Serum D-Lactate, a Novel Serological Biomarker, Is Promising for the Diagnosis of Periprosthetic Joint Infection

Background: Although many markers are used for diagnosis of periprosthetic joint infection (PJI), serological screening and diagnosis for PJI are still challenging. We evaluated the performance of serum D-lactate and compared it with ESR, coagulation-related biomarkers and synovial D-lactate for the diagnosis of PJI.Methods: Consecutive patients with preoperative blood and intraoperative joint aspiration of a prosthetic hip or knee joint before revision arthroplasty were prospectively included. The diagnosis of PJI was based on the criteria of the Musculoskeletal Infection Society, and the diagnostic values of markers were estimated based on receiver operating characteristic (ROC) curves by maximizing sensitivity and specificity using optimal cutoff values.Results: Of 52 patients, 26 (50%) were diagnosed with PJI, and 26 (50%) were diagnosed with aseptic failure. ROC curves showed that serum D-lactate, fibrinogen (FIB) and ESR had equal areas under the curve (AUCs) of 0.80, followed by D-dimer and fibrin degradation product, which had AUCs of 0.67 and 0.69, respectively. Serum D-lactate had the highest sensitivity of 88.46% at the optimal threshold of 1.14 mmol/L, followed by FIB and ESR, with sensitivities of 80.77% and 73.08%, respectively, while there were no significant differences in specificity (73.08%, 73.08% and 76.92%, respectively). Conclusion: Serum D-lactate showed similar performance to FIB and ESR for diagnosis of PJI. The advantages of serum D-lactate are pathogen-specific, highly sensitive, minimally invasive and rapidly available making serum D-lactate useful as a point-of-care screening test for PJI.

Favourable outcomes of repeat one-stage exchange for periprosthetic joint infection of the hip

Aims One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure. Methods We retrospectively reviewed all repeat one-stage revision THAs performed after failed one-stage exchange THA for infection between January 2008 and December 2016. The final cohort included 32 patients. The mean follow-up after repeat one-stage exchange was 5.3 years (1.2 to 13.0). The patients with a further infection-related failure and/or all-cause revision were reported, and Kaplan-Meier survival for these endpoints determined. Patients were categorized according to the MSIS system, and its association with further infection was analyzed. Results A total of eight repeat septic revisions (25%) developed a further infection-related failure, and the five-year infection-free survival was 81% (95% confidence interval (CI) 57 to 92). Nine (28%) underwent a further all-cause revision and the five-year all-cause revision-free survival was 74% (95% CI 52 to 88). Neither the MSIS classification of the host status (p = 0.423) nor the limb status (p = 0.366) was significantly associated with further infection-related failure. Conclusion Repeat one-stage exchange for PJI in THA is associated with a favourable five-year infection-free and all-cause revision-free survival. Notably, the rate of infection control is encouraging when compared with the reported rates after repeat two-stage exchange. The results can be used to counsel patients and help clinicians make informed decisions about treatment. With the available number of patients, further infection-related failure was not associated with the MSIS host or limb status. Cite this article: Bone Joint J 2022;104-B(1):27–33.

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.

Experiences during Switching from Two-Stage to One-Stage Revision Arthroplasty for Chronic Total Knee Arthroplasty Infection

The objective of this study was to evaluate our preliminary results after changing our surgical strategy from 2-stage revision arthroplasty to 1-stage revision arthroplasty for patients with chronic knee periprosthetic joint infection. We conducted a prospective study of knee arthroplasty patients that had been diagnosed with chronic infection and treated using a 1-stage revision regardless of the traditional criteria applied for indication thereof. We evaluated two main variables: infection control and economic costs. The definitive diagnosis of infection of the revision was determined by using the criteria proposed by the Musculoskeletal Infection Society. The costs were calculated as average costs in USD, as described by Srivastava (2019), for 1-stage or 2-stage revisions. Eighteen patients were included in the study, and infection was controlled in 17 patients. The total economic savings for our hospital from these 18 patients amounted to USD 291,152. This clinical success has led to major changes in how our hospital approaches the treatment of chronically infected knee replacements, in addition to substantial economic advantages for the hospital.

Outcomes of the gastrocnemius flap performed by orthopaedic surgeons in salvage revision knee arthroplasty

Introduction: The gastrocnemius myofascial flap is used to manage soft-tissue defects over the anterior aspect of the knee in the context of a patient presenting with a sinus and periprosthetic joint infection (PJI) or extensor mechanism failure. The aim of this study was twofold: firstly, to evaluate the outcomes of gastrocnemius flaps performed by appropriately trained orthopaedic surgeons in the context of PJI and, secondly, to evaluate the infection-free survival of this patient group. Patients and methods: We retrospectively reviewed 30 patients who underwent gastrocnemius flap reconstruction during staged revision total knee arthroplasty for prosthetic joint infection (PJI). All flaps were performed by an orthopaedic surgeon with orthoplastics training. Patients had a mean age of 68.9 years (range 50–84) and were followed up for a mean of 50.4 months (range 2–128 months). A total of 29 patients (97 %) were categorized into Musculoskeletal Infection Society (MSIS) local extremity grade 3 (greater than two compromising factors), and 52 % of PJIs were polymicrobial. The primary outcome measure was flap failure, and the secondary outcome measure was recurrent infection. Results: Flap survival was 100 % with no failures or early returns to theatre for flap problems such as necrosis or haematoma. Overall infection-free survival during the study period was 48 % (13 of 27 infected cases). Using limb salvage as the outcome, 77 % (23 of 30 patients) retained the limb. Infection recurrence occurred in 48 % (10 patients) in the type B3 cohort and 67 % (4 patients) in the type C3 cohort (p=0.65). Conclusions: The surgical technique for a gastrocnemius myofascial flap is reliable and reproducible when performed by appropriately trained orthopaedic surgeons, even in high-risk groups. However, the risks of recurrent infection and amputation remain high within our series due to poor host and extremity factors.

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.

¿Qué factores hacen fallar un reimplante de cadera luego de una revisión en dos tiempos?

Introducción: El objetivo del estudio fue analizar la supervivencia sin recurrencia de infección en pacientes con reemplazo total de cadera tratados con revisión en dos tiempos, valorando el impacto del cultivo intraoperatorio y la congelación positiva en el reimplante. Materiales y Métodos: Estudio retrospectivo de 96 casos con infección periprotésica crónica, según los criterios de la MusculoSkeletal Infection Society, sometidos a los dos tiempos quirúrgicos en nuestra institución, entre 2008 y 2013. El seguimiento promedio fue 90 meses. La falla séptica se definió sobre la base de un consenso tipo Delphi modificado. La supervivencia sin falla séptica se definió sobre la base del estimador de Kaplan-Meier. Se compararon los resultados de supervivencia en función del cultivo intraoperatorio y de los estudios de anatomía patológica por congelación mediante la prueba del orden logarítmico. Resultados: La supervivencia sin falla séptica fue del 82,65% a los 2 años (IC95% 73,25-88,99%), 80,40% a los 5 años (IC95% 70,70-87,17%) y 77,32% a 6-10 años (IC95% 66,90-84,33%). Hubo significativamente más fallas en los pacientes con un cultivo positivo en el reimplante que en aquellos con un cultivo negativo (prueba del orden logarítmico, p = 0,0208), y en quienes tuvieron un estudio anatomopatológico por congelación positivo en el reimplante que en aquellos con un resultado negativo (prueba del orden logarítmico, p = 0,0154). Conclusiones: Los reimplantes sin recurrencias infecciosas por, al menos, 6 años tuvieron un riesgo de falla séptica muy bajo. Cuando se detectó un cultivo o una congelación positivos, la falla séptica fue significativamente mayor.

Thromboelastography parameters in diagnosing periprosthetic joint infection and predicting reimplantation timing

Background Coagulation-related biomarkers are drawing new attention in the diagnosis of periprosthetic joint infection (PJI). The thromboelastography (TEG) assay provides a comprehensive assessment of blood coagulation; therefore, it could be a promising test for PJI. This study aims to assess the value of TEG in diagnosing PJI and to determine the clinical significance of TEG in analysing reimplantation timing for second-stage revision. Methods From October 2017 to September 2020, 62 patients who underwent revision arthroplasty were prospectively included. PJI was defined by the 2011 Musculoskeletal Infection Society criteria, in which 23 patients were diagnosed with PJI (Group A), and the remaining 39 patients were included as having aseptic loosening (Group B). In group A, 17 patients completed a two-stage revision in our centre. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), D-dimer, and TEG parameters (clotting time, α-angle, MA [maximum amplitude], amplitude at 30 min, and thrombodynamic potential index) were measured preoperatively in all included patients. In addition, receiver operating characteristic curves were used to evaluate the diagnostic value of these biomarkers. Results ESR (area under curve [AUC], 0.953; sensitivity, 81.82; specificity, 94.87) performed best for PJI diagnosis, followed by MA (AUC, 0.895; sensitivity, 82.61; specificity, 97.44) and CRP (AUC, 0.893; sensitivity, 82.61; specificity, 94.74). When these biomarkers were combined in pairs, the diagnostic value improved compared with any individual biomarker. The overall success rate of the two-stage revision was 100%. Furthermore, ESR and MA were valuable in determining the time of reimplantation, and their values all decreased below the cut-off values before reimplantation. Conclusion TEG could be a promising test in assisting PJI diagnosis, and a useful tool in judging the proper timing of reimplantation.