Maria C.S. Inacio

Risk factors associated with deep surgical site infections after primary total knee arthroplasty: an analysis of 56,216 knees.

BACKGROUND Deep surgical site infection following total knee arthroplasty is a devastating complication. Patient and surgical risk factors for this complication have not been thoroughly examined. The purpose of this study was to evaluate risk factors associated with deep surgical site infection following total knee arthroplasty in a large U.S. integrated health-care system. METHODS A retrospective review of a prospectively followed cohort of primary total knee arthroplasties recorded in a total joint replacement registry from 2001 to 2009 was conducted. Records were screened for deep surgical site infection with use of a validated algorithm, and the results were adjudicated by chart review. Patient factors, surgical factors, and surgeon and hospital characteristics were identified with use of the total joint replacement registry. Cox regression models were used to assess risk factors associated with deep surgical site infection. RESULTS A total of 56,216 total knee arthroplasties were identified; 63.0% were done in women, the average age of the patients was 67.4 years (standard deviation [SD] = 9.6), and the average body mass index (BMI) was 32 kg/m2 (SD = 6). The incidence of deep surgical site infection was 0.72% (404/56,216). In a fully adjusted model, patient factors associated with deep surgical site infection included a BMI of ≥35 (hazard ratio [HR] = 1.47), diabetes mellitus (HR = 1.28), male sex (HR = 1.89), an American Society of Anesthesiologists (ASA) score of ≥3 (HR = 1.65), a diagnosis of osteonecrosis (HR = 3.65), and a diagnosis of posttraumatic arthritis (HR = 3.23). Hispanic race was protective (HR = 0.69). Protective surgical factors included use of antibiotic irrigation (HR = 0.67), a bilateral procedure (HR = 0.51), and a lower annual hospital volume (HR = 0.33). Surgical risk factors included quadriceps-release exposure (HR = 4.76) and the use of antibiotic-laden cement (HR = 1.53). In a subanalysis, operative time was a risk factor, with a 9% increased risk per fifteen-minute increment. CONCLUSIONS Use of a comprehensive infection surveillance system, combined with a total joint replacement registry, identified patient and surgical factors associated with infection following total knee arthroplasty in a large sample. High-risk patients should be counseled, and modifiable clinical conditions should be optimized. Use of antibiotic irrigation should be encouraged, but antibiotic-laden cement may not be useful. LEVEL OF EVIDENCE Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Risk factors associated with surgical site infection in 30 491 primary total hip replacements

We examined patient and surgical factors associated with deep surgical site infection (SSI) following total hip replacement (THR) in a large integrated healthcare system. A retrospective review of a cohort of primary THRs performed between 2001 and 2009 was conducted. Patient characteristics, surgical details, surgeon and hospital volumes, and SSIs were identified using the Kaiser Permanente Total Joint Replacement Registry (TJRR). Proportional-hazard regression models were used to assess risk factors for SSI. The study cohort consisted of 30,491 THRs, of which 17,474 (57%) were performed on women. The mean age of the patients in the whole series was 65.5 years (13 to 97; SD 11.8) and the mean body mass index was 29.3 kg/m(2) (15 to 67; SD 5.9). The incidence of SSI was 0.51% (155 of 30,491). Patient factors associated with SSI included female gender, obesity, and American Society of Anesthesiologists (ASA) score ≥ 3. Age, diagnosis, diabetes and race were not associated with SSI. The only surgical factor associated with SSI was a bilateral procedure. Surgeon and hospital volumes, use of antibiotic-laden cement, fixation method, laminar flow, body exhaust suits, surgical approach and fellowship training were not associated with risk of SSI. A comprehensive infection surveillance system, combined with a TJRR, identified patient and surgical factors associated with SSI. Obesity and chronic medical conditions should be addressed prior to THR. The finding of increased SSI risk with bilateral THR requires further investigation.

Does Discharge Disposition After Primary Total Joint Arthroplasty Affect Readmission Rates

We reviewed 90-day readmission rates for 9150 patients with a primary total hip or knee arthroplasty performed between April 2001 and December 2004. Patients with an American Society of Anesthesiologists score of 3 or greater or with perioperative complications were excluded. We correlated the readmission rate with discharge disposition to either skilled nursing facilities (SNFs) or Home. Of the 9150 patients identified, 1447 were discharged to an SNF. After statistically adjusting for sex, age and American Society of Anesthesiologists scores, total hip arthroplasty and total knee arthroplasty patients discharged to SNFs had higher odds of hospital readmission within 90 days of surgery than those discharged home (total hip arthroplasty: odds ratio = 1.9; 95% confidence interval, 1.2-3.2; P = .008; total knee arthroplasty: odds ratio = 1.6; 95% confidence interval, 1.1-2.4; P = .01). Healthy patients discharged to SNFs after primary total joint arthroplasty need to be followed closely for complications.

A Prospective Study of 80,000 Total Joint and 5000 Anterior Cruciate Ligament Reconstruction Procedures in a Community-Based Registry in the United States

Health-care costs in the United States have increased substantially over time. From 1980 to 2007, the percentage of gross national product spent on health care has increased from 8.8% to 16%1. Total joint replacement is one of the most costly diagnosis-related groups, with >600,000 procedures performed each year in the United States2,3. The demand for total joint replacement is expected to increase in the United States as a result of advances in medical technology, an increased prevalence of obesity, and an increasing aging population2,4. By 2030, annual volumes are projected to increase by 673% for primary total knee arthroplasty and by 174% for primary total hip arthroplasty4. The demand for revision total knee and total hip arthroplasty is also projected to increase by 601% and 137%, respectively. Total knee and total hip arthroplasty costs are also expected to increase dramatically, with annual hospital charges estimated to reach

Knee replacement: epidemiology, outcomes, and trends in Southern California 17,080 replacements from 1995 through 2004

40.8 billion for primary total knee arthroplasty and

Analysis of 16,192 Anterior Cruciate Ligament Reconstructions From a Community-Based Registry

17.4 billion for primary total knee arthroplasty by 20155. Similar increases in cost are projected for revision total knee and total hip arthroplasty. Wilson et al. estimated that by 2030, total knee arthroplasty and total hip arthroplasty will cost Medicare over

Comparison of the Norwegian Knee Arthroplasty Register and a United States Arthroplasty Registry

50 billion6. In addition to increases in demand and cost, recent concerns about metal-on-metal bearing surfaces7 and recent implant recalls and advisories have emphasized the need to monitor total joint outcomes nationwide. The identification of procedures and implants associated with higher revision rates could prevent revision procedures, improving care and addressing the increased cost and demand associated with this procedure. Joint registries provide one potential solution for reducing total joint replacement implant variation and revision rates. The Swedish Hip Register8-11 has demonstrated the effectiveness …

Are Meniscus and Cartilage Injuries Related to Time to Anterior Cruciate Ligament Reconstruction

Background and purpose There are limited popula-tion-based data on utilization, outcomes, and trends in total knee arthroplasty (TKA). The purpose of this study was to examine TKA utilization and short-term outcomes in a pre-paid health maintenance organization (HMO), and to determine whether rates and revision burden changed over time. We also studied whether this population is representative of the general population in California and in the United States. Methods Using hospital utilization and membership databases from 1995 through 2004, we calculated incidence rates (IRs) of primary and revision TKA for every 10,000 health plan members. The demographics of the HMO population were compared to published census data from California and the United States. Results The age and sex distributions of the study population were similar to those of the general population in California and the United States. 15,943 primary TKAs and 1,137 revision TKAs were performed during the 10-year period. Patients below the age of 65 accounted for one-third of all primary replacements and one-third of all revision replacements. IRs of primary TKAs increased from 6.3 per 10,000 in 1995 to 11.0 per 10,000 in 2004, at a rate of 5% per year (p<0.001). IRs of revision TKAs increased from 0.41 per 10,000 in 1995 to 0.74 per 10,000 in 2004 (p=0.4). Revision burden remained stable over the 10-year observation period. Surgical complications were higher in revision TKA than in primary TKA (10% vs. 7.7%; p=0.007). 90day complication rates for primary and revision TKA including death were 0.3% and 0.6% (p=0.1) and for pulmonary embolism 0.5% and 0.4% (p=0.6). 90day re-admission rates for primary and revision TKA including infection were 0.5% and 4.2% (p<0.001), for myocardial infarction 0.1% each, and for pneumonia 0.2% and 0.4% (p=0.08). Interpretation The incidence of primary and revision TKA increased between 1995 and 2005. The rates of postoperative complications were low. Comparisons of the study population and the underlying general populations of interest indicate that this population can be used to predict the incidences and outcomes of TKA in the general population of California and of the United States as a whole.

The kaiser permanente national total joint replacement registry.

Background: Orthopaedic registries have shown value in tracking and surveillance of patients, implants, and outcomes associated with procedures. No current anterior cruciate ligament reconstruction registry (ACLRR) exists in the United States. Purpose: To describe the current cohort captured by an institutional ACLRR and describe the outcomes observed in the registered patients and how findings from the ACLRR are disseminated. Study Design: Cohort study; Level of evidence, 2. Methods: The anterior cruciate ligament reconstructions (ACLRs) registered between February 2005 and September 2011 by 244 surgeons in 48 medical centers were evaluated. The ACLRR collected data intra- and postoperatively using paper forms and electronic medical records. The ACLRR cohort was longitudinally followed and outcomes were prospectively ascertained. Outcomes (ie, revisions, subsequent operations, venous thromboembolism, and surgical site infections) were adjudicated via chart review. Descriptive statistics are used to describe the cohort and Kaplan-Meier curves to evaluate survival. Results: During the study period, 16,192 ACLRs (15,101 primary and 1091 revisions) with a median follow-up of 1.6 years (interquartile range, 0.7-2.8 years) were registered. Male patients received 64% of both primary and revision ACLRs. The mean age at surgery was 29.5 years (SD, 11.4 years) for primary and revision reconstructions. Cartilage injuries were noted in 25.2% of primary and 37.5% of revision ACLRs, and meniscal injuries were identified in 60.8% and 53.2%, respectively. Autografts were used in 57.6% of primary ACLRs and 20.9% of revisions. Allografts were used in 42.4% of primaries and 78.8% of revisions. In primary ACLR, the most common femoral and tibial fixation types were interference screws (42.2% and 79.7%, respectively). Fixation type distribution was nearly identical in primaries and revisions. Of the primary ACLRs, 3.7% had subsequent operations on the same knee and 1.7% on the contralateral knee. Deep surgical site infection developed in 0.3% of primaries and 0.8% of revisions. Symptomatic deep vein thromboses were seen in 0.2% of both primaries and revisions. The overall revision rate was 1.7%. Lower rates of graft survival were identified in younger patients and those with allografts. Conclusion: Large, community-based ACLRRs are useful in informing participating surgeons of current treatment practices, prevalence of concurrent injuries, and outcomes associated with the procedures. Information from the ACLRR can be used to develop interactive patient and surgeon tools that can be used to optimize patient care.

The Kaiser Permanente Implant Registries: Effect on Patient Safety, Quality Improvement, Cost Effectiveness, and Research Opportunities

Several national total joint arthroplasty registries exist outside of the United States (U.S.) and have been used to compare rates and outcomes of total knee arthroplasty. Within the U.S., regional arthroplasty registries provide an opportunity to compare U.S. practices and outcomes with those of other countries. The purpose of this study was to compare the demographics, choice of implants, techniques, and outcomes of total knee arthroplasties in Norway to those from a large, U.S. integrated health-care system and to determine the feasibility of using aggregate-level data for international registry comparisons. The study sample consisted of 25,004 primary total knee arthroplasties performed in Norway and 56,208 from the Kaiser Permanente health-care system. Summary-level data were used to compare the two cohorts. At the time of the seven-year follow-up, the cumulative survival of the total knee prosthesis was 94.8% for the arthroplasties performed in Norway and 96.3% for those performed at Kaiser Permanente. The primary reasons for revision arthroplasty included infection, instability, pain, and aseptic loosening. Patient characteristics, selection of implants, surgical techniques, and outcomes differed between the cohorts. Harmonization of data elements and definitions is necessary for future international research.