Clinical outcomes of bone transport using rail fixator in the treatment of femoral nonunion or bone defect caused by infection

Nomogram construction and validation of axial deviation in patients with tibial defects treated with the Ilizarov bone transport technique

INTRODUCTION

The Ilizarov bone transport technique is widely recognised as an effective method for treating large segment bone defects in clinical practice. However, axial deviation is a common complication in the treatment of tibial large segment bone defects, which can have a serious impact on the clinical efficacy of bone transport. Our study aims to construct and validate a nomogram for predicting axial deviation of tibial bone transport.

METHOD

This study retrospectively collected data from 363 patients who underwent the tibial Ilizarov technique for bone transport. Univariate and multivariate logistic regression analyses were performed to determine the independent risk factors for axial deviation, which were later used to construct a nomogram. The nomogram was evaluated using the decision curve analysis (DCA), the calibration curve, and the area under the receiver operating characteristic curve (AUC).

RESULTS

Of the 363 patients who underwent Ilizarov tibial bone transport, 31.7% (115/363) experienced axial deviation. Multivariate logistic regression analysis showed that gender, height, defect site, and external fixation index were important risk factors for axial deviation. The AUC value of the nomogram model was 0.705. The calibration curve and the decision curve analysis showed a good consistency between the actual axial deviation and the predicted probability.

CONCLUSION

The model assigns a quantitative risk score to each variable, which can be used to predict the risk of axial deviation during tibial bone transport.

PPARγ inhibition promotes osteogenic differentiation of bone marrow mesenchymal stem cells and fracture healing

This study aimed to explore the effects of peroxisome proliferator-activated receptor γ (PPARγ) inhibition on fracture healing of nonunion and the underlying mechanisms. Bone marrow mesenchymal stem cells (BMSCs) were treated with PPARγ antagonist GW9662 (5 μM, 10 μM). Alkaline phosphatase (ALP) staining and Alizarin Red S was used to assess early stage of osteogenesis and osteogenic differentiation. GW9662 (1 mg/kg/day) were administered intraperitoneally into the rats with bone fracture. Bone healing processes in the rat femur fracture model were recorded and assessed by radiographic methods on Weeks 8, 14, and 20 postoperation. Osteogenesis and angiogenesis at the fracture sites were evaluated by radiographic and histological methods on postoperative Week 20. GW9662 treatment increased ALP activity and Alp mRNA expression in rat BMSCs. Moreover, GW9662 administration increased matrix mineralization and mRNA and protein levels of Bmp2 and Runx2 in the BMSCs. In addition, GW9662 treatment improved radiographic score in the fracture rats and increased osteogenesis-related proteins, including type I collagen, osteopontin, and osteoglycin, in the bone tissues of the fracture sites. In conclusion, PPARγ inhibition promotes osteogenic differentiation of rat BMSCs, as well as improves the fracture healing of rats through Bmp2/Runx2 signaling pathway in the rat model of bone fracture.