Introduction. The epidemiology of re-revision total hip arthroplasty (THA) is not well understood. The purpose of this study is to investigate the epidemiology of re-revision THA, and identify risk factors that are associated with failure of re-revision THA. Methods. A retrospective analysis was performed on 288 patients who underwent revision THA at a single institution between 1/2012 and 12/2013. Patients who underwent revision hip arthroplasty two or more times were included. Patients were excluded if their indication for their first revision was due to periprosthetic joint infection (PJI). Patient demographics, surgical indications, revision details, and available follow-up information were collected through the electronic medical record. Re-revision failure was defined as the need for any additional return to the operating room, regardless of indication. A logistic regression analysis was performed to assess for significant predictors of re-revision failure. Results. A total of 51 re-revision patients were included in this study. Mean age at re-revision was 59.6 (±14.2 years). There were 32 (67%) females. Mean BMI was 28.8 (±5.4). Median ASA level was 2 (23; 55%). The median number of revisions was 3 (range 2–11). The most common indication for re-revision was acetabular component loosening (15; 29%), followed by PJI (13; 25%) and instability (9; 18%). Among re-revision patients, the most common indication of the first revision was acetabular component loosening (11; 27%), followed by polyethylene wear (8; 19%) and instability (8; 19%) (Figure 1). There was a significantly increased risk of re-revision failure if the re-revision procedure involved exchanging only the head and polyethylene liner (RR=1.792; p=0.017), if instability was the indication for the first revision (RR=3.000; p<0.001), as well as if instability was the indication for the re-revision (RR=1.867; p=0.038). If only the femoral component was exchanged during the re-revision, there was a decreased risk of failure (RR=0.268, p=0.046). 1-year re-revision survival was 54% (23/43). Discussion. Acetabular component loosening and PJI were the most common indications for re-revision. There was an increased risk of re-revision failure if instability was a cause for reoperation at any point during the revision history, or if only an isolated head and polyethylene liner exchange was indicated during the re-revision procedure. There was a decreased risk of re-revision failure if only an isolated femoral stem revision was performed. A better understanding of the indications and patient factors that are associated with re-revision failures can help align surgeon and patient expectations in this challenging population. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction. Revision Total Knee Arthroplasty (TKA) is becoming increasingly prevalent as the number of TKA procedures grow in a younger, higher-demand population. Factors associated with patients requiring multiple revision TKAs are not yet well understood. The purpose of this study is to investigate the epidemiology of re-revision TKA, and identify risk factors that are associated with failure of re-revision TKA. Methods. A retrospective analysis was performed on 358 patients who underwent revision TKA at a single institution between 1/2012 and 12/2013. Patients who underwent revision knee arthroplasty two or more times were included. Patients were excluded if their indication for the first revision was periprosthetic joint infection (PJI). Patient demographics, surgical indications, revision details, and available follow-up information were collected. Re-revision failure was defined as the need for any additional operative intervention. A logistic regression analysis was performed to assess for significant predictors of re-revision failure. Results. A total of 66 re-revision TKA patients were included in this study. Mean age at re-revision was 60 (±11 years). There were 48 (73%) females. Mean BMI was 31.8 (±6.9). Median ASA level was 2 (40/59; 68%). Average follow up was 2.1 (±1.0) years, with 68% (45/66) of patients having greater than 2 year follow up (Table 1). The median number of revisions was 2 (range 2–11). The most common indication for re-revision was arthrofibrosis (15; 23%), followed by PJI (14; 21%) and aseptic component loosening (13; 20%). Among re-revision patients, the most common indication of the first revision was aseptic component loosening (17; 30%), followed by arthrofibrosis (16; 28%) and instability (9; 16%) (Table 2). Among the top four indications for re-revision, both the re-revision and initial revision indication were the same. Additionally, 42% of patients possessed the same indication for re-revision as the initial revision. The proportion of patients that had a lateral release performed in either the index procedure or initial revision was higher in re-revisions performed for patellar maltracking (p=0.013). There was a significantly increased risk of re-revision failure if the patient had a higher BMI (OR=1.22; p=0.006). Re-revision survival at 30 days was 92% (60/65), at 1 year was 81% (52/64), and at 2 years 73% (33/45). The indication history of re-revision failure is shown on Table 3. Discussion. Arthrofibrosis and PJI were the most common indications for re-revision. There was an increased risk of re-revision failure in patients with a higher BMI. It was common to have a re-revision TKA for the same indication as the initial revision. A better understanding of the indications and patient factors that are associated with re-revision failures can help align surgeon and patient expectations in this challenging population. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Aim. It still remains unclear whether postoperative antibiotic treatment is advantageous in presumed aseptic revision-arthroplasties of the hip (rTHA) and knee (rTKA) with unexpected-positive-intraoperative-cultures (UPIC). The aim of this study was to evaluate if there is a difference in the septic and/or aseptic re-revision rate in patients with or without postoperative antibiotics. Method. In this retrospective propensity-score (PS) matched cohort-study we compared the re-revision rate and the microbiological spectrum in rTHA and rTKA treated with (AB-Group; n=70) and without (non-AB-Group; n=70) antibiotic treatment in patients with UPIC. Baseline covariates for PS-matching were type of revision, sex, Body-Mass-Index, age, Surgical-Site-Infection-Score, American-Society-of-Anesthesiologists-Classification, serum C-reactive-protein. All patients received routine antibiotic prophylaxis, but empiric AB treatment was started only in patients in the AB-Group. Post-operative treatment was decided on an individual basis according to the preference of the surgeon and the infectious disease specialist for a minimum duration of two weeks. In total, 90 rTHA (45 AB-Group, 45 in non-AB-Group) patients with UPICs and 50 rTKA (25 AB-Group, 25 in non-AB-Group) were included in the study. There was no significant variation in patient demographics. Results. After a median follow-up of 4.1 (IQR: 2.9-5.5) years after rTHA and rTKA, there was no higher re-revision rate (p=0.813) between the AB-group 10/70 (14.3%), and the non-AB-group 11/70 (15.7%). In the AB group, 4.3% (3/70) of patients underwent revision due to septic complications compared to 5.7% (4/70) in the non-AB group (survival log-rank: p=0.691). In total, 30/70 (42.9%) of patients in the AB-group and 23/70 (32.9%) of patients in the non-AB group were diagnosed as having an “infection likely” according to the PJI diagnostic criteria of EBJIS (p=0.223). All UPICs comprised low virulent microorganisms and were considered as a contaminant. In total, 68/70 (97.1%) of the patients in the AB-group received a dual antibiotic treatment for a mean duration of 41 (IQR: 23.5-56.5) days. Conclusion. Postoperative antibiotic treatment did not result in a decreased re-revision rate compared to non-antibiotic treatment in patients with UPIC in presumed aseptic rTHA and rTKA. UPICs with pathogens are likely to be a containment and therefore the classification of “infection likely” according to the EBJIS definition can be safely ignored

Aim. Debridement Antibiotics and Implant Retention(DAIR) is a procedure to treat a periprosthetic joint infection(PJI) after Total Hip Arthroplasty(THA) or Total Knee Arthroplasty(TKA). The timing between the primary procedure and the DAIR is likely a determinant for its successful outcome. There are few retrospective studies correlating timing of a DAIR with success (1,2). However, the optimal timing of a DAIR and the chance of success still remains unclear. We aimed to assess the risk of re-revision within one year after a DAIR procedure and to evaluate the timing of the DAIR in primary THA and TKA. An estimation of the chance of a successful DAIR will help clinicians and patients in their decision-making process in case of an acute postoperative PJI. Method. We used data from the Dutch Arthroplasty Register(LROI) and selected all primary THA and TKA in the period 2007–2016 who underwent a DAIR within 12 weeks after primary procedure. A DAIR was defined as a revision for infection in which only modular parts were exchanged. A DAIR was successful if not followed by a re-revision within 1 year after DAIR. The analyses were separated for THA and TKA procedures. Results. 207 DAIRs were performed <4 weeks after THA of which 41(20%) received a re-revision within 1 year; 87 DAIRs were performed between 4–8 weeks of which 15(17%) were re-revised and 11 DAIRs were performed >8 weeks and 2(18%) received a re-revision. 126 DAIRs were performed <4 weeks after TKA of which 27(21%) received a re-revision within 1 year; 68 DAIRs were performed between 4–8 weeks of which 14(21%) were re-revised and 15 DAIRs were performed >8 weeks and 3(20%) received a re-revision. Conclusions. There was no difference in 1-year re-revision rate after a DAIR procedure by timing of DAIR procedure for total hip and knee arthroplasty based on Dutch registry data

Aim

Aseptic loosening is the leading cause of revision of total hip arthroplasty (THA). It is well recognized that an occult infection is the underlying cause of some aseptic revisions. Intraoperative cultures are central to the diagnosis of prosthetic joint infection (PJI). However, the diagnostic and prognostic value of unexpected positive intraoperative cultures remains unclear.

The aim was to study whether first-time aseptic revision of a total hip arthroplasty with unexpected bacterial growth in cultures of intraoperatively taken biopsies have an increased risk of secondary revision due to all causes and increased risk of PJI revision, specifically.

Introduction. Acetabular component loosening with associated bone loss is a challenge in revision hip arthroplasty. Trabecular Metal (TM) by Zimmer Biomet has been shown to have greater implant survivorship for all-cause acetabular revision in small cohort retrospective studies. Our study aims to review outcomes of acetabular TM implants locally. Method. This is a retrospective observational study using data from Auckland City and North Shore Hospitals from 1st of January 2010 to 31st of December 2020. Primary outcome is implant survivorship (re-revision acetabular surgery for any cause) demonstrated using Kaplan-Meier analysis. Secondary outcome is indication for index revision and re-revision surgery. Multivariate analysis used to identify statistically significant factors for re-revision surgery. Results. 225 cases used acetabular TM implants (shells and/or augments) over 10 years. Indications include aseptic loosening (63%), instability (15%) and infection (13%). Of these, 12% (n=28) had further re-revision for infection (54%) and instability (21%). Median time to re-revision was 156 days (range 11 – 2022). No cases of re-revision were due to failure of bony ingrowth or acetabular component loosening. Ethnicity, smoking status, and age were not risk factors for re-revision procedures. Additionally, previous prosthetic joint infection, ethnicity, sex and age were not significant risk factors for re-revision due to infection. Implant survivorship was 80% at 1 year, 71% at 5 years and 64% at 10 years. Discussion. Main indications for re-revision were infection and instability. Demographic factors and co-morbidities did not correlate with increased re-revision risk. Survivorship is poorer compared to cumulative survivorship reported by the New Zealand Joint Registry (NZJR). Explanations are multifactorial and possibly contributed by underestimation of true revision rates by registry data. Conclusions. We need to identify alternate causes for poorer survivorship and review the role of TM implants in acetabular revision within our specified population

Aim. Aim was to compare revision rates when using single versus dual antibiotic loaded cement (ABLC) in hip fracture arthroplasty and aseptic revision hip or knee arthroplasty using data from the Dutch national joint registry (LROI). Methods. All primary cemented (hemi-)arthroplasties for acute hip fractures and cemented aseptic hip or knee revision arthroplasties, were incorporated in 3 datasets. All registered implants between 2007 and 2018 were included (minimum 2 years follow-up). Primary end-point was subsequent revision rates for infection and for any reason in the single and dual ABLC groups. Cumulative crude incidence of revision was calculated using competing risk analysis. Results. A total of 22,308 hip fracture arthroplasties, 2,529 hip revision and 7,124 knee revision arthroplasties were registered and analyzed in the study period. The majority of hip fracture patients (97.1%) was treated with single ABLC. For hip and knee revision arthroplasties dual ABLC was used in 33.8% and 25.7%. The revision rate for infection in the fracture arthroplasty group was not different between groups (0.5% versus 0.8%, p=0.27). The re-revision rate following hip or knee revision based on single versus dual ABLC was not different between groups (3.2% versus 2.8%, p=0.82 for hip revision and 1.8% versus 2.5%, p=0.36 for knee revision). In addition, the re-revision rate for any reason was not different in all three datasets. The crude cumulative revision and re-revision rates for any reason based on single ABLC versus dual ABLC showed no differences in all three datasets. The crude cumulative 7-year re-revision rate for any reason following revision THA with Gentamicin ABLC use was 11.8%, with Gentamicin + Clindamycin ABLC use 13.1% and with Erythromycin + Colistin ABLC use 14.8% (ns). The crude cumulative 9-year re-revision rate for any reason following revision TKA with Gentamicin ABLC use was 17.7% and with Gentamicin + Clindamycin ABLC use 16.5% (ns). Conclusions. In conclusion, we could not show a difference in revision rate for hip fracture arthroplasty or re-revision rates for revision hip- or knee arthroplasty with the use of dual ABLC compared to single ABLC bone cement, with 7and 9 year follow up. The low percentage of dual ABLC in hip fracture arthroplasties in our registry do not enable us to make a reliable estimation of the added value in this patient category. The results of this study do not confirm the potential benefit of dual ABLC use in revision cases

Aims. The aim of this study was to assess the incidence the microbiological spectrum and clinical outcome of hip and knee revision arthroplasties with unexpected-positive-intraoperative-cultures (UPIC) at a single center with minimum follow up of 2 years. Methods. We retrospectively analyzed our prospectively maintained institutional arthroplasty registry. Between 2011 and 2020 we performed presumably aseptic rTHA (n=939) and rTKA (n= 1,058). Clinical outcome, re-revision rates and causes as well as the microbiological spectrum were evaluated. Results. In total, 219/939 (23.3%) rTHA and 114/ 1,058 (10.8%) rTKA had a UPIC (p<0.001). Single positive intraoperative cultures were found in 173/219 (78.9%) in rTHA and 99/114 (86.8%) in rTKA, whereas 46/219 (21.0%) rTHA and 15/114 (13.2%) rTKA had positive results in ≥2 intraoperative cultures. A total of 390 microorganisms were found among the 333 cases. Staphylococcus epidermidis 30.9%, CoNS (21.9%), Cutibacterium acnes 21.1%, and Bacillus spp. 7.3% were the most common microorganisms. Overall, detected microorganisms showed high sensitivity to daptomycin (96.6%), vancomycin (97.3%) and linezolid (98.0%). After a minimum follow up of 2 years (rTHA 1,470 (735; 3,738) days; rTKA 1,474 (749; 4,055) days). During the 2-year follow-up, 8 patients died and 5 were lost to follow-up. There were 54/219 (24.7%) re-revision in rTHa and 20/114 (17.5%) in rTKA. Overall, there were 23 (10.5%) septic re-rTHA and 9 (7.9%) septic re-rTKA as well as 31 (14.2%) aseptic re-rTHA and 11 (9.6%) aseptic re-rTKA. Patients with previous septic revisions bevor UPIC procedure showed a significant higher risk for septic re-revision (p<0.05). Moreover, there were less septic re-revisions after single culture positive UPIC (rTHA: 16/173 (9.2%); rTKA 6/99 (6.1%)) compared to ≥2 positive intraoperative cultures UPIC (rTHA: 7/46 (15.2%); rTKA 3/15 (20.0%)). The most common reason for re-revision in the rTHA-group was aseptic loosening of the cup (34.2%) or of the stem (23.3%), dislocation (18.3%) and periprosthetic-fractures (7.8%). In the rTKA-group it was aseptic loosening (40.4%), instability (24.6%) and secondary patella resurfacing (7.9%). There was a higher septic re-revision rate in consecutive revisions than in planned revisions 17.3% vs. 8.5% in the rTHA-group and 14.3% vs. 7.5% in the rTKA-group, p<0.001. Conclusion. UPICs are common in rTJA. The rate was higher in hips which may partly explained by the easier pre op joint aspiration in the knee. UPIC may lead to an increase in subsequent re-revisions

Background. Obesity has been linked with increased rates of knee osteoarthritis. Limited information is available on the survival and functional outcome results of rTKR in the obese patients. This registry-based study aimed to identify whether BMI is an independent risk factor for poorer functional outcomes and /or implant survival in rTKA. Methods. New Zealand Joint Registry (NZJR) data of patients who underwent rTKA from 1st January 2010 to January 2023 was performed. Demographics, American Society of Anesthesiologists (ASA), BMI, Operative time, indications for revision and components revised of the patients undergoing rTKA was collected. Oxford knee score (OKS) at 6 months and rates of second revision (re- revision) were stratified based on standardised BMI categories. Results. Of the 2687 revisions, functional outcome scores were available for 1261 patients. Oxford knee scores following rTKA are significantly inferior in higher BMI patients (36.5 vs 31.5 p<0.001). This held true when adjusted for age (35.7 vs 30.9 p<0.001). Tibial component loosening was a more common indication for revision in patients with BMI >40 (31.1% vs 21% for BMI <25), whereas periprosthetic femoral fracture was significantly more commonly seen in patients with BMI <25. Re-revision rates displayed no significant differences between any pairs of BMI groups (2.18/100 component years) and adjusting for age and sex did not alter this (p= 0.462). Indications for re-revision were also not different between BMI categories. Over 50% of the rTKA patients were obese. Significantly more obese patients were ASA grade 3,4 and more were <75 years. Operative time was longer in the obese patients (p<0.001). Conclusions. Although overall re-revision rates are similar between all BMI categories, the functional outcomes favour those with lower BMI. Patients with higher BMI are younger, more comorbid and carry potentially higher perioperative risks. The registry data provides valuable information when providing counsel to patients undergoing rTKA and lends further support to optimising patients prior to pTKA

Aim. Our aim was to evaluate the prevalence and impact of unexpected intraoperative cultures on the outcome of total presumed aseptic knee and hip revision surgery. Method. Data regarding patients prospectively recruited in our center, who had undergone elective complete hip and knee revision surgery from January 2003 to July 2017 with a preoperative diagnosis of aseptic loosening was retrospectively reviewed. Partial revisions and patients with follow up below 60 months were excluded from the study. The protocol of revision included at least 3 intraoperative cultures. Failure was defined as the need for re-revision due to any-cause at 5 years and/or the need for antibiotic suppressive therapy. Results. A total of 608 cases were initially included in the study, 53 patients were excluded. 123 hip and 432 knee revision surgeries were included. 420 cases (75.7%) had all cultures negative, 114 (20.5%) a single positive culture or two of different microorganisms and 21 (3.8%) had at least 2 positive cultures for the same microorganism. Early failure was found in 4.8% (1/21) of the patients with missed low grade infection. The presence of positive cultures during total exchange was not associated with a higher failure rate than in those with negative cultures (44 of 420, 10.5%). In contrast, patients revised before 24 months had a significant higher rate of re-revision, 18% (15/83) vs. 8.4%. Conclusions. Total hip and knee revisions with unexpected positive cultures were not significantly associated with a higher re-revision risk at 5 years of follow-up. Representing an overall good prognosis. However, revision surgeries performed within the first 24 months have a higher rate of failure

Aim. Little is known about microbiological spectrum and resistance patterns as well as the clinical outcome in patients who undergo a repeat first stage procedure as part of a 2-stage revision arthroplasty for the treatment of periprosthetic hip and knee joint infections. Methods. Between 2011 and 2019, a total of 327 2-stage revision arthroplasties were performed on 312 patients with PJI of the knee and hip at our institution. We performed a retrospective analysis of all patients, who underwent a repeat first stage procedure regarding re-revision rate, host factors, culture negative and positive stages, monomicrobial and polymicrobial infections as well as microbiological spectrum and antimicrobial resistance patterns. Results. Overall, 52/312 (16.7%) patients (27 knee/25 hip) underwent a repeat first stage procedure. There were 35/52 (67.3%) culture positive first, 17/52 (32.7%) culture positive repeat first and 12/52 (23.1%) culture positive second stage procedures. In 13/52 (25%) patients a re-revision surgery was necessary at a median follow-up of 46.8 months (range, 12.2 to 93.3 months). High re-revision rates (10/12 [83.3%]) were found in patients with culture positive second stage and low re-revision rates (3/40 [7.5%]; p<0.01) were found in patients with culture negative second stage. The microbiological spectrum changed in 9/11 (81.8%) patients between culture positive first and repeat first stage, in 3/4 (75%) patients between culture positive repeat first and second stage and in 5/6 (83.3%) between culture positive second stage and subsequent re-revision surgery. Moreover, the antimicrobial resistance pattern changed in 6/9 (66.7%) of persistent microorganisms. Conclusion. Microbiological results during first, repeat first and second stage procedures significantly impacted the re-revision rates and changes in microbiological spectrum and resistance patterns between stages are common. However, if eradication of the microorganism at second stage can be accomplished, low re-revision rates can be achieved, even in patients who require a repeat first stage procedure

Aim. Analysis of microbiological spectrum and resistance patterns as well as the clinical outcome of patients who underwent a Debridement, antibiotics and implant retention (DAIR) procedure in the early phase following failed two-stage exchange arthroplasty of the knee and hip. Method. Of 312 patients treated with two-stage exchange arthroplasty between January 2011 and December 2019, 16 (5.1%) patients (9 knee, 7 hip) underwent a DAIR procedure within 6 months following second stage. We retrospectively analyzed the microbiological results as well as changes in the microbiological spectrum and antibiotic resistance patterns between stages of two-stage exchange arthroplasties and DAIR procedures. Patient's re-revision rates after a minimum follow-up of 12 months following DAIR procedure were evaluated. Moreover, differences between knee and hip and between infected primary total joint replacement (TJRs) and infected revision TJRs as well as patient's host factors and microbiological results regarding the outcome of DAIR were analyzed. Results. In 7/16 (43.8%) patients the first and second stage procedure was culture positive, in 5/16 (31.2%) patients the first and second stage procedure was culture negative and in 4/16 (25%) patients the first stage procedure was culture positive, and the second stage procedure was culture negative. Moreover, 6 (37.5%) out of 16 DAIR procedures showed a positive microbiological result. In 5/7 (71.4%) patients with culture positive second stage procedure a different microorganism compared to first stage procedure was detected. In 6/6 (100%) patients with culture positive DAIR procedure, the isolated microorganisms were not detected during first or second stage procedure. An additional re-revision surgery was necessary in 4/16 (25%) patients after a median time of 31 months (range, 12 to 138 months) at a mean follow up of 63.1 ± 32 months following DAIR procedure. Highest re-revision rates were found in patients with culture positive second stage procedures (3/7 [42.9%]) and patients with culture positive DAIR procedures (2/6 [33.3%]). Conclusions. DAIR procedure seems to be a useful early treatment option following failed two-stage exchange arthroplasty. The re-revision rates were independent of different combinations of culture positive and culture negative first and second stage procedures. The high number of changes in the microbiological spectrum needs to be considered in the treatment of PJI

The demand for revision total knee arthroplasty (TKA) has grown significantly in recent years. The two major fixation methods for stems in revision TKA include cemented and ‘hybrid’ fixation. We explore the optimal fixation method using data from recent, well-designed comparative studies. We performed a systematic review of comparative studies published within the last 10 years with a minimum follow-up of 24 months. To allow for missing data, a random-effects meta-analysis of all available cases was performed. The odds ratio (OR) for the relevant outcome was calculated with 95% confidence intervals. The effects of small studies were analyzed using a funnel plot, and asymmetry was assessed using Egger's test. The primary outcome measure was all-cause failure. Secondary outcome measures included all-cause revision, aseptic revision and radiographic failure. There was a significantly lower failure rate for hybrid stems when compared to cemented stems (p = 0.006) (OR 0.61, 95% CI 0.42-0.87). Heterogeneity was 4.3% and insignificant (p = 0.39). There was a trend toward superior hybrid performance for all other outcome measures including all-cause re-revision, aseptic re-revision and radiographic failure. Recent evidence suggests a significantly lower failure rate for hybrid stems in revision TKA. There is also a trend favoring the use of hybrid stems for all outcome variables assessed in this study. This is the first time a significant difference in outcome has been demonstrated through systematic review of these two modes of stem fixation. We therefore recommend the use, where possible, of hybrid stems in revision TKA

Introduction. Re-revision due to instability and dislocation can occur in up to 1 in 4 cases following revision total hip arthroplasty (THA). Optimal placement of components during revision surgery is thus critical in avoiding re-revision. Computer-assisted navigation has been shown to improve the accuracy and precision of component placement in primary THA; however, its role in revision surgery is less well documented. The purpose of our study was to evaluate the effect of computer-assisted navigation on component placement in revision total hip arthroplasty, as compared with conventional surgery. Methods. To examine the effect of navigation on acetabular component placement in revision THA, we retrospectively reviewed data from a multi-centre cohort of 128 patients having undergone revision THA between March 2017 and January 2019. An imageless computer navigation device (Intellijoint HIP®, Intellijoint Surgical, Kitchener, ON, Canada) was utilized in 69 surgeries and conventional methods were used in 59 surgeries. Acetabular component placement (anteversion, inclination) and the proportion of acetabular components placed in a functional safe zone (40° inclination/20° anteversion) were compared between navigation assisted and conventional THA groups. Results. Mean inclination decreased post-operatively versus baseline in both the navigation (44.9°±12.1° vs. 43.0°±6.8°, p=0.65) and control (45.8°±19.4° vs. 42.8°±7.1°, p=0.08) groups. Mean anteversion increased in both study groups, with a significant increase noted in the navigation group (18.6°±8.5° vs. 21.6°±7.8°, p=0.04) but not in the control group (19.4°±9.6° vs. 21.2°±9.8°, p=0.33). Post-operatively, a greater proportion of acetabular components were within ±10° of a functional target (40° inclination, 20° anteversion) in the navigation group (inclination: 59/67 (88%), anteversion: 56/67 (84%)) than in the control group (49/59 (83%) and 41/59, (69%), respectively). Acetabular component precision in both study groups improved post-operatively versus baseline. Variance in inclination improved significantly in both control (50.6° vs. 112.4°, p=0.002) and navigation (46.2° vs. 141.1°, p<0.001) groups. Anteversion variance worsened in the control group (96.3° vs. 87.6°, p=0.36) but the navigation group showed improvement (61.2° vs. 72.7°, p=0.25). Post-operative variance amongst cup orientations in the navigation group (IN: 46.2°; AV: 61.2°) indicated significantly better precision than that observed in the control group (IN: 50.6°, p=0.36; AV: 96.3°, p=0.04). Discussion. Re-revision is required in up to 25% of revision THA cases, of which 36% are caused by instability. This places a significant burden on the health care system and highlights the importance of accurate component placement. Our data indicate that the use of imageless navigation in revision THA – by minimizing the likelihood of outliers – may contribute to lower rates of re-revision by improving component orientation in revision THA. Conclusion. Utilizing imageless navigation in revision THAs results in more consistent placement of the acetabular component as compared to non-navigated revision surgeries

Background. Periprosthetic joint infection (PJI) after knee arthroplasty surgery remains a serious complication. Yet, there is no international consensus on the surgical treatment of PJI. The purpose was to assess the prosthesis survival rates, risk of re-revision, and mortality rate following the different surgical strategies (1-stage or 2-stage implant revision, and irrigation and debridement (IAD) with implant retention) used to treat PJI. Methods. The study was based on 653 total knee arthroplasties (TKAs) revised due to PJI in the period 1994 to 2016. Kaplan-Meier (KM) and multiple Cox regression analyses were performed to assess the survival rate of these revisions and the risk of re-revisions. We also studied the mortality rates at 90 days and 1 year after revision for PJI. Results. Of the 653 revision TKAs; 329, 81, and 243 revisions were performed with IAD, 1-stage, and 2-stage revision procedures, respectively. During the follow-up period, 19%, 12.3% and 11.5% of the IAD, 1-stage, and 2-stage revision cases were re-revised due to PJI, respectively. With any reasons of re-revision as end-point the 5 year KM survival of the index revision procedure was 76%, 82%, and 84% after IAD, 1-stage, and 2-stage revision, respectively. Similarly, the 5-year KM survival with a re-revision for infection as end-point was 79%, 88%, and 87% after IAD, 1-stage, and 2-stage revision, respectively. There were no statistically significant differences between 1-stage and 2-stage revision for re-revision of any reasons (RR=1.6; 95% CI: 0.8–3.1) nor did we find a difference for re-revision due to deep infection (RR=1.4; 95% CI: 0.6–3.1) as end-point. In an age-stratified analysis, however, the risk of re-revision for any causes was 4 times increased after 1-stage revision compared to 2-stage revision in patients over 70 years of age (RR=4.2, 95% CI: 1.3–13.7) but the risk was similar for deep infection as end-point. Age had no statistically significant effect on the risk of re-revision for knees revised with the IAD procedure. The 90-days and 1-year mortality rate after revision for PJI were 2.1% and 3.6% after IAD, 1.2% and 1.2% after 1-stage revision, and 0.4% and 1.6% after 2-stage revision and there were no statistically significant differences in mortality rate according to revision procedure. Conclusion. IAD had good results compared to earlier published studies. Despite that 1-stage revisions had a 4 times higher risk for re-revision compared to 2-stage revisions in older patients, the overall outcomes after 1-stage and 2-stage revision were similar

Aim. Dalbavancin is a novel second-generation lipoglycopeptide antibiotic with strong activity against many gram-positive bacteria and a prolonged half-life of 6–11 days. This allows a once-a-week intravenous application and therefore an outpatient intravenous therapy. Currently, only little is known about the use of Dalbavancin in Periprosthetic joint infection (PJI). The aim of this retrospective study, was to compare the outcome of hip and knee periprosthetic joint infections (PJI) in patients who received dalbavancin (DAL) with patients which was treated by standard of care antimicrobial agents (SoC). Methods. Between 02/2017 and 02/2020 a total of 89 (42 male/47 female) patients with PJI of the hip 56/89 (62.9%) and knee 33/89 (37.1%) who received at least one dosage of Dalbavancin were included. A 1:1 propensity-score (PS) matching between the DAL-group (n=89) and the SoC-group (n=89) was performed, using defined demographic covariates such as body-mass-index, age, sex, causative pathogens, knee or hip joint and infection after primary or revision surgery, surgical site infections, Charlson-comorbidity index and the types of infection (acute, late acute and chronic). Patient's demographics were analysed by our prospectively maintained institutional arthroplasty registry and PJI database. We analysed the outcome of the included patients evaluate the re-infection and re-revision rate and gave details about surgical management and the type of PJI with a minimum follow-up of one year. Results. Microbiological and clinical successes were achieved in 69 (77.5%) patients of the DAL-group and in 66 (74.2%) patients of the SoC-group. In the DAL-group 13 (14.6%) and in the SoC-group 12 (13.5%) patients had an infection related re-revision. Median follow-up was 706 (369; 1310) days in the DAL-group and 1329 (9; 3,549) days in the SoC-group. Overall, polymicrobial infections were found in 20 procedures (DAL-group: 10; SoC-group: 10) and monomicrobial infections in 154 (DAL-group: 75; SoC-group: 79). Polymicrobial infections were found in 20 patients and monomicrobial infections in 154. The most common microorganisms were Staphylococcus epidermidis n=63 (32.3%), Staphylococcus aureus n=27 (13.8%) and Cutibacterium spp. n=22 (11.3%). There are significantly less Gram-positive microorganisms (p=0.034) after re-revisions in patients with DAL treatment. Conclusions. Dalbavancin has excellent safety and high clinical effectiveness for Gram-positive PJIs

Introduction. Biological repair of acetabular bone defects after impaction bone grafting (IBG) in total hip arthroplasty could facilitate future re-revisions in case of failure of the reconstruction again using the same technique. Few studies have analysed the outcome of these acetabular re-revisions. Patients and Methods. We analysed 34 consecutive acetabular re-revisions that repeated IBG and a cemented cup in a cohort of 330 acetabular IBG revisions. Fresh-frozen femoral head allografts were morselized manually. All data were prospectively collected. Kaplan-Meier survivorship analysis was performed. The mean follow-up after re-revision was 7.2 years (2–17). Intraoperative bone defect had lessened after the first failed revision. At the first revision there were 14 hips with Paprosky 3A and 20 with Paprosky type 3B. At the re-revision there were 5 hips with Paproky 2B, 21 with Paprosky type 3A and 8 with type 3B. Lateral mesh was used in 19 hips. Results. The mean Harris Hip Score improved from 45.4 (6.7) to 77.1 (15.6) at final follow-up. The radiological analysis showed cup migration in 11 hips. The mean appearance time was 25 months (3–72). Of these, migration in three cups was progressive and painful requiring re-revision. Cup tilt was found in all migrated hips. There were one dislocation requiring a cemented dual mobility cup associated with IBG and one infection resolved with resection-arthroplasty. Survival with further cup revision for aseptic loosening was 80.7% (95% Confidence Interval 57.4–100) at 11 years. In all surviving re-revisions trabecular incorporation was observed without radiolucent lines. Conclusion. Biological repair can be obtained by restoring the bone stock, even after successive acetabular reconstructions using IBG and a cemented cup

Aim. The prevalence of unexpected positive cultures (UPC) in aseptic revision surgery of the joint with a prior septic revision procedure in the same joint remain unknown. The purpose of this study was to determine the prevalence of UPC in aseptic revisions performed in patients with a previous septic revision in the same joint. As secondary outcome measure, we explore possible risk factors associated with UPC and the re-revision rates. Method. This retrospective single-center study includes all patients between January 2016 and October 2018 with an aseptic revision total hip or knee arthroplasty procedure with a prior septic revision in the same joint. Patients with less than three microbiology samples, without joint aspiration or with aseptic revision surgery performed <3 weeks after a septic revision were excluded. UPC was defined as a single positive culture in a revision that the surgeon had classified as aseptic according to the 2018 International Consensus Meeting. Results. A total of 139 revision total hip/knee arthroplasties in patients with a previous septic revision were performed during the study period. After excluding 47 cases with insufficient information, a total of 92 patients were recruited for final analysis. The patient cohort consist of 52 males and 40 females with a mean age of 70 years (±10.6). There were 66 (71.7%) hips and 26 (28.3%) knees. The mean time between the septic and the aseptic revision was 83 months (±89). The two main causes for the aseptic revision were aseptic loosening (n=57, 62%) followed by instability (n=21, 22.9%). We identified 11 (12%) UPC in the entire cohort, while in 3 cases there was a concordance of the germ compared to the previous septic surgery. There were no differences for the presence of UPC between hips and knees (p=0.282), diabetes (p=0.701), immunosuppression (p= 0.252), previous one-stage or two-stages septic revision (p=0.316), or between the causes for the aseptic revision ((p=0.429). There was no correlation between the UPC and time after the septic revision (p=0.773). Conclusions. The prevalence of UPC in this specific group was similar to those reported in the literature for aseptic revisons. More studies, regarding this patient group are necessitated to better understand and more securely interprete the results in those high-risk aseptic revisions

Converting UKA to TKA can be difficult, and specialised techniques are needed. Issues include bone loss, joint line approximation, sizing, and rotation. Determining the complexity of conversion preoperatively helps predict the need for augmentation, grafting, stems, or constraint. In a 2009 study from our center, 50 UKA revised to TKA (1997–2007) were reviewed: 9 modular fixed-bearing, 4 metal-backed nonmodular fixed-bearing, 8 resurfacing onlay, 10 all-polyethylene step-cut, and 19 mobile bearing designs; 5 knees failed due to infection, 5 due to wear and/or instability, 10 for pain or progression of arthritis, 8 for tibial fracture or severe subsidence, and 22 due to loosening of either one or both components. Insert thickness was no different between implants or failure modes. Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Reestablishing the joint line, ligamentous balance, and durable fixation are critical to assuring a primary outcome. In a 2013 multicenter study of 3 institutions including ours, a total of 175 revisions of medial UKA in 168 patients (average age: 66 years) performed from 1995 to 2009 with a minimum 2-year clinical follow-up were reviewed. The average time from UKA to revision TKA was 71.5 months (2–262). The four most common reasons for failure were femoral or tibial loosening (55%), progressive arthritis of the lateral or patellofemoral joints (34%), polyethylene failure (4%) and infection (3%). Mean follow-up after revision was 75 months. Nine of 175 knees (4.5%) were subsequently revised at an average of 48 months (6–123). The average Knee Society pain and function score increased to 75 and 66, respectively. In the present series, the re-revision rate after revision TKA from UKA was 4.5% at an average of 75 months. In a current study from our center, 184 patients (193 UKA) underwent revision procedures (1996–2015) with minimum 2-year follow-up. Mean age was 63.5 (37–84) years, body mass index was 32.3 (19–57) kg/m. 2. , and interval after UKA was 4.8 (0–35) years. Most prevalent indications for revision were aseptic loosening (42%), arthritic progression (20%) and tibial collapse (14%). At 6.1 years mean follow-up (2–20), 8 knees (4.1%) have required re-revision involving any part, which is similar to what we recently reported at 5.5 years in a group of patients who underwent primary TKA (6 of 189; 3.2%), and much lower than what we observed at 6.0 years in a recent report of patients who underwent aseptic revision TKA (35 of 278; 12.6%). In the study group, Knee Society clinical and function scores improved from 50.8 and 52.1 preoperatively to 83.4 and 67.6 at most recent evaluation, respectively. Re-revisions were for aseptic loosening (3), instability (2), arthrofibrosis (2), and infection (1). Compared to published individual institution and national registry data, re-revision rates of failed UKA are equivalent to revision rates of primary TKA and substantially better than re-revision rates of revision TKA. These data should be used to counsel patients undergoing revision UKA to TKA

Introduction. The burden of prosthetic joint infection (PJI) in total knee arthroplasty (TKA) has been rising in line with the number of primary operations performed. Current estimates suggest an infection rate of 1–2.4%. Two-stage revision has traditionally been considered the gold standard of treatment; however, some studies suggest comparable results can be achieved with single-stage procedures. The potential advantages include less time in hospital, a single anaesthetic, reduced costs, and greater patient satisfaction. Methods. We reviewed data for 72 patients (47 males, 25 females), with a mean age of 71 years (range, 49 to 94), who underwent single-stage revision TKA for confirmed PJI between 2006 and 2016. A standardized debridement protocol was performed with immediate single-stage exchange. All cases were discussed preoperatively at multidisciplinary team (MDT) meetings, which included input from a senior musculoskeletal microbiologist. Patients were not excluded for previous revisions, culture-negative PJI, or the presence of a sinus. Results. The average length of follow-up was 8 years (range, 2 to 13). In total, 65 patients (90.3%) were infection free at most recent follow-up, with seven reinfections (9.7%). Three of these patients with recurrent infections underwent arthrodesis, two underwent re-revision, and two received long-term antibiotics following debridement and implant retention (DAIR). No amputations were undertaken. Conclusions. Single-stage revision for the infected TKA, according to a strict debridement protocol with MDT input, demonstrates reinfection rates comparable with two-stage revision procedures. This is the largest single-surgeon series to date, with extensive follow-up, and supports a growing evidence base for one-stage exchange