The limited molecular classifications and disease signatures of osteoarthritis (OA) impede the development of prediagnosis and targeted therapeutics for OA patients. To classify and understand the subtypes of OA, we collected three types of tissue including cartilage, subchondral bone, and synovium from multiple clinical centers and constructed an extensive transcriptome atlas of OA patients. By applying unsupervised clustering analysis to the cartilage transcriptome, OA patients were classified into four subtypes with distinct molecular signatures: a glycosaminoglycan metabolic disorder subtype (C1), a collagen metabolic disorder subtype (C2), an activated sensory neuron subtype (C3), and an inflammation subtype (C4). Through ligand-receptor crosstalk analysis of the three knee tissue types, we linked molecular functions with the clinical symptoms of different OA subtypes. For example, the Gene Ontology functional term of vasculature development was enriched in the subchondral bone-cartilage crosstalk of C2 and the cartilage-subchondral bone crosstalk of C4, which might lead to severe osteophytes in C2 patients and apparent joint space narrowing in C4 patients. Based on the marker genes of the four OA subtypes identified in this study, we modeled OA subtypes with two independent published RNA-seq datasets through random forest classification. The findings of this work contradicted traditional OA diagnosis by medical imaging and revealed distinct molecular subtypes in knee OA patients, which may allow for precise diagnosis and treatment of OA.

This study suggests that GB may provide better radiographic and clinical outcomes than MR when used to determine mechanical rotation in TKAs. Cite this article: Bone Joint J 2017;99-B:151-8.

BackgroundOver the past few decades, more and more articles about total hip arthroplasty have been published. We noticed, however, little is known about the characteristics and qualities of these studies.MethodsThe databases of Web of Science Core Collection, BIOSIS Citation Index, MEDLINE, etc. were utilized for the identification of articles published from 1990 to May 2019. Total hip arthroplasty–related articles were identified, and the 100 most cited articles were selected for subsequent analysis of citation count, citation density (citations/article age), authorship, theme, geographic distribution, time-related flux, level of evidence, and network analysis.ResultsThe selected 100 articles were published mainly in the 1990s (46%) and 2000s (47%) with almost equal amount. Citations per article ranged from 994 to 191. Leading countries were the USA followed by Canada, England, and Sweden, all located in North America and Western Europe. The most highlighted study themes were postoperative thrombosis and surgical methods and materials. The most common level of evidence was level III (35%). The network analysis connoted that radiography, acetabulum, reoperation, and bone cement had a high degree of centrality in the 1990s, while cement had a high degree of centrality in the 2000s and 2010s.ConclusionsThe time, area, and theme distribution of the top 100 most cited articles in the total hip arthroplasty have been thoroughly analyzed. It is noticeable that postoperative thromboembolism currently plays a major role in the field of total hip arthroplasty researches. However, most of them focus on the effectiveness of different treatments and drugs; little is known about its underlying mechanisms and influencing factors.

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BackgroundThe purpose of this study was to document the clinical and radiographic results of a consecutive series of patients with ankylosing spondylitis (AS) who had undergone bilaterally primary THA using non-cemented components.MethodsTwenty-six hips of 13 patients with bilateral ankylosis of the hip caused by AS were converted to THA from January 2000 to January 2008. The mean age of the patients was 33.7 years (range, 22-57 years). There were 11 males and 2 females. All the patients had bilateral bony ankylosis with 0° range of motion. The average Harris Hip Scores (HSS) was 22.1 (10–38).ResultsAt a mean follow-up of 128.4 months, the mean HSS at the latest follow-up examination was 91.7 points (range, 75-98 points). All the patients reported marked relief of painful symptoms. Three (11.5%) of the 26 hips were outside the Lewinnek acetabular cup inclination safe range, and 5 (19.2%) of the 26 hips were outside the Lewinnek acetabular cup anteversion safe range. The probability of survival of the prostheses was 100% at 5 years and 92.3% at 10 years, but it dropped sharply to 73.1% at 13 years.ConclusionCementless THA is a worthwhile treatment for the osseous ankylosed hip joint caused by AS. Newfound mobility, maneuverability, and improved ability to sit comfortably were the outcomes that alleviated the patients’ daunted morale. However, the technically demanding nature of the procedure should not be underestimated.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-344) contains supplementary material, which is available to authorized users.

Although solid Au is usually most stable as a face-centered cubic (fcc) structure, pure hexagonal close-packed (hcp) Au has been successfully fabricated recently. However, the phase stability and mechanical property of this new material are unclear, which may restrict its further applications. Here we present the evidence that hcp → fcc phase transformation can proceed easily in Au by first-principles calculations. The extremely low generalized-stacking-fault (GSF) energy in the basal slip system implies a great tendency to form basal stacking faults, which opens the door to phase transformation from hcp to fcc. Moreover, the Au lattice extends slightly within the superficial layers due to the self-assembly of alkanethiolate species on hcp Au (0001) surface, which may also contribute to the hcp → fcc phase transformation. Compared with hcp Mg, the GSF energies for non-basal slip systems and the twin-boundary (TB) energies for and twins are larger in hcp Au, which indicates the more difficulty in generating non-basal stacking faults and twins. The findings provide new insights for understanding the nature of the hcp → fcc phase transformation and guide the experiments of fabricating and developing materials with new structures.

This study demonstrates that uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems when used for reverse total shoulder arthroplasty.

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