Increased short- and long-term mortality amongst patients with early periprosthetic knee joint infection.

BACKGROUND: Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a severe complication in terms of disability, morbidity, and cost. We performed a study to investigate whether early PJI (within 90 days of primary TKA) is associated with increased mortality. Secondary aims were to compare mortality rates over time and between surgical treatment methods. METHODS: Patients with suspected PJI were identified by linkage of the Swedish Knee Arthroplasty Register (SKAR) and the Swedish Prescribed Drug Register (SPDR) in 2007-2008 and 2012-2013. Medical records of patients receiving more than 4 weeks of continuous antibiotic therapy were subsequently reviewed to verify the PJI diagnosis. Information on mortality was obtained through the SKAR which is updated daily from the tax agency and patients with PJI were compared to patients without PJI. RESULTS: Four hundred sixty-six patients were diagnosed with PJI within 90 days and compared to 40,362 patients without PJI. Mortality rates were significantly higher for PJI patients in both short- and long term: 2.6% vs. 0.8% at 1 year, 4.9% vs. 1.9% at 2 years, 15.7% vs. 7.1% at 5 years, and 38% vs. 21.4% at 10 years. The difference in mortality rate remained after adjusting for sex, age, diagnosis, and time period for surgery with Hazard Ratio 1.8 (95% CI:1.6-2.1). Mortality rates did not differ between time periods, and we found no correlation to surgical treatment. CONCLUSION: Patients with early PJI after primary TKA have an increased mortality rate compared to TKA patients without PJI. Improvements in surgical treatment strategy has not resulted in better survival. Long term difference in mortality rates indicates that PJI is not the sole reason for mortality suggesting a general frailty in PJI patients.

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.

Anti-rheumatic treatment and prosthetic joint infection: an observational study in 494 elective hip and knee arthroplasties.

BACKGROUND: Surgical site infections are more frequent among patients with rheumatic disease. To what extent this is related to immunosuppressive antirheumatic drugs is unclear, as is the value of discontinuing medication perioperatively. The aim of study was to assess the rate of surgical site infections after knee and hip replacement in patients with inflammatory joint disease, with an emphasis on periprosthetic joint infection, and to investigate the influence of treatment with disease-modifying antirheumatic drugs (DMARDs) in this regard. METHODS: Data were collected from 494 primary elective hip (51.4%) and knee arthroplasties, along with demographic and medication data. The primary outcome was surgical site infection during the first year after surgery. RESULTS: In 78% (n = 385) of the cases the patient used 1 to 3 disease-modifying antirheumatic drugs perioperatively. Thirty-two percent (n = 157) of patients used a TNF-alpha inhibitor. The rate of surgical site infection was 3.8% (n = 19). The rate of periprosthetic joint infection was 1.4% (n = 7), all of which occurred after knee arthroplasty. Periprosthetic joint infection occurred in only 1 patient medicating perioperatively with a TNF-alpha inhibitor. CONCLUSION: Surgical site infections were not associated with ongoing medication with disease-modifying antirheumatic drugs. Due to the low event rate this should be interpreted with caution, but our center will maintain its routine of continuing treatment with TNF-alpha inhibitors perioperatively.

Why are antiepileptic drugs continued after successful epilepsy surgery in adults?

OBJECTIVE: Studies have demonstrated that a substantial number of patients continue treatment with antiepileptic drugs (AEDs) for many years after epilepsy surgery despite seizure freedom. In this study, we aimed to investigate why AED treatment is maintained in patients three and seven years after successful epilepsy surgery. To our knowledge, an analysis of this specific subgroup of completely seizure-free patients has not been done before. MATERIAL AND METHODS: Danish patients with medically refractory epilepsy and histopathologically proven hippocampal sclerosis operated between 1995 and 2014 who were reported seizure-free at one-year postsurgery were contacted by telephone in 2017 and retrospectively asked about the reasons to continue or taper AED at three and seven years after the operation. RESULTS: Fifty patients were completely seizure-free three years after the operation. Of those, 31 (62%) were still taking AEDs at three years, thereof 10 (20%) in the same dose and number and half of those on their own wish. At seven years, nine patients were still taking AEDs, two in unchanged number and dose, both on their own wish. Fear of relapse was the most common reason not to withdraw medication. Presurgery seizure frequency for patients taking AEDs at three and seven years was not higher than for those who had discontinued taking AEDs. CONCLUSIONS: A large portion of completely seizure-free patients still take AEDs even seven years after epilepsy surgery. This seems to be largely due to the patients' own wishes and fear of relapse, and unrelated to presurgery seizure frequency. Our results could aid in counseling patients on the decision to withdraw AEDs after successful epilepsy surgery.

Higher risk of revision for infection using systemic clindamycin prophylaxis than with cloxacillin.

Background and purpose - Clindamycin has not been compared with other antibiotics for prophylaxis in arthroplasty. Since 2009, the Swedish Knee Arthroplasty Register (SKAR) has been collecting information on the prophylactic antibiotic regime used at every individual operation. In Sweden, when there is allergy to penicillin, clindamycin has been the recommended alternative. We examined whether there were differences in the rate of revision due to infection depending on which antibiotic was used as systemic prophylaxis. Patients and methods - Patients who had a total knee arthroplasty (TKA) performed due to osteoarthritis (OA) during the years 2009-2015 were included in the study. Information on which antibiotic was used was available for 80,018 operations (55,530 patients). Survival statistics were used to calculate the rate of revision due to infection until the end of 2015, comparing the group of patients who received cloxacillin with those who received clindamycin as systemic prophylaxis. Results - Cloxacillin was used in 90% of the cases, clindamycin in 7%, and cephalosporins in 2%. The risk of being revised due to infection was higher when clindamycin was used than when cloxacillin was used (RR =1.5, 95% CI: 1.2-2.0; p = 0.001). There was no significant difference in the revision rate for other causes (p = 0.2). Interpretation - We advise that patients reporting allergic reaction to penicillin should have their allergic history explored. In the absence of a clear history of type-I allergic reaction (e.g. urticaria, anaphylaxis, or bronchospasm), we suggest the use of a third-generation cephalosporin instead of clindamycin as perioperative prophylaxis when undergoing a TKR. No recommendation can be given regarding patients with type-1 allergy.

75% success rate after open debridement, exchange of tibial insert, and antibiotics in knee prosthetic joint infections.

BACKGROUND AND PURPOSE: Prosthetic joint infection (PJI) is a leading cause of early revision after total knee arthroplasty (TKA). Open debridement with exchange of tibial insert allows treatment of infection with retention of fixed components. We investigated the success rate of this procedure in the treatment of knee PJIs in a nationwide material, and determined whether the results were affected by microbiology, antibiotic treatment, or timing of debridement. PATIENTS AND METHODS: 145 primary TKAs revised for the first time, due to infection, with debridement and exchange of the tibial insert were identified in the Swedish Knee Arthroplasty Register (SKAR). Staphylococcus aureus was the most common pathogen (37%) followed by coagulase-negative staphylococci (CNS) (23%). Failure was defined as death before the end of antibiotic treatment, revision of major components due to infection, life-long antibiotic treatment, or chronic infection. RESULTS: The overall healing rate was 75%. The type of infecting pathogen did not statistically significantly affect outcome. Staphylococcal infections treated without a combination of antibiotics including rifampin had a higher failure rate than those treated with rifampin (RR = 4, 95% CI: 2-10). In the 16 cases with more than 3 weeks of symptoms before treatment, the healing rate was 62%, as compared to 77% in the other cases (p = 0.2). The few patients with a revision model of prosthesis at primary operation had a high failure rate (5 of 8). INTERPRETATION: Good results can be achieved by open debridement with exchange of tibial insert. It is important to use an antibiotic combination including rifampin in staphylococcal infections.

Bacterial colonization and resistance patterns in 133 patients undergoing a primary hip- or knee replacement in Southern Sweden.

BACKGROUND AND PURPOSE: Prosthetic joint infections can be caused by bacteria derived from the patient's skin. The aim of the study was: (1) to determine which bacteria colonize the nose and groin in patients planned for primary hip or knee arthroplasty, (2) to determine the antimicrobial resistance patterns, and (3) to monitor changes in bacterial colonization and resistance patterns connected to surgery. PATIENTS AND METHODS: 2 weeks before scheduled primary hip or knee arthroplasty, culture samples were taken from the anterior nares and from the groin of 133 consecutive patients. At surgery, cloxacillin was given prophylactically and cement with gentamicin was used. 2 weeks after surgery, another set of samples were taken from 120 of these patients. Bacterial findings and resistance patterns were analyzed. RESULTS: Preoperatively, 95% of the patients had coagulase-negative staphylococci (CNS) in the groin and 77% in the nose. The proportion of patients with a methicillin-resistant CNS in the groin increased from 20% preoperatively to 50% postoperatively (p < 0.001), and the proportion of patients with a gentamicin-resistant CNS in the groin increased from 5% to 45% (p < 0.001). 28% of the patients had Staphylococcus aureus in the nose preoperatively, and 7% in the groin. Methicillin-resistant Staphylococcus aureus (MRSA) was found in the nose of 1 patient. INTERPRETATION: In southern Sweden, beta-lactams were effective against 99% of the Staphylococcus aureus strains and 80% of the CNS strains colonizing the patients undergoing primary hip or knee arthroplasty. Gentamicin protects against most CNS strains in cemented primary joint replacements.

Timing of preoperative antibiotics for knee arthroplasties: Improving the routines in Sweden.

BACKGROUND: A slight increase in revisions for infected joint arthroplasties has been observed in the Nordic countries since 2000 for which the reasons are unclear. However, in 2007 a Swedish study of the timing for prophylactic antibiotics in a random sample of knee arthroplasties found that only 57% of the patients had received the antibiotic during the optimal time interval 45-15 minutes before surgery. The purpose of the report was to evaluate the effect of measures taken to improve the timing of prophylactic antibiotics. FINDINGS: Reporting this finding to surgeons at national meetings during 2008 the Swedish Knee Arthroplasty Register (SKAR) introduced a new report form from January 2009 including the time for administration of preoperative antibiotics. Furthermore, the WHO's surgical checklist was introduced during 2009 and a national project was started to reduce infections in arthroplasty surgery (PRISS). The effect of these measures was found to be positive showing that in 2009, 69% of the 12,707 primary knee arthroplasties were reported to have received the prophylaxis within the 45-15 min time interval and 79% of the first 7,000 knee arthroplasties in 2010. A survey concerning the use of the WHO checklist at Swedish hospitals showed that 73 of 75 clinics had introduced a surgical checklist. CONCLUSIONS: By registration and bringing back information to surgeons on the state of infection prophylaxis in combination with the introduction of the WHO checklist and the preventive work done by the PRISS project, the timing of preoperative prophylactic antibiotics in knee arthroplasty surgery was clearly improved.

Inadequate timing of prophylactic antibiotics in orthopedic surgery. We can do better.

BACKGROUND AND PURPOSE: There are rising concerns about the frequency of infection after arthroplasty surgery. Prophylactic antibiotics are an important part of the preventive measures. As their effect is related to the timing of administration, it is important to follow how the routines with preoperative prophylactic antibiotics are working. METHODS: In 114 consecutive cases treated at our own university clinic in Lund during 2008, the time of administration of preoperative prophylactic antibiotic in relation to the start of surgery was recorded from a computerized operation report. In 291 other cases of primary total knee arthroplasty (TKA), randomly selected from the Swedish Knee Arthroplasty Register (SKAR), the type and dose of prophylactic antibiotic as well as the time of administration in relation to the inflation of a tourniquet and to the start of surgery was recorded from anesthetic records. RESULTS: 45% (95% CI: 36-54) of the patients operated in Lund and 57% (CI: 50-64) of the TKAs randomly selected from the SKAR received the preoperative antibiotic 15-45 min before the start of surgery. 53% (CI: 46-61) received antibiotics 15-45 min before inflation of a tourniquet. INTERPRETATION: The inadequate timing of prophylactic antibiotics indicates that the standards of strict antiseptic and aseptic routines in arthroplasty surgery are falling. The use of a simple checklist to ensure the surgical safety may be one way of reducing infections in arthroplasty surgery.

Higher early mortality with simultaneous rather than staged bilateral TKAs: results from the Swedish Knee Arthroplasty Register.

UNLABELLED: Patients with knee osteoarthritis (OA) often present with symptoms that warrant bilateral TKAs. There are potential benefits to operating on both knees on the same day, but the safety of simultaneous bilateral TKAs has been questioned. To evaluate whether there were any differences in 30-day mortality between patients having simultaneous bilateral TKAs and those having staged bilateral TKAs, we analyzed data from the Swedish Knee Arthroplasty Register and the Swedish Cause of Death Register. We included 48,931 patients with OA having 60,062 primary TKAs during 1985 to 2004; 1139 had surgery on both knees on the same day (simultaneous bilateral) and 3432 had surgery on both knees on two different occasions with less than 1 year between operations (staged bilateral). The 30-day mortality after simultaneous bilateral TKAs was 7.53 (confidence interval, 2.62-21.69) times higher than after the second of staged TKA and 3.77 (confidence interval, 2.04-6.98) times higher than after a primary unilateral TKA. Assuming the total risk for a staged procedure is twice that of a unilateral procedure, the risk of mortality within 30 days is 1.94 (confidence interval, 1.05-3.59) times higher with simultaneous than staged TKA. It is safer to operate on one knee at a time. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Five-year follow-up of socket movements and loosening after revision with impacted morselized allograft bone and cement: a radiostereometric and radiographic analysis.

In 1999, we reported on the 2-year results of a series of 21 first-time socket revisions using impacted morselized allograft bone. Seven still migrated between 1.5 and 2 years. Seventeen remained for the current 5-year follow-up. No socket had been rerevised. Five sockets showed signs of radiographic loosening. These 5 cases also exhibited radiographic signs of allograft resorption as well as high rates of socket migration and rotation as measured by radiostereometric analysis. Of the 6 remaining sockets that had migrated between 1.5 and 2 years, 3 stabilized and 3 were among those with signs of radiographic loosening. Fifteen patients (15 hips) revealed pain reduction at the 5-year follow-up. Three had slight pain on walking that disappeared immediately at rest (pain score 4). All the others revealed either no pain (pain score 6) or slight pain that disappeared with activity (pain score 5). No pattern of early socket migration according to radiostereometric analysis could be identified, predicting later socket migration or loosening. The rate of cases with signs of radiographic loosening (29%, 5/17) was comparable to that reported by the Nijmegen group but the follow-up was shorter in the current study. The rate of cases with signs of radiographic loosening was comparable to both conventionally cemented socket revisions and cementless revisions. The future will show if further sockets loosen and if the loose sockets up to date will end up in rerevisions.

Quality of life after hip revision with impaction bone grafting on a par with that 4 years after primary cemented arthroplasty.

BACKGROUND: There have been few studies evaluating patient-reported quality of life outcomes after hip revision with impaction bone grafting. PATIENTS AND METHODS: The inclusion criteria were aseptic loosening after primary arthroplasty performed for osteoarthrosis, and first-time revision with impacted morselized allograft bone and cemented Exeter stem. During a 4-year period, 35 patients were eligible and all were included. The Nottingham Health Profile (NHP) was completed by the patients and the Charnley hip scores recorded by the examining surgeon preoperatively, after 6 months and yearly up to 4 years (28 patients) postoperatively. For comparison, 35 osteoarthrotic patients completed the NHP 4 years after cemented Exeter primary arthroplasty. RESULTS: At 4 years, the NHP scores for the revision patients did not differ significantly from those recorded in the primary arthroplasty group. Among the revision patients, mixed model analysis showed improvement in NHP pain (p < 0.001) and physical mobility scores (p = 0.002). The effect size at 4 years was large for pain (1.2) and moderate for physical mobility (0.6). The major improvement was recorded at 6 months, with no further substantial change observed. The correlations between the NHP and Charnley scores were weak or moderate (r, -0.15 to -0.67). INTERPRETATION: Hip revision with impaction bone grafting leads to substantially improved quality of life, similar to that 4 years after primary arthroplasty.

Infection and arthritis. Infection of prosthetic joints.

Infection of prosthetic joints is one of the most devastating complications following replacement surgery. The size of the problem, the diagnostic puzzle, bacteriological findings and treatment modalities are highlighted.

Hip revision with impacted morselized allografts: unrestricted weight-bearing and restricted weight-bearing have similar effect on migration. A radiostereometry analysis.

BACKGROUND: No consensus exists as to whether to let patients bear weight or not after revision of a loosened hip prosthesis using morselized and impacted allograft bone and cement. In the original description of the method, the patients were advised not to bear weight for 3 months postoperatively. Theoretically, bone graft remodeling is enhanced by mechanical load, but an increased migration of the prosthesis within the graft can also be anticipated. In addition, practicing restricted weight-bearing is cumbersome for the patients. METHODS: The present study was initiated to evaluate the migration, as measured by radiostereometry analysis (RSA), in patients mobilized with unrestricted weight-bearing after a hip revision using the X-change Revision Instruments System. This group was compared with a previous series with restricted weight-bearing for the initial 3 months postoperatively. Seven stems and 12 sockets were evaluated by RSA over 2 years. Only patients without intraoperative complications were mobilized with unrestricted weight-bearing. RESULTS: All 7 stems migrated in the distal direction (median 2.6 mm; range 0.8-16.5 mm) and in the posterior direction (median 2.3 mm; range 0.7-22.1 mm). Eleven of the 12 sockets migrated in the proximal direction (median 2.5 mm; range 0.2-8.1 mm). The migration rate decreased gradually in all directions, but 3 stems and 5 sockets still migrated between the 1.5- and 2-year follow-ups. There were no significant differences in migration in any direction for either the stems or the sockets compared to the group with restricted weight-bearing. CONCLUSION: No increased migration occurred in the group free to bear weight as compared to restricted weight-bearing. We shall continue to allow unrestricted weight-bearing in cases where the femoral bone feels competent to withstand the initial load. It simplifies the postoperative mobilization, and we speculate that it might increase the remodeling of the graft.