A staged use of tourniquet does not influence the fast-track recovery after total knee arthroplasty: a prospective randomized study.

INTRODUCTION: Upper-tight tourniquet is widely used in Total Knee Arthroplasty in different modalities. However, it has been associated with a negative impact on post-operative muscle strength end pain. This study aimed to investigate the effect of tourniquet on post-operative pain and recovery in enhanced recovery joint surgery. MATERIALS AND METHODS: In this prospective randomized study, we included 116 patients undergoing to TKA. Surgery was performed with a staged use of tourniquet in Group A (58 patients) and without tourniquet in Group B. In the former group a low-pressure tourniquet was deflated after bone cuts to allow hemostasis of posterior recess and re-inflated for cementation. For all patients a multimodal fast-track recovery protocol was used. Time to reach rehabilitation milestones was recorded as primary endpoint. Range of motion, pain, hemarthrosis, total blood loss, surgical field visualization, Knee Score (KS) and Oxford Knee Score (OKS) were considered as secondary outcomes. RESULTS: . No statistically significant differences were found (group B: average 1.3 ± 0.6 day; group A: average 1.2 ± 0.5 day). Group A had a shorter mean surgical time and a clearer surgical field visualization. Group B had a larger estimated blood loss and hemoglobin drop without a statistically significant difference in the transfusion rate. No differences between the groups were seen in the KS, OKS and range of motion (ROM) and post-operative joint swelling. Pain score was similar between cohorts and recorded thigh pain was surprisingly greater in group B. DISCUSSION: The use of tourniquet in TKA surgery helps to minimize intraoperative blood loss and improves surgical field visualization. Its application with a modern and staged protocol does not affect the functional outcomes (OKS, KSS, ROM) of the early post operative period without compromising the fast-track recovery.

A novel quantitative grading system for implant fixation in revision total knee arthroplasty.

Aims: Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis). Methods: Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system. Results: At a mean follow-up of 90 months (64 to 130), only two out of 245 cases failed due to aseptic loosening. Intraoperative grading yielded mean scores of 1.87 (95% confidence interval (CI) 1.82 to 1.92) for the femur and 1.96 (95% CI 1.92 to 2.0) for the tibia. Only 3.7% of femoral and 1.7% of tibial reconstructions fell below the 1.5-point threshold, which included the two cases of aseptic loosening. Interobserver reliability for postoperative radiological grading was 0.97 for the femur and 0.85 for the tibia. Conclusion: A minimum score of 1.5 points for each skeletal segment appears to be a reasonable cut-off to define sufficient fixation in rTKA. There were no revisions for aseptic loosening at mid-term follow-up when this fixation threshold was achieved or exceeded. When assessing first-time revisions, this novel grading system has shown excellent intra- and interobserver reliability.

Epiphyseal fixation in revision total knee arthroplasty: a comparison between trabecular metal and titanium augments.

INTRODUCTION: The purpose of this retrospective study was to compare the medium-term clinical and radiographic outcomes of two series of patients treated for revision TKA: one implanted with trabecular metal (TM) augments and one implanted with classic titanium augments. MATERIALS AND METHODS: A total of 85 patients with a type 2 AORI defect underwent revision TKA and were treated either with TM epiphyseal augments directly screwed in the bone or with traditional titanium augments. There were 46 patients in the TM group and 39 patients in the titanium group included in the study. All the patients received the same varus-valgus constrained implant and no metaphyseal fixation devices were used. RESULTS: After a mean follow-up of 66.4 months, no statistically significant difference was observed in terms of failure for aseptic loosening between the two groups (4% in the TM group and 7.8% in the titanium group, p = 0.35). The ten-year survival using aseptic loosening as endpoint was 90.5% (95% CI 94.1-98.6) in the TM group and 85% (95% CI 101.9-119.3) in the titanium group (p = 0.26). A statistically significant difference was detected for the presence of RLL. No RLL were found under the studied TM augments compared to 13.7% of the titanium augments (p = 0.01). CONCLUSION: The use of TM augments directly screwed to the epiphysis of the femur and the tibia reduced the incidence of RLL compared to standard titanium augments during revision TKA with promising medium-term results.

Barbed sutures and skin adhesives improve wound closure in hip and knee arthroplasty.

PURPOSE: This study aimed to formulate evidence-based recommendations for optimising wound management in hip and knee arthroplasty by exploring alternative methods such as barbed sutures and skin adhesives. METHODS: A Delphi panel, comprising seven orthopaedic surgeons, one musculoskeletal infectious disease specialist, and one health economics expert, was convened to evaluate the use of barbed sutures and skin adhesives for wound closure in hip and knee arthroplasty. Two systematic reviews informed the development of questionnaires, with panelists ranking their agreement on statements using a 5-point Likert scale. Consensus was achieved if ≥75% agreement. Unresolved statements were revisited in a second round. RESULTS: Consensus was reached on 11 statements, providing evidence-based recommendations. The expert panel advocates for a multilayer watertight technique using barbed sutures to prevent surgical site infections (SSI), reduce complications, shorten surgical times, optimise resources and improve cosmetic appearance. For skin closure, the panel recommends topical adhesives to decrease wound dehiscence, enhance cosmetic appearance, promote patient compliance, prevent SSIs, and optimise resources. CONCLUSION: The Delphi consensus by Italian total joint arthroplasty experts underscores the pivotal role of barbed sutures and skin adhesives in optimising outcomes. While guiding clinical decision-making, these recommendations are not prescriptive and should be adapted to local practices. The study encourages further research to enhance current evidence. LEVEL OF EVIDENCE: Level III.

Standardized Fixation Zones and Cone Assessments for Revision Total Knee Arthroplasty Using Deep Learning.

BACKGROUND: Achieving adequate implant fixation is critical to optimize survivorship and postoperative outcomes after revision total knee arthroplasty (rTKA). Three anatomical zones (ie, epiphysis, metaphysis, and diaphysis) have been proposed to assess fixation, but are not well-defined. The purpose of the study was to develop a deep learning workflow capable of automatically delineating rTKA zones and cone placements in a standardized way on postoperative radiographs. METHODS: A total of 235 patients who underwent rTKA were randomly partitioned (6:2:2 training, validation, and testing split), and a U-Net segmentation workflow was developed to delineate rTKA fixation zones and assess revision cone placement on anteroposterior radiographs. Algorithm performance for zone delineation and cone placement were compared against ground truths from a fellowship-trained arthroplasty surgeon using the dice segmentation coefficient and accuracy metrics. RESULTS: On the testing cohort, the algorithm defined zones in 98% of images (8 seconds/image) using anatomical landmarks. The dice segmentation coefficient between the model and surgeon was 0.89 ± 0.08 (interquartile range [IQR]:0.88-0.94) for femoral zones, 0.91 ± 0.08 (IQR: 0.91-0.95) for tibial zones, and 0.90 ± 0.05 (IQR:0.88-0.94) for all zones. Cone identification and zonal cone placement accuracy were 98% and 96%, respectively, for the femur and 96% and 89%, respectively, for the tibia. CONCLUSION: A deep learning algorithm was developed to automatically delineate revision zones and cone placements on postoperative rTKA radiographs in an objective, standardized manner. The performance of the algorithm was validated against a trained surgeon, suggesting that the algorithm demonstrated excellent predictive capabilities in accordance with relevant anatomical landmarks used by arthroplasty surgeons in practice.

Inferior results at long-term follow-up after extensor mechanism allograft reconstruction in septic compared to aseptic revision total knee arthroplasty.

PURPOSE: Extensor mechanism lesion after total knee arthroplasty (TKA) is a catastrophic complication. Reconstruction with extensor mechanism allograft (EMA) has been described as a sound salvage procedure. Its effectiveness at long term and in septic cases is still under scrutiny. The long-term results of EMA reconstruction for chronic extensor mechanism failures following aseptic and septic revision TKA have been analysed. METHODS: From the institutional database, 35 patients with a revision TKA (RevTKA) undergoing EMA reconstruction from 2005 to 2015 have been retrospectively identified. A history of periprosthetic joint infection (PJI) was found in 13 (37%) patients. The mean follow-up was 81.2 months (± 34.7, range 3-120). EMA failures were considered for lag more than 20°, Knee Society Score (KSS) less than 60 points, and/or in the case of revision of the allograft. RESULTS: The mean KSS improved from 35.9 (± 16.9, range 0-54) to 86.6 (± 10.4, range 54-99) points in the aseptic group (p < 0.001) and from 27.5 (± 11.6, range 10-44) to 79.4 (± 16.3, range 48-94) points in the septic group (p < 0.001). The extensor lag changed from 48.4° (± 14.5, range 30-90) to 4.6° (± 10.8, range 0-50) in the aseptic group (p < 0.001) and from 56.5° (± 20.8, range 30-90) to 6.1° (± 6.8, range 0-20) in the septic group (p < 0.001). The mean postoperative flexion was 105.2° (± 13.2, range 75-130) in the aseptic group and 102.7° (± 12.5, range 80-120) in the septic group (p = 0.32). Three failures (14% of the cases) occurred in the aseptic group and five in the septic group (38% of the cases). The overall survivorship at 10 years was 83.3% (22 cases, CI95 94.2-121.7) vs 58% (13 cases, CI95 67.2-111.7) in the aseptic and septic group, respectively (p = 0.01). CONCLUSIONS: EMA reconstruction after extensor mechanism disruptions in TKA is a reliable salvage procedure. The septic nature of the revision decreased the functionality of the knee joint after EMA, but it did not represent a risk factor for re-ruptures or recurrence of infection. LEVEL OF EVIDENCE: Level III.

"Systematic review and meta-analysis of ceramic coated implants in total knee arthroplasty. Comparable mid-term results to uncoated implants."

BACKGROUND: Nitride-based ceramic coatings, such as titanium nitride (TiN) and titanium niobium nitride (TiNbN), have been introduced in total knee arthroplasty (TKA) to enhance the mechanical properties and biocompatibility of knee components, harden the metal surface and reduce CoCrMo exposure and metal ion release. However, the theoretical advantages of these ceramic coatings in TKA have yet to be fully elucidated. This systematic review aimed to provide clinical evidence on mid-term outcomes of ceramic-coated knee prostheses in comparison with uncoated standard CoCrMo knee prostheses in primary TKA. The hypothesis was that ceramic-coated implants can be used in primary TKA with no inferior outcomes compared to uncoated CoCrMo implants. METHODS: A systematic review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to find all clinical studies regarding primary TKA with ceramic-coated knee prostheses. MEDLINE (PubMed), Embase and Cochrane Library were searched from 1990 to October 2020 to identify relevant studies for the first qualitative analysis. Using PICOS eligibility criteria, a subgroup of the selected studies was used to perform a meta-analysis. RESULTS: Fifteen studies were included in this systematic review, of which six were included in the meta-analysis: 3 randomized controlled trials, 2 retrospective comparative studies and 1 prospective cross-sectional study. Pooled data overall included 321 coated TKAs vs. 359 uncoated TKAs and a mean follow-up of 4.6 years (range, 2-10 years). No significant difference in the implant survival risk ratio with revision or reoperation due to any reason was found between coated and uncoated TKAs, even considering the RCT study subgroup with a risk ratio of 1.02 (P = 0.34). No significant differences were found for postoperative complications, clinical scores, or metal blood concentrations at 1 year. CONCLUSION: The findings of this systematic review and meta-analysis support the statement that ceramic-coated TKAs are not inferior to uncoated TKAs, showing comparable survival rates, complication rates and clinical outcomes. There is strong evidence that ceramic-coated TKA does not improve the clinical results or survival rate in comparison with uncoated TKA. LEVEL OF EVIDENCE: II,  Therapeutic.

Extensor mechanism reconstruction with allograft following total knee arthroplasty: a systematic review and meta-analysis of achilles tendon versus extensor mechanism allografts for isolated chronic patellar tendon ruptures.

BACKGROUND: Extensor mechanism rupture is a severe complication with an incidence of 0.1-2.5% after total knee arthroplasty (TKA). Achilles tendon allograft (ATA) and extensor mechanism allograft (EMA) in TKA surgery have yielded mixed clinical results. Our systematic review aims to identify the proportion of failure in extensor mechanism reconstruction after TKA using allograft and evaluate clinical and functional outcomes and the most common complications. Furthermore, we performed a meta-analysis among studies dealing with isolated patellar tendon ruptures to assess the failure rate, surgical complications, and clinical findings (extensor lag and knee range of motion) of extensor mechanism reconstruction using either ATA or EMA grafts. METHODS: A systematic review of the literature was performed following the PRISMA guidelines, including the studies dealing with the use of EMA and ATA for extensor mechanism rupture following TKA. Coleman Methodology Score and the MINORS score were used to assess the quality of the studies. A meta-analysis was performed to evaluate the failure rate, complications, and clinical findings (extensor lag and knee range of motion) of the ATA and EMA treatments in isolated patellar tendon ruptures. RESULTS: A total of 238 patients (245 knees), with a mean age ranging from 54 to 74 years, who underwent extensor mechanism reconstruction with an allograft were identified in the 18 included studies. We analysed 166 patellar tendon ruptures, 29 quadriceps tendon ruptures, and 29 patellar fractures in the analysis. A chronic injury was described in the majority of included cases. ATA and whole EMA were used in 89 patients (92 knees) and 149 patients (153 knees), respectively. The overall failure percentage was 23%, while EMA and ATA were 23 and 24%. The most common complication was extensor lag (≥ 20°). The overall incidence of postoperative infection was 7%. Eleven of 14 included papers reported more than 100° of the mean postoperative knee flexion. The percentage of patients requiring walking aids is 55 and 34.5% in ATA and EMA, respectively. The failure outcome after extensor mechanism reconstruction in isolated patellar tendon ruptures was 27%, with no statistical difference between EMA and ATA in terms of failure rate and clinical outcomes. CONCLUSIONS: Extensor mechanism reconstruction with allograft represents a valid treatment option in patients with acute or chronic rupture following total knee arthroplasty. Persistent extensor lag represents the most common complication. EMA is associated with a lower frequency of patients requiring walking aids at last follow-up, although it has similar clinical and functional outcomes to ATA. In patellar tendon ruptures, ATA has a comparable success rate with EMA. LEVEL OF EVIDENCE: Level IV, therapeutic study. TRIAL REGISTRATION: PROSPERO 2019 CRD42019141574.

New Horizons of Cementless Total Knee Arthroplasty.

BACKGROUND: Considering the increasing number of young and active patients needing TKA, orthopedic surgeons are looking for a long-lasting and physiological bond for the prosthetic implant. Multiple advantages have been associated with cementless fixation including higher preservation of the native bone stock, avoidance of cement debris with subsequent potential third-body wear, and the achievement of a natural bond and osseointegration between the implant and the bone that will provide a durable and stable fixation. DISCUSSION: Innovations in technology and design have helped modern cementless TKA implants to improve dramatically. Better coefficient of friction and reduced Young's modulus mismatch between the implant and host bone have been related to the use of porous metal surfaces. Moreover, biologically active coatings have been used on modern implants such as periapatite and hydroxyapatite. These factors have increased the potential for ingrowth by reducing micromotion and increasing osteoconductive properties. New materials with better biocompatibility, porosity, and roughness have been introduced to increase implant stability. CONCLUSIONS: Innovations in technology and design have helped modern cementless TKA implants improve primary stability in both the femur and tibia. This means that short-term follow-up are comparable to cemented. These positive prognostic factors may lead to a future in which cementless fixation may be considered the gold-standard technique in young and active patients.

Blood Analytes as Biomarkers of Mechanisms Involved in Alzheimer's Disease Progression.

Alzheimer's disease (AD) is the leading cause of dementia, but the pathogenetic factors are not yet well known, and the relationships between brain and systemic biochemical derangements and disease onset and progression are unclear. We aim to focus on blood biomarkers for an accurate prognosis of the disease. We used a dataset characterized by longitudinal findings collected over the past 10 years from 90 AD patients. The dataset included 277 observations (both clinical and biochemical ones, encompassing blood analytes encompassing routine profiles for different organs, together with immunoinflammatory and oxidative markers). Subjects were grouped into four severity classes according to the Clinical Dementia Rating (CDR) Scale: mild (CDR = 0.5 and CDR = 1), moderate (CDR = 2), severe (CDR = 3) and very severe (CDR = 4 and CDR = 5). Statistical models were used for the identification of potential blood markers of AD progression. Moreover, we employed the Pathfinder tool of the Reactome database to investigate the biological pathways in which the analytes of interest could be involved. Statistical results reveal an inverse significant relation between four analytes (high-density cholesterol, total cholesterol, iron and ferritin) with AD severity. In addition, the Reactome database suggests that such analytes could be involved in pathways that are altered in AD progression. Indeed, the identified blood markers include molecules that reflect the heterogeneous pathogenetic mechanisms of AD. The combination of such blood analytes might be an early indicator of AD progression and constitute useful therapeutic targets.

Synovial fluid alpha-defensin in periprosthetic knee infection workup : liquid chromatography-mass spectrometry detection of alpha-defensin in synovial fluid.

AIMS: The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid. METHODS: Between October 2017 and September 2019, we collected synovial fluid samples from patients scheduled to undergo revision surgery for painful total knee arthroplasty (TKA). The International Consensus Meeting criteria were used to classify 33 PJIs and 92 aseptic joints. LC-MS assay was performed to measure alpha-defensin in synovial fluid of all included patients. Sensitivity, specificity, positive predictive value, negative predictive value, and the area under the receiver operating characteristic curve (AUC) were calculated to define the test diagnostic accuracy. RESULTS: The AUC was 0.99 (95% confidence interval (CI) 0.98 to 1.00). Receiver operating characteristic (ROC) analysis showed that the optimal cut-off value of synovial fluid alpha-defensin was 1.0 µg/l. The sensitivity of alpha-defensin was 100% (95% CI 96 to 100), the specificity was 97% (95% CI 90 to 98), the positive predictive value was 89.2% (95% CI 82 to 94), and negative predictive value was 100% (95% CI 96 to 100). ROC analysis demonstrated an AUC of 0.99 (95% CI 0.98 to 1.0). CONCLUSION: The present study confirms the utility of alpha-defensin in the synovial fluid in patients with painful TKA to select cases of PJI. Since LC-MS is still a time-consuming technology and is available in highly specialized laboratories, further translational research studies are needed to take this evidence into routine procedures and promote a new diagnostic approach.Cite this article: Bone Joint J 2022;104-B(9):1047-1051.

Modeling subjective fear using skin conductance: a preliminary study in virtual reality.

Reliably measuring fear perception could help evaluate the effectiveness of treatments for pathological conditions such as specific phobias or post-traumatic stress syndrome (e.g., exposure therapy). In this study, we developed a novel vir-tual reality (VR) scenario to induce fear and evaluate the related physiological response by the analysis of skin conductance (SC) signal. Eighteen subjects voluntarily experienced the fear VR scenario while their SC was recorded. After the experiment, each participant was asked to score the perceived subjective fear using a Likert scale from 1 to 10. We used the cvxEDA algorithm to process the collected SC signals and extract several features able to estimate the autonomic response to the fearful stimuli. Finally, the extracted features were linearly combined to model the subjective fear perception scores by means of LASSO linear regression. The sparsification imposed by the LASSO procedure to mitigate the overfitting risk identified an optimal linear model including only the standard deviation of the tonic SC component as a regressor (p = 0.007; R2 = 0.3337). The significant contribution of this feature to the model suggests that subjects experiencing more intense subjective fear have a more variable and unstable sympathetic tone.

Revision knee surgery: the practical approach.

Revision total knee arthroplasty (rTKA) is a challenging procedure with often unreproducible results. A step-by-step approach is fundamental to achieving good outcomes.Successful surgery requires a correct diagnosis of the original cause of failure. Only with an accurate and detailed plan can surgeons overcome difficulties presented in this scenario.Any bone loss should be prevented during prosthetic component removal. Efficient tools must be chosen to avoid time-consuming manoeuvres.Joint reconstruction based on a 'dual-zone' fixation is essential to provide a long-term survivorship of the implant. The use of relatively short fully cemented stems combined with a biological metaphyseal fixation is highly recommended by authors.Flexion and extension gaps are accurately balanced after the establishment of the tibial platform.Varus-valgus laxity is commonly managed with a condylar constrained prosthesis. If hinged implants are required, a stronger implant fixation is needed to counteract constraints forces. Cite this article: EFORT Open Rev 2021;6:495-500. DOI: 10.1302/2058-5241.6.210018.

Synovial Cell Count Before Reimplantation Can Predict the Outcome of Patients with Periprosthetic Knee Infections Undergoing Two-stage Exchange.

BACKGROUND: Although synovial fluid can be used to diagnose periprosthetic joint infections (PJI) effectively, only the cutoff values adopted at the time of PJI diagnosis have been standardized, and few data are currently available about effectiveness of synovial fluid examination before definitive reimplantation. QUESTIONS/PURPOSES: We asked: (1) What are the most appropriate thresholds for synovial fluid leukocyte counts (WBC) and neutrophil percentage (PMN percentage) in a patient group undergoing definitive reimplantation after an uninterrupted course of antibiotic therapy for chronic PJI? (2) What is the predictive value of our synovial WBC and PMN percentage threshold compared with previously proposed thresholds? METHODS: In all, 101 patients with PJI were evaluated for inclusion from January 2016 to December 2018. Nineteen percent (19 of 101) of patients were excluded because of the presence of a chronic inflammatory disease, acute/late hematogenous infection, low amount of synovial fluid for laboratory investigations or infection persistence after spacer placement, and adequate antibiotic therapy. Finally, 81% (82 of 101) of patients with a median (range) age of 74 years (48 to 92) undergoing two-stage revision for chronic TKA infection, who were followed up at our institution for a period 96 weeks or more, were included in this study. The patients did not discontinue antibiotic treatment before reimplantation and were treated for 15 days after reimplantation if intraoperative cultures were negative. No patient remained on suppressive treatment after reimplantation. Synovial fluid was aspirated aseptically with a knee spacer in place to evaluate the cell counts before reimplantation. Thirteen percent (11 of 82) of patients had persistent or recurrent infection, defined as continually elevated erythrocyte sedimentation rate or C-reactive protein levels coupled with local signs and symptoms or positive cultures. The synovial fluid WBC counts and PMN percentage from the 11 patients with persistent or recurrent PJI were compared with the 71 patients who were believed to be free of PJI. Receiver operating characteristic (ROC) curve analyses assessed the predictive value of the parameters, and the areas under the curves (AUCs) were evaluated. The sensitivities, specificities, and positive and negative predictive values were determined for the WBC count and PMN percentage. Patients with persistent or recurrent infection had higher median WBC counts (471 cells/µL versus 1344 cells/µL; p < 0.001) and PMN percentage (36% versus 61%; p < 0.001) than did patients believed to be free of PJI. RESULTS: ROC curve analysis identified the best threshold values to be a WBC count of 934 cells/µL or more (sensitivity 0.82 [95% CI 0.71 to 0.89], specificity 0.82 [95% CI 0.71 to 0.89]) as well as a PMN percentage of at least 52% (sensitivity 0.82 [95% CI 0.71 to 0.89] and specificity 0.78 [95% CI 0.67 to 0.86]. We found no difference between the AUCs for the WBC count and the PMN percentage (0.87 [95% CI 0.79 to 0.96] versus 0.84 [95% CI 0.73 to 0.95]. Comparing the sensitivities and specificities of the synovial fluid WBC count and PMN percentage proposed by other authors, we find that a PMN percentage more than 52% showed better predictive value than previously reported. CONCLUSION: Based on our findings, we believe that patients with WBC counts of at least 934 and PMN percentage of 52% or more should not undergo reimplantation but rather a repeat debridement, as their risk of persistent or recurrent PJI appears prohibitively high. The accuracy of the proposed cutoffs is better than previously reported. LEVEL OF EVIDENCE: Level III, diagnostic study.

The role of D-dimer in periprosthetic joint infection: a systematic review and meta-analysis.

OBJECTIVES: The current literature on diagnosis of periprosthetic joint infection (PJI) provides controversial evidence on the diagnostic accuracy of D-dimer. Therefore, this critical literature search and meta-analysis was aimed to summarize the diagnostic accuracy of D-dimer for diagnosing PJI. CONTENT: We searched MEDLINE, Scopus, and Web of Science, for studies on D-dimer for diagnosing PJI, according to the PRISMA flowchart. QUADAS was used for assessing study quality. Sensitivity, specificity, positive (PLR) and negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were analyzed using bivariate diagnostic random-effects model. The area under the receiver-operating curve (AUC-ROC) was calculated. Subgroup analysis and univariate meta-regression were carried out for detecting potential sources of heterogeneity. SUMMARY: We included 12 articles, totaling 1,818 patients (539 with PJI). The pooled sensitivity and specificity of D-dimer for diagnosing PJI were 0.739 (95% CI: 0.616-0.833) and 0.785 (95% CI: 0.679-0.863). The pooled PLR, NLR, DOR were 3.359 (95% CI, 2.340-4.821), 0.295 (95% CI, 0.180-0.484), and 11.787 (95% CI, 5.785-24.018). The cumulative ROC plot displayed an AUC of 0.688 (95% CI, 0.663-0.713; p<0.001). No threshold effects could be observed. The type of blood sample was identified as possible source of heterogeneity for DOR (p=0.01). OUTLOOK: Evidence emerged from this meta-analysis suggests that D-dimer displays sufficient diagnostic accuracy to rule out PJI. The type of blood sample (plasma vs. serum) and the study design could influence the results in terms of DOR and sensitivity. However, further perspective studies would be needed to validate its potential diagnostic usefulness.

Laboratory-based versus qualitative assessment of α-defensin in periprosthetic hip and knee infections: a systematic review and meta-analysis.

INTRODUCTION: Two methods are currently available for the assay of α-defensin: the enzyme-linked immunosorbent assay (ELISA) and the lateral flow test. We aimed to assess the diagnostic accuracy of synovial fluid α-defensin and to compare the accuracy of the laboratory-based test and the qualitative assessment for the diagnosis of hip and knee prosthetic infection. MATERIALS AND METHODS: We searched (from inception to May 2018) MEDLINE, Scopus, EMBASE, Web of Science, and Cochrane for studies on α-defensin in the diagnosis of periprosthetic joint infection (PJI). Sensitivity, specificity, positive and negative likelihood ratio (LR), and diagnostic odds ratio were analyzed using the bivariate diagnostic random-effects model. The receiver-operating curve for each method was calculated. RESULTS: We included 13 articles in our meta-analysis, including 1170 patients who underwent total hip and knee arthroplasties revision; 368 (31%) had a joint infection according to MSIS and MSIS-modified criteria. Considering the false-positive result rate of 8% and false-negative result rate of 3%, pooled sensitivity and specificity were 0.90 (95% CI 0.83-0.94) and 0.95 (0.92-0.96), respectively. The area under the curve (AUC) was 0.94 (0.92-0.94). No statistical differences in terms of sensitivity and specificity were found between the laboratory-based and qualitative test. The pooled sensitivity and specificity of the two alpha-defensin assessment methods were: laboratory-based test 0.97 (95% CI 0.93-0.99) and 0.96 (95% CI 0.94-0.98), respectively; qualitative test 0.83 (95% CI 0.73-0.91) and 0.94 (95% CI 0.89-0.97), respectively. The diagnostic odds ratio of the α-defensin laboratory based was superior to that of the qualitative test (1126.085, 95% CI 352.172-3600.702 versus 100.9, 95% CI 30.1-338.41; p < 0.001). The AUC for immunoassay and qualitative tests was 0.97 (0.95-0.99) and 0.91 (0.88-0.99), respectively. CONCLUSION: Detection of α-defensin is an accurate test for diagnosis of hip and knee prosthetic infections. The diagnostic accuracy of the two alpha-defensin assessment methods is comparable. The lateral flow assay is a valid, rapid, and more available diagnostic tool, particularly to rule out PJI.

Bilateral Extensor Mechanism Allograft Reconstruction for Chronic Spontaneous Rupture: A Case Report and Review of the Literature.

CASE: A 51-year-old woman, affected by end-stage renal disease, presented with 16-month-old ruptures of the right patellar tendon and the left quadriceps tendon. Since she had been nonambulatory for more than a year, the authors decided to perform a bilateral one-staged reconstruction with an Achilles tendon allograft on the right side and a full extensor mechanism allograft on the left side, achieving excellent clinical and functional results at 57 months' follow-up. CONCLUSIONS: Bilateral spontaneous rupture of the extensor mechanism of the knee is a rare but dramatic occurrence. Allograft can be considered as a treatment option in case of chronic lesion or delayed reconstruction, with satisfactory midterm outcomes.

Continuous Antibiotic Therapy Can Reduce Recurrence of Prosthetic Joint Infection in Patients Undergoing 2-Stage Exchange.

BACKGROUND: Reimplantation microbiology and serum C-reactive protein have low diagnostic accuracy in predicting recurrence in patients with prosthetic joint infection (PJI) undergoing 2-stage exchange. We aimed at identifying factors relating to failure and comparing effect of continuous antibiotic therapy versus a holiday antibiotic period pre-reimplantation. METHODS: This observational study included patients with PJI undergoing 2-stage exchange. Group A patients did not discontinue antibiotic treatment pre-reimplantation; in group B patients, antibiotic treatment was followed with 2 weeks of holiday antibiotic period pre-reimplantation. We defined cure as absence of recurrence for 96 weeks post-reimplantation. Statistical analyses were performed using Mann-Whitney U test, Fisher exact test, and multivariate analysis. RESULTS: We evaluated 196 patients with PJI (median age, 66 years [interquartile range, 59-72], 91 [46%] males). Comorbidity was reported in 77 (39%), and microbiologic evidence was obtained in 164 (84%). Staphylococcus aureus was isolated in 63 of 164 (38%) patients; coagulase-negative staphylococci were isolated in 71 of 164 (43%). Favorable outcome was achieved for 169 (86%) patients (91% and 79% in groups A and B, respectively). No immunocompromise (odds ratio [OR], 2.73; 95% confidence interval [CI], 1.3-7.3; P = .04), a positive culture (OR, 3.96; 95% CI, 1.55-10.19; P = .02), and no antibiotic discontinuation (OR, 3.32; 95% CI, 1.3-8.44; P = .02) predicted favorable outcome using multivariate analysis. CONCLUSION: Treatment with continuous antibiotic therapy ameliorated success rate, permitting a better outcome in immunocompromised and reducing the time to reimplantation. Continuous antibiotic therapy can be considered a valid option for the treatment of patients with PJI undergoing 2-stage exchange. LEVEL OF EVIDENCE: Therapeutic level II.