Editorial: Management of PJI/SSI after joint arthroplasty.

The management of periprosthetic joint infection (PJI) and surgical site infection (SSI) after joint arthroplasty poses a major challenge in orthopedic surgery. This Editorial provides an overview of the studies published in the special issue "Management of PJI/SSI after Joint Arthroplasty", summarizing the key findings from these studies, which cover a wide range of topics, including stringent preventive strategies, comprehensive diagnostic methods, and personalized treatment modalities. The authors concluded the editorial with their perspectives regarding the status quo of research in this field and future directions for research, such as the development of novel antibiotics, biofilm research, patient-specific risk factors, and the integration of technological advancements (such as machine learning and artificial intelligence) into clinical practice. The authors emphasized the need for continued research, interdisciplinary collaboration, and the application of innovative technologies to enhance patient outcomes and mitigate the burden of these infections on healthcare systems.

Time trends in case-mix and risk of revision following hip and knee arthroplasty in public and private hospitals: a cross-sectional analysis based on 476,312 procedures from the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: This study aims to assess time trends in case-mix and to evaluate the risk of revision and causes following primary THA, TKA, and UKA in private and public hospitals in the Netherlands. METHODS: We retrospectively analyzed 476,312 primary arthroplasties (public: n = 413,560 and private n = 62,752) implanted between 2014 and 2023 using Dutch Arthroplasty Register data. We explored patient demographics, procedure details, trends over time, and revisions per hospital type. Adjusted revision risk was calculated for comparable subgroups (ASA I/II, age ≤ 75, BMI ≤ 30, osteoarthritis diagnosis, and moderate-high socioeconomic status (SES). RESULTS: The volume of THAs and TKAs in private hospitals increased from 4% and 9% in 2014, to 18% and 21% in 2022. Patients in private hospitals were younger, had lower ASA classification, lower BMI, and higher SES compared with public hospital patients. In private hospitals, age and ASA II proportion increased over time. Multivariable Cox regression demonstrated a lower revision risk for primary THA (HR 0.7, CI 0.7-0.8), TKA (HR 0.8, CI 0.7-0.9), and UKA (HR 0.8, CI 0.7-0.9) in private hospitals. After initial arthroplasty in private hospitals, 49% of THA and 37% of TKA revisions were performed in public hospitals. CONCLUSION: Patients in private hospitals were younger, had lower ASA classification, lower BMI, and higher SES com-pared with public hospital patients. The number of arthroplasties increased in private hospitals, with a lower revision risk compared with public hospitals.

Low revision rate throughout the adoption of the direct superior approach in primary total hip arthroplasty: an analysis based on 1551 total hip arthroplasties from the Dutch Arthroplasty Register.

BACKGROUND: Recently, surgeons introduced a minimally invasive modification on the classic posterolateral approach (PLA) in total hip arthroplasty (THA): the direct superior approach (DSA). We investigated the association between surgeon's experience and the risk of early revision of the DSA in primary THA, using data from the Dutch Arthroplasty Register (LROI). METHODS: We retrieved all primary THAs performed using the DSA in 4 hospitals between 2016 and 2022 (n = 1551). Procedures were sorted in 5 groups using the date of operation and number of previous procedures per surgeon: 1-25; 26-50; 51-75; 76-100; >100. Subsequently, data from different surgeons were pooled together and the risk of revision was calculated via a multilevel time-to-event analysis. RESULTS: The overall revision rate was 1.5% after a mean follow-up of 2 years. Patients from the 1-25 group had comparable risks of revision compared to patients in the >100 group (hazard ratio [HR] 1.0 [CI, 0.3-3.2]). The risk for patients in groups 26-50, 51-75 and 75-100 was also not statistically different from the >100 group (resp. HR 1.5 [CI, 0.5-5.0], 1.8 [CI, 0.5-6.4] and 0.5 [CI, 0.1-4.0]). Main reasons of revision were dislocation (0.5%) and infection (0.4%). CONCLUSIONS: We did not identify an association between the surgeon's experience and the early risk of revision for the DSA in primary THA in the Netherlands. The DSA seems safe in the early adoption phases with a low risk of revision due to dislocation and revision for all other causes.

Machine Learning Did Not Outperform Conventional Competing Risk Modeling to Predict Revision Arthroplasty.

BACKGROUND: Estimating the risk of revision after arthroplasty could inform patient and surgeon decision-making. However, there is a lack of well-performing prediction models assisting in this task, which may be due to current conventional modeling approaches such as traditional survivorship estimators (such as Kaplan-Meier) or competing risk estimators. Recent advances in machine learning survival analysis might improve decision support tools in this setting. Therefore, this study aimed to assess the performance of machine learning compared with that of conventional modeling to predict revision after arthroplasty. QUESTION/PURPOSE: Does machine learning perform better than traditional regression models for estimating the risk of revision for patients undergoing hip or knee arthroplasty? METHODS: Eleven datasets from published studies from the Dutch Arthroplasty Register reporting on factors associated with revision or survival after partial or total knee and hip arthroplasty between 2018 and 2022 were included in our study. The 11 datasets were observational registry studies, with a sample size ranging from 3038 to 218,214 procedures. We developed a set of time-to-event models for each dataset, leading to 11 comparisons. A set of predictors (factors associated with revision surgery) was identified based on the variables that were selected in the included studies. We assessed the predictive performance of two state-of-the-art statistical time-to-event models for 1-, 2-, and 3-year follow-up: a Fine and Gray model (which models the cumulative incidence of revision) and a cause-specific Cox model (which models the hazard of revision). These were compared with a machine-learning approach (a random survival forest model, which is a decision tree-based machine-learning algorithm for time-to-event analysis). Performance was assessed according to discriminative ability (time-dependent area under the receiver operating curve), calibration (slope and intercept), and overall prediction error (scaled Brier score). Discrimination, known as the area under the receiver operating characteristic curve, measures the model's ability to distinguish patients who achieved the outcomes from those who did not and ranges from 0.5 to 1.0, with 1.0 indicating the highest discrimination score and 0.50 the lowest. Calibration plots the predicted versus the observed probabilities; a perfect plot has an intercept of 0 and a slope of 1. The Brier score calculates a composite of discrimination and calibration, with 0 indicating perfect prediction and 1 the poorest. A scaled version of the Brier score, 1 - (model Brier score/null model Brier score), can be interpreted as the amount of overall prediction error. RESULTS: Using machine learning survivorship analysis, we found no differences between the competing risks estimator and traditional regression models for patients undergoing arthroplasty in terms of discriminative ability (patients who received a revision compared with those who did not). We found no consistent differences between the validated performance (time-dependent area under the receiver operating characteristic curve) of different modeling approaches because these values ranged between -0.04 and 0.03 across the 11 datasets (the time-dependent area under the receiver operating characteristic curve of the models across 11 datasets ranged between 0.52 to 0.68). In addition, the calibration metrics and scaled Brier scores produced comparable estimates, showing no advantage of machine learning over traditional regression models. CONCLUSION: Machine learning did not outperform traditional regression models. CLINICAL RELEVANCE: Neither machine learning modeling nor traditional regression methods were sufficiently accurate in order to offer prognostic information when predicting revision arthroplasty. The benefit of these modeling approaches may be limited in this context.

The Direct Superior Approach in Total Hip Arthroplasty: A Systematic Review.

BACKGROUND: Evolution of the surgical approach for total hip arthroplasty (THA) has led to the development of the minimally invasive direct superior approach (DSA). It is hypothesized that the DSA reduces postoperative pain and hospital length of stay (LOS). We aimed to provide an overview of current evidence on clinical, functional, and radiological outcomes with respect to risk of revision, complications, pain scores, physical function, operative time, LOS, blood loss, radiological outcomes, and learning curve. METHODS: A comprehensive search of Medline, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar, reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses literature search extension guidelines, was conducted to identify studies evaluating clinical, functional, and radiological outcomes of the DSA. Quality assessment was performed using the Cochrane Risk of Bias tool and Newcastle-Ottawa Scale. The review protocol was prospectively registered in the International Prospective Registry of Systematic Reviews. RESULTS: Seventeen studies were included, generally of moderate quality. Qualitative synthesis evidenced accurate implant positioning, short LOS, and a short learning curve. Conflicting findings were reported for postoperative complications compared with conventional approaches. Better functional outcomes were seen in the early postoperative period than the posterolateral approach (PLA). Outcomes such as blood loss and operative time exhibited conflicting results and considerable heterogeneity. CONCLUSION: Based on moderate-certainty evidence, it is uncertain if the DSA provides short-term advantages over conventional approaches such as PLA. There is limited evidence on long-term outcomes post-THA using the DSA. Further studies and ongoing registry monitoring is crucial for continuous evaluation of its long-term outcomes. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

The Rise of the Direct Anterior Approach: Trends, Learning Curves, and Patient Characteristics of 63,182 Primary Total Hip Arthroplasties in the Dutch Arthroplasty Register (LROI).

BACKGROUND: The use of the direct anterior approach (DAA) in total hip arthroplasty (THA) has steadily increased in the Netherlands since 2007. The aim of this study was to outline how the DAA has been implemented in the Netherlands. Moreover, we investigated the learning curve of the DAA at a hospital level, and explored patient characteristics of the DAA compared with other approaches and during the learning phase after implementing the DAA. METHODS: In this population-based cohort study, we included all primary THAs between 2007 and 2020 (n = 342,473) from the Dutch Arthroplasty Register. For hospitals implementing the DAA (n > 20), patients were categorized in 4 experience groups using the date of surgery: 1 to 50, 51 to 100, 101 to 150, or > 150. Subsequently, data from different hospitals were pooled and survival rates were calculated using Kaplan-Meier survival analyses. Adjusted revision rates were calculated using mixed Cox proportional hazard models (frailty). RESULTS: The use of the DAA gradually rose from 0.2% in 2007 to 41% of all primary THAs in 2020. A total of 64 (56%) hospitals implemented the DAA. However, not all hospitals continued using this approach. After implementation, the 5-year survival rate for the first 50 procedures was significantly lower (96% confidence interval [CI] 95.8 to 97.2) compared to >150 procedures (98% CI 97.7 to 98.1). Multivariable Cox hazard analyses demonstrated a higher risk of revision during the first 50 procedures compared with >150 procedures (hazard ratio 1.6, CI 1.3 to 2.0). CONCLUSIONS: The use of DAA for primary THA significantly increased. For hospitals implementing DAA, a considerable learning curve with increased revision risk was seen.

Femoral Neck Design Does Not Impact Revision Risk After Primary Total Hip Arthroplasty Using a Dual Mobility Cup.

Background: The use of dual mobility (DM) cups has increased quickly. It is hypothesized that femoral neck taper geometry may be involved in the risk of prosthetic impingement and DM cup revision. We aim to (1) explore the reasons for revision of DM cups or head/liners and (2) explore whether certain femoral neck characteristics are associated with a higher risk of revision of DM cups. Methods: Primary total hip arthroplasties with a DM cup registered in the Dutch Arthroplasty Register between 2007 and 2021 were identified (n = 7603). Competing risk survival analyses were performed, with acetabular component and head/liner revision as the primary endpoint. Reasons for revision were categorized in cup-/liner-related revisions (dislocation, liner wear, acetabular loosening). Femoral neck characteristics were studied to assess whether there is an association between femoral neck design and the risk of DM cup/liner revision. Multivariable Cox proportional hazard analyses were performed. Results: The 5- and 10-year crude cumulative incidence of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was 0.5% (CI 0.4-0.8) and 1.9% (CI 1.3-2.8), respectively. After adjusting for confounders, we found no association between the examined femoral neck characteristics (alloy used, neck geometry, CCD angle, and surface roughness) and the risk for revision for dislocation, wear, and acetabular loosening. Conclusions: The risk of DM cup or head/liner revision for dislocation, wear, and acetabular loosening was low. We found no evidence that there is an association between femoral neck design and the risk of cup or head/liner revision.

Positive Intraoperative Cultures in Cup Revisions of THA: What Happens to the Stem?

BACKGROUND: Positive intraoperative cultures (PICs) are encountered in some patients undergoing revision of the acetabular cup after a previous THA. It is unknown whether PIC of the cup indicates whether the stem is infected as well and what happens to the stem during follow-up. QUESTIONS/PURPOSES: (1) What proportion of patients undergoing THA who undergo cup revision have PICs? (2) What is the survival of the stem during follow-up in cup revisions with PICs versus that of those with negative cultures? (3) Does antibiotic treatment of PIC of the cup prevent revision THA during follow-up? METHODS: In this retrospective, comparative multicenter study, five surgeons at four centers performed 338 acetabular cup revisions between January 2015 and December 2017. After evaluating the data, we excluded one patient because of an incomplete dataset and 77 patients because fewer than three intraoperative cultures were obtained during surgery, leaving 260 patients for analysis. Follow-up was 2 years. Patients were stratified into three cohorts: no PIC, one PIC, and two or more PICs. RESULTS: The proportion of patients with one or more PIC was 15% (39 of 260). A total of 8% (21 of 260) had one and 7% (18 of 260) had two or more PICs. Stem survival was lower in patients with two or more PICs, but stem revision for periprosthetic joint infection was similar between groups. Two-year survival, which was defined as freedom from revision for any cause or infection, was 97% (95% confidence interval 95% to 99%) in the group without PICs, 100% (95% CI 95% to 100%) in the group with one PIC, and 86% (95% CI 68% to 100%; p = 0.08) in the group with two or more PICs. None of the patients in the no PIC and one PIC groups were treated with antibiotics. In the two or more PICs cohort, 12 of 18 patients were treated. The stem survived in one of 12 patients treated with antibiotics versus two of six patients who were not treated with antibiotics. CONCLUSION: When treated with antibiotics, more than two PICs isolated during cup revision surgery do not have a major impact on survival of the stem during follow-up. A larger cohort of patients with PICs during cup revision might confirm these findings. LEVEL OF EVIDENCE: Level III, therapeutic study.

No clinically relevant difference in patient-reported outcomes between the direct superior approach and the posterolateral or anterior approach for primary total hip arthroplasty: analysis of 37,976 primary hip arthroplasties in the Dutch Arthroplasty Registry.

BACKGROUND AND PURPOSE: The direct superior approach (DSA) is a modification of the posterolateral approach (PLA) for total hip arthroplasty (THA). Patient-reported outcome measures (PROMs) of the DSA have not been investigated previously using nationwide data. Our aim was to assess PROMs after THA using the DSA compared with the PLA and, secondarily, with the anterior approach (DAA). PATIENTS AND METHODS: In this population-based cohort study we included 37,976 primary THAs performed between 2014 and 2020 (PLA: n = 22,616; DAA: n = 15,017; DSA: n = 343) using Dutch Arthroplasty Registry data. PROMs (NRS pain, EQ-5D, HOOS-PS, and OHS) were measured preoperatively, and at 3 and 12 months postoperatively. Repeated measurements were analyzed using mixed-effects models, adjusted for confounders, to investigate the association between surgical approach and PROMs over time. RESULTS: From baseline to 3 and 12 months, improvements for NRS pain scores, EQ-5D, and OHS were comparable for the DSA compared with the PLA or DAA. No difference was found in HOOS-PS improvement 3 months postoperatively between DSA and PLA (-0.2, 95% confidence interval [CI] -2.4 to 1.9) and between DSA and DAA (-1.7, CI -3.9 to 0.5). At 12 months postoperatively, patients in the DSA group had improved -2.8 points (CI -4.9 to -0.6) more in HOOS-PS compared with the DAA, but not with the PLA group (-1.0, CI -3.2 to 1.1). CONCLUSION: Our study showed no clinically meaningful differences between the DSA and either PLA or DAA.

Similar revision rate after cemented and cementless femoral revisions for periprosthetic femoral fractures in total hip arthroplasty: analysis of 1,879 revision hip arthroplasties in the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: Periprosthetic femoral fracture (PPF) after total hip arthroplasty (THA) is a serious complication, as it often is followed by functional deficits and morbidity. There is no consensus regarding the optimal stem fixation method and whether additional cup replacement is beneficial. The aim of our study was to perform a direct comparison of reasons and risk of re-revision between cemented and uncemented revision THAs following PPF using registry data. PATIENTS AND METHODS: 1,879 patients registered in the Dutch Arthroplasty Registry (LROI) who underwent a first-time revision for PPF between 2007 and 2021 (cemented stem: n = 555; uncemented stem: n = 1,324) were included. Competing risk survival analysis and multivariable Cox proportional hazard analyses were performed. RESULTS: 5- and 10-year crude cumulative incidence of re-revision following revision for PPF was similar between cemented (resp. 13%, 95% CI 10-16 and 18%, CI 13-24) and uncemented (resp. 11%, CI 10-13 and 13%, CI 11-16) revisions. Multivariable Cox regression analysis, adjusting for potential confounders, showed a similar risk of revision for uncemented and cemented revision stems. Finally, we found no difference in risk of re-revision between a total revision (HR 1.2, 0.6-2.1) compared with a stem revision. CONCLUSION: We found no difference in the risk of re-revision between cemented and uncemented revision stems after revision for PPF.

Revision risk by using the direct superior approach (DSA) for total hip arthroplasty compared with postero-lateral approach: early nationwide results from the Dutch Arthroplasty Register (LROI).

BACKGROUND AND PURPOSE: The direct superior approach (DSA) is a modification of the classic posterolateral approach (PLA) for total hip arthroplasty (THA), in which the iliotibial band and short external rotators are spared. The revision rate of the DSA has not been investigated previously using arthroplasty registry data. We examined the reasons and risk of revision of the DSA, compared with the direct anterior approach (DAA) and PLA. PATIENTS AND METHODS: In this population-based cohort study we included 175,543 primary THAs performed between 2014 and 2020 (PLA, n = 117,576; DAA, n = 56,626; DSA, n = 1,341). Competing risk survival analysis and multivariable Cox proportional hazard analyses, adjusted for potential confounders, were performed. RESULTS: After 3 years, crude revision rates due to any reason were 2.1% (95% confidence interval [CI] 1.3-3.3) for DSA, and 2.9% (CI 2.8-3.0) for PLA. Crude dislocation revision rates were 0.3% (CI 0.1-0.8) for DSA, versus 1.0% (CI 0.9-1.0) for PLA. Dislocation revision rate for DSA did not differ from DAA (0.3% [CI 0.2-0.3]). Multivariable Cox regression analysis demonstrated no overall difference in revision rates for the DSA (HR 0.6 [CI 0.4-1.09) compared with the PLA. Lower risk of revision due to dislocation was found in patients operated on through the DSA (HR 0.3 [0.1-0.9]) compared with the PLA. CONCLUSION: Early nationwide results suggest that the DSA for total hip arthroplasty seems to show a tendency towards a lower risk of revision for dislocation but no overall reduced revision risk compared with the PLA.

Femoral head size and surgical approach affect dislocation and overall revision rates in total hip arthroplasty: up to 9-year follow-up data of 269,280 procedures in the Dutch Arthroplasty Register (LROI).

BACKGROUND: Femoral head size and surgical approach might affect the revision rate for dislocation and for any other reason after total hip arthroplasty (THA). We penetrated this question based on registry data with up to 9-year follow-up. METHODS: 269,280 primary THAs documented in the Dutch Arthroplasty Registry (LROI) between 2007 and 2019 were included. Revision rates were calculated by competing risk analyses. Multivariable Cox proportional hazard regression ratios (HR) were used for comparison. RESULTS: Revisions for dislocation were rare. They were more frequent after posterolateral (1.4% [95% CI, 1.3-1.5]), compared to straight lateral (0.6% [95% CI, 0.5-0.7]), anterolateral (0.6% [95% CI, 0.5-0.7]) and anterior (0.4% [95% CI, 0.3-0.5]) approach. Larger femoral head size decreased the dislocation revision risk: 1.4% [95% CI, 1.3-1.5) for 22-28-mm heads; 0.9% (95% CI, 0.8-1.0) for 32-mm heads; 0.6% (95% CI, 0.6-0.7) for 36-mm heads. For the anterior approach, the HR for both revision for dislocation (0.3, 95% CI, 0.3-0.4) and any other reason (0.8, 95% CI, 0.8-0.9) were lowest compared to other approaches including posterolateral (HR 1). Revision risk for any other reason was highest with anterolateral (HR 1.3 (95% CI, 1.2-1.4)) and straight lateral approach (1.1 [95% CI, 1.0-1.2]). CONCLUSIONS: The anterior approach might reduce revision rates for both dislocation and all cause revision. Posterolateral approach is associated with a higher risk of dislocation revision but has a lower risk of any other revision. Increasing femoral head size up to 36 mm reduces revision for dislocation and improves overall revision rates for all approaches.

The learning curve of the direct anterior approach is 100 cases: an analysis based on 15,875 total hip arthroplasties in the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: In the last decade, the direct anterior approach (DAA) for total hip arthroplasty (THA) has become more popular in the Netherlands. Therefore, we investigated the learning curve and survival rate of the DAA in primary THA, using data from the Dutch Arthroplasty Register (LROI). PATIENTS AND METHODS: We identified all patients who received a primary THA using the DAA in several high-volume centers in the Netherlands between 2007 and 2019 (n = 15,903). Procedures were ordered per surgeon, using date of operation. Using the procedure number, operations were divided into 6 groups based on the number of previous procedures per surgeon (first 25, 26-50, 51-100, 101-150, 151-200, > 200). Data from different surgeons in different hospitals was pooled together. Revision rates were calculated using a multilevel time-to-event analysis. RESULTS: Patients operated on in group 1-25 (hazard ratio [HR] 1.6; 95% CI 1.1-2.4) and 26-50 (HR 1.6; CI 1.1-2.5) had a higher risk for revision compared with patients operated on in group > 200 THAs. Between 50 and 100 procedures the revision risk was increased (HR 1.3; CI 0.9-1.9), albeit not statistically significant. From 100 procedures onwards the HR for revision was respectively 1.0 (CI 0.6-1.6) and 0.8 (CI 0.5-1.4) for patients in operation groups 101-150 and 151-200. Main reasons for revision were loosening of the stem (29%), periprosthetic infection (19%), and dislocation (16%). INTERPRETATION: We found a 64% increased risk of revision for patients undergoing THA using the DAA for the first 50 cases per surgeon. Between 50 and 100 cases, this risk was 30% increased, but not statistically significant. From 100 cases onwards, a steady state had been reached in revision rate. The learning curve for DAA therefore is around 100 cases.

[Assessing radiological images: is twice always better?] / Beoordeling van radiologische beelden.

In current practice, radiological diagnostics are often assessed by both the referring clinician as well as the radiologist. Specific medical specialists like pulmonologists and orthopaedic surgeons make treatment decisions mostly on their own expertise and interpretation of radiological images, before the radiological report is available. For health care as a whole, a single assessment gives efficiency gains, and the radiologist is not disturbed by getting rid of 'bulk' and can focus on the more complex matter in which he or she is indispensable. Regular multidisciplinary meetings may serve to jointly assess images about which there is ambiguity. Combining clinical information and radiological expertise then leads to optimisation of both quality and efficiency. It makes sense and is efficient to have clinicians with specific radiological expertise, such as pulmonologists and orthopaedists, assess certain radiological examinations independently, allowing the radiologist to concentrate on more complex imaging.

If, When, and How to Use Rifampin in Acute Staphylococcal Periprosthetic Joint Infections, a Multicentre Observational Study.

BACKGROUND: Rifampin is generally advised in the treatment of acute staphylococcal periprosthetic joint infections (PJI). However, if, when, and how to use rifampin remains a matter of debate. We evaluated the outcome of patients treated with and without rifampin, and analyzed the influence of timing, dose and co-antibiotic. METHODS: Acute staphylococcal PJIs treated with surgical debridement between 1999 and 2017, and a minimal follow-up of 1 year were evaluated. Treatment failure was defined as the need for any further surgical procedure related to infection, PJI-related death or the need for suppressive antimicrobial treatment. RESULTS: A total of 669 patients were analyzed. Treatment failure was 32.2% (131/407) in patients treated with rifampin and 54.2% (142/262) in whom rifampin was withheld (P < .001). The most prominent effect of rifampin was observed in knees (treatment failure 28.6% versus 63.9%, respectively, P < .001). The use of rifampin was an independent predictor of treatment success in the multi-variate analysis (OR 0.30, 95% CI 0.20 - 0.45). In the rifampin group, the use of a co-antibiotic other than a fluoroquinolone or clindamycin (OR 10.1, 95% CI 5.65 - 18.2) and the start of rifampin within 5 days after surgical debridement (OR 1.96, 95% CI 1.08 - 3.65) were predictors of treatment failure. The dosing of rifampin had no effect on outcome. CONCLUSIONS: Our data supports the use of rifampin in acute staphylococcal PJIs treated with surgical debridement, particularly in knees. Immediate start of rifampin after surgical debridement should probably be discouraged, but requires further investigation.

Which patients improve most after total hip arthroplasty? Influence of patient characteristics on patient-reported outcome measures of 22,357 total hip arthroplasties in the Dutch Arthroplasty Register.

BACKGROUND: Patient-reported outcome measures (PROMs) after total hip arthroplasty (THA), can be influenced by patient characteristics (case-mix factors). We used the Dutch Arthroplasty Register (LROI) to determine the effect of case-mix on improvement of PROMs after primary THA. METHODS: We included all primary THAs (n = 22,357) performed in the Netherlands between 2014 and 2018. The Hip disability and Osteoarthritis Outcome Score Physical function short form (HOOS-PS), Oxford Hip Score (OHS), EQ-5D index score and thermometer, and Numeric Rating Scales (NRS) measuring pain during activities and at rest, were recorded. The difference between preoperative and 3- and 12-month postoperative scores was calculated (delta-PROM) and used as primary outcome variable. Multivariable linear regression was used to examine the association between patient characteristics (age, sex, ASA score, body mass index (BMI), Charnley class, smoking, and previous operations to the affected hip) and PROMs. Cohens' d was used to measure effect size. RESULTS: Postoperative improvement (delta-PROM) on HOOS-PS, OHS, EQ-5D, and pain relief were significantly higher in patients <60 years, in patients with female gender, a high ASA score (III-IV), a BMI >30 kg/m2, and patients without a previous operation to the hip. Cohen's d indicated clinically small differences (0.2). CONCLUSIONS: Patients benefiting most in terms of postoperative improvement of self-reported physical functioning, pain relief and quality of life after primary THA were young, female, with a high ASA or BMI score, and without previous operations to the hip.

Effectiveness of a Home-Based Rehabilitation Program After Total Hip Arthroplasty Driven by a Tablet App and Remote Coaching: Nonrandomized Controlled Trial Combining a Single-Arm Intervention Cohort With Historical Controls.

BACKGROUND: Recent technological developments such as wearable sensors and tablets with a mobile internet connection hold promise for providing electronic health home-based programs with remote coaching for patients following total hip arthroplasty. It can be hypothesized that such a home-based rehabilitation program can offer an effective alternative to usual care. OBJECTIVE: The aim of this study was to determine the effectiveness of a home-based rehabilitation program driven by a tablet app and remote coaching for patients following total hip arthroplasty. METHODS: Existing data of two studies were combined, in which patients of a single-arm intervention study were matched with historical controls of an observational study. Patients aged 18-65 years who had undergone total hip arthroplasty as a treatment for primary or secondary osteoarthritis were included. The intervention consisted of a 12-week home-based rehabilitation program with video instructions on a tablet and remote coaching (intervention group). Patients were asked to do strengthening and walking exercises at least 5 days a week. Data of the intervention group were compared with those of patients who received usual care (control group). Effectiveness was measured at four moments (preoperatively, and 4 weeks, 12 weeks, and 6 months postoperatively) by means of functional tests (Timed Up & Go test and the Five Times Sit-to Stand Test) and self-reported questionnaires (Hip disability and Osteoarthritis Outcome Score [HOOS] and Short Form 36 [SF-36]). Each patient of the intervention group was matched with two patients of the control group. Patient characteristics were summarized with descriptive statistics. The 1:2 matching situation was analyzed with a conditional logistic regression. Effect sizes were calculated by Cohen d. RESULTS: Overall, 15 patients of the intervention group were included in this study, and 15 and 12 subjects from the control group were matched to the intervention group, respectively. The intervention group performed functional tests significantly faster at 12 weeks and 6 months postoperatively. The intervention group also scored significantly higher on the subscales "function in sport and recreational activities" and "hip-related quality of life" of HOOS, and on the subscale "physical role limitations" of SF-36 at 12 weeks and 6 months postoperatively. Large effect sizes were found on functional tests at 12 weeks and at 6 months (Cohen d=0.5-1.2), endorsed by effect sizes on the self-reported outcomes. CONCLUSIONS: Our results clearly demonstrate larger effects in the intervention group compared to the historical controls. These results imply that a home-based rehabilitation program delivered by means of internet technology after total hip arthroplasty can be more effective than usual care. TRIAL REGISTRATION: ClinicalTrials.gov NCT03846063; https://clinicaltrials.gov/ct2/show/NCT03846063 and German Registry of Clinical Trials DRKS00011345; https://tinyurl.com/yd32gmdo.