Surgical or Prosthetic Phalangization of Hand Amputations: A Review of Priorities

John F. Connolly, M.D.


The patient with a unilateral hand amputation represents both a challenge to surgical judgment and an unresolved prosthetic dilemma. Much can be done to mitigate the patient's disability, but the amputee frequently ignores "rehabilitation" efforts and becomes one-handed. This report illustrates some of the priorities that must be considered in choosing the rehabilitation approach most likely to be effective for the hand amputee.

Prosthetic Methods

The natural reaction of the upper-limb amputee is to maximize what he has left. The unilateral hand amputee is surprisingly independent despite his loss. With experience he is capable of performing all conceivable activities of daily living using his one good hand, with the long amputation stump as an assist. His functional capabilities are adequate despite emphasis from medical advisors that functional improvement should be his primary goal7. Consequently, to improve this individual functionally, a prosthesis must be convenient to use and must give some significant and evident advantage.

The transmetacarpal amputee usually rejects a standard below-elbow prosthesis. For the patient with all digits lost we have used a partial-hand prosthesis that provides more than a surface for opposition with the remaining stump. Wrist motion can be harnessed to operate the artificial fingers in a way analagous to a flexor-hinge orthosis2,3,6. By using wrist motion to control the terminal device, shoulder harnessing can be eliminated (Fig. 1 ). The wrist-driven partial-hand prosthesis requires adequate wrist motion and an external cable and spring to open and close the hand. Pinch force from this device measures about 1.4 kg (3 lbs.). Our experience has shown that the wrist-driven partial-hand prosthesis is especially effective for an amputee without adequate metacarpals for surgical reconstruction.

Surgical Reconstruction

A disabled hand that can be provided with sensation and functional prehension by reconstructive surgery is superior to any prosthesis1,8. Unfortunately, the surgeon often encounters insufficient residual undamaged hand structure to make reconstructive surgery feasible4. However, the presence of one digit, particularly the thumb, allows construction of an opposition post using pedicle flaps and bone grafts, thus giving the patient's hand a convenient and realistic assist. Our experience includes a patient with one such opposition post constructed 25 years ago (Fig. 2 A and B). This patient developed protective sensation in the past and uses the post daily in handling large objects such as X-ray envelopes. When the patient is carefully selected with consideration for his psychological as well as his functional needs, and when the reconstructive procedure is done expeditiously, the result from such an opposition post can be excellent for the one-digit hand.

When the injury involves all digits and leaves the patient with amputations across the metacarpals, phalangization of the metacarpals9 should be employed to provide the patient a pincer mechanism. Phalangization gives improved prehension which can be complimented significantly by prosthetic restoration, as the following two cases illustrate.

Surgical-Prosthetic Phalangization

The first patient was an 18-year-old man who sustained a transmetacarpal amputation of his right hand when it was caught in a press (Fig. 3-A and Fig. 3-B ). Ten weeks after injury, the stump was revised by excising the second and third metacarpals and capitate bone to phalangize the first and the fourth and fifth metacarpals. A split-thickness skin graft was utilized to cover the web-space opening, creating a pincer mechanism with which the patient was able to apply 0.9 kg (2 lbs.) of force. The objects that he could grasp adequately with this mechanism were approximately the size of a pencil (Fig. 3-C ). To improve his grasp function a prosthetic hand was constructed using an alginate impression of the stump. A socket was laminated using one layer of dacron felt and two layers of perlon stockinette. The thumb and finger units were secured to the socket with a build-up, and four layers of perlon were used for final lamination. The socket was split into two parts for thumb and finger sections, and the fingers were flexed in the position of function. The sockets were trimmed to allow clearance without pinching the skin or impeding motion of the stump. A 4-cm (1 and 1/2 in.) elastic with a Velcro strap was used for suspension of the socket.

Immediately after application of the prosthesis the patient was capable of pinching with 0.9 kg (2 lbs.) of force and of holding objects smaller than 1 cm (0.40 in.). In addition, the prosthesis allowed him to grasp large objects such as a can 7 cm (2.7 in.) in diameter and weighing 680 g (1 and 1/2 lbs.) (Figs. 3-D and 3-E D and E).

The second patient was a 49-year-old laborer who sustained an amputation of all fingers of his left hand, with the very proximal part of his phalanges left intact. An initial attempt to deepen the first web space by soft-tissue Z-plasty did not succeed, and subsequently the index metacarpal was removed for adequate phalangization. Pinch measured between 0.9 and 1.4 kg (2-3 lbs.) and was limited to very small objects. The patient was then fitted with thumb and finger units constructed in the same way as for the first patient. The result was a prompt improvement in stump function and ability to work with large as well as small objects. Because of the nonstandard size of the prosthesis a cosmetic glove could not be utilized, and the patient finally settled on a stretchable cotton work glove to cover the prosthetic fingers (Fig. 4 ).

Discussion

The combination of surgical reconstruction and special prosthesis offered these patients complementary function that would not have been possible with either approach alone. The patients immediately demonstrated better precision pinch as well as ability to grasp large objects that would have been impossible to grasp if phalangization or a prosthesis had been used alone. In addition, using the phalangized metacarpals to power the prosthetic fingers eliminated the need for wrist control and the external attachments of a flexor-hinge orthosis. Pinch with the special prosthesis was 1.4 kg (3 lbs.), or equal to the pinch which the phalangized stump could produce without the prosthesis.

These restorations were thought to be cosmetically better than most partial hands, although still not satisfactory for the specific needs of patients who want a hand with essentially normal appearance. As Sharples7 has pointed out, the upper-limb amputee, especially the individual with a long residual stump, considers cosmesis primary and function very much a secondary matter. Our male laboring patients were especially concerned about the cosmetic appearance of their artificial hands. In contrast to the experience of Pillet5 in France, we discovered that very little serious effort has been made to meet the cosmetic needs of the hand amputee in this country. Function can be improved considerably by a combination of surgical and prosthetic techniques. However, cosmetic needs must be given higher priority; and better methods must be utilized to improve the appearance of devices that we offer the partial-hand amputee, even at the sacrifice of theoretical functional improvement.

Acknowledgment

The special prostheses described in this study were fabricated by Mr. Jim McElheney, Nashville, Tennessee.

Department of Orthopaedic Surgery and Rehabilitation, The University of Nebraska Medical Center, Omaha, Nebraska

References:
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