Causal relationship between serum metabolites and juvenile idiopathic arthritis: a mendelian randomization study.

BACKGROUND: Juvenile Idiopathic Arthritis (JIA) is a condition that occurs when individuals under the age of 16 develop arthritis that lasts for more than six weeks, and the cause is unknown. The development of JIA may be linked to serum metabolites. Nevertheless, the association between JIA pathogenesis and serum metabolites is unclear, and there are discrepancies in the findings across studies. METHODS: In this research, the association between JIA in humans and 486 serum metabolites was assessed using genetic variation data and genome-wide association study. The identification of causal relationships was accomplished through the application of univariate Mendelian randomization (MR) analysis. Various statistical methods, including inverse variance weighted and MR-Egger, were applied to achieve this objective. To ensure that the findings from the MR analysis were trustworthy, a number of assessments were carried out. To ensure the accuracy of the obtained results, a range of techniques were utilised including the Cochran Q test, examination of the MR-Egger intercept, implementation of the leave-one-out strategy, and regression analysis of linkage disequilibrium scores. In order to identify the specific metabolic pathways associated with JIA, our primary objective was to perform pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes. RESULTS: Two-sample summary data MR analyses and sensitivity analyses showed that five metabolites were significantly causally associated with JIA, including two risk factors-kynurenine (odds ratio [OR]: 16.39, 95% confidence interval [CI]: 2.07-129.63, p = 5.11 × 10- 6) and linolenate (OR: 16.48, 95% CI: 1.32-206.22, p = 0.030)-and three protective factors-3-dehydrocarnitine (OR: 0.32, 95% CI: 0.14-0.72, p = 0.007), levulinate (4-oxovalerate) (OR: 0.40, 95% CI: 0.20-0.80, p = 0.010), and X-14,208 (phenylalanylserine) (OR: 0.68, 95% CI: 0.51-0.92, p = 0.010). Furthermore, seven metabolic pathways, including α-linolenic acid metabolism and pantothenate and CoA biosynthesis, are potentially associated with the onset and progression of JIA. CONCLUSION: Five serum metabolites, including kynurenine and 3-dehydrocarnitine, may be causally associated with JIA. These results provide a theoretical framework for developing effective JIA prevention and screening strategies.

Improved radiographic outcomes and decreased complications rate on the femoral side can be achieved by a novel designed whole-process robotic assisted hip system for total hip arthroplasty: a prospective randomized controlled trial.

Postoperative complications due to inaccurate prosthesis positioning are the main causes of early revision. The aim of this study was to (1) determine whether novel designed whole-process robotic assisted hip system allowed better radiographic outcomes and lower complications risk on the femoral side particularly stem subsidence compared to conventional THA, and to (2) identify the comparison of early clinical outcomes. 72 patients were initially enrolled and randomly divided into 2 groups. Finally, only 65 patients (31 RA-THAs, 34 C-THAs) were analyzed who had full 18-month follow-up data. Radiographic follow-up was performed at immediate and 6-month postoperatively, while clinical follow-up at 18-month postoperatively. Stem-related radiographic outcomes, femoral side complications and clinical scores were compared. The robotic arm allowed better radiographic outcomes of the femoral side, including a higher canal fill ratio (CFR) at B1 (P = 0.040), more neutral stem alignment (P = 0.029), lower subsidence (P = 0.023) and lower leg length discrepancy (LLD) (P = 0.010). In addition, low CFR at B1 (P = 0.001) was found the risk factor for subsidence. However, early clinical outcomes were consistent between both groups. The novel designed whole-process robotic assisted hip system covers both femoral and acetabular side operations. It allows accurate and safe manipulation of femoral side, including better stem-related radiographic outcomes and lower risk of subsidence and LLD. However, no advantage of robotic system in early clinical score was identified. Clinical trial registration number: ChiCTR2100044124.

A new designed full process coverage robot-assisted total hip arthroplasty: a multicentre randomized clinical trial.

OBJECTIVE: To compare the effect of a new complete robot-assisted total hip arthroplasty (RA-THA) with that of the manual total hip arthroplasty (MTHA) and to verify the accuracy and safety of the former. METHODS: Overall, 148 patients were enroled from 3 March 2021 to 28 December 2021 in this study and classified into RA-THA ( n =74 patients) and MTHA ( n =74 patients) groups. The sex, age, operative side, BMI, diagnosis, other basic information, operative time, acetabular prosthesis anteversion and inclination, femoral prosthesis anteversion and angulation, femoral prosthesis filling rate, leg length discrepancy (LLD), Harris hip score, and visual analogue scale (VAS) score of the two groups were compared. RESULTS: No significant differences were observed in the two groups regarding sex, age, operative side, BMI, diagnosis, Harris hip score, VAS score, acetabular inclination, acetabular prosthesis anteversion, femoral prosthesis anteversion, combined anteversion, and femoral prosthesis filling rate ( P >0.05). The operative time was significantly longer in the RA-THA group than in the MTHA group (106.71±25.22 min vs. 79.42±16.16 min; t=7.30, P <0.05). The femoral angulation (1.78°±0.64°) and LLD (2.87±1.55 mm) in the RA-THA group were significantly lesser than those in the MTHA group (2.22°±1.11° and 5.81±6.27 mm, respectively; t=-2.95 and t=-3.88, P <0.05). CONCLUSION: The complete RA-THA has some advantages over the traditional procedure in restoring the lower limb length and controlling the femoral prosthesis angulation. Thus, this study verifies the accuracy and safety of the robot-assisted system.

Construction and expression of Mycobacterium tuberculosis fusion protein SHR3 and its immunogenicity analysis in combination with various adjuvants.

Tuberculosis (TB) today remains the leading cause of global deaths due to infectious bacterial pathogens. The Bacillus Calmette-Guérin (BCG) vaccine is the only vaccine clinically used to prevent TB. However, its limitations in preventing latent infection and TB reactivation mean that it does not provide comprehensive protection. In this study, we successfully constructed and expressed the multistage fusion protein, SHR3, and used whole blood IFN-γ release assay (WBIA) with flow cytometry to detect antigen specificity, further confirmed by enzyme-linked immunosorbent assay (ELISA). SHR3 and its subfractional proteins stimulated the level of IFN-γ production by lymphocytes from M. tb-infected patients, inducing the production of single-positive and double-positive CD4+ and CD8+ T cells with IFN-γ and IL-2, at levels significantly higher than those of healthy controls. The fusion protein and complex adjuvant group (SHR3/DMT) induced mice to produce significantly higher levels of IgG antibodies and their subclasses, with IgG2a/IgG1 results showing a convergent Th1-type response; mice in the BCG + SHR3/DMT group induced secretion of the highest levels of IL-2, and TNF-α, irrespective of stimulation with purified protein derivative or SHR3. These findings suggest that SHR3/DMT could be a potential subunit vaccine candidate that may serve as an effective booster vaccine after BCG primary immunization.

Accuracy and safety of a new robotic arm for both femoral and acetabular side in total hip arthroplasty: a cadaveric study.

BACKGROUND: To investigate the accuracy and safety of a newly constructed robotic arm which can cover the whole process of THA, we performed a series of robot-assisted total hip replacement on the cadaver. METHODS: Fifteen frozen cadaveric specimens (30 hips) were used for this study. In this investigation, united hip system and Longwell robotic-assisted system were used. The entire lower limb was CT scanned prior to surgery. The 3D model was produced based on CT data; the site of the prosthesis, including acetabular anteversion, inclination angle, and the position of femoral prosthesis, was planned. With the assistance of a robotic arm, the surgeon changed the parameters based on the preoperative plan and the actual condition during surgery, and completed the whole procedure. Following surgery, we measured the acetabular anteversion angle, acetabular inclination angle, femur anteversion angle, combined anteversion angle, stem angulation, and canal fill ratio. RESULTS: The parameters proved that the acetabular anteversion angle was 16.85 ± 3.00°, the acetabular inclination angle was 40.38 ± 5.37°, femur anteversion angle was 15.90 ± 9.01°, combined anteversion angle was 32.75 ± 9.03°, stem angulation was 1.84 ± 0.99°, and leg length discrepancy was 2.47 ± 1.43 mm. The canal fill ratio (CFR) of femoral prosthesis of osteotomy line in sagittal section is 99.72 ± 1.54% and in coronal section is 62.94 ± 8.91%; below osteotomy line 2.5 cm in sagittal section is 100.00% and in coronal section is 81.48 ± 12.94%; below osteotomy line 7.5 cm in sagittal section is 59.51 ± 12.94% and in coronal section is 89.79 ± 11.13%; femoral shaft isthmus in sagittal section is 56.41 ± 13.80% and in coronal section is 84.95 ± 15.17%. CONCLUSION: The accuracy and safety of this novel robotic arm are suitable for preparing both the acetabular and femoral sides, providing evidence for clinical trial.

Piezo1 transforms mechanical stress into pro senescence signals and promotes osteoarthritis severity.

Osteoarthritis (OA) is a prevalent disease among elderly people and is often characterized by chronic joint pain and dysfunction. Recently, growing evidence of chondrocyte senescence in the pathogenesis of OA has been found, and targeting senescence has started to be recognized as a therapeutic approach for OA. Piezo1, a mechanosensitive Ca2+ channel, has been reported to be harmful in sensing abnormal mechanical overloading and leading to chondrocyte apoptosis. However, whether Piezo1 can transform mechanical signals into senescence signals has rarely been reported. In this study, we found that severe OA cartilage expressed more Piezo1 and the senescence markers p16 and p21. 24 h of periodic mechanical stress induced chondrocyte senescence in vitro. In addition, we demonstrated the pivotal role of Piezo1 in OA chondrocyte senescence induced by mechanical stress. Piezo1 sensed mechanical stress and promoted chondrocyte senescence via its Ca2+ channel ability. Moreover, Piezo1 promoted SASP factors production under mechanical stress, particularly in IL-6 and IL-1ß. p38MAPK and NF-κB activation were two key pathways that responded to Piezo1 activation and promoted IL-6 and IL-1ß production, respectively. Collectively, our study revealed a connection between abnormal mechanical stress and chondrocyte senescence, which was mediated by Piezo1.

Artificial intelligence planning and 3D printing augmented modules in the treatment of a complicated hip joint revision: a case report.

Total hip revision with osseous defects can be very difficult. Artificial intelligence offers preoperative planning, real-time measurement, and intraoperative judgment, which can guide prothesis placement more accurately. Three-dimensional printed metel augment modules which are made according to the individualized osseous anatomy, can fit the osseous defects well and provide mechanical support. In this case, we used AI to plan the size and position of the acetabular cup and 3D-printed augmented modules in a complicated hip revision with an acetabular bone defects, which achieved stable fixation and relieved hip pain postoperatively.

Ochronotic arthropathy effectively treated with total hip and total knee arthroplasty: a case report.

Ochronosis is a rare autosomal recessive disorder of tyrosine metabolism characterized by multilevel spinal degeneration and arthritis of large weight-bearing joints, which is referred to as ochronotic arthropathy. In this case report, we describe diagnosis and treatment of ochronotic arthropathy in a patient who underwent total hip arthroplasty (THA) and total knee arthroplasty (TKA). The Harris hip score was 26 preoperatively and 45, 68, 76, 90, 92, and 94 at 1, 3, 6, 9, 11, and 14 months, respectively, postoperatively. The forgotten joint score (FJS) of the hip was 27.8, 52.8, 81.1, 89.0, 90.6, and 92.4 at 1, 3, 6, 9, 11, and 14 months, respectively, postoperatively. TKA was performed 8 months after THA. The Knee Society Score was 36 before TKA and 74, 82, and 90 at 1, 3, and 6 months, respectively, after TKA. The FJS of the knee was 36.6, 63.9, and 84.5 at 1, 3, and 6 months, respectively, after TKA. The patient's knee range of motion returned to normal, with significant reduction in pain and improved satisfaction levels after TKA. THA and TKA can achieve good clinical outcomes in patients with ochronosis accompanied by severe joint pain.

Genome-wide identification of candidate copy number polymorphism genes associated with complex traits of Tibetan-sheep.

Copy number variation (CNV) is a genetic structural polymorphism important for phenotypic diversity and important economic traits of livestock breeds, and it plays an important role in the desired genetic variation. This study used whole genome sequencing to detect the CNV variation in the genome of 6 local Tibetan sheep groups. We detected 69,166 CNV events and 7230 copy number variable regions (CNVRs) after merging the overlapping CNVs, accounting for 2.72% of the reference genome. The CNVR length detected ranged from 1.1 to 1693.5 Kb, with a total length of 118.69 Mb and an average length of 16.42 Kb per CNVR. Functional GO cluster analysis showed that the CNVR genes were mainly involved in sensory perception systems, response to stimulus, and signal transduction. Through CNVR-based Vst analysis, we found that the CACNA2D3 and CTBP1 genes related to hypoxia adaptation, the HTR1A gene related to coat color, and the TRNAS-GGA and PIK3C3 genes related to body weight were all strongly selected. The findings of our study will contribute novel insights into the genetic structural variation underlying hypoxia adaptation and economically important traits in Tibetan sheep.

Fatigue database of complex metallic alloys.

The past few decades have witnessed rapid progresses in the research and development of complex metallic alloys such as metallic glasses and multi-principal element alloys, which offer new solutions to tackle engineering problems of materials such as the strength-toughness conflict and deployment in harsh environments and/or for long-term service. A fatigue database (FatigueData-CMA2022) is compiled from the literature by the end of 2022. Data for both metallic glasses and multi-principal element alloys are included and analyzed for their statistics and patterns. Automatic extraction and manual examination are combined in the workflow to improve the efficiency of processing, the quality of published data, and the reusability. The database contains 272 fatigue datasets of S-N (the stress-life relation), ε-N (the strain-life relation), and da/dN-ΔK (the relation between the fatigue crack growth rate and the stress intensity factor range) data, together with the information of materials, processing and testing conditions, and mechanical properties. The database and scripts are released in open repositories, which are designed in formats that can be continuously expanded and updated.

The influence of prosthetic positioning and proximal femoral morphology on leg length discrepancy and early clinical outcomes of cementless total hip arthroplasty.

BACKGROUND: Leg length discrepancy (LLD) is a common complication of total hip arthroplasty (THA). However, the relationship between femoral prosthesis filling, proximal femoral morphology, and acetabular prosthesis positioning with postoperative LLD and clinical outcomes is unclear. The aims of this study were to investigate the influence of canal flare index (CFI), canal fill ratio (CFR), center of rotation (COR), and femoral offset (FO) on (1) postoperative LLD; and (2) clinical outcomes in the two stem designs with different coating distribution. METHODS: The study cohort included 161 patients who underwent primary cementless THA between January 2021 and March 2022 with either proximal coating or full coating stems. Multivariate logistic regression was used to assess the effect of CFI, CFR, COR, and FO on postoperative LLD, and linear regression to assess their effect on clinical outcomes. RESULTS: No statistical difference was found in clinical outcomes or postoperative LLD between the two groups. High CFI (p = 0.014), low ΔVCOR (p = 0.012), and Gender (p = 0.028) were found independent risk factors for LLD one day postoperative. High CFI was also an independent risk factor for postoperative subjectively perceived LLD (p = 0.013). CFR at the level of 2 cm below the LT (p = 0.017) was an independent risk factor for Harris Hip Score. CONCLUSIONS: Proximal femoral morphology and acetabular prosthesis positioning but not femoral prosthesis filling affected the LLD. High CFI was an independent risk factor for postoperative LLD and subjectively perceived LLD, and low ΔVCOR was also an independent risk factor for postoperative LLD. Women were susceptible to postoperative LLD.

Senescence-responsive miR-33-5p promotes chondrocyte senescence and osteoarthritis progression by targeting SIRT6.

Osteoarthritis (OA) is a prevalent disease among elderly individuals that is caused by cartilage degeneration. Chondrocyte senescence involved in the development of OA, and antisenescence therapies have been proposed for OA treatment. In our study, we identified the role of a microRNA, miR-33-5p, in promoting chondrocyte senescence and OA progression. miR-33-5p expression was upregulated under senescence conditions. miR-33-5p-mimic transfection can induce cellular senescence, while transfection of a miR-33-5p-inhibitor in chondrocytes alleviated senescence induced by IL-1ß. Moreover, SIRT6 expression was downregulated under IL-1ß treatment, and could be restored by miR-33-5p-inhibitor transfection. Luciferase assays revealed that miR-33-5p targeted the SIRT6 mRNA 3' UTR. In addition, SIRT6 mRNA expression showed negative correlations with senescence and OA degree in human cartilage. Bioinformatic analysis also confirmed the pro-senescence effect of miR-33-5p. Furthermore, periodic intraarticular injection of agomiR-33-5p induced cartilage loss and OA-like cartilage changes. To conclude, we revealed the pro-senescence and cartilage-destructive effect of miR-33-5p, whose expression was elevated under various senescence conditions, and showed that SIRT6 was one of its targets. Therefore, miR-33-5p is a potential therapeutic target for treating OA.

Sirtuins in osteoarthritis: current understanding.

Osteoarthritis (OA) is a common disease characterized by severe chronic joint pain, that imposes a large burden on elderly people. OA is a highly heterogeneous disease, and multiple etiologies contribute to its progression. Sirtuins (SIRTs) are Class III histone deacetylases (HDACs) that regulate a comprehensive range of biological processes such as gene expression, cell differentiation, and organism development, and lifespan. Over the past three decades, increasing evidence has revealed that SIRTs are not only important energy sensors but also protectors against metabolic stresses and aging, and an increasing number of studies have focused on the functions of SIRTs in OA pathogenesis. In this review, we illustrate the biological functions of SIRTs in OA pathogenesis from the perspectives of energy metabolism, inflammation, autophagy and cellular senescence. Moreover, we offer insights into the role played by SIRTs in regulating circadian rhythm, which has recently been recognized to be crucial in OA development. Here, we provide the current understanding of SIRTs in OA to guide a new direction for OA treatment exploration.

Fatigue database of additively manufactured alloys.

Fatigue is a process of mechanical degradation that is usually assessed based on empirical rules and experimental data obtained from standardized tests. Fatigue data of engineering materials are commonly reported in S-N (the stress-life relation), ε-N (the strain-life relation), and da/dN-ΔK (the relation between the fatigue crack growth rate and the stress intensity factor range) data. Fatigue and static mechanical properties of additively manufactured (AM) alloys, as well as the types of materials, parameters of AM, processing, and testing are collected from thousands of scientific articles till the end of 2022 using natural language processing, machine learning, and computer vision techniques. The results show that the performance of AM alloys could reach that of conventional alloys although data dispersion and system deviation are present. The database (FatigueData-AM2022) is formatted in compact structures, hosted in an open repository, and analyzed to show their patterns and statistics. The quality of data collected from the literature is measured by defining rating scores for datasets reported in individual studies and through the fill rates of data entries across all the datasets. The database also serves as a high-quality training set for data processing using machine learning models. The procedures of data extraction and analysis are outlined and the tools are publicly released. A unified language of fatigue data is suggested to regulate data reporting for the fatigue performance of materials to facilitate data sharing and the development of open science.

Prospective randomized controlled trial on the accuracy of prosthesis positioning in total hip arthroplasty assisted by a newly designed whole-process robotic arm.

INTRODUCTION: The purpose of this article is to study whether the newly designed whole-process total hip arthroplasty (THA) robotic arm can improve the accuracy of prosthesis placement in THA. METHOD: In this study, 72 patients undergoing THA were prospectively included and randomly divided into two groups. The experimental group was treated with THA assisted by a newly designed robotic arm. The control group received THA with conventional surgical methods. The imaging data were compared after operation. RESULT: Compared with the conventional operation, the whole-process robotic arm can more accurately place the acetabular prosthesis in the anteversion safe zone of 5 ~ 25°, but in terms of the inclination angle, whether the reference is the safe zone of 30 ~ 50° or 30 ~ 45°, there is no statistical difference between the two groups. The average lower limb length discrepancy (LLLD) in the experimental group was 3.77 ± 8.31 mm longer than contralateral side, while the counterpart in the control group was 8.39 ± 9.11 mm, with significant difference (P = 0.029). The femoral prosthesis was fixed in neutral position in 35 (100%) cases in the experimental group and only 30 (83.3%) in the control group (P = 0.036). There was no significant difference in the recovery of hip offset, femoral anteversion, and canal fill ratio (CFR) between the two groups. CONCLUSION: Robotic arm can improve the accuracy of anteversion of acetabular cup, restore the consistency of the length of lower limbs, and more accurately implant the femoral prosthesis to the neutral position in the coronal position. CLINICAL TRIAL REGISTRATION NUMBER: ChiCTR2100044124 (date of registration: 2021-3-11).

Senescence in osteoarthritis: from mechanism to potential treatment.

Osteoarthritis (OA) is an age-related cartilage degenerative disease, and chondrocyte senescence has been extensively studied in recent years. Increased numbers of senescent chondrocytes are found in OA cartilage. Selective clearance of senescent chondrocytes in a post-traumatic osteoarthritis (PTOA) mouse model ameliorated OA development, while intraarticular injection of senescent cells induced mouse OA. However, the means and extent to which senescence affects OA remain unclear. Here, we review the latent mechanism of senescence in OA and propose potential therapeutic methods to target OA-related senescence, with an emphasis on immunotherapies. Natural killer (NK) cells participate in the elimination of senescent cells in multiple organs. A relatively comprehensive discussion is presented in that section. Risk factors for OA are ageing, obesity, metabolic disorders and mechanical overload. Determining the relationship between known risk factors and senescence will help elucidate OA pathogenesis and identify optimal treatments.

Comparing the Efficacy of Articulating Spacers in Two-Stage Revision for Periprosthetic Joint Infection Following Total Knee Arthroplasty: All-Cement Spacers vs Sterilized Replanted Metal-Polyethylene Spacers.

Purpose: Two-stage revision is the most common treatment for periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). Few studies have compared the clinical efficacy of different articulating spacers. This study compared the outcomes of all-cement articulating spacers and sterilized replanted metal-polyethylene articulating spacers for PJI following TKA. Patients and Methods: In this retrospective observational study, 47 patients who received two-stage revision for PJI following TKA between 2006 and 2020 in our hospital were included. Patients were categorized as receiving an all-cement articulating spacer or a sterilized replanted metal-polyethylene articulating spacer in exclusion. Data on demographics, surgical information, and outcomes were collected in 2021. Results: Forty-seven spacers were identified: all-cement spacer was noted in 23 patients and sterilized replanted spacer in 24. Patients in the all-cement spacer group had shorter operation time (155.87 ± 33.12 vs 189.79 ± 51.21 min; P = 0.0102) and less blood loss (845.22 ± 525.92 vs 1114.50 ± 547.81 mL; P = 0.0427) in exclusion. Patients in the sterilized replanted spacer group had superior interval range of motion (ROM; 61.00 ± 31.94° vs 31.75 ± 33.38°; P = 0.0072), postoperative ROM (85.00 ± 11.11° vs 77.37 ± 9.18°; P = 0.0329) as compared to all-cement spacers, but there was no difference in infection control between 2 groups. Conclusion: The two types of spacers had no difference in the reinfection rate, indicating that both articulating spacers are safe and effective for 2-stage revision. Considering ROM of knee joint, bone loss and cost, sterilized replanted metal-polyethylene spacers are preferred in the treatment of PJI.

Robotic-arm assisted versus conventional technique for total knee arthroplasty: early results of a prospective single centre study.

PURPOSE: The purpose of this study was to compare the early functional outcomes between robotic-arm assisted total knee arthroplasty (RATKA) and conventional manual total knee arthroplasty (TKA). METHODS: This prospective cohort study included 52 patients (26 RATKA and 26 TKA). All procedures were performed by a single experienced surgeon using identical approach and implant designs. Post-operative evaluation consisted of the risks of inflammatory and blood loss, the accuracy of mechanical alignment, post-operative pain, peri-operative and post-operative functional outcomes, and complications for 30 days after index surgery. RESULTS: There was no statistical difference in baseline characteristics of patients between two groups (p > 0.05). There was a trend that the operative time of RATKA was prolonged compared with manual TKA (p < 0.0001). However, the risks of infection and blood loss did not increase accordingly (p > 0.05). No statistical difference was found in the correction of mechanical alignment between two groups (p > 0.05). The RATKA was associated with reduced pain post-operatively in day 1 (p < 0.05). Afterwards, there was no systematic difference in VAS score from day two to three post-operatively (p > 0.05). There was no significant difference in functional recovery (p > 0.05). No complication occurred in both groups. CONCLUSION: Although the operative time was prolonged in RATKA, it did not increase the risks of infection and blood loss. There was no significant difference in radiological or functional outcomes between RATKA and conventional manual TKA. RATKA might be related to reduced pain after surgery.

The effect of BMI on the mid-term clinical outcomes of mobile-bearing unicompartmental knee arthroplasty.

OBJECTIVE: To evaluate the impact of body mass index (BMI) on the mid-term clinical outcomes and survival in patients receiving a mobile-bearing unicompartmental knee arthroplasty (UKA). METHODS: We retrospectively collected data from 355 patients who underwent UKA from June 2006 to June 2015, with a mean follow-up of 106.5 ± 22.5 months. Patients were assigned into four groups based on their BMI before surgery: normal weight group (BMI 18.5 ~ 22.9 kg/m2), overweight group (23 ~ 24.9 kg/m2), obesity group (25 ~ 29.9 kg/m2), and severe obesity group (≥ 30 kg/m2). The knee society score (KSS), knee society function score (KSFS), hospital for special surgery score (HSS), and range of motion (ROM) were assessed before the operation and at the last follow-up. The femorotibial angle (FTA) was assessed after the operation immediately and at the last follow-up. Kaplan-Meier survival analysis was performed among the four groups. RESULTS: The KSS, KSFS, and HSS in all groups were markedly improved compared with the preoperative values (p<0.001), but the ROM score was not significantly different (p>0.05). There were significant differences in KSS (p<0.001) and HSS (p = 0.004) across the four BMI groups, and these differences were due to the severe obesity group. All groups exhibited an inclination of knee varus deformity at the last follow-up (p < 0.05). Moreover, no marked difference in the implant survival rate was found among the different groups (p = 0.248), or in the survival curves (p = 0.593). CONCLUSIONS: BMI does not influence the implant survival rate. The postoperative functional and quality-of-life scores were significantly improved in all groups. Obese (BMI ≥30 kg/m2) individuals should not be excluded from UKA.

Accuracies of bone resection, implant position, and limb alignment in robotic-arm-assisted total knee arthroplasty: a prospective single-centre study.

OBJECTIVE: This study assessed the accuracy of robotic-arm-assisted total knee arthroplasty (RATKA) for bone resection, component size prediction, implant placement, and limb alignment. METHODS: This prospective cohort study included 36 patients. All procedures were performed by a single experienced surgeon, using an identical approach and implant designs. The MAKO RIO Robotic Interactive Orthopaedic Arm (Stryker, Mahwah, NJ, USA) system was used. The actual bone resection, implant placement, component size, and postoperative mechanical alignment were recorded, then compared with the preoperative plan. RESULTS: The mean absolute differences from the plan for the distal (medial and lateral) and posterior (medial and lateral) femoral cuts were 0.39 mm (0.62), 0.49 mm (0.70), 0.62 mm (0.79), and 0.65 mm (0.81), respectively, with 0.57° (0.65) varus. The mean absolute differences in the medial and lateral tibial cuts were 0.56 mm (0.75) and 0.58 mm (0.76), with 0.48° (0.16) varus and 0.54° (0.25) anterior/posterior slope. Of 192 bone resections, 176 (91.7%) were within ≤ 1 mm of the preoperative plan. The accuracies of femoral and tibial component size prediction were 100% and 97.22%, respectively. The mean absolute difference in final limb coronal alignment was 0.92° (0.65). Of the alignments, 18 (75.0%) were within ≤ 1.00° of the plan, and 100% were within ≤ 3.00° of the plan. CONCLUSION: RATKA could accurately predict the component size and execute a preoperative plan to achieve precise bone resection, and implant placement, thereby reducing alignment outliers.