Aims

The aim of this study is to report the implant survival and factors associated with revision of total elbow arthroplasty (TEA) using data from the Dutch national registry.

The importance of registries has been brought into focus by recent UK national reports focusing on implant (Cumberlege) and surgeon (Paterson) performance. National arthroplasty registries provide real-time, real-world information about implant, hospital, and surgeon performance and allow case identification in the event of product recall or adverse surgical outcomes. They are a valuable resource for research and service improvement given the volume of data recorded and the longitunidal nature of data collection. This review discusses the current value of registry data as it relates to both clinical practice and research. Cite this article: Bone Joint J 2023;105-B(4):356–360

Aim. In recent years, many studies on revision for infection after arthroplasty have been published. In national arthroplasty registers, revision for infection is defined as surgical debridement, with or without removal or exchange of the entire or parts of the prosthesis due to deep infection, and should be reported to the register immediately after surgery. The diagnosis of infection is made at the surgeon's discretion, based on pre- and perioperative assessment and evaluation, and is not to be corrected to the register based on peroperative bacterial cultures. Due to this lack of validation, the rate of revision for infection will only be an approximation of the true rate of periprosthetic joint infection (PJI). Our aim was to validate the reporting of infection after total hip arthroplasty, and to assess if revisions for infection actually represented true PJI. Methods. We investigated the reported revisions for infection and aseptic loosening after total hip arthroplasty from 12 hospitals, representing one region of the country, reported during the period 2010–2020. The electronic patient charts were investigated for information on surgical treatment, use of antibiotics, biochemistry and microbiology findings. PJI was defined as growth of at least two phenotypically identical microbes in perioperative tissue samples. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated. Results. 145 revisions for infection and 137 revisions for aseptic loosening were reported. Of the reported infections, there were 141/145 true positives and 4/145 false positives. Of the reported aseptic loosenings, there were 126/137 true negatives and 11/137 false negatives. This gives a positive predictive value of 0.97, negative predictive value of 0.92, sensitivity of 0.93, specificity of 0.97 and accuracy of 0.95. Interpretation. We found the reporting revision for infection after total hip arthroplasty to the national register accurate. There was high correlation between reported revision for infection and PJI. Studies on revision for infection from arthroplasty registers may therefore be considered as reliable as studies of true PJI

Introduction. This analysis aims to provide an update of the Level-IV Partners Arthroplasty Registry (PAR), a quality-improvement initiative and research data repository. Methods. The Harris Joint Registry was founded in 1969 and has since expanded to become the Partners Arthroplasty Registry (PAR). Today, the PAR captures data on total hip and total knee arthroplasties conducted at seven hospitals in Massachusetts. Over time, data has been sourced through independent collection at a single hospital, retrospective sourcing through the Research Patient Data Registry (RPDR), and currently through the Enterprise Data Warehouse (EDW). Various statistical methods analyzed changing trends of care provided to patients across affiliated institutions. PROMs collected in the PAR are the PROMIS Physical Function and Global Health Short Forms, the HOOS and KOOS. The registry is an associate member of ISAR and will incorporate the international implant library. Results. The PAR contains demographic, implant-specifics, and radiographic data for 45,645 primary arthroplasties and 8,400 revision surgeries from 1998 to 2018. The average recorded Charlson Comorbidity Index is 0.98. Average length of stay prior to home or care facility discharge decreased from 5.00 days in 2001 to 3.00 days in 2018. The average 30-day and 90-day mortality rates for 2018 were 0. 18% and 0.28%, respectively. Home discharge increased from 30.1% to 79.0% from 2001–2018. The values for these parameters are varied across the seven sites. Conclusion. The PAR can be used to develop best practices, analyze health-care economics, and promote evidence-based medicine. We are also developing a platform for registry development that can be exported by other hospitals that utilize an Epic-based record system. For any tables or figures, please contact the authors directly

Aims. The primary aim of this paper was to outline the processes involved in building the Partners Arthroplasty Registry (PAR), established in April 2016 to capture baseline and outcome data for patients undergoing arthroplasty in a regional healthcare system. A secondary aim was to determine the quality of PAR’s data. A tertiary aim was to report preliminary findings from the registry and contributions to quality improvement initiatives and research up to March 2019. Methods. Structured Query Language was used to obtain data relating to patients who underwent total hip or knee arthroplasty (THA and TKA) from the hospital network’s electronic medical record (EMR) system to be included in the PAR. Data were stored in a secure database and visualized in dashboards. Quality assurance of PAR data was performed by review of the medical records. Capture rate was determined by comparing two months of PAR data with operating room schedules. Linear and binary logistic regression models were constructed to determine if length of stay (LOS), discharge to a care home, and readmission rates improved between 2016 and 2019. Results. The PAR captured 16,163 THAs and TKAs between April 2016 and March 2019, performed in seven hospitals by 110 surgeons. Manual comparison to operating schedules showed a 100% capture rate. Review of the records was performed for 2,603 random operations; 2,298 (88.3%) had complete and accurate data. The PAR provided the data for three abstracts presented at international conferences and has led to preoperative mental health treatment as a quality improvement initiative in the participating institutions. For primary THA and TKA surgeries, the LOS decreased significantly (p < 0.001) and the rate of home discharge increased significantly (p < 0.001) between 2016 and 2019. Readmission rates did not correlated with the date of surgery (p = 0.953). Conclusion. The PAR has high rates of coverage (the number of patients treated within the Partners healthcare network) and data completion and can be used for both research purposes and quality improvement. The same method of creating a registry that was used in the PAR can be applied to hospitals using similar EMR systems. Cite this article: Bone Joint J 2020;102-B(7 Supple B):90–98

Since the introduction of the first National Arthroplasty Register in Sweden in 1975, many other countries have tried to adopt the successful Scandinavian system. However, not all have overcome the political and practical difficulties of establishing a working register. We have surveyed the current registries to establish the key factors required for an effective database. We have received detailed information from 15 arthroplasty registers worldwide. The legal conditions under which they operate together with the methods of collection and handling of the data differ widely, but the fulfilment of certain criteria is necessary achieve a high degree of completeness of the data to ensure the provision of statistically relevant information

The Norwegian Arthroplasty Register (NAR) started collecting data on total hip arthroplasty (THA) in 1987. Very long-term results of implants for THA are scarce. We aimed to show long-term results for the three most used femoral stems, operated from 1987. We included the uncemented Corail femoral stem (n=66,309) and the cemented Exeter stem (n=35,050) both of which are currently in frequent use. In addition, we included the Charnley stem (n=32,578, in use until 2014). To ensure comparable conditions, stems fixated with low viscosity cement and stems revised due to infections were excluded. Differences in risk of revision (all reasons and stem revisions) were assessed with Kaplan-Meier and Cox regression analyses with adjustment for possible confounding from age, sex and diagnosis (OA, other). Stem revision was defined as a revision caused by loosening of the stem, dislocation, osteolysis in the femur, or periprosthetic femur fracture, and in which the femoral component was removed or exchanged. The median and max follow-up for Corail, Exeter and Charnley were 6.3 (33.1), 8.0 (34.2) and 13.1 (34.3) respectively. Thirty years survival estimates for Corail, Exeter and Charnley stems were 88.6% (CI:85.8–90.9%), 86.7% (83.7–89.2%) and 87.1% (85.4–88.5%) respectively with stem revision as endpoint, and 56.1% (CI:53.1–59.1%), 73.3% (70.5–76.1%) and 80.2% (78.4–82.0%) with all THA revisions as endpoint. Compared to the Corail, the Exeter (HRR=1.3, CI:1.2–1.4) and the Charnley (HRR=1.9, CI:1.7–2.1) had a significant higher risk of stem revision. Women 75 years and older had better results with the cemented stems. Analyses accounting for competing risk from other causes of revision did not alter the findings. The uncemented Corail stem performed well in terms of stem revisions for stem-related revision causes compared to two frequently used cemented stems with very long follow-up. The differences between the three stems were small

Introduction: An arthroplasty database, such as the Swedish Hip Registry, provides a crude means of quality control over the sizable number of prosthetic implants available on the market today. It provides relatively rapid feedback on the performance of orthopaedic devices and surgical techniques, allowing inferior devices and methods to be discontinued. The maintenance of an arthroplasty register is inexpensive and of enormous benefit to the patient. At present, there is no nationwide arthroplasty register in operation in the Republic of Ireland. Aim: To develop an arthroplasty register which prospectively captures all clinical, radiographic and medical outcome data on patients undergoing surgery in our unit. Materials and methods We are using an existing computer software programme (Bluespier Patient Manager) to capture our information, although our database is stored independently of this. Data recorded includes medical outcome scores (WOMAC and MOS SF-36), patient data, operative details (including type of prostheses used and operative technique employed), inpatient course, and any postoperative events. For revision procedures, additional data such as location of bony defects (Gruen zones) and acetabular bone loss (Paprosky classification) are also recorded. Follow up in a special Joint Register Clinic is at six months, two years and every five years thereafter for primary procedures. This is reduced to every two years in the case of revision procedures. To date, a pilot study involving four surgeons has prospectively captured data on 82 patients undergoing both primary and revision procedures in our unit. We aim to enrol all our patients in the register from July 2005, increasing the amount of data collected, which we hope will subsequently benefit patients undergoing hip and knee arthroplasty in the future

Aims. This study compares the re-revision rate and mortality following septic and aseptic revision hip arthroplasty (rTHA) in registry data, and compares the outcomes to previously reported data. Methods. This is an observational cohort study using data from the German Arthroplasty Registry (EPRD). A total of 17,842 rTHAs were included, and the rates and cumulative incidence of hip re-revision and mortality following septic and aseptic rTHA were analyzed with seven-year follow-up. The Kaplan-Meier estimates were used to determine the re-revision rate and cumulative probability of mortality following rTHA. Results. The re-revision rate within one year after septic rTHA was 30%, and after seven years was 34%. The cumulative mortality within the first year after septic rTHA was 14%, and within seven years was 40%. After multiple previous hip revisions, the re-revision rate rose to over 40% in septic rTHA. The first six months were identified as the most critical period for the re-revision for septic rTHA. Conclusion. The risk re-revision and reinfection after septic rTHA was almost four times higher, as recorded in the ERPD, when compared to previous meta-analysis. We conclude that it is currently not possible to assume the data from single studies and meta-analysis reflects the outcomes in the ‘real world’. Data presented in meta-analyses and from specialist single-centre studies do not reflect the generality of outcomes as recorded in the ERPD. The highest re-revision rates and mortality are seen in the first six months postoperatively. The optimization of perioperative care through the development of a network of high-volume specialist hospitals is likely to lead to improved outcomes for patients undergoing rTHA, especially if associated with infection. Cite this article: Bone Joint J 2024;106-B(6):565–572

This article considers some of the problems of the interpretation of information from other national arthroplasty registers when setting up a new register. In order for the most useful information to be available from registers much international co-operation is required between all those responsible for the design of registers as well as those who gather, assess and publish the data

Aims. The current evidence comparing the two most common approaches for reverse total shoulder arthroplasty (rTSA), the deltopectoral and anterosuperior approach, is limited. This study aims to compare the rate of loosening, instability, and implant survival between the two approaches for rTSA using data from the Dutch National Arthroplasty Registry with a minimum follow-up of five years. Methods. All patients in the registry who underwent a primary rTSA between January 2014 and December 2016 using an anterosuperior or deltopectoral approach were included, with a minimum follow-up of five years. Cox and logistic regression models were used to assess the association between the approach and the implant survival, instability, and glenoid loosening, independent of confounders. Results. In total, 3,902 rTSAs were included. A deltopectoral approach was used in 54% (2,099/3,902) and an anterosuperior approach in 46% (1,803/3,902). Overall, the mean age in the cohort was 75 years (50 to 96) and the most common indication for rTSA was cuff tear arthropathy (35%; n = 1,375), followed by osteoarthritis (29%; n = 1,126), acute fracture (13%; n = 517), post-traumatic sequelae (10%; n = 398), and an irreparable cuff rupture (5%; n = 199). The two high-volume centres performed the anterosuperior approach more often compared to the medium- and low-volume centres (p < 0.001). Of the 3,902 rTSAs, 187 were revised (5%), resulting in a five-year survival of 95.4% (95% confidence interval 94.7 to 96.0; 3,137 at risk). The most common reason for revision was a periprosthetic joint infection (35%; n = 65), followed by instability (25%; n = 46) and loosening (25%; n = 46). After correcting for relevant confounders, the revision rate for glenoid loosening, instability, and the overall implant survival did not differ significantly between the two approaches (p = 0.494, p = 0.826, and p = 0.101, respectively). Conclusion. The surgical approach used for rTSA did not influence the overall implant survival or the revision rate for instability or glenoid loosening. Cite this article: Bone Joint J 2023;105-B(9):1000–1006

Aims. The primary objective of this registry-based study was to compare patient-reported outcomes of cementless and cemented medial unicompartmental knee arthroplasty (UKA) during the first postoperative year. The secondary objective was to assess one- and three-year implant survival of both fixation techniques. Methods. We analyzed 10,862 cementless and 7,917 cemented UKA cases enrolled in the Dutch Arthroplasty Registry, operated between 2017 and 2021. Pre- to postoperative change in outcomes at six and 12 months’ follow-up were compared using mixed model analyses. Kaplan-Meier and Cox regression models were applied to quantify differences in implant survival. Adjustments were made for patient-specific variables and annual hospital volume. Results. Change from baseline in the Oxford Knee Score (OKS) and activity-related pain was comparable between groups. Adjustment for covariates demonstrated a minimally greater decrease in rest-related pain in the cemented group (β = -0.09 (95% confidence interval (CI) -0.16 to -0.01)). Cementless fixation was associated with a higher probability of achieving an excellent OKS outcome (> 41 points) (adjusted odds ratio 1.2 (95% CI 1.1 to 1.3)). The likelihood of one-year implant survival was greater for cemented implants (adjusted hazard ratio (HR) 1.35 (95% CI 1.01 to 1.71)), with higher revision rates for periprosthetic fractures of cementless implants. During two to three years’ follow-up, the likelihood of implant survival was non-significantly greater for cementless UKA (adjusted HR 0.64 (95% CI 0.40 to 1.04)), primarily due to increased revision rates for tibial loosening of cemented implants. Conclusion. Cementless and cemented medial UKA led to comparable improvement in physical function and pain reduction during the initial postoperative year, albeit with a greater likelihood of achieving excellent OKS outcomes after cementless UKA. Anticipated differences in early physical function and pain should not be a decisive factor in the choice of fixation technique. However, surgeons should consider the differences in short- and long-term implant survival when deciding which implant to use. Cite this article: Bone Jt Open 2024;5(5):401–410

Aim. National Joint Replacement Registries, which are important sources for periprosthetic joint infection (PJI) data, report an average PJI incidence ranging from 0.5 to 2.0%. Unfortunately, national registries including the Dutch Arthroplasty Register (LROI), are not specifically designed to register PJI. In the Netherlands, the LROI is a nationwide population-based registry with an overall completeness of more than 95%. 3. To ensure usability and reliability of PJI data from the LROI, it is important to evaluate the quality and completeness of these data. From 2013 onwards, eight hospitals in the South-East of the Netherlands, collected their PJI data in a detailed regional infection cohort (RIC), specifically designed for this purpose. This study aimed to determine the accuracy and completeness of PJI registration (hip and knee arthroplasty) in the LROI, by comparing the LROI with the RIC. Method. All patients registered with an acute PJI in the RIC between 2014–2018 were selected for the study and were matched with the LROI. According to the Workgroup of American Musculoskeletal Infections Society (MSIS), an acute PJI was defined as at least two phenotypically identical pathogens, isolated in cultures from at least two separate tissues, obtained from the affected peri-prosthetic tissue during the DAIR treatment (debridement, antibiotics, irrigation, and retention). Only PJI occurring within 90 days after primary hip or knee arthroplasty were included. The LROI data and completeness was based on the entered procedures and documented reason for revision infection, which was not specially based on the MSIS criteria. After checks on missing and incorrectly data, the completeness of registration in the LROI was calculated by comparing the number of registrations in the LROI with data from the RIC (gold standard). Results. Of the 639 primary total hip and knee arthroplasty with a suspected PJI registered in the RIC between 2014–2018, 352 cases met the definition of acute PJI. The overall incidence was 1%. When compared with the LROI, 164 of these cases were also registered in the LROI as PJI revision, resulting in a 53% underestimation of PJI for the LROI. Conclusions. LROI data on acute PJI shows a significant underestimation, which is comparable to scarce other literature sources. To ensure reliability and usability of national PJI data, a specifically part of the LROI has to be designed for registering PJI similar to the regional cohort

Aim. The aim of this investigation was to compare risk of infection in both cemented and cementless hemiarthroplasty (HA) as well as total hip arthroplasty (THA) following femoral neck fracture. Methods. Data collection was performed using the German Arthroplasty Registry (EPRD) In HA and THA following femoral neck fracture fixation method was divided into cemented and cementless protheses and paired according to age, sex, body mass index (BMI), and the Elixhauser score using Mahalanobis distance matching. Results. Overall in 13,612 cases of intracapsular femoral neck fracture, with 9,110 (66.9 %) HAs and 4502 (33.1 %) THAs were analyzed. Infection rate in HA was significantly reduced in cases with use of antibiotic-loaded cement compared to cementless fixated prosthesis (p=0.013). In patients with THA no statistical difference between cemented and cementless prothesis was registered, however after one year 2.4 % of infections were detected in cementless and 2.1 % in cemented THA. In the subpopulation of HA after one year 1.9 % of infections were registered in cemented and 2.8 % in cementless HA. BMI (p=0.001) and Elixhauser-Comorbidity-Score (p<0.003) were identified as risk factors of PJI, while in THA also cemented prosthesis demonstrated within the first 30 days an increased risk (HR=2.728; p=0.010). Conclusion. The rate of infection after intracapsular femoral neck fracture was significantly reduced in patients treated by antibiotic-loaded cemented hemiarthroplasty. In particular for patients with multiple risk factors for the development of a PJI the usage of antibiotic-loaded bone cement seems to be a reasonable procedure for prevention of infection

Introduction. This community Arthroplasty Register is an individual initiative to document arthroplasty procedures performed from 2007 to date in a sample area in Cairo, Egypt. Currently, there is no published study or official documentation of the indications for arthroplasty, types of implants or the rate of total hip and knee arthroplasty (THA & TKA). Although the population of Egypt reached 80,394,000, the unofficial estimate of the rate of joint replacement is less than 10,000 per year. This rate is less than 10% of what is currently done in UK, a country with similar or even less population than Egypt. This indicates the unmet need for TKA in Egypt, where the knee OA is prevailing and there is a call for documentation and a registry. Methods. The registry sheet is 3 pages; pre-, intra- and post-operative. It is available in printed format and online as demonstrated below . www.knee-hip.com. During the registry period, there were 282 cases collected prospectively and 206 collected retrospectively. This initial analysis included only prospectively collected data of 157 TKA and 125 THA. Results. For THA, the mean age was 48 years ranging from (19–86). Female to male ratio was 1.15:1. The rate of uncemented THA was 84.8%, Cemented was 10.2% and hybrid THA was 5%. We have observed significant growth in the uncemented type of fixation. The rate of primary was 54.4 % (complex primary 26.4%), Conventional THA techniques were done for 56.15%, while computer assisted surgery was used in 43.85% of cases. For TKA, there was 71.33% primary and 19.7% complex primary, 8.97% revision arthroplasty. A female to male ratio was 2.92:1. The main indication for TKA was OA in 87.26%. Preoperative radiographic evaluation showed that 47% had severe varus and 15% had significant bone defect. Conventional TKA techniques were done for 73.2%, while computer assisted surgery was sued in 26.8 % of cases

Data of high quality are critical for the meaningful interpretation of registry information. The National Joint Registry (NJR) was established in 2002 as the result of an unexpectedly high failure rate of a cemented total hip arthroplasty. The NJR began data collection in 2003. In this study we report on the outcomes following the establishment of a formal data quality (DQ) audit process within the NJR, within which each patient episode entry is validated against the hospital unit’s Patient Administration System and vice-versa. This process enables bidirectional validation of every NJR entry and retrospective correction of any errors in the dataset. In 2014/15 baseline average compliance was 92.6% and this increased year-on-year with repeated audit cycles to 96.0% in 2018/19, with 76.4% of units achieving > 95% compliance. Following the closure of the audit cycle, an overall compliance rate of 97.9% was achieved for the 2018/19 period. An automated system was initiated in 2018 to reduce administrative burden and to integrate the DQ process into standard workflows. Our processes and quality improvement results demonstrate that DQ may be implemented successfully at national level, while minimizing the burden on hospitals.

Cite this article: Bone Jt Open 2022;3(9):716–725.

The increasing number of total hip arthroplasty (THA) used in young patients will inevitably lead to more revision procedures at younger ages, especially since the outcome of primary THA in young patients is already inferior compared to older patients. However, these data are lacking in literature. The aim of this study was to determine the survival of both acetabular and femoral components placed during primary and revision hip arthroplasty in patients under 55 years using Dutch Arthroplasty Register (LROI) data. All primary THA registered in the LROI between 2007–2018 in patients under 55 years were selected (n=25,682). Subsequent cup- and stem revision procedures were included. Kaplan-Meier survival analyses were used to estimate the survival probability of primary and revised cup- and stem components. Mean follow-up of primary cups and stems was 5.8 years (SD 3.2) and 5.9 years (SD 3.2), respectively. In total, 659 cup revision procedures and 532 stem revision procedures were registered. Most common reason for cup revision was acetabular loosening (n=163), most common reason for stem revision was femoral loosening (n=202). Primary cup survival for any reason at 10 years follow-up was 96.1% (95%CI: 95.7–96.4). For primary stems, 10 year survival for any reason was 97.1% (95%CI: 96.7–97.3). Mean follow-up of all revision procedures was 4.1 years (SD 2.9). Out of 659 cup revisions, 113 cup re-revisions were registered. Survival of revised cups, with end-point cup re-revision for any reason was 82.2% (95%CI: 78.8–85.1) at 5 years follow-up. Out of 532 stem revisions, 89 stem re-revisions were registered. For revised stems, survival at 5 year follow-up, with endpoint stem re-revision for any reason was 82.0% (95%CI: 78.2–85.2). The outcome of revised acetabular and femoral components is worrisome, with a survival of 82% at 5 years follow-up. This information is valuable to provide realistic expectations for these young patients at time of primary THA

Aim. The aim of this study was to assess the influence of the true operating room (OR) ventilation on the risk of revision due to infection after primary total hip arthroplasty (THA) reported to the Norwegian Arthroplasty Register (NAR). Method. 40 orthopedic units were included during the period 2005 – 2015. The Unidirectional airflow (UDAF) systems were subdivided into small-area, low-volume, vertical UDAF (lvUDAF) (volume flow rate (VFR) (m. 3. /hour) <=10,000 and diffuser array size (DAS) (m. 2. ) <=10); large-area, high-volume, vertical UDAF (hvUDAF) (VFR >=10,000 and DAS >=10) and Horizontal UDAF (H-UDAF). The systems were compared to conventional, turbulent ventilation (CV) systems. The association between revision due to infection and OR ventilation was assessed using Cox regression models, with adjustments for sex, age, indication for surgery, ASA-classification, method of fixation, modularity of the components, duration of surgery, in addition to year of primary THA. All included THAs received systemic, antibiotic prophylaxis. Results. 51,292 primary THAs were eligible for assessment. 575 (1.1%) of these THAs had been revised due to infection. Compared to CV, there was similar risk of revision due to infection after THA performed in ORs with lvUDAF (RR=0.9, 95 % CI: 0.7–1.1) and with H-UDAF (RR=1.3, 95 % CI: 0.9–1.8). The risk of revision due to infection after THA performed in ORs with large-area hvUDAF-systems was lower (RR=0.8, 95% CI: 0.6–0.9, p=0.01) compared to CV. Conclusions. This study indicates that large-area, high-volume, vertical UDAF systems may be superior to conventional ventilation systems as a prophylactic measure against THA infection. This emphasizes the importance of assessing the big diversity of different ventilation systems when studying effect measures

Primary uncemented femoral stems reported to the Norwegian arthroplasty register between 1987 and 2005 were included in this prospective observational study. There were 11 516 hips (9679 patients) and 14 different designs of stem. Kaplan-Meier survival probabilities and Cox regression were used to analyse the data. With aseptic loosening as the end-point, all currently used designs performed excellently with survival of 96% to 100% at ten years. With the end-point as stem revision for any cause, the long-term results of the different designs varied from poor to excellent, with survival at 15 years ranging between 29% and 97%. Follow-up for longer than seven years was needed to identify some of the poorly-performing designs. There were differences between the stems; the Corail, used in 5456 hips, was the most frequently used stem with a survival of 97% at 15 years. Male gender was associated with an increased risk of revision of × 1.3 (95% confidence interval 1.05 to 1.52), but age and diagnosis had no influence on the results. Overall, modern uncemented femoral stems performed well. Moderate differences in survival between well-performing stems should be interpreted with caution since the differences may be caused by factors other than the stem itself

Background. There are few studies of total knee replacements with cemented tibia and uncemented femur (hybrid). Previous studies have not shown any difference in revision rate between different fixation methods, but these studies had few hybrid prostheses. This study evaluates the results of hybrid knee replacements based on data from the Norwegian Arthroplasty Register (NAR). Patients and Methods. Primary total knee replacements without patella resurfacing, reported to the NAR during the years 1999–2009, were evaluated. Hinged-, posterior stabilized- and tumor prostheses were excluded. LCS- and Profix prostheses with conforming plus bearing were included. With the risk for revision at any cause as the primary end-point, 2945 hybrid knee replacements (HKR) were evaluated against 20838 cemented knee replacements (CKR). Kaplan-Meier survival analysis and Cox regression analysis with adjustment for age, sex and preoperative diagnosis were used. Results. Kaplan-Meier estimated survival at 8 years was 94.0% (95% CI: 93.6–94.4) in the CKR group and 97.0% (95% CI: 96.0–98.0) in the HKR group. The HKR group was made op of three brands of prosthesis, LCS, LCS-complete and Profix. Profix was the only brand with a statistically significant difference between cemented and hybrid fixation. Kaplan-Meier estimated survival at 8 years was 97.7% (95% CI: 96.7–98.7) in hybrid Profix group (HPG) and 95.5% (95% CI: 94.7–96.3) in the cemented Profix group (CPG). The adjusted Cox regression analysis showed a statistically significantly lower risk for revision in the HPG group (relative risk=0.44, 95% CI: 0.39–0.59, p<0.001). Mean operating time was 15 minutes longer in the CKR group. Conclusion. Survivorship at 8 years of the hybrid primary total knee replacements was the same or superior compared to cemented total knee replacements depending on prosthesis brand Hybrid fixation seems to be a safe alternative to cemented fixation in total knee replacement surgery