In the rare condition where the greater part of the metacarpus is destroyed, and yet carpal joints are uninjured, a most useful artificial band, preserving the movements of the wrist, may be fitted on; and as much as possible should be saved, but in cases of injury, where the carpus is opened and the hand irreparably destroyed, the question arises, Where ought amputation to be performed? To this we answer that there appears no conceivable advantage to be gained by leaving all or any of the carpal bones. If successful, it would result only in the retention of a flapping joint, unless from there being no tendons to act upon it, except the tendon of the flexor carpi ulnaris attached to the pisiform, and there are several risks it would run in the inflammation of all the carpal joints, and the almost certain spread of this inflammation to the bursa underneath the flexor tendons, beyond the annular ligament, and up the arm among the muscles.
Amputation at the Wrist-Joint.—This is an operation by no means frequent, and it has the advantages of preserving a long stump, and retaining the full movements of pronation and supination, in cases where the radio-ulnar joint is sound and uninjured, but in practice it is often found that fibrous adhesions limit to a great extent the motions of the two bones on each other, specially in those cases where the radio-ulnar joint has been diseased or injured.
Another advantage is the extreme ease with which disarticulation may be performed on emergency, no saw being required, and the ordinary bistoury of the pocket-case being quite sufficient for cutting the flaps.
Operation.—By double flap. An incision ([Plate IV.] fig. 3) on the dorsal surface, extending in a semilunar direction from one styloid process to the other, will define a flap of skin only, which must be raised; the joint must then be opened by a transverse incision, and a long semilunar flap of skin and fascia should be shaped ([Plate IV.] fig. 4) from the palm. Disarticulation is facilitated by the surgeon forcibly bending the wrist when he makes the transverse cut, and it will be found easier to shape the palmar flap from the outside by dissection, than to do it by transfixion after disarticulation, on account of the prominence of the pisiform on the inner side of the palm.
Fig. iii. [27]
Fig. iv. [27]
In the thin wasted wrists of the aged, or in any case where the skin is very lax, this amputation may be very easily performed by the circular method. While an assistant draws up the skin as much as possible, the surgeon makes an accurate circular incision through the skin, about an inch below the styloid processes, just grazing the thenar and hypothenar eminences. Another circular sweep just above the pisiform and unciform bones divides all the soft textures, after which the joint may be opened, and, if necessary, the styloid processes cut away with saw or pliers.
Amputation by a long single flap, either dorsal or palmar, may be rendered necessary by accident. The palmar one of the two is preferable; indeed, rather than trust for a covering to the thin skin of the back of the hand, with its numerous tendons, it is better to amputate an inch or two higher up through the fore arm.