This operation is very frequently required to remedy painful and unhealed stumps, the result of amputations lower down, specially those in which the long posterior flap from the muscles of the calf has been used. In the above amputation the patient will not be able to rest the weight of his body on the face of the stump, but by putting the limb into a well-padded case with soft rounded edges, the weight might be borne partly on the sides of the stump, and partly on the lower edge of the patella; and the patient will be able to walk with great comfort, preserving the use of his knee-joint.
Amputation at the Knee-joint.—This "relic of ancient surgery," as Mr. Skey calls it, has been revived only of late years, and seems in certain cases to be a justifiable and successful operation.
Practised by Fabricius Hildanus and Guillemeau in the sixteenth and seventeenth centuries, it had fallen into disuse till revived by Hoin, Velpeau, and Baudens, on the Continent, Professor Nathan Smith in America, and Mr. Lane in London.
It is not possible that this operation can be at all frequent, since the cases in which it is applicable are comparatively rare; for, to be successful, the following conditions are essential:—1. That there be abundant skin in front of the knee-joint to make a long anterior flap; 2. That the patella and articular surface of the femur are healthy. These conditions at once exclude nearly every case of disease or accident. If the joint is diseased some amputation through the thigh must be attempted; if injured, and the front of the knee is safe, it may very likely be possible to amputate below the knee. Hence this operation may be useful in cases where, for malignant disease, the whole tibia requires removal, and yet the knee-joint is sound, or for gunshot injuries, in which the tibia is splintered but the soft tissues comparatively uninjured.
Operation.—A long anterior flap should be cut with a semilunar end ([Plate II.] figs. 6, 7), extending as far as the insertion of the ligamentum patellæ. This flap, including the patella, should be thrown up, the joint cut into, and a short posterior flap made by transfixion.
It is important to retain the patella, if possible, as it fills up the hollow between the condyles; it sometimes becomes anchylosed, but in other cases it remains freely mobile, and adds to the value of the stump.
Professor Pancoast has practised an amputation at the knee-joint by three flaps, performed entirely by the scalpel, which, he says, results in a good stump. One flap, the anterior one, is longest and semilunar in shape, its convexity passing three inches below the tuberosity of the tibia; the other two are much smaller, and postero-lateral.[43]
Advantages.—The bone is not cut into at all, there is a free drain for matter, no tendency to retraction of the flaps, and the weight of the body is borne on skin previously habituated to pressure.
The statistics seem to be favourable: out of 55 cases, Continental, American, and English, 21 died, a mortality of 38 per cent., while in a table of 1055 cases of amputation of the thigh, 464 died, being a mortality of 44 per cent. In some of the American cases the articulating extremity of the femur seems to have been removed, as in the following operation:—
Amputation through the Condyles of the Femur.—In the London and Edinburgh Journal of Medical Science for 1845, Mr. Syme advocated a method of amputation through the condyles of the femur as specially suitable in case of diseased knee-joint. Amputation at this spot has certain advantages:—1. The shaft of the bone being untouched, there is no injury of the medullary cavity, and hence no fear of inflammation of its lining membrane. 2. There is less risk of exfoliation, the cancellated texture of the epiphysis not being liable to it. 3. Being close to the joint, the muscles are cut through where they are tendinous, thus very much diminishing the risk of retraction and consequent protrusion of the bone. 4. A large broad surface of bone is left to bear the weight of the body, and one which, like the ankle-joint stump, will round off and afford a comfortable pad over which the skin of the flap will freely play.