Total cost of surgical site infection in the two years following primary knee replacement surgery

Objective:

The disease burden of surgical site infection (SSI) following total knee (TKA) replacement is considerable and is expected to grow with increased demand for the procedure. Diagnosing and treating SSI utilizes both inpatient and outpatient services, and the timing of diagnosis can affect health service requirements. The purpose of this study was to estimate the health system costs of infection and to compare them across time-to-diagnosis categories.

Methods:

Administrative data from 2005–2016 were used to identify cases diagnosed with SSI up to 1 year following primary TKA. Uninfected controls were selected matched on age, sex and comorbidities. Costs and utilization were measured over the 2-year period following surgery using hospital and out-of-hospital data. Costs and utilization were compared for those diagnosed within 30, 90, 180, and 365 days. A subsample of cases and controls without comorbidities were also compared.

Results:

We identified 238 SSI cases over the study period. On average, SSI cases cost 8 times more than noninfected controls over the 2-year follow-up period (CaD$41,938 [US$29,965] vs CaD$5,158 [US$3,685]) for a net difference of CaD$36,780 (US$26,279). The case-to-control ratio for costs was lowest for those diagnosed within 30 days compared to those diagnosed later. When only patients without comorbidities were included, costs were >7 times higher.

Conclusion:

Our results suggest that considerable costs result from SSI following TKA and that those costs vary depending on the time of diagnosis. A 2-year follow-up period provided a more complete estimate of cost and utilization.

Measuring Surgical Site Infection From Linked Administrative Data Following Hip and Knee Replacement

BACKGROUND

Surgical site infections (SSIs) in hip and knee arthroplasty are increasing internationally. Current trends in SSI monitoring use single source administrative databases with data collection points commonly at 30 or 90 days. We hypothesize that SSI rates are being under-reported due to methodological biases.

METHODS

Data from multiple administrative data sets were contrasted and compared to look at the 90-day SSI rates for hip and knee arthroplasty in a single province from 2001 to 2015. SSI rates were calculated over time by year, and the differences in infection rates between single and multiple administrative data sets were calculated as an estimate of under reporting rates of SSIs. Days until diagnosis was measured for those diagnosed with an infection within 1 year.

RESULTS

Combining administrative data sets indicates that hospital-based data underestimate SSI rates by 0.44 (P < .0001) of a percentage point over all years, a clinically significant result given the overall infection rate of 2.2% over the period. Less than 50% of hip and knee arthroplasty was recorded as infected by 30 days and approximately 75% of cases were recorded as infected by 90 days.

CONCLUSION

Single source administrative data sets and short follow-up periods underestimate SSI rates. Administrative data sets should be combined and a minimum follow-up period of 90 days should be used to more accurately track SSI rates in hip and knee arthroplasty.

Current preoperative antisepsis in neurosurgery: an example of the challenges in implementing evidence-based medicine to surgical practice

INTRODUCTION

Surgical site infection is associated with significant morbidity and mortality. Effective preoperative skin decolonisation is an important preventative strategy. The National Institute for Health and Care Excellence clinical guidelines recommend decolonisation using chlorhexidine gluconate (CHG) or povidone iodine (PVI). Current evidence indicates that CHG is more effective, while the combination of CHG and PVI is greater still. This study describes current practice among neurosurgeons in the UK, including differences between trainees and consultants, to review compliance with the latest evidence.

MATERIALS AND METHODS

A Society of British Neurosurgical Surgeons approved national, multicentre questionnaire was circulated online. A total of 74 complete responses were obtained from 27 trainees and 47 consultants, representing 28 of 37 neurosurgical centres.

RESULTS

Of the total responding centres, 36 (49%) used a single agent and 38 (51%) used a dual-agent preparation. One respondent used Tisept®. Seventy (95%) used alcohol in some form and none used aqueous CHG. Trainees were more likely to use a dual-agent preparation (P = 0.025). Forty-seven (63%) prepared the skin three or more times, with trainees preparing the skin more times than consultants (P = 0.002).

CONCLUSION

Neurosurgical practice adheres to national clinical guidelines but not the latest evidence from the literature. Given the weighting placed on randomised controlled trials, such a trial may be required to standardise practice that is likely to reduce surgical site infection.

Periprosthetic Infection following Primary Hip and Knee Arthroplasty: The Impact of Limiting the Postoperative Surveillance Period

BACKGROUND

Hip and knee arthroplasty infections are associated with considerable healthcare costs. The merits of reducing the postoperative surveillance period from 1 year to 90 days have been debated.

OBJECTIVES

To report the first pan-Canadian hip and knee periprosthetic joint infection (PJI) rates and to describe the implications of a shorter (90-day) postoperative surveillance period.

METHODS

Prospective surveillance for infection following hip and knee arthroplasty was conducted by hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP) using standard surveillance definitions.

RESULTS

Overall hip and knee PJI rates were 1.64 and 1.52 per 100 procedures, respectively. Deep incisional and organ-space hip and knee PJI rates were 0.96 and 0.71, respectively. In total, 93% of hip PJIs and 92% of knee PJIs were identified within 90 days, with a median time to detection of 21 days. However, 11%–16% of deep incisional and organ-space infections were not detected within 90 days. This rate was reduced to 3%–4% at 180 days post procedure. Anaerobic and polymicrobial infections had the shortest median time from procedure to detection (17 and 18 days, respectively) compared with infections due to other microorganisms, including Staphylococcus aureus.

CONCLUSIONS

PJI rates were similar to those reported elsewhere, although differences in national surveillance systems limit direct comparisons. Our results suggest that a postoperative surveillance period of 90 days will detect the majority of PJIs; however, up to 16% of deep incisional and organ-space infections may be missed. Extending the surveillance period to 180 days could allow for a better estimate of disease burden.

Infect Control Hosp Epidemiol 2017;38:147–153

Systematic Review and Meta-Analysis of Preoperative Antisepsis with Combination Chlorhexidine and Povidone-Iodine

Importance  Effective preoperative antisepsis is recognized to prevent surgical site infection (SSI), although the definitive method is unclear. Many have compared chlorhexidine (CHG) with povidone-iodine (PVI), but there is emerging evidence for combination usage. Objective  To conduct a systematic review and meta-analysis to evaluate if combination skin preparation (1) reduces colonization at the operative site and (2) prevents SSI compared with single-agent use. Data Sources  A literature search of MEDLINE, Embase, and Cochrane Database of Clinical Trials was performed. Study Selection  Comparative, human trials considering the combination use of CHG and PVI, as preoperative antisepsis, to single-agent CHG or PVI use were included. Studies were excluded from meta-analysis if the use or absence of alcohol was inconsistent between study arms. Data Extraction and Synthesis  The study was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Main Outcomes and Measures  The primary outcome for meta-analysis was surgical site infection. The secondary outcome was colonization at the operative site. Results  Eighteen publications with a combination of CHG and PVI use were identified. Of these, 12/14 inferred promise for combination usage, including four trials eligible for meta-analysis. Only one trial reported SSI as its outcome. The remaining three considered bacterial colonization. Combination preparation had a pooled odds ratio for complete decolonization of 5.62 (95% confidence interval 3.2 to 9.7, p  < 0.00001). There was no evidence of heterogeneity (Cochran's Q 2.1, 2 df , p  = 0.35). Conclusions and Relevance  There is emerging, albeit low-quality, evidence in favor of combination CHG and PVI preoperative antisepsis. Further rigorous investigation is indicated.

Implementation of a care bundle and evaluation of risk factors for surgical site infection in cranial neurosurgery

OBJECTIVES

Surgical site infection [SSI] increases mortality, morbidity and length of hospital stay. Peri-operative 'care bundles' have reduced SSI in some fields of surgery. The aim of this study was to determine the impact of bundle compliance on SSI in patients undergoing a craniotomy.

PATIENTS AND METHOD

Cohort study of patients [N=1253] undergoing a craniotomy over 17 months at a single centre. SSI was defined as arising within 30days of operation or 1year where an implant(s) remains. 'Bundle compliance' required administration of antibiotics <60min of induction, maintenance of intraoperative blood sugar (BM) <11mmol and temperature at >36°C. SSI incidence was compared between bundle compliant and non-compliant groups. Case mix adjustment was performed using binary logistic regression.

RESULTS

Over the study period, 1253 procedures were carried out and 66 patients (5.3%) developed a SSI. The majority (38, 57.6%) of these cultured Staphyloccoccus species. Only the use of an implant was found to be an independent risk factor for SSI [AOR 2.5, p<0.005, 95%CI 1.4, 4.3]. The use of the bundle did not reduce the occurrence of SSI.

CONCLUSIONS

An evidence-based bundle did not reduce SSI in this neurosurgical series. The use of an implant was an independent risk factor of its occurrence.