eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity

Wrist and Forearm Amputations

Author: Scott G Edwards, MD, Assistant Professor of Orthopedic Surgery, Georgetown University; Consulting Surgeon, Department of Orthopedic Surgery, Greater Metropolitan Orthopaedics
Coauthor(s): A Lee Osterman, MD, Director of Hand Surgery Fellowship, Director, Philadelphia Hand Center; Director, Professor, Department of Orthopedic Surgery, Division of Hand Surgery, University Hospital, Thomas Jefferson University
Contributor Information and Disclosures

Updated: Apr 20, 2008

Introduction

Amputations of the upper extremity largely follow the same basic principles as those of any amputated limb, some of which are covered in this article. However, the primary purpose of this article is to highlight the special considerations involved in acquired amputations at the wrist and forearm (below the elbow).^{1,2,3 4,5} Discussions of amputation at or above the elbow, as well as the various hand and digital amputations, are reserved for a separate article (see Elbow and Above-Elbow Amputations). Although acquired amputations in children are discussed because this group of patients deserves special consideration, congenital limb amputations and deficiencies are beyond the scope of this article.

History of the Procedure

Amputation remains one of the oldest surgical procedures. Archeologists have uncovered evidence of prehistoric people with amputations, both congenital and those acquired from surgery or trauma. While the procedure has evolved significantly since the days of quickly severing a limb from an unanesthetized patient and dipping the stump in boiling oil to achieve hemostasis, it was not until World Wars I and II that modern ideas of amputation and prosthetics developed. Particularly within the last 3 decades, prosthetic research and rehabilitation engineering centers supported by federal funding have disseminated new information regarding biomechanics and prosthetic design. With the advent of physical and rehabilitative medicine, surgeons now realize that the care for the person with an amputation does not end with removal of sutures.

Problem

The surgeon faces many challenges over the course of treatment of the individual with an amputation. As with any potential amputation, the surgeon must decide the salvageability of a limb; this decision is often made quickly in cases of trauma or sepsis. Once the decision to amputate has been made, the level of amputation must be determined. Knowledge of the functional limitations of amputation levels and prosthetic designs, as well as the patient's emotional, physical, and vocational background, must be carefully considered. This is especially true with the upper extremity. As a result, the surgeon walks a tightrope. Preservation of length in the upper extremity is paramount, but not at the cost of lost stump viability, appropriate bone coverage and padding, and optimal prosthetic fitting.

The surgery itself has its own risks of anesthesia and cardiovascular collapse as well as early postoperative infections and pulmonary embolism. Later, and perhaps more specific to individuals with amputations, are occurrences of joint contractures, phantom limb pain, neuroma formation, stump breakdown, and, in children, bony overgrowth.

Individuals with amputations should undergo comprehensive physical and emotional rehabilitation. A person with an amputation is a patient for life. Close coordination with a team of specialists in physiatry or rehabilitative medicine, prosthetist, physical therapist, and psychologist is ideal. Unfortunately, with shrinking medical reimbursements and funds to support such endeavors, the surgeon is often left to direct all rehabilitative efforts alone. This is a formidable task for anyone, especially for a surgeon who frequently has no training, experience, or interest in the area.

The following are major goals of amputation surgery in the upper extremity:

• Preservation of functional length
• Durable coverage
• Preservation of useful sensation
• Prevention of symptomatic neuromas
• Prevention of adjacent joint contractures
• Controlled short-term morbidity
• Early prosthetic fitting, when applicable
• Early patient return to work and play

Frequency

The true frequency of acquired amputation of the wrist and forearm is unknown. Published estimates of amputated limbs, including those of the upper extremities, vary significantly. Prevalences of 350,000-1,000,000 persons with amputations and annual incidence of 20,000-30,000 new amputations have been cited.

Etiology

See Clinical.

Presentation

Incidents of chronic ischemia, such as in persons with diabetes or peripheral vascular disease, occur less often in the upper extremity than in the lower extremity. However, revascularization efforts in this situation are less successful, and frequently the decision is made to proceed to amputation. Chronic ischemic injury begins distally and usually progresses proximally to more viable tissue. For this reason, the extent of ischemic injury may not be appreciated fully soon after the initiation of clinical changes.

In individuals with chronic vascular insufficiency, patients remain quite functional for many years despite intermittent reports of mild pain with activity or cold intolerance. The only skin changes, if any, may be those of atrophy (shiny hairless skin). For example, patients may present with acute onset of pain in the ipsilateral index and long digits with no or minimal skin discoloration acutely. Over the course of 24-72 hours, skin usually turns cyanotic, and pain is replaced with decreased sensation. Provided the patient is not acutely ill from sepsis, amputation at this time is discouraged. Patients with severe chronic vascular insufficiency may experience constant symptoms and may be more susceptible to irreversible ischemia.

In persons with chronic ischemia, allowing the extent of the ischemia to declare itself clinically is far preferable. Cyanotic fingers may turn black with time, and more proximal tissue that had been assumed to be viable may follow, with cyanosis observed in the fingers. Once the progression of ischemia has stabilized, plans for definitive amputation may commence. If the level of amputation is in question, specific tests may be performed to assess the viability and healing potential of the tissue.

Thermal burns and frostbite rarely result in amputation more proximal to the hand. However, with extensive injury, amputation may be required. In general, both thermal burns and frostbite injuries should be managed nonoperatively until the extent of the damage can be assessed accurately and the amputation can be performed at the most distal level consistent with good healing. Pyrophosphate nuclear scanning has been demonstrated to be useful in predicting the need for amputation in these situations.

Even in the setting of trauma, the level of amputation may be difficult to determine. Most cases of trauma involve significant avulsion and crush components that leave obvious devitalized tissue exposed.⁷ The complete extent of the injury zone may not be apparent on initial presentation. When in doubt, especially for grossly contaminated wounds, it is wise to proceed with open amputation to allow the wound to declare itself prior to closure over a definitive stump length.

Neglected compartment syndromes in the upper extremities with resulting global ischemia often necessitate amputation. Provided the patient is not septic or otherwise medically compromised, it is preferable to avoid acute amputation for the status of the tissues to be better assessed. Initially, fasciotomies are performed, and provided the patient remains systemically stable, the role of initial debridement should be to remove tissue that is obviously dead. Tissue that is neither contractile nor bleeding should be removed at this time. Tissue that is noncontractile but bleeding and otherwise healthy appearing should be left intact, and fasciotomies should be left open with a sterile dressing that prevents desiccation.

The patient should then return to the operating room within 24-48 hours for a second observation of the tissues, and the tissues should be debrided as described above. This conservative process continues until the tissues have stabilized and the surgeon is convinced that all remaining tissue is viable.

Although labor intensive, this step-by-step conservative debridement ensures that the most minimal tissue has been removed and that the patient is left with maximal function. Even in severe cases when amputation is indicated, this stepwise process dictates the level of amputation and ensures maximum length rather than arbitrarily guessing at the level, which may be inappropriately long, resulting in failure of healing, or inappropriately short, resulting in decreased functional potential. However, the step-by-step process is contraindicated in patients with systemic sepsis, renal compromise secondary to disseminated myoglobin, or another critical illness in which the patient cannot sustain multiple surgeries.

Indications

Irreparable loss of the blood supply of a diseased or injured upper extremity is the only absolute indication for amputation regardless of all other circumstances. Severe peripheral vascular disease, traumatic injury, thermal and electrical injury, and frostbite commonly require amputation.^6,8 Not only has the part been rendered useless, but it is also a threat to the life of the individual because the toxic products of tissue destruction are disseminated systemically. It is important to remember that no injury severity score exists as a guide for severe upper-extremity trauma. Much of the decision-making is left to the judgment of the surgeon.

Likewise, in individuals with systemic sepsis, amputations are necessary to control an otherwise rampant infection. Occasionally, an injury or condition that does not directly affect the vasculature has disabled the upper extremity to the extent that a prosthesis would be functionally superior to sparing the limb. An indication for amputation after nerve injury is the development of uncontrolled trophic ulcers in an anesthetic upper extremity. Amputation is indicated rarely in persons with quadriplegia, even if the upper extremities have no residual function. Often the upper extremities help maintain balance while sitting and serve to distribute the forces of weightbearing over a larger area, thus minimizing pressure sores.

In general, amputations in the upper extremity are also indicated for persons with malignant tumors without evidence of metastases. Even after metastases, amputation may be necessary to relieve pain when a neoplasm has become ulcerated and infected or has caused a pathologic fracture. In these oncologic cases, the indications for amputations versus limb salvage procedures are evolving constantly and require individual consideration beyond the scope of this article.

Relevant Anatomy

The distal third of the forearm and wrist lack much of the bulky vascular musculature located more proximally. An envelope consisting largely of capsule, ligaments, tendon, and fascia surrounds the distal radius and ulna. Muscle bellies of the flexor pollicis longus and pronator quadratus may be encountered; however, they provide very little in the way of stump padding. Radial and ulnar vessels are identified at this level under flexor carpi radialis and flexor carpi ulnaris, respectively. The median nerve is located between the volar fascia and flexor tendons, while the ulnar nerve lies under the flexor carpi ulnaris just medial to the ulnar artery.⁹

Special attention should be given to identifying and properly addressing the more superficial palmar cutaneous branch of the median nerve and the dorsal cutaneous branch of the ulnar nerve to prevent painful neuroma formation. Unlike at the level of the median and ulnar nerves and their associated branches, at this level, the radial nerve has fragmented into several branches; some are small filaments, crossing the dorsum of the hand and thumb, and are often difficult to isolate.

In the distal forearm, the anterior and posterior interosseous nerves and vessels may be identified running along their respective courses anterior and posterior to the interosseous membrane toward the elbow. Proximally, the forearm becomes divided into distinct anterior and posterior muscular compartments. These compartments, combined with thicker skin and subcutaneous tissue, create healthier flaps for closure and stump padding. The radial artery courses down the lateral aspect of the forearm, with the superficial branch of the radial nerve in the interval between the brachioradialis and the flexor carpi radialis. The median nerve passes deep to the fibrous arch of the origin of the flexor digitorum superficialis, where it continues distally in the middle of the anterior compartment. Just deep to the median nerve lies the anterior interosseous nerve and artery. The ulnar artery and nerve travel together deep to the flexor carpi ulnaris and flexor digitorum superficialis for most of the forearm length.However, near the elbow, the artery leaves the ulnar nerve laterally and travels toward its bifurcation from the brachial artery just distal to the antebrachial fossa.

For more proximal forearm amputations, care must be taken to preserve the pronator teres, which originates from the medial epicondyle of the humerus and the medial aspect of the coronoid and inserts on the middle third of the lateral radius. Not only do a significant number of essential neurovascular structures pass through or in close proximity to the muscle, but also, if a Krukenberg procedure is being considered, the pronator teres serves as the only motor unit for function.

Contraindications

The only absolute contraindication to amputation is a spared limb or part of a limb that would be functionally superior to its amputation. Many factors regarding the functional potential of a spared limb or part of a limb must be considered, including tactile and protective sensation, range of motion, pain, and the intended purpose of the limb or part.

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