[Research on Self-tapping Performance Test of Self-tapping Bone Screws].

OBJECTIVE: To study the self-tapping performance test method of self-tapping bone screws based on the YY/T 1505 standard. METHODS: With reference to the method of YY/T 1505, various factors affecting the self-tapping force test was optimised, and the self-tapping force judgment method was improved. RESULTS: The experimental results showed that the self-tapping force obtained by the improved self-tapping force judgment method has good repeatability and high stability of the experimental data. At the same time, the test results of other influencing factors indicated that the manufacturer should fully consider the test material and the size of the pre-drilled hole. CONCLUSIONS: An improved method for judging the self-tapping force is helpful for the repeatability and stability of the test data. This study has certain significance referring to the self-tapping performance test of self-tapping bone screws.

[Study on the Fixation Effect of Plate in the Middle Tibial Fracture Based on Finite Element Analysis].

In this study, tibial shaft fracture has been treated with implants as numerically to investigate the stress behavior and the effect of plate material, position and length under pressure load. Plates of stainless steel, titanium alloy(Ti6Al4V), or CF-PEEK(CF50) were used to fix the tibial shaft comminuted fracture in different location and different working length. The maximum stress, the maximum micromotion of fracture and the stress shielding of cortex bone were analyzed. CF50 is more ideal biomechanical fixation material than traditional metal material for the treatment of tibial shaft comminuted fractures. In the treatment of tibial shaft comminuted fracture, lateral position and with relatively long working length of the plate have the advantages in micromotion, stress and stress shielding rate of the fracture end.

[New Design of Revivent TC System].

Left ventricular aneurysm (LVA) is a common complication of myocardial infarction. Traditional medical and surgical treatments are not effective or require high doctors' operational skills and patients' physical fitness. With the development of minimally invasive medical devices, it becomes possible for revivent TC system to treat LVA and reconstruct the left ventricle. This study introduces an existing product and its defect when used. From the perspective of clinical needs, we propose a new design of revivent TC system which realizes accurate force measurement and simplifies surgery.

[Finite Element Analysis of Biodegradable Polylactic Acid Stent].

Biodegradable vascular stent, also known as the third generation stent, has recently been widely studied. Finite element models of three stents with the same structure and different specifications were developed. The mechanical behavior under crimping, expanding and fatigue testing were assessed by von Mises yield and Goodman convergence. The maximum stress during crimping, expanding and fatigue testing were all observed in the stent with the largest size. The results indicated that the largest stent had the highest risk of failure and also provided theoretical evidence for the worst case scenario in the fatigue testing.

[Study on the Testing of Anti-deforming Capability of Sterile Vagina Dilator for Single Use].

The single-use sterile vagina dilator is the common medical device mainly used for gynecological examination, and the anti-deforming capability is the key property assuring safety and efficiency. The influence factors of deformation capacity are studied and analyzed according to the testing method described in the standard YY 0336-2013.

[A Drug Delivery Device for Drug-eluting Stents Simulating the Cardiovascular Blood Flow Pattern].

A novel drug delivery device simulating the cardiovascular bloodfl ow pattern was introduced. The device was used to simulate the in vivo drug release in the drug-eluting stents. The results regarding the drug release rate were subject to the pattern from in vivo measurement. Therefore, the device was validated as a measurement method for in vivo drug release rate.

Outcomes of endovascular treatment for patients with TASC II D femoropopliteal occlusive disease: a single center study.

BACKGROUND: Advances in endovascular technology led to an alternative treatment option for TASC II D (TransAtlantic Inter-Society Consensus II class D) lesions. This study was aimed to evaluate the outcomes of endovascular treatment for TASC II D femoropopliteal lesions. METHODS: Endovascular intervention with bare nitinol stent implantation was performed on 58 limbs (53 patients) with TASC II D femoropopliteal lesions from January 2011 to March 2013. Kaplan-Meier curves of primary patency, assisted patency and second patency were performed. Predictive factors of re-stenosis/occlusion were evaluated by univariate methods. RESULTS: Total 53 patients with mean age of 74.2 ± 8.2 (range, 58.0-91.0 years) and mean lesion length of 314.8 ± 64.3 mm (188.2-400.4 mm) were enrolled. The mean follow-up time was 12.2 ± 6.1 months (5-38 months). Revascularization was successfully on 95% lesions by bare nitinol stent implantation. Primary patency rates at 1, 2 and 3 years were 63%, 12% and 12%, respectively. Assisted primary patency rates at 1, 2 and 3 years were 77%, 31% and 31%, respectively. Secondary patency rates at 1, 2 and 3 years were 96%, 63% and 63%. During one-year follow-up, no major amputation was occurred. Univariate analysis revealed that number of run-off vessels was a potential predictor of re-stenosis/occlusion. CONCLUSION: Endovascular treatment of TASC II D femoropopliteal artery occlusion has a high technical success rate with acceptable one-year patency rate. The long-term outcomes are poor, but endovascular intervention could be a good alternative for patients unsuitable for surgical bypass.

[Analysis the cupric ion release characteristics of different copper raw materials in intrauterine device in vitro using ICP method].

OBJECTIVE: To study the Cupric ion release characteristics of different copper raw materials in intrauterine device in vitro by ICP. Reveal the relationship between purity and shape of Cu-IUD copper and copper ion release. METHODS: According to a certain proportion, the copper raw materials were 100 times diluted into the simulated uterine solution at 37 +/- 0.5 degrees C. Replaced medium at certain time points and collected soaking liquid. Using ICP analyzed the concentration of copper ion released. RESULTS: The largest daily release of copper ions was in the first 7 days. There was no statistically significant difference between the copper ion release amount of 99.99% and 99.95% purity copper wire (P > 0.05). The release of copper ion of the copper wire was far greater than that of the copper pipe in early stage (P < 0.01). The release amount decreased and stabilized at 56 day. CONCLUSION: Release characteristics of copper ion could effectively analysis by ICP. And in the same area, the release amount of copper ions of copper wire was greater than that of copper pipe.

[Study on the release of copper ion and corrosion for intrauterine contraceptive device with two kinds of Cu-containing stent].

Two kinds of Cu-containing intrauterine contraceptive device (Cu-IUD) has been evaluated through the study on the release of copper ion and corrosion of copper surface in artificially formulated fluid. The result showed that the copper ions were released profusely from the stainless steel stents Cu-IUD in the first week of soak (25-12 microg/d), and then it became slowly and steady. The release of the copper ions from the titanium nickel shape memory alloy stents Cu-IUD were always slowly and steady in two months (0.5-5 microg/d). It obviously shows that the corrosion on copper surface of stainless steel stents Cu-IUD were more serious than titanium nickel shape memory alloy stents Cu-IUD by using 200 times microscope testing before and after soaking in formulated fluid.

[Optimization based on finite element technique of nitinol stent].

The finite element method was used for simulating the mechanical performance and fatigue safety of three different structures of Nitinol stent. According to the actual situation, after proposing reasonable assumptions and simplification, the geometry model and finite element model establishment, material mode selection and boundary condition setting are completed. The strain and fatigue life of different stent edges wide (omega) or strut angle (theta) are computed. The result can provide a valuable reference for the optimal design of stent.

[Research and analysis of failure data of contemporary artificial joint registration system].

This paper is aimed to focus on the joint prosthesis failure event, to collect the statistic data about the failure of artificial joints issued by authoritative organizations at home and aboard, and to compare the functions of different types of the artificial joints. We generalized and compared current study analyzing the failure reason and type of joint prosthesis, and categorized the failure events according to the failure occurring time, i. e. short-term, medium-term and long-term. This paper could be helpful for improving and summarizing of artificial joint replacement surgery, and could put forward the requirements for the future artificial joints.

[FE modeling and analysis of the locking plate for proximal humerus fracture].

The FE model of proximal humeral locking plate was established and analyzed to provide academic support of the proximal humeral locking plate failure. The stress distributions of the locking plate were observed under the situations of the fracture area providing support and without support. In summary, this type of locking plate cannot afford the stress at 120 degrees abduction position under the situation of fracture area provides without support. In order to reduce the probability of locking plate failure, it is recommended that using other type of locking plate instead or avoiding 120 degree abduction of the patient.

[Design & development of orthopedics implants failure management system].

The orthopedics implants failure management system has been put forward according to the present status. The function of the system and typical failure case reasoning route also have been described. Furthermore, the analysis process has been presented by illustrating a typical failure case analysis.

[The artificial joint failure types and analysis].

This paper focused on the joint prosthesis failure event, through survey and investigation in different kinds of case studies, generalized and analyzed the failure reason of joint prosthesis. The failure reason been categorized according to the failure occurring time: short-term, medium-term and long-term, and for each category, the characteristics and root causes are discussed, and the corresponding countermeasures put forward.

[Failure analysis of orthopedic implants].

The clinical failure factors of Orthopedic implants which happened recent years have been summarized. The main failure factors are quality of orthopedic implants itself, iatrogenic and patient-derived. The ways to preventive measures have been suggested.