Source of the study: University of Auckland, Auckland, New Zealand and University of Otago, Christchurch, New Zealand. Outcomes following knee arthroplasty are typically defined as implant survivorship at defined timepoints, or revision incidence over time. These estimates are difficult to conceptualise, and lack context for younger patients with more remaining years of life. We therefore aimed to determine a ‘lifetime’ risk of revision as a more useful metric for total (TKA) and unicompartmental knee arthroplasty (UKA). The New Zealand Joint Registry was used to identify 96,497 primary TKAs and 13,481 primary UKAs performed between 1999 and 2019. Patient mortality and revision incidence were also extracted. Estimates of lifetime risk were calculated using an actuarial lifetable method. The estimates were stratified by age and gender. Reasons for revision were categorised using previously published standardised definitions. The lifetime risk of UKA revision was two-fold higher than TKA across all age groups (range 3.7-40.4% UKA, 1.6-22.4% TKA). Revision risk was higher for males with TKA (range 3.4%-25.2% males, 1.1%-20% females), but higher for females with UKA (range 4.3%-43.4% vs. 2.9%-37.4% for males). Revision due to infections were higher for TKA (1.5% males, 0.7% females) compared with UKA (0.4% males, 0.1% females). The increased risk in younger UKA patients was associated with higher incidence of aseptic loosening (UKA 2%, TKA 1%) and ‘unexplained pain’ (UKA 2%, TKA 0.2%). The risk for UKA was two-fold higher than TKA, and this was partially explained by a higher proportion of revisions due to ‘unexplained pain’. For TKA, males had higher risk of revision, in contrast to UKA where females had higher risk; this gender difference was associated with higher incidence of infections with TKA. Younger age, gender and higher ASA status were also associated with increased lifetime risk of UKA revision. Lifetime risk of revision can provide a meaningful measure of arthroplasty outcomes to aid patient counselling

Revision is a key negative outcome of joint replacements. The purpose of this abstract is to present revision risk curves for hip and knee replacements based on the most recently available national data sources. Having a better understanding of determinants of revision risk can help inform clinical and health care system improvements. We explored revision risk of primary joint replacement stratified by key clinical, prosthesis, and surgeon-level factors using data from three databases managed by CIHI: the Canadian Joint Replacement Registry (CJRR), the Discharge Abstract Database, and the National Ambulatory Care Reporting System. To investigate early revisions, we used Kaplan-Meier analysis stratified by demographic factors to determine the risk of revision within up to five years of primary surgery. This analysis identified the primary cohort from the CJRR from April 1, 2012 to March 31, 2017 and was limited to mandatory reporting provinces (British Columbia, Manitoba and Ontario) to ensure maximal coverage of prosthesis information. Bearing surface was obtained from the International Prosthesis Library maintained by the International Consortium of Orthopaedic Registries (ICOR) and the International Society of Arthroplasty Registers (ISAR). The total revision risk cohort contained 283,620 primary surgeries, of which 5,765 (2%) had at least one revision. For total hip arthroplasties, revision risk at the end of the follow-up period did not differ by age, by sex or across bearing surface (metal on cross-linked polyethylene [XLPE], ceramic on XLPE, ceramic on ceramic, metal on non-cross-linked polyethylene). For hemiarthroplasties in hip fracture patients, cement fixation was significantly associated with decreased revision risk. Surgeon volume had a positive effect on survivorship with cementless fixation (2.7% at one year [95% CI 2.3%, 3.1%] for high-volume vs 3.2% [2.7%, 3.7%] for low-volume). However, surgeon volume did not have an effect on survivorship with cemented fixation (2% at one year [95% CI 1.3%, 2.6%] for high-volume vs. 2% [1.4%, 2.6%] for low-volume). For total knee replacements, revision risk increased with decreasing age and male sex. For patients aged 75 and older, four-year revision risks were 1.5% (95% CI 1.3%, 1.7%) for women and 2.0% (1.7%, 2.3%) for men, but for patients under 55 years old, they were 4.3% (3.7%, 5%) for women and 5.9% (4.9%, 6.9%) for men. Additional results from the upcoming 2019 CJRR annual report, including data up to March 31, 2018, will be presented. Revisions represent a key failure of the primary replacement, they are costly to the health care system and negatively affect patients' quality of life. CJRR's coverage is currently 72%, increased coverage and follow-up time will allow increasingly comprehensive reporting on hip and knee prostheses in Canada. Future work in this area involves exploring additional prosthesis attributes for stratification of revision risk curves and calculation of hazards ratios adjusted by age and sex

OSSTEC is a pre-spin-out venture at Imperial College London seeking industry feedback on our orthopaedic implants which maintain bone quality in the long term. Existing orthopaedic implants provide successful treatment for knee osteoarthritis, however, they cause loss of bone quality over time, leading to more dangerous and expensive revision surgeries and high implant failure rates in young patients. OSSTEC tibial implants stimulate healthy bone growth allowing simple primary revision surgery which will provide value for all stakeholders. This could allow existing orthopaedics manufacturers to capture high growth in existing and emerging markets while offering hospitals and surgeons a safer revision treatment for patients and a 35% annual saving on lifetime costs. For patients, our implant technology could mean additional years of quality life by revising patients to a primary TKA before full revision surgery. Our implants use patent-filed additive manufacturing technology to restore a healthy mechanical environment in the proximal tibia; stimulating long term bone growth. Proven benefits of this technology include increased bone formation and osseointegration, shown in an animal model, and restoration of native load transfer, shown in a human cadaveric model. This technology could help capture the large annual growth (24%) currently seen in the cementless knee reconstruction market, worth $1.2B. Furthermore, analysis suggests an additional market of currently untreated younger patients exists, worth £0.8B and growing by 18% annually. Making revision surgery and therefore treatment of younger patients easier would enable access to this market. We aim to offer improved patient treatment via B2B sales of implants to existing orthopaedic manufacturer partners, who would then provide them with instrumentation to hospitals and surgeons. Existing implant materials provide good options for patient treatments, however OSSTEC's porous titanium structures offer unique competitive advantages; combining options for modular design, cementless fixation, initial bone fixation and crucially long term bone maintenance. Speaking to surgeons across global markets shows that many surgeons are keen to pursue bone preserving surgeries and the use of porous implants. Furthermore, there is a growing demand to treat young patients (with 25% growth in patients younger than 65 over the past 10 years) and to use cementless knee treatments, where patient volume has doubled in the past 4 years and is following trends in hip treatments. Our team includes engineers and consultant surgeons who have experience developing multiple orthopaedic implants which have treated over 200,000 patients. To date we have raised £175,000 for the research and development of these implants and we hope to gain insight from industry professionals before further development towards our aim to begin trials for regulatory approval in 2026. OSSTEC implants provide a way to stimulate bone growth after surgery to reduce revision risk. We hope this could allow orthopaedic manufactures to explore high growth markets while meaning surgeons can treat younger patients in a cost effective way and add quality years to patients' lives

Modular total hip arthroplasty (MTHA) stems were introduced in order to provide increased intra-operative flexibility for restoring hip biomechanics, improving stability and potentially reducing revision risk. However, the additional interface at the neck-body junction provides another location for corrosion or mechanical failure of the stem. To delineate the mid term revision risk of MTHA stems, we examined data from the Canadian Joint Replacement Registry (CJRR) at the Canadian Institute for Health Information (CIHI). Kinectiv, Profemur and Rejuvenate modular stems were identified from CJRR records submitted between 2004 and 2014. Revision status was determined by examining the discharge abstract database (DAD) also housed by CIHI, which collects information on all revisions, regardless of whether the procedure was submitted to CJRR. A total of 2446 modular stems were identified with a mean follow up of 4.2 years (range 0 to 10). Their usage peaked in 2012 (the first year of mandatory CJRR form submission for BC, ON and MB), and dropped rapidly thereafter. A total of 155 (6.3%) were revised. This consisted of 5/301 Kinectiv (1.7%), 141/2050 ProFemur (6.9%), and 9/96 Rejuvenate (9.4%) stems. As a group, this falls below the National Institute for Clinical Excellence (NICE) guidelines of 95% survival at 10 years. While MTHA stems were introduced to improve outcomes and reduce revision risk, our findings of a 6.3% revision risk at a mean follow up of 4.2 years does not appear to support this

The objective of this study was to determine whether the bearing surface is a risk factor for revision after late dislocation in total hip arthroplasty (THA). Data from primary THAs were extracted from the New Zealand Joint Registry over a 13-year period. The mean age of patients was 68.9 years; 53.2% were female. The surgical approach used was posterior in 66% of THAs, lateral in 29% and anterior in 5%. There were 53,331 (65.1%) metal-on-polyethylene THAs, 14,093 (17.2%) ceramic-on-polyethylene, 8,177 (10.0%) ceramic-on-ceramic, 461 (0.5%) ceramic-on-metal, 5910, and (7.2%) metal-on-metal. The primary endpoint was late revision for dislocation, with ‘late’ defined as greater than one year post-operatively. 73,386 hips were available for analysis. The overall revision rate was 4.3% (3,130 THAs), 1.1% (836) were revised for dislocation. Only 0.65% (470) hips were revised for dislocation after the first post-operative year. The unadjusted hazard ratios (HR) showed significantly higher rates of revision for dislocation in ceramic-on-polyethylene (HR 2.48; p=0.001) and metal-on-polyethylene (HR 2.00; 95% p =0.007) compared to ceramic-on-ceramic. However, when adjusted for head size, age and surgical approach, only ceramic-on-polyethylene (HR 2.10; p=0.021) maintained a significantly higher rate of revision, whereas metal-on-polyethylene approached significance (HR 1.76; 95% p = 0.075). In New Zealand, dislocation is the most common reason for revision, ahead of aseptic loosening of the acetabular component. The relationships between bearing materials and risk of revision for late dislocation is controversial. However, in this study ceramic-on-ceramic shows lower risk rates for revision than other bearing surface combinations. Low wear and less debris, limited peri-articular inflammatory reaction and an healthy fibrotic pseudo-capsule are potential factors determining long-term stability of the hip joint

We compared the rate of revision of two classes of primary anatomic shoulder arthroplasty, stemmed (aTSA) and stemless (sTSA) undertaken with cemented all polyethylene glenoid components. A large national arthroplasty registry identified two cohort groups for comparison, aTSA and sTSA between 1. st. January 2011 and 31. st. December 2020. A sub-analysis from 1 January 2017 captured additional patient demographics. The cumulative percentage revision (CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazard models adjusted for age and gender. Of the 7,533 aTSA procedures, the CPR at 8 years was 5.3% and for 2,567 sTSA procedures was 4.0%. There was no difference in the risk of revision between study groups (p=0.128). There was an increased risk of revision for aTSA and sTSA undertaken with humeral head sizes <44mm (p=0.006 and p=0.002 respectively). Low mean surgeon volume (MSV) (<10 cases per annum) was a revision risk for aTSA (p=0.033) but not sTSA (p=0.926). For primary diagnosis osteoarthritis since 2017, low MSV was associated with an increased revision risk for aTSA vs sTSA in the first year (p=0.048). Conversely, low MSV was associated with a decreased revision risk for sTSA in the first 6 months (p<0.001). Predominantly aTSA was revised for loosening (28.8%) and sTSA for instability/dislocation (40.6%). Revision risk of aTSA and sTSA was associated with humeral head size and mean surgeon volume but not patient characteristics. Inexperienced shoulder arthroplasty surgeons experience lower early revision rates with sTSA in the setting of osteoarthritis. Revision of aTSA and sTSA occurred for differing reasons

Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian Registry Study where 68447 patients were identified for having a hip hemiarthroplasty from 2012-2020. This is a retrospective cohort study, identifying patients that had cementless or cemented hip hemiarthroplasty. The surgeons who performed the procedures were linked to the procedure Total Hip Replacement. Individuals were categorized as experienced hip surgeons or not based on whether they performed 50 hip replacements a year. Identifying high volume surgeon (>50 cases/year) and low volume (<50 cases/year) surgeons. Hazard ratios adjusted for age and sex were performed for risk of revision over this 8-year span. A p-value <0.05 was deemed significant. For high volume surgeons, cementless fixation had a higher revision risk than cemented fixation, HR 1.29 (1.05-1.56), p=0.017. This pattern was similar for low volume surgeons, with cementless fixation having a higher revision risk than cemented fixation, HR 1.37 (1.11-1.70) p=0.004 We could not detect a difference in revision risk for cemented fixation between low volume and high volume surgeons; at 0-1.5 years the HR was 0.96 (0.72-1.28) p=0.786, and at 1.5+ years the HR was 1.61 (0.83-3.11) p=0.159. Similarly, we could not detect a difference in revision risk for cementless fixation between low volume and high volume surgeons, HR 1.11 (0.96-1.29) p=0.161. Using large registry data, cemented hip hemiarthroplasty has a significant lower revision rate than the use of cementless stems even when surgeons are stratified to high and low volume. Low volume surgeons who use uncemented prostheses have the highest rate of revision. The low volume hip surgeon who cements has a lower revision rate than the high volume cementless surgeon. The results of this study should help to guide surgeons that no matter the level of experience, using a cemented hip hemiarthroplasty for acute femoral neck fracture is the safest option. That high volume surgeons who perform cementless hemiarthroplasty are not immune to having revisions due to their technique. Increased training and education should be offered to surgeons to improve comfort when using this technique

Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian Registry Study where 68447 patients were identified for having a hip hemiarthroplasty from 2012-2020. This is a retrospective cohort study, identifying patients that had cementless or cemented hip hemiarthroplasty. The surgeons who performed the procedures were linked to the procedure Total Hip Replacement. Individuals were categorized as experienced hip surgeons or not based on whether they performed 50 hip replacements a year. Identifying high volume surgeon (>50 cases/year) and low volume (<50 cases/year) surgeons. Hazard ratios adjusted for age and sex were performed for risk of revision over this 8-year span. A p-value <0.05 was deemed significant. For high volume surgeons, cementless fixation had a higher revision risk than cemented fixation, HR 1.29 (1.05-1.56), p=0.017. This pattern was similar for low volume surgeons, with cementless fixation having a higher revision risk than cemented fixation, HR 1.37 (1.11-1.70) p=0.004 We could not detect a difference in revision risk for cemented fixation between low volume and high volume surgeons; at 0-1.5 years the HR was 0.96 (0.72-1.28) p=0.786, and at 1.5+ years the HR was 1.61 (0.83-3.11) p=0.159. Similarly, we could not detect a difference in revision risk for cementless fixation between low volume and high volume surgeons, HR 1.11 (0.96-1.29) p=0.161. Using large registry data, cemented hip hemiarthroplasty has a significant lower revision rate than the use of cementless stems even when surgeons are stratified to high and low volume. Low volume surgeons who use uncemented prostheses have the highest rate of revision. The low volume hip surgeon who cements has a lower revision rate than the high volume cementless surgeon. The results of this study should help to guide surgeons that no matter the level of experience, using a cemented hip hemiarthroplasty for acute femoral neck fracture is the safest option. That high volume surgeons who perform cementless hemiarthroplasty are not immune to having revisions due to their technique. Increased training and education should be offered to surgeons to improve comfort when using this technique

Increasing femoral offset in total hip replacement (THR) has several benefits including improved hip abductor strength and enhanced range of motion. Biomechanical studies have suggested that this may negatively impact on stem stability. However, it is unclear whether this has a clinical impact. Using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), the aim of this study was to determine the impact of stem offset and stem size for the three most common cementless THR prostheses revised for aseptic loosening. The study period was September 1999 to December 2020. The study population included all primary procedures for osteoarthritis with a cementless THR using the Corail, Quadra-H and Polarstem. Procedures were divided into small and large stem sizes and by standard and high stem offset for each stem system. Hazard ratios (HR) from Cox proportional hazards models, adjusting for age and gender, were performed to compare revision for aseptic loosening for offset and stem size for each of the three femoral stems. There were 55,194 Corail stems, 13,642 Quadra-H stem, and 13,736 Polarstem prostheses included in this study. For the Corail stem, offset had an impact only when small stems were used (sizes 8-11). Revision for aseptic loosening was increased for the high offset stem (HR=1.90;95% CI 1.53–2.37;p<0.001). There was also a higher revision risk for aseptic loosening for high offset small size Quadra-H stems (sizes 0-3). Similar to the Corail stem, offset did not impact on the revision risk for larger stems (Corail sizes 12-20, Quadra-H sizes 4-7). The Polarstem did not show any difference in aseptic loosening revision risk when high and standard offset stems were compared, and this was irrespective of stem size. High offset may be associated with increased revision for aseptic loosening, but this is both stem size and prosthesis specific

External validation of machine learning predictive models is achieved through evaluation of model performance on different groups of patients than were used for algorithm development. This important step is uncommonly performed, inhibiting clinical translation of newly developed models. Recently, machine learning was used to develop a tool that can quantify revision risk for a patient undergoing primary anterior cruciate ligament (ACL) reconstruction (https://swastvedt.shinyapps.io/calculator_rev/). The source of data included nearly 25,000 patients with primary ACL reconstruction recorded in the Norwegian Knee Ligament Register (NKLR). The result was a well-calibrated tool capable of predicting revision risk one, two, and five years after primary ACL reconstruction with moderate accuracy. The purpose of this study was to determine the external validity of the NKLR model by assessing algorithm performance when applied to patients from the Danish Knee Ligament Registry (DKLR). The primary outcome measure of the NKLR model was probability of revision ACL reconstruction within 1, 2, and/or 5 years. For the index study, 24 total predictor variables in the NKLR were included and the models eliminated variables which did not significantly improve prediction ability - without sacrificing accuracy. The result was a well calibrated algorithm developed using the Cox Lasso model that only required five variables (out of the original 24) for outcome prediction. For this external validation study, all DKLR patients with complete data for the five variables required for NKLR prediction were included. The five variables were: graft choice, femur fixation device, Knee Injury and Osteoarthritis Outcome Score (KOOS) Quality of Life subscale score at surgery, years from injury to surgery, and age at surgery. Predicted revision probabilities were calculated for all DKLR patients. The model performance was assessed using the same metrics as the NKLR study: concordance and calibration. In total, 10,922 DKLR patients were included for analysis. Average follow-up time or time-to-revision was 8.4 (±4.3) years and overall revision rate was 6.9%. Surgical technique trends (i.e., graft choice and fixation devices) and injury characteristics (i.e., concomitant meniscus and cartilage pathology) were dissimilar between registries. The model produced similar concordance when applied to the DKLR population compared to the original NKLR test data (DKLR: 0.68; NKLR: 0.68-0.69). Calibration was poorer for the DKLR population at one and five years post primary surgery but similar to the NKLR at two years. The NKLR machine learning algorithm demonstrated similar performance when applied to patients from the DKLR, suggesting that it is valid for application outside of the initial patient population. This represents the first machine learning model for predicting revision ACL reconstruction that has been externally validated. Clinicians can use this in-clinic calculator to estimate revision risk at a patient specific level when discussing outcome expectations pre-operatively. While encouraging, it should be noted that the performance of the model on patients undergoing ACL reconstruction outside of Scandinavia remains unknown

Source of the study: University of Auckland, Auckland, New Zealand and University of Otago, Christchurch, New Zealand. The Oxford Knee Score (OKS) is a 12-item questionnaire used to track knee arthroplasty outcomes. Validation of such patient reported outcome measures is typically anchored to a single question based on patient ‘satisfaction’, however risk of subsequent revision surgery is also an important outcome measure. The OKS can predict subsequent revision risk within two years, however it is not known which item(s) are the strongest predictors. Our aim was to identify which questions were most relevant in the prediction of subsequent knee arthroplasty revision risk. . All primary TKAs (n=27,708) and UKAs (n=8,415) captured by the New Zealand Joint Registry between 1999 and 2019 with at least one OKS response at six months, five years or ten years post-surgery were included. Logistic regression and receiver operating characteristics (ROC) curves were used to assess prediction models at six months, five years and ten years. Q1 ‘overall pain’ was the strongest predictor of revision within two years (TKA: 6 months, odds ratio (OR) 1.37; 5 years, OR 1.80; 10 years, OR 1.43; UKA: 6 months, OR 1.32; 5 years, OR 2.88; 10 years, OR 1.85; all p<0.05). A reduced model with just three questions (Q1, Q6 ‘limping when walking’, Q10 ‘knee giving way’) showed comparable or better diagnostic ability with the full OKS (area under the curve (AUC): TKA: 6 months, 0.77 vs. 0.76; 5 years, 0.78 vs. 0.75; 10 years, 0.76 vs. 0.73; UKA: 6 months, 0.80 vs. 0.78; 5 years: 0.81 vs. 0.77; 10 years, 0.80 vs. 0.77). The three questions on overall knee pain, limping when walking, and knee ‘giving way’ were the strongest predictors of subsequent revision within two years. Attention to the responses for these three key questions during follow-up may allow for prompt identification of patients most at risk of revision

Strategy regarding patella resurfacing in total knee replacement (TKR) remains controversial. TKR revision rates are reportedly influenced by surgeon procedure volume. The study aim was to compare revision outcomes of TKR with and without patella resurfacing in different surgeon volume groups using data from the AOANJRR. The study population included 571,149 primary TKRs for osteoarthritis. Surgeons were classified as low, medium, or high-volume based on the quartiles of mean primary TKR volume between 2011 and 2020. Cumulative percent revision (CPR) using Kaplan-Meier estimates of survivorship were calculated for the three surgeon volume groups with and without patella resurfacing. Cox proportional hazards models, adjusted for age and sex, were used to compare revision risks. High-volume surgeons who did not resurface the patella had the highest all-cause CPR (20-year CPR 10.9%, 95% CI [10.0%, 12.0%]). When the patella was resurfaced, high-volume surgeons had the lowest revision rate (7.3%, 95% CI [6.4%, 8.4%]). When the high-volume groups were compared there was a higher rate of revision for the non-resurfaced group after 6 months. When the medium-volume surgeon groups were compared, not resurfacing the patella also was associated with a higher rate of revision after 3 months. The low-volume comparisons showed an initial higher rate of revision with patella resurfacing, but there was no difference after 3 months. When only patella revisions were considered, there were higher rates of revision in all three volume groups where the patella was not resurfaced. TKR performed by high and medium-volume surgeons without patella resurfacing had higher revision rates compared to when the patella was resurfaced. Resurfacing the patella in the primary procedure protected against revision for patella reasons in all surgeon volume groups. Level of evidence: III (National registry analysis)

Source of the study: University of Auckland, Auckland, New Zealand. Unicompartmental knee arthroplasty (UKA) is effective for patients with isolated compartment osteoarthritis, however the procedure has higher revision rates. Long-term survivorship and accurate characterisation of revision reasons are limited by a lack of long-term data and standardised revision definitions. We aimed to identify survivorship, risk factors and revision reasons in a large UKA cohort with up to 20 years follow-up. Patient, implant and revision details were recorded through clinical and radiological review for 2,137 consecutive patients undergoing primary medial UKA across Auckland, Canterbury, Counties Manukau and Waitematā DHB between 2000 and 2017. Revision reasons were determined from review of clinical, laboratory, and radiological records for each patient using a standardised protocol. To ensure complete follow-up data was cross-referenced with the New Zealand Joint Registry to identify patients undergoing subsequent revision outside the hospitals. Implant survival, revision risk and revision reasons were analysed using Cox proportional-hazards and competing risk analyses. Implant survivorship at 15 years was comparable for cemented fixed-bearing (cemFB; 91%) and uncemented mobile-bearing (uncemMB; 91%), but lower for cemented mobile-bearing (cemMB; 80%) implants. There was higher incidence of aseptic loosening with cemented implants (3–4% vs. 0.4% uncemented, p<0.01), osteoarthritis (OA) progression with cemMB implants (9% vs. 3% cemFB/uncemMB; p<0.05) and bearing dislocations with uncemMB implants (3% vs. 2% cemMB, p=0.02). Compared with the oldest patients (≥75 years), there was a nearly two-fold increase in risk for those aged 55–64 (hazard ratio 1.9; confidence interval 1.1-3.3, p=0.03). No association was found with gender, BMI or ASA. Cemented mobile-bearing implants and younger age were linked to lower implant survivorship. These were associated with disease progression and bearing dislocations. The use of cemented fixed-bearing and uncemented mobile-bearing designs have superior comparable long-term survivorship

Introduction/Aim. Outcomes for guided motion primary total knee arthroplasty (TKA) in obese patients are unknown. Materials and Methods. 1,684 consecutive patients underwent 2,059 primary TKAs with a second-generation guided motion implant (Journey II Bi-Cruciate Stabilized Knee System, Smith & Nephew, Inc., Memphis) between 2011–2017 at three European and seven US sites. Results. Of 2,003 (97.3%) TKAs in 1,644 patients with BMI data: average age 64.5 years; 58.4% females; average BMI 32.5 kg/m. 2. ;13.4% had BMI ≥ 40 kg/m. 2. Subjects with BMI ≥ 40 kg/m. 2. had longest length of hospital stay (LOS) at European sites; LOS similar at US sites. Subjects with BMI ≥ 40 kg/m. 2. (P=0.0349) had longest surgery duration. BMI ≥ 40 kg/m. 2. had more re-hospitalizations or post-TKA reoperations than BMI < 40 kg/m. 2. (12.7% and 9.2% at five-year post-TKA, P<.0495). 62 TKAs were revised (3.39/100 TKA at five years) with no differences in revision risk between groups. 17 (27.4%) revisions involved femoral or tibial component removal; 45 (72.6%) involved tibial insert or patellar component removal only with revision risk similar between groups. Discussion. Our results corroborate literature-reported revision outcomes of standard TKAs in obese patients. Conclusion. Surgery duration and long-term complication rates are higher in patients with BMI ≥ 40 kg/m. 2. , but device revision risk is not elevated

Aim. To describe the impact of a failed DAIR in the further prognosis of the prosthesis after a PJI. Method. A retrospective multicentrically study was conducted, including 10 institutions from all over the country. PJI-confirmed patients who underwent DAIR clinical records were revised. Age, sex, relevant previous conditions, Charlson comorbidity score, previous surgery, PJI diagnosis and surgical and antibiotic treatment, from the index surgery onwards. DAIR failure was defined as the removal of the prosthesis and/or an antibiotic suppressive treatment. Results. 95 failed DAIR were identified, 43 of whom were treated with another DAIR (70% success rate), 20 with one-stage revision (75% success rate) and 25 with two-stage revision (92% success rate). As risk factors for the failure of a second DAIR, a non-specialized surgical team(p=.0034), mobile components exchange(p=.009) and polymicrobial infections(p=.03) were identified. Regarding to one-stage revisions, no risk factors were identified, and regarding to two-stage revisions, polymicrobial infection were identified (p=.028). Conclusions. A second DAIR could sabe up to 70% of the prosthesis in our series. Furthermore, the outcome of the subsequent one or two-stage revision does not seem to be affected bay the previous failed DAIR. In terms of risk factors of failure, non-specialized surgical team, no mobile components exchange, and polymicrobial infections were identified for the DAIR, and polymicrobial infections for the two-stage revisions

Robotic and navigated TKA procedures have been introduced to improve component placement precision for the purpose of improving implant survivorship and other clinical outcomes. Although numerous studies have shown enhanced precision in placing components, adoption of technology-assistance (TA) for TKA has been relatively slow. One reason for this has been the difficulty in demonstrating the cost-effectiveness of implementing TA-TKA systems and assessing their impact on revision rates. In this study, we aimed to use a simulation approach to answer the following questions: (1) Can we determine the distribution of likely reductions in TKA revision rates attributable to TA-TKA in an average US patient population? And, (2) What reduction in TKA revision rates are required to achieve economic neutrality?. In a previous study, we developed a method for creating large sets of simulated TKA patient populations with distributions of patient-specific factors (age at index surgery, sex, BMI) and one surgeon-controlled factor (coronal alignment) drawn from registry data and published literature. Effect sizes of each factor on implant survival was modeled using large clinical studies. For 10,000 simulated TKA patients, we simulated 20,000 TKA surgeries, evenly split between groups representing coronal alignment precisions reported for manual (±3°) and TA-TKA (±1.0°), calculating the patient-specific survival curve for each group. Extending our previous study, we incorporated the probability of each patient's expected survival into our model using publicly available actuarial data. This allowed us to calculate a patient-specific estimate of the Reduction in Lifetime Risk of Revision (RLRR) for each simulated patient. Our analysis showed that 90% of patients will achieve an RLRRof 1.5% or less in an average US TKA population. We then conducted a simplified economic analysis with the goal of determining the net cost of using TA-TKA per case when factoring in future savings by TKA revision rates. We assumed an average cost of revision surgery to be $75,000 as reported by Delanois (2017) and an average added cost incurred by TA-TKA to be $6,000 per case as reported by Antonis (2019). We estimate the net cost per TA-TKA case (CNet) to be the added cost per TA-TKA intervention (CInt), less the cost of revision surgery (CRev) multiplied by the estimated RLRR: CNet = CInt - CRev∗RLRR. We find that, under these assumptions, use of TA-TKA increases expected costs for all patients with an RLRR of under 8%. Based on these results, it appears that it would not be cost-effective to use TA-TKA on more than a small fraction of the typical US TKA patient population if the goal is to reduce overall costs through reducing revision risks. However, we note that this simulation does not consider other possible reported benefits of TA-TKA surgery, such as improved functional and pain outcome scores which may justify its use on other grounds. Alternative costs incurred by TA-TKA will be evaluated in a future study. To reach economic neutrality, TA-TKA systems either must reduce the added cost per intervention or increase RLRR by better addressing the root causes of revision

Introduction. Following in-depth analysis of the market leading brand combinations in which we identified implant influences on risk of revision, we compared revision in patients implanted with different categories of hip replacement in order to find implant with the lowest revision risk, once known flawed options were removed. Methods. All patients with osteoarthritis who underwent a hip replacement (2003–2010) using an Exeter-Contemporary (cemented), Corail-Pinnacle (cementless), Exeter-Trident (Hybrid) or a Birmingham Hip resurfacing (BHR) were initially included within the analysis. Operations involving factors that were significant predictors of revision were excluded. Cox proportional hazard models were then used to assess the relative risk of revision for a category of implant (compared with cemented), after adjustment for patient covariates. Results. In males, overall 5-year revision was 1.4%. Implant category did not significantly influence revision risk (p=0.615) in < 60 after adjustment. In the 60–75 year group, resurfacing implants were a significant influence for revision (Hazard ratio (HR)=2.63, p< 0.001), and with a trend in cementless (HR=1.63, p=0.057). In males >75 years, cementless implants significantly influenced revision risk (HR=3.48, p=0.002). In females, overall 5-year revision was 1.0%. After adjustment, in < 60 group implant category did not significantly influence revision (p=0.199), although there was a trend towards higher revision in resurfacing implants (HR=3.53, p=0.065). In over 60 year olds, cementless implants were a significant influence for revision risk (60–75 years: HR=1.80, p=0.010, >75 years: HR=2.26, p=0.010. In the older group, there was also a trend towards higher revision with hybrid implants (HR=3.25, p=0.053). Discussion. In summary, after implant optimisation of the market leaders and patient risk adjustment we found that cementless implants had a higher revision compared with cemented in males over 75 and females over 60 years old. In males under 60 years, there were no significant differences in revision risk between implant types

Objectives. Total hip replacement is increasingly being conducted in younger and more active patients, so surgeons often use bearing surfaces with improved wear characteristics, such as ceramic on ceramic. The primary objective of this study was to determine if survivorship for a BIOLOX® delta ceramic on delta ceramic couple used with the PROCOTYL® L acetabular cup is significantly different from all other cementless cups in a large arthroplasty registry. The secondary objective of this study was to analyze patient reported outcomes measures (PROMs) of the subject cup with a minimum five year follow-up. Methods. Patient demographics and survivorship data was collected from the National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man (NJR) database for all total hip replacements performed with the PROCOTYL® L cup used in combination with a delta-on-delta articulation, as well as for all other cementless cups. Survivorship data was compared for all revisions and cup revisions only and data was adjusted to exclude metal on metal articulations. The hazard ratio of the subject system to all cementless cups was also calculated with the Cox Proportional Hazards model. Patients with the subject components implanted for a minimum of five years completed Oxford Hip, EQ-5D, and EQ VAS score questionnaires. Results. The patient demographic data collected for the subject components and all cementless cups is provided in Figure 1. Six-year survivorship for the subject cup (98.6%) was similar to survivorship for all cementless cup revisions in the NJR database (98.5%), as seen in Figure 2. When the cup alone was revised, six-year survivorship of the subject cup (98.6%) and all NJR cementless cups (98.5%) was also similar. However, the subject cup survivorship remained at 98.6% from 4 to 6 years post-implantation, while survivorship for all cementless cups decreased slightly from years 4 to 6. The similarities between the revision risk of the subject system and all cementless cups in the NJR can be seen in the Cox Proportional Hazards model for revision risk ratios provided in Figure 3. Patients with the subject cup implanted for an average of 5.88 years reported Oxford Hip, EQ-5D, and EQ VAS scores of 39.60 ± 10.78, 0.801 ± 0.259, and 75.49 ± 19.25, respectively. Conclusions. The subject acetabular cup with a ceramic on ceramic articulation exhibited similar survivorship to all other cementless acetabular cups, excluding those with metal on metal bearings, in the NJR. Patients implanted with the subject system for an average of 5.88 years reported what are considered satisfactory Oxford Hip, EQ-5D, and EQ VAS scores. This survivorship and PROMs data is the first report of mid-term outcomes with the subject components

Background. Substance abuse and dependence is thought to have a strongly negative impact on surgical outcomes. The purpose of this study was to determine the effects of drug misuse on total knee arthroplasty (TKA) revision incidence, revision causes, and time to revision by analyzing the Medicare database between 2005–2012. Methods. A retrospective review of the Medicare database within the PearlDiver Supercomputer (Warsaw, IN) for TKA and revisions was performed utilizing Current Procedural Terminology (CPT) and International Classification of Disease (ICD) ninth revision codes. Drug misuse was subdivided into cocaine, cannabis, opioids, sedative/hypnotic/anxiolytic, amphetamines, and alcohol. Time to revision, age, and gender were also investigated. Results. Our query returned 2159221 TKAs and 193024 (8.9%) revisions between 2005–2012. Drug misuse was prevalent in 173513 (8%). Cocaine had the highest revision incidence (13.9%). Cannabis had the fastest average (636.1 days) and median (457 days) time to revision. At 30 and 90 days, cannabis had the greatest rate of revision at 6% and 12% respectively. At 6 months and 1 year, amphetamine had the greatest revision risk at 25% and 40.5% respectively. Infection was the most common cause of revision among all substances. Conclusion. Cocaine misuse holds the highest risk for revision. However cannabis misuse is more likely to require revision sooner, particularly at the 30 and 90 day intervals. Infection was the most common cause of revision regardless of substance misused. Thus it is important to obtain a detailed social history on drug misuse and to be vigilant for postoperative infections in these patients

Introduction. Previous registry studies of ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) have focused on revision outcomes following primary surgery. Less is known about the effect of ceramic bearings on infection, dislocation, and mortality as outcomes following primary total hip arthroplasty (THA) for the Medicare population. We asked (1) does the use of C-PE bearings influence outcomes following THA as compared with metal-on-polyethylene (M-PE); and (2) does the use of COC bearings influence outcomes following THA as compared with M-PE?. Methods. A total of 315,784 elderly Medicare patients (65+) who underwent primary THA between 2005 and 2014 with known bearing types were identified from the Medicare 100% inpatient sample administrative database. Outcomes of interest included relative risk of 90-day readmission, infection, dislocation, revision, or mortality at any time point after primary surgery. Propensity scores were developed to adjust for selection bias in the choice of bearing type at index primary surgery. Cox regression incorporating propensity score stratification (10 levels) was then used to evaluate the impact of bearing surface selection on outcomes, after adjusting for patient-, hospital-, and surgeon-related factors. Results. For primary THA patients treated with C-PE bearings and COC bearings, there was significantly reduced risk of infection relative to M-PE bearings (C-PE Hazard Ratio, HR: 0.86, p=0.001; COC Hazard Ratio, HR: 0.74, p=0.01). For the C-PE cohort, we also observed reduced risk of 90-day readmission (HR: 0.94, p<0.001); dislocation (HR: 0.81, p<0.001); and mortality (HR: 0.92, p<0.001). There was no significant difference in risk of revision for either the C-PE or COC bearing cohorts when compared with M-PE. For the COC cohort, there was no significant difference in readmission, dislocation, or mortality risk. Conclusions. The results indicate that, after adjusting for selection bias and various confounding patient-, surgeon-, and hospital-related factors, Medicare patients treated with primary THA with ceramic bearings exhibit lower risk of infection than those treated with M-PE bearings. In addition, C-PE bearings were associated with lower risk of dislocation and mortality. As in previous registry studies, we found that ceramic bearings have similar revision risk as M-PE bearings in primary THA at between 8 and 9 years of follow-up. The findings of this study support further research into the long-term association between ceramic bearings in primary THA and clinical outcomes