Prevalence of Risk Factors for Adverse Spinopelvic Mobility Among Patients Undergoing Total Hip Arthroplasty

BackgroundPatients with adverse spinopelvic mobility have higher complication rates following total hip arthroplasty (THA). Risk factors include a stiff lumbar spine, standing posterior pelvic tilt ≤ ?10°, and a severe sagittal spinal deformity (pelvic incidence minus lumbar lordosis mismatch ≥20°). The purpose of this study is to define the spinopelvic risk factors and quantify the prevalence of risk factors for pathologic spinopelvic mobility.MethodsA retrospective cohort analysis from January 2014 to February 2020 was performed on a multicenter series of 9414 primary THAs by 168 surgeons, all with preoperative spinopelvic measurements in the supine, standing, and flex-seated positions. All patients were included. The prevalence of adverse spinopelvic mobility and frequency of each spinopelvic risk factor was calculated.ResultsThe cohort was 52% female, 48% male, with an average age of 65 years. Thirteen percent of patients exhibited adverse spinopelvic mobility and 17% had one or more of the 3 risk factors. Adverse mobility was found in 35% of patients with at least 1 risk factor, 47% with at least 2 risk factors, and 57% with all 3 risk factors.ConclusionForty-six percent of patients had spinopelvic pathology driven by one or more of the risk factors. Number of risk factors present and risk of adverse spinopelvic mobility were positively correlated, with 57% of patients with all 3 risk factors exhibiting adverse spinopelvic mobility. Although this study defines the prevalence of these risk factors in this highly selected cohort, it does not report incidence in a general THA population.Level of EvidencePrognostic Level IV.     

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation

BackgroundThe present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee.MethodsOne hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups.ResultsKnees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm.ConclusionFunctional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.     

A Prophylactic Tibial Stem Reduces Rates of Early Aseptic Loosening in Patients with Severe Preoperative Varus Deformity in Primary Total Knee Arthroplasty

BackgroundPatients with a preoperative varus deformity >8 degrees are at increased risk of aseptic loosening after total knee arthroplasty. This study analyzes the effect of a tibial stem on the rate of aseptic loosening in patients with a severe preoperative varus deformity.MethodsPatients with a preoperative varus deformity of >8 degrees and 2-year minimum follow-up with a stemmed tibial component (n = 67) were matched 1:2 to patients with a similar preoperative varus deformity with a standard tibial component (n = 134). Radiolucent lines were measured on the tibia at 6 weeks, 1 year, and 2 years postoperatively using the Knee Society Radiographic Evaluation System. Failure was defined as revision due to aseptic loosening of the tibial component. Outcomes were evaluated using Student’s t-tests and log-rank tests.ResultsPatients with tibial stems had greater preoperative deformity (12.9 vs 11.3 degrees, P = .004). There was no difference in postoperative alignment (1.7 vs 2.1 degrees varus, P = .25) or tibial component angle (1.8 vs 2.1 degrees varus, P = .33). Patients with stems were more likely to have more constraint (44.8% vs 1.5%, P < .001). Progression of radiolucent lines >2 mm was observed in 17.6% (23/134) vs 5.97% (4/67) of patients in the stem group (P = .03). Rates of aseptic loosening were lower in the stem group (0% vs 5.15%, P = .05).ConclusionDespite worse preoperative deformity and higher utilization of constraint, tibial stem use in patients with severe preoperative varus deformity resulted in lower rates of aseptic loosening. Prophylactic use of stems in these patients may help increase implant survival.     

Alignment in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty: The Limb Has a Leg Up on the Component

BackgroundTo assess how implant alignment affects unicompartmental knee arthroplasty (UKA) outcome, we compared tibial component alignment of well-functioning UKAs against 2 groups of failed UKAs, revised for progression of lateral compartment arthritis (“Progression”) and aseptic loosening (“Loosening”).MethodsWe identified 37 revisions for Progression and 61 revisions for Loosening from our prospective institutional database of 3351 medial fixed-bearing UKAs performed since 2000. Revision cohorts were matched on age, gender, body mass index, and postoperative range of motion with “Successful” unrevised UKAs with minimum 10-year follow-up and Knee Society Score ≥70. Tibial component coronal (TCA) and sagittal (TSA) plane alignment was measured on postoperative radiographs. Limb alignment was quantified by hip-knee-ankle (HKA) angle on long-leg radiographs. In addition to directly comparing groups, a multivariate logistic regression examined how limb and component alignments were associated with UKA revision.ResultsIn the Progression group, component alignment was similar to the matched successes (TCA 3.6° ± 3.5° varus vs 5.1° ± 3.5° varus, P = .07; TSA 8.4° ± 4.4° vs 8.8° ± 3.6°, P = .67), whereas HKA angle was significantly more valgus (0.3° ± 3.6° valgus vs 4.4° ± 2.6° varus, P < .001). Loosening group component alignment was also similar to the matched successes (TCA 6.1° ± 3.7° varus vs 5.9° ± 3.1° varus, P = .72; TSA 8.4° ± 4.6° vs 8.1° ± 3.9°, P = .68), and HKA was significantly more varus (6.1° ± 3.1° varus vs 4.0° ± 2.7° varus, P < .001). Using a multivariate logistic regression, HKA angle was the most significant factor associated with revision (P < .001).ConclusionIn this population of revised UKAs and long-term successes, limb alignment was a more important determinant of outcome than tibial component alignment.Level of EvidenceLevel III case-control study.     

桔梗叶绿体比较基因组学分析及系统发育研究

目的 以桔梗Platycodon grandiflorus为材料,分析其叶绿体基因组特征,探究不同地区桔梗叶绿体基因组的差异及桔梗科其他物种的系统发育关系。方法 利用Illumina NovaSeq测序平台对桔梗叶绿体全基因组进行测序,完成其组装、注释和特征分析,采用生物信息学方法对不同地区桔梗进行比较基因组分析和系统发育分析。结果 桔梗叶绿体基因组全长172 770 bp,呈现典型的环状四分体结构,总GC含量为38.10%,注释到139个基因,其中蛋白质编码基因95个,核糖体RNA 8个和转运RNA 36个。经序列分析鉴定出139个SSR位点,大部分重复由A和T组成。该叶绿体基因组密码子偏好性A/U大于G/C。边界分析表明,不同地区桔梗的JLA边界区域存在差异。对比不同地区桔梗叶绿体基因组序列发现21个变异区间,包括ycf1、psbC、rps18和rpoB等编码区以及rpl32-trnL、trnS-psbZ和trnN-ycf1等非编码区。基于最大似然法（maximum likelihood method,ML）对桔梗及其他17种桔梗科植物进行系统发育分析,发现桔梗科物种形成一个单系群,各属物种聚为一束,支持率达100%。结论 桔梗科物种聚为一支与传统相符合,不同地区桔梗叶绿体基因组序列存在显著差异,为后期开展分子鉴定及群体遗传学研究提供提供科学依据。     

髌骨矢状面截骨术对髌骨倾斜病理应力分布的生物力学影响

目的：研究髌骨矢状面截骨术对髌骨倾斜病理应力分布的影响。方法：采用手术方法将七具新鲜人尸体膝关节标本的髌骨外侧支持带紧缩，造成髌骨过度外侧倾斜，然后进行四个不同截骨角的髌骨矢状面截骨术。股四头肌腱加载200N。分别于正常状态、髌骨倾斜、截骨5°、10°、15°、20°六种工况下，应用压敏片测量髌股关节接触压力与面积。摄屈膝45°Merchant髌骨轴位片，测量髌骨倾斜角，了解髌骨倾斜程度。结果与结论：髌骨倾斜后，髌骨内侧接触面积与压力均减少，外例接触面积与压力均增加，屈膝30°时最显著。截骨10°以上，明显改善了髌骨倾斜的应力分布，其中截骨15°改善较为理想。本实验结果为临床上髌骨矢状面截骨术中截骨角的选择提供了可靠依据。     

陕西株庚型肝炎病毒(GBV-C/HGV )RNA NS3区 cDNA(4248nt～4465nt)的扩增、克隆和序列分析

目的　了解陕西株庚型肝炎病毒 (HGV,RNA/ GBV-C)的核苷酸序列特点 .方法　从陕西省西安市两位非甲、乙、丙、丁、戊型肝炎患者的血清中 ,应用反转录及套式 PCR技术 ,从血清中提取 RNA,经特异性的反转录引物 P4反转录成c DNA,以此为模板分别用 P3,P4及 P1 ,P2 两对引物进行PCR扩增 ,扩增到 2 18bp的 HGV RNA NS3区部分基因 ,将其克隆入 Pin Point TMXal- T载体 ,挑选阳性克隆并进行了序列分析 .结果　 SG2 与 HGV的核苷酸同源性分别为 85 .6 4%与84.48% ;与 GBV- C的核苷酸同源性为 86 .2 1%与 84.48% ,其二者之间同源性为 97.13% ;二者与 HGV的氨基酸同源性分别为 98.2 8%和 93.10 % ,与 GBV- C的氨基酸同源性也为98.2 8% ,93.10 % ,二者之间的氨基酸同源性达 94.83% .结论　庚型肝炎病毒 NS3区核苷酸同源性较高 ,同义突变率也较高 ,可能是一个对其生存环境较为适应的病毒 .     

Synthesis and Study of Copolymers Bearing Two Coumarin Side Groups in Monomer Unit: Toward Photoalignment of Liquid Crystals

Photodimerization of coumarin derivatives in photoactive polymers under linearly polarized UV (LPUV) light irradiation is a photochemical reaction often used to prepare the surface alignment layer that can orient liquid crystals (LCs) due to the anisotropic interfacial interactions. Herein, the synthesis of a series of novel coumarin-containing copolymers and their use for the photoalignment surface layer of LCs is reported. These copolymers have the particular feature of bearing two coumarin side groups in each monomer unit, which is designed to have a high content of the chromophores. The alignment of LCs induced by the photoalignment layers of the coumarin-containing copolymers is investigated. It is found that the photoalignment layers can effectively induce orientation of LC molecules along the direction of the UV light polarization used to prepare the surface layers, with an order parameter of around 0.5 achieved by adjusting the preparation conditions. Moreover, the electro-optical behaviors of LC cells made with the photoalignment layers are investigated, confirming the alignment of LCs without the use of rubbed surfaces. Optically inscribing the photoalignment layer for nonuniform and organized LC alignment is also demonstrated.     

Effect of hyperventilation on brain tissue oxygenation and cerebrovenous PO2 in rats

Previous studies have shown that cortical tissue oxygenation is impaired during hyperventilation. However, it is important to quantify the effect of hyperventilation on brain tissue PO(2) and cerebrovenous PO(2) simultaneously especially since cerebral venous oxygenation is often used to assess brain tissue oxygenation. The present study was designed to measure the sagittal sinus PO(2) (PvO(2)), brain tissue PO(2) in the thalamus (PtO(2)), and brain temperature (Bt) simultaneously during acute hyperventilation. Isoflurane-anesthetized rats were hyperventilated for 10 min during which time the arterial carbon dioxide tension (PaCO(2)) dropped from 40.3+4.9 mmHg to 23.5+2.8 mmHg. PtO(2) declined from 26.0+/-4.2 mmHg to 14.8+/-5.2 mmHg (P=0.004) while brain temperature decreased from 36.5+0.3 degrees C to 36.2+0.3 degrees C (P=0.02). However, PvO(2) and arterial blood pressure (BP) did not change during hyperventilation. The maintenance of PvO(2) when perfusion is thought to decline and PtO(2) decreases suggests that there may be a diffusion limitation, possibly due to selective perfusion. Therefore, cerebrovenous PO(2) may not give a good assessment of brain tissue oxygenation especially in conditions of acute hyperventilation, and deeper brain regions other than the cortex also show impaired tissue oxygenation following hyperventilation.     

上矢状窦旁中后1/3脑膜瘤术中回流静脉的保护研究

目的探讨上矢状窦中后1/3脑膜瘤术中保护回流静脉的方法及意义,为确保手术成功提供参考依据。方法回顾性分析本院神经外科2011年8月至2013年8月收治的50例上矢状窦旁中后1/3脑膜瘤患者的临床资料,按照是否保护回流静脉分为观察组(36例)和对照组(14例)。观察组患者行静脉磁共振血管成像(MRV)检查,明确上矢状窦通畅程度与脑膜瘤周边静脉回流代偿情况,术中尽量保护回流静脉及正常脑组织,妥善处理受累矢状窦。对照组患者采用传统手术方式治疗,未评价矢状窦通畅情况,未保护回流静脉。依据Simpson标准评价肿瘤切除程度,比较两组患者肿瘤全切率、死亡率、对症治疗及随访情况。结果两组患者均顺利完成手术,观察组患者肿瘤全切除34例(94.44%),对照组患者肿瘤全切除10例(71.43%),两组均未出现死亡病例,观察组患者手术效果明显优于对照组,差异具有显著性(P<0.05)。结论上矢状窦中后1/3脑膜瘤术前行MRV检查,术中保护回流静脉可提高肿瘤全切除率,改善患者的生存质量。