Compared with non-degradable materials, biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects, and have attracted extensive attention from researchers. In the treatment of bone defects, scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role, which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue. Traditional biodegradable materials include polymers, ceramics and metals, which have been used in bone defect repairing for many years. Although these materials have more or fewer shortcomings, they are still the cornerstone of our development of a new generation of degradable materials. With the rapid development of modern science and technology, in the twenty-first century, more and more kinds of new biodegradable materials emerge in endlessly, such as new intelligent micro-nano materials and cell-based products. At the same time, there are many new fabrication technologies of improving biodegradable materials, such as modular fabrication, 3D and 4D printing, interface reinforcement and nanotechnology. This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing, especially the newly emerging materials and their fabrication technology in recent years, and look forward to the future research direction, hoping to provide researchers in the field with some inspiration and reference.

Femoral neck fracture is considered a difficult fracture to treat and often gives rise to unsatisfactory treatment results. Cannulated cancellous screws (CCS) or a sliding hip screw (SHS) are the mainstream internal fixations used for osteosynthesis of femoral neck fractures. There is a need to integrate existing data through a meta-analysis to investigate the safety and effectiveness of CCS and SHS in the treatment of femoral neck fractures. According to the Cochrane Handbook for Systematic Reviews of Interventions, we screened for the relevant studies by searching Google Scholar, the Cochrane Controlled Trials Register, the Cochrane Library, Web of Science, EMBASE, and PubMed. The PICOS criteria was used to make sure the included studies fulfilled the inclusion criteria. Pooled data showed that there were no significant differences between the SHS and CCS groups for the Harris Hip Score. Significant differences were found between the SHS and CCS groups in terms of union time, postoperative complications, blood loss, operation time, incision length and length of hospital stay. Although the SHS and CCS groups showed similar functional recovery in treatment of femoral neck fracture in terms of the Harris Hip Score, the SHS group showed fewer postoperative complications and faster union time for patients with femoral neck fractures. Therefore, compared with CCS, the use of SHS may be a more effective treatment of femoral neck fractures.

Intraarticular steroid injections are widely used in joint arthritis. However, the data regarding an association between an increased risk for arthroplasty infection after an intraarticular steroid injection are still conflicting. We conducted a meta-analysis to evaluate the evidence from relevant studies that examine the relation between intraarticular steroid injections and infection rates in subsequent joint arthroplasty and to develop GRADE based recommendations for using the steroid before arthroplasty. A systematic search of all studies published through August 2014 was conducted using the MEDLINE, EMBASE, OVID, ScienceDirect and Cochrane CENTRAL databases. The relevant studies that examined the relation between intraarticular steroid injections and infection rates in subsequent joint arthroplasty were identified. Demographic characteristics, infection rates and clinical outcomes were manually extracted from all of the selected studies. The evidence quality levels and recommendations were assessed using the GRADE system. Eight studies looking at hip and knee arthroplasties were included. Meta-analysis showed that patients with steroid injection before arthroplasty had a higher deep infection rate than patients without steroid injection (OR = 2.13, 95% CI 1.02-4.45), but no significant effect on superficial infection rate (OR = 1.75, 95% CI 0.74-4.16). The overall GRADE system evidence quality was very low, which lowers our confidence in their recommendations. Intraarticular steroid injections may lead to increased deep infection rates of subsequent joint arthroplasty but not the superficial infection rates. Due to the poor quality of the evidence currently available, further studies are still required.

X-ray images of the lower limb bone are the most commonly used imaging modality for clinical studies, and segmentation of the femur and tibia in an X-ray image is helpful for many medical studies such as diagnosis, surgery and treatment. In this paper, we propose a new approach based on pure dilated residual U-Net for the segmentation of the femur and tibia bones. The proposed approach employs dilated convolution completely to increase the receptive field, in this way, we can make full use of the advantages of dilated convolution. We conducted experiments and evaluations on datasets provided by Tianjin hospital. Comparison with the classical U-net and FusionNet, our method has fewer parameters, higher accuracy, and converges more rapidly, which means the high performance of the proposed method.