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Objective: Recent advances in single‐cell RNA sequencing technology have improved our understanding of the immunological landscape of rheumatoid arthritis (RA). We aimed to stratify the synovium from East Asian patients with RA by immune cell compositions and gain insight into the inflammatory drivers of each synovial phenotype. Methods: Synovial tissues were obtained from East Asian patients in Japan with RA (n = 41) undergoing articular surgery. The cellular composition was quantified by a deconvolution approach using a public single‐cell–based reference. Inflammatory pathway activity was calculated by gene set variation analysis, and chromatin accessibility was evaluated using assay of transposase accessible chromatin–sequencing. Results: We stratified RA synovium into three distinct subtypes based on the hierarchical clustering of cellular composition data. One subtype was characterized by abundant HLA‐DRAhigh synovial fibroblasts, autoimmune‐associated B cells, GZMK+GZMB+ CD8+ T cells, interleukin (IL)1‐β+ monocytes, and plasmablasts. In addition, tumor necrosis factor (TNF)‐α, interferons (IFNs), and IL‐6 signaling were highly activated in this subtype, and the expression of various chemokines was significantly enhanced. Moreover, we found an open chromatin region overlapping with RA risk locus rs9405192 near the IRF4 gene, suggesting the genetic background influences the development of this inflammatory synovial state. The other two subtypes were characterized by increased IFNs and IL‐6 signaling, and expression of molecules associated with degeneration, respectively. Conclusion: This study adds insights into the synovial heterogeneity in East Asian patients and shows a promising link with predominant inflammatory signals. Evaluating the site of inflammation has the potential to lead to appropriate drug selection that matches the individual pathology. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to clarify the effect of gait protocols and postoperative shoes on forefoot load in preoperative patients for forefoot disorders and compare footwear comfort between different types of postoperative shoes., Methods: Fourteen subjects scheduled to undergo forefoot surgeries were recruited. The maximum force under the forefoot region was measured during 10 m straight walking in two gait patterns with six different shoe types. Visual analogue scale (VAS) scores for footwear comfort, subjective lower thigh pain, and electrical activities of lower thigh muscles were also evaluated., Results: The body weight-normalized maximum force under the forefoot region significantly decreased in step-to gait compared to normal gait regardless of the shoe types used. Under the same gait condition, no significant difference was observed in the forefoot off-loading effect between the different shoe types used. Significantly worse VAS scores, significantly higher tibialis anterior muscle activities, and complaints of lower thigh pain were demonstrated in the gait with the reverse camber shoe., Conclusions: Gait protocol of step-to gait had more forefoot off-loading effect than postoperative shoes. The forefoot off-loading effect did not differ among the postoperative shoes, suggesting that postoperative shoes can be selected with an emphasis on footwear comfort., (© Japan College of Rheumatology 2021. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: Patients with rheumatoid arthritis (RA) are at increased risk of falling; therefore, fall prevision and prevention are critical. The present study aimed to evaluate the ability of physical performance assessments to discriminate between RA patients with and without a history of falling., Methods: Fifty patients with RA were divided into two groups according to the presence or absence of a history of falls within the previous 1 year. Physical performance was assessed using the short physical performance battery (SPPB), which consists of the timed standing balance, gait speed, and chair stand tests. Standing balance was also assessed as postural sway using a force platform in several positions including standing with both feet together, semitandem, and tandem. Backgrounds, SPPB, and postural sway were compared between the two groups., Results: Fourteen patients (28%) reported one or more falls within the previous year. There were no significant intergroup differences in baseline characteristics or SPPB score. The group with a history of falls had significantly longer measured time for the 5-repetition chair stand test and significantly longer postural sway in the semitandem position. The discriminate analysis revealed that 5-repetition chair stand test or its combination with postural sway in the semitandem position significantly discriminated between fallers and non-fallers., Conclusion: Numerical evaluation of the chair stand test and postural sway in the semitandem position seems more appropriate than SPPB for assessing the fall risk of patients with RA.

Objectives: The purpose of this study was to clarify the effect of disease activity on recurrent deformities after resection arthroplasty for forefoot deformities in patients with rheumatoid arthritis (RA)., Methods: This study included 83 feet in 58 patients with RA who underwent resection arthroplasty of all metatarsal heads, with a minimum follow-up of 2 years. The patients' demographic characteristics, preoperative radiographic findings, and RA disease activity evaluated using the 28-joint disease activity score based on the erythrocyte sedimentation rate (determined preoperatively and at the final follow-up) were compared between feet with and without postoperative recurrent deformities of the toes. Recurrent deformities were assessed separately for the hallux and lesser toes., Results: Recurrence in the hallux and lesser toes occurred in 23 feet (27.7%) and 13 feet (15.7%), respectively. With respect to recurrent hallux deformity, only the preoperative severity of hallux deformity was associated with recurrence. On the other hand, postoperative deformity of the lesser toes was positively associated with disease activity alone and not with other preoperative factors., Conclusion: Postoperative control of RA disease activity was associated with recurrent deformity of the lesser toes but not that of the hallux after resection arthroplasty of all metatarsals for rheumatoid forefoot deformities.

Objectives: There have been few reports on factors affecting bone union after metatarsal osteotomies. The purpose of this study was to clarify the factors affecting bone union after distal shortening oblique osteotomy of the lesser metatarsals. Methods: Patients who underwent distal shortening oblique osteotomy of the lesser metatarsals were retrospectively investigated. Failure to achieve bone union at 6 months after surgery was defined as delayed union. Background characteristics and radiographic measurements were compared between patients with and those without delayed union, and factors affecting bone union were assessed using multivariate analysis. Results: Among 204 toes in 58 patients evaluated in this study, delayed union occurred in 28%. In multivariate analysis, corticosteroid use (odds ratio (OR), 3.68; 95% confidence interval (CI), 1.65-8.16; p < .01), larger preoperative overlap between the metatarsal and the proximal phalanx (OR, 1.11 (per 1 mm increase); 95% CI, 1.02-1.21; p = .02), and larger gap at the osteotomy site (OR, 3.02 (per 1 mm increase); 95% CI, 1.76-5.16; p < .01) were identified as independent risk factors of delayed union. Conclusion: The identified risk factors of delayed union after distal shortening metatarsal osteotomies were corticosteroid use, preoperative overlap between the metatarsal and the proximal phalanx, and a gap at the osteotomy site.