Risk factors for revision due to prosthetic joint infection following total knee arthroplasty based on 62,087 knees in the Finnish Arthroplasty Register from 2014 to 2020.

BACKGROUND AND PURPOSE: Periprosthetic joint infection (PJI) is the commonest reason for revision after total knee arthroplasty (TKA). We assessed the risk factors for revision due to PJI following TKA based on the Finnish Arthroplasty Register (FAR). PATIENTS AND METHODS: We analyzed 62,087 primary condylar TKAs registered between June 2014 and February 2020 with revision for PJI as the endpoint. Cox proportional hazards regression was used to estimate hazard ratios (HR) with 95% confidence intervals (CI) for the first PJI revision using 25 potential patient- and surgical-related risk factors as covariates. RESULTS: 484 knees were revised for the first time during the first postoperative year because of PJI. The HRs for revision due to PJI in unadjusted analysis were 0.5 (0.4-0.6) for female sex, 0.7 (0.6-1.0) for BMI 25-29, and 1.6 (1.1-2.5) for BMI > 40 compared with BMI < 25, 4.0 (1.3-12) for preoperative fracture diagnosis compared with osteoarthritis, and 0.7 (0.5-0.9) for use of an antimicrobial incise drape. In adjusted analysis the HRs were 2.2 (1.4-3.5) for ASA class III-IV compared with class I, 1.7 (1.4-2.1) for intraoperative bleeding ≥ 100 mL, 1.4 (1.2-1.8) for use of a drain, 0.7 (0.5-1.0) for short duration of operation of 45-59 minutes, and 1.7 (1.3-2.3) for long operation duration > 120 min compared with 60-89 minutes, and 1.3 (1.0-1.8) for use of general anesthesia. CONCLUSION: We found increased risk for revision due to PJI when no incise drape was used. The use of drainage also increased the risk. Specializing in performing TKA reduces operative time and thereby also the PJI rate.

Trends in Revision Hip Arthroplasty for Prosthetic Joint Infection: A Single-Center Study of 423 Hips at a High-Volume Center Between 2008 and 2021.

BACKGROUND: Prosthetic joint infection (PJI) is one of the most devastating complications after total hip arthroplasty (THA), and comorbidities increase the risk. We examined whether there was a temporal change in the demographics, especially regarding comorbidities, of patients who have PJIs and were treated over a 13-year study period at a high-volume academic joint arthroplasty center. In addition, the surgical methods used and the microbiology of the PJIs were assessed. METHODS: Revisions (n = 423, 418 patients) due to PJI of the hip performed at our institution between 2008 and September 2021 were identified. All included PJIs fulfilled the 2013 International Consensus Meeting diagnostic criteria. The surgeries were categorized into one of the following categories: debridement, antibiotics, and implant retention, 1-stage revision, and 2-stage revision. Infections were classified as early, acute hematogenous, and chronic infections. RESULTS: There was no change in the median age of the patients, but the proportion of ASA-class 4 patients increased from 10.5% to 20%. The incidence of early infections increased from 0.11 per 100 primary THAs in 2008 to 1.09 in 2021. The incidence of 1-stage revisions increased the most, rising from 0.10 per 100 primary THAs in 2010 to 0.91 per 100 primary THAs in 2021. Furthermore, the proportion of infections caused by Staphylococcus aureus increased from 26.3% in 2008 to 2009 to 40% in 2020 to 2021. CONCLUSION: The comorbidity burden of PJI patients increased during the study period. This increase may present a treatment challenge, as comorbidities are known to have a negative effect on PJI treatment outcomes.

Risk factors for prosthetic joint infections following total hip arthroplasty based on 33,337 hips in the Finnish Arthroplasty Register from 2014 to 2018.

Background and purpose - Periprosthetic joint infection (PJI) is a devastating complication and more information on risk factors for PJI is required to find measures to prevent infections. Therefore, we assessed risk factors for PJI after primary total hip arthroplasty (THA) in a large patient cohort.Patients and methods - We analyzed 33,337 primary THAs performed between May 2014 and January 2018 based on the Finnish Arthroplasty Register (FAR). Cox proportional hazards regression was used to estimate hazard ratios with 95% confidence intervals (CI) for first PJI revision operation using 25 potential patient- and surgical-related risk factors as covariates.Results - 350 primary THAs were revised for the first time due to PJI during the study period. The hazard ratios for PJI revision in multivariable analysis were 2.0 (CI 1.3-3.2) for ASA class II and 3.2 (2.0-5.1) for ASA class III-IV compared with ASA class I, 1.4 (1.1-1.7) for bleeding > 500 mL compared with < 500 mL, 0.4 (0.2-0.7) for ceramic-on-ceramic bearing couple compared with metal-on-polyethylene and for the first 3 postoperative weeks, 3.0 (1.6-5.6) for operation time of > 120 minutes compared with 45-59 minutes, and 2.6 (1.4-4.9) for simultaneous bilateral operation. In the univariable analysis, hazard ratios for PJI revision were 2.3 (1.7-3.3) for BMI of 31-35 and 5.0 (3.5-7.1) for BMI of > 35 compared with patients with BMI of 21-25.Interpretation - We found several modifiable risk factors associated with increased PJI revision risk after THA to which special attention should be paid preoperatively. In particular, high BMI may be an even more prominent risk factor for PJI than previously assessed.

Periprosthetic Femoral Fracture Is a Leading Cause of Early Revision With Taper-Slip Stems in Primary Total Hip Arthroplasty: An Analysis of 2765 Total Hip Arthroplasties From a High-Volume Hospital.

BACKGROUND: In 2016, the CPT stem replaced the Exeter stem as the main cemented stem at our institution. We assessed the prevalence of revision for periprosthetic femoral fracture (PFF) in patients operated on with either CPT or Exeter stem and compared the risk for revision between these stems. METHODS: Primary total hip arthroplasties either performed in 2012-2015 with Exeter stem (n = 1443) or in 2017-2018 with CPT stem (n = 1322) were included. The prevalence of revision for PFF was compared. The Kaplan-Meier estimated survivorships were calculated for the 2 stem designs. The risk for revision was analyzed using the Cox proportional hazard regression model. RESULTS: At 2 years, PFF was the most common reason for revision in the study population (1.3% prevalence, comprising 35% of all revisions). Moreover, 1.6% (95% confidence interval [CI] 1.0-2.4) of the CPT and 1.0% (95% CI 0.6-1.6) of the Exeter stems had been revised due to PFF. The 3-year Kaplan-Meier probability estimates for all-cause revision were 4.8% for the CPT (95% CI 3.6-6.0) and 3.3% for the Exeter stem (95% CI 2.3-4.3). The hazard ratio for revision due to any reason was 1.1 (95% CI 0.3-3.8) during the first 2 weeks, and 1.8 (95% CI 1.2-2.7, P = .006) from 2 weeks onwards for the CPT compared with the Exeter stem. CONCLUSION: The considerable number of PFF revisions with taper-slip stems, especially with CPT stems, is a matter of concern. Alternative cemented stems should be considered in patients at high risk for PFF.

Preoperative Risk Prediction Models for Short-Term Revision and Death After Total Hip Arthroplasty: Data from the Finnish Arthroplasty Register.

Because of the increasing number of total hip arthroplasties (THAs), even a small proportion of complications after the operation can lead to substantial individual difficulties and health-care costs. The aim of this study was to develop simple-to-use risk prediction models to assess the risk of the most common reasons for implant failure to facilitate clinical decision-making and to ensure long-term survival of primary THAs. METHODS: We analyzed patient and surgical data reported to the Finnish Arthroplasty Register (FAR) on 25,919 primary THAs performed in Finland between May 2014 and January 2018. For the most frequent adverse outcomes after primary THA, we developed multivariable Lasso regression models based on the data of the randomly selected training cohort (two-thirds of the data). The performances of all models were validated using the remaining, independent test set consisting of 8,640 primary THAs (one-third of the data) not used for building the models. RESULTS: The most common outcomes within 6 months after the primary THA were revision operations due to periprosthetic joint infection (1.1%), dislocation (0.7%), or periprosthetic fracture (0.5%), and death (0.7%). For each of these outcomes, Lasso regression identified subsets of variables required for accurate risk predictions. The highest discrimination performance, in terms of area under the receiver operating characteristic curve (AUROC), was observed for death (0.84), whereas the performance was lower for revisions due to periprosthetic joint infection (0.68), dislocation (0.64), or periprosthetic fracture (0.65). CONCLUSIONS: Based on the small number of preoperative characteristics of the patient and modifiable surgical parameters, the developed risk prediction models can be easily used to assess the risk of revision or death. All developed models hold the potential to aid clinical decision-making, ultimately leading to improved clinical outcomes. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Posterior approach, fracture diagnosis, and american society of anesthesiology class iii-iv are associated with increased risk of revision for dislocation after total hip arthroplasty: An analysis of 33,337 operations from the finnish arthroplasty register.

BACKGROUND AND OBJECTIVE: Dislocation is one of the most common reasons for revision surgery after primary total hip arthroplasty. Both patient related and surgical factors may influence the risk of dislocation. In this study, we evaluated risk factors for dislocation revision after total hip arthroplasty based on revised data contents of the Finnish Arthroplasty Register. METHODS: We analyzed 33,337 primary total hip arthroplasties performed between May 2014 and January 2018 in Finland. Cox proportional hazards regression was used to estimate hazard ratios with 95% confidence intervals for first dislocation revision using 18 potential risk factors as covariates, such as age, sex, diagnosis, hospital volume, surgical approach, head size, body mass index, American Society of Anesthesiology class, and fixation method. RESULTS: During the study period, there were 264 first-time revisions for dislocation after primary total hip arthroplasty. The hazard ratio for dislocation revision was 3.1 (confidence interval 1.7-5.5) for posterior compared to anterolateral approach, 3.0 (confidence interval 1.9-4.7) for total hip arthroplasties performed for femoral neck fracture compared to total hip arthroplasties performed for osteoarthritis, 2.0 (confidence interval 1.0-3.9) for American Society of Anesthesiology class III-IV compared to American Society of Anesthesiology class I, and 0.5 (0.4-0.7) for 36-mm femoral head size compared to 32-mm head size. CONCLUSIONS: Special attention should be paid to patients with fracture diagnoses and American Society of Anesthesiology class III-IV. Anterolateral approach and 36-mm femoral heads decrease dislocation revision risk and should be considered for high-risk patients.

Increased risk for dislocation after introduction of the Continuum cup system: lessons learnt from a cohort of 1,381 THRs after 1-year follow-up.

Background and purpose - The introduction of new total hip replacements (THRs) is known to be associated with an increased risk for complications. On completion of a competitive procurement process, a new uncemented cup system was introduced into general use at our institution in 2016. We launched this study after the introduction to assess (1) the incidence of early dislocations of the old (Pinnacle) and the new (Continuum) cup systems, and (2) whether the cup design would affect the risk for dislocation.Patients and methods - We assessed the incidence of dislocations after 1,381 primary THRs performed at our institution during 2016. Also, the effect of the cup system (Pinnacle, Continuum with neutral liner, Continuum with elevated rim liner) on dislocation rates was analyzed using a multivariable regression model.Results - 47 (3.4%) early dislocations were identified. The incidence of dislocations was 1.3% for the Pinnacle, 5.1% for the Continuum with neutral liner, and 1.2% for the Continuum with elevated rim liner. The Continuum with neutral liner was found to have an increased risk for dislocations compared with the Pinnacle (aOR 5, 95% CI 1.4-17). However, when an elevated rim liner was used with the Continuum, the risk for dislocation between the Continuum and the Pinnacle was similar.Interpretation - Our results emphasize the need for both careful consideration before the introduction of new implants and the systematic monitoring of early outcomes thereafter. The elevated rim liner should be preferred for use with the Continuum cup because of the poor coverage of the neutral liner that may result in dislocations.

Declining Revision Burden of Metal-on-Metal Hip Arthroplasties.

BACKGROUND: Adverse reactions to metal debris (ARMD) have been a problem with metal-on-metal (MoM) hip systems for a decade. Unacceptably high revision rates have been described for both stemmed MoM total hip arthroplasties (THAs) and hip resurfacings. The aim of this study was to report survivorship and temporal trends of hip revisions in patients with MoM hips. METHODS: We identified 2520 patients with 3013 MoM hip arthroplasties performed at our institution. These included 1532 primary stemmed MoM THAs, 1262 MoM hip resurfacings, and 219 stemmed MoM THAs implanted in revision surgery. RESULTS: Revision surgery was performed on 551 (36%) primary stemmed MoM THAs and on 179 (14%) resurfacings. The most common reason for revision was ARMD both among primary MoM THAs (83%) and hip resurfacings (70%). The 15-year implant survivorship was 69% (95% confidence interval [CI] 67-71%) for the whole study group, 56% (CI 53-60%) for stemmed primary MoM THAs, and 84% (CI 82-87%) for hip resurfacings. Clear temporal peak in the number of revisions for ARMD was seen in 2011-2013, and the trend has been decreasing since. CONCLUSION: After a decade since outburst of the ARMD problematics with MoM hips, a large proportion of them have gone through revision surgery at our single high-volume center. The peak years were 2011-2013, and thereafter, the number of ARMD revisions has decreased every year. With the threshold for revision remaining constant at our institution, it is not likely that large amount of new cases of ARMD will be seen. As these results are derived from a single center's data, similar studies from other institutions are needed to see whether our results represent a global trend.

Effect of Bearing Type on Taper Material Loss in Hips From 1 Manufacturer.

BACKGROUND: Numerous studies have reported on clinical significant volumes of material loss and corrosion at the head-stem junction of metal-on-metal (MOM) hips; less is understood about metal-on-polyethylene (MOP) hips. We compared the effect of bearing type (MOM vs MOP) on taper material loss for a hip system of a single design. METHODS: In this cohort study, we recruited retrieved MOM (n = 30) and MOP (n = 22) bearing hips that were consecutively received at our center. We prospectively collected associated clinical and imaging data. We measured the severity of corrosion and volumes of material loss at each head taper surface and used multivariate statistical analysis to investigate differences between the 2 bearing types. RESULTS: The median rate of material loss for the MOM and MOP groups was 0.81 mm3/y (0.01-3.45) and 0.03 mm3/y (0-1.07), respectively (P < .001). Twenty-nine of 30 MOM hips were revised for adverse metal reactions, compared with 1 of 22 MOP hips. CONCLUSION: MOP hips lost significantly less material from their taper junctions than MOM hips. Our results can reassure patients with MOP Pinnacle hips that they are unlikely to experience clinically significant problems related to material loss from the taper junction.

Chronic Kidney Diseases Among Patients Undergoing Elective Arthroplasty: Risk Groups and the Value of Serum Creatinine.

BACKGROUND: In arthroplasty clinics, we tend to evaluate patient's kidney function looking at serum creatinine (SCr), while estimated glomerular filtration rate (eGFR) is recommended. We reported the prevalence of chronic kidney disease (CKD; eGFR <60 mL/min/1.73 m2) in different patient groups and investigated whether CKD is missed by evaluation based on SCr. METHODS: Preoperative SCr values were used to calculate eGFR in 20,575 consecutive hip or knee arthroplasties. RESULTS: Prevalence of CKD was 9%-12%. It was higher among older women, knee arthroplasty patients, and patients with hypertension, diabetes, or coronary disease. Using SCr instead of eGFR leads to missing CKD in up to 7% of the cases. In older women and older patients with body mass index <25 kg/m2, half of CKD cases were missed. CONCLUSION: Use of eGFR instead of SCr to detect CKD more accurately is recommended.

Factors Associated With Trunnionosis in the Metal-on-Metal Pinnacle Hip.

BACKGROUND: Trunnionosis of the tapered head-stem junction of total hip arthroplasties, either through corrosion or mechanical wear, has been implicated in early implant failure. Retrieval analysis of large numbers of failed implants can help us better understand the factors that influence damage at this interface. METHODS: In this study, we examined 120 retrieved total hip arthroplasties of one bearing design, the 36-mm diameter metal-on-metal, DePuy Pinnacle, that had been paired with 3 different stems. We measured material loss of the bearing and head-trunnion taper surfaces and collected clinical and component data for each case. We then used multiple linear regression analysis to determine which factors influenced the rate of taper material loss. RESULTS: We found 4 significant variables: (1) longer time to revision (P = .004), (2) the use of a 12/14 taper for the head-trunnion junction (P < .001), (3) decreased bearing surface wear (P = .003), and (4) vertical femoral offset (P = .05). These together explained 29% of the variability in taper material loss. CONCLUSION: Our most important finding is the effect of trunnion design. Of the 3 types studied, we found that S-ROM design was the most successful at minimizing trunnionosis.

Higher Blood Cobalt and Chromium Levels in Patients With Unilateral Metal-on-Metal Total Hip Arthroplasties Compared to Hip Resurfacings.

BACKGROUND: Adverse soft tissue reactions in metal-on-metal (MoM) hip replacements are associated with cobalt (Co) and chromium (Cr) ions in blood. We report the prevalence and risk factors for elevated blood Co and Cr levels in patients with a unilateral MoM hip. METHODS: From a single institution, blood Co and Cr levels were analyzed in 1748 patients (692 hip resurfacings and 1056 total hip arthroplasties [THAs]). Concentrations exceeding 7 ppb were considered elevated, and the risk factors for elevated levels were calculated with binary logistic regression. RESULTS: Elevated blood metal ion levels were more common in MoM THA than in resurfacing patients (17.4% vs 5.9%, P < .001), and in 5 of the 7 THA brands, more than 20% of patients had elevated metal ion concentrations, whereas the proportion was less than 10% in all hip resurfacings. In resurfacings, small femoral head (odds ratio [OR] 1.30 per millimeter decrease [CI, 1.12-1.49]), high acetabular inclination (OR 1.15 per degree increase [CI 1.09-1.22]), and young age (OR 1.05 per year decrease [1.02-1.10]) were independent risk factors for elevated ions. In the THA group, female gender (OR 2.04 [CI 1.35-3.06]), longer time between surgery and ion measurement (OR 1.19 per year increase [CI 1.05-1.34]), and large headsize (OR 1.07 per millimeter increase [CI 1.01-1.13]) were risk factors for elevated ions. CONCLUSION: Given the high percentage of elevated levels, the systematic surveillance of especially large diameter MoM THAs seems justified.