Abstract
Aims
Infections of bone usually require multiple surgery and prolonged periods of treatment. One reason for problems is found in the presence of stationary phase bacteria embedded in biofilms that show increased resistance against conventional antibiotic therapy (up to 1000x MIC). Biofilms adhere to surfaces of avital material making radical debridement a prerequisite for cure. Osseous defects are common in such conditions and need to be addressed. To avoid re-infection high local antbiotic concentrations are necessary. Allograft bone may be impregnated with high loads of antibiotics using a special incubation technique. The resulting antibiotic bone compound (ABC) provides high and long lasting concentrations at the site of infection and is likely to restore bone stock simultaneously. Based on this technology we have developed a new surgical technique.
Methods
42 patients (10–67yrs) with chronic osteitis were included into a prospective study using a standardized protocol. Infection was at the humerus (1x), femur (10x), tibia (29x) or femur+tibia (2x), respectively. Treatment consisted of removal of foreign material, radical sequestrectomy and soft-tissue debridement followed by pressurized lavage. Surfaces of sclerotic bone were trimmed down to vital areas. The remaining osseous defects were filled with ABC, using an impaction technique resulting in complete dead space management. The allograft was impregnated with vancomycin, in cases with mixed pathogens combinations with tobramycin were used. Internal fixation was performed the same time whenever applicable. Sites were drained and closed immediately; rehabilitation did not differ from uninfected procedures.
Results
1 patient died shortly after surgery from cardiac failure. 41 could be followed for a minimum of 2 and a maximum of 6years (mean 3,1years). In 2 patients wound healing was unsatisfactory requiring additional coverage with a muscle flap. 2 patients showed material failure after intramedullary nailing, requiring exchange of the implant. In those cases no sign of infection was present at the time of revision. There were 3 cases with recurrence of infection, all originating from foci not detected during the index operation and becoming apparent between 3 and 12 months after surgery. Two could successfully be revised using the same technique; one refused revision and shows continuing fistulation. Radiological incorporation of allografts appeared as after conventional bone grafting, union of pseudarthroses was achieved between 2 and 6 months after (re-) stabilization. 40 patients (95,2%) were fully weight bearing, painfree and without any sign of infection at the latest follow up.
Conclusion
Using antibiotic impregnated allograft bone eradication of pathogens, grafting of defects, dead space management and insertion of osteosynthetic material may be accomplished in a one stage procedure. Since the graft gradually is replaced by healthy own bone improved long term results may be expected as well as improved conditions in the case of another revision. The new technique provides for quick rehabilitation, improved results and markedly reduced costs of treatment in cases of bone infection.
