Validation of reoperations due to infection in the Swedish Hip Arthroplasty Register

Periprosthetic Joint Infection After Total Knee Arthroplasty With or Without Antibiotic Bone Cement

Importance

Despite increased use of antibiotic-loaded bone cement (ALBC) in joint arthroplasty over recent decades, current evidence for prophylactic use of ALBC to reduce risk of periprosthetic joint infection (PJI) is insufficient.

Objective

To compare the rate of revision attributed to PJI following primary total knee arthroplasty (TKA) using ALBC vs plain bone cement.

Design, Setting, and Participants

This international cohort study used data from 14 national or regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, New Zealand, Norway, Romania, Sweden, Switzerland, the Netherlands, the UK, and the US. The study included primary TKAs for osteoarthritis registered from January 1, 2010, to December 31, 2020, and followed-up until December 31, 2021. Data analysis was performed from April to September 2023.

Exposure

Primary TKA with ALBC vs plain bone cement.

Main Outcomes and Measures

The primary outcome was risk of 1-year revision for PJI. Using a distributed data network analysis method, data were harmonized, and a cumulative revision rate was calculated (1 - Kaplan-Meier), and Cox regression analyses were performed within the 10 registries using both cement types. A meta-analysis was then performed to combine all aggregated data and evaluate the risk of 1-year revision for PJI and all causes.

Results

Among 2 168 924 TKAs included, 93% were performed with ALBC. Most TKAs were performed in female patients (59.5%) and patients aged 65 to 74 years (39.9%), fully cemented (92.2%), and in the 2015 to 2020 period (62.5%). All participating registries reported a cumulative 1-year revision rate for PJI of less than 1% following primary TKA with ALBC (range, 0.21%-0.80%) and with plain bone cement (range, 0.23%-0.70%). The meta-analyses based on adjusted Cox regression for 1 917 190 TKAs showed no statistically significant difference at 1 year in risk of revision for PJI (hazard rate ratio, 1.16; 95% CI, 0.89-1.52) or for all causes (hazard rate ratio, 1.12; 95% CI, 0.89-1.40) among TKAs performed with ALBC vs plain bone cement.

Conclusions and Relevance

In this study, the risk of revision for PJI was similar between ALBC and plain bone cement following primary TKA. Any additional costs of ALBC and its relative value in reducing revision risk should be considered in the context of the overall health care delivery system.

Enhancing the data capture of periprosthetic joint infections in the Danish Knee Arthroplasty Registry: validity assessment and incidence estimation

BACKGROUND AND PURPOSE

Revisions due to periprosthetic joint infection (PJI) are underestimated in national arthroplasty registries. Our primary objective was to assess the validity in the Danish Knee Arthroplasty Register (DKR) of revisions performed due to PJI against the Healthcare-Associated Infections Database (HAIBA). The secondary aim was to describe the cumulative incidences of revision due to PJI within 1 year of primary total knee arthroplasty (TKA) according to the DKR, HAIBA, and DKR/HAIBA combined.

METHODS

This longitudinal observational cohort study included 56,305 primary TKAs (2010-2018), reported in both the DKR and HAIBA. In the DKR, revision performed due to PJI was based on pre- and intraoperative assessment disclosed by the surgeon immediately after surgery. In HAIBA, PJI was identified from knee-related revision procedures coinciding with 2 biopsies with identical microbiological pathogens. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of revision due to PJI in the DKR (vs. HAIBA, within 1 year of TKA) with 95% confidence intervals (CI). Cumulative incidences were calculated using the Kaplan-Meier method.

RESULTS

The DKR's sensitivity for PJI revision was 58% (CI 53-62) and varied by TKA year (41%-68%) and prosthetic type (31% for monoblock; 63% for modular). The specificity was 99.8% (CI 99.7-99.8), PPV 64% (CI 62-72), and NPV 99.6% (CI 99.6-99.7). 80% of PJI cases not captured by the DKR were caused by non-reporting rather than misclassification. 33% of PJI cases in the DKR or HAIBA were culture-negative. Considering potential misclassifications, the best-case sensitivity was 64%. The cumulative incidences of PJI were 0.8% in the DKR, 0.9% in HAIBA, and 1.1% when combining data.

CONCLUSION

The sensitivity of revision due to PJI in the DKR was 58%. The cumulative incidence of PJI within 1 year after TKA was highest (1.1%) when combining the DKR and HAIBA, showing that incorporating microbiology data into arthroplasty registries can enhance PJI validity.

Validation of the Incidence of Reported Periprosthetic Joint Infections in Total Hip and Knee Arthroplasty in the Dutch Arthroplasty Register

BACKGROUND

Arthroplasty registers underreport the incidence of periprosthetic joint infections (PJIs). We validated the incidence of reported PJIs in total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) in the Dutch Arthroplasty Register (LROI) using data from the Dutch National Nosocomial Surveillance Network (PREZIES).

METHODS

All primary THAs and TKAs from the LROI and all primary THAs and TKAs performed in consenting hospitals from PREZIES between 2012 and 2018 were matched on date of birth, date of surgery, sex, hospital, and type of procedure (THA n = 91,208; TKA n = 80,304). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for PJIs registered in the LROI, using PREZIES as a reference.

RESULTS

The incidence of registered PJIs in THAs was 1.2% in PREZIES and 0.5% in the LROI. For TKAs, this was 0.7 and 0.4%, respectively. The PJIs in THAs in the LROI had a sensitivity of 0.32 (confidence interval [CI]: 0.29 to 0.35), specificity of 1.00 (CI: 1.00 to 1.00), PPV of 0.74 (CI: 0.70 to 0.78), and NPV of 0.99 (CI: 0.99 to 0.99). In TKAs, the sensitivity, specificity, PPV, and NPV were 0.38 (CI: 0.34 to 0.42), 1.00 (CI: 1.00 to 1.00), 0.65 (CI: 0.59 to 0.70), and 1.00 (CI: 1.00 to 1.00), respectively.

CONCLUSIONS

The LROI captures approximately one-third of the PJIs as revision within one year for infection or resection arthroplasty. The capture rate of PJIs can be improved by including all reoperations without component exchange and nonsurgical treatments with antibiotics only.

The Impact of Surgical Approach on 90-Day Prosthetic Joint Infection After Total Hip Replacement - A Population-Based, Propensity Score-Matched Cohort Study

BACKGROUND

Prosthetic joint infection (PJI) is a devastating complication of total hip arthroplasty (THA). This study aimed to determine if the anterior approach (AP) influenced the incidence of early PJI in THA compared to posterior approach (PP).

METHODS

Record linkage was performed between state-wide hospitalization data and a national joint replacement registry to identify unilateral THA performed via the AP or PP. Complete data on 12,605 AP and 25,569 PP THAs were obtained. Propensity score matching (PSM) was undertaken to match covariates between the approaches. Outcomes were the 90-day PJI hospital readmission rate(using narrow and broad definitions) and 90-day PJI revision rate (defined as component removal or exchange).

RESULTS

The raw PJI readmission rate for AP was lower than PP (0.8% versus 1.1%, respectively). In the PSM analysis, there was no statistically significant difference in PJI readmission rate between approaches using narrow or broad definition of PJI readmission. In terms of revision for infection, both methods showed AP had a significantly lower rate than PP, with an adjusted odds ratio (OR) of 0.47 (95% confidence interval (CI) 0.30, 0.75) for the 1:1 nearest neighbor method and 0.50 (95% CI 0.32, 0.77) for the subclassification method.

CONCLUSION

After addressing known confounders, there was no significant difference in the 90-day hospital readmission rate for hip PJI between approaches. There was a significantly reduced 90-day PJI revision rate for AP. The difference in revision may reflect differences in the surgical management of PJI between hip approaches rather than a difference in the underlying rate of infection.

Temporal trends in revision rate due to knee periprosthetic joint infection: a study of 115,120 cases from the Danish Knee Arthroplasty Register

BACKGROUND AND PURPOSE

We aimed to examine the temporal trends in periprosthetic joint infection (PJI) revision incidence after knee arthroplasty (KA) from 1997 through 2019.

PATIENTS AND METHODS

115,120 primary KA cases from the Danish Knee Arthroplasty Register were followed until the first PJI revision. We computed cumulative incidences and adjusted hazard ratios (aHRs) of PJI revision by calendar periods and several patient- and surgical-related risk factors. Results were analyzed from 0-3 months and from 3-12 months after KA.

RESULTS

The overall 1-year PJI revision incidence was 0.7%, increasing from 0.5% to 0.7% (1997 through 2019). The incidence of PJI revision within 3 months increased from 0.1% to 0.5% (1997 through 2019). The adjusted hazard ratio (aHR) within 1 year of primary KA was 5.1 comparing 2017-2019 with 2001-2004. The PJI revision incidence from 3-12 months of KA decreased from 0.4% to 0.2%, with an aHR of 0.5 for 2017-2019 vs. 2001-2004. Male sex, age 75-84 (vs. 65-74), and extreme obesity (vs. normal weight) were positively associated with the risk of PJI revision within 3 months, whereas only male sex was associated from 3-12 months. Partial knee arthroplasty (PKA) vs. total KA was associated with a lower risk of PJI revision both within 3 months and 3-12 months of KA.

CONCLUSION

We observed an increase in PJI revision within 3 months of KA, and a decrease in PJI revision incidence from 3-12 months from 1997 through 2019. The reasons for this observed time-trend are thought to be multifactorial. PKA was associated with a lower risk of PJI revision.

Increased mortality after total hip prosthetic joint infection is mainly caused by the comorbidities rather than the infection itself

BACKGROUND AND PURPOSE

Periprosthetic joint infection (PJI) is a feared complication of arthroplasty surgery. There is controversy as to whether PJI also correlates with increased mortality. Our aim was to investigate in a nationwide cohort if PJI is an independent risk factor for dying.

PATIENTS AND METHODS

We performed a retrospective cohort study based on data from the Swedish Hip Arthroplasty Register (SHAR). All patients with a revision THA performed between 1998 and 2017 were included. The outcome is mortality; exposure is PJI according to SHAR. The control group was study participants who underwent aseptic revision. Confounders were age, sex, diagnosis, and comorbidity according to the Elixhauser index. The outcome was analyzed with a Cox proportional hazards model.

RESULTS

4,943 PJI revisions and 12,529 non-infected revisions were included in the analysis. The median follow-up time was 4.1 years. In the PJI group, 1,972 patients died and in the control group, 4,512. The incidence rate ratio was 1.19 (95% confidence interval [CI] 1.13-1.25), the crude hazard ratio (HR) 1.19 (CI 1.13-1.25), and the adjusted HR 1.05 (CI 0.99-1.12) for the exposed versus the unexposed group. The strongest confounder was comorbidity.

CONCLUSION

The increased mortality risk after revision due to PJI is mainly caused by the comorbidity of the patient, rather than by the infection itself.

Incidence of periprosthetic joint infection after primary total hip arthroplasty is underestimated: a synthesis of meta-analysis and bibliometric analysis

The American Musculoskeletal Society updated the diagnostic criteria for periprosthetic joint infection (PJI) in 2011 and 2018. However, the overall incidence of PJI since the introduction of these new standards has not been assessed. In order to fill this knowledge gap, a single-group meta-analysis was conducted using articles obtained from several databases, focusing on the incidence of PJI after primary total hip arthroplasty (THA). Our study revealed a significant difference in the incidence of PJI reported by different national or regional databases. Moreover, most cases of PJI were found to be underestimated. This highlights the crucial need for standardized diagnostic criteria and monitoring methods to accurately identify and track cases of PJI. Furthermore, a bibliometric analysis was conducted to provide a comprehensive overview of the current state of research on PJI after THA. This analysis explored the most productive countries, organizations, journals, and individuals in this research area. Additionally, it identified the research trends and hotspots of the last decade, highlighting the advancements and areas of focus in this field. By conducting these analyses, the study aims to contribute to the understanding of PJI after THA and provide valuable insights for clinicians, researchers, and policymakers involved in the management of this condition.

Increasing risk of revision due to infection after primary total hip arthroplasty: results from the Nordic Arthroplasty Register Association

BACKGROUND AND PURPOSE

The incidence of periprosthetic joint infection after total hip arthroplasty (THA) may be increasing. We performed time-trend analyses of risk, rates, and timing of revision due to infection after primary THAs in the Nordic countries from the period 2004-2018.

PATIENTS AND METHODS

569,463 primary THAs reported to the Nordic Arthroplasty Register Association from 2004 to 2018 were studied. Absolute risk estimates were calculated by Kaplan-Meier and cumulative incidence function methods, whereas adjusted hazard ratios (aHR) were assessed by Cox regression with the first revision due to infection after primary THA as primary endpoint. In addition, we explored changes in the time span from primary THA to revision due to infection.

RESULTS

5,653 (1.0%) primary THAs were revised due to infection during a median follow-up time of 5.4 (IQR 2.5-8.9) years after surgery. Compared with the period 2004-2008, the aHRs for revision were 1.4 (95% confidence interval [CI] 1.3-1.5) for 2009-2013, and 1.9 (CI 1.7-2.0) for 2014-2018. The absolute 5-year rates of revision due to infection were 0.7% (CI 0.7-0.7), 1.0% (CI 0.9-1.0), and 1.2% (CI 1.2-1.3) for the 3 time periods respectively. We found changes in the time span from primary THA to revision due to infection. Compared with 2004-2008, the aHR for revision within 30 days after THA was 2.5 (CI 2.1-2.9) for 2009-2013, and 3.4 (CI 3.0-3.9) for 2013-2018. The aHR for revision within 31-90 days after THA was 1.5 (CI 1.3-1.9) for 2009-2013, and 2.5 (CI 2.1-3.0) for 2013-2018, compared with 2004-2008.

CONCLUSION

The risk of revision due to infection after primary THA almost doubled, both in absolute cumulative incidence and in relative risk, throughout the period 2004-2018. This increase was mainly due to an increased risk of revision within 90 days of THA. This may reflect a "true" increase (i.e., frailer patients or more use of uncemented implants) and/or an "apparent" increase (i.e., improved diagnostics, changed revision strategy, or completeness of reporting) in incidence of periprosthetic joint infection. It is not possible to disclose such changes in the present study, and this warrants further research.

High Risk for Persistent Peri-Prosthetic Infection and Amputation in Mega-Prosthesis Reconstruction

A peri-prosthetic joint infection is a feared complication after mega-prosthesis reconstruction of large bone defects. The current study investigates how patients operated with a mega-prosthesis due to sarcoma, metastasis, or trauma, are affected by a deep infection focusing on re-operations, risk for persistent infection, arthrodesis, or subsequent amputation. Time to infection, causative bacterial strains, mode of treatment and length of hospital stay are also reported. A total of 114 patients with 116 prostheses were evaluated, a median of 7.6 years (range 3.8-13.7) after surgery, of which 35 (30%) were re-operated due to a peri-prosthetic infection. Of the infected patients, the prosthesis was still in place in 51%, 37% were amputated, and 9% had an arthrodesis. The infection was persistent in 26% of the infected patients at follow-up. The mean total length of hospital stay was 68 (median 60) days and the mean number of reoperations was 8.9 (median 6.0). The mean length of antibiotic treatment was 340 days (median 183). Coagulase-negative staphylococci and Staphylococcus aureus were the most frequent bacterial agents isolated in deep cultures. No MRSA- or ESBL-producing Enterobacterales were found but vancomycin-resistant Enterococcus faecium was isolated in one patient. In summary, there is a high risk for peri-prosthetic infection in mega-prostheses, resulting in persistent infection or amputation relatively often.

Intraosseous Vancomycin in Total Hip Arthroplasty - Superior Tissue Concentrations and Improved Efficiency

BACKGROUND

Literature shows that intraosseous (IO) infusions are capable of providing increased local concentrations compared to those administered via intravenous (IV) access. Successes while using the technique for antibiotic prophylaxis administration in total knee arthroplasty (TKA) prompted consideration for use in total hip arthroplasty (THA) however; no study exists for the use of IO vancomycin in THA.

METHODS

This single-blinded randomized control trial was performed from December 2020 to May 2022. Twenty patients were randomized into one of two groups: IV vancomycin (15 mg/kg) given routinely, or IO vancomycin (500mg/100cc of NS) injected into the greater trochanter during incision. Serum vancomycin levels were collected at incision and closure. Soft tissue vancomycin levels were taken from the gluteus maximus (at start and end of case), and acetabular pulvinar tissue. Bone vancomycin levels were taken from the femoral head, acetabular reamings, and intramedullary bone. Adverse local/systemic reactions, 30-day and 90-day complications were also tracked.

RESULTS

A statistically significant reduction in serum vancomycin levels was seen when comparing IO to IV vancomycin at both the start and end of the procedure. All local tissue samples had higher concentrations of vancomycin in the IO group. Statistically significant increases were present within the acetabular bone reamings, and approached significance in intramedullary femoral bone.

CONCLUSION

This study demonstrates the utility of IO vancomycin in primary THA with increased local tissue and decreased systemic concentrations. With positive findings in an area without tourniquet use, IO may be considered for antibiotic delivery for alternative procedures.

Study protocol: The DAICY trial-dual versus single-antibiotic impregnated cement in primary hemiarthroplasty for femoral neck fracture-a register-based cluster-randomized crossover-controlled trial

BACKGROUND AND PURPOSE

Older patients with a displaced femoral neck fracture (FNF) are often treated with a cemented primary hemiarthroplasty (HA). The DAICY trial investigates whether high-dose dual-impregnated antibioticloaded cement (DIAC) including gentamicin and clindamycin can reduce the risk of periprosthetic joint infection (PJI) in comparison with low-dose single-impregnated gentamicin antibiotic-loaded cement (SIAC), in patients ≥ 60 years treated with a cemented HA for a displaced FNF.

STUDY DESIGN

The trial is a national, multicenter, register-based, cluster-randomized, crossover trial. Patients ≥ 60 years with a non-pathological, displaced FNF (Type Garden 3-4/AO 31-B2 or B3) suitable for HA according to local guidelines are eligible for inclusion. Participating orthopedic departments will be randomized to start with either SIAC (control group) or DIAC treatment (intervention group) for 2 years. After 2 years, the study departments will then change to the other treatment arm for the remaining 2 years of the study. Approximately 7,000 patients will be included. The study is pragmatic in that the choice of implant brands, surgical approach and peri- and postoperative protocols follow the local routines of each participating department. All outcome variables will be retrieved after linkage of the study cohort to the following Swedish registers: the Fracture Register, the Arthroplasty Register, the National Patient Register and the Prescribed Drug Registry Outcome: The primary outcome will be periprosthetic joint infection of the index joint within 1 year after surgery. Secondary outcomes will be any reoperation on the index joint, mortality within 90 days and 1 year, resistance patterns of causative bacteria in cases of PJI, and health economics. Potential added value: This trial is designed to support or refute the efficacy of DIAC used in patients with a displaced FNF, potentially reducing PJI and resource allocation. Start of the trial and estimated duration - The DAICY trial started recruiting patients in January 2022 and will continue recruiting for approximately 4 years. Complete follow-up expected in 5 years.

Implementing large-scale data quality validation in a national arthroplasty registry to improve compliance

Data of high quality are critical for the meaningful interpretation of registry information. The National Joint Registry (NJR) was established in 2002 as the result of an unexpectedly high failure rate of a cemented total hip arthroplasty. The NJR began data collection in 2003. In this study we report on the outcomes following the establishment of a formal data quality (DQ) audit process within the NJR, within which each patient episode entry is validated against the hospital unit’s Patient Administration System and vice-versa. This process enables bidirectional validation of every NJR entry and retrospective correction of any errors in the dataset. In 2014/15 baseline average compliance was 92.6% and this increased year-on-year with repeated audit cycles to 96.0% in 2018/19, with 76.4% of units achieving > 95% compliance. Following the closure of the audit cycle, an overall compliance rate of 97.9% was achieved for the 2018/19 period. An automated system was initiated in 2018 to reduce administrative burden and to integrate the DQ process into standard workflows. Our processes and quality improvement results demonstrate that DQ may be implemented successfully at national level, while minimizing the burden on hospitals.

Cite this article: Bone Jt Open 2022;3(9):716–725.

Estimating incidence rates of periprosthetic joint infection after hip and knee arthroplasty for osteoarthritis using linked registry and administrative health data

AIMS

The aim of this study was to estimate the 90-day periprosthetic joint infection (PJI) rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA) for osteoarthritis (OA).

METHODS

This was a data linkage study using the New South Wales (NSW) Admitted Patient Data Collection (APDC) and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), which collect data from all public and private hospitals in NSW, Australia. Patients who underwent a TKA or THA for OA between 1 January 2002 and 31 December 2017 were included. The main outcome measures were 90-day incidence rates of hospital readmission for: revision arthroplasty for PJI as recorded in the AOANJRR; conservative definition of PJI, defined by T84.5, the PJI diagnosis code in the APDC; and extended definition of PJI, defined by the presence of either T84.5, or combinations of diagnosis and procedure code groups derived from recursive binary partitioning in the APDC.

RESULTS

The mean 90-day revision rate for infection was 0.1% (0.1% to 0.2%) for TKA and 0.3% (0.1% to 0.5%) for THA. The mean 90-day PJI rates defined by T84.5 were 1.3% (1.1% to 1.7%) for TKA and 1.1% (0.8% to 1.3%) for THA. The mean 90-day PJI rates using the extended definition were 1.9% (1.5% to 2.2%) and 1.5% (1.3% to 1.7%) following TKA and THA, respectively.

CONCLUSION

When reporting the revision arthroplasty for infection, the AOANJRR substantially underestimates the rate of PJI at 90 days. Using combinations of infection codes and PJI-related surgical procedure codes in linked hospital administrative databases could be an alternative way to monitor PJI rates.Cite this article: Bone Joint J 2022;104-B(9):1060-1066.

The accuracy of reporting of periprosthetic joint infection to the Australian Orthopaedic Association National Joint Replacement Registry

Aims

National joint registries under-report revisions for periprosthetic joint infection (PJI). We aimed to validate PJI reporting to the Australian Orthopaedic Association National Joint Arthroplasty Registry (AOANJRR) and the factors associated with its accuracy. We then applied these data to refine estimates of the total national burden of PJI.

Methods

A total of 561 Australian cases of confirmed PJI were captured by a large, prospective observational study, and matched to data available for the same patients through the AOANJRR.

Results

In all, 501 (89.3%) cases of PJI recruited to the prospective observational study were successfully matched with the AOANJRR database. Of these, 376 (75.0%) were captured by the registry, while 125 (25.0%) did not have a revision or reoperation for PJI recorded. In a multivariate logistic regression analysis, early (within 30 days of implantation) PJIs were less likely to be reported (adjusted odds ratio (OR) 0.56; 95% confidence interval (CI) 0.34 to 0.93; p = 0.020), while two-stage revision procedures were more likely to be reported as a PJI to the registry (OR 5.3 (95% CI 2.37 to 14.0); p ≤ 0.001) than debridement and implant retention or other surgical procedures. Based on this data, the true estimate of the incidence of PJI in Australia is up to 3,900 cases per year.

Conclusion

In Australia, infection was not recorded as the indication for revision or reoperation in one-quarter of those with confirmed PJI. This is better than in other registries, but suggests that registry-captured estimates of the total national burden of PJI are underestimated by at least one-third. Inconsistent PJI reporting is multifactorial but could be improved by developing a nested PJI registry embedded within the national arthroplasty registry.

Cite this article: Bone Jt Open 2022;3(5):367–373.

Surgical Helmet Systems Are Associated With a Lower Rate of Prosthetic Joint Infection After Total Knee Arthroplasty: Combined Results From the New Zealand Joint Registry and Surgical Site Infection Improvement Programme

BACKGROUND

This study aimed to identify the risk factors, in particular the use of surgical helmet systems (SHSs), for prosthetic joint infection (PJI) after total knee arthroplasty (TKA). Data recorded by the New Zealand Surgical Site Infection Improvement Programme (SSIIP) and the New Zealand Joint Registry (NZJR) were combined and analyzed.

METHODS

Primary TKA procedures performed between July 2013 and June 2018 that were recorded by both the SSIIP and NZJR were analyzed. Two primary outcomes were measured: (1) PJI within 90 days as recorded by the SSIIP and (2) revision TKA for deep infection within 6 months as recorded by the NZJR. Univariate and multivariate analyses were performed to identify risk factors for both outcomes with results considered significant at P < .05.

RESULTS

A total of 19,322 primary TKAs were recorded by both databases in which 97 patients had a PJI within 90 days as recorded by the SSIIP (0.50%), and 90 patients had a revision TKA for deep infection within 6 months (0.47%) as recorded by the NZJR. An SHS was associated with a lower rate of PJI (adjusted odds ratio [OR] = 0.50, P = .008) and revision for deep infection (adjusted OR = 0.55, P = .022) than conventional gowning. Male sex (adjusted OR = 2.6, P < .001) and an American Society of Anesthesiologists score >2 were patient risk factors for infection (OR = 2.63, P < .001 for PJI and OR = 1.75, P = .017 for revision for deep infection).

CONCLUSION

Using contemporary data from the SSIIP and NZJR, the use of the SHS was associated with a lower rate of PJI after primary TKA than conventional surgical gowning. Male sex and a higher American Society of Anesthesiologists score continue to be risk factors for infection.

The presence of a draining sinus is associated with failure of re-implantation during two-stage exchange arthroplasty

Background: Reinfection rates after two-stage exchange arthroplasty for prosthetic joint infection (PJI) have been reported as high as 33 % in the literature. Understanding risk factors for treatment failure will help to preoperatively counsel patients on the likelihood of successful treatment and possibly influence the surgeon's treatment algorithm. This study aimed to delineate whether the presence of a draining sinus tract is associated with risk of failure of two-stage exchange arthroplasty. Methods: We performed a single institution, multi-center retrospective chart review of outcomes of patients treated for PJI with two-stage exchange arthroplasty between June 2006 and May 2016. For patients treated prior to 2011, PJI was defined based on the preoperative work-up and intraoperative findings as determined by the attending surgeon. After 2011, PJI was defined using MSIS consensus criteria. All patients had a minimum of follow-up of 2 years or treatment failure prior to 2 years. Treatment failure was defined as reinfection or failure to complete two-stage exchange secondary to persistent infection or other host factors. Operative reports and clinical notes were reviewed to assess for presence of a draining sinus tract. Results: 240 patients were treated for PJI with intended two-stage exchange arthroplasty. The overall rate of treatment failure was 29.6 % (71/240), while the overall rate of reinfection was 13.3 % (32/240). A total of 39 patients did not complete second stage revision; final treatment for these patients was amputation, fusion, or chronic antibiotic suppression. A total of 52 of 240 patients (21.7 %) had a draining sinus tract at presentation. Patients with a sinus tract were significantly less likely to be replanted compared to those without a sinus tract at presentation (13.3 % vs. 26.9 %, p=0.02). However, when accounting for all mechanisms of treatment failure, including reinfection following replantation, there was no statistically significant difference detected between the sinus and no-sinus groups (27.7 % vs. 36.5 %, p=0.22). Discussion: A draining sinus tract represents a chronic, deep infectious process with ultimate compromise of overlying soft tissues. Thus we hypothesized it would be associated with failure in a two-stage exchange arthroplasty. These data demonstrate that patients with a draining sinus are significantly less likely to undergo re-implantation. This provides evidence to the paucity of data surrounding draining sinuses and two-stage PJI treatment.

Is two-stage revision surgery for infected hip arthroplasty worth the suffering, resources and results compared to one-stage?

PURPOSE

Periprosthetic joint infection (PJI) is the most serious complication of total hip arthroplasty. The treatment is usually revision in either 1 or 2 stages. This study analyses revision with impaction bone grafting for periprosthetic joint infection of the hip and compares 1- and 2-stage strategies.

PATIENTS AND METHODS

We reviewed 55 consecutive cases (54 patients) of revision arthroplasty for PJI carried out at our hospital between 2002 and 2016. Of these, 46 were 2-stage procedures. 21 had vancomycin mixed in with the bone graft, and all had gentamycin-containing bone cement. The total perioperative blood loss, duration of operation, and length of hospital stay were recorded. Clinical and radiological results were analysed for 48 hips at 2-16 years follow-up.

RESULTS

No PJI remained at follow-up. 3 patients (6%) had undergone revision for all causes. 1 had radiological signs of mechanical loosening but was not revised. 2-stage procedures had a significantly longer operating time (409 vs. 238 min) and hospital stay (34 vs. 13 days), greater blood loss (2764 vs. 1638 ml), and lower mean functional hip score (15.9 vs. 17.5) at follow-up than the one-stage procedures.

INTERPRETATION

Revision total hip arthroplasty for PJI with vancomycin-loaded impaction bone grafting is a safe method that achieves both the restoration of bone stock and resolution of the infection. This single-stage procedure could therefore be the new gold standard for treatment of non-complicated PJI in the hip.

EPOS trial: the effect of air filtration through a plasma chamber on the incidence of surgical site infection in orthopaedic surgery: a study protocol of a randomised, double-blind, placebo-controlled trial

INTRODUCTION

There is controversy regarding the importance of air-transmitted infections for surgical site infections (SSIs) after orthopaedic surgery. Research has been hindered by both the inability in blinding the exposure, and by the need for recruiting large enough cohorts. The aim of this study is to investigate whether using a new form of air purifier using plasma air purification (PAP) in operating rooms (ORs) lowers the SSI rate or not.

METHODS AND ANALYSIS

Multicentre, double-blind, cluster-randomised, placebo-controlled trial conducted at seven hospitals in 2017-2022. All patients that undergo orthopaedic surgery for minimum 30 min are included. Intervention group: patients operated in OR with PAP devices turned on.

CONTROL GROUP

patients operated in OR with PAP devices turned off. Randomisation: each OR will be randomised in periods of 4 weeks, 6 weeks or 8 weeks to either have the devices on or off.

PRIMARY OUTCOME

any SSI postoperatively defined as a composite endpoint of any of the following: use of isoxazolylpenicillin, clindamycin or rifampicin for 2 days or more, International Classification of Diseases codes or Nordic Medico-Statistical Committee codes indicating postoperative infection. In a second step, we will perform a chart review on those patients with positive indicators of SSI to further validate the outcome. Secondary outcomes are described in the Methods section. Power: we assume an SSI rate of 2%, an SSI reduction rate of 25% and we need approximately 45 000 patients to attain a power of 80% at a significance level of 0.05.

ETHICS AND DISSEMINATION

The study is approved by the Swedish Ethical Review Authority. The interim analysis results from the study will be presented only to the researchers involved unless the study thereafter is interrupted for whatever reason. Publication in a medical journal will be presented after inclusion of the last patient.

TRIAL REGISTRATION NUMBER

NCT02695368.

Similar periprosthetic joint infection rates after and before a national infection control program: a study of 45,438 primary total knee arthroplasties

Background and purpose - Strenuous efforts to minimize postoperative infection rates have been made, including the Swedish nationwide initiative Prosthesis Related Infections Shall be Stopped (PRISS). This study calculated the incidence rate of periprosthetic joint infection (PJI) following primary total knee arthroplasty (TKA) before and after PRISS. Patients and methods - All 45,438 primary TKAs registered in the Swedish Knee Arthroplasty Register (SKAR) during 2007-2008 and 2012-2013 were included. Matched data on antibiotic prescriptions were obtained from the Swedish Prescribed Drug Register (SPDR). All patients with ≥ 28 days of continuous antibiotic treatment within 2 years of primary surgery had their medical charts reviewed to identify cases of PJI. The incidence rate was calculated by dividing the number of PJIs by the total time at risk during each time period and presented as percentages with 95% confidence interval (CI). Results - 644 PJIs were identified, equaling a 2-year incidence rate of 1.45% (CI 1.34-1.57). The incidence rate was 1.44% (CI 1.27-1.61) before PRISS and 1.46% (CI 1.31-1.61) after. Diagnosis was made within 30 days of primary TKA in 52%, and within 90 days in 73% of cases. 603 cases were reoperated on or revised. Median time from operation to diagnosis was 29 days (1-716), for both time periods. Debridement with exchange of the insert was performed in 32% and 63% of cases before and after PRISS, respectively. Interpretation - We found similar incidence rates before and after the PRISS initiative without any statistically significant difference. Time to diagnosis was similar during both time periods. The project may have contributed to increased compliance with treatment protocols.

Increasing but levelling out risk of revision due to infection after total hip arthroplasty: a study on 108,854 primary THAs in the Norwegian Arthroplasty Register from 2005 to 2019

Background and purpose - Focus on prevention, surveillance, and treatment of infection after total hip arthroplasty (THA) in the last decade has resulted in new knowledge and guidelines. Previous publications have suggested an increased incidence of surgical revisions due to infection after THA. We assessed whether there have been changes in the risk of revision due to deep infection after primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 2005-2019.Patients and methods - Primary THAs reported to the NAR from January 1, 2005 to December 31, 2019 were included. Adjusted Cox regression analyses with the first revision due to deep infection after primary THA were performed. We investigated changes in the risk of revision as a function of time of primary THA. Time was stratified into 5-year periods. We studied the whole population of THAs, and the subgroups: all-cemented, all-uncemented, reverse hybrid (cemented cup), and hybrid THAs (cemented stem). In addition, we investigated factors that were associated with the risk of revision, and changes in the time span from primary THA to revision.Results - Of the 108,854 primary THAs that met the inclusion criteria, 1,365 (1.3%) were revised due to deep infection. The risk of revision due to infection, at any time after primary surgery, increased through the period studied. Compared with THAs implanted in 2005-2009, the relative risk of revision due to infection was 1.4 (95% CI 1.2-1.7) for 2010-2014, and 1.6 (1.1-1.9) for 2015-2019. We found an increased risk for all types of implant fixation. Compared to 2005-2009, for all THAs, the risk of revision due to infection 0-30 days postoperatively was 2.2 (1.8-2.8) for 2010-2014 and 2.3 (1.8-2.9) for 2015-2019, 31-90 days postoperatively 1.0 (0.7-1.6) for 2010-2014 and 1.6 (1.0-2.5) for 2015-2019, and finally 91 days-1 year postoperatively 1.1 (0.7-1.8) for 2010-2014 and 1.6 (1.0-2.6) for 2015-2019. From 1 to 5 years postoperatively, the risk of revision due to infection was similar to 2005-2009 for both the subsequent time periodsInterpretation - The risk of revision due to deep infection after THA increased throughout the period 2005-2019, but appears to have levelled out after 2010. The increase was mainly due to an increased risk of early revisions, and may partly have been caused by a change of practice rather than a change in the incidence of infection.

Completeness and capture rate of publicly funded arthroplasty procedures in the New Zealand Joint Registry

BACKGROUND

Registry-based studies have become more common due to the availability of a large study cohort. However, the validity of findings is dependent on the completeness of the registry. This study aimed to validate the capture rate of the New Zealand Joint Registry (NZJR) by matching procedures that have been recorded separately via clinical coding by the New Zealand Government's National Surgical Site Infection Improvement Programme (SSIIP).

METHODS

The National Health Index, a unique identification code for all patients, was combined with the arthroplasty procedure performed (primary total knee arthroplasty (TKA), primary total hip arthroplasty (THA), revision TKA or revision THA) and operation side. Publicly funded procedures recorded in the NZJR were matched with procedures recorded by the SSIIP on a record-by-record basis. This identified the total number of arthroplasty procedures performed in New Zealand, which was used as the denominator value to calculate the procedure capture rate of the NZJR.

RESULTS

Between 2013 and 2018, 24 556 primary TKA, 28 970 primary THA, 2107 revision TKA and 4263 revision THA procedures were recorded by both datasets. The NZJR recorded 95.5% of primary TKA procedures, 96.3% of primary THA procedures, 97.1% of revision TKA procedures and 95.2% of revision THA procedures.

CONCLUSION

The NZJR recorded >95% of publicly funded arthroplasty procedures. In contrast, there were inaccuracies in clinical coding by hospitals, particularly with revision procedures, demonstrating the benefits of an arthroplasty registry. However, data recorded by an infection surveillance programme may supplement arthroplasty registry data to strengthen the quality of research.

Exchange of Modular Components Improves Success of Debridement, Antibiotics, and Implant Retention: An Observational Study of 575 Patients with Infection After Primary Total Hip Arthroplasty

Debridement, antibiotics, and implant retention (DAIR) is a surgical treatment for periprosthetic joint infection (PJI). DAIR is a desirable treatment option from an economic and patient perspective, if successful. The aim of this observational study was to compare the rates of success, defined as no additional reoperations due to PJI, between DAIR with exchange of modular components and DAIR without exchange in patients who had first-time PJI after primary total hip arthroplasty (THA).

METHODS

Patients with PJI at the site of a primary THA who were treated with DAIR in Sweden between January 1, 2009, and December 31, 2016, were identified in the Swedish Hip Arthroplasty Register. Supplementary questionnaires were sent to orthopaedic departments for additional variables of interest related to PJI. The primary end point was another reoperation due to PJI within 2 years after the first-time DAIR. DAIR with exchange was compared with DAIR without exchange using Kaplan-Meier survival analysis and Cox regression analysis.

RESULTS

A total of 575 patients treated with DAIR for a first-time PJI at the site of a primary THA were analyzed; 364 underwent component exchange and 211 did not. The exchange of components was associated with a lower rate of reoperations due to PJI after DAIR (28.0%) compared with non-exchange (44.1%). The Kaplan-Meier implant survival estimate for exchange was 71.4% (95% confidence interval [CI] = 66.9% to 76.3%) compared with 55.5% (95% CI = 49.1% to 62.7%) for non-exchange. With the analysis adjusted for confounders, DAIR with exchange was associated with a significantly decreased risk of another reoperation due to PJI compared with non-exchange (hazard ratio [HR] = 0.51 [95% CI = 0.38 to 0.68]).

CONCLUSIONS

In patients with a first-time PJI at the site of a primary THA, DAIR with exchange of modular components was superior to non-exchange DAIR. Surgeons should strive to exchange components when they perform DAIR, but there is a need to further identify how DAIR best should be practiced and which patients benefit from it.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Outcome of revision hip arthroplasty in patients younger than 55 years: an analysis of 1,037 revisions in the Dutch Arthroplasty Register

Background and purpose - The increasing use of hip arthroplasties in young patients will inevitably lead to more revision procedures at younger ages, especially as the outcome of their primary procedures is inferior compared with older patients. However, data on the outcome of revision hip arthroplasty in young patients are limited. We determined the failure rates of revised hip prostheses performed in patients under 55 years using Dutch Arthroplasty Register (LROI) data.Patients and methods - All 1,037 revised hip arthroplasty procedures in patients under 55 years at the moment of revision registered in the LROI during the years 2007-2018 were included. Kaplan-Meier survival analyses were used to calculate failure rates of revised hip arthroplasties with endpoint re-revision for any reason. Competing risk analyses were used to determine the probability of re-revision for the endpoints infection, dislocation, acetabular and femoral loosening, while other reasons for revisions and death were considered as competing risks.Results - Mean follow-up of revision procedures was 3.9 years (0.1-12). 214 re-revisions were registered. The most common reason for the index revision was dislocation (20%); the most common reason for re-revision was infection (35%). The 5-year failure rate of revised hip prostheses was 22% (95% CI 19-25), and the 10-year failure rate was 28% (CI 24-33). The 10-year cumulative failure rates of index revisions with endpoint re-revision for infection was 7.8% (CI 6.1-9.7), acetabular loosening 7.0% (CI 4.1-11), dislocation 3.8% (CI 2.6-5.2), and femoral loosening 2.7% (CI 1.6-4.1). The 10-year implant failure rate of index revisions for infection was 45% (CI 37-55) with endpoint re-revision for any reason.Interpretation - Failure rate of revised hip prostheses in patients under 55 years is worrisome, especially regarding index revisions due to infection. This information facilitates realistic expectations for these young patients at the time of primary THA.

Lower reoperation rate with locking plates compared with conventional plates in Vancouver type C periprosthetic femoral fractures: A register study of 639 cases in Sweden

AIM

To investigate demographics and outcomes of Vancouver type C periprosthetic femoral fractures (PPFF) treated with open reduction and internal fixation.

METHODS

Patient data were obtained from medical charts of cases reported to the Swedish Hip Arthroplasty Register and/or from the National Patient Register. Vancouver type C fractures undergoing surgery between 2001 and 2011, in patients who had received their primary THR between 1979 and 2011, were included. Any further reoperation performed between 2001 and 2013 and related to the PPFF constituted the primary outcome.

RESULTS

A total of 632 patients with 639 Vancouver type C fractures were identified. The majority of the patients were women (84%) and they had a fracture distal to a cemented stem (95%). The mean age at the time of fracture was 72 years. Treatment was performed with a locking plate (363 cases), a conventional plate (184 cases), an intramedullary nail (62 cases), or with double plating (30 cases). The overall reoperation rate was 17%, and mortality within one year of the operation was 16%. Locking plates had a significantly lower reoperation rate than conventional plates (p<0.001) and intramedullary nailing (p = 0.005). Interprosthetic femoral fractures did not have a statistically different outcome compared with non-IPFFs.

CONCLUSIONS

The lowest reoperation rate was observed using locking plates in Vancouver type C fractures when compared with conventional plates or intramedullary nailing. The presence of an ipsilateral knee prosthesis did not influence the outcome of the surgical treatment.

The risk of revision after total hip arthroplasty in young patients depends on surgical approach, femoral head size and bearing type; an analysis of 19,682 operations in the Dutch arthroplasty register

Background

Total hip arthroplasty (THA) is used increasingly in younger patients. There is little knowledge about the effect of THA characteristics on risk of revision, especially in young patients. Therefore, we studied the influence of both patient-related and surgical factors on the risk of revision using data from the Dutch Arthroplasty Registry (LROI).

Methods

All patients younger than 55 years with a primary THA implanted in the Netherlands between 2007 and 2017 were selected (n = 19,682). The covariates age, sex, primary diagnosis, ASA-classification, surgical approach, fixation method, bearing type, head size and year of surgery were entered into Cox proportional hazards models to calculate hazard ratios for the risk of revision.

Results

The overall 5-year survival of primary THA was 95.3% (95% CI, 94.9–95.6). Use of the anterior approach resulted in a lower risk of revision than the use of the posterolateral approach (HR: 0.66, 95% CI: 0.47–0.92). THAs with a head diameter ≥ 38 mm had a higher risk of revision (HR: 1.90, 95% CI: 1.33–2.72) than THAs with 32 mm heads. Use of MoM bearings resulted in an increased risk when compared to C-PE (HR: 1.76, 95% CI: 1.27–2.43).

Conclusion

The risk of revision in patients younger than 55 years depends on surgical approach, head size and bearing type. The anterior approach resulted in a decreased risk of revision, whereas use of ≥38 mm heads and MoM bearings resulted in an increased risk of revision for any reason.

Reduced Revision Risk for Dual-Mobility Cup in Total Hip Replacement Due to Hip Fracture: A Matched-Pair Analysis of 9,040 Cases from the Nordic Arthroplasty Register Association (NARA)

BACKGROUND

The dual-mobility acetabular cup (DMC) has an additional bearing consisting of a mobile polyethylene component between the prosthetic head and the outer metal shell. This design has gained popularity in revision total hip arthroplasty (THA) and in primary treatment of femoral neck fractures with the anticipation of a reduced risk of THA instability. Our primary aim was to evaluate the overall revision risk of these cups on the basis of data from the Nordic Arthroplasty Register Association (NARA) database, and our secondary aim was to study specific revision causes including dislocation.

METHODS

Propensity score matching for age, sex, fixation of the cup and stem, and the year of surgery (2001 to 2014) was used to match 4,520 hip fractures treated with a DMC to 4,520 hip fractures treated with conventional THA (control group). Competing risk regression analyses with revision or death as the end point were used. Revision was defined as a secondary surgical procedure in which any component of the implant was removed or exchanged. In addition, revision of the cup was analyzed.

RESULTS

The DMCs had a lower risk of revision compared with conventional THA, with an adjusted hazard ratio (AHR) of 0.75 (95% confidence interval [CI] = 0.62 to 0.92). This was consistent after adjusting for surgical approach. DMCs had a lower risk of revision due to dislocation (AHR = 0.45 [95% CI = 0.30 to 0.68]) but we found no difference regarding revision for deep infection. Revision of the acetabular component, both in general and due to dislocation, was more frequent with the use of conventional cups. The risk of death was higher in the DMC group (AHR = 1.49 [95% CI = 1.40 to 1.59]).

CONCLUSIONS

The use of a DMC as primary treatment for hip fracture was associated with a lower risk of revision in general and due to dislocation in particular. The total number of DMCs analyzed (4,520) likely exceeds any cohort of DMC-treated fractures published to date.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

First results of a uniform regional treatment protocol and registration for acute prosthetic join infection in the South-East of the Netherlands

Introduction: Prosthetic joint infection (PJI) is a relatively uncommon (average incidence 0.5-2%) but devastating complication, with significant morbidity and leading to tremendously increased health care costs. In 2013, delegates from nine hospitals covering a large region in the South-East Netherlands composed one combined treatment protocol for acute PJI of total hip and knee arthroplasty (THA and TKA). This protocol was based on the definition of acute PJI according to Workgroup of the American Musculoskeletal Infection Society (MSIS) and the principles of debridement, antibiotics, irrigation and retention (DAIR).

Methods: Patients with a THA or TKA treated with DAIR because of suspicion of PJI were selected from the online PJI database. PJI was defined as at least two phenotypically identical pathogens, isolated in cultures from at least two separate tissues, obtained from the affected prosthetic joint. Acute PJIs, occurring within 90 days after primary implantation, between January 2014 and December 2016, were analyzed. We analyzed the PJI incidence rate, patient clinical and microbiological characteristics of PJI, outcome of the DAIR treatment and adherence to the regional protocol.

Results: A total of 310 primary THA or TKA with a suspected PJI were registered in the regional PJI database, 236 met the definition of acute PJI, representing overall incidence of 1.12%. Following the regional treatment protocol replacement of exchangeable parts took place in 45% in 2014 to 70% in 2016. After 12 months follow-up, prosthesis retention was achieved in 87% and 3% of the patients died within one year after the primary surgery.

Conclusion: Results of the regional cohort are in line with the available literature. Regional collaboration and regular feedback on registered data resulted in better adherence to the combined treatment protocol. Despite our attempts to improve PJI care, PJI remains a serious complication of THA and TKA with a significant mortality rate and burden for the patient.

Incidence and demographics of 1751 surgically treated periprosthetic femoral fractures around a primary hip prosthesis

INTRODUCTION

Periprosthetic femoral fractures (PPFF), treated surgically, have been recorded in the Swedish Hip Arthroplasty Register (SHAR) since 1979. It is postulated that fractures treated with other methods other than stem revision have a lower registration rate, which may lead to incomplete registry data and thus, inaccurate information. We collected all PPFFs surgically treated in Sweden between 2001 and 2011 with the purpose of studying the annual incidence, demographics and distribution of fracture types with regard to type of fixation.

METHODS

Data was linked between the SHAR and the National Patient Register (NPR) in order to detect even those PPFFs not reported to the SHAR. Fractures were classified according to the Vancouver classification system, based on information collected from the medical charts. This procedure was validated with observer variation analysis compared to fracture classification based on radiographs. In total 1751 first-time PPFFs around primary conventional stems were included.

RESULTS

The incidence of PPFF increased from about 1.0 per 1000 primary THRs to 1.4. Vancouver type C fractures (37% of all fractures) were more common than previously reported, and more common in cemented than in uncemented stems. The 3 most common stem designs involved were Exeter polished, Lubinus SPII, and Charnley (66.3% of all stems), partly reflecting their occurrence in the Swedish THR population.

DISCUSSION

The incidence of PPFFs has increased in Sweden during the period 2001 to 2011. The improved reporting of type C fractures, after data-linking, revealed an almost 4 times higher incidence compared to previous register studies in Sweden.

Similar Risk of Re-Revision in Patients after One- or Two-Stage Surgical Revision of Infected Total Hip Arthroplasty: An Analysis of Revisions in the Swedish Hip Arthroplasty Register 1979⁻2015

Late chronic infection is a devastating complication after total hip arthroplasty (THA) and is often treated with surgery. The one-stage surgical procedure is believed to be the more advantageous from a patient and cost perspective, but there is no consensus on whether the one- or two-stage procedure is the better option. We analysed the risk for re-revision in infected primary THAs repaired with either the one- or two-stage method. Data was obtained from the Swedish Hip Arthroplasty Register and the study groups were patients who had undergone a one-stage (n = 404) or two-stage (n = 1250) revision due to infection. Risk of re-revision was analysed using Kaplan–Meier analysis with log-rank test and Cox regression analysis. The cumulative survival rate was similar in the two groups at 15 years after surgery (p = 0.1). Adjusting for covariates, the risk for re-revision due to all causes did not differ between patients who were operated on with the one- or two-stage procedure (Hazard Ratio (HR) = 0.9, 95% Confidence Interval (C.I.) = 0.7–1.2, p = 0.5). The risk for re-revision due to infection (HR = 0.7, 95% C.I. = 0.4–1.1, p = 0.2) and aseptic loosening (HR = 1.2, 95% C.I. = 0.8–1.8, p = 0.5) was similar. This study could not determine whether the one-stage method was inferior in cases when the performing surgeons chose to use the one-stage method.

The design of the cemented stem influences the risk of Vancouver type B fractures, but not of type C: an analysis of 82,837 Lubinus SPII and Exeter Polished stems

Background and purpose - In total hip replacements, stem design may affect the occurrence of periprosthetic femoral fracture. We studied risk factors for fractures around and distal to the 2 most used cemented femoral stems in Sweden. Patients and methods - This is a register study including all standard primary Lubinus SPII and Exeter Polished stems operated in Sweden between 2001 and 2009. The outcome was any kind of reoperation due to fracture around (Vancouver type B) or distal to the stem (Vancouver type C), with use of age, sex, diagnosis at primary THR, and year of index operation as covariates in a Cox regression analysis. A separate analysis of the primary osteoarthritis patient group was done in order to evaluate eventual influence of the surgical approach (lateral versus posterior) on the risk for Vancouver type B fractures. Results - The Exeter stem had a 10-times (95% CI 7-13) higher risk for type B fractures, compared with the Lubinus, while no statistically significant difference was noticed for type C fractures. The elderly, and patients with hip fracture or idiopathic femoral head necrosis, had a higher risk for both fracture types. Inflammatory arthritis was a risk factor only for type C fractures. Type B fractures were more common in men, and type C in women. A lateral approach was associated with decreased risk for Type B fracture. Interpretation - Stem design influenced the risk for type B, but not for type C fracture. The influence of surgical approach on the risk for periprosthetic femoral fracture should be studied further.

Trabecular metal acetabular components in primary total hip arthroplasty

Background and purpose - Trabecular metal (TM) cups have demonstrated favorable results in acetabular revision and their use in primary total hip arthroplasty (THA) is increasing. Some evidence show that TM cups might decrease periprosthetic infection (PPI) incidence. We compared the survivorship of TM cups with that of other uncemented cups in primary THA, and evaluated whether the use of TM cups is associated with a lower risk of PPI. Patients and methods - 10,113 primary THAs with TM cup and 85,596 THAs with other uncemented cups from 2 high-quality national arthroplasty registries were included. The mean follow-up times were 3.0 years for the TM cups and 3.8 years for the other uncemented cups. Results - The overall survivorship up to 8 years for TM cups and other uncemented cups was 94.4% and 96.2%, respectively (p = < 0.001). Adjusting for relevant covariates in a Cox regression model the TM cups had a persistently higher revision risk than other uncemented cups (HR =1.5, 95% CI 1.4-1.7, p = < 0.001). There was a slightly higher, though not statistically significant, revision rate for PPI in the TM group (1.2, 95% CI 1.0-1.6, p = 0.09). Interpretation - Risk of revision for any reason was higher for the TM cup than for other uncemented cups in primary THA. In contrast to our hypothesis, there was no evidence that the revision rate for PPI was lower in the TM cup patients. Regardless of the promising early and mid-term results for TM cups in hip revision arthroplasty, we would like to sound a note of caution on the increasing use of the TM design, especially in uncomplicated primary THAs, where uncemented titanium cups are considered to provide a reliable outcome.

The association between cement type and the subsequent risk of revision surgery in primary total hip replacement

Background and purpose - To further improve the success of joint replacement surgery, attention needs to be paid to variations associated with improved or worsened outcomes. We investigated the association between the type of bone cement used and the risk of revision surgery after primary total hip replacement. Methods - We conducted a prospective study of data from the National Joint Registry for England and Wales between April 1, 2003 and December 31, 2013. 199,205 primary total hip replacements performed for osteoarthritis where bone cement was used were included. A multilevel over-dispersed piecewise Poisson model was used to estimate differences in the rate of revision by bone cement type adjusted for implant type, head size, age, sex, ASA grade, and surgical approach. Results - The rate of revision was higher in DePuy CMW3 medium viscosity with gentamicin (IRR 2.0, 95% CI 1.5-2.7) and DePuy SmartSet high viscosity plain (IRR 2.7, 95% CI 1.1-5.5), and lower in DePuy CMW1 high viscosity plain (IRR 0.44, 95% CI 0.19-0.89) bone cements compared with Heraeus Palacos high viscosity with gentamicin. Revision rates were similar between plain and antibiotic-loaded bone cement. Interpretation - The majority of bone cements performed similarly well, excluding DePuy SmartSet high viscosity and CMW3 high viscosity with gentamicin, which both had higher revision rates. We found no clear differences by viscosity or antibiotic content.

Antibiotic Prophylaxis and DAIR Treatment in Primary Total Hip and Knee Arthroplasty, A National Survey in The Netherlands

BACKGROUND

To prevent postoperative infection the use of systemic antibiotic prophylaxis is common ground. Type of antibiotic used and duration of prophylaxis are subject to debate. In case of suspected early periprosthetic infection a debridement, antibiotics and implant retention (DAIR) procedure is treatment of first choice. This study evaluated the antibiotic prophylaxis and DAIR treatment protocols nationwide as well as reporting of these DAIR procedures to the national joint registry.

METHODS

All institutions that performed total hip or knee arthroplasty were contacted to complete a 16-question online survey. Questions included availability of a protocol, type and duration of antibiotic prophylaxis used and tendency to register infectious complications in the Dutch Arthroplasty Register.

RESULTS

All ninety-nine consulted institutions responded to this survey. All but one institutions have a standardized hospital based protocol for antibiotic prophylaxis in primary total hip or knee arthroplasty. Cefazolin was antibiotic prophylaxis of choice in ninety-four institutions for both primary hip and knee arthroplasty. In ten institutions one preoperative gift of antibiotic prophylaxis was administered. A protocol describing treatment when suspecting early periprosthetic joint infection was present in seventy-one institutions. When performing a DAIR procedure modular parts were exchanged in seventy institutions in case of a hip prosthesis and in eighty-one institutions in case of a knee prosthesis. Sixty-three institutions register DAIR procedures in the Dutch Arthroplasty Register.

INTERPRETATION

In contradiction to the results of a recent study in Great Britain, we have found only little variety in availability of protocols and in the type of antibiotic used as prophylaxis in primary total hip and knee arthroplasty in The Netherlands. Not every institution has a protocol for treatment in suspicion of early infection. Although mobile parts are exchanged in the majority of cases, there appears to be an underreporting of DAIR procedures in the Dutch Arthroplasty Register.

Reduced revision rate and maintained function after hip arthroplasty for femoral neck fractures after transition from posterolateral to direct lateral approach

Background and purpose - The direct lateral (DL) approach to the hip for femoral neck fractures (FNF) has been shown to reduce the rate of dislocation and reoperations. We evaluate the effect of transition from the posterolateral (PL) to DL approach on reoperation and dislocation rates and patients' reported outcome. Patients and methods - In a prospective cohort study between 2012 and 2015, we enrolled 362 patients (median age 83 years, 70% women, mean follow-up 25 months) with a displaced FNF. The first group of 146 patients were operated using the PL and the second group of 216 patients with a DL approach, after change of our routines. A multivariable Cox regression analysis was used to evaluate factors associated with dislocation and reoperation. A generalized linear model was used to evaluate the functional outcome by comparing WOMAC and Harris hip scores between the 2 groups. Results - The reoperation rate was reduced from 13% in the PL to 6% in the DL group and the dislocation rate from 13% to 4%. Cox proportional hazard analysis identified the PL approach as the only factor associated with an increased risk of reoperation (hazard ratio =2.5, 95% CI 1.2-5.2). Age, sex, ASA classification, type of arthroplasty, cognitive dysfunction, or the experience of the surgeon had no effect on the risk of reoperation. Patient-reported outcome was similar between the 2 groups. Interpretation - In patients with FNF we have reduced the reoperation and dislocation rates by changing the surgical approach used for hip arthroplasty without affecting the patient-reported functional outcome.

Increased Mortality After Prosthetic Joint Infection in Primary THA

BACKGROUND

Revision for prosthetic joint infection (PJI) has a major effect on patients' health but it remains unclear if early PJI after primary THA is associated with a high mortality.

QUESTIONS/PURPOSES

(1) Do patients with a revision for PJI within 1 year of primary THA have increased mortality compared with patients who do not undergo revision for any reason within 1 year of primary THA? (2) Do patients who undergo a revision for PJI within 1 year of primary THA have an increased mortality risk compared with patients who undergo an aseptic revision? (3) Are there particular bacteria among patients with PJI that are associated with an increased risk of death?

METHODS

This population-based cohort study was based on the longitudinally maintained Danish Hip Arthroplasty Register on primary THA performed in Denmark from 2005 to 2014. Data from the Danish Hip Arthroplasty Register were linked to microbiology databases, the National Register of Patients, and the Civil Registration System to obtain data on microbiology, comorbidity, and vital status on all patients. Because reporting to the register is compulsory for all public and private hospitals in Denmark, the completeness of registration is 98% for primary THA and 92% for revisions (2016 annual report). The mortality risk for the patients who underwent revision for PJI within 1 year from implantation of primary THA was compared with (1) the mortality risk for patients who did not undergo revision for any reason within 1 year of primary THA; and (2) the mortality risk for patients who underwent an aseptic revision. A total of 68,504 primary THAs in 59,954 patients were identified, of those 445 primary THAs underwent revision for PJI, 1350 primary THAs underwent revision for other causes and the remaining 66,709 primary THAs did not undergo revision. Patients were followed from implantation of primary THA until death or 1 year of followup, or, in case of a revision, 1 year from the date of revision.

RESULTS

Within 1 year of primary THA, 8% (95% CI, 6%-11%) of patients who underwent revision for PJI died. The adjusted relative mortality risk for patients with revision for PJI was 2.18 (95% CI, 1.54-3.08) compared with the patients who did not undergo revision for any cause (p < 0.001). The adjusted relative mortality risk for patients with revisions for PJI compared with patients with aseptic revision was 1.87 (95% CI, 1.11-3.15; p = 0.019). Patients with enterococci-infected THA had a 3.10 (95% CI, 1.66-5.81) higher mortality risk than patients infected with other bacteria (p < 0.001).

CONCLUSIONS

Revision for PJI within 1 year after primary THA induces an increased mortality risk during the first year after the revision surgery. This study should incentivize further studies on prevention of PJI and on risk to patients with the perspective to reduce mortality in patients who have had THA in general and for patients with PJI specifically.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Periprosthetic Joint Infection Is the Main Cause of Failure for Modern Knee Arthroplasty: An Analysis of 11,134 Knees

BACKGROUND

Although large series from national joint registries may accurately reflect indications for revision TKAs, they may lack the granularity to detect the true incidence and relative importance of such indications, especially periprosthetic joint infections (PJI).

QUESTIONS/PURPOSES

Using a combination of individual chart review supplemented with New Zealand Joint Registry data, we asked: (1) What is the cumulative incidence of revision TKA? (2) What are the common indications for revising a contemporary primary TKA? (3) Do revision TKA indications differ at various followup times after primary TKA?

METHODS

We identified 11,134 primary TKAs performed between 2000 and 2015 in three tertiary referral hospitals. The New Zealand Joint Registry and individual patient chart review were used to identify 357 patients undergoing subsequent revision surgery or any reoperation for PJI. All clinical records, radiographs, and laboratory results were reviewed to identify the primary revision reason. The cumulative incidence of each revision reason was calculated using a competing risk estimator.

RESULTS

The cumulative incidence for revision TKA at 15 years followup was 6.1% (95% CI, 5.1%-7.1%). The two most-common revision reasons at 15 years followup were PJI followed by aseptic loosening. The risk of revision or reoperation for PJI was 2.0% (95% CI, 1.7%-2.3%) and aseptic loosening was 1.2% (95% CI, 0.7%-1.6%). Approximately half of the revision TKAs secondary to PJI occurred within 2 years of the index TKA (95% CI, 0.8%-1.2%), whereas half of the revision TKAs secondary to aseptic loosening occurred 8 years after the index TKA (95% CI, 0.4%-0.7%).

CONCLUSIONS

In this large cohort of patients with comprehensive followup of revision procedures, PJI was the dominant reason for failure during the first 15 years after primary TKA. Aseptic loosening became more important with longer followup. Efforts to improve outcome after primary TKA should focus on these areas, particularly prevention of PJI.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Description of the rates, trends and surgical burden associated with revision for prosthetic joint infection following primary and revision knee replacements in England and Wales: an analysis of the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

OBJECTIVES

To describe the prevalence rates of revision surgery for the treatment of prosthetic joint infection (PJI) for patients undergoing knee replacement, their time trends, the cumulative incidence function of revision for PJI and estimate the burden of PJI at health service level.

DESIGN

We analysed revision knee replacements performed due to a diagnosis of PJI and the linked index procedures recorded in the National Joint Registry from 2003 to 2014 for England and Wales. The cohort analysed consisted of 679 010 index primary knee replacements, 33 920 index revision knee replacements and 8247 revision total knee replacements performed due to a diagnosis of PJI. The prevalence rates, their time trends investigated by time from index surgery to revision for PJI, cumulative incidence functions and the burden of PJI (total procedures) were calculated. Overall linear trends were investigated with log-linear regression.

RESULTS

The incidence of revision total knee replacement due to PJI at 2 years was 3.2/1000 following primary and 14.4/1000 following revision knee replacement, respectively. The prevalence of revision due to PJI in the 3 months following primary knee replacement has risen by 2.5-fold (95% CI 1.2 to 5.3) from 2005 to 2013 and 7.5-fold (95% CI 1.0 to 56.1) following revision knee replacement. Over 1000 procedures per year are performed as a consequence of knee PJI, an increase of 2.8 from 2005 to 2013. Overall, 75% of revisions were two-stage with an increase in use of single-stage from 7.9% in 2005 to 18.8% in 2014.

CONCLUSIONS

Although the risk of revision due to PJI following knee replacement is low, it is rising, and coupled with the established and further predicted increased incidence of both primary and revision knee replacements, this represents an increasing and substantial treatment burden for orthopaedic service delivery in England and Wales. This has implications for future service design and the funding of individual and specialist centres.

Revision for prosthetic joint infection following hip arthroplasty: Evidence from the National Joint Registry

Objectives

We used the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR) to investigate the risk of revision due to prosthetic joint infection (PJI) for patients undergoing primary and revision hip arthroplasty, the changes in risk over time, and the overall burden created by PJI.

Methods

We analysed revision total hip arthroplasties (THAs) performed due to a diagnosis of PJI and the linked index procedures recorded in the NJR between 2003 and 2014. The cohort analysed consisted of 623 253 index primary hip arthroplasties, 63 222 index revision hip arthroplasties and 7585 revision THAs performed due to a diagnosis of PJI. The prevalence, cumulative incidence functions and the burden of PJI (total procedures) were calculated. Overall linear trends were investigated with log-linear regression.

Results

We demonstrated a prevalence of revision THA due to prosthetic joint infection of 0.4/100 procedures following primary and 1.6/100 procedures following revision hip arthroplasty. The prevalence of revision due to PJI in the three months following primary hip arthroplasty has risen 2.3-fold (95% confidence interval (CI) 1.3 to 4.1) between 2005 and 2013, and 3.0-fold (95% CI 1.1 to 8.5) following revision hip arthroplasty. Over 1000 procedures are performed annually as a consequence of hip PJI, an increase of 2.6-fold between 2005 and 2013.

Conclusions

Although the risk of revision due to PJI following hip arthroplasty is low, it is rising and, coupled with the established and further predicted increased incidence of both primary and revision hip arthroplasty, this represents a growing and substantial treatment burden.

Cite this article: E. Lenguerrand, M. R. Whitehouse, A. D. Beswick, S. A. Jones, M. L. Porter, A. W. Blom. Revision for prosthetic joint infection following hip arthroplasty: Evidence from the National Joint Registry. Bone Joint Res 2017;6:391–398. DOI: 10.1302/2046-3758.66.BJR-2017-0003.R1.

One-year incidence of prosthetic joint infection in total hip arthroplasty: a cohort study with linkage of the Danish Hip Arthroplasty Register and Danish Microbiology Databases

OBJECTIVE

To examine the trend of Prosthetic Joint Infections (PJI) following primary total hip arthroplasty (THA) and the antimicrobial resistance of the bacteria causing these infections.

MATERIALS AND METHODS

We identified a population-based cohort of patients in the Danish Hip Arthroplasty Register (DHR) who had primary THA and received their surgery in Jutland or Funen between 2005 and 2014. We followed the patients until revision, emigration, death, or up to 1-year of follow-up. Data from the DHR were combined with those from microbiology databases, the National Register of Patients, and the Civil Registration System. We estimated the cumulative 1-year incidence of PJI for two 5-year periods; 2005-2009 and 2010-2014. The hazard ratio of PJI as a measure of relative risk after adjusting for multiple risk factors was calculated.

RESULTS

Of 48,867 primary THAs identified, 1120 underwent revision within 1 year. Of these, 271 were due to PJI. The incidence of PJI was 0.53% (95% confidence interval (CI): 0.44; 0.63) during 2005-2009 and 0.57% (95% CI: 0.49; 0.67) during 2010-2014. The adjusted relative risk was 1.05 (95% CI: 0.82; 1.34) for the 2010-2014 period vs the 2005-2009 period. The most common micro-organisms identified in the 271 PJI were Staphylococcus aureus (36%) and coagulase-negative staphylococci (CoNS) (33%); others commonly identified included Enterobacteriaceae, enterococci, and streptococci. Antimicrobial resistance to beta-lactams and gentamicin did not change during the study period.

CONCLUSION

The risk of PJI within 1-year after primary THA and the antimicrobial resistance of the most prevalent bacteria remained unchanged during the 2005-2014 study period.

Bacterial Infection and Implant Loosening in Hip and Knee Arthroplasty: Evaluation of 209 Cases

The aim of this study was to evaluate bacteria species detected in a large number of patients treated for prosthetic joint infection of the hip and knee at a single specialized center. Furthermore, the rate of implant loosening was investigated in a time-dependent manner for the most frequently detected bacteria species. A retrospective analysis of patients (n = 209) treated for prosthetic joint infection of the hip and knee was performed. The following parameters were evaluated: C-Reactive Protein (CRP) concentration, microbiological evaluation of tissue samples, loosening of the implant, the time that had elapsed since the primary prosthetic joint replacement, and the duration since the last surgical intervention. Coagulase-negative Staphylococcus spp. were most frequently detected, followed by Staphylococcus aureus. Differences in CRP concentration were detected among various bacteria species. Osteolysis was not associated with one causative agent in particular. Patients who had undergone previous revision surgery had a higher probability of implant loosening. Coagulase-negative Staphylococcus spp. are the most common causative agents of prosthetic joint infection and show no significant differences with regard to implant loosening or the time-course when compared to S. aureus. Infections with Enterococcus spp. seem to develop faster than with other bacteria species. The risk of implant loosening increases with revision surgery, in particular in the hip joint.

The Role of Highly Selective Implant Retention in the Infected Hip Arthroplasty

BACKGROUND

There is debate around how to treat patients with periprosthetic joint infection of the hip. When there is an ingrown component on one side of the arthroplasty and a loose component on the other, treatment is typically revision of the entire construct. There is an argument to retain an ingrown implant in instances in which removal would result in severe bone damage. However, little has been reported on the likelihood of success with this approach.

QUESTIONS/PURPOSES

Among carefully selected patients presenting with an infected total hip arthroplasty (THA) who were treated with joint débridement and at least partial implant retention: (1) What proportion remained apparently free of infection at a minimum of 5 years of followup? (2) What were the Harris hip scores of patients thus treated?

METHODS

Between January 2000 and December 2010, a total of 293 patients were treated surgically at one hospital for a periprosthetic joint infection of the hip. Of these, 18 (2.9%) were treated with an approach that retained either the femoral component or the acetabular component (the removed component was exchanged at this same single-stage procedure). During that time, the general indications for this approach were patients who had complex THAs with ingrown femoral stems or complex acetabular components that were well fixed with no evidence of loosening on radiographs and CT. Patients had to be free from chronic debilitating diseases, had not developed a tracking sinus, and had a positive microbial growth from the hip aspirate. In 12 of these patients, the ingrown cementless femoral component was kept in situ and the femoral head and acetabular component were exchanged. In six patients, complex acetabular reconstructions including augments and/or cages were left in situ, and femoral revision with liner exchange was performed. The technique included removal of the loose component, thorough débridement, synovectomy, and extensive lavage. The ingrown component, be it femoral or acetabular, was thoroughly cleaned, lavaged, and scrubbed. Once there was a clear field, redraping was carried out and new instruments were used to reimplant the other side. In all patients, intravenous antibiotics were used postoperatively for a minimum of 5 days and oral antibiotics for a minimum of 6 weeks based on serology, wound healing, and nutritional markers. None of the patients were lost to followup. Minimum followup was 5 years; median followup was 7.1 years (range, 5-9.9 years).

RESULTS

Reinfection occurred in three patients at 3, 9, and 10 months; all were treated by two-stage revision. No reinfection was noted in the other cases. At latest followup, the mean Harris hip score was 78 (range, 46-89).

CONCLUSIONS

In some patients, staged revision of large and well-fixed components will result in bone damage and compromised function. These results suggest that partial implant retention and joint débridement may be an alternative for those patients who have complex well-fixed acetabular or femoral components, are not immunocompromised, have not developed sinus formation, and we were able to obtain a positive hip aspirate. We caution this technique should not be applied when patients have chronic illness such as diabetes or rheumatoid disease, have a negative hip aspirate for microorganisms, or show any signs of loosening on radiography, CT, or on intraoperative assessment. These results at a minimum of 5 years are reassuring in this small single-center series, but we suggest that the technique not be widely adopted until or unless larger groups of patients with longer term data have been studied.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

New Zealand Joint Registry data underestimates the rate of prosthetic joint infection

Background and purpose - Recent studies have revealed deficiencies in the accuracy of data from joint registries when reoperations for prosthetic joint infections (PJIs) are reported, particularly when no components are changed. We compared the accuracy of data from the New Zealand Joint Registry (NZJR) to a multicenter audit of hospital records to establish the rate of capture for PJI reoperations. Methods - 4,009 cases undergoing total knee or hip arthroplasty performed at 3 tertiary referral hospitals over a 3-year period were audited using multiple hospital datasets and the NZJR. The number of reoperations for PJI that were performed within 2 years of the primary arthroplasty was obtained using both methods and the data were compared. Results - The NZJR reported a 2-year reoperation rate for PJI of 0.67%, as compared to 1.1% from the audit of hospital records, giving the NZJR a sensitivity of 63%. Only 4 of 11 debridement-in-situ-only procedures and 7 of 12 modular exchange procedures were captured in the NZJR. Interpretation - The national joint registry underestimated the rate of reoperation for PJI by one third. Strategies for improving the accuracy of data might include revising and clarifying the registry forms to include all reoperations for PJI and frequent validation of the registry data against other databases.

Validation of the diagnosis 'prosthetic joint infection' in the Danish Hip Arthroplasty Register

AIMS

The purpose of this study was to validate the diagnosis of periprosthetic joint infection (PJI) in the Danish Hip Arthroplasty Register (DHR).

PATIENTS AND METHODS

We identified a cohort of patients from the DHR who had undergone primary total hip arthroplasty (THA) since 1 January 2005 and followed them until first-time revision, death, emigration or until 31 December 2012. Revision for PJI, as registered in the DHR, was validated against a benchmark which included information from microbiology databases, prescription registers, clinical biochemistry registers and clinical records. We estimated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PJI in the DHR alone and in the DHR when combined with microbiology databases.

RESULTS

In total, 1382 of the 37 826 primary THAs in the DHR were registered as having been revised for any cause once 26 patients with errors in registration had been excluded: 232 of these were for PJI. For this group, the sensitivity was 67%, specificity 95%, PPV 77%, and NPV 92%. Combining the data from the DHR with those from microbiology databases increased the sensitivity to 90% and also improved specificity (100%), PPV (98%) and NPV (98%).

CONCLUSION

Only two thirds of revisions for PJI were captured in the DHR and only 77% of the PJI reported to the DHR could be confirmed to be infected.

TAKE HOME MESSAGE

combining the data from the DHR with those from microbiology databases substantially improved the validity of the diagnosis of PJI and should enable future register-based studies.

Increased risk of revision for infection in rheumatoid arthritis patients with total hip replacements

BACKGROUND AND PURPOSE

Medical treatment of rheumatoid arthritis (RA) has changed dramatically over the last 15 years, including immune modulation. We investigated the risk of revision for infection after primary total hip replacement (THR) in patients with rheumatoid arthritis over a 16-year period, and compared it with that in THR patients with osteoarthritis (OA).

PATIENTS AND METHODS

We identified 13,384 THRs in RA patients and 377,287 THRs in OA patients from 1995 through 2010 in a dataset from the Nordic Arthroplasty Register Association (NARA). Kaplan-Meier survival curves, with revision for infection as the endpoint, were constructed. Cox regression analyses were performed to calculate the relative risk (RR) of revision for infection adjusted for age, sex, fixation technique, and year of primary surgery.

RESULTS

RA patients had a 1.3 times (95% CI 1.0-1.6) higher risk of revision for infection. After 2001, this risk increased more for RA patients than for OA patients. During the first 3 months and from 8 years postoperatively, the risk of revision for infection was higher in RA patients with THRs fixated with antibiotic-loaded cement than in corresponding OA patients.

INTERPRETATION

We found a slightly higher overall risk of revision for infection in RA patients than in OA patients, but this difference was only present after 2001. In THRs with antibiotic-loaded cement, the risk of very early and late infections leading to revision was higher in RA patients than in OA patients.