The use of antibiotic-loaded bone cement and systemic antibiotic prophylactic use in 2,971,357 primary total knee arthroplasties from 2010 to 2020: an international register-based observational study among countries in Africa, Europe, North America, and Oceania.

BACKGROUND AND PURPOSE: Antibiotic-loaded bone cement (ALBC) and systemic antibiotic prophylaxis (SAP) have been used to reduce periprosthetic joint infection (PJI) rates. We investigated the use of ALBC and SAP in primary total knee arthroplasty (TKA). PATIENTS AND METHODS: This observational study is based on 2,971,357 primary TKAs reported in 2010-2020 to national/regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, the Netherlands, New Zealand, Norway, Romania, South Africa, Sweden, Switzerland, the UK, and the USA. Aggregate-level data on trends and types of bone cement, antibiotic agents, and doses and duration of SAP used was extracted from participating registries. RESULTS: ALBC was used in 77% of the TKAs with variation ranging from 100% in Norway to 31% in the USA. Palacos R+G was the most common (62%) ALBC type used. The primary antibiotic used in ALBC was gentamicin (94%). Use of ALBC in combination with SAP was common practice (77%). Cefazolin was the most common (32%) SAP agent. The doses and duration of SAP used varied from one single preoperative dosage as standard practice in Bolzano, Italy (98%) to 1-day 4 doses in Norway (83% of the 40,709 TKAs reported to the Norwegian arthroplasty register). CONCLUSION: The proportion of ALBC usage in primary TKA varies internationally, with gentamicin being the most common antibiotic. ALBC in combination with SAP was common practice, with cefazolin the most common SAP agent. The type of ALBC and type, dose, and duration of SAP varied among participating countries.

Have the Causes of Revision for Total and Unicompartmental Knee Arthroplasties Changed During the Past Two Decades?

BACKGROUND: Revisions after knee arthroplasty are expected to increase, and the epidemiology of failure mechanisms is changing as new implants, technology, and surgical techniques evolve. QUESTIONS/PURPOSES: (1) Was there improvement in survival for TKA and unicompartmental knee arthroplasty (UKA) when comparing two consecutive 11-year periods with similar followups in a national registry? (2) Were there changes in the causes of revision during the two times? (3) Could the changes in revision causes be attributed to patient or implant characteristics? METHODS: A total of 60,623 TKAs (2426 revisions) and 7648 UKAs (725 revisions) were selected from the Norwegian Arthroplasty Register and analyzed based on year of primary surgery: 1994 to 2004 (Period 1) and 2005 to 2015 (Period 2). TKAs had median followup of 3.5 years in Period 1 and 4.2 years in Period 2. Median followup for UKAs was 2.7 years in Period 1 and 4.6 years in Period 2. Of the patients included in the registry, 99.6% were accounted for at the time of analysis, whereas 0.4% had moved abroad. We used Kaplan-Meier analyses and log-rank test to investigate changes in survival. Relative risk of revision in Period 2 relative to Period 1 was calculated for each registered revision cause in a Cox regression model adjusted for age, sex, diagnosis, fixation, and patella resurfacing. RESULTS: For TKAs, the 10-year Kaplan-Meier survival free from revision improved from Period 1 to Period 2 from 91% (95% CI, 90%-92%) to 94% (95% CI, 94%-95%; p < 0.001). Revisions resulting from aseptic loosening of the femoral component, polyethylene wear/breakage, patellar dislocation, and unexplained pain decreased, whereas revisions resulting from early infection increased. Patients in Period 2 were younger and more often men compared with patients in Period 1. A higher risk of revision was found for male sex (relative risk [RR], 1.1; 95% CI, 1.0-1.2; p = 0.048) and age younger than 65 years (RR, 1.7; 95% CI, 1.6-1.9; p < 0.001). With UKAs, the 10-year survival free from revision was 80% (95% CI, 76%-84%) in Period 1 and 81% (95% CI, 79%-83%; p = 0.261) in Period 2. Revisions resulting from tibial aseptic loosening, polyethylene wear/breakage, and periprosthetic fractures decreased, but there were more revisions resulting from progression of osteoarthritis. In Period 2, there were more men and the average age was younger than for patients in Period 1. For UKAs, age younger than 65 years had a higher risk of revision (RR, 1.7; 95% CI, 1.5-2.0; p < 0.001), whereas sex did not affect the risk of revision. CONCLUSIONS: We found an improvement in survival free from revision for TKA in the last period, but no similar improvement for UKA, and the survivorship for UKAs remains rather dramatically lower than that observed for TKAs. The decision to perform a UKA should be made with the explicit awareness that its survivorship is substantially inferior to that of TKA; any perceived advantages of UKA should be balanced against this issue of its decreased durability. LEVEL OF EVIDENCE: Level III, therapeutic study.

Increased risk of aseptic loosening for 43,525 rotating-platform vs. fixed-bearing total knee replacements.

Background and purpose - Given similar functional outcomes with mobile and fixed bearings, a difference in survivorship may favor either. This study investigated the risk of aseptic loosening for the most used subtypes of mobile-bearing rotating-platform knees, in Norway and Australia. Patients and methods - Primary TKRs reported to the Norwegian and Australian joint registries, between 2003 and 2014, were analyzed with aseptic loosening as primary end-point and all revisions as secondary end-point. We hypothesized that no difference would be found in the rate of revision between rotating-platform and the most used fixed-bearing TKRs, or between keeled and non-keeled tibia. Kaplan-Meier estimates and curves, and Cox regression relative risk estimates adjusted for age, sex, and diagnosis were used for comparison. Results - The rotating-platform TKRs had an increased risk of revision for aseptic loosening compared with the most used fixed-bearing knees, in Norway (RR =6, 95% CI 4-8) and Australia (RR =2.1, 95% CI 1.8-2.5). The risk of aseptic loosening as a reason for revision was highest in Norway compared with Australia (RR =1.7, 95% CI 1.4-2.0). The keeled tibial component had the same risk of aseptic loosening as the non-keeled tibia (Australia). Fixation method and subtypes of the tibial components had no impact on the risk of aseptic loosening in these mobile-bearing knees. Interpretation - The rotating-platform TKRs in this study appeared to have a higher risk of revision for aseptic loosening than the most used fixed-bearing TKRs.

Secondary patella resurfacing in painful non-resurfaced total knee arthroplasties : A study of survival and clinical outcome from the Norwegian Arthroplasty Register (1994-2011).

PURPOSE: In Norway, 19 % of revisions of non-resurfaced total knee arthroplasties done for knee pain between 1994 and 2011 were Secondary Patella Resurfacing (SPR). It is, however, unclear whether SPR actually resolves the pain. The aim was to investigate prostheses survival and clinical outcomes following SPR. METHOD: A total of 308 knees (301 patients) with SPR were used to assess implant survival, and a sub-cohort (n = 114 out of 301 patients) with Patient Reported Outcome Measures (PROMs) data were used to assess the clinical outcomes. The EuroQol (EQ-5D), the Knee Injury and Osteoarthritis Outcome Score, and Visual Analogue Scales on satisfaction and pain were used to collect PROM data. Outcomes were analysed by Kaplan-Meier, Cox regression, and multiple linear regression. RESULTS: The five- and ten-year Kaplan-Meier survival percentages were 91 % and 87 %, respectively. Overall, 35 knees were re-revised at a median follow-up of eight years and pain alone (10 knees) was the main cause of re-revision. Younger patients (<60 years) had nearly nine times higher risk of re-revision compared to older patients (>70 years) (RR = 8.6; p < 0.001). Mean EQ-5D index score had improved from 0.41 (SD 0.21) preoperative to 0.56 (SD 0.25) postoperative following SPR. A total of 63 % of patients with PROM data were satisfied with the outcomes of SPR. CONCLUSION: The long-term prostheses survival following SPR was satisfactory, although not as good as for primary knee replacement. Patients' health related quality of life improved significantly following SPR. Still, more than a third of patients with PROMs data were dissatisfied with the outcomes of the SPR procedure.

Failure of aseptic revision total knee arthroplasties.

BACKGROUND AND PURPOSE: In Norway, the proportion of revision knee arthroplasties increased from 6.9% in 1994 to 8.5% in 2011. However, there is limited information on the epidemiology and causes of subsequent failure of revision knee arthroplasty. We therefore studied survival rate and determined the modes of failure of aseptic revision total knee arthroplasties. METHOD: This study was based on 1,016 aseptic revision total knee arthroplasties reported to the Norwegian Arthroplasty Register between 1994 and 2011. Revisions done for infections were not included. Kaplan-Meier and Cox regression analyses were used to assess the survival rate and the relative risk of re-revision with all causes of re-revision as endpoint. RESULTS: 145 knees failed after revision total knee arthroplasty. Deep infection was the most frequent cause of re-revision (28%), followed by instability (26%), loose tibial component (17%), and pain (10%). The cumulative survival rate for revision total knee arthroplasties was 85% at 5 years, 78% at 10 years, and 71% at 15 years. Revision total knee arthroplasties with exchange of the femoral or tibial component exclusively had a higher risk of re-revision (RR = 1.7) than those with exchange of the whole prosthesis. The risk of re-revision was higher for men (RR = 2.0) and for patients aged less than 60 years (RR = 1.6). INTERPRETATION: In terms of implant survival, revision of the whole implant was better than revision of 1 component only. Young age and male sex were risk factors for re-revision. Deep infection was the most frequent cause of failure of revision of aseptic total knee arthroplasties.

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.

Kaplan-Meier and Cox Regression Are Preferable for the Analysis of Time to Revision of Joint Arthroplasty: Thirty-One Years of Follow-up for Cemented and Uncemented THAs Inserted From 1987 to 2000 in the Norwegian Arthroplasty Register.

BACKGROUND: Previous studies have suggested that the probability function of 1 minus the Kaplan-Meier survivorship overestimates revision rates of implants and that patient death should be included in estimates as a competing risk factor. The present study aims to demonstrate that this line of thinking is incorrect and is a misunderstanding of both the Kaplan-Meier method and competing risks. METHODS: This study demonstrated the differences, misunderstandings, and interpretations of classical, competing-risk, and illness-death models with use of data from the Norwegian Arthroplasty Register for 15,734 cemented and 7,867 uncemented total hip arthroplasties (THAs) performed from 1987 to 2000, with fixation as the exposure variable. RESULTS: The mean age was higher for patients who underwent cemented (72 years) versus uncemented THA (53 years); as such, a greater proportion of patients who underwent cemented THA had died during the time of the study (47% compared with 29%). The risk of revision at 20 years was 18% for cemented and 42% for uncemented THAs. The cumulative incidence function at 20 years was 11% for cemented and 36% for uncemented THAs. The prevalence of revision at 20 years was 6% for cemented and 31% for uncemented THAs. CONCLUSIONS: Adding death as a competing risk will always attenuate the probability of revision and does not correct for dependency between patient death and THA revision. Adjustment for age and sex almost eliminated differences in risk estimates between the different regression models. In the analysis of time until revision of joint replacements, classical survival analyses are appropriate and should be advocated. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Outcome of Revision Surgery for Infection After Total Knee Arthroplasty: Results of 3 Surgical Strategies.

BACKGROUND: Periprosthetic joint infection (PJI) after knee arthroplasty surgery remains a serious complication, yet there is no international consensus regarding the surgical treatment of PJI. This study aimed to assess prosthesis survival rates, risk of revision, and mortality rate following different surgical strategies (1-stage versus 2-stage implant revision and irrigation and debridement with implant retention) that are used to treat PJI. METHODS: The study was based on 644 total knee arthroplasties (TKAs) that were revised because of a deep infection (i.e., surgically treated PJI) and reported to the Norwegian Arthroplasty Register (NAR) from 1994 to 2016. Kaplan-Meier and multiple Cox regression analyses were performed to assess implant survival rate and risk of revision. We also studied mortality rates at 90 days and 1 year after revision for PJI. RESULTS: During the follow-up period, 19% of the irrigation and debridement cases, 14% of the 1-stage revision cases, and 12% of the 2-stage revision cases underwent a subsequent revision because of a PJI. The 5-year Kaplan-Meier survival rate with revision for infection as the end point was 79% after irrigation and debridement, 87% after 1-stage revision, and 87% after 2-stage revision. There were no significant differences between 1-stage and 2-stage revisions with subsequent revision for any reason as the end point (relative risk [RR], 1.7; 95% confidence interval [CI], 0.9 to 3.5) and no difference with revision because of infection as the end point (RR, 1.6; 95% CI, 0.7 to 3.7). In an age-stratified analysis, however, the risk of revision for any reason was 4 times greater after 1-stage revision than after 2-stage revision in patients over the age of 70 years (RR, 4.3; 95% CI, 1.3 to 14.8). Age had no significant effect on the risk of subsequent revision for knees that had been revised with the irrigation and debridement procedure. The 90-day and 1-year mortality rates after revision for PJI were 1.2% and 2.5%, respectively. CONCLUSIONS: Irrigation and debridement yielded good results compared with previous published studies. Although the 1-stage revisions resulted in a fourfold increase in risk of subsequent revision compared with the 2-stage revisions in older patients, the overall outcomes after 1-stage and 2-stage revisions were similar. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Outcomes of Unicompartmental Knee Arthroplasty After Aseptic Revision to Total Knee Arthroplasty: A Comparative Study of 768 TKAs and 578 UKAs Revised to TKAs from the Norwegian Arthroplasty Register (1994 to 2011).

BACKGROUND: The general recommendation for a failed primary unicompartmental knee arthroplasty (UKA) is revision to a total knee arthroplasty (TKA). The purpose of the present study was to compare the outcomes, intraoperative data, and mode of failure of primary UKAs and primary TKAs revised to TKAs. METHODS: The study was based on 768 failed primary TKAs revised to TKAs (TKA→TKA) and 578 failed primary UKAs revised to TKAs (UKA→TKA) reported to the Norwegian Arthroplasty Register between 1994 and 2011. Patient-reported outcome measures (PROMs) including the EuroQol EQ-5D, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and visual analog scales assessing satisfaction and pain were used. We performed Kaplan-Meier and Cox regression analyses adjusting for propensity score to assess the survival rate and the risk of re-revision and multiple linear regression analyses to estimate the differences between the two groups in mean PROM scores. RESULTS: Overall, 12% in the UKA→TKA group and 13% in the TKA→TKA group underwent re-revision between 1994 and 2011. The ten-year survival percentage of UKA→TKA versus TKA→TKA was 82% versus 81%, respectively (p = 0.63). There was no difference in the overall risk of re-revision for UKA→TKA versus TKA→TKA (relative risk [RR] = 1.2; p = 0.19), or in the PROM scores. However, the risk of re-revision was two times higher for TKA→TKA patients who were greater than seventy years of age at the time of revision (RR = 2.1; p = 0.05). A loose tibial component (28% versus 17%), pain alone (22% versus 12%), instability (19% versus 19%), and deep infection (16% versus 31%) were major causes of re-revision for UKA→TKA versus TKA→TKA, respectively, but the observed differences were not significant, with the exception of deep infection, which was significantly greater in the TKA→TKA group (RR = 2.2; p = 0.03). The surgical procedure of TKA→TKA took a longer time (mean of 150 versus 114 minutes) and more of the procedures required stems (58% versus 19%) and stabilization (27% versus 9%) compared with UKA→TKA. CONCLUSIONS: Despite TKA→TKA seeming to be a technically more difficult surgical procedure, with a higher percentage of re-revisions due to deep infection compared with UKA→TKA, the overall outcomes of UKA→TKA and TKA→TKA were similar.