Excision of the knee-joint: A, semilunar incision; B, Ollier’s incision.
The Knee.
—The knee is generally more accessible for operation than the elbow, as the important structures which should not be disturbed lie grouped upon its posterior aspect. Protection for one of these is protection for all, and the freedom with which the joint may be opened makes it especially easy to do either complete or partial operation. Here the surgeon should endeavor to preserve the epiphyses, especially in children, as they have much to do with the growth and length of the limb. So long as incision is confined to the anterior aspect of the joint it can be made in almost any manner. The usual method is that represented by line A in [Fig. 220], by which a horseshoe flap is raised and the joint interior exposed. Occasionally the direction of the flap is reversed, and it is turned downward rather than upward. In the former case the ligamentum patellæ is divided; in the latter, the tendo patellæ. Whichever way the flap is turned it is made to include the patella, although this bone can be removed at any time. The lateral ligaments being divided, as well as the crucial, and the limb completely flexed, exposure of the joint surfaces is made. It is now possible to do an arthrectomy, a partial exsection or a complete one, according as the disease is more or less extensive. In the complete operation the articular surfaces of the femur and of the tibia are usually removed with an amputating saw. If this be introduced from the front and made to work its way backward the popliteal vessels should be amply protected against possible injury. Here it should be borne in mind that the leg is not constructed in a straight line, but that there is a lateral angle at the knee, as the femurs diverge as they pass upward, and this angle should be imitated in directing the saw and removing the bone end. Again, a slight bend anteriorly will make the limb more useful than one which is absolutely straight. The intent thus should be to give the knee at a slight angle anteriorly and interiorly, and the saw should be manipulated with great care. In a complete operation the patella is also removed. In tuberculous and other septic disease the capsule should be completely extirpated. This offers no difficulty, save at the posterior surface, where it may approach closely to the region of the great vessels.
Various modifications have been practised in these operations. Some open the joint by straight cross-incision with division of the patella, the latter being reunited with tendon or wire sutures. Others have practised a more complicated H-shaped incision, the transverse portion being carried either through the patella or just below it. The line marked B in [Fig. 220] was suggested by Ollier. It is questionable whether any of these methods offer any advantages over the one first described.
After exsection it is desirable to maintain the bone ends in an accurate position if speedy reunion be desired, and for this purpose various methods are in vogue. The bones may be drilled and fastened together with tendon or wire sutures, or ivory nails may be driven in, one on each side, directing them obliquely, so that displacement cannot easily occur, or metal nails may be used for the same purpose. Another plan is to insert two long metal drills, one on either side, which perforate the skin two or three inches above the wound, and are passed downward and toward the other side so as to fix the surfaces, as it were, by a cross-forked arrangement. After two or three weeks these drills may be withdrawn. Fixation of this kind is advantageous, for when complete excision has been practised the surrounding tissues are lax and the parts are not easily held in position by external dressings alone. In a clean case, with careful hemostasis, very little drainage will be required. What is needed can be provided by an absorbable drain passed through the lower portion of the wound on either side. In a septic case it would be well to provide for ample drainage on each side.
The limb may be dressed upon a fenestrated wire or gauze splint, which is easier when frequent change of dressing can be foreseen, or it may be immobilized in a plaster-of-Paris splint.
The Ankle.
—The ankle is usually reached by an incision on either side, three or four inches in length, extending from above each malleolus downward and forward on to the tarsus. The knife-blade should be forced to the bone, so as to divide the periosteum, which is subsequently separated and lifted by an elevator, in order that the operation may be made subperiosteally. The fibula is usually first divided, with a chain saw or a chisel, an inch above its tip. The divided fragment is wrenched from its place with forceps, and severed from the ligaments by knife or scissors, being careful not to injure the external lateral ligament. The inner incision is made in practically the same way, the periosteum separated, the internal lateral ligament divided, and the end of the tibia forced through the incision by everting the foot. Its joint end may be removed with a saw, dividing on the same level and plane with the lower end of the fibula. Through the gap thus made the astragalus may be either removed or its upper surface divided with a metacarpal saw. The fresh bone surfaces left in this way will unite and ankylosis will result, unless fibrous or muscular tissue be interposed to favor the formation of a false joint.
As in other operations methods may be varied to meet the exigencies of certain cases. Longitudinal incisions may be placed farther forward than indicated above, as is shown in [Fig. 221], which illustrated König’s method. Here the bone surfaces are divided with broad chisels. A transverse incision of the front and upper part of the ankle may be made, through which the tendons are exposed, lifted in a group out of harm’s way, and curetting and bone sawing performed. Kocher makes a semilunar incision from the outer border of the tendo Achillis to the outer border of the extensor tendons, its line passing beneath the external malleolus. By this method the joint is opened and the peroneal tendons divided, their ends being reunited after the completion of the balance of the work. This method is usually applicable in children.
Ample drainage is required in these cases, for the operation is seldom performed in the absence of septic complications. The foot should be kept in proper and right-angled position by metallic splints, or by plaster of Paris, the latter preferable, fenestra being cut in order to make access to the wound.