Treatment of tibial bone defects caused by infection: a retrospective comparative study of bone transport using a combined technique of unilateral external fixation over an intramedullary nail versus circular external fixation over an intramedullary nail.

BACKGROUND: The purpose of the study was to assess and compare the clinical efficacy of bone transport with either circular or unilateral external fixators over an intramedullary nail in the treatment of tibial bone defects caused by infection. METHODS: Between May 2010 and January 2019, clinical and radiographic data were collected and analyzed for patients with bone defects caused by infection. Thirteen patients underwent bone transport using a unilateral external fixator over an intramedullary nail (Group A), while 12 patients were treated with a circular external fixator over an intramedullary nail (Group B). The bone and functional outcomes of both groups were assessed and compared using the Association for the Study and Application of the Method of the Ilizarov criteria, and postoperative complications were evaluated according to the Paley classification. RESULTS: A total of 25 patients were successfully treated with bone transport using external fixators over an intramedullary nail, with a mean follow-up time of 31.63 ± 5.88 months. There were no significant statistical differences in age, gender, previous surgery per patient, duration of infection, defect size, and follow-up time between Group A and Group B (P > 0.05). However, statistically significant differences were observed in operation time (187.13 ± 21.88 min vs. 255.76 ± 36.42 min, P = 0.002), intraoperative blood loss (39.26 ± 7.33 mL vs. 53.74 ± 10.69 mL, P < 0.001), external fixation time (2.02 ± 0.31 month vs. 2.57 ± 0.38 month, P = 0.045), external fixation index (0.27 ± 0.08 month/cm vs. 0.44 ± 0.09 month/cm, P = 0.042), and bone union time (8.37 ± 2.30 month vs. 9.07 ± 3.12, P = 0.032) between Group A and Group B. The excellent and good rate of bone and functional results were higher in Group A compared to Group B (76.9% vs. 75% and 84.6% vs. 58.3%). Statistically significant differences were observed in functional results (excellent/good/fair/poor, 5/6/2/0 vs. 2/5/4/1, P = 0.013) and complication per patient (0.38 vs. 1.16, P = 0.012) between Group A and Group B. CONCLUSIONS: Bone transport using a combined technique of external fixators over an intramedullary nail proved to be an effective method in treating tibial bone defects caused by infection. In comparison to circular external fixators, bone transport utilizing a unilateral external fixator over an intramedullary nail resulted in less external fixation time, fewer complications, and better functional outcomes.

Bifocal versus trifocal bone transport for the management of tibial bone defects caused by fracture-related infection: a meta-analysis.

BACKGROUND: The purpose of this meta-analysis was to compare the efficacy and outcomes of bifocal bone transport (BFT) and trifocal bone transport (TFT) for the treatment of tibial bone defects caused by fracture-related infection (FRI). METHODS: The literature searches of Cochrane Library, Embase, Google Scholar databases, PubMed/Medline, and Web of Science for literature published up to September 20, 2022, were performed. The quality of the included studies was evaluated according to the MINORS scale. Patients were divided into the BFT group and the TFT group, depending on the site of the osteotomy. The demographic data, defect size (DS), external fixation time (EFT), external fixation index (EFI), bone and functional results, complications, and autologous bone grafting (ABG) were extracted and analyzed using the Review Manager software (version 5.3). RESULTS: Five studies included 484 patients with tibial bone defects treated by bone transport investigated in this meta-analysis, with a mean bone defect of 9.3 cm. There were statistical differences in DS (MD = - 2.38, 95% CI - 3.45 to - 1.32, P < 0.0001), EFT (MD = 103.44, 95% CI 60.11 to 146.77, P < 0.00001), and EFI (MD = 26.02, 95% CI 14.38 to 37.65, P < 0.00001) between BFT group and TFT group. There was no statistical difference in bone results (RR = 0.98, 95% CI 0.91 to 1.06, P = 0.67), functional results (RR = 0.94, 95% CI 0.82 to 1.07, P = 0.37), complications (OR = 1.57, 95% CI 0.59 to 4.14, P = 0.36), and ABG (RR = 1.2, 95% CI 0.78 to 1.84, P = 0.42) between two groups. CONCLUSIONS: TFT was a feasible and practical method in the treatment of massive tibial bone defects caused by FRI to receive shorter EFT and satisfactory bone and functional results.

Bone Defects in Tibia Managed by the Bifocal vs. Trifocal Bone Transport Technique: A Retrospective Comparative Study.

Background: The purpose of this study is to evaluate the clinical effectiveness and determine the differences, if any, between the trifocal bone transport (TFT) technique and the bifocal bone transport (BFT) technique in the reconstruction of long segmental tibial bone defects caused by infection using a monolateral rail external fixator. Methods: A total of 53 consecutive patients with long segmental tibial bone defects caused by infection and treated by monolateral rail external fixator in our department were retrospectively collected and analyzed from the period January 2013 to April 2019, including 39 males and 14 females with an average age of 38.8 ± 12.4 years (range 19-65 years). Out of these, 32 patients were treated by the BFT technique, and the remaining 21 patients were managed by the TFT technique. The demographic data, operation duration (OD), docking time (DT), external fixation time (EFT), and external fixation index (EFI) were documented and analyzed. Difficulties that occur during the treatment were classified according to Paley. The clinical outcomes were evaluated by following the Association for the Study and Application of the Method of Ilizarov (ASAMI) criteria at the last clinical visit. Results: All patients achieved an infection-free union finally, and there was no significant difference between the two groups in terms of demographic data and both ASAMI bone and functional scores (p > 0.05). The mean defect size and OD in TFT (9.4 ± 1.5 cm, 161.9 ± 8.9 min) were larger than that in BFT (7.8 ± 1.8 cm, 122.5 ± 11.2 min) (p < 0.05). The mean DT, EFT, and EFI in TFT (65.9 ± 10.8 days, 328.0 ± 57.2 days, 34.8 ± 2.1 days/cm) were all less than those in BFT (96.8 ± 22.6 days, 474.5 ± 103.2 days, 60.8 ± 1.9 days/cm) (p < 0.05). Difficulties and complications were more prevalent in the BFT group than in the TFT group (p < 0.05). Conclusion: Both the trifocal and BFT techniques achieve satisfactory clinical outcomes in the reconstruction of long segmental tibial bone defects caused by infection using a monolateral rail external fixator. The TFT technique can significantly decrease the DT, EFT, EFI, difficulties, and complications compared with the BFT technique.

Tetrafocal (three osteotomies) and pentafocal (four osteotomies) bone transport using Ilizarov technique in the treatment of distal tibial defect-preliminary outcomes of 12 cases and a description of the surgical technique.

OBJECTIVE: To evaluate the preliminary outcomes of tetrafocal (three osteotomies) and pentafocal (four osteotomies) bone transport using Ilizarov technique for the treatment of distal tibial defect and describe the surgical technique. METHODS: A total of 12 eligible patients with distal tibial defect > 6 cm caused by direct trauma or posttraumatic osteomyelitis who were admitted to our institution from January 2017 to January 2019 were treated by tetrafocal or pentafocal bone transport using Ilizarov technique. Detailed demographic data, including age, sex, etiology, defect size, number of osteotomies (three or four), external fixation time (EFT) and external fixation index (EFI), were collected, and the bone and functional outcomes were evaluated by the Association for the Study and Application of the Method of Ilizarov (ASAMI) scoring system. Complications during the surgery and the follow-up period were recorded and evaluated by the Paley classification at a minimum follow-up of two years after removal of the fixator. RESULTS: There were 9 men and 3 women with an average age of 37.4±7.8 years. The etiology included posttraumatic osteomyelitis in 8 cases and posttraumatic bone loss in 4 cases. The mean bone defect after radical debridement was 7.1±0.6 cm. Tetrafocal bone transport was applied in 9 cases, and pentafocal bone transport was applied in 3 cases. The average EFT and EFI were 5.2±0.8 months and 0.7±0.2 months/cm, respectively. The average time of follow-up after removal of the external fixator was 28.5±3.3 months without recurrence of osteomyelitis. The bone results were good in 7 cases, fair in 4 cases, and poor in 1 case, and the functional results were good in 5 cases, fair in 6 cases, and poor in 1 case. The most common complication was pin tract infection, which occurred in all cases, but there were no major complications, such as nerve or vascular injury. CONCLUSION: Tetrafocal and pentafocal bone transport using Ilizarov technique could be an alternative treatment option in selected cases with distal tibial defect > 6 cm. It could shorten the distraction period, fasten regeneration, and reduce the associated complications.

NRSN2 promotes osteosarcoma cell proliferation and growth through PI3K/Akt/MTOR and Wnt/ß-catenin signaling.

Osteosarcoma is the most common bone cancer in children and adults. However, its pathogenesis, especially molecular mechanisms remain elusive. In current study, we screened GEO Database and found a poorly studied protein Neurensin-2 (NRSN2), which is highly expressed in osteosarcoma tissues. Neurensin-2 (NRSN2) is a small neuronal membrane protein and localized in small vesicles in neural cells, previous study found that it has been implicated in hepatocellular carcinoma (HCC) and non-small cell lung cancer (NSCLC). We here report that the expression of NRSN2 is more commonlyelevated in 18 fresh osteosarcoma tissues. Furthermore, both loss- and gain-functions assays revealed that NRSN2 could promote osteosarcoma cell proliferation and growth both in vitro and in vivo. In addition, we further found that those effects on osteosarcoma by NRSN2 are associated with the dysregulated PI3K/AKT/mTOR signaling and Wnt/ß-catenin signaling. In conclusion, our study found a novel oncogenic protein, NRSN2, which promotes osteosarcoma cell proliferation and as a membrane protein, NRSN2 also could be a potential treatment target for osteosarcoma.