PurposeThe prevalence of periprosthetic joint infection (PJI) has increased with the increasing incidence of arthroplasty surgery. Considering identification of causative microorganisms is crucial for treatment of PJI, culture-negative (CN) PJI is a significant clinical issue. The purpose of the present study is to describe epidemiology, diagnosis and treatment of CN PJI based on review of the literature to help prevent delayed diagnosis and improve clinical outcomes of CN PJI.MethodsMEDLINE, EMBASE, Cochrane Library and Scopus databases were searched for articles on CN PJI. Only clinical studies written in English were included. Basic science studies, letters to the editor, case reports and review articles on PJI were excluded.ResultsSeven studies were included in this study. The prevalence of CN PJI ranged from 0% to 42.1%. The major risk factors for CN PJI were prior antibiotic use and presence of postoperative wound drainage. Vancomycin and cephalosporins were the most commonly used antibiotics for CN PJI. Two-stage revision arthroplasty followed by 6 weeks of antibiotic therapy produced the most successful treatment outcomes.ConclusionsIn most clinical studies on CN PJI, a definite diagnostic method for identifying causative microorganisms or optimal treatment strategy for CN PJI were not clearly described. Therefore, further studies are needed to establish standard diagnostic methods for identifying infecting organisms and treatment strategies for CN PJI.
BackgroundThe clinical and radiological outcomes of revision total knee arthroplasty with a cemented posterior stabilized (PS), condylar constrained knee (CCK) or a fully constrained rotating hinge knee (RHK) prosthesis were evaluated.MethodsThis study reviewed the clinical and radiological results of 36 revision total knee arthroplasties with a cemented PS, CCK, and RHK prosthesis in 8, 25, and 13 cases, respectively, performed between 1998 and 2006. The mean follow-up period was 30 months (range, 24 to 100 months). The reason for the revision was aseptic loosening of one or both components in 15, an infected total knee in 18 and a periprosthetic fracture in 3 knees. The average age of the patients at the time of the revision was 65 years (range, 58 to 83 years). The original diagnosis for all primary total knee arthroplasties was osteoarthritis except for one case of a Charcot joint. All revision prostheses were fixed with cement. The bone deficiencies were grafted with a cancellous allograft in the contained defect and cortical allograft fixed with a plate and screws in the noncontained defect. A medial gastrocnemius flap was needed to cover the wound dehiscence in 6 of the 18 infected cases.ResultsThe mean Knee Society knee score improved from 28 (range, 5 to 43) to 83 (range, 55 to 94), (p < 0.001) and the mean Knee Society function score improved from 42 (range, 10 to 66) to 82 (range, 60 to 95), (p < 0.001) at the final follow-up. Good or excellent outcomes were obtained in 82% of knees. There were 5 complications (an extensor mechanism rupture in 3 and recurrence of infection in 2 cases). Three cases of an extensor mechanism defect (two ruptures of ligamentum patellae and one patellectomy) were managed by the RHK prosthesis to provide locking stability in the heel strike and push off phases, and two cases of recurrent infection used an antibiotic impregnated cement spacer. The radiological tibiofemoral alignment improved from 1.7° varus to 3.0° valgus in average. Radiolucent lines were observed in 18% of the knees without progressive osteolysis.ConclusionsRevision total knee requires a more constrained prosthesis than primary total knee arthroplasty because of the ligamentous instability and bony defect. This short to midterm follow-up analysis demonstrated that a well planned and precisely executed revision can reduce pain and improve the knee function significantly. Infected cases showed as good a result as those with aseptic loosening through the use of antibiotics-impregnated cement beads and proper soft tissue coverage with a medial gastrocnemius flap.
Mesenchymal stromal/stem cells (MSCs) demonstrate immunomodulation capacity that has been implicated in the reduction of graft-versus-host disease. Accordingly, we herein investigated the capacity of MSCs derived from several tissue sources to modulate both proinflammatory (interferon [IFN] γ and tumor necrosis factor [TNF] α) and immunosuppressive cytokines (transforming growth factor [TGF] β and interleukin [IL] 10) employing xenogeneic human MSC-mixed lymphocyte reaction (MLR) test. Bone marrow-derived MSCs showed higher self-renewal capacity with relatively slow proliferation rate in contrast to adipose-derived MSCs which displayed higher proliferation rate. Except for the lipoprotein gene, there were no marked changes in osteogenesis- and adipogenesis-related genes following in vitro differentiation; however, the histological marker analysis revealed that adipose MSCs could be differentiated into both adipose and bone tissue. TGFβ and IL10 were detected in adipose MSCs and bone marrow MSCs, respectively. However, skin-derived MSCs expressed both IFNγ and IL10, which may render them sensitive to immunomodulation. The xenogeneic human MLR test revealed that MSCs had a partial immunomodulation capacity, as proliferation of activated and resting peripheral blood mononuclear cells was not affected, but this did not differ among MSC sources. MSCs were not tumorigenic when introduced into immunodeficient mice. We concluded that the characteristics of MSCs are tissue source-dependent and their in vivo application requires more in-depth investigation regarding their precise immunomodulation capacities.
Ossification of the posterior longitudinal ligament (OPLL) can be defined as an ectopic ossification in the tissues of spinal ligament showing a hyperostotic condition. OPLL is developed mostly in the cervical spine and clinical presentations of OPLL are majorly myelopathy and/or radiculopathy, with serious neurological pathology resulting in paralysis of extremities and disturbances of motility lowering the quality of life. OPLL is known to be an idiopathic and multifactorial disease, which genetic factors and non-genetic factors including diet, obesity, physical strain on the posterior longitudinal ligament, age, and diabetes mellitus, are involved into the pathogenesis. Up to now, surgical management by decompressing the spinal cord is regarded as standard treatment for OPLL, although there might be the risk of development of reprogression of ossification. The molecular pathogenesis and efficient therapeutic strategy, especially pharmacotherapy and/or preventive intervention, of OPLL has not been clearly elucidated and suggested. Therefore, in this review, we tried to give an overview to the present research results on OPLL, in order to shed light on the potential pharmacotherapy based on molecular pathophysiologic aspect of OPLL, especially on the genetic/genomic factors involved into the etiology of OPLL.
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