Many protocols have been established to treat the sequelae of severe lower extremity trauma. These include early aggressive and repeated débridement of necrotic tissue, soft-tissue coverage with local muscle flaps or free muscle transfers1-3, and staged skeletal reconstruction4-8 of bone defects.
The reconstructive strategies for failed midfoot amputations are less clearly defined. We performed a staged reconstruction, combining the Ilizarov bone-lengthening technique with a latissimus dorsi free muscle transfer. The fundamental goals of the treatment were to improve the patient's quality of life as well as to provide a functional and durable reconstruction of the musculoskeletal defect. The patient was informed that data concerning the case would be submitted for publication, and she consented.
The right forefoot of a sixteen-year-old girl was run over by a train. Wound débridement and amputation of the foot at the base of the metatarsals was performed, and a split-thickness skin graft was applied. Subsequently, the patient could walk on crutches but chronic breakdown of the skin graft developed and she had persistent pain. At the age of eighteen years, when first seen by us, she had an amputation at the midfoot level with unstable skin coverage (Figs. 1-A and 1-B). The surgical treatment plan we recommended was accepted by the patient.
The first of a two-stage reconstruction included débridement of the previous skin graft and coverage of the resultant defect with a free latissimus dorsi muscle transfer covered by a split-thickness skin graft. The free muscle flap was purposefully left bulky to permit later metatarsal lengthening (Figs. 2-A and 2-B).
Two months following the latissimus dorsi muscle transfer, the second stage of the reconstruction was performed, consisting of lengthening of the midfoot with use of the Ilizarov method. With use of a thin-bladed osteotome, corticotomies were made in the remaining cuneiforms and bases of the metatarsals. Consecutively, wires were placed distal and proximal to the corticotomies. The wires were attached to two full Ilizarov rings and tensioned in the usual manner. Seven days following application of the Ilizarov device, distraction was started at the rate of 0.25 mm, four times per day. Distraction was continued for fourteen weeks until the regenerated metatarsals reached the length of the contralateral metatarsals for a total lengthening of 3.25 cm (Fig. 3).
The Ilizarov frame was removed six months after application, at which time radiographs demonstrated corticalization of the regenerated bone (Fig. 4).
Over the ensuing four years, the patient underwent debulking and tailoring of the free latissimus flap on two separate occasions in order to facilitate normal shoe wear.
At the ten-year follow-up, the patient had a stable, pain-free foot with functional hind foot and ankle motion, as well as a nearly normal gait (Figs. 5-A and 5-B). She was gainfully employed as a secretary, and there had been no further episodes of skin-graft breakdown nor need for further contouring of the latissimus dorsi flap.
The case of this patient illustrates the application of two distinct technological advances used together to provide an injured patient with a functional foot capable of normal shoe wear. In the staged treatment, the transferred muscle flap was intentionally left bulky to accommodate the later osseous transport.
One could argue that resurfacing of the unstable soft tissue alone would have been sufficient to allow the patient to walk when combined with a forefoot prosthetic component. A reconstructive approach that required a total of five operations, four hospitalizations, and four years to obtain the final outcome can be questioned. Yet for this young, active woman, the functional and psychosocial gains were substantial, enabling her to function with a pain-free gait and wear normal shoes, with the exception of high-heeled shoes. There have been several reports on the successful transfer of a vascularized skin flap from the groin to resurface a soft-tissue defect of the distal aspect of the lower extremity. The free transfer of the latissimus dorsi muscle, with use of the microvascular technique, has a similar rationale9-13, but with several advantages over transfers from the groin. The latissimus dorsi muscle transfer has a consistently large and long vascular pedicle, allowing for a technically easy anastomosis to recipient vessels. The transfer can be designed to vary greatly in size and, when necessary, can cover much larger defects than the island groin flap, allowing the surgeon to be more aggressive not only with the débridement of the infected bone and soft tissue but also with subsequent reconstructive procedures. Finally, transfer of the latissimus dorsi muscle results in little functional or aesthetic morbidity of the donor site14,15.
There have been few reports of the lengthening of short stumps following traumatic amputations16-19. The past success of bone-lengthening with use of the Ilizarov device provides an opportunity to explore the lengthening of short amputation stumps to improve function. The advantages of the Ilizarov fixator include minimal surgical trauma and bleeding, early weight-bearing, progressive deformity correction during the treatment, and restoration of large bone defects20. The Ilizarov method is limited less than other methods by the magnitude of the deformity21.
Our review of the literature revealed no reports of multiple metatarsal lengthenings after a traumatic transmetatarsal amputation. When "metatarsal amputation" was used as a search term, all reports were related to metatarsal lengthening in congenital foot deformities.
While acute lengthening for correction of brachymetatarsia with an autogenous bone graft was first described by McGlamry and Cooper22, some authors prefer gradual lengthening with external fixation when >1 cm of lengthening is the goal23.
The benefits of gradual metatarsal lengthening include adjusting the rate of lengthening, allowing the patient to bear weight during treatment, and providing the patient with the opportunity of having input with respect to the final length24. Compared with acute lengthening, the risks of soft-tissue stretching are lower23.
Dedmond and Davids25 defined skin-graft dysfunction in children following lower extremity amputation as breakdown, contracture, and/or pain, complications considered to be clinically relevant if they required the child to discontinue use of the prosthesis for any period of time or if they required revision surgery to facilitate continued prosthetic fitting. They thought that partial-thickness skin-grafting (involving =25% of the surface area) was an effective option for children with an acquired lower-extremity amputation defect.
Dedmond and Davids also concluded that limited skin-grafting (involving 26% to 50% of the surface area) is more likely to result in skin-graft breakdown, particularly when the graft is located distally. They reported that extensive skin grafts, while technically possible, frequently require revision, which rarely results in an optimally functioning limb. Thus, alternative treatment strategies should be considered for amputation stumps that require extensive distal skin-grafting.
Matsen et al.26 concluded that the perceived result of amputation is not associated with the amount of limb amputated, but rather with factors that may be optimized by surgical, prosthetic, and social management strategies, such as increasing experience with the prosthetic device and continued modification of its fit. In this context, the proposed treatment method can provide a functional long-term solution for the short foot amputation with recurrent skin breakdown. Our technique combined three critical factors: free-flap soft-tissue cover, distraction bone-lengthening, and patient and family compliance. The combination of these factors was the key to long-term success for this patient. The cost of the treatment reported for our patient was substantial, as it involved five operations and four hospitalizations. Given the economic considerations, this approach is not feasible for all patients with transmetatarsal amputations and skin-graft problems who may be managed by more conservative treatment. However, in selected patients, this may be an effective option.