Practice Essentials
An amputation is the removal of an extremity or appendage from the body. Amputations in the upper extremity can occur as a result of trauma, or they can be performed in the treatment of congenital or acquired conditions. Although successful replantation represents a technical triumph to the surgeon, the patient's best interests should direct the treatment of amputations.
The goals involved in the treatment of amputations of the upper extremity include the following [1, 2] :
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Preservation of functional length
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Durable soft-tissue coverage
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Optimal sensation in the residual limb
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Prevention of symptomatic neuromas
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Prevention of adjacent joint contractures
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Early return to work
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Early prosthetic fitting
These goals apply differently to different levels of amputation.
Treatment and management of amputations can be challenging and rewarding. It is imperative that the surgeon and the patient establish treatment goals that optimize function and rehabilitation, keeping in mind the individual's specific goals and needs. Whereas replantation may be technically feasible in some clinical scenarios, it is vital to consider the expected postoperative course and function of the replanted digit. Often, a replanted digit or limb has complications (eg, infection, stiffness, or need for additional procedures) that could result in poorer functional outcome and greater financial cost due to lost wages, prolonged hospitalization, and additional therapy.
Indications
Trauma
Amputations can result from traumatic injury from multiple mechanisms. The mechanism of injury is vital to consider in managing an amputation, in that crush injuries, sharp lacerations, high-energy twisting, and avulsion injuries all create a spectrum of injury to the soft tissue. Exposure to contamination, including industrial machines and environmental contamination (eg, barnyard, aquatic), to electricity, or to temperature extremes is also important to consider. [3, 4]
One of the main goals in managing mangled digits with associated fractures and nerve or vascular injuries is to optimize function of the hand. In some clinical scenarios, the patient may have better future function with amputation than with reconstruction because of the degree of damage to the amputated segment. In the setting of amputation, many have as their goal an “acceptable hand,” understood as one with near-normal length, near-normal sensation, and a functioning thumb. [5] However, each patient may have additional personal goals for hand function that are important to consider on an individual basis.
Infection
An important specific clinical presentation to recognize is the potential for devasting consequences after human bite wounds to the hand. Often, these are deeply penetrating injuries, especially the tooth-knuckle injury, where a small wound belies a deep wound with intra-articular extension and an associated high risk of serious complications (eg, tenosynovitis, septic arthritis, osteomyelitis, and severe stiffness). Amputation may be required in as many as 18.0% of these injuries. [6]
Hand infection in diabetics is another limb-threatening condition that is both underappreciated and challenging to treat. Inadequate treatment can result in long-term disability, contracture, amputation, and even death. Most cases begin as a neglected minor wound that then progresses rapidly. Digital amputation is common in the setting of diabetic finger infection because such infection, once established, can be difficult if not impossible to eradicate. Osteomyelitis, ipsilateral upper-extremity dialysis fistula, end-stage renal disease, and vascular disease each have significant independent predictive value for amputation rather than digital preservation. Amputation may be limb- and life-saving. [7, 8]
Vascular conditions
Raynaud phenomenon is episodic vasospasm of the peripheral vessels causing color changes in the digits, often with associated pain and paresthesias. It can occur in response to cold or stress. Raynaud phenomenon may be either primary (idiopathic) or secondary to connective-tissue diseases (eg, systemic sclerosis), extrinsic vascular obstruction (as in thoracic outlet syndrome), medications, chemicals (eg, ergotamine and vinyl chloride), vibration exposure, and hematologic hyperviscosity states.
In cases of secondary Raynaud phenomenon, there can often be ischemia of the fingers (and toes) leading to ulceration. This may progress to gangrene necessitating amputation when other treatment options to manage the vasospasm have failed. In such cases, amputation may be highly effective for pain relief. [9, 10]
Hemodialysis is a common risk factor for ischemia of the upper extremity, and amputation is a common sequelae. [1] Studies have shown that at present, the best management of dialysis-associated steal syndrome is distal revascularization with interval ligation, which involves ligating an artery distal to the fistula and subsequently forming a bypass. [11]
Finger ischemia in hospitalized patients can occur in many contexts, including in association with the presence of arterial lines and the use of vasopressor medications (eg, phenylephrine and norepinephrine). Despite appropriate treatment with anticoagulant or antiplatelet agents, progression to amputation can occur. Frequently associated conditions include mechanical ventilation (37%), diabetes (34%), peripheral arterial disease (32%), dialysis dependence (31%), cancer (24%), and sepsis (20%). As many as 5% of these patients with finger ischemia ultimately require finger amputation. [12]
Additional clinical situations that may be managed with elective amputations include tumor extirpation, vascular insufficiency, infection, and congenital malformation.
Contraindications
Amputation in the upper extremity is contraindicated when the patient's outcome can be improved with limb salvage.
Technical Considerations
Anatomy
The basic skeleton of the wrist and hand comprises a total of 27 bones. The hand is innervated by three nerves—the median, ulnar, and radial nerves—each of which has sensory and motor components. The muscles of the hand are divided into intrinsic and extrinsic groups.
The hand contains five metacarpal bones. Each metacarpal has a base, a shaft, a neck, and a head. The first metacarpal bone (thumb) is the shortest and most mobile. It articulates proximally with the trapezium. The other four metacarpals articulate with the trapezoid, capitate, and hamate at the base. Each metacarpal head articulates distally with the proximal phalanges of each digit.
The hand contains 14 phalanges. Each digit contains three phalanges (proximal, middle, and distal), except for the thumb, which has only two. To avoid confusion, each digit is referred to by name (thumb, index finger, long or middle finger, ring finger, and small or little finger) rather than by number.
Important anatomy to consider in performing digital amputations includes the digital nerves, the digital arteries, the flexor digitorum profundus (FDP), the flexor digitorum superficialis (FDS), the extensor tendons, the collateral ligaments, the volar plate, the dorsal capsule, and the components of the nail.
When amputations are performed at various levels, it is important to understand the critical anatomy so as to optimize resulting function. The flexor tendons are located on the volar aspect of the finger, and the extensor tendon dorsally. Each joint is stabilized by the radial and ulnar collateral ligaments, with secondary support from the volar plate and dorsal capsule. The digital neurovascular bundles are on the radial and ulnar borders of the digit between the Grayson and Cleland ligaments.
For more information about the relevant anatomy, see Hand Anatomy.
Outcomes
Charpentier et al retrospectively evaluated long-term quality of life and functional outcome in 28 patients who underwent digital replantation after amputation (minimum follow-up, 2 y; mean, 4.6). [13] Total active range of motion (ROM), grip, and pinch strength were assessed; functional outcomes were evaluated; and occupational status and daily activities were reported. Mean total active ROM was 42% of the contralateral healthy side. Mean grip and pinch strength were 80% and 65%, respectively. Fusion did not significantly influence active mobility. Of the 28 patients, 77% returned to the same job, and 75% experienced cold intolerance.
Lafosse et al retrospectively studied surgical outcomes in 13 very young children (mean age, 2.9 y; range, 1.1-5.7) who underwent finger replantation (15 fingers) after traumatic amputation. [14] The authors evaluated everyday life activities, pain and cold tolerance, total active ROM in patients with successful replantation, and growth disturbance. The overall success rate was 47%, with a 67% rate of major complications. Venous ischemia developed in 86%. After surgery, the hemoglobin level decreased by more than 2 g/dL in six patients, and blood transfusion was necessary in two. At the last follow-up, patients with successful replantation had a mean total active ROM of 72%.
Shaterian et al performed a quantitative review and meta-analysis of 36 studies with the aim of identifying predictors of digit survival following replantation. [15] Factors found to influence replant survival included number of venous anastomoses (zero vs one vs two), number of arterial anastomoses (zero vs one vs two), and mechanism of injury (sharp cut vs blunt cut vs avulsion vs crush). Factors not found to be significantly associated with survival included age, sex, zone of injury, digit number, tobacco use, ischemia time, method of preservation, and use of vein graft.
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In performing an index ray amputation, a dorsal longitudinal incision over the index metacarpal is used in conjunction with a circumferential skin incision at the midproximal phalangeal level. The skin is intentionally left long distally to avoid deficiency, which could result in a web-space contracture.
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The principles of a central ray amputation include removal of the injured finger at the metacarpal base, correcting the rotational deformity, closing the space between the 2 adjacent unamputated fingers, and achieving a satisfactory appearance of the hand.This illustration depicts 1 of 2 techniques that have been described regarding central ray amputation. The procedure involves the transfer of the index finger ray onto the third metacarpal base for the middle finger and the small finger to the ring metacarpal base. The disadvantages of the ray transfer procedure are the requirement for postoperative immobilization and the risk of nonunion.
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The second central ray amputation technique involves removing the involved finger at the metacarpal base. The disadvantages of this technique are eventual widening of the web space and rotational deformity of the digit. The risk of these complications can be minimized by repairing the deep transverse intermetacarpal ligament and using a threaded Kirschner wire (K-wire) to secure the second to the fourth metacarpal.
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The technique of central ray amputation involves the use of a circumferential incision at the midproximal phalanx in conjunction with a dorsal longitudinal incision. The dorsal incision is extended through the extensor. The periosteum is scored at the level of the metacarpal base.
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In performing a central ray amputation, the dorsal incision is performed in a tennis racket configuration.
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The volar incision is completed in the shape of a wedge to facilitate closure without a dog ear.
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The dorsal incision is extended through the extensor. The periosteum is scored at the level of the metacarpal base.
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With a central ray amputation, the metacarpal is transected at its base. The hand is then supinated and the flexor is divided.
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The flexor tendon is divided and allowed to retract proximally.
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The metacarpal base is transected with a sagittal saw.
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The amputated central ray is shown here.
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The proper digital nerves and arteries to the adjacent fingers are preserved from the common digital neurovascular bundles.
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The neurovascular bundles are divided proximally to avoid neuroma formation at the skin incision.
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The deep transverse metacarpal ligaments are identified on either side of the volar plate of the involved finger at the metacarpophalangeal joint. In transecting the deep transverse metacarpal ligaments, it is essential to preserve enough ligament to attach to each other to minimize gap formation and rotational deformity.
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The deep transverse metacarpal ligaments are repaired with 2-0 Ethibond nonabsorbable sutures.
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The gap is compressed, and transverse Kirschner wires (K-wires) are placed through the metacarpals on either side of the ray amputation. Threaded K-wires can help resist the sliding of the metacarpals on the K-wires like an accordion.
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The threaded Kirschner wire can help to prevent rotational deformity.
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Active motion is begun early, and the Kirschner wires can be removed at 6 weeks. This technique can be applied to ray amputation of both the middle and ring fingers.
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In performing a central ray amputation of the ring finger, the deep transverse intermetacarpal ligament can be repaired to avoid the need for metacarpal transfer.
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The procedure of small finger ray amputation is performed through a tennis racquet incision.
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When the thumb tip has been amputated, replantation can provide the patient with the best return to function even if interphalangeal joint fusion is required.In the event that replantation cannot be performed or is unsuccessful, minimal bone shortening should be performed to provide a smooth bone end over which to close the skin. In fact, the bone should not be removed only to obtain primary skin closure. A volar rectangular advancement flap (Moberg) should be used to provide soft-tissue closure and preserve thumb length.
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The volar advancement flap is raised as a rectangle to include both neurovascular bundles to the metacarpophalangeal crease of the thumb and is advanced in the distal direction.
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The Moberg flap can be used to close 1- to 1.5-cm defects. If the amputation level is at or distal to the distal interphalangeal joint, the patient should not experience much functional loss.
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The Moberg flap can allow for length preservation and coverage of the thumb tip with sensate skin because it contains both neurovascular bundles.
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If the patient's amputation level is proximal to the interphalangeal joint, reconstruction with toe transfer should be considered. If the amputation is at the carpometacarpal level, pollicization can be considered.
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This patient had a digital nerve neuroma (outlined in marker) following revision amputation. He had point tenderness over the neuroma. The skin and neuroma were removed.
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The neuroma is dissected, and a traction neurectomy is performed.
