Bilateral Acrylic Hip Mold Arthroplasty in a Child With a Revision 60 years After Implantation: Clinical Case and Chemical Analysis of Endoprosthetic Material.

A 68-year-old man was referred due to bilateral hip pain and gradual deterioration of walking. He had mold arthroplasties on both hips at the age of 7 years and has been functioning well for more than 5 decades. However, the original data on operative report and the prostheses were missing. The radiological examination revealed bilateral broken prosthetic material. Thus, stage bilateral revision total hip arthroplasty was performed. A detailed chemical analysis of retrieved mold arthroplasty implants proved that the acrylic material was noted to be the same composition with the difference in appearance likely being related to different thermal treatments originally applied to the implants. As presented in our clinical case, even obsolete implants may have good survivorship. According to the case presented, total hip arthroplasty could be considered an effective option with the desired functional outcome when conservative and joint-preserving measures are exhausted.

An Upper-Arm Clostridium perfringens Fracture-Related Infection: A Case Report.

CONCLUSION: Fracture-related infections (FRI) pose serious complications, requiring swift surgical intervention. Although C. perfringens infections in FRIs are rare and literature is scarce, this case highlights the successful management and good functional outcome, offering valuable insights for clinicians dealing with such infections.

Psychometric Characteristics, Cross-Cultural Adaptation and Validation of the Slovenian Version of the Victorian Institute of Sports Assessments for Gluteal Tendinopathy Questionnaire (VISA-G).

Introduction: Greater trochanteric pain syndrome (GTPS) denotes several disorders around the lateral aspect of the hip. GTPS may develop in native hips as well as after total hip arthroplasty (THA). It is estimated that 5-12% of patients suffer from GTPS after primary THA. Despite the prevalence of GTPS, it is hard to diagnose and manage it properly. The VISA-G questionnaire was developed as a patient-reported outcome measurement tool for evaluation of GTPS. The aims of the present study were to evaluate the reliability of the VISA-G Slovenian and its construct and criterion validity. Methods: After the finalization of the VISA-G Slovenian translation procedure, 59 patients with a painful trochanteric region planned for THA filled in the VISA-G Slovenian at the hospital on two occasions 5-7 days apart. On the first occasion, each patient also filled in the EQ-5D-5L questionnaire and the Harris Hip Score (HHS) was completed by the physiotherapist. Results: The VISA-G Slovenian was found to have a test-retest reliability of ICC 0.977; 95% CI [0.96; 0.986]. Internal consistency was assessed with Cronbach's alpha 0.79. The statistically significant, but low, correlation between the HHS and VISA-G (r=0.48) was obtained. Concurrent validity of the VISA-G with the EQ-5D-5L showed moderate to strong correlations in Mobility, Self-Care, Usual Activities, Pain, EQ-5D-5L Index and EQ VAS, but low correlation in the Anxiety subscale. No floor and ceiling effect were obtained. Conclusions: The VISA-G Slovenian has excellent psychometric properties needed to measure gluteal tendinopathy-related disability of patients in Slovenia. Thus, we recommend using the questionnaire for measuring trochanteric hip pain.

Implant Survival of 680 Consecutive EcoFit® Flat Single-Wedge Cementless Femoral Stems is Equivalent to the Taperloc® Total Hip Arthroplasty Series.

Introduction: The EcoFit® total hip endoprosthesis has recently been approved for clinical use in the USA as a substantially equivalent implant to the Taperloc® Hip System, but no report has directly compared their long-term results so far. The primary aim of the presented single-hospital EcoFit® cohort analysis was to determine femoral stem survival rates at 5/10 years of follow-up in comparison to eight Taperloc® studies published within the last decade (2011-2021). The secondary aim was to find out whether femoral stem survival depended on the patients' age, gender and the operating surgeon. Materials and Methods: The retrospective surgeon-stratified observational cohort study included 680 consecutive patients with primary EcoFit® femoral stem implanted at the same operating theatre block of a single tertiary hospital between April 2009 and December 2015. Survival analyses after 6-12 years of follow-up were performed with the Kaplan-Meier method and the Cox regression. Results: The cumulative proportion of revision-free surviving EcoFit® femoral stems 5/10 years after the primary implantation was 96/94%, respectively, and the cumulative proportion of unremoved stems was 99/98%, respectively. The EcoFit® stem revision rate of 0.46 per 100 components-years was not significantly different from most Taperloc® cohorts. Higher age increased the risk of subsequent EcoFit® femoral stem revision (hazard ratio 1.039, p = 0.048) while the impact of gender and the operating surgeon was not statistically significant. Conclusions: The study presents the first surgeon-stratified cohort analysis of the EcoFit®-Implantcast femoral stem from a single hospital with 5851 component years of observation. Long-term EcoFit® survival rates are comparable to the Taperloc® hip system. Caution is warranted when using such flat cementless single-wedge stems in the elderly population.

The Role of Inflammasomes in Osteoarthritis and Secondary Joint Degeneration Diseases.

Osteoarthritis is age-related and the most common form of arthritis. The main characteristics of the disease are progressive loss of cartilage and secondary synovial inflammation, which finally result in pain, joint stiffness, and functional disability. Similarly, joint degeneration is characteristic of systemic inflammatory diseases such as rheumatoid arthritis and gout, with the associated secondary type of osteoarthritis. Studies suggest that inflammation importantly contributes to the progression of the disease. Particularly, cytokines TNFα and IL-1ß drive catabolic signaling in affected joints. IL-1ß is a product of inflammasome activation. Inflammasomes are inflammatory multiprotein complexes that propagate inflammation in various autoimmune and autoinflammatory conditions through cell death and the release of inflammatory cytokines and damage-associated molecule patterns. In this article, we review genetic, marker, and animal studies that establish inflammasomes as important drivers of secondary arthritis and discuss the current evidence for inflammasome involvement in primary osteoarthritis. The NLRP3 inflammasome has a significant role in the development of secondary osteoarthritis, and several studies have provided evidence of its role in the development of primary osteoarthritis, while other inflammasomes cannot be excluded. Inflammasome-targeted therapeutic options might thus provide a promising strategy to tackle these debilitating diseases.

Regulation of protein secretion through chemical regulation of endoplasmic reticulum retention signal cleavage.

Secreted proteins, such as hormones or cytokines, are key mediators in multicellular organisms. Response of protein secretion based on transcriptional control is rather slow, as it requires transcription, translation and transport from the endoplasmic reticulum (ER) to the plasma membrane via the conventional protein secretion (CPS) pathway. An alternative regulation to provide faster response would be valuable. Here we present two genetically encoded orthogonal regulatory secretion systems, which rely on the retention of pre-synthesized proteins on the ER membrane (membER, released by a cytosolic protease) or inside the ER lumen (lumER, released by an ER-luminal protease), respectively, and their release by the chemical signal-regulated proteolytic removal of an ER-retention signal, without triggering ER stress due to protein aggregates. Design of orthogonal chemically-regulated split proteases enables the combination of signals into logic functions. Its application was demonstrated on a chemically regulated therapeutic protein secretion and regulated membrane translocation of a chimeric antigen receptor (CAR) targeting cancer antigen. Regulation of the ER escape represents a platform for the design of fast-responsive and tightly-controlled modular and scalable protein secretion system for mammalian cells.

Cohort analysis of two thousand nine hundred forty-three Link Lubinus SP II cemented total hip arthroplasties from a single hospital with surgeon stratification and twenty six thousand, nine hundred and eighty one component-years of follow-up.

PURPOSE: Cemented total hip endoprosthesis Link Lubinus SP II has been used for decades with very good results in arthroplasty registries, but surgeon-stratified reports of endoprosthetic survival are very rare. The aim of the presented single hospital cohort analysis of this implant was to determine Link Lubinus SP II survival rates 10/15/20/25/30 years after the primary implantation and to find out whether endoprosthesis survival depended on patients' age, gender, operated side, implanted femoral head diameter, and the operating surgeon. METHODS: The study included 2943 consecutive primary Link Lubinus SP II hip endoprostheses implanted at the University Medical Centre Ljubljana, Department of Orthopaedic Surgery (Ljubljana, Slovenia) between January 1, 1985, and December 31, 2018. Kaplan-Meier analysis and Cox regression were performed after minimum two and maximum 30 years of follow-up. RESULTS: At 10/15/20/25/30 years after implantation, the estimated cumulative proportion of revision-free surviving Link Lubinus SP II total hip endoprostheses was 94/90/88/87/87% and the cumulative proportion with unremoved endoprosthetic components was 96/93/90/89/89%, respectively. Higher patient's age at operation was associated with lower risk of subsequent implant removal (hazard ratio 0.97 for each additional year of age; 95% confidence interval 0.95-0.99; p = 0.00), while the patient's gender, the implanted femoral head diameter, and the operating surgeon had no significant impact on implant survival. CONCLUSION: The study presents the largest published Link Lubinus SP II total hip arthroplasty cohort from a single non-developmental hospital with 26,981 component-years of observation. The findings highlight excellent outcomes of this implant in the elderly population, regardless of performance variability between surgeons.

Evaluation and interpretation of prosthetic joint infection diagnostic investigations.

BACKGROUND: Total joint arthroplasty (TJA) is considered one of the most successful surgical procedures ever developed. It can successfully provide pain relief, restore joint function, and improve mobility and quality of life. Prosthetic joint infection (PJI) presents with a wide variety and severity of signs and symptoms. It remains a major threat to the outcome of TJA procedures and usually necessitates surgical intervention and prolonged courses of antibiotics. Inappropriate treatment of an unrecognized PJI usually ends with unacceptable and sometimes catastrophic results. THE AIM: The understanding and evaluation of diagnostic investigations are extremely important to properly diagnose PJI, including frequently unrecognized low-grade infections, and to provide healthcare professionals with needed information for the care of patients affected by this condition. This article aims to review most of the methods available in PJI diagnostics, to emphasize the strengths and the weaknesses of each of them, and to provide a guideline on how to select the surgical treatment strategy based on the level of diagnostic certainty during the evaluation period. To safely accomplish this, it is crucial to be aware of the limitations of each diagnostic modality. THE FOCUS: The emphasis will be on the use and interpretation of the core criteria for PJI diagnosis, including the pathognomonic sinus tract communicating with the implant, purulent synovial fluid, inflammation in the periprosthetic tissue, cell count with differential, microbial growth in the synovial fluid culture, tissue sample cultures, and sonication samples.

Surgeon-stratified cohort analysis of 1976 cementless Zweymüller total hip arthroplasties from a single hospital with 23,255 component years of follow-up.

INTRODUCTION: The third-generation Zweymüller hip endoprosthesis has been used for decades with excellent results in arthroplasty registries, but surgeon-stratified reports on this implant are still scarce. The aim of the presented single-hospital cohort analysis of the third-generation Endoplus-Zweymüller primary total hip arthroplasty was to determine implant survival rates until the first revision/removal at 10/15/20/25 years after implantation and to find out whether implant survival depended on the operating surgeon, patient's age and gender, operated side (right/left), season of the year and the set of implanted components (SL-PLUS femur, BICON-PLUS acetabulum or both components). MATERIALS AND METHODS: The retrospective observational cohort study included 1976 consecutive patients with primary BICON/SL-PLUS Zweymüller hip endoprosthesis implanted at the same operating theater block of the University Medical Centre Ljubljana, Department of Orthopaedic Surgery (Ljubljana, Slovenia) between January 1, 1993 and May 1, 2014. Survival analyses were performed with the Kaplan-Meier method and the Cox regression analysis after minimum 5 and maximum 26 years of follow-up. RESULTS: At 10/15/20/25 years after implantation, the cumulative proportion of revision-free surviving Zweymüller total hip endoprostheses was 92/90/85/81% and the cumulative proportion with unremoved immobile components was 93/91/87/84%, respectively. After adjustment for age, gender and operated side, less experienced surgeons (odds ratios 2.34-5.00), season of the year at primary implantation (spring vs. winter odds ratio 1.74) and the use of BICON-PLUS acetabulum with femoral stem from another manufacturer (odds ratio 2.23) were significant risk factors of worse implant survival. CONCLUSIONS: The study presents the largest published third-generation Zweymüller BICON/SL-PLUS total hip arthroplasty cohort from a single non-developmental hospital with 23,255 component years of observation. Study findings indicate the impact of environmental factors at primary implantation and variability between different surgeons on the long-term implant survival.

The mechanism of NLRP3 inflammasome initiation: Trimerization but not dimerization of the NLRP3 pyrin domain induces robust activation of IL-1ß.

NLRP3 inflammasome is a multiprotein platform for the activation of caspase-1. Despite the increasing number of reports linking NLRP3 inflammasome to a variety of diseases, the mechanism behind the NLRP3 activation remains elusive, especially in terms of the early stages which are critical to the NLRP3 inflammasome assembly. In the present study we aimed to determine the minimal oligomerization state required for the NLRP3 inflammasome activation. For this purpose, NLRP3 pyrin domain (NLRP3PYD) was fused to various dimerization and trimerization domains. The constructs were expressed under the inducible promoter in mouse macrophages lacking endogenous NLRP3. Dimerization of the NLRP3PYD either in parallel or in antiparallel orientation was insufficient for the inflammasome activation. Trimerization of the NLRP3PYD with the foldon domain, however, induced pyroptosis and robust IL-1ß maturation, which was caspase-1 dependent. Interestingly, foldon-induced constitutive activation is resistant to inhibition with NLRP3-specific inhibitor MCC950 and does not lead to ASC speck formation. Although we cannot exclude that wild-type NLRP3 forms higher oligomer species similar to NLRP1 or NLRC4, our results clearly demonstrate that efficient IL-1ß response can be achieved by the induced trimerization of the NLRP3PYD domain.