How are transtibial lower-extremity amputations performed?

Updated: Apr 29, 2021
  • Author: Janos P Ertl, MD; Chief Editor: Vinod K Panchbhavi, MD, FACS, FAOA, FABOS, FAAOS  more...
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Informed consent is obtained from all patients. In patients in whom a very short residual limb is expected, the possibility of knee disarticulation or amputation above the knee is also discussed. Every attempt is made to maintain the knee joint. The patient is positioned supine. A bump under the hip may be used to control rotation of the limb, and a tourniquet is applied. In patients with vascular disease, tourniquet use is on a discretionary basis. After preparing and draping of the extremity, previous incisions are used, if appropriate. No differences in wound healing between anterior-posterior, oblique, and medial-lateral incisions have been reported.

After incision, dissection is carried down to the muscular layer, then carried more proximally, with the anterior, lateral, and posterior compartments identified and isolated. If a long posterior muscle flap was used for anterior coverage in the primary amputation, care should be taken to preserve the length of this posterior muscle compartment. During isolation of the muscle compartments, care should also be taken to maintain the fascial attachments to the musculature for later myoplastic reconstruction.

After isolation of the muscle compartments, the main neurovascular structures are identified, released from scar tissue, and separated. This should include the tibial nerve, artery, and vein; the superficial and deep peroneal nerves and the peroneal artery and vein; the sural nerve; and the saphenous nerve and vein. The identified nerve should be transected as high as possible and allowed to retract into the soft-tissue bed. The artery and nerve are separated and ligated in a separate fashion.

Once soft-tissue dissection is completed, attention is turned to the osseous structures. The periosteum is incised from anterior to posterior on the fibula and tibia. With a 45° chisel, an osteoperiosteal flap is elevated medially and laterally in such a way as to maintain the proximal attachment. Small cortical fragments are left attached to the periosteum.

Once the osteoperiosteal flaps are created, any exposed cortical bone that remains is resected to the same level, thereby facilitating the suturing of the osteoperiosteal flaps. This requires no more than 1.5-2 cm of bone to be resected. The medial tibial flap is sutured to the lateral fibular flap, and the lateral tibial flap is sutured to the medial fibular flap, resulting in a tubelike structure.

In short or very short residual extremities, free osteoperiosteal grafts are harvested from the proximal tibia, contralateral extremity, or iliac crest to maintain bony length. This may also be performed on any length of residual extremity. The authors have used free osteoperiosteal grafts harvested from the removed limb in primary amputations without difficulty and with complete synostosis formation.

Some short transtibial extremities exhibit abduction of the fibula (abducted fibula) secondary to the pull of the biceps femoris. This may lead to a lateral pressure point and prosthetic difficulties. The fibula is reduced into an adducted position and a lag screw placed into the proximal tibiofibular joint, stabilizing this dynamic deformity with or without an arthrodesis of this joint.

The mobilized musculature is then brought distally, covering the osteoperiosteal bridge, and a myoplasty is completed, suturing the posterior musculature to the anterior and lateral musculature. (If there is a length discrepancy, then a myodesis can be performed.) However, the goal is to provide soft-tissue coverage for the distal aspect of the residual extremity.

The Ertl technique, an osteomyoplastic transtibial amputation procedure that involves forming a tibiofibular bone bridge to provide a stable tibiofibular articulation that may be capable of some distal weightbearing, may be used to create a highly functional residual limb. [33] Further study is needed to define patient selection, technical details, and postoperative care for this technique.

After the completion of the myoplasty, the skin is mobilized over the underlying myoplasty. Care is taken to reapproximate the skin in a symmetric fashion, leaving neither "dog ears" nor crevices. Drains are placed to prevent hematoma formation. After sterile dressings are applied, the extremity is placed in a plaster splint in extension. The splint is removed after 2-7 days.

The use of a temporary total-contact end-bearing prosthesis is begun after 5-8 weeks. Physical therapy is also instituted for patient education on transfers, desensitization of the residual extremity, aerobic conditioning, and upper-body strengthening.

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