Impact of joint line orientation on clinical outcomes in bilateral Oxford mobile-bearing unicompartmental knee arthroplasty

BackgroundJoint line orientation angle (JLOA) is the angle between the knee joint line and the floor. It has been reported to be related to postoperative outcome after TKA. Regarding unicompartmental knee arthroplasty (UKA), although it can be horizontal after UKA because it is a resurfacing surgery, there are few reports about the JLOA after UKA and its impact on clinical outcomes.PurposeThe purpose of this study was to reveal the relationship between JLOA and clinical outcome after UKA.MethodsThis study included 106 knees in 53 consecutive patients with osteoarthritis who underwent simultaneous bilateral mobile-bearing UKA. Their pre- and postoperative JLOAs were measured by full-leg-length standing coronal radiographs. We also evaluated the tibial component height (TCH) as the factor which we assumed could influence JLOA. We analyzed the patients’ JLOAs, TCHs and clinical outcomes.ResultsPre- and postoperative JLOA were 0.4 ± 2.4° and 2.7 ± 2.6°, respectively. The JLOA significantly tilted medially (P < 0.0001). The JLOA significantly negatively correlated with the improvement of the clinical outcomes (Oxford Knee Score (OKS): r = 0.40, P < 0.0001, Knee Society Knee Score (KSKS): r = 0.25, P < 0.01, Knee Society Function Score (KSFS): r = 0.22, P = 0.02). The TCH showed a positive correlation with postoperative JLOA and with the postoperative JLOA change (r = 0.45, P < 0.001; r = 0.25, P < 0.01, respectively).ConclusionThe JLOA significantly tilted medially after UKA. An excessive medial tilt of the JLOA was associated with poorer postoperative outcomes of UKA. It is therefore recommended to keep the JLOA horizontal and to avoid a lower tibial cut.     

Association of QRS-T angle and Late Gadolinium Enhancement in patients with a Clinical Suspicion of Myocarditis

Objective: To investigate the association of a wide QRS-T angle on the surface ECG and late gadolinium enhancement on contrast-enhanced cardiovascular magnetic (CMR) imaging in patients with clinically suspected myocarditis.Background: Diagnosis and risk stratification in patients with suspected myocarditis is particularly challenging due to a great spectrum of clinical presentations. Late gadolinium enhancement (LGE) visualizes myocardial necrosis and fibrosis in patients with biopsy-proven myocarditis. The presence or absence of late gadolinium enhancements in these patients is prognostically meaningful. The QRS-T angle from the surface ECG, on the other hand, may serve as a simple and easily available risk marker in suspected myocarditis.Methods: We enrolled 97 consecutive patients that were referred to CMR imaging for a clinical suspicion of myocarditis. All patients obtained a standardized digital 12-lead ECG for the calculation of the QRS-T angle and underwent contrast-enhanced CMR imaging. Patients were divided into two groups according to the absence or presence of LGE on CMR.Results: 78 of 97 patients with suspected myocarditis had LGE on CMR. Patients with LGE had wider QRS-T angles as compared to the patient group without LGE (53.95-47.5 vs. 26.2-21.2; p<0.001). The sensivity, specificity, negative predictive value and positive predictive value for a QRS-T angle above 90 degrees for LGE positive myocarditis were 16.5%, 100%, 24.7%, and 100%, respectively.Conclusion: A wide QRS-T angle of 90 degrees or more is linked to myocardial fibrosis or necrosis (late gadolinium enhancement) in patients with suspected myocarditis.     

Canine cruciate ligament ruptures: Implications for financial costs and human health

The cranial cruciate ligament (CCL) in dogs is homologous to the anterior cruciate ligament (ACL) in humans. Factors that place an individual at-risk for noncontact ruptures are not clearly defined in humans or dogs. Cyclic variation in human females as well as early spay/neuter in canines has frequently implicated hormonal variation, however these factors do not fully explain the human dimorphic or canine breed rupture rates. The present study examined dogs as a proxy model for humans to better understand the covariance. A random clinical data sample from the Oklahoma State University Veterinary Hospital was obtained on (n = 29) CCL surgical cases and nonsurgical (n = 28) controls. A statistical test for association of spay/neuter with CCL rupture was significant (chi-square = 21.7, p < .01). Sex balance between the groups was not significantly (p > .01) different. Data on other variables related to morphometric variability such as the tibial plateau angle was not available on the nonsurgical sample and comparisons could only be made to values from the literature. Though there may have been sample bias, this preliminary study found that more large than small dogs were represented in the surgical sample. Our results also support the claim that spayed/neutered dogs are more likely to rupture their CCL than intact dogs. Given the high costs of surgical repair, both for canines and humans, we argue for multivariate studies that investigate the interaction of variables in a larger subject sample which can provide comparable data on all parameters.     

Association between ankle angle at initial contact and biomechanical ACL injury risk factors in male during self-selected single-leg landing

BackgroundIncreasing the ankle plantar-flexion angle at initial contact (IC) during landing reduces the impact features associated with landing, such as the vertical ground reaction force and loading rate, potentially affecting the risk of anterior cruciate ligament (ACL) injury. However, the relationships between the ankle plantar-flexion angle at IC and the previously identified biomechanical factors related to noncontact ACL injury have not been studied.Research questionThus, the purpose of this study was to determine whether significant relationships exist between the ankle plantar-flexion angle at IC and the biomechanical factors related to noncontact ACL injury.MethodsThe peak anterior tibial shear force, peak external knee valgus moment, peak knee valgus angle, and combined peak external knee valgus plus tibial internal rotation moments were measured in 26 individuals while performing self-selected, single-leg landing. Pearson correlation analyses were performed to assess the relationships between the ankle plantar-flexion angle at IC and the biomechanical factors mentioned above.ResultsThe greater ankle plantar-flexion angle at IC was related to smaller the peak knee valgus moment (r = −0.5, p = 0.009) and the combined peak knee valgus plus internal rotation moments (r = −0.58, p = 0.001).SignificanceThese results suggest that large ankle plantar-flexion angle at IC might be associated with lesser loading of the knee frontal plane and altering the self-selective ankle angle may result in biomechanical changes associated with ACL injury risk.     

华南人胫骨平台后倾角的三维测量及临床意义

目的　测量华南成人正常胫骨平台后倾角数据,为改进及设计适合中国人（尤其华南人）的膝关节假体和在全膝关节置换术中行合理的胫骨截骨,提供参考和依据。 方法　对80例华南志愿者膝关节行薄层螺旋CT扫描后,用Mimics软件重建出三维模型,导入Unigraphics NX软件中测量其胫骨内外侧平台的后倾角。 结果　胫骨内侧平台后倾角,左侧（8.47±3.42）°,右侧（7.84±3.30）° ;男性（7.69±　2.89）°,女性（8.62±3.74）°;平均（8.16±3.37）°;胫骨外侧平台后倾角,左侧（6.89±3.42）°,右侧（6.82±2.78）°;男性（6.84±2.82）°,女性（6.87±3.01）°;平均（6.85±2.90）°。胫骨内、外侧平台后倾角在不同性别、侧别间无显著性差异（P＞0.05）,但胫骨内侧平台后倾角明显大于胫骨外侧平台后倾角（P＜0.05）。 结论　华南成人正常胫骨平台后倾角的个体差异较大,均值小于国内其他地区报道和国外大多数同类研究。     

Persistent inhibition of Candida albicans biofilm and hyphae growth on titanium by graphene nanocoating

ObjectivesCandida albicanscolonizes biomaterial surfaces and are highly resistant to therapeutics. Graphene nanocoating on titanium compromises initial biofilm formation. However, its sustained antibiofilm potential is unknown. The objective of this study was to investigate the potential of graphene nanocoating to decrease long-term fungal biofilm development and hyphae growth on titanium.MethodsGraphene nanocoating was deposited twice (TiGD) or five times (TiGV) on grade 4 titanium with vacuum assisted technique and characterized with Raman spectroscopy and atomic force microscope. The biofilm formation and hyphae growth of C. albicans was monitored for seven days by CFU, XTT, confocal, mean cell density and scanning electronic microscopy (SEM). Uncoated titanium was the Control. All tests had three independent biological samples and were performed in independent triplicates. Data was analyzed with one- or two-way ANOVA and Tukey's HSD (α = 0.05).ResultsBoth TiGD and TiGV presented less biofilms at all times points compared with Control. The confocal and SEM images revealed few adhered cells on graphene coated samples, absence of hyphae and no features of a mature biofilm architecture. The increase in number of layers of graphene nanocoating did not improve its antibiofilm potential.SignificanceThe graphene nanocoating exerted a long-term persistent inhibitory effect on the biofilm formation on titanium. The fewer cells that were able to attach on graphene coated titanium were scattered and unable to form a mature biofilm with hyphae elements. The findings open opportunities to prevent microbial attachment and proliferation on implantable materials without the use of antibiotics.     

Dithieno[3,2‐b:2′,3′‐d]pyrrole and Benzothiadiazole‐Based Semicrystalline Copolymer for Photovoltaic Devices with Indene‐C60 Bisadduct

A semicrystalline low‐bandgap polymer (PDTPBT) based on alternating dithienopyrrole and benzothiadiazole moieties as a pair of the indene‐C₆₀ bisadduct (ICBA) for polymeric solar cells is reported. The lowest unoccupied molecular orbital (LUMO) level of PDTPBT is measured to be ?3.47 eV, ensuring sufficient energy offset for photoinduced charge transfer to ICBA. Photovoltaic cells are fabricated with ICBA and [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) as an acceptor. By replacing PC₇₁BM with ICBA, the open‐circuit voltage is increased by 0.23 V and the resulting power conversion efficiency is improved from 1.17% to 1.71%. To optimize the ICBA‐based devices, crystalline low‐bandgap structures should be designed carefully as a pair of ICBA by considering the energy‐level offset for charge separation and crystalline interchain ordering, for minimizing the intercalated ICBAs inside the polymer domain.

     

Determination of Poly(4,4′‐diphenylsulfonyl terephthalamide) Crystalline Structure Via WAXD and Molecular Simulations

The crystal structure of poly(4,4′‐diphenylsulfonyl terephthalamide) (pt‐PSA) is studied by X‐ray diffraction and molecular simulation. Although the number of observed reflections is limited to warrant a precise determination of the unit cell structure and symmetry, a reasonable monoclinic unit cell is suggested with dimensions of a = 0.645 nm, b = 0.488 nm, c = 3.010 nm, and γ = 122.5°. A twofold molecule with two monomeric units forming a large zigzag conformation satisfies the X‐ray diffraction data. A layer structure is formed in the crystal phase, which is stabilized by the hydrogen bond between ? NH and ? C?O and the parallel‐displaced π–π stacking from the distortional coplanarity of the benzene rings and amide group.

     

Effect of releasing quadratus lumborum muscle on hip and knee muscle length in asymptomatic individuals

BackgroundQuadratus lumborum muscle (QL) is one of several muscles subject to tightness and relevant to symptoms in the back and hip. Although releasing the tight QL seems to resolve these symptoms in clinic, no study has investigated the effects of such releasing on the length of the hip and knee muscles.ObjectiveTo compare muscle length of the hip and knee joints between pre- and post-releasing the QL.MethodsA quasi-experimental design (one-group pretest-posttest design) was conducted. Thirty asymptomatic participants with mean age of 20.40 years took part in the study. An examiner assessed the participants’ pelvic transverse gliding movement in standing and rotation of the upper trunk in supine to perceive the end feel of tissue resistance. The side with perceived more muscle tension was selected for receiving muscle release. Before manually releasing the QL, the participant was in the modified Thomas test position and pre-test range of motion (ROM) of hip flexion, hip abduction, and knee flexion angles was measured using a standard goniometer. After releasing the QL, the aforementioned angles were measured for post-test ROM.ResultsThe hip flexion angle was significantly reduced after releasing the QL (p < 0.05), whereas no statistically significant differences were found for the other 2 angles (p > 0.05).ConclusionThe length of iliopsoas muscle was increased after releasing the QL. The findings may be due to continuous fascial connection and similar attachment of the origins of these 2 muscles.Clinical trial registration numberNCT03016559.