Search

Introduction: The rationale for discarding the skin knife blade and replacing it with another blade for deeper dissection is to prevent bacteria that may be present on the skin from being carried into the deeper layers of the wound. This practice is very controversial because numerous, yet limited, studies exist that support and refute the findings. The purpose of this study was to directly compare the rate of contamination of a skin knife blade with a control blade., Methods: We took the surface samples using Replicate Organism Detection and Counting plates of 344 knife blades immediately after making skin incision during the following four types of orthopaedic cases: total hip arthroplasty, total knee arthroplasty, lumbar spine surgery, and cervical spine surgery. At the same time, we sampled 344 control blades. The comparison of positives skin versus control, overall and within each subgroup was done using a bivariate two-sample z-test for the equality of proportions., Results: Overall, 35 (5.1%) of the 688 specimens had a positive result. No difference was noted in the rate of positive cultures for the 344 skin blades 4.9% and the 344 control blades 5.2%. No differences were observed in the rate of positive specimens for skin blades (7.4%, 3.4%, 7.7%, and 3.9%) and control blades (2.5%, 4.1%, 7.7%, and 9.2%) for total hip arthroplasty, total knee arthroplasty, C spine, and L spine, respectively. No differences were observed regarding skin prep, room number, case order, room turnover time, or in-room to incision time. Staphylococus species was the predominant bacteria identified., Conclusion: We found no evidence to support the theoretical advantage of changing the knife blade after making skin incision to avoid contamination. Contamination rates were the same for both the skin and control blades overall and for all subgroup analysis.

Introduction: The purpose of our study is to directly compare the rates of instability after revision total hip arthroplasty (THA) between a modular dual mobility (DM) and a conventional polyethylene single-bearing surface., Methods: We retrospectively reviewed a consecutive series of patients who underwent revision THA from 2012 to 2016 at a single institution with a minimum of 2 years of follow-up. Rates of re-revision, dislocation, complications, and short-form (SF-12) scores were compared between the DM and single-bearing groups. To control for confounding variables, a multivariate logistic regression analysis was performed., Results: Of the 267 revision THA patients, 94 patients had a DM bearing articulation (36%), whereas 173 patients (64%) had a conventional single-bearing with a mean follow-up of 37.8 months (range 24 to 73 months). The DM group was more likely to undergo revision THA for instability compared with the single-bearing group (8.5% versus 1.2%, P ≤ 0.005) but had reduced incidence of postoperative dislocations (2.1% versus 8.7%, P = 0.067) and no difference in the rates of re-revisions (9.6% versus 11.6%, P = 0.770). When controlling for confounding variables, patients who received a DM liner had lower rates of dislocation postoperatively than those of single-bearing (odds ratio 0.12, P = 0.019)., Discussion: Even with a selection bias of surgeons using DM for patients at high risk of instability, patients undergoing revision THA with a DM bearing have reduced rates of dislocation at the intermediate-term follow-up. Further study is needed to identify any potential longer-term complications which may result from a modular DM bearing.

Background: Surgeons frequently obtain intraoperative cultures at the time of revision total joint arthroplasty. The use of broth or liquid medium before applying the sample to the agar medium may be associated with contamination and false-positive cultures; however, the degree to which this is the case is not known., Questions/purposes: We (1) calculated the performance characteristics of broth-only cultures (sensitivity, specificity, positive predictive value, and negative predictive value) and (2) characterized the organisms identified in broth to determine whether a specific organism showed increased proclivity for true-positive periprosthetic joint infection (PJI)., Methods: A single-institution retrospective chart review was performed on 257 revision total joint arthroplasties from 2009 through 2010. One hundred ninety (74%) had cultures for review. All culture results, as well as treatment, if any, were documented and patients were followed for a minimum of 1 year for evidence of PJI. Cultures were measured as either positive from the broth only or broth negative. The true diagnosis of infection was determined by the Musculoskeletal Infection Society criteria during the preoperative workup or postoperatively at 1 year for purposes of calculating the performance characteristics of the broth-only culture., Results: The sensitivity, specificity, positive predictive value, and negative predictive value were 19%, 88%, 13%, and 92%, respectively. The most common organism identified was coagulase-negative Staphylococcus (16 of 24 cases, 67%). Coagulase-negative Staphylococcus was present in all three true-positive cases; however, it was also found in 13 of the false-positive cases., Conclusions: The broth-only positive cultures showed poor sensitivity and positive predictive value but good specificity and negative predictive value. The good specificity indicates that it can help to rule in the presence of PJI; however, the poor sensitivity makes broth-only culture an unreliable screening test. We recommend that broth-only culture results be carefully scrutinized and decisions on the diagnosis and treatment of infection should be based specifically on the Musculoskeletal Infection Society criteria., Level of Evidence: Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.

In recent years, there has been an apparent increase in the incidence of pulmonary embolus after joint arthroplasty at our institution. We hypothesized the use of sophisticated imaging modalities such as the multidetector computed tomography scan, with better sensitivity, resulted in an apparent increase in the incidence of pulmonary embolus. We studied all patients with pulmonary embolus after joint arthroplasty between 2000 and 2005. The incidence of pulmonary embolus increased from 0.21% (six of 2859) when VQ scan was the modality of choice to 0.98% (50 of 5095) during the time spiral computed tomography was used to 1.72% (89 of 5179) in recent years when multidetector computed tomography was used. Despite the apparent increase in pulmonary embolus, we observed no change in mortality during the study period. Surgeons should be aware of the challenges sophisticated imaging modalities in general and modern imaging introduce for pulmonary embolus in particular. Extremely sensitive imaging tests with unknown specificity have resulted in an increase in diagnosed pulmonary embolus. However, diagnosing pulmonary embolus generates implications for further treatment such as prolonged anticoagulation and/or inferior vena cava filter insertion with potential for catastrophic complications. The challenge is to distinguish which require treatment and which do not.

Purpose: Imidazoquinolines (Toll-like receptor-7 agonists) are a class of synthetic immune modulating agents. Imiquimod, a member of this drug family, is currently used as first line topical therapy for genital condyloma. It recently showed clinical efficacy against several benign and malignant skin lesions, including actinic keratosis and basal cell carcinoma. Working primarily through the stimulation of a proinflammatory immune response, the mechanism of action of imiquimod may be similar to that through which bacillus Calmette-Guerin is thought to act. We hypothesized that imidazoquinolines have therapeutic potential against bladder cancer. We determined the in vitro and in vivo effects of imidazoquinolines against bladder cancer cells., Materials and Methods: The human and murine J82, T24, TCC-SUP (American Tissue Culture Collection, Manassas, Virginia) and MBT-2 bladder cancer cell lines were cultured in normal culture medium or medium supplemented with imidazoquinoline. Effects on cell viability, apoptosis induction and cytokine production were evaluated. In addition, the effects of imidazoquinoline on in vivo bladder tumor growth were determined via intravesical instillation in an orthotopic bladder tumor model in the mouse., Results: A dose dependent decrease in cell viability was observed in all tumor cell lines treated with imidazoquinoline. In addition, imidazoquinoline significantly induced apoptosis and cytokine production. In in vivo experiments most mice treated with imidazoquinoline showed only an intense inflammatory response with no evidence of tumor, while control mice showed tumor growth., Conclusions: Imidazoquinolines have potent direct activity against bladder cancer cells by decreasing cell viability and inducing apoptosis and cytokine production. In addition, in vivo data suggest antitumor effects in an orthotopic bladder cancer mouse model. Therefore, imidazoquinolines may have therapeutic potential as a synthetic intravesical agent against bladder cancer.