The hand is a common location for primary and secondary malignant tumors and benign-aggressive lesions. Metastatic disease, although more common in the lower extremity, can also occur in the hand. Examples of primary and secondary malignant tumors, benign-aggressive lesions, and metastatic disease include epithelioid sarcoma, secondary chondrosarcoma, giant cell tumor, and metastatic lung cancer. Adequate ablation and disease-free margins are the primary concern in some of these diagnoses, whereas preservation of anatomy and restoration of function are secondary considerations. Metallic implants for the hand are limited, but microvascular transfers can sometimes obviate the need for amputation.

Phalangeal malignancies, or tumors involving the soft tissue overlying the phalanges, are managed with disarticulation or amputation proximal to the tumor to permit adequate bone and/or soft-tissue margins. In most patients, the healing potential of the hand is excellent. Fish-mouth incisions are useful distal to the metacarpophalangeal joints.⁷ They are easy to design and tend to heal well while preserving some degree of palmar sensitivity. This sensitivity is increased by using palmar-based flaps, which have the advantage of increased sensation, increased skin thickness, and more robust vascularity. The metacarpophalangeal joints do not accommodate fish-mouth incisions; therefore, palmar flaps are more useful. Soft-tissue flaps based on either the radial or ulnar arteries are very serviceable, but only if the tumor resection will allow negative margins. Tumors involving the index ray or phalanges are best managed with ray resection. The pinch function of the index finger is easily taken over by the long finger; therefore, complex reconstruction of the index finger should be critically evaluated. Resections of the distal phalanx of the thumb leave a useful digit and do not require further reconstruction, although prostheses have been made for this resection level, and can aid in hand dexterity. Amputations of the proximal phalanx of the thumb have been managed with microvascular toe-to-hand transfer with good results.⁸ Patients adapt well to the absence of one thumb and do not always require this complex reconstruction. A simpler resection that may allow adequate function is a first web space deepening. This procedure depends on the flexibility of the first carpometacarpal joint and allows some pinch and grasp functions without the need for microsurgery.

More proximal tumors of the metacarpal rays and soft tissues are managed with ray amputation. This procedure removes the ray and soft tissues to the carpal articulation proximally. Multiple rays can be resected at one time to obtain adequate oncologic margins. Preserving two rays may yield an acceptable functional result. Preserving the fourth and fifth rays enables power grip with the involved hand, although pinch grip is sacrificed. Conversely, retaining the thumb and index rays will permit normal pinch grip but limit power grip. The authors of one study described their success with double-ray amputations.⁹ Although functionally inferior to single-ray amputations, the authors reported that key, tip, and tripod pinch could be preserved, and the surgically treated hand was able to assist in bimanual activities. A hand with a lobster claw composed of the first and fifth rays can be useful for moderate pinch and power grip and is functional.
Restoration of the thumb ray by vascular transplant can be functional but should be avoided in cases in which the thenar musculature is resected with the tumor.

For tumors involving the entire hand, tumors that have recurred despite adequate initial surgery, and proximal hand tumors, wrist disarticulation is a viable option. Dorsal and volar flaps work very well. Amputation is performed through the radiocarpal articulation. No benefit is derived from leaving carpal bones, because these can contract into a disadvantageous position. Pronation and supination of the forearm is preserved through the distal radioulnar joint and the forearm musculature. A standard transforearm prosthesis can yield functional results. The ultimate length of the arm with the prosthesis is typically longer than the uninvolved side, but this result produces neither functional nor cosmetic problems as in the lower extremity. Sophisticated multiarticulated myoelectric hands are in development, and the literature suggests that these prostheses may yield greater patient satisfaction and functional results compared with single-joint prosthetic hands.¹⁰

The function regained when an amputation is performed below the elbow but proximal to the wrist (transforearm) is largely dependent on residual limb length and the remaining muscular attachments. Very long residual forearms have nearly full pronation and supination and a large contact area to support a prosthesis. At the midforearm, the pronator quadratus and a portion of the pronator teres are sacrificed, and some pronation strength is therefore lost. The amputation is usually performed with dorsal and volar flaps and can accommodate the suspension of a transforearm prosthesis. The remaining pronator teres and the biceps brachii insertions provide some active rotation of the forearm. When the tumor requires amputation of the proximal third of the forearm, most rotation is lost. Elbow flexion and extension are preserved, and rotation of the forearm is replaced by manipulation at the terminal end of the prosthesis. A Muenster-type prosthesis with epicondylar support is often needed with proximal transforearm amputations. Disarticulation at the elbow can be functionally superior to a very proximal transforearm amputation, because flexion contracture can be problematic and a short residual forearm can preclude prosthesis fitting. However, patients with very proximal transforearm amputation may adapt to grasping objects in the antecubital fossa, as discussed later. Myoelectric prostheses are functional at this level of amputation but tend to respond slowly and are heavy to wear. Researchers reported on a prosthesis with independent finger movement that is still in development.¹¹ The more conventional sling harness prostheses with either active opening or active closing terminal devices tend to be more widely accepted and used. They are extremely durable and therefore spend more time being worn and less time in repair. Many individuals who have undergone transforearm amputation use their residual forearm as a post and their elbow as a vise grip and elect not to wear a prosthesis. As long as elbow flexion is maintained, these individuals can be quite facile at carrying objects in this manner (Figure 2).

Elbow disarticulation is a simple, relatively straightforward upper extremity amputation. Triceps-based or anterior skin flaps are durable and heal nicely. Prosthetic considerations are the same as those for a transhumeral amputation, accepting a limb-length inequality. This result is not usually seen as a significant cosmetic deformity. Prosthesis use following elbow disarticulation is a concern. Prosthetic rejection at this level has been cited at 20% to 50%,^12,13 and recipients required a larger number of prosthetic fittings and low overall activity levels compared with other amputation levels.¹³

Tumors of the elbow or distal arm can be managed with transhumeral amputation. Anterior (elbow flexor) and posterior (elbow extensor) muscle groups can undergo myodesis, and shoulder function is retained. Longer anterior or posterior flaps can be designed to accommodate tumor resection. Function is significantly better in patients whose deltoid insertions are preserved. Amputations of the proximal third of the humerus result in limited function and are essentially equivalent to shoulder disarticulations, with the exception of more natural cosmesis at the shoulder. They can result in muscle contractures secondary to functional muscle imbalance. Prostheses for patients with transhumeral amputations are problematic largely because of gravity. Intimate fit of the residual humerus within the prosthesis is difficult to accomplish, but without it, the ability to move two articulating joints is very challenging. Many prostheses have elbow positions that are set manually, and only the terminal device is dynamic. Myoelectric prostheses were preferred in a survey of traumatic transhumeral amputees.¹³ However, the heavy materials required in their design led to significantly increased neck and ipsilateral limb pain.¹⁴ Direct endoskeletal attachment with osseointegration has been performed and shows great promise¹⁵ but is still experimental.

When an amputation that involves the shoulder girdle is considered, a decision must be made between shoulder disarticulation and forequarter amputation. If the deltoid can be preserved as a flap and the glenohumeral joint is not directly involved, shoulder disarticulation is the procedure of choice. The deltoid is elevated, preserving its posterior neurovascular bundle, and the skin of the axilla is cut transversely, creating superior and inferior flaps. A lymph node dissection can be performed at this time as well, provided the vascular supply to the deltoid is not sacrificed. If the humeral head is not involved, transecting the surgical neck and leaving the head in situ is preferable. This method leaves a more cosmetic shoulder such that wearing a shirt or blouse is easier, more comfortable, and more natural appearing (Figure 3). Flap closure is not compromised by this preservation. Functional prostheses at this level are cumbersome, but some patients find a cosmetic arm to be of benefit.

Forequarter amputation is the ablation of the entire upper extremity. The clavicle, scapula, and arm all are resected en bloc. The deep plane of dissection is the chest wall. Anteriorly based flaps use the pectoralis major as the primary muscle for closure, whereas posteriorly the trapezius is used. The type of flap is often dictated by the location of the tumor. Resection of involved ribs and chest wall can be combined with this amputation.¹⁶ The cosmetic result is a profound slope from the neck to the thorax (Figure 4). This result makes wearing clothes difficult. A static, cosmetic shoulder pad can be fabricated to assist with cosmesis.

Free and pedicled soft-tissue flaps have the potential to modify the level and functionality of upper extremity amputations.^17,18 Soft-tissue tumors may not require bony resection, but higher levels of amputation are often limited by the soft tissue available for closure. If a microvascular surgeon is available, it may be feasible to manipulate soft-tissue flaps to achieve a more functional level of amputation. For several forequarter amputations, the uninvolved forearm of the ipsilateral side has been used for a free muscle and skin transfer in the manner described in one study,¹⁹ and this ingenious fillet flap technique has been found to be of great benefit.

Toe amputations are generally well tolerated without functional deficit or the need for shoe modification. The notable exception to this trend is the great toe, which is important in push-off strength in quick walking and running. If oncologically feasible, it is preferable from a functional standpoint to amputate distal to the base of the proximal phalanx, because this technique will preserve the flexor hallucis brevis insertion and improve stability. If the entire hallux must be removed, a shoe insert and rigid foot plate may be required for ambulation and shoe comfort.^5,6,22

Malignancies that involve the metatarsals can necessitate resection of an entire ray. This procedure entails resection of the metatarsal bones and phalanges to the level of the tarsometatarsal joint (Lisfranc joint) as well as the associated musculotendinous structures. Like phalangeal resections, single-ray resections are well tolerated with excellent cosmetic and functional results. Shoe modification is not necessarily required, although some patients derive benefit from simple measures such as an extra sock or a foam insert. Amputation of the first ray requires special mention. Resection of the entire first ray from the medial cuneiform can cause abnormal gait, medial foot instability, and loss of push-off strength. In this instance, reconstruction with allograft or autograft may be desirable if a segmental resection is possible. Otherwise, a shoe insert and rigid foot plate can improve function.^5,6,23