulnerable to injury when the latter is fractured.

For more information about the relevant anatomy, see Hand Anatomy.

Arsalan-Werner et al retrospectively analyzed a cohort of 28 patients with traumatic fingertip amputation (29 fingers) of Allen type III/IV injuries who underwent reconstruction with a neurovascular island flap in order to examine the long-term clinical outcome of of this approach. ^[5]  No mandatory splinting was applied postoperatively. Patients were followed for a mean of 8 years after reconstruction.

The study documented no intraoperative complications, and all flaps survived. ^[5] Active motion of the fingers was over 95% of the contralateral side at follow-up. The grip strength of the affected hand and of each of the affected fingers exceeded 70% of the contralateral side. No significant difference was detected between the two sides on the Semmes-Weinstein monofilament test, but two-point discrimination was significantly impaired on the affected side. The Disabilities of the Arm, Shoulder, and Hand (DASH) score was 16.0. All patients returned to their original occupation, and there was a high level of patient satisfaction with the procedure.

In a retrospective study that included 37 patients with Tamai zone 1 fingertip amputation of the index or middle finger, Nakanishi et al compared the clinical results of two surgical procedures for fingertip amputation: reconstruction with a digital artery flap (n = 23) and microsurgical replantation (n = 14). ^[6]  At a mean follow-up of 34 months, there were no significant differences between groups with regard to the primary outcomes (hand dexterity and disability of the upper extremity), but the secondary outcomes (strength, digital sensitivity, and finger mobility) were significantly better in the reconstruction group.

In a study evaluating the long-term (>10 y) outcomes of 34 successful fingertip replantations in 31 patients, Hayashi et al reported the following ^[7] :

• No chronic pain
• No cold intolerance in 32 digits
• Recovery of protective sensation on Semmes-Weinstein monofilament testing in 27 digits
• Excellent or good recovery on the moving two-point discrimination test in 91% of patients
• Satisfactory sensory recovery, regardless of nerve repair or injury type
• Moderate-to-severe nail deformity in six digits
• Replanted fingertip volume 82 ± 17% that of the contralateral normal digit
• Patient satisfaction rate of 97%