FIG. 4. Same case as Fig 3, knee drawn by rubber bands into extended position. Whereas in the preceding figure the knee was flexed by muscular action, no muscular contraction is being exerted here to hold the lower leg in full extension, this being accomplished by the traction of the rubber bands. Observe that the effect of the thrust from the eccentric fulcrum can be seen in the tightening of the upper end of the cast about the tissues of the thigh. The thrust on the foot has had to be relieved by the excision of a ring from the plaster cast just below the malleoli. Painless voluntary motion is possible through the arc representing the difference between the position in this figure and that in Fig. 3. preferably with a saw, naturally taking off all the tension before doing so. When the tension is reapplied the two cut surfaces will be forced together, and the "cast" will have been shortened by just the width of the ring that was removed. The force of the artificial muscle will now be employed more in straightening and less in distraction. A firm band of adhesive plaster, 2 in. to 3 in. wide, around the cut will practically maintain even apposition of the cut edges of the "plaster cast." After a day or two it may be necessary to alter again the play of the apparatus by removing another half-inch ring at the ankle, and, perhaps, one such ring from over the middle of the thigh. As long as no pain is felt in the knee, the surgeon may feel pretty safe in removing, if necessary, several half-inch rings from the ankle and from the thigh, but in cases of "healed" septic and tubercular arthritis, it is prudent to maintain some thrust against the foot and against the pelvis throughout the whole period of straightening, and indeed, for some days after full extension has been attained. As soon as the surgeon comes to feel perfectly certain that no untoward reaction is going to develop in the joint, he may add to his patient's comfort by cutting away entirely that part of the "cast" which surrounds the foot, and by shortening the upper end of the "cast' so that it shall no longer impinge against the pelvis, and the patient may, for some weeks, continue to wear the shortened apparatus for the purpose of maintaining the correction. In "rheumatic" cases, where the element of distraction is not thought to be necessary, the process of straightening can be carried through almost entirely without pain, or even discomfort. There is one very great advantage which the rubber bands develop over the wooden wedges. When the latter are used the limb may indeed be straightened, but the ready mobility of the limb is not immediately restored throughout the newly gained arc of motion, and the deformity, moreover, is very prone to relapse when the apparatus is removed. When, on the other hand, rubber traction bands are used, the hamstring muscles, though constantly subjected to a traction that we may make as heavy as we choose, remain always free to contract volun tarily to the point of the flexion deformity originally present when the "cast" was applied. In fact, the promptest manner in which the patient can obtain relief from the pressure at either extremity of the "cast," is by flexing the knee voluntarily against the traction exerted by the artificial extensor. Just as soon as the voluntary contraction of the hamstrings ceases, the artificial quadriceps extensor comes at once into play to extend the knee again to the full extent that the state of the contracture will permit, and the constant play and exercise of the knee through the alternating voluntary contraction and relaxation of the hamstrings has three great advantages over the steady and unrelaxed extension by wedging; first, it gives assurance of the prompt restoration of mobility throughout the newly acquired arc of motion of the knee, and prepares the long-unused portions of the articular surfaces of the joint for weight-bearing; secondly, it promotes much better nutritional conditions in the contractured hamstring muscles than when by the fixed wedging they are subjected to unrelaxed extension, and thus favors a restitutio ad integrum in the sclerotic muscle fibres; thirdly, it appears at least probable that the tendency to the recurrence of the deformity will, by this last factor, be lessened so that the apparatus can therefore be discarded more promptly when the hinged splint is actuated by elastic rubber bands than when the same apparatus is actuated by unyielding wooden wedges. This somewhat detailed consideration of the application of the hinged splint to the correction of flexion-ankylosis of the knee will have brought out the general principles of the apparatus, and has shown that, thanks to the eccentricity of the fulcrum, which is situated in advance of the apex of the angular deformity, the opening of that angle to 180 degrees, which is the primary object aimed at, entails, as a corollary, a very marked thrust away from the knee, both upward, toward the pelvis, and downward, toward the foot. DISCUSSION. DR. ANSEL G. Cook (Hartford): I feel certain that none of you who are not orthopedic surgeons have any idea of the value of the paper to which you have just listened. Many men have studied hard and done good work, and have a deserved reputation for skill, and yet they have added nothing to the sum total of human knowledge. The application of these principles to orthopedic practice is absolutely new. The fact that traction in the line of the body makes intra-articular pressure has long been known. We have sought to avoid this by making traction in the line of the deformity, and for this purpose we have repeatedly made all sorts of rests for the femur to lie on. Nothing like the principle of the eccentric fulcrum has ever been applied before. It is the application of a well-known mechanical principle to a new use. This paper is not only new but it is valuable. It is new because the principle has never been used before. It is so simple that if one once sees it applied he wonders why he himself has not thought of it before. Dr. Bacon has now told us of it, and shows us how to do something that we were unable to do before, but have wanted to do, in an efficient way. The use of the rubber bands is not new and not original, and if Dr. Bacon will pardon me, I don't think they are desirable. You know that no orthopedic surgeon will use the device of any other one unless he is forced to. If Dr. Bacon objects to this, I have only to remind him that it was this same attitude of mind that made him devise this very valuable splint. We have used so many of these rubber bands in the treatment of club foot and with the Thomas Splints that we have come to believe that a steady pull is better. When I go home and have a chance to use this new method, I shall use a strap and a buckle instead of the rubber bands. |