Symptom duration is associated with failure of periprosthetic joint infection treated with debridement, antibiotics and implant retention.

Background: Debridement, antibiotics, and implant retention (DAIR) is an alternative treatment strategy for periprosthetic joint infection (PJI). However, no consensus exists regarding which patient population(s) may be most suitable for DAIR. This study aims to investigate the overall infection control rate and explore the prognostic factors associated with acute, hematogenous, and chronic PJIs treated with DAIR. Methods: We retrospectively reviewed the included patients who were diagnosed with PJI and underwent DAIR at two institutions from 2009 to 2018 (n = 104). We collected the clinical data, including demographics, preoperative laboratory tests, Charlson Comorbidity Index, surgical information, and culture organism results. Treatment success was defined according to the criteria reported by Diaz-Ledezma. All patients were followed for at least one year unless failure preceded that time point. A multivariable analysis was utilized to identify prognostic factors associated with treatment, and a Kaplan-Meier survival analysis was used to depict the infection control rate. Results: The overall treatment success rate in the current cohort of patients was 67.3% at a median 38.6 (interquartile range: 23.5, 90.7) months follow-up. Patients with a duration of infectious symptoms of more than ten days were more likely to fail (P = 0.035, hazard ratio 8.492, 95% confidence interval 1.159-62.212). There was no difference among acute, hematogenous, and chronic infections in terms of failure rate (P = 0.161). Conclusions: DAIR is a reasonable treatment option for PJI, and its use in the setting of chronic infection does not appear to be a contraindication. Performing DAIR within ten days of the presentation of symptoms had a higher rate of treatment success.

The relationship of C-reactive protein/interleukin-6 concentrations between serum and synovial fluid in the diagnosis of periprosthetic joint infection.

BACKGROUND: The relationship of C-reactive protein (CRP)/interleukin-6 (IL-6) concentrations between serum and synovial fluid and whether synovial CRP/IL-6 testing in addition to serum CRP/IL-6 testing would result in a benefit in the diagnosis of periprosthetic joint infection (PJI) deserves to be investigated. METHODS: From June 2016 to July 2019, 139 patients were included in the study. Synovial CRP and IL-6 were tested by ELISA. The serum CRP and IL-6 were obtained from medical records. The definition of PJI was based on the modified Musculoskeletal Infection Society (MSIS) criteria. The relationship of serum and synovial CRP and IL-6 and the value of each index in the diagnosis of PJI were evaluated. RESULTS: The receiver operating characteristic (ROC) curves showed that synovial IL-6 had the highest area under the curve (AUC) at 0.935, which was followed by synovial CRP, serum IL-6 and serum CRP 0.861, 0.847 and 0.821, respectively. When combining serum CRP and synovial CRP to diagnose PJI, the AUC was 0.849, which was slightly higher than the result obtained when using serum CRP alone. In contrast, when combining serum IL-6 and synovial IL-6 to diagnose PJI, the AUC increased to 0.940, which was significantly higher than that obtained using serum IL-6 alone. CONCLUSION: The synovial IL-6 has the highest diagnostic accuracy for PJI. However, inferring the level of CRP/IL-6 in the synovial fluid from the serum level of CRP/IL-6 was not feasible. Synovial CRP testing did not offer an advantage when combined with an existing serum CRP result to diagnose PJI, while additional synovial IL-6 was worthy of testing even if there was an existing serum IL-6 result.

Comparison of the success rate after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection among patients with or without a sinus tract.

BACKGROUND: The relevance between the presence of a sinus tract and the failure risk after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection (PJI) after hip or knee arthroplasty is still unclear. This study aimed to compare the success rate of DAIR between patients with or without a sinus tract and to explore the possible risk factors for failure after DAIR in patients with a sinus tract. METHODS: Consecutive DAIR cases for PJI after hip or knee arthroplasty between January 2009 and June 2019 with a minimum 1-year follow-up in two tertiary joint arthroplasty centers were included. Patients were classified into the sinus tract group and the non-sinus tract group according to the presence of a sinus tract. The success rate after DAIR were compared using Kaplan-Meier survival analysis. Potential risk factors for failure in the sinus group were also explored. RESULTS: One hundred seven patients were included. At a median 4.4 years of follow-up, 19 of 52 (36.5%) cases failed in the sinus tract group, while 15 of 55 (27.3%) cases failed in the non-sinus tract group. The 1-year and 5-year cumulative success rates were 71.2% (95% confidence interval (CI): 59.8-84.6%) and 56.8% (95% CI: 42.6-75.7%) in the sinus tract group, respectively, which were similar to the counterparts in the non-sinus tract group (P = 0.214). Among patients with a sinus tract, DAIR with the exchange of modular components showed a higher success rate (75.8% versus 47.4%, P = 0.038). CONCLUSIONS: The presence of a sinus tract does not affect the success rate of DAIR. Modular component exchange in DAIR was proposed for patients with a sinus tract for an improved infection control rate.

Leukocyte esterase test and alpha-defensin test have similar accuracy for the diagnosis of periprosthetic joint infection.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) after total joint replacement remains challenging. Synovial biomarkers are recommended as the major diagnostic criteria for PJI. The purpose of this study was to test the accuracy of the alpha-defensin test and compare it with that of the leukocyte esterase (LE) test for the diagnosis of PJI. METHODS: We obtained 130 hip or knee aspirates from May 2015 to September 2018. PJI was defined according to the European Bone and Joint Infection Society (EBJIS) criteria. Synovial fluid samples were tested with the alpha-defensin ELISA and a LE strip. For the LE strip test, besides using the traditional threshold 500 (equal to ++), we are also using an improved one, with 500 (equal to ++) serving as the threshold for the tests before centrifugation and both 250 and 500 indicating positive results after centrifugation. The receiver operating characteristic (ROC) curves, sensitivity, specificity, positive predictive value, negative predictive value, and Cohen's Kappa value were calculated for the LE and alpha-defensin tests. RESULTS: The area under the curve (AUC) of alpha-defensin, LE strip test with traditional, and improved interpretation strategy were 0.875, 0.854, and 0.877, respectively. The Cohen's Kappa value for the alpha-defensin tests was 0.826 with the traditional LE interpretation strategy and 0.875 with the improved strategy. CONCLUSION: The present study shows that the use of the LE strip to test synovial fluid yielded an accuracy similar to that of the alpha-defensin immunoassay for the diagnosis of PJI; this finding supports the 2018 ICM PJI definition, which considers positive alpha-defensin and LE test results to be equivalent.

The use of augmented antibiotic-loaded cement spacer in periprosthetic joint infection patients with acetabular bone defect.

BACKGROUND: Spacer complications may affect final clinical outcome of the two-stage approach in periprosthetic joint infection (PJI) patients. This study aimed to investigate clinical outcomes and complications of augmented antibiotic-loaded cement spacer in PJI patients with acetabular bone defect. METHODS: Data on PJI patients with acetabular bone defect receiving two-stage revision from January 2009 to December 2016, in our hospital were retrospectively reviewed. Screw-cement-shell was used to improve the stability of the hip with acetabular wall defect. Handmade acetabular spacer could prevent femoral spacer entering into pelvis in patients with acetabular internal wall defect. A total of 26 patients (11 males and 15 females) were included in the current study. Their mean age was 46.7 ± 15.4 years old. Clinical outcomes and complications were measured. RESULTS: Twenty-one of total 26 hips (21/26, 80.8%) showed positive cultures and 15/26 (57.7%) samples were cultured with staphylococcus. Of enrolled patients, 5/26 (19.2%) developed mixed infection. There was one patient (3.8%) with spacer dislocation and two (7.7%) with spacer fracture. One patient developed acute PJI 5 years after the second-stage revision, so overall success rate among these patients was 96.2%. Differences in Paprosky classifications before the first and second stage did not reach significant level (p > 0.05). Hip Harris score was raised from 40.9 ± 14.0 to 81.2 ± 11.2 (p < 0.05). CONCLUSIONS: Augmented antibiotic-loaded cement spacer could achieve satisfactory clinical outcomes in PJI patients with acetabular bone defect. It provided joint mobility, increased additional joint stability, and decreased iatrogenic bone defect caused by acetabular wear.

Neutrophil to lymphocyte ratio as a predictor for diagnosis of early Periprosthetic joint infection.

BACKGROUND: Periprosthetic joint infection (PJI) is a catastrophic complication after total knee or hip arthroplasty. The diagnosis of PJI is very difficult, especially in the early postoperative period. The value of the neutrophil to lymphocyte ratio (NLR) is useful for diagnosing infectious diseases. The objective of this study was to investigate the accuracy of the NLR for the diagnosis of early PJI after total knee or hip arthroplasty. METHODS: We retrospectively evaluated consecutive primary total knee or hip arthroplasty and identified the patients who readmitted within the first 90 days postoperatively between January 2011 and October 2018.There were 20 cases diagnosed early PJI and 101 uninfected cases on the basis of the modified Musculoskeletal Infection Society (MSIS) criteria. The serum parameters including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood-cell (WBC) count, NLR and interleukin-6 (IL-6) were compared between the two groups. Receiver operating characteristic curves were generated to estimate the optimal cutoff values for each parameter. The sensitivity, specificity, positive predictive value and negative predictive value for each parameter were calculated. RESULTS: The CRP, ESR, WBC, NLR and IL-6 values were all significally higher in the infected group than the uninfected group. The median of CRP was 66.6 mg/l in the infected group and 8.6 mg/l in the uninfected group (p < 0.001). The median of ESR was 34.8 mm/hr. in the infected group and 17.4 mm/hr. in the uninfected group (p < 0.001). In the infected group and uninfected group, the median of WBC was 8.2X109 /L and 6.1 X109 /L (p = 0.002), respectively; while the median of NLR was 5.2 and 2.1 (p < 0.001). The median of IL-6 was 46 pg/ml and 6.4 pg/ml (p < 0.001),respectively. The best parameter for the diagnosis of early PJI was IL-6 (AUC = 0.814) followed by the NLR (AUC =0.802), CRP (AUC =0.793), ESR (AUC =0.744) and WBC (AUC = 0.632). CONCLUSIONS: This study is the first to show that NLR values are more accurate than CRP and may be considered as useful parameters for the diagnosis of early PJI because it is a cheap and convenient parameter to be calculated in daily practice without extra costs.

Plasma Fibrinogen Exhibits Better Performance Than Plasma D-Dimer in the Diagnosis of Periprosthetic Joint Infection: A Multicenter Retrospective Study.

BACKGROUND: The search for potential markers for a timely and accurate diagnosis of periprosthetic joint infection (PJI) is ongoing. Previous studies have focused on inflammatory markers and have rarely examined coagulation-related indicators. The purpose of this study was to evaluate the values of plasma fibrinogen, D-dimer, and other blood markers for the diagnosis of PJI through a multicenter retrospective study. METHODS: A total of 565 revision total hip and knee arthroplasty cases were enrolled in this study from January 2016 through December 2017, 126 of which had coagulation-related comorbidities and were analyzed separately. The remaining 439 cases included 76 PJI and 363 non-PJI patients. The definition of PJI was based on the International Consensus Meeting (ICM) on Periprosthetic Infection criteria. The diagnostic values of D-dimer, plasma fibrinogen, the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and white blood-cell (WBC) count were analyzed using receiver operating characteristic (ROC) curves. RESULTS: ROC curves showed that plasma fibrinogen had the highest area under the curve (AUC), 0.852, followed by 2 classical markers, the CRP level and ESR, which had an AUC of 0.810 and 0.808, respectively. D-dimer had an AUC of 0.657, which was the second lowest value and only slightly higher than that of the WBC count, 0.590. The optimal threshold for plasma D-dimer was 1.25 µg/mL, with a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 0.645, 0.650, 0.278, and 0.897, respectively. The optimal threshold for plasma fibrinogen was 4.01 g/L, which showed good sensitivity, specificity, PPV, and NPV, with values of 0.763, 0.862, 0.537, and 0.946, respectively. CONCLUSIONS: Plasma D-dimer may have a very limited diagnostic value for PJI, while plasma fibrinogen, another coagulation-related indicator, exhibits promising performance. Plasma fibrinogen has good sensitivity and specificity for diagnosing PJI, with values similar to those of classical markers, including CRP level and ESR. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Changes in sexual activity of male patients with ankylosing spondylitis undergoing total hip arthroplasty.

INTRODUCTION: Sexual activity is often an important component of life. To date, no studies have examined sexual activity before and after total hip arthroplasty (THA) in male patients with ankylosing spondylitis (AS). The purpose of the current study was to evaluate the effect of THA on sexual activity and to explore the most commonly reported and comfortable coital position for male AS patients with hip involvement. METHODS: Data from 31 male AS patients who underwent THA for hip involvement were retrospectively reviewed. Information from the International Index of Erectile Function (IIEF), the Harris Hip Score (HHS) and other clinical parameters was collected and monitored over time. We compared the above-mentioned parameters before surgery and 2 years after surgery and analysed the correlation between changes on the IIEF and changes in clinical parameters. RESULTS: The domain and total scores of the IIEF, except EF, were significantly higher after surgery than were those before surgery ( p < 0.05). There was a significant positive correlation between changes on the IIEF and improvement in flexion-extension range of motion (ROM), adduction-abduction ROM and HHS ( p < 0.05). Most patients (26/31, 83.9%) resumed sexual activity 5-12 weeks after surgery. The pre- and postoperative distributions of the most commonly reported and comfortable position were not significantly different (p > 0.05). CONCLUSIONS: Successful THA may improve sexual activity in male AS patients with hip involvement. Changes in hip ROM show the most significant correlation with improvement in sexual activity. Resumption of sexual activity occurs within 5-12 postoperative weeks.

Robot-assisted vs. conventional unicompartmental knee arthroplasty : Systematic review and meta-analysis.

Numerous advances have been made in prosthesis design, instrumentation and postoperative rehabilitation for unicompartmental knee arthroplasty; however, only 70-86% of patients are satisfied with the functional outcome and revision rates range between 10% and 20%. The primary outcome for this meta-analysis was implantation accuracy of component positioning and tibiofemoral component safe zone. A total of three randomized controlled trials (RCT), three quasi-RCTs and one prospective trial were included in this review. It was found that the use of robotic-assisted systems reduces implantation errors without an increase in adverse events. There are only a few reports about clinical outcome and long-term follow-up and whether the more accurate component positioning results in a better clinical effect or a better long-term survival of the implants is unknown.

Meta-analysis of sonication prosthetic fluid PCR for diagnosing periprosthetic joint infection.

Periprosthetic joint infection (PJI) is a catastrophic complication following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with difficulties, which is characterized by technical limitations. The question of whether sonication fluid PCR can provide high value in the diagnosis of PJI remains unanswered. This meta-analysis included 9 studies that evaluated PCR assays of sonication fluid for the diagnosis of PJI. The pooled sensitivity, specificity, Positive likelihood ratio (PLR), Negative likelihood ratio (NLR) and Diagnostic odds ratio (DOR) were 0.75 (95% confidence interval [CI], 0.71 to 0.81), 0.96 (CI, 0.94 to 0.97), 18.24 (CI, 6.07 to 54.78), 0.27 (CI, 0.20 to 0.36) and 86.97 (CI, 37.08 to 203.97), respectively. The AUC value of the SROC was 0.9244 (standard error, 0.0212). Subgroup analyses showed that use of multiplex PCR and may improve sensitivity and specificity. The results of this meta-analysis showed that PCR of fluid after sonication is reliable and of great value in PJI diagnosis.

Risk factors and clinical characteristics of deep knee infection in patients with intra-articular injections: A matched retrospective cohort analysis.

BACKGROUND: Deep knee infection (DKI), consisting of sepsis arthritis (SA) and chronic low-grade infection (CLGI), is a rare but catastrophic adverse event that can result from intra-articular (IA) injections. The purpose of this study was to assess the risk factors for DKI and describe the clinical characteristics of DKI in patients who received IA injections. METHODS: Fifty patients with IA injection-induced DKI who underwent surgical treatment between January 2010 and May 2016 served as cases and were matched with non-infected controls who received IA injections in a proportion of 1:5 based on age, gender, and date of admission. All IA injections (both cases and controls) were performed within 6 months of admission at our institution or at a referring institution. Risk factors for injection-induced DKI were analyzed, and the clinical characteristics between SA and CLGI were compared. RESULTS: The final multivariate logistic regression analysis demonstrated that body mass index ≥25kg/m2 [odds ratio (OR) = 2.3; 95% confidence interval (CI): 1.1-4.7], corticosteroid injections (OR = 3.21; 95% CI: 1.63-6.31), rheumatoid arthritis (OR = 2.61; 95% CI: 1.20-5.68) and injections performed by general practitioners (OR = 5.23; 95% CI: 2.00-13.67) increased the risk of DKI following IA injections. Of 50 cases, there were 21 SA cases and 29 CLGI cases. SA cases had significantly higher metrics in the categories of fever, local warmth, swelling, rest pain, night pain, limited motion, serum WBC, and CRP levels than CLGI cases. CONCLUSIONS: We identified risk factors and clinical characteristics of injection-induced DKI, which may offer improved guidance on IA injections and knowledge of DKI in patients with IA injections, especially in CLGI patients.

Comparison of Leukocyte Esterase Testing of Synovial Fluid with Synovial Histology for the Diagnosis of Periprosthetic Joint Infection.

BACKGROUND Periprosthetic joint infection (PJI) is a complication of total joint arthroplasty (TJA). The leukocyte esterase (LE) strip test and histology are diagnostic methods for PJI. The aims of this study were to determine the sensitivity and specificity of the LE strip test and to compare it with histology in the diagnosis of PJI. MATERIAL AND METHODS Between January and December 2015, 93 patients who underwent TJA with PJI were enrolled in the study. Synovial fluid samples were tested with an LE strip, and three synovial tissue samples from each patient underwent frozen section and formalin-fixed histology. Recent criteria from the Musculoskeletal Infection Society (MSIS) were used for the diagnosis of PJI. RESULTS Ninety-three patients studied included 38 cases of PJI and 55 non-infected cases. Sensitivity and specificity of the LE strip test were 92.1% (95% CI, 77.5-97.9%) and 96.4% (95% CI, 86.4-99.4%), respectively. There was no significant difference in sensitivity (p=0.249) or specificity (p=0.480) between frozen and paraffin sections for histology; the two methods were strongly correlated (φ=0.892). Comparison of the LE test results with histology showed a strong correlation (φ=0.758, and φ=0.840). CONCLUSIONS The findings of this preliminary study have shown that the LE strip test on synovial fluid showed similar sensitivity and specificity as histology for the diagnosis of PJI, indicating that that further controlled clinical studies should be performed to investigate the role of the LE strip test for the early diagnosis of PJI.