Effect of a national infection control programme in Sweden on prosthetic joint infection incidence following primary total hip arthroplasty: a cohort study.

OBJECTIVES: Prosthetic joint infection (PJI) is a serious complication following total hip arthroplasty (THA) entailing increased mortality, decreased quality of life and high healthcare costs.The primary aim was to investigate whether the national project: Prosthesis Related Infections Shall be Stopped (PRISS) reduced PJI incidence after primary THA; the secondary aim was to evaluate other possible benefits of PRISS, such as shorter time to diagnosis. DESIGN: Cohort study. SETTING: In 2009, a nationwide, multidisciplinary infection control programme was launched in Sweden, PRISS, which aimed to reduce the PJI burden by 50%. PARTICIPANTS: We obtained data on patients undergoing primary THA from the Swedish Arthroplasty Registry 2012-2014, (n=45 723 patients, 49 946 THAs). Using personal identity numbers, this cohort was matched with the Swedish Prescribed Drug Registry. Medical records of patients with ≥4 weeks' antibiotic consumption were reviewed to verify PJI diagnosis (n=2240, 2569 THAs). RESULTS: The cumulative incidence of PJI following the PRISS Project was 1.2% (95% CI 1.1% to 1.3%) as compared with 0.9% (95% CI 0.8% to 1.0%) before. Cox regression models for the PJI incidence post-PRISS indicates there was no statistical significance difference versus pre-PRISS (HR 1.1 (95% CI 0.9 to 1.3)). There was similar time to PJI diagnosis after the PRISS Project 24 vs 23 days (p=0.5). CONCLUSIONS: Despite the comprehensive nationwide PRISS Project, Swedish PJI incidence was higher after the project and time to diagnosis remained unchanged. Factors contributing to PJI, such as increasing obesity, higher American Society of Anesthesiology class and more fractures as indications, explain the PJI increase among primary THA patients.

Associations between future health expectations and patient satisfaction after lumbar spine surgery: a longitudinal observational study of 9929 lumbar spine surgery procedures.

OBJECTIVE: This study aimed to investigate the associations between general health expectations and patient satisfaction with treatment for the two common spine surgery procedures diskectomy for lumbar disk herniation (LDH) and decompression for lumbar spinal stenosis (LSS). DESIGN: Register study with prospectively collected preoperative and 1-year postoperative data. SETTING: National outcome data from Swespine, the national Swedish spine register. PARTICIPANTS: A total of 9929 patients, aged between 20 and 85 years, who were self-reported non-smokers, and were operated between 2007 and 2016 for one-level LSS without degenerative spondylolisthesis, or one-level LDH, were identified in the national Swedish spine register (Swespine). We used SF-36 items 11c and 11d to assess future health expectations and present health perceptions. Satisfaction with treatment was assessed using the Swespine satisfaction item. INTERVENTIONS: One-level diskectomy for LDH or one-level decompression for LSS. PRIMARY OUTCOME MEASURES: Satisfaction with treatment. RESULTS: For LSS, the year 1 satisfaction ratio among patients with negative future health expectations preoperatively was 60% (95% CI 58% to 63%), while it was 75% (95% CI 73% to 76%) for patients with positive future health expectations preoperatively. The corresponding numbers for LDH were 73% (95% CI 71% to 75%) and 84% (95% CI 83% to 85%), respectively. CONCLUSIONS: Patients operated for the common lumbar spine diseases LSS or LDH, with negative future general health expectations, were significantly less satisfied with treatment than patients with positive expectations with regard to future general health. These findings are important for patients, and for the surgeons who counsel them, when surgery is a treatment option for LSS or LDH.

Properties of the EQ-5D-5L when prospective longitudinal data from 28,902 total hip arthroplasty procedures are applied to different European EQ-5D-5L value sets.

BACKGROUND: The purpose of this study was to evaluate the impact of using different country-specific value sets in EQ-5D-5L based outcome analyses. METHODS: We obtained data on patients surgically treated with total hip arthroplasty (THA) between 2017 and 2019 from the national Swedish Hip Arthroplasty Register. Preoperative and one-year postoperative data on a total of 28,902 procedures were available for analysis. The EQ-5D-5L health states were coded to the EQ-5D-5L preference indices using 13 European value sets. The EQ-5D-5L index distributions were then estimated with kernel density estimation. The change in EQ-5D-5L index before and one year after treatment was evaluated with the standardized response mean (SRM). The lifetime gain in quality-adjusted life years (QALYs) was estimated with a 3.5% annual QALY discount rate. FINDINGS: There was a marked variability in means and shapes of the resulting EQ-5D-5L index distributions. There were also considerable differences in the EQ-5D-5L index distribution shape before and after the treatment using the same value set. The effect sizes of one-year change (SRM) were similar for all value sets. However, the differences in estimated QALY gains were substantial. INTERPRETATION: The EQ-5D-5L index distributions varied considerably when a single large data set was applied to different European EQ-5D-5L value sets. The most pronounced differences were between the value sets based on experience-based valuation and the value sets based on hypothetical valuation. This illustrates that experience-based and hypothetical value sets are inherently different and also that QALY gains derived with different value sets are not comparable. Our findings are of importance in study planning since the results and conclusions of a study depend on the choice of value set. FUNDING: None.

What Are the Long-term Outcomes of Mortality, Quality of Life, and Hip Function after Prosthetic Joint Infection of the Hip? A 10-year Follow-up from Sweden.

BACKGROUND: Prosthetic joint infection (PJI) is a complication after arthroplasty that negatively affects patient health. However, prior reports have not addressed the long-term consequences of hip PJI in terms of patient mortality, quality of life, and hip function. QUESTIONS/PURPOSES: At a minimum of 10 years after PJI in patients undergoing primary THA, in the context of several large, national databases in Sweden, we asked: (1) Is mortality increased for patients with PJI after THA compared with patients with a noninfected THA? (2) Does PJI of the hip have a negative influence on quality of life as measured by the Euro-QoL-5D-5L (EQ-5D-5L), ambulatory aids, residential status, and hip function as measured by the Oxford Hip Score (OHS)? (3) Which factors are associated with poor patient-reported outcome measures (PROMs) for patients with PJI after primary THA? METHODS: This study included 442 patients with a PJI after primary THA, from a previously published national study, including all patients with a THA performed from 2005 to 2008 in Sweden (n = 45,570) recruited from the Swedish Hip Arthroplasty Registry (SHAR). Possible deep PJIs were identified in the Swedish Dispensed Drug Registry and verified by review of medical records. Mortality in patients with PJI was compared with the remaining cohort of 45,128 patients undergoing primary THA who did not have PJI. Mortality data were retrieved from the SHAR, which in turn is updated daily from the population registry. A subgroup analysis of patients who underwent primary THA in 2008 was performed to adjust for the effect of comorbidities on mortality, as American Society of Anesthesiologists (ASA) scores became available in the SHAR at that time. For the PROM analysis, we identified three controls matched by age, gender, indication for surgery, and year of operation to each living PJI patient. A questionnaire including EQ-5D-5L, ambulatory aids, residential status, and OHS was collected from patients with PJI and controls at a mean of 11 years from the primary procedure. Apart from age and gender, we analyzed reoperation data (such as number of reoperations and surgical approach) and final prosthesis in situ to explore possible factors associated with poor PROM results. RESULTS: After controlling for differences in sex, age, and indication for surgery, we found the all-cause 10-year mortality higher for patients with PJI (45%) compared with patients undergoing THA without PJI (29%) (odds ratio 1.4 [95% CI 1.2 to 1.6]; p < 0.001). The questionnaire, with a minimum of 10 years of follow-up, revealed a lower EQ-5D-5L index score (0.83 versus 0.94, -0.13 [95% CI -0.18 to -0.08; p < 0.001]), greater proportion of assisted living (21% versus 12%, OR 2.0 [95% CI 1.2 to 3.3]; p = 0.01), greater need of ambulatory aids (65% versus 42%, OR 3.1 [95% 2.1 to 4.8]; p < 0.001), and a lower OHS score (36 versus 44, -5.9 [-7.7 to -4.0]; p < 0.001) for patients with PJI than for matched controls. Factors associated with lower OHS score for patients with PJI were three or more reoperations (-8.0 [95% CI -13.0 to -3.2]; p = 0.01) and a direct lateral approach used at revision surgery compared with a posterior approach (-4.3 [95% CI -7.7 to -0.9]; p = 0.01). CONCLUSION: In this study, we found that PJI after THA has a negative impact on mortality, long-term health-related quality of life, and hip function. Furthermore, the subgroup analysis showed that modifiable factors such as the number of reoperations and surgical approach are associated with poorer hip function. This emphasizes the importance of prompt, proper initial treatment to reduce repeated surgery to minimize the negative long-term effects of hip PJI. LEVEL OF EVIDENCE: Level III, therapeutic study.

Staphylococcus argenteus as an etiological agent of prosthetic hip joint infection: a case presentation.

This report presents a case of prosthetic hip infection caused by Staphylococcus argenteus, a potentially overlooked etiology of prosthetic joint infections (PJIs). Whole-genome sequencing showed that the S. argenteus isolate was an ST2250 and clustered within other CC2250 isolates, the largest clonal group of S. argenteus. This sequence type is prevalent and may be associated with invasive infections. The present isolate was phenotypically fully susceptible to all tested antimicrobial agents and genome analysis did not detect any resistance genes, nor were any staphylococcal cassette chromosome residues detected. Despite initial appropriate management with debridement and biofilm-active antibiotics, the outcome was unfavorable with recurrence and a persistent infection treated with suppressive antibiotics. Regarding the repertoire of genomic traits for virulence in S. argenteus, PJIs caused by this bacterium should be treated accordingly as Staphylococcus aureus PJIs.

Genomic characterization and outcome of prosthetic joint infections caused by Staphylococcus aureus.

Staphylococcus aureus is a commensal colonizing the skin and mucous membranes. It can also act as a pathogen, and is the most common microorganism isolated from prosthetic joint infections (PJIs). The aim of this study was to explore the genomic relatedness between commensal and PJI S. aureus strains as well as microbial traits and host-related risk factors for treatment failure. Whole-genome sequencing (WGS) was performed on S. aureus isolates obtained from PJIs (n = 100) and control isolates from nares (n = 101). Corresponding clinical data for the PJI patients were extracted from medical records. No PJI-specific clusters were found in the WGS phylogeny, and the distribution of the various clonal complexes and prevalence of virulence genes among isolates from PJIs and nares was almost equal. Isolates from patients with treatment success and failure were genetically very similar, while the presence of an antibiotic-resistant phenotype and the use of non-biofilm-active antimicrobial treatment were both associated with failure.In conclusion, commensal and PJI isolates of S. aureus in arthroplasty patients were genetically indistinguishable, suggesting that commensal S. aureus clones are capable of causing PJIs. Furthermore, no association between genetic traits and outcome could be demonstrated, stressing the importance of patient-related factors in the treatment of S. aureus PJIs.

Propionibacterium avidum as an Etiological Agent of Prosthetic Hip Joint Infection.

Propionibacterium acnes is well-established as a possible etiologic agent of prosthetic joint infections (PJIs). Other Propionibacterium spp. have occasionally been described as a cause of PJIs, but this has not previously been the case for P. avidum despite its capacity to form biofilm. We describe two patients with prosthetic hip joint infections caused by P. avidum. Both patients were primarily operated with an anteriorly curved skin incision close to the skin crease of the groin, and both were obese. Initial treatment was performed according to the DAIR procedure (debridement, antibiotics, and implant retention). In case 1, the outcome was successful, but in case 2, a loosening of the cup was present 18 months post debridement. The P. avidum isolate from case 1 and two isolates from case 2 (obtained 18 months apart) were selected for whole genome sequencing. The genome of P. avidum obtained from case 1 was approximately 60 kb larger than the genomes of the two isolates of case 2. These latter isolates were clonal with the exception of SNPs in the genome. All three strains possessed the gene cluster encoding exopolysaccharide synthesis. P. avidum has a pathogenic potential and the ability to cause clinically relevant infections, including abscess formation, in the presence of foreign bodies such as prosthetic joint components. Skin incision in close proximity to the groin or deep skin crease, such as the anteriorly curved skin incision approach, might pose a risk of PJIs by P. avidum, especially in obese patients.