Partial Hand Amputation: Surgical Management

Edward A. Athanasian MD, FAAOS

Mark E. Puhaindran MBBS, MMED, MRCS, FAMS

Dr. Puhaindran or an immediate family member serves as a board member, owner, officer, or committee member of the Singapore Society for Hand Surgery. Neither Dr. Athanasian nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

ABSTRACT

Partial amputation of a finger, ray amputation, multiple ray amputation, and complete hand amputation may be required to treat patients after traumatic injury, infection, or in the setting of malignant bone and soft-tissue tumors. It is helpful to be familiar with the indications for amputation, surgical techniques, outcomes, potential pitfalls, and complications.

Introduction

Amputations of fingers or portions of the hand may be required in the treatment of traumatic injury, infection, and tumor. Each patient has a unique clinical scenario, and treatment should be individualized to that patient and the injury or condition. A well-performed amputation may maximize patient function and appearance. This in turn may have a major effect on the patient’s self-perception, socialization, and work capacity. In this chapter, we review the surgical techniques for different types of partial hand amputations, and look at recent developments that may help improve outcomes.

Single Ray Amputation

General Considerations

Single ray amputation is most commonly done for the treatment of infection, traumatic injuries, and, less frequently, malignant bone and softtissue tumors. Deficits produced by trauma can be limited to the affected digit or can extend more proximally into the metacarpus or the hand. Similarly, the surgical deficits that remain as a result of the oncologic requirements of resection or even infection control are sometimes unique and must be taken into consideration in surgical planning for definitive amputation and reconstruction. The status of the soft tissues and the need for coverage also must be considered. Fillet flaps and “spare parts” from distal amputated parts or adjacent digits can be extremely helpful in achieving wound closure or coverage.¹

Index and small finger ray amputations are done by transecting the base of the metacarpal distal to the extensor carpi radialis and extensor carpi ulnaris, respectively. The middle ray is most commonly transected at the base of the metacarpal, with or without index ray transposition.² The ring finger ray is most commonly disarticulated at the carpometacarpal articulation, with the anticipation that the small finger ray base will migrate to the midline over time. Intermetacarpal ligament repair or reconstruction is critical to reduce the gap between digits as well as rebalance the adjacent digits following central ray amputation, and will improve cosmesis. The authors of this chapter prefer a middle ray amputation without transposition. Intermetacarpal ligament repair or reconstruction also avoids the risk of contamination of adjacent rays when the procedure is done because of malignancy.³

Outcome Considerations

When possible, it is imperative that the functional and cosmetic deficits produced by ray amputation be carefully reviewed with the patient before the surgical procedure. Emotional and psychological considerations should be addressed and expectations defined. Pictures demonstrating the anticipated result and appearance are helpful. Speaking to, or meeting with, an individual who had a ray amputation can be extremely beneficial. In some instances, psychological counseling is appropriate.

Neuroma at the transection site of the digital nerves is expected after all procedures. Most commonly, these neuromas are not particularly uncomfortable, with the exception of the index ray where painful neuromas occur in approximately 70% of patients. There is no widely accepted treatment method to reduce the risk of a painful digital neuroma after a ray amputation, and techniques to address painful neuromas are discussed later.

Grip strength is diminished by approximately 30% after ray amputation, although there can be great
variation.²^,³ The routine reduction of grip strength should be discussed in advance with patients to provide realistic expectations. Patients commonly adapt well to this deficit.

The appearance of the hand after a well-done elective ray amputation can be excellent. Patients should be reassured preoperatively that the deficit of a single ray is not routinely noticed in human interactions, unless fingers are counted.

Preferred Techniques of This Chapter’s Authors

Index Ray Amputation

In an index ray amputation, the dorsal incision is made and the flaps are elevated. The incision may be longitudinal (preferred) or a long V-flap. The extensor tendons are then transected, and interosseous muscles are mobilized extraperiosteally. Bone transection is performed distal to the insertion of the flexor carpi radialis.

For the volar incision, additional skin is taken radially when possible to facilitate closure. The V-incision is incorporated with a volar Bruner incision, which may need to be trimmed at final closure. Digital vessels are identified proximally, cauterized, and then transected. Digital nerves are identified, anesthetized with a local anesthetic, and transected. Flexor tendons are then transected, and the intermetacarpal ligament between the index ray and the middle finger ray is transected. The ray is rotated, and the remaining intrinsic musculature is transected. Skin is closed using nylon suture with attention to the distal radial flap first, followed by dorsal and palmar closures (Figure 1).

Middle Finger Ray Amputation

A middle finger ray amputation is similar to an index ray amputation. The proximal metacarpal is transected at the base of the diaphysis distal to the carpometacarpal ligaments. After removal of the ray, the intermetacarpal ligament is repaired using nonabsorbable suture or reconstructed using the A-1 pulley of the index and middle rays (Figure 2).

Ring Finger Ray Amputation

Ring finger ray amputation is similar to a middle finger ray amputation with the exception of routine disarticulation of the base of the ring finger metacarpal from the carpometacarpal joint. Care must be taken to avoid injury to the deep palmar arch and deep motor branch of the ulnar nerve, which are palmar to the base of the ring finger metacarpal and thus easily injured. Intermetacarpal ligament repair or reconstruction is important to adjust the balance of the small finger and for cosmesis. Over time, the base of the small finger metacarpal migrates radially to help reduce the defect produced by ring finger ray amputation (Figure 3).

Small Finger Amputation

Small finger ray amputation is entirely analogous to index ray amputation with similar incisions and skin flaps. Care must be taken to plan the ulnar-sided skin flap to facilitate closure. The bone is transected distal to the insertion of the extensor carpi ulnaris (Figure 4).

Alternative Surgical Techniques

Transposition of the index ray to the base of the middle ray is a well-accepted reconstruction technique after middle ray amputation. This broadens the first web space slightly and can reduce the tendency for index ray pronation after intermetacarpal ligament repair or reconstruction when transposition is not done. This procedure requires osteotomy of the index metacarpal base and open reduction and internal fixation of the index metacarpal diaphysis to the middle finger metacarpal base. Additional surgical time and risks of malrotation, nonunion, hardware removal, and theoretic expansion of the field of contamination (in the setting of malignant tumor resection) must be taken into consideration if transposition is being considered.

Rehabilitation

Bulky, soft compressive bandages are applied at the time of surgery. The digit range of motion is encouraged to the extent allowed by the level of pain, particularly metacarpophalangeal joint flexion and proximal interphalangeal joint extension. Supervised digit range of motion should be initiated between the first and second postoperative weeks. Sutures remain in place for 2 to 3 weeks. Recovery of range of motion should be the early emphasis of therapy. At week 6, strengthening is initiated. Palmar wound desensitization may be required in the first 3 months, after which incision-site sensitivity typically decreases. Full activity is allowed at 3 months, with continued improvement in strength and function expected for more than 1 year after surgery. Routine discussion of psychological well-being is incorporated into early postoperative physician visits.

Managing Complications

The management of complications should be considered at the time of surgery. Besides painful neuromas, other complications following single ray amputation include digit mal-alignment. To avoid this, digit alignment in extension and flexion must be critically assessed after intermetacarpal ligament repair and, particularly, reconstruction. It is possible to pronate radial-sided digits and supinate ulnar-sided digits during this repair. If done, this will affect the appearance, and could impair function.

Nonunion or malrotation after digit transposition will require additional intervention in the form of bone grafting or surgical correction of rotation.

Double Ray Amputation

General Considerations

Double ray amputation may be required for patients with major hand trauma, those with large tumors involving single rays that encroach on the adjacent ray, or in patients in whom a tumor is located in the space between individual rays. In some radiosensitive lesions, preoperative radiation can be considered in an attempt to reduce the size of the tumor. If adequate size reduction is achieved, it may be possible to convert a planned double ray amputation into a single ray amputation.

FIGURE 1 A, Clinical photograph of a liposarcoma involving the first web space. B, Axial MRI showing the lesion extending from the thumb metacarpal radially to the middle finger metacarpal ulnarly. The palmar barrier is the adductor pollicis. The dorsal disease fungating through the skin. C through J, Surgical photographs. C, The dorsal incision incorporates skin resection at the area of the fungating lesion, with a plan for an index fillet flap. D, The volar incision incorporates a fillet flap incision. The volar wrist veins are marked for a possible donor graft. E, A fillet flap is raised, and the radial dissection includes thumb metacarpal periosteum. F, Palmar dissection is done palmar to the adductor pollicis to allow adequate resection margin. The thumb is rotated radially to facilitate exposure. G and H, Dorsal views of the rotated thumb, fillet flap, and resection specimen. I, Volar appearance of the hand after closure, medial collateral ligament repair, and pinning. J, Dorsal appearance of the hand, with closure facilitated with a fillet flap.

FIGURE 2 A, Illustration of a middle finger ray amputation. B, Clinical photograph of a large proximal phalanx tumor that required ray amputation. Surgical photographs of the volar incision (C) and the dorsal incision (D).

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