A broken metal handle accompanied by femoral trunk fracture, which would shorten service life of handles. Therefore, it is necessary to judge whether the notch is the main reason for handle broken. Some literatures thought that the pores of sintered porous coated anatomic (PCA) porous layer produce the notch on the handle surface and the notches lead to the handle broken being incorrect. The Apex of the pore is taken for the bottom of the notch, expanding into a crack, and it should also not grow to the base-alloy, accordingly, the above conclusion is wrong. Some reports pointed out the notch, apex of the pore, will expand into the crack, but it is not associated with the broken handle. Under the sintering temperature, the grain boundary apertures be generated on the base metal surface, the aperture is expanded into the crack, which leads to handle broken in the forced area. However, neither theoretical basis, nor a case of corroboration, can prove exist of notch. Actually, the broken handle is caused by the sintering technology. The high temperature of sintering joining results in grain boundary aperture, when encounter the largest forced area and expand into crack, it will break the handle.

INTRODUCTION: General joining techniques are at low level, which produces some potential problems in porous layer of porous coated anatomic (PCA).LIMITATIONS: The problems in general joining techniques are caused by limitations of each technique, which could not be solved using advanced measures.APPLICATION: The activated diffusion brazing technology is an effective way. Its many advanced processes can solve those potential problems.CONCLUSION: The stress-shielding problem caused by PCA porous layer can be solved by using small metal balls in the same diameter in combination with the advanced activated diffusion brazing technology. Moreover, the high performance brazing metals by activated diffusion brazing technology is harmless for humans.

OBJECTIVE: Sintering of porous coated anatomic porous layer bonding technology remains controversial because of poor understanding to its essence.ESSENCE: Sintering is a technology that the bonding temperature exceeds 5 ℃ or higher than the base-alloy solids temperature of 1 230 ℃, resulting in base-alloy produce a series of serious problems, such as grain boundary racks, handle broken and so on.HAZARDS: In sintering temperature, the low melting point eutectlc phase and the brittle metal compounds flow out of the grain boundary to bond the small metal balls and the handle, which greatly reduces the fatigue strength. The grain boundary cracks formed and expanded ultimately leading to handle broken.DISCUSSION: The cause of a handle broken is neither notch nor metallurgical defects but sintering process, because high sintering temperature results in grain-boundary lacunas.CONCLUSION: Sintering is not suitable for connecting the force components. High sintering temperature produces grain-boundary lacunas which can expand into cracks and ultimately result in handle broken under some condition.

Objective To quantitative evaluate the myocardial microcirculation dysfunction in patients with end-stage renal disease (ESRD),and to provide the imaging characteristic for early detection myocardial dysfunction and microcirculation damage in the ESRD patients after dialysis therapy.Methods Sixty-seven patients with ESRD and 1 9 healthy subj ects were enrolled in our study, and the ESRD patients were divided into two groups including patients with preserved systolic function (n=51,EF≥50%)and patients with impaired systolic function (n=16,EF＜50%).The LV regional myocardial perfusion parameters were analyzed including upslope, time to maximum signal intensity (TTM)and max signal intensity (Max SI).Those continuous variables were compared using one-way analysis of variance (A N OVA )in all three groups.Results Compared with the controls and the ESRD patients with preserved EF,the ESRD patients with impaired EF had a significantly lower SV and markedly increased LV mass (all P＜0.001).For the fist-pass perfusion analysis,first-pass perfusion Max SI of all segments were significantly reduced in the ESRD patients with preserved/impaired EF compared with the normal subjects (all P＜0.05).Compared with the ESRD patients with preserved EF and controls,the ESRD patients with impaired EF had lower upslope in the basal segment (P＜0.05).And the ESRD patients with preserved/impaired EF had shorter TTM in the apical segment than that in normal controls (P＜0.01).Conclusion The CMR first-pass perfusion can detect the myocardial deformation and dysfunction in ESRD patients,the Max SI may be more valuable to early detect myocardial microcirculation dysfunction.

Objective:To investigate the treatment strategy for pediatric humeral supracondylar fractures with callus formation and displacement neglected for over 1 week.Methods:A retrospective analysis was made of the clinical data of 36 children who had been treated at Department of Pediatric Orthopaedics, Medical Center, The Second Affiliated Hospital, Inner Mongolia Medical University from January 2011 to January 2021 for humeral supracondylar fractures with callus formation and displacement neglected for over 1 week. There were 22 boys and 14 girls, with an age of (6.7±2.7) years (from 2.3 to 12.8 years). All fractures were Gartland type Ⅲ. The patients were divided into 2 groups according to their treatment methods: a closed reduction and percutaneous pinning (CRPP) group of 15 patients subjected to the CRPP treatment only, and a leverage group of 21 patients subjected to CRPP assisted by the "lever technique" with posterior elbow Kirschner wire prying and pulling. The 2 groups were compared in terms of operation time, fluoroscopy frequency, quality of reduction, and recovery time for elbow range of motion; the elbow range of motion, visual analogue scale (VAS), Mayo elbow performance score (MEPS) and complications were assessed at the last follow-up.Results:The 2 groups were comparable because there was no significant difference between them in the general information before operation ( P>0.05). All patients were followed up for (26.2±16.3) months (from 6 to 96 months). All the fractures obtained acceptable reduction and clinical union 4 to 6 weeks after operation. The operation time [(28.2±6.8) min] and fluoroscopy frequency [(27.0±6.0) times] in the leverage group were significantly less than those in the CRPP group [(40.8±10.8) min and (43.3±11.4) times] ( P<0.05). The CRPP group was significantly better than the leverage group in the intraoperative Baumann angle (78.1°±1.6° versus 73.7°±4.1°), lateral capitellohumeral angle (58.3°±2.6° versus 49.6°±5.2°) and horizontal rotation rate (109.5%±3.0% versus 103.2%±4.9%) ( P<0.05). The intraoperative reduction in the CRPP group was significantly closer to the normal mean value than that in the leverage group ( P<0.05). There was no significant difference in the recovery time for elbow range of motion between the CRPP and the leverage groups ( P>0.05). At the last follow-up, the Baumann angle (75.4°±2.8°) and the lateral capitellohumeral angle (53.2°±3.6°) in the leverage group were still significantly better than those in the CRPP group (78.3°±1.5° and 57.5°±2.3°) ( P<0.05). However, there was no significant difference in the elbow range of motion, VAS, MEPS or incidence of complications between the 2 groups ( P>0.05). Conclusion:To treat humeral supracondylar fractures with callus formation and displacement neglected for over 1 week in children, CRPP assisted by the "lever technique" with posterior elbow Kirschner wire prying and pulling is an efficient and accurate method, because it can lead to more satisfactory reduction than CRPP only.