Background We described the use of a novel Piston technique versus Ilizarov technique to compare the effectiveness and complications for the repair of bone defect after lower limb infection. Patients and methods: We retrospectively reviewed 41 patients who had been treated at our department for lower extremity bone defects following osteomyelitis. They were 38 males and 3 females with a mean age of 43.41 (range 12 to 69 years). The infected bone defects involved 36 tibias and 5 femurs. Piston technique (PT, group A) was used in 12 patients and Ilizarov technique (IT, group B) in 29 ones. The mean duration of follow-up was 28.50 months (PT) and 29.90 months (IT). The modified Application of Methods of Illizarov (ASAMI) criteria was used to evaluate the bone healing and functional recovery. Results Complete eradication of infection and union of docking sites were accomplished well in both groups. The mean external fixator index (EFI) was 42.32 days/cm in group A versus 58.85 days/cm in group B (p < 0.001). The bone outcomes were similar between group A and B (p = 0.558) [excellent (9 vs. 19), good (3 vs.10)]; group A showed better functional outcomes than group B (p < 0.05) [excellent (7 vs. 6), good (4 vs. 12), fair (0 vs. 10) and poor (1 vs. 1)]. Pain was complained most during follow-up and group A had fewer cases of pin tract infection (1 vs. 6), adjacent joint stiffness (3 vs. 8) and delayed healing of the joint (0 vs. 3). Conclusions Satisfactory bone healing can be obtained by using both PT and IT, while PT had better functional results, lower EFI and allowed early removal of the external fixation. We have found that this novel Piston technique can improve the comfort of patients, reduce the incidence of complications, and provide a rapid and convenient rehabilitation.

Background: Infectious complex tissue defects have been described as injuries with composite infectious bone defects and extensive soft tissue damage, which are still austere challenges for orthopedists all around the world. The study retrospectively evaluated the Masquelet technique combined with the tissue flap transplantation for the treatment of infectious complex tissue defects and assess key factors of success in this technique.Methods: From December 2016 to December 2019, 22 patients of infectious complex tissue defects were recruited for the study. All the cases experienced a two-stages treatment. Thorough debridement, stabilization of fracture by external fixation and implantation of a cement spacer mixed with antibiotics in the first stage. Simultaneously, suitable tissue flaps were designed and transplanted for the soft tissue defect. 6-8 weeks later, after the elimination of the infection, the cement spacer was removed carefully from the induced membrane and cancellous bone was grafted into the site of bone defect. The average duration of follow-up was 21 months.Results: Infection was eliminated after the first stage intervention without recurrence. All the transplanted tissue flaps were survived. Bone union was achieved in all patients in a period of 16-31 weeks following the second stage surgery. According to the Paley fracture healing score, 17 patients showed excellent results and 5 patients displayed good results regarding bone outcomes. When considering functional outcomes, 14 patients exhibited excellent results and 8 patients displayed good results.Conclusions: This study showed evidences that Masquelet technique combined with tissue flap transplantation was an effective method to repair the infectious complex tissue defects. We also demonstrate that a complete soft-tissue envelope plays an important role in the formation of the induced membrane which promote bone union and in the anti-infection treatment.