The next is now hardly ever used here, except in cases where the skin over the patella is destroyed.
Modified Circular at Lower Third of Thigh (Syme's).—Two equal semilunar flaps of skin should be cut ([Plate I.] fig. 20, [Plate III.] fig. 6), one anterior, the other posterior, their convexities being towards the knee. The skin and subcutaneous cellular tissue should be raised from the fascia, and then retracted to a further distance of at least two inches; the muscles should then be divided right down to the bone, on a level as high as they are exposed in front, and as low as they are exposed behind. This allows for the different amount of retraction at the two sides of the limb, and leaves the muscles cut on a level; the whole mass of muscles should then be drawn well up, and the bone exposed, and sawn through at a level about two inches higher than where it was first exposed by the anterior incision through the muscles.
In very weak thin flabby limbs this process may be simplified by just at once including the muscles in the skin flaps, and carefully exposing the bone higher up. In performing the retraction the assistant should be cautioned not to overdo it, lest he strip the periosteum from the bone higher than is necessary. This is very easy to do in the weak limbs of strumous patients, and may cause exfoliation, and greatly delay cure.
Amputation in the middle third of the Thigh.—A very short notice will suffice here. The exact position, shape, and size of the flaps must in every case be modified by the nature of the injury for which the operation is performed, taking the flaps where they can be obtained. As a general rule, a long anterior flap with a short posterior, on the principle described above, should be preferred. In cases where the long anterior cannot be obtained, two equal flaps should be made by transfixion. The flaps should always be antero-posterior, the lateral flaps introduced by Vermale, and indorsed by Chelius and Erichsen, having the great disadvantage of allowing the bone, which is drawn up by the psoas and iliacus, to project at the upper angle.
Supposing the right thigh is to be amputated, the surgeon, standing on the inside of the leg, should raise the skin and muscles of the front of the limb in his left hand, and entering the knife just in front of the vessels, should transfix the limb, the knife passing in front of the bone, and including as nearly as possible an exact half of the limb ([Plate IV.] fig. 19); having by a sawing motion brought out the knife and cut a flap of the required length, the knife is re-entered at the same place, and passing behind the bone, the point must be brought out at the angle on the other side. Both flaps being then held back by an assistant, the bone is cleared by a circular turn of the knife, and the saw applied, the vessels are found cut high up in the inner angle of the posterior flap.
In muscular patients it is often better to make the incision through the skin first and allow it to retract before transfixing; this is slower and not so brilliant looking, but avoids redundancy of muscle.
Amputation at the Hip-Joint.—This operation, exceedingly dangerous from the amount of the body removed, the great hæmorrhage, and the risk of pyæmia, is of comparatively modern invention. Though the proportion of recoveries is at present to that of deaths about one to two or two and a half, it is still a perfectly justifiable operation in many cases of disease and injury.
Like amputation at the shoulder, amputation at the hip has given rise to very many various methods of performance. Under the heads of single flap, double flap, oval, circular, and mixed flap and circular, at least twenty distinct methods have been put on record, and, including modifications, there are thirty-seven or thirty-eight different surgeons who have each their own plan of operation.
The reason of this fearful complexity in its literature depends on this fact, that this amputation has generally been performed for cases of such severe injury of the limb, that no milder amputation was possible, and thus the flaps had to be taken just where the surgeon could get them best. And this will have to be the guiding principle in most amputations at this joint; the surgeon must just cut his coat according to his cloth—get his flaps where and how he can.
In cases, however, where it is possible to have a choice, and to select the flaps, the following is, I believe, both the best and quickest method:—