Treatment of lower limb osteomyelitis is still a thorny problem in orthopedics. Patients who decide to take limb salvage treatment usually require multiple surgical treatments, resulting in soft tissue and bone defects. Nowadays there are many methods for the treatment of bone defects, containing Masquelet and Ilizarov technique. Though both techniques were originally designed to treat bone defects caused by infection, they have been widely applied in the repair of bone defects caused by other diseases nowadays, such as bone defects after trauma (21–23), congenital pseudarthrosis of the tibia (24–26), and bone defects after resection of bone tumor (4, 27, 28).
In recent years, the Masquelet technique has gradually become the main method for the treatment of bone defects after lower limb infection due to its significant advantage of induced membrane (29, 30).However, for large segment of bone defect, the classic Masquelet technique cannot obtain a sufficient amount of autologous bone graft, which is also prone to complications in donor site and may not be able to meet the correction of limb length discrepancy (LLD) and limb alignment. The traditional Ilizarov technique still has its classic advantages. Patients can bear weight early after surgery. In addition, IT also has the advantages of continuous adjustment of limb alignment with external fixation and chance of one-stage operation. It is speculated that the process of distraction osteogenesis can trigger a strong vascular response, thereby accelerating the healing of osteomyelitis or distant vascular disconnection (31). Unfortunately, long-time duration of external fixator places restrictions on its use, which would bring a lot of complications. There is no doubt that if the external fixation time can be effectively reduced, it will become very attractive.
The present study here is to investigate a novel hybrid Piston technique combining induced membrane and bone transport technique for the treatment of bone defects after lower extremity infection. We tend to remove the bone cement without disturbing the induced membrane, then performing distraction osteogenesis with external fixation in the second stage. This hybrid technique generally aims to effectively reduce the duration of external fixation and complications.
Our study demonstrated that the average EFI of PT group was significantly less than IT group and the bone healing results was not negatively affected. The traditional studies on the management of infected nonunion with Ilizarov external fixator reported an average EFI of 54.9 days/cm and 54.0 days/cm (32, 33). For induced membrane, the characteristics could be described as a vascularized structure that resembles periosteum, secreting vascular inducible factors (VEGF) (34, 35) and a maturity stage between the 4th and 6th week (36). One of the advantages of Piston technique is that the blood supply of induced membrane in bone defect area and debridement area can promote the migration of the docking sites, thus speeding up the process of distraction osteogenesis.
Delayed union or nonunion of the docking site may occur when the contact area is insufficient or the docking site does not coincide. To address this problem, several feasible options are proposed to prevent this common complication and shorten the duration of the fixator. Some surgeons chose to perform partial autogenous bone grafting, and some preferred the osteotome and curette to polish the bony edges at the docking site (37, 38). Bifocal bone transport was also reported to be effective (39). However, our Piston technique provides an exceptional osteogenic microenvironment compared with Ilizarov technique, where the induced membrane could secrete osteoinductive factors and stimulate bone regeneration. In our study, PT group had none case of delayed docking site union while IT group had 3 cases with further operations of bone graft.
Removal of the entire bone segment and continuous antibiotic release with bone cement can effectively remove the dead bone and biofilm, and so will offer a better chance of eliminating infection compared with the Ilizarov technology. Though none infection recurrence occurred in presented both groups, Sami Roukoz, et al. (40) and Sarita R Shah, et al. (41) reported that antibiotic loaded bone cement could achieve a better anti-infectious effect. A narrative review (42) showed the rate of infectious recurrence in patients with infected or noninfected critical-sized tibial bone defects treated by Ilizarov methods was 4.58%. Though there was no significant difference in the operation times between two groups, a recent logistic regression analysis (43) discovered that repeated operations, post-traumatic osteomyelitis, and internal fixation at the first stage were risk factors for recurrence of infection treated with the induced membrane technique. Based on these concerns, we recommend that the repeated operations and the surgical design of internal fixation should be carefully considered, to allow patients to receive more benefits of Piston technique.
Though the Piston technique requires two-stage operation, its advantages outweigh the disadvantages. Thanks to the potential benefits of induced membrane, rich blood supply and satisfactory union of the docking site made this Piston technique gather remarkably reduced EFI, satisfactory bone healing results and better functional results. In addition, early removal of external fixator could significantly reduce the risk of complications. In PT group, the percentage and severity of pain, joint stiffness and pin tract infection were low and no complications needed further operation treatment.