Hand Amputation

Anatomy and Physiology

The anatomy of the hand and wrist are intricate and essential to competently performing a hand amputation.

Digits

Each digit, except the thumb, consists of 3 phalanges: proximal, middle, and distal, articulating at the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints.[3] The thumb, however, lacks a middle phalanx and has distinct tendon anatomy. The distal aspect of each digit includes a nail plate overlaying the nail bed at the distal phalanx. The main stabilizing soft tissue structures at the metacarpophalangeal and interphalangeal joints include the volar plate, radial and ulnar collateral ligaments, and the joint capsule.[4]

The digital flexor tendons insert at 2 locations: the volar base of the middle phalanx (flexor digitorum superficialis) and the volar base of the distal phalanx (flexor digitorum profundus). These flexors pass through a series of 5 annular pulleys as they course to the distal aspect of the finger (except the thumb, which has 2 annular pulleys and 1 oblique pulley). Dorsally, the digital extensor mechanism consists of the expansion of the extensor digitorum tendons, which ultimately inserts as the terminal tendon at the dorsal base of the distal phalanx. The thumb, however, has a different tendon anatomy. The flexor pollicis longus tendon serves as the primary thumb flexor, inserting into the volar base of the thumb distal phalanx, while the extensor pollicis longus is the primary thumb extensor, inserting into the dorsal base of the thumb distal phalanx. 

Palm and Wrist

The palm comprises 5 metacarpals and their articulations at the carpometacarpal joints, housing the thenar, hypothenar, interosseous, and lumbrical muscles. Proximally, the wrist is formed by 8 carpal bones arranged in 2 rows: a proximal row (scaphoid, lunate, triquetrum, pisiform) and a distal row (trapezium, trapezoid, capitate, hamate). The proximal carpal row articulates with the distal radial articular surface. Adjacent to this is the distal ulna and ulnar styloid. The distal radioulnar joint is the interface between the distal ulna head and the sigmoid notch of the distal radius, which is spanned and stabilized by the triangular fibrocartilage complex. A myriad of ligaments similarly spans the carpometacarpal, intercarpal, and radiocarpal articulations, both volarly and dorsally. At the wrist/proximal palm level, the nine digital flexor tendons pass through the carpal tunnel while the wrist flexors, including the flexor carpi radialis and ulnaris, course adjacent to this area. Dorsally, the extensor tendons of the hand and wrist pass through a series of 6 extensor compartments.

Neurovascular

Neurovascular structures of the hand are arranged in a longitudinal branching pattern.[5] The median nerve courses deep to the flexor carpi radialis tendon and then passes through the carpal tunnel, with recurrent motor and palmar cutaneous branches. The ulnar nerve travels through the Guyon canal deep to the hypothenar eminence with sensory and deep motor branches. The median and ulnar nerves form each finger's radial and ulnar digital sensory nerves as they course distally. More dorsally, the superficial branch of the radial nerve and the dorsal sensory branch of the ulnar nerve span the radial and ulnar aspects of the hand, respectively. The primary vascular contributions to the hand emanate from the radial and ulnar arteries. These form the superficial and deep palmar arches that branch to form the common and proper digital arteries.      

Indications

A hand amputation may be deemed appropriate or necessary due to various conditions and pathologies, including:

• Severe trauma not amenable to replantation
• Dry or wet gangrene
• Infection
• Severe contractures or other deformities that substantially impact upper extremity function
• Frostbite
• Malignancies of the hand or digit
• Peripheral vascular disease, particularly when associated with end-stage renal disease requiring dialysis
• Poorly controlled diabetes, with resultant formation of nonhealing ulcers
• Complex regional pain syndrome refractory to other modalities [6]
• Prior unsuccessful replantation.

Contraindications

The primary relative contraindication to a hand amputation is if the patient would likely have a better functional outcome if the hand or digit were preserved.[7] Suitable alternative treatments may be necessary to achieve this.  

Equipment

The equipment utilized to perform an amputation of the hand or digit will vary by surgeon preference and the specific procedure to be performed. However, most distal upper extremity amputation surgeries will employ many of the following instruments:

• Littler scissors
• Adson forceps
• 15-blade scalpel
• Rongeur (small or medium)
• Retractors (eg, Ragnells)
• Oscillating bone saw
• Needle driver
• Sutures (eg, 4-0 or 5-0 nylon, 4-0 vicryl, 4-0 or 5-0 chromic, 2-0 silk)
• Suture scissors
• Tourniquet (18-inch or larger as needed)
• Bipolar electrocautery
• Suction (with neuro tip)
• Irrigation (normal saline)
• Mini C-arm (for intraoperative fluoroscopy)
• Dressing supplies.

Personnel

Several healthcare providers may be involved in caring for a patient requiring a hand amputation. The surgeon performing the procedure is most commonly an orthopedist or plastic surgeon with additional hand and upper extremity surgery training. Less commonly, and depending upon the availability of the specialists above, a vascular surgeon may perform the amputation. Regardless of clinical background, the surgeon will oversee the overall management of the affected extremity from the preoperative through the postoperative phases of care. Additional providers may participate at various points in the treatment process, including:

• Preoperative
  • Emergency medicine physicians, primary care practitioners, and infectious disease specialists may be the first to identify and evaluate hand pathology necessitating amputation. They may refer the patient for surgical consultation. 
• Operative
  • Anesthesiologists provide sedation and regional anesthesia for procedures that require more than local injection alone. A surgical assistant is often helpful during the operation to assist with soft tissue retraction and extremity positioning.   
• Postoperative
  • Wound care team members may provide additional recommendations on appropriate dressings to improve the healing of the amputation site. Hand therapists are vital to rehabilitating the residual limb and guiding the patient through any necessary occupational modifications. Depending upon the location and extent of the amputation, prosthetists may be able to evaluate and fit a patient for a prosthetic device.  

Preparation

Obtaining a comprehensive medical history and performing a thorough physical examination is necessary before performing a hand amputation. The entire medical history should include tobacco, steroids, immunosuppressants, and anticoagulant use, as these can interfere with wound healing and predispose the patient to postoperative infections. Additionally, in those patients with diabetes mellitus, a recent hemoglobin A1c level should be reviewed due to similar wound healing and infection concerns. Any other medical conditions, such as crystalline arthropathies, such as gout and pseudogout, and systemic inflammatory diseases, such as rheumatoid arthritis, that may flare due to surgical amputation should be noted. 

The physical examination should consist of a complete evaluation of the entire upper extremity. While inspecting, palpating, assessing range of motion, and performing a neurovascular assessment, particular attention should be paid to the presence or absence of concomitant infection. If present, the location and extent of infection should be determined for preoperative planning purposes. In addition, the quality of neighboring soft tissues must be determined to identify the boundary of viable, perfused tissue. This is vital for planning the surgical incision, the extent of the amputation needed, and wound closure options. When the viability of any soft tissue is in question, and if amputation is not required emergently, the tissue should be allowed time to demarcate. This entails frequent reevaluations of the area to monitor for advancing areas of necrosis and eventual stabilization of the boundary between nonviable and viable tissue.

Preoperative imaging studies are typically performed. Radiographs of the hand and wrist, as well as the forearm, if a more proximal amputation is planned, should be obtained to evaluate for any additional underlying pathology and to screen for possible destructive bony changes consistent with osteomyelitis. Further assessment with magnetic resonance imaging (MRI), with and without contrast, can be performed to determine the presence and degree of osteomyelitis and abscesses. In patients where a vascular etiology underlies their pathology, a vascular (perfusion) ultrasound should be obtained to evaluate flow rates and the degree of arterial occlusion, as this can influence the decision to amputate and the corresponding level. 

Technique or Treatment

Hand amputations often include 3 main procedures: primary digital amputation, revision (digital) amputation, and wrist disarticulation. While individual steps may vary depending on the specific pathology, tissue quality, and surgeon preference, the following sections outline the principal components of each procedure. Regardless of the procedure selected, the treatment objectives include preserving length, covering the residual digit/upper extremity with sensate tissue, avoiding painful neuromas, and maintaining the function of the proximal joints.    

Primary Digital Amputation

If a digit is deemed unsalvagable, a primary digital amputation can be performed. The patient is positioned supine with the operative upper extremity resting on a hand table. A well-padded, nonsterile tourniquet is then applied to the upper extremity. For a digital amputation, this may be placed at the level of the forearm or proximal to the elbow. A dose of preoperative intravenous antibiotics is often provided prior to incision. The type of anesthesia administered may vary by surgeon (and anesthesiologist) preference. Still, it can include general (endotracheal intubation or laryngeal mask airway), monitored anesthesia care with local injection, or a regional block. The upper extremity is then prepped and draped in the usual sterile fashion. A timeout should be completed to confirm the site, laterality, and procedure.

The extremity is then elevated and exsanguinated using an Esmarch bandage, and the tourniquet is inflated to 250 mm Hg. A circumferential incision around the affected digit is made with a 15-blade scalpel to include the intended region to be amputated, leaving a large, full-thickness volar flap and a shorter dorsal flap (as permitted by the integrity of the soft tissues, being cautious to avoid incorporating any potentially nonviable or infected tissues). Blunt dissection is carried down further through the subcutaneous tissues to expose the extensor mechanism, flexor tendons, and the radial and ulnar digital neurovascular bundles. The volar and dorsal soft tissue flaps are then mobilized. Next, the extensor mechanism is incised transversely proximal to the intended osseous amputation level. The radial and ulnar digital nerves are then carefully dissected from the digital vascular structures, the nerves are pulled distally to expose them, and a neurectomy of each is performed as far proximally as possible (to avoid the formation of a neuroma) with the aid of bipolar electrocautery. Then, the flexor tendons are transversely incised in a fashion similar to the extensor mechanism.

Attention is then turned to the osseous structures. When the pathology allows the preservation of the neighboring joint, a transosseous amputation is performed through the phalanx with an oscillating bone saw, ideally distal to the insertion site of the relevant flexor tendon/extensor mechanism, to preserve an active range of motion at the adjacent joint. However, if the pathology necessitates a more proximal amputation, as in the circumstances to ensure the removal of necrotic or infected tissue, then an interphalangeal or metacarpophalangeal joint disarticulation is performed. This is accomplished by incising the collateral ligaments and the volar plate. Once completed, the digit is amputated and can be sent for pathological analysis if desired. Additionally, intraoperative cultures (typically 3) can be obtained. The wound is then copiously irrigated with normal saline.

The previously established and mobilized volar flap is advanced dorsally over the amputated surface. The lengths of the dorsal and volar flaps are revised to ensure complete coverage. The flaps meet dorsally, ensuring that the final surgical scar is dorsal and that the volar flap provides coverage of the entire distal end of the residual digit. The flaps are then sutured together under no tension with 5-0 nylon sutures. If primary closure is impossible, grafting or other flap techniques can be utilized.[8][9][10][11][12] Ultimately, ensuring adequate soft tissue coverage is of paramount importance. The tourniquet is deflated, and the residual digit and flaps perfusion is assessed. Once confirmed, a dry sterile dressing and a protective splint, if desired, is applied. 

A ray resection can be performed in more extensive pathology, including the entire digit and a portion of the palm or dorsal hand. This entails amputation of the affected digit and the corresponding metacarpal by extending the amputation proximally to the proximal metacarpal metadiaphyseal flare level. The same principle steps as outlined above are otherwise followed. 

Postoperatively, strict upper extremity elevation to better control swelling, active range of motion of the unaffected digits, and avoidance of lifting activities are encouraged. The incision should be carefully monitored for continued perfusion and healing, typically within 2 to 3 weeks for primary closure; this timeline could be prolonged depending upon the specific pathology and patient comorbidities or if grafting techniques are implemented. Once adequate healing has occurred, sutures are removed, and the patient is enrolled in hand therapy to restore the motion and strength of the residual hand.    

Revision (Digital) Amputation

When a digit is traumatically amputated and has exposed bone or tendon, a revision amputation can be considered if the patient is not otherwise a candidate for replantation.[13] This procedure is often performed outside the formal operating room and, more commonly, in the emergency room setting. A tetanus booster (if needed) and a dose of intravenous antibiotics should be administered upon recognition of the injury. Local anesthetic in the form of a digital block is introduced. A digital or forearm-based tourniquet is then applied, and the hand is prepped and draped in the usual sterile fashion. Given the open wound, the antiseptic prep can consist of either a betadine wet prep or a chlorhexidine scrub. The wound is then copiously irrigated with normal saline to remove debris and improve overall visualization.

The amputation site is subsequently explored to assess the extent of injury and damage to the anatomic structures. If lacerated digital nerve endings are visible near the skin level, these are pulled distally, and a neurectomy is performed as far proximally as possible, similar to a primary digital amputation. The exposed tendon is sharply resected with a scalpel, while the exposed bone is resected with a rongeur until it is determined that adequate soft tissue coverage can be obtained. Once accomplished, the wound is again copiously irrigated with normal saline. Soft tissue flaps are mobilized via additional dissection as needed, and the amputation site is closed with 4-0 or 5-0 chromic or other dissolvable sutures. A dry sterile dressing is then applied. 

Postoperatively, patients follow a similar course as described for primary digital amputation. However, if primary closure or grafting/flap coverage is not possible, healing by secondary intention can be pursued. In this case, the initial dressing is left dry and in place for 7 to 10 days, at which time daily soaks in dilute hydrogen peroxide followed by application of a new dry dressing are commenced. This continues until the wound has healed, which is frequently 4 or more weeks.

Wrist Disarticulation

In patients with extensive and severe hand pathology, such as pandigital necrosis or missed and untreated hand compartment syndrome, for whom there is little or no residual hand function, a wrist disarticulation can be performed. With the patient supine and the affected upper extremity on a hand table, a tourniquet is applied to the upper extremity proximal to the elbow, and a dose of preoperative intravenous antibiotics is administered. The types of anesthesia for this procedure are the same as those for primary digital amputation. The extremity is prepped and draped, exsanguinated using an Esmarch bandage, and the tourniquet is inflated to 250 mm Hg.

The subsequent principal procedural steps are similar to those of a primary digital amputation. A circumferential incision is made distal to the radial and ulnar styloids, leaving a large, full-thickness volar soft tissue flap and a shorter dorsal flap to permit eventual coverage of the amputation site. These flaps are undermined for mobilization. Blunt dissection is carried down dorsally to reveal the extensor tendons, dorsal cutaneous branch of the ulnar nerve, and dorsal sensory branch of the radial nerve. Dissection is performed volarly to expose the flexor tendons, median and ulnar nerves, and the radial and ulnar arteries and veins.

All arteries and veins are double-ligated proximal to the amputation site with 2-0 silk sutures and then transected. Neurectomies of all nerves are performed following the procedure for primary digital amputation. The flexor and extensor tendons are transected proximal to the amputation site, and deeper dissection is performed through the wrist capsule to reveal the underlying radiocarpal ligaments. These ligaments are sharply transected to complete the wrist disarticulation. With the hand now removed, the radial styloid may be resected to allow for better contouring of the residual limb. Still, the triangular fibrocartilage complex should be preserved to maintain adequate postoperative pronation and supination. The wound is copiously irrigated with normal saline, and the tourniquet is deflated to evaluate the integrity of the vascular ligation and to obtain overall hemostatic control. Then, the volar and dorsal soft tissue flaps are advanced and closed like a primary digital amputation. A dry sterile dressing is then applied. 

Postoperatively, the patient follows an initial course similar to a primary digital amputation. However, if deemed a candidate once the incision has healed, a prosthetist can be consulted to shape, design, and fit a prosthetic device to the residual limb, including a passive, body-powered, myoelectric, or hybrid prosthetic.     

Additional considerations when performing a hand amputation include:

• A mini C-arm can obtain intraoperative fluoroscopic images to document the amputation and ensure that all intended bony structures have been adequately resected.
• If concomitant infection is suspected, in addition to obtaining intraoperative cultures, it is advisable to start broad-spectrum intravenous antibiotics and consult an infectious disease specialist. The antibiotic regimen will be refined as cultures are finalized. However, prolonged antibiotics may not be necessary if the infection is fully contained within the amputated area. 

Complications

The potential complications following a hand amputation reflect those common to many upper extremity surgeries and those more unique to limb resection procedures.

Phantom Limb or Pain Syndrome

Phantom limb syndrome refers to a sensation that is often tingling but not painful, felt in the region of the amputated part as if it were still present. This is a fairly common experience for many patients with amputations, and treatment typically involves reassurance.

Phantom pain syndrome specifically manifests as neuropathic pain, which can be described as sharp, crushing, burning, or cramping in nature.[14] These symptoms can be managed with neuropathic medications such as pregabalin and gabapentin, peripheral nerve blocks, botulinum toxin therapy, neuromodulation techniques, and surgically with targeted muscle reinnervation.[15][16][17]

Neuroma Formation

A neuroma is a painful mass that results from disorganized remodeling and scarring of nerve cells at the site of nerve transection. The location of the neurectomy performed during surgical amputation, the degree of retraction of the nerve, and the embedding within the muscle all serve to mitigate the risk of postoperative neuroma formation.[18] A symptomatic neuroma may be treated nonoperatively with neuropathic pain medications, antidepressants, anticonvulsants, and topical modalities such as electrical stimulation and slow-release anesthetic patches. Surgical management includes neuroma resection with reconstruction or relocation.[19][20]       

Infection

As with any surgical procedure, postoperative infection is a complication that can have wide-ranging ramifications, leading to potential wound healing issues, abscess formation, or osteomyelitis. Postoperative antibiotics and appropriate wound care can help mitigate this risk.   

Edema

Focal swelling, particularly at the distal aspect of the residual limb, may present early in the immediate postoperative recovery period and potentially lead to increased pain and impaired wound healing. Strict upper extremity elevation is integral to minimizing edema. When the surgical wound has reached an advanced stage of healing, compressive dressings and massage can be incorporated to improve residual swelling further.  

Wound Dehiscence or Delayed Wound Healing  

This may occur due to several different factors, including the aforementioned infection and edema, continued bleeding, and patient comorbidities such as poorly controlled diabetes, underlying vascular pathology, continued use of immunosuppressants and steroids, and tobacco use, among others. Local wound care and potential debridements may be necessary to facilitate wound closure. 

Flap Failure

If flap closure is performed, the tissue may become necrotic prior to healing. Necrosis may result from vasospasm leading to thrombosis at the site of anastomosis. Early recognition and intervention, possibly including leech therapy or decompression of a compromising hematoma, may help minimize the risk of needing revision flap surgery.  

Range of Motion Deficits

Stiffness of adjacent small joints can occur following amputation due to swelling, disuse, and immobilization. Extensor lags of a partially amputated digit may occur if resection is performed proximal to the insertion of the extensor mechanism. In the setting of a wrist disarticulation, resection of the distal ulna can lead to limitations in pronation and supination.

Psychological Impact

Following extremity amputation, patients may experience emotional distress associated with limb loss, a tendency towards isolation, and limitations in their life roles.[21] Counseling services can assist the patient with addressing these issues.  

Clinical Significance

Hand amputations have functional and cosmetic implications that can profoundly impact a patient.[22] The 3 primary functional units of the hand include opposition with the thumb, pinch with the index and middle fingers, and grip with the ring and small fingers.[23] Any 1 or more of these functions can be compromised following an amputation. The impact on a patient's physical, psychological, and social functions is significant, and aesthetic concerns from body asymmetry can compound this. Careful preoperative planning, appropriate surgical techniques, and meticulous postoperative care are necessary to improve patient outcomes.   

Enhancing Healthcare Team Outcomes

The successful management of patients requiring a hand amputation is only possible through a collaborative, interprofessional approach during all phases of care.[24] Physicians, advanced practitioners, nurses, pharmacists, and other health professionals must work together seamlessly to optimize patient-centered care. Surgeons must collaborate closely with rehabilitation specialists to plan for functional outcomes after amputation, ensuring that prosthetics and therapy are customized to meet individual patient needs. Nurses are vital in wound care management, monitoring for signs of infection, and educating patients and families on postoperative care. Pharmacists play a crucial role in managing pain and preventing complications by ensuring the appropriate use of medications, including antibiotics and analgesics.

Coordination among the healthcare team is essential to enhance patient safety and outcomes. Clear communication strategies, such as regular interdisciplinary team meetings and shared electronic health records, are crucial for tracking patient progress, anticipating complications, and adjusting care plans accordingly. Each team member must understand their role and the roles of others to ensure comprehensive and well-coordinated care. This collaborative approach improves patient outcomes and enhances team performance, increasing patient satisfaction and overall care quality.