Evaluation of Intraobserver and Interobserver Reliability of Mechanical Axis Alignment Measure of the Lower Limb through the Panoramic Radiograph in Patients in the Preoperative and Postoperative Periods of Total Knee Arthroplasty

Objective: To evaluate intraobserver and interobserver reliability of the measurement of the mechanical axis of the lower limb by means of the panoramic radiograph of lower limbs by physicians with different levels of medical practice. Method: A retrospective cross-sectional study with preoperative and postoperative radiographic analysis of a group of 100 patients submitted to total knee arthroplasty. Results: It was observed that there is a highly significant intraobserver and interobserver agreement (p < 0.0001), both preoperatively and postoperatively, among four observers with different training levels. Conclusion: The panoramic radiograph of the lower limbs is a reliable method for measuring the mechanical axis of the lower limb in patients submitted to total knee arthroplasty, regardless of the level of medical practice of the evaluator.

Postoperative Mechanical Axis Alignment and Components Position after Conventional and Patient-Specific Total Knee Arthroplasty

Introduction: Accurate postoperative alignment and implant positioning are determinant factors for successful total knee arthroplasty (TKA). Patient-specific template (PST) is a technique that uses computer technology for the planning, deigning and production of cutting guides. This study aims to compare PST to conventional technique in terms of mechanical axis alignment and component positioning. Patients and method: 109 TKA were performed for 78 patients in 2 groups. Group A included 69 conventional TKA in 55 patients and Group B included 40 patient-specific TKA in 23 patient. Postoperative long-film X-rays were done for all patients to observe the mechanical axis, anatomical axis, lateral distal femoral mechanical angle and medial proximal tibial angle. Results: No statistically significant difference was found between the two groups regarding alignment or component positioning. Conclusion: Both techniques have shown similar results in restoring the mechanical axis and alignment after TKA. However, PST had the advantages of reduced blood loss and shorter operative time.

Determinations of directions of the mean stress field in Sichuan-Yunnan region from a number of focal mechanism solutions

Based on the spatial orientation and slip direction of the fault plane solutions, we present the expression of corresponding mechanical axis tensor in geographic coordinate system, and then put forward a method for calculating average mechanical axis tensor and its eigenvalues, which involves solving the corresponding eigenequation. The method for deducing mean stress field from T, B, and P axes parameters of a number of focal mechanism solutions has been verified by inverting data of mean stress fields in Fuyun region and in Tangshan region with fitting method of slip direction, and both results are consistent. To study regional average stress field, we need to choose a population of focal mechanism solutions of earthquakes in the massifs where there are significant tectonic structures. According to the focal mechanism solutions of 256 moderate-strong earthquakes occurred in 13 seismic zones of Sichuan-Yunnan region, the quantitative analysis results of stress tensor in each seismic zone have been given. The algorithm of such method is simple and convenient, which makes the method for analyzing tectonic stress field with large amount of focal mechanism solution data become quantified.

Total knee arthroplasty in Ranawat Ⅱ valgus deformity with enlarged femoral valgus cut angle:A new technique to achieve balanced gap

BACKGROUND Nearly 10%of patients undergoing primary total knee arthroplasty(TKA)have valgus deformity(VD)of the knee.For severe VD of the knee,a more lateral structural release is needed to achieve balance between medial and lateral space and neutral femorotibial mechanical axis(FTMA),which is challenging and technical.AIM To introduce a new surgical technique of resection,soft tissue release,and FTMA for Ranawat type-Ⅱ VD with a 5-year follow-up.METHODS A retrospective study was conducted on patients who underwent TKA from December 2011 to December 2014.Hip-knee-ankle(HKA),range of motion(ROM),Oxford knee score(OKS),and knee society score(KSS)were used to assess the joint activity of patients in the new theory TKA group(NT-TKA)and were compared with those of the conventional TKA group(C-TKA).RESULTS A total of 103 people(103 knees)were included in this study,including 42 patients with an average follow-up period of 83 mo in the C-TKA group and 61 patients with an average follow-up period of 76 mo in the NT-TKA group.Six patients had constrained prosthesis,one had common peroneal nerve injury,and two had joint instability in the C-TKA group,but none of these occurred in the NT-TKA group.There were significant statistical differences in constrained prosthesis usage and complications between the groups(P=0.002 and P=0.034,respectively).The KSS at 1 mo post-operation for the C-TKA and NT-TKA groups were 11.2±3.8 and 13.3±2.9,respectively,with a significant difference(P=0.007).However,the data of HKA,ROM,OKS KSS,and prosthesis survival rate were insignificant(P>0.05)in both the preoperative and follow-up periods.CONCLUSION Adopting 5°-7°valgus cut angle for VD and sacrificing 2°neutral FTMA for severe VD which cannot be completely corrected during TKA can reduce the need for soft tissue release,maintain early joint stability,reduce the use of constrained prostheses,and minimize postoperative complications.

Lower-limb valgus deformity associated with developmental hip dysplasia

Background Treating developmental dysplasia of the hip is often challenging. The difficulties include not only the hip surgery itself but also the treatment of the associated lower-limb valgus deformity. However, there have been very few studies on such deformity in patients with developmental hip dysplasia. In this study, we investigated the prevalence and severity of lower-limb valgus deformity, along with the relationship between the severity of valgus deformity and mechanical alterations of the hip or the ipsilateral knee. Methods Two hundred and six affected lower limbs of 116 adult patients with untreated developmental dysplasia of the hip were included in the study, grouped according to the severity of hip dysplasia. Each study participant＇s radiographs were measured to quantitatively evaluate the mechanical axis deviation of the lower limb, and further to evaluate the prevalence and severity of the lower-limb valgus deformity. Some mechanical alterations of the hip and the ipsilateral knee were also measured on the radiographs. Results Of the affected lower limbs, 14.1% had valgus deformities. Study participants with Crowe type III hip dysplasia had the most severe deformity and the highest prevalence of deformity. Severity of valgus deformity had a strong positive correlation with the lateral migration of the femoral head but not with the superior migration. A decreased lateral distal femoral angle contributed to the lower-limb valgus deformity, and the lateral distal femoral angle had a strong negative correlation with the severity of valgus deformity. Conclusions Hip dysplasia is commonly associated with lower-limb valgus deformity, and the severity of the lower-limb valgus deformity is mostly affected by lateral migration but not superior migration of the femoral head. The valgus deformity may originate mainly in the distal femur, in addition to the hip joint itself. These findings can be taken into account when planning to treat the patients with hip dysplasia.

Investigation of Mechanism of Premature Ovarian Failure Regulation by Kidney-tonifying Herbs and Liver-clearing Herbs in Dingjing Decoction

Objective To investigate the mechanisms through which kidney-tonifying herbs（KTHs） and liver-clearing herbs（LCHs） in Dingjing Decoction（DJD） regulate premature ovarian failure（POF）. Methods One hundred and fifty Sprague-Dawley rats were randomly divided into five groups such as control, model, KTHs, LCHs, and DJD groups. POF-related biological molecules were examined. Factor analysis was performed to investigate the regulatory networks and key biomolecules involved in mediating POF after treatment with KTHs and LCHs. Results The master regulatory factors in the reproductive endocrine network associated with KTHs intervention included four molecules in the pituitary-ovarian axis, cortisol（CORT） in the target gland of pituitary-adrenal axis, and some molecules in the hypothalamus. In contrast, the master regulatory factors associated with LCHs intervention included four molecules in the pituitary-ovarian axis and some molecules in the hypothalamus; No biomolecules in the pituitary-adrenal axis were involved in the LCH-mediated mechanisms.Gonadotropin-releasing hormone（Gn RH）, which was identified as a common biological molecule in the hypothalamus, was involved in regulating the reproductive endocrine network in association with KTHs intervention. Conclusion KTHs directly regulates biological molecules in the pituitary-adrenal axis and indirectly regulates those in the pituitary-adrenal axis through the hypothalamus, while the LCHs only exert its effects indirectly. Gn RH is the key biological molecule associated with KTHs intervention.