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BACKGROUND: The pathogenesis of osteonecrosis of the femoral head (ONFH) still needs to be further studied, so it is necessary to establish an animal model that can highly simulate ONFH in humans. However, how to correctly evaluate the animal model of ONFH is a prerequisite for establishing the animal model of ONFH. OBJECTIVE: To summarize the evaluation methods of ONFH animal models worldwide in recent years, review the advantages and disadvantages of each evaluation method, explore new evaluation methods, and provide reference for the establishment of animal models. METHODS: Literatures related to the evaluation methods of ONFH animal models published from January 2010 to September 2020 were retrieved in CNKI, WanFang, VIP, PubMed, Web of Science and Medline with the terms “osteonecrosis of femoral head, femoral head necrosis, animal model, evaluation methods” as the retrieval words. RESULTS AND CONCLUSION: A total of 51 articles were included according to the inclusion criteria, including 33 in Chinese and 18 in English. In recent years, with the development of imaging technology and the introduction of new technologies, the evaluation options of ONFH animal model increase. Choosing a reasonable evaluation method can reduce the workload in the process of establishing animal models and provide reference for the follow-up research. So, the further improvement is necessary. [ABSTRACT FROM AUTHOR]

BACKGROUND: The development of a model of femoral head necrosis has been slow, and most studies have not elaborated the advantages and disadvantages of various animal models and optimal selection methods OBJECTIVE: To explore the most suitable animal modeling methods and modeling ideas, summarize the advantages and disadvantages of each model, and point out the existing problems and solutions, providing basis and ideas for the subsequent research on femoral head necrosis. METHODS: A search of CNKI, PubMed, and WanFang databases was performed for relevant articles published from 2009 to 2020 using the keywords of “osteonecrosis of the femoral head, animal model, osteoarthritis, collapse of the femoral head, trauma, corticosteroid, alcohol, liquid nitrogen” in Chinese and English, respectively. Finally, 55 eligible articles were included for review. RESULTS AND CONCLUSION: Common causes of femoral head necrosis include alcohol, hormones, and mechanical trauma. Among them, there is no vomiting reflex center in rats, which is more commonly used in alcohol-based modeling. The mechanism of hormone-induced osteonecrosis of the femoral head is still unclear, mainly including three hypotheses: fat metabolism disorder, intravascular coagulation and osteoporosis. The pathogenesis of hormone-induced modeling in animal experiments is similar to humans, and it can also reflect the pathological changes of femoral head necrosis in the advanced stage. After the trauma, the femoral head suffers subchondral fracture and local collapse caused blood circulation disorder, which causes ischemic necrosis of the femoral head. But in animal experiments, the pathogenesis of trauma in animals is different from that of humans. However, there are certain problems in various animal studies: (1) In the modeling of hormone-induced models, there is no unified standard for the selection and dosage of hormones, and the uncertainty of the site of model necrosis. (2) The freezing dog model is more popular in recent years, but it lacks mature and accurate operation methods. The uncertainty of the freezing range has a certain impact on the later stage of modeling. (3) The pathogenesis in most trauma models is different from human pathogenesis. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Cervical pedicle screw fixation is a reliable method for the treatment of traumatic and non-traumatic cervical instability and cervical disc removal and fixation; however, the operation risks and the failure rate of screw insertion are still high. At present, the digital navigation template with digital computer technology, used in the department of orthopedics, has the advantages of accurate screw insertion and a small error in the screw insertion depth. OBJECTIVE: To observe the clinical efficacy and safety of the digital navigation template combined with cervical pedicle screw implantation. METHODS: This is a prospective, single-center, self-controlled, clinical trial. Thirty-two patients with cervical spondylosis will be recruited from the Harrison International Peace Hospital, Hebei Province, China. Before surgery, a three-dimensional (3D) navigation model of the cervical vertebrae will be designed by 3D reconstruction. The navigation template will be generated by 3D printing. The cervical pedicle screws will be implanted according to preoperatively designed models and the screw positions will be observed by computerized tomography (CT) after surgery. The patients will be followed up for 40 months. The primary outcome measure is the excellent and good rate of screw position 40 months after implantation. The secondary outcome measures include the Visual Analog Scale score, American Spinal Injury Association classification, cervical X-ray and CT images before implantation and 40 months after implantation, and the incidence of adverse reactions 40 months after implantation. The protocols have been approved by the Ethics Committee of the Harrison International Peace Hospital in China (approval number: 20120630). The study protocol has been conducted in accordance with the Declaration of Helsinki, formulated by the World Medical Association. Written informed consent will be obtained from all participants. The recruitment of subjects will begin in December 2017. Samples and data will be collected from December 2017 to April 2019. Outcome measures will be analyzed in October 2020. This trial will be completed in November 2020. The results of the trial will be reported in a scientific conference or disseminated in a peer-reviewed journal. This trial has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-ONC-17013481). DISCUSSION: We will verify a high success rate of cervical pedicle screw implantation using the digital navigation template. The operation is simple and quick, with good efficacy and safety. [ABSTRACT FROM AUTHOR]