Diagnosis of periprosthetic joint infections in patients who have rheumatoid arthritis.

Aims: To investigate the optimal thresholds and diagnostic efficacy of commonly used serological and synovial fluid detection indexes for diagnosing periprosthetic joint infection (PJI) in patients who have rheumatoid arthritis (RA). Methods: The data from 348 patients who had RA or osteoarthritis (OA) and had previously undergone a total knee (TKA) and/or a total hip arthroplasty (THA) (including RA-PJI: 60 cases, RA-non-PJI: 80 cases; OA-PJI: 104 cases, OA-non-PJI: 104 cases) were retrospectively analyzed. A receiver operating characteristic curve was used to determine the optimal thresholds of the CRP, ESR, synovial fluid white blood cell count (WBC), and polymorphonuclear neutrophil percentage (PMN%) for diagnosing RA-PJI and OA-PJI. The diagnostic efficacy was evaluated by comparing the area under the curve (AUC) of each index and applying the results of the combined index diagnostic test. Results: For PJI prediction, the results of serological and synovial fluid indexes were different between the RA-PJI and OA-PJI groups. The optimal cutoff value of CRP for diagnosing RA-PJI was 12.5 mg/l, ESR was 39 mm/hour, synovial fluid WBC was 3,654/µl, and PMN% was 65.9%; and those of OA-PJI were 8.2 mg/l, 31 mm/hour, 2,673/µl, and 62.0%, respectively. In the RA-PJI group, the specificity (94.4%), positive predictive value (97.1%), and AUC (0.916) of synovial fluid WBC were higher than those of the other indexes. The optimal cutoff values of synovial fluid WBC and PMN% for diagnosing RA-PJI after THA were significantly higher than those of TKA. The specificity and positive predictive value of the combined index were 100%. Conclusion: Serum inflammatory and synovial fluid indexes can be used for diagnosing RA-PJI, for which synovial fluid WBC is the best detection index. Combining multiple detection indexes can provide a reference basis for the early and accurate diagnosis of RA-PJI.

Intraoperative Direct Sonication of Implants and Soft Tissue for the Diagnosis of Periprosthetic Joint Infection.

BACKGROUND: Sonication is very efficacious for the microbiological diagnosis of periprosthetic joint infection (PJI), but it involves many steps and multiple workplaces and personnel and therefore carries a potential contamination risk. We present an innovative version of the sonication culture method that involves direct sonication of the retrieved implant and soft tissue, without a sonication tube, intraoperatively and incubation using a BACT/ALERT 3D blood culture system to enhance the efficacy of microbiological diagnosis of PJI. METHODS: We performed a prospective study of consecutive patients requiring implant removal and classified them as having PJI or aseptic failure according to standard criteria. The removed prosthetic components and adjacent soft tissue were directly sonicated in a small metal container, without a sonication tube, during the operation. The sonication fluid was immediately incubated in blood culture bottles in the operating room and cultured in the BACT/ALERT 3D blood culture system. The synovial fluid was also cultured in the BACT/ALERT 3D system to serve as a comparison. RESULTS: Of the 64 included patients, 36 had PJI and 28 had aseptic failure. Fluid from direct sonication and conventional synovial fluid showed sensitivities of 91.7% and 55.6% (p < 0.001) and specificities of 82.1% and 92.9%, respectively. Fourteen cases of PJI were detected by culture of fluid from direct sonication but not by culture of synovial fluid. Higher sensitivity was obtained by direct sonication of only tissue than by direct sonication of only the implant (88.9% versus 75.0%). No significant difference in detection time was found between Staphylococcus aureus and coagulase-negative Staphylococcus. CONCLUSIONS: When combined with incubation in BACT/ALERT bottles, direct intraoperative sonication of implants and soft tissues without a sonication tube was more sensitive than conventional synovial fluid culture and could reliably and rapidly detect the bacteria commonly found in PJI. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Satisfaction of Patients with Above-the-knee Amputation following Periprosthetic Joint Infection / 中山大学学报(医学科学版)

ObjectiveThe purpose of this study was to evaluate the functional outcomes and satisfaction in periprosthetic knee infection patients after above-the-knee amputation （AKA）. MethodsA review was performed in 13 patients who underwent AKA due to periprosthetic knee infection from October 2010 to August 2022， there were 7 females and 6 males with the median age of 69 （45~ 73） years. The mean number of surgical procedures between primary total knee arthroplasty and AKA was 2.9 times （range： 1 ~ 6）. Patients were segregated into non-elderly group （including patients <65 years old） and elderly group （involving patients ≥65 years old）. Functional outcomes were evaluated by SF-12 and Barthel activities daily living index （Barthel ADL index）. Patient satisfaction was accomplished through a questionnaire. ResultsFour patients died within 6 months after the amputation. Three patients received surgical procedures for recurrent infections after AKA. In the remaining 9 patients，the median time from AKA to the final follow-up was 4.2 （1.9~8.2） years， three patients received surgical procedures for recurrent infections after AKA. Patients in non-elderly group showed better functional outcomes than elderly patients after AKA （both P<0.05）. All patients in non-elderly group were fitted with a prosthesis. Whereas， elderly patients reported a better satisfaction after AKA than young patients. ConclusionYoung PJI patients seemed to have better function and ambulatory ability with high expectation and demand， which made them feel less satisfied about AKA. Meanwhile，despite poor function outcomes due to the less healthy physical condition， the alleviation of financial and psychological burdens resulting from reinfections and multiple surgeries and the less demand in function and daily activities made elderly patients have a good satisfaction after AKA.

Low-dose strontium stimulates osteogenesis but high-dose doses cause apoptosis in human adipose-derived stem cells via regulation of the ERK1/2 signaling pathway.

BACKGROUND: Strontium is a widely used anti-osteoporotic agent due to its dual effects on inhibiting bone resorption and stimulating bone formation. Thus, we studied the dose response of strontium on osteo-inductive efficiency in human adipose-derived stem cells (hASCs). METHOD: Qualitative alkaline phosphatase (ALP) staining, quantitative ALP activity, Alizarin Red staining, real-time polymerase chain reaction and Western blot were used to investigate the in vitro effects of a range of strontium concentrations on hASC osteogenesis and associated signaling pathways. RESULTS: In vitro work revealed that strontium (25-500 µM) promoted osteogenic differentiation of hASCs according to ALP activity, extracellular calcium deposition, and expression of osteogenic genes such as runt-related transcription factor 2, ALP, collagen-1, and osteocalcin. However, osteogenic differentiation of hASCs was significantly inhibited with higher doses of strontium (1000-3000 µM). These latter doses of strontium promoted apoptosis, and phosphorylation of ERK1/2 signaling was increased and accompanied by the downregulation of Bcl-2 and increased phosphorylation of BAX. The inhibition of ERK1/2 decreased apoptosis in hASCs. CONCLUSION: Lower concentrations of strontium facilitate osteogenic differentiation of hASCs up to a point; higher doses cause apoptosis of hASCs, with activation of the ERK1/2 signaling pathway contributing to this process.

Treatment of the femoral shaft nonunion with double plate fixation and bone grafting: A case series of 14 patients.

INTRODUCTION: The management of femoral shaft nonunion still remains a challenge in orthopaedic surgery. It represents a serious postoperative problem for the patient, associated with plate breakage and loosening, bone defect, shortening deformity and infection. A double plate fixation combined with bone grafting may become a promising therapeutic strategy for the treatment of patients with femoral shaft nonunion. In this study, our goal was to evaluate the clinical outcome of a novel approach for 14 consecutive patients with femoral shaft nonunion using double plate fixation with bone grafting. METHODS: Retrospective data from June 2010 to August 2012 were obtained from records for 14 consecutive femoral shaft aseptic nonunion patients treated with double plate fixation combined with bone grafting. Nine patients were men and five patients were woman and average age of the patients was 26 years (range from 22 to 32 years). The mean time since injury was 26.2 months. The nonunion had resulted from repeated internal fixation failure (including plate or intramedullary nail fixation) in nine cases and primary internal fixation in five cases. RESULTS: All the 14 patients were followed up for an average of 14.8 (10-25) months. All cases achieved bony union without wound infection or fixation failure and the mean time to union was 5.2 months (range 4-7 months). CONCLUSION: Double plate fixation and bone grafting are a promising method for femoral shaft nonunion. In addition, this strategy is useful for such a nonunion caused by a repeated plate or intramedullary nail fixation failure with bone defect due to its strong stability with three-dimensional fixation and fully bone graft availability.

Association between the PvuII and XbaI polymorphisms in estrogen receptor alpha gene and risk of osteoarthritis：a Meta-analysis / 中国组织工程研究

BACKGROUND:There are a lot of reports about the association between estrogen receptor α polymorphism and osteoarthritis susceptibility, but the results are stil some controversial. OBJECTIVE:To investigate the relationship between the estrogen receptor α gene PvuII, XbaI site polymorphisms and genetic susceptibility of osteoarthritis. METHODS: A computer-based search of PubMed, web of science, Wanfang, CNKI, Weipu and China Biology Medicine Disc was performed for the published case-control studies addressing the association between estrogen receptor α gene PvuII, XbaI site polymorphism and osteoarthritis susceptibility. Odds radio (OR) and 95% confidence interval were used to analyze the correlation between estrogen receptor α gene PvuII, XbaI site polymorphism and osteoarthritis. Fixed or random effect models were selected for pooledOR calculation. Publication bias was assessed. Al statistical analysis was constructed with Revman5.1 software. RESULTS AND CONCLUSION:Nine case-control studies including 3 228 cases of osteoarthritis and 6 327 healthy controls were included. Overal, the pooledOR values of PvuII loci aleles and genotypes (Cvs. T; CTvs. TT; CCvs. TT; CT+CCvs. TT; CCvs. CT+TT) were less than 1; the pooled OR values of Asian which grouped by region were greater than 1 (except CTvs. TT); the pooledOR values of Europe and the Americas were less than 1. The pooledOR values of XbaI loci aleles and genotypes (Gvs.A; GAvs. AA; GGvs. AA; GA+GGvs. AA; GGvs. GA+AA) were less than 1; the pooledOR values of Asian which grouped by region were less than 1; the pooledOR value of Europe and the Americas were less than 1 (except GGvs.GA+AA). Estrogen receptor α gene PvuII, XbaI site polymorphism is not associated with osteoarthritis susceptibility. However, the susceptibility of PvuII loci in the Asian is a little higher compared with that of the Europeans and American population. On the contrary, the susceptibility of XbaI loci in the recessive genetic model of Europeans and American population is a little higher compared with that of the Asian, suggesting a possible role of ethnic differences in genetic backgrounds.