The gauze sponges are removed, and all bleeding points are clamped. Only those on the proximal side are tied, while the clamps on the distal side, which are to be removed, may be left in place. A circular incision is made through the periosteum of the femur (Figure 7), and the periosteum is pushed downward only for several centimeters with a periosteum elevator (Figure 8). During this procedure, the muscle of the upper flap may be retracted upward by means of a sterile towel or bandage placed over the muscle surface. Retraction and covering of the muscle are maintained while the femur is divided with a saw at the desired level (Figure 9). The amputated part is removed from the surgical field.
The sharp margins of the bone at the site of amputation are beveled off with a rongeur or rasp (Figure 10). If a tourniquet has been used, it is now removed, and any additional bleeding points are clamped and tied. The muscle surface is washed with warm isotonic saline until the surgeon is assured that there is good hemostasis and all bone fragments are washed away. Hip flexion is avoided during the surgical procedure, because if the hip is flexed when the distal portion of the wound is sutured, there is a tendency for the soft tissue to hold the hip in flexion.
The deep investing fascia to the muscles in the anterior and posterior flaps is approximated with interrupted sutures over the end of the femur (Figure 11). After all dead space has been obliterated by the careful approximation of the muscle layers, the fascia over the muscles in the anterior and posterior flaps is approximated with interrupted absorbable sutures (Figure 11). With adequate hemostasis drainage should be unnecessary, but if serious infection existed distal to the site of amputation, it may be advisable to institute drainage. A closed-system Silastic suction catheter may be placed at the base of the flaps, and the muscles may be closed over it. If a guillotine type of amputation was carried out, the wound is left open to be closed later in a delayed manner, or the limb may be reamputated at a higher level to permit primary closure.
Any excess or irregular tissue about the skin flaps is excised, and the subcutaneous tissue is approximated with interrupted nonabsorbable sutures. The skin flaps are brought together by the two hands of the assistant, who holds the stump at a convenient level for the surgeon while the subcutaneous and skin sutures are inserted (Figures 11 and 12). The skin is closed with interrupted nonabsorbable sutures except when infection is present, and the use of forceps on the skin edges should be avoided.
The stump is covered with a nonadherent dressing and fluffs of sterile gauze and is encased in a dressing that is snug but not too tight. This dressing may have to be changed in 24 hours, since the stump may swell, resulting in pain as well as interference with the blood supply. The immediate postoperative care includes continued insulin regulation in the diabetic. To combat swelling, the foot of the bed but not the stump may be elevated. Splints may be applied at the time of surgery to maintain extension and prevent flexion contractures, but these must be removed early so that exercises can be started in a few days.
Guillotine amputations require special care. The raw surface is covered with sterile gauze. Circumferential traction is usually applied to the proximal skin soon after surgery to prevent skin edge retraction. In some cases this will be sufficient to cover the bone ends, and healing will take place; however, when the skin cannot be brought together in this way, skin grafts may have to be applied at a later date to cover persistent areas of granulation tissue.
The immediate postsurgical fitting of a prosthesis has many advantages. These include accelerated healing and less postsurgical pain, prevention of contractures, fewer psychological problems, and the return of the patient to work or home much earlier. Some prefer the immediate application of a rigid plaster dressing snugly over the sterile dressings of the below-the-knee amputation before the patient leaves the operating room. A socket is secured into its base, and an adjustable pylon can be immediately fitted for ambulation within a few days after surgery. After the sutures have been removed and wound healing has been evaluated, a new cast-socket is reapplied. The original prosthetic unit is replaced and realigned. After the second cast-socket has been worn for 10 days, a new cast can be taken for the permanent prosthesis, which may be fitted within 30 days. Early socket changes are necessitated by shrinkage that which occurs in spite of immediate fitting. A less costly technique is use of the “air leg,” an air bag allowing the surgeon to view the stump postoperatively but permitting the patient to bear weight on it. If the rigid dressing is not used, the usual time of fitting is 8 to 10 weeks for above-knee and 10 to 12 weeks for below-knee amputations. The more distal the amputation, the longer the postoperative period prior to fitting because of the accumulation of edema.
To aid shrinkage of the stump, cotton-elastic bandages wrapped around the stump are worn continuously. The bandage is removed and reapplied every 4 hours and at bedtime, and a clean bandage is used every day. The amputee or members of the family are taught to apply the bandage. If they cannot wrap the stump properly, a heavy elastic sock called a “stump shrinker” fits over the stump and applies circumferential pressure. Crutch walking requires more energy than walking with a prosthesis. The best single index of whether the patient can use a prosthesis is whether he or she walked up until the time of amputation. Important also are the presence of other serious illnesses, poor vision, condition of the other leg, degree of cooperation and alertness, as well as balance and degree of coordination. Patients who can walk with crutches can walk with prostheses.
Every amputee has phantom sensation. Phantom in the lower extremity always remains in a normal relation to other parts of the body and disappears in most instances when a prosthesis is applied. Upper extremity phantom is distorted in relation to body image. The last portion to lose sensation is the thumb and index finger. The degree of phantom pain is largely dependent upon the degree of pain before amputation, but it may occur because of radiculopathy, because of position during operation, or when a neuroma is caught in the scar or in an area vulnerable to pressure. Exercising the phantom is helpful. If the toes are painful, the patient is asked to exercise them in his mind.
A planned program of rehabilitation is very important regardless of the type and extent of the amputation, and a coordinated follow-up involving the surgeon, physical therapist, and prosthetist is necessary. When elective amputation is planned, the physical therapist can teach crutch walking and instruct the patient in proper exercise before operation.