Management of gap non-union of tibia by tibialisation of ipsilateral vascular fibula.AS Date, SB Solanki, NP Badhe, PD Sonsale, HG Pandit
Department of Orthopaedics, Seth G S Medical College & KEM Hospital, Parel, Mumbai.
Gap non-union of tibia following traumatic bone loss or infection dramatically emphasizes the limitation of conventional reconstructive techniques. With presence of significant skin loss or poorly vascularised recepient bed, complications and failure rate increase and solution often lies in amputation. Vascularised ipsilateral fibular grafting offers a viable alternative to this. This is a series of 16 cases of gap non-union of tibia treated by tibialisation of fibula at KEM Hospital, Bombay. All the cases were secondary to osteomyelitis following compound fracture of tibia-fibula or hematogenous osteomyelitis with a large sequestrum. 15 cases had good results with good hypertrophy of bone after union. One case had poor result with fracture going into delayed union with no hypertrophy. We discuss the technique, complications and results of this procedure.
Keywords: Adolescent, Adult, Child, Female, Fibula, transplantation,Follow-Up Studies, Fracture Healing, Fractures, Ununited, complications,radiography,surgery,Human, Male, Osteomyelitis, complications,radiography,Tibial Fractures, complications,radiography,surgery,Treatment Outcome,
Non-union of tibia is a fairly common problem. The causes vary from improper treatment, severe injury to infection. In this era of competition and speed the incidence of compound tibial fractures is ever increasing. High incidence of automobile and motorcycle accidents as well as increasing popularity of sports like mountaineering and hand gliding have made open tibial fractures a common injury.
Non-union of tibia is caused by compromised vascularity of tibia. This poor vascularity is due to severe injury, energy absorption and vascular disruption. The fracture pattern is a good indication of the amount of energy dissipated in the soft tissues and bone in high energy trauma caused by bending, rotational and axial loading forces, a great deal of communication is frequently present. Amount of soft tissue injury also has influence in the course of bone healing. Higher rate of non-union with compound fractures is secondary to periosteal destruction and lack of fracture haematoma in these fractures.
When gap non-union in a bone is more than half of the diameter of the bone at the level, it presents a significant challenge to traditional bone grafting techniques. Defects larger than 8 cms following traumatic loss, dynamically emphasise the limitations of conventional reconstruction techniques. Poor skin condition and vascular compromise in recipient bed often complicates the matter and the only solution in olden days was amputation.
Vascular ipsilateral fibular grafting is a good alternative to this problem. Such a vascularised graft can participate directly in the healing process rather than be a passive scaffolding for the process of creeping substitution. It is independent of surrounding vascularity of its recipient bed. This single staged free transfer offers definite advantage over traditional techniques requiring multiple surgeries.
This is a study of 16 cases of gap non-union of tibia treated by tibialisation of fibula. All non-unions were secondary to osteomyelitis, hematogenous in 9 cases and secondary to chronic osteomyelitis following compound fractures of tibia fibula in 7 cases. All compound cases were of Gustilo type 3b.
Out of these patients, 8 were less than 10 years old, one was 17 year old and 7 were more than 20 yrs. of age. There were 7 females and 9 males. Average defect in tibia was 6.12 cms. Largest defect was 7.5 cms and smallest was 3 cms. The defect was in the proximal third in 4 patients middle third in 12 patients and none in distal third. All patients had undergone multiple procedures like debridement multiple bone grafting and external fixation in cases of compound fractures and incision and drainage, sequestrectomy in cases of osteomyelitis.
No study in the form of preoperative or postoperative angiography was done to assess the status of the peroneal artery.
We used separate incisions for both tibia and fibula. After exposing tibia, both non-union ends were freshened and the gap was measured. Deep fascia over the peroneal and anterior tibial muscles was then carefully lifted so that the fibula could be mobilised on the pedicle of these muscles. Fibula was osteotamized at both ends leaving muscle cuff attached to the bone. The muscle cuff included the peroneal as well as anterior group of muscles. The length of the osteotomised fibula exceeded the tibial defect length by about 2 inches. The detached fibula was mobilised towards the defect and fixed to the posterior aspect of tibia (after shingeling the tibial surface) with either cancellous screws or intramedullary K wire. Cancellous grafts were packed at both ends of non-union site. Postoperatively above knee plaster cast (non weight bearing) was applied. Patients were followed up and they were given a patella tendon bearing cast once there was clinic radiological evidence of consolidation. After union of the graft at both the ends, patients were allowed to walk full weight bearing.
Minimum time taken for graft union was 6 weeks (in children) and maximum time taken was one and half years (in adults). Average time for the union was 4.62 months. Excellent hypertrophy was seen in 9 cases moderate in 6 and no hypertrophy in one case. Thus, good results were obtained in 15 / 16 (94%) cases. The fibula graft showed hypertrophy within one to two years.
Knee range of movement was full in all patients after the mobilisation. Minimal equinus deformity was noticed in 2 patients while tibia vara was noticed in 9 patients.
Complications included delayed union of the graft, lack of hypertrophy and slipping of fibular strut. Fracture of the grafted fibula was noticed in one patient. In the end, all patients were able to walk without crutches or any other external support.
The aim of tibialisation of fibula is to achieve synostosis of fibula to tibia in its lateral eccentric position. In the presence of large tibial defects, this leads to eccentric loading through the fibula, which is bio mechanically unsound and stands a risk of failure.
The indications for this procedure are traumatic long bone defect (more than 6 cms.), reconstruction of defect secondary to resection, established non-union with gap and failure of conventional techniques, congenital pseudarthrosis of tibia and long tubular sequestrum following chronic osteomyelitis,,,,.
Infection should be controlled and sequestrectomy should be done before considering the procedure. If fibula is fractured, sufficient time should be given for it to unite before tibialisation.
Basic Principles of Tibialisation of Fibula:
1. Large graft of ipsilateral fibula is raised on a pedicle of peroneal and anterior tibial muscles and peroneal vessels. It is aligned and fixed to the tibia along its posterior long axis providing a sound mechanical and biological basis for union.
2. It is possible to transfer more than 20 cms. Of fibular shaft as a living graft on a pedicle.
3. The vascularised graft unites at a faster rate than conventional graft and is independent of the recipient beds vascularity.
4. Periosteal circulation should be protected by harvesting the graft extra periosteally along with the surrounding muscle cuff.
5. The vascularised graft can bridge the defect from normal bone to normal bone bypassing the avascular bed.
6. Tibialisation of fibula not only achieves union but, continues its growth and hypertrophy.
The advantages of the procedure include: Single stage surgery, less dependence on recipient bed, faster union, graft hypertrophy. The doweling of the fibula into tibial gap gives better stability.
The disadvantages and limitations of the procedure include: Primary applicability in young patients, morbidity of donor site and expertise of operative skill.
From the above study, it can be seen that there are many factors influencing union as well as hypertrophy of the graft. Rate of union is much faster in younger patients. Also the hypertrophy is maximum in younger patients. Hypertrophy of the graft also depends upon consolidation of the graft. Additional bone grafting also helps in achieving faster union. Graft hypertrophy also depends on weight bearing, Earlier the weight bearing, better is the hypertrophy. Poor hypertrophy was attributed to vascular compromise (which had occurred at the time of injury). Adequate stabilisation of the fibular graft is essential in graft union. Stiffness of the ankle was secondary to fracture or osteomyelitis and definitely not secondary to the procedure per se. Even though there was a certain degree of cosmetic disfigurement in all the cases, patients preferred a salvaged leg to an artificial leg.
Functional results also depend on early mobilisation of knee and ankle, disuse osteoporosis, muscle atrophy, neurological complications and function of the foot.
Largest series reported in literature, is by PB Chacha consisting of 11 cases. He mainly considered this procedure for patients with chronic osteomyelitis secondary to compound fractures of tibia fibula. The procedure was considered as a last resort before amputation. He reported a success rate of 90% as compared to our success rate of 94%.
During this study the technique of bone transport by Ilizarov method was not fully developed. From the experience gained in this series, we feel that tibialisation of fibula is a very good salvage procedure for management of gap union tibia.
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