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Synovial leukocyte count analysis is an important tool in the diagnosis of PJI. However, results can be poor if metallosis is present. The issue of metallosis was established for some rotating hinge knee arthroplasty designs. This was a retrospective single-center analysis that included 108 patients who had a single-design metal-on-metal rotating hinge knee arthroplasty who underwent revision surgery and had prior synovial fluid analysis performed. The diagnostic accuracy of leukocyte count and the percentage of polymorphonuclear neutrophiles (% PMN) were investigated. Patients who had a PJI had a higher median leukocyte count and % PMN compared to aseptic revisions (7,905/μL (interquartile range (IQR) 2,419 to 37,400) and 85% (IQR 70.3 to 93.8) versus 450 (IQR 167 to 1,215) and 46% (IQR 28.5 to 67.4%), P <.001). The respective areas under the curves were 0.916 (95% confidence interval 0.862 to 0.970) for leukocyte count and 0.821 (95% confidence interval 0.739 to 0.902) for % PMN. We calculated an optimal cut-off value of 1,200 leukocytes/μL (Sensitivity 94.5%/specificity 75.5%) and 63% PMN (Sensitivity 85.5%/specificity 73.6%) to define PJI. Established thresholds were less sensitive, but more specific. The "infection likely" scenario of the European Bone and Joint Infection Society (EBJIS) definition was closest to the calculated thresholds. Currently used thresholds for leukocyte cell count and %PMN to define PJI were less sensitive and specific in the diagnosis of PJI in metal-on-metal RHK knees. Surgeons must consider lower cut-off values when evaluating such implants for PJI. [ABSTRACT FROM AUTHOR]

The diagnosis of persistent infection prior to second-stage reimplantation in 2-stage exchanges for periprosthetic joint infection (PJI) can be challenging as there is no optimal diagnostic tool. This study investigates the usefulness of pre-reimplantation serum C-reactive protein (CRP) and interleukin-6 (IL-6) and its change between both stages to identify patients who have subsequent PJI. There were 125 patients who underwent planned 2-stage exchange for chronic knee or hip PJI from a single center retrospectively identified. Patients were included if preoperative CRP and IL-6 were available for both stages. Subsequent PJI was defined as 2 positive microbiological cultures at reimplantation or subsequent surgery or death due to PJI during follow-up. Prior to reimplantation, the median serum CRP (total knee arthroplasties [TKAs]: 1.0 versus 0.5 mg/dL, P =.028; total hip arthroplasties [THAs]: 1.3 versus 0.5 mg/dL, P =.015) and median IL-6 (TKA: 8.0 versus 6.0 pg/mL, P =.052; THA: 7.0 versus 6.0 pg/mL, P =.239) were higher in patients who had subsequent PJI. The IL-6 and CRP values showed moderate sensitivity (TKA/CRP: 66.7%; THA/CRP: 58.8%; TKA/IL-6: 46.7%; THA/IL-6: 35.3%) and good specificity (TKA/CRP: 66.7%; THA/CRP: 81.0%; TKA/IL-6: 86.3%; THA/IL-6: 83.3%). The change in CRP and IL-6 between the stages did not differ between the groups, respectively. Serum CRP and IL-6 show low to moderate sensitivity and good specificity in the diagnosis of subsequent PJI prior to reimplantation, which questions their usefulness as a rule-out test. Furthermore, the change in between stages does not appear to identify subsequent PJI. [ABSTRACT FROM AUTHOR]

Chronic periprosthetic joint infection after revision hip and knee arthroplasties can lead to subsequent massive femoral bone loss. In these cases, resection of the residual femur and placement of an antibiotic total femoral spacer can be an option to salvage the limb. This is a single-center retrospective analysis of 32 patients (median age 67 years; range 15-93; 18 women) who underwent placement of a total femur spacer for chronic periprosthetic joint infection with massive femoral bone loss between 2010 and 2019 as part of a planned two-stage exchange. The median follow-up period amounted to 46 months (range, 1-149). Implant and limb survival were analyzed using Kaplan-Meier survival estimates. Potential risk factors for failure were analyzed. There were 34% (11 of 32) of patients having a spacer-associated complication, and 25% underwent revision for this reason. After the first stage, 92% were considered infection-free. There were 84% of patients who underwent second-stage reimplantation of a total femoral arthroplasty using a modular megaprosthetic implant. Infection-free implant survival was 85% after 2 years and 53% after 5 years. There were 44% of patients who underwent amputation after a median time of 40 months (range, 2-110). Most commonly, coagulase-negative staphylococci were cultured at first-stage surgery, while polymicrobial growth was most common at reinfection. Total femur spacers can lead to infection control in over 90% of cases with a reasonable complication rate for the spacer itself. However, the reinfection and subsequent amputation rate after second-stage megaprosthetic total femoral arthroplasty is around 50%. [ABSTRACT FROM AUTHOR]

Background: Unsuspected positive cultures (UPCs) may be found at the time of planned aseptic revision surgery and have previously been associated with decreased implant survival. However, reported rates vary greatly, and potential risk factors are widely unknown. This study investigates the rate of UPCs, implant survival, as well as potential risk factors for UPCs and revision.Methods: This is a retrospective, single-center study on 434 cases of total hip arthroplasty (THA 277) and knee revision arthroplasty (TKA 157) performed between 2010 and 2017. Microbiology culture results, revision-free survival (RFS) and infection-free (IFS) survival, and the potential impact of UPCs as well as patient- or procedure-related risk factors were investigated at a minimum follow-up of 24 months (median 41 months).Results: A total of 37% of patients had a positive culture (160/434). 27% (119/434) had a solitary positive culture, and 9% (41/434) had ≥2 positive cultures of the same species. Most commonly, coagulase-negative staphylococci were cultured. Overall, 32% (13/41) of patients with ≥2 positive cultures underwent revision for infection compared with 6% (17/274) of patients with negative cultures. RFS and IFS were reduced if ≥2 cultures were positive. Single positive cultures had no impact on RFS or IFS. Male sex, elevated serum C-reactive protein, and obesity were independently associated with finding ≥2 UPCs in revision THA.Conclusion: Appearance of ≥2 UPCs in aseptic revision leads to reduced RFS and IFS. Males, obese patients, and patients with elevated serum C-reactive protein planned for THA revision should be considered for extended diagnostics to rule out periprosthetic joint infection. [ABSTRACT FROM AUTHOR]

Background: Spouses are the primary caregivers of patients living with osteoarthritis (OA). Little is known about how the quality of life (QoL) of OA patients' partners change after total joint replacement surgery (TJR).Methods: Preoperative health status and 12-month postoperative outcomes were evaluated and compared in 24 couples using the Short-Form 36 (SF-36), knee or hip specific Osteoarthritis Outcome Score (OOS) and accelerometry for the assessment of habitual physical activity (PA) and sedentary behavior (SB). Correlations between the changes in the patients' OOS subscales scores, habitual activity, and their partners' SF-36 scores were calculated.Results: Following TJR the patients' OOS subscale scores showed positive changes (P < .001). The SF-36 physical component summary (PCS) score improved (P < .001), while the mental component summary (MCS) score as well as PA and SB remained unchanged (P ≥ .093). Their partners' PCS, MCS, and SB did not change (P ≥ .286), whereas the PA even decreased (P = .027). Correlation analyses showed positive results for the changes in the patients' OOS subscale pain and the changes in their partners' MCS (r = 0.355, P = .048) as well as the changes in the patients' OOS subscale activities of daily living and the changes in the PCS of their partners (r = 0.406, P = .027). In contrast to the results described above, changes in the patients' PA were negatively correlated with changes in their partners' PCS (r = -0.389, P = .033).Conclusion: TJR has a positive influence on QoL but not the habitual activity of OA patients. Their partners, on the other hand, show no changes in QoL and even a slight decrease in habitual activity. [ABSTRACT FROM AUTHOR]

Background: Two-stage exchange using antibiotic-loaded spacers is a common approach in treating periprosthetic joint infections. Acute kidney injury (AKIN) can be a systemic complication of this procedure. This study investigates the prevalence of AKIN and identifies potential risk factors.Methods: This is a single-center retrospective analysis of patients undergoing 2-stage exchange using a spacer in 285 patients treated between 2010 and 2017. Risk factors were evaluated using parametric and nonparametric analyses and a multivariate, binary logistic regression model.Results: Thirty-three percent of patients (95/285) developed an AKIN postoperatively. Twenty-four percent (23/95) of these patients had an acute on chronic kidney failure with a previously impaired renal function. In multivariate analysis, a higher age (hazard ratio [HR], 1.034; 95% confidence interval [CI], 1-1.068; P = .046) and a higher baseline creatinine level (HR, 1.94; 95% CI, 1.237-3.052; P = .004) were risk factors for AKIN. Treatment with vancomycin in the spacer or systemically was not associated with AKIN while a high vancomycin blood level (HR, 1.91; 95% CI, 0.913-3.992; P = .086) and fungal infections were (HR, 3.482; 95% CI, 0.968-12.521; P = .056). Furthermore, in univariate analysis, a higher median Charlson comorbidity index (4 vs 3, P = .007), a lower preoperative hemoglobin (10.9 vs 11.7 g/dL, P = .008), and a higher number of blood transfusions (1 vs 0, P = .004) were associated with AKIN.Conclusion: AKIN is common in patients undergoing 2-stage exchange. Associated patient factors, particularly in patients with chronic renal dysfunction, should be optimized. The general use of glycopeptide antibiotics was no risk factor for AKIN. [ABSTRACT FROM AUTHOR]

Background: Soft tissue deficiency in total knee arthroplasty infection is a potentially devastating complication. Gastrocnemius muscle flaps can be used to address this problem. We aim at reporting survival rates of these reconstructions and identify risk factors for failure.Methods: A retrospective evaluation of all flaps performed at a single center between 2006 and 2019 was performed. Clinical and microbiological results were assessed in 43 cases after a median follow-up period of 53 months (25%-75% interquartile range 18-79). Function was assessed using the Oxford Knee Score. We analyzed the infection-free survival and identified risk factors using survival comparison and (non-)parametric testing.Results: Infection-free survival was 71% at 2 years and 63% at 5 years. The rate of subsequent amputation was 16% with a mortality rate of 26% during follow-up. Four patients did not undergo reimplantation and 11 patients received an arthrodesis implant. There were no failures of the flap itself. The Charlson Comorbidity index was the only relevant risk factor for reinfection. Coagulase-negative staphylococci were most common organisms identified. Postoperative function was limited with a mean Oxford Knee Score of 20.Conclusion: Gastrocnemius flap coverage is a valid option for soft tissue reconstruction in periprosthetic infections to retain a functioning limb despite a high complication rate and the risk of subsequent amputation. [ABSTRACT FROM AUTHOR]

Background: Hemiarthroplasty megaprosthetic proximal femur reconstruction after tumor resection is a widespread procedure in orthopedic oncology. One potential complication is acetabular wear requiring secondary acetabular revision. The study's purpose is to investigate prevalence of acetabular erosion, secondary revisions, and potential risk factors.Methods: We retrospectively identified 112 patients who underwent proximal femur replacement after resection of a malignant bone tumor and had radiological follow-up longer than 12 months. Patient demographic, surgical, and oncologic factors were recorded, acetabular wear was measured using the classification proposed by Baker, and prosthetic failure was classified using the International Society on Limb Salvage classification. Functional assessment was performed using the Musculoskeletal Tumor Society Score and Harris Hip Score.Results: Prevalence of acetabular wear was 28.6%. Secondary conversion to total hip arthroplasty was required in 5 patients (4.6%), all treated for primary bone tumors. No patient treated for metastatic tumor had higher grade acetabular wear or required revision. Significant risk factors for the development of acetabular wear were age under 40 (P = .035) and longer follow-up (63 vs 43 months, P = .004). Other patient, surgical, or adjuvant treatment-related factors were not associated with acetabular revision or acetabular wear. The dislocation rate in the patient cohort was 0.9%.Conclusion: Bipolar hemiarthroplasty proximal femoral replacement represents a durable reconstruction after tumor resection. Hip instability is rare. Acetabular erosion is rare and can be successfully treated with conversion to total hip arthroplasty. Young patients with long-term survival over 10 years are at risk. In reconstruction for metastases, instability and acetabular wear are rare. [ABSTRACT FROM AUTHOR]

We report outcomes of 28 patients after stump-lengthening procedures (SLPs) with modular tumor endoprostheses following high-thigh amputation and hip disarticulation over 11 years. Mean follow up was 41.3 months (range 7.4 to 133.6 months). Mean Musculoskeletal Tumour Society Score was 56% (n = 11); ten out of eleven patients alive used an exoprosthesis regularly. Complications occurred in 15 patients with infection being most common. In 2 cases, the prostheses had to be explanted. Our data suggest that SLP facilitates post-operative rehabilitation and prosthesis usage. Modular endoprostheses for stump-lengthening allow optimization of remnant soft-tissue envelope, reducing the risk of stump perforation. [ABSTRACT FROM AUTHOR]

Abstract: We reviewed outcomes and discussed surgical difficulties encountered in 10 patients who had modular endoprosthesis for limb preserving salvage of failed allograft reconstruction after malignant tumor resection. Mean allograft survival time before failure was 127.4 months (range, 14-264 months). Mean length of follow-up since endoprosthesis revision surgery was 62.8 months (range, 16-132 months). There was one endoprosthesis failure, resulting in a mean endoprosthesis survival time of 56.9 months (range, 16-132). Complications included arterial laceration, nerve injury, periprosthetic crack fracture, aseptic loosening, and infection. Modular endoprosthesis remain a viable option that should be considered in any limb preserving salvage of failed allograft reconstructions. However, altered anatomy, poor/short remnant host bone, periprosthetic fractures, inadequate soft tissue coverage and infection remain important difficulties encountered. [Copyright &y& Elsevier]

Abstract: We retrospectively reviewed 197 patients who underwent reconstruction with a megaprosthesis of the lower extremity. A cobalt-chrome alloy system was used in 77 patients and a titanium alloy system in 120 patients. The overall infection rate was 20.8% (n = 41). Separated into the 2 prosthesis systems used, an infection rate of 31.2% was found in the patients with a cobalt-chrome-alloy prosthesis and 14.2% in the titanium alloy group of patients (P < .01). Early infection occurred in 5.1% (n = 10) and late infection in 15.7% (n = 31). Selecting 2 identical subgroups for further analysis, the cobalt-chrome alloy prostheses were associated with a significantly higher infection rate, with 5 infections of 26 megaprostheses vs 1 infection of 36 titanium megaprostheses (P < .05). [Copyright &y& Elsevier]

Background: Little is known about the resumption of sporting activities following megaprosthetic reconstruction of the distal femur and proximal tibia after resection of a bone sarcoma. Thus, the aims of our study were: (1) to assess the functional outcome; (2) to evaluate pre- and post-operatively performed sporting activities; and (3) to identify potential beneficial and limiting factors., Methods: Between 1993 and 2015, a total of 230 patients underwent distal femoral replacement (DFR), and 96 patients underwent proximal tibial replacement (PTR). The exclusion criteria were death, amputation, living overseas, and a congenital disability. Functional outcome and sporting activities were assessed using the Musculoskeletal Tumor Society Score (MSTS), Toronto Extremity Salvage Score (TESS), Forgotten Joint Score (FJS), subjective knee value (SKV), the Tegner activity score (TS), and the modified weighted activity score (WAS)., Results: There were 93 patients who had a median follow-up of 182 months (interquartile range (IQR) 130 to 260) after DFR with the following median scores: MSTS 18 (IQR 12 to 23), TESS 75% (IQR 60 to 84), FJS 25 (IQR 8 to 40), SKV 53% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 0 to 8). There were 42 patients who had a median follow-up of 193 months (IQR 137 to 244) after PTR had the following median scores: MSTS 17 (IQR 15 to 22), TESS 78% (IQR 68 to 88), FJS 32 (IQR 20 to 46), SKV 60% (IQR 40 to 70), TS 3 (IQR 3 to 4), and WAS 4 (IQR 1 to 10). Postoperatively, 61% of DFR and 76% of PTR patients participated in at least one sporting activity., Conclusions: The functional outcome is overall good with a regular resumption of sporting activities. Patients' age at surgery and higher preoperative sporting levels were associated with better functional outcomes and higher postoperative sporting activity., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)