Hip international : the journal of clinical and experimental research on hip pathology and therapy
National registration of hemiarthroplasties after hip fractures has been established in both Norw... more National registration of hemiarthroplasties after hip fractures has been established in both Norway and Sweden. We aimed to investigate differences in demographics, choice of implant selection, surgical approaches, and reoperations between the Norwegian Hip Fracture Register (NHFR) and the Swedish Hip Arthroplasty Register (SHAR). As part of the Nordic Arthroplasty Register Association (NARA) project a common hemiarthroplasty dataset has been established. 36,989 primary hemiarthroplasties (HAs) for acute hip fractures reported to NHFR (n = 12,761) and SHAR (n = 24,228) for the period 2005-2010 were included. Cemented prostheses were used in 78% of the operations in Norway and in 95% of the patients in Sweden. In Norway HAs almost exclusively had bipolar design (98%), whereas in Sweden HAs with unipolar design were used in 42% of the cases. Monoblock (non-modular) prostheses were uncommon, but still more frequently used in Sweden than in Norway (6.9% and 2.1% respectively). The later...
The motivating example for this paper comes from a distributed health data network, the Internati... more The motivating example for this paper comes from a distributed health data network, the International Consortium of Orthopaedic Registries (ICOR), which aims to examine risk factors for orthopedic device failure for registries around the world. Unfortunately, regulatory, privacy, and propriety concerns made sharing of raw data impossible, even if de-identified. Therefore, this article describes an approach to extraction and analysis of aggregate time-to-event data from ICOR. Data extraction is based on obtaining a survival probability and variance estimate for each unique combination of the explanatory variables at each distinct event time for each registry. The extraction procedure allows for a great deal of flexibility; models can be specified after the data have been collected, for example, modeling of interaction effects and selection of subgroups of patients based on their values on the explanatory variables. Our analysis models are adapted from models presented elsewhere - but...
Background and purpose The number of national arthroplasty registries is increasing. However, the... more Background and purpose The number of national arthroplasty registries is increasing. However, the methods of registration, classification, and analysis often differ. Methods We combined data from 3 Nordic knee arthroplasty registers, comparing demographics, methods, and overall results. Primary arthroplasties during the period 1997–2007 were included. Each register produced a dataset of predefined variables, after which the data were combined and descriptive and survival statistics produced. Results The incidence of knee arthroplasty increased in all 3 countries, but most in Denmark. Norway had the lowest number of procedures per hospital—less than half that of Sweden and Denmark. The preference for implant brands varied and only 3 total brands and 1 unicompartmental brand were common in all 3 countries. Use of patellar button for total knee arthroplasty was popular in Denmark (76%) but not in Norway (11%) or Sweden (14%). Uncemented or hybrid fixation of components was also more fr...
e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine differen... more e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine different groups of disease. Factors which have previously been shown to be associated with increased risk of revision, such as male gender, young age, or certain types of uncemented prosthesis, showed important differences between the diagnostic groups. Without adjustment for these factors we observed
The Journal of bone and joint surgery. American volume, Jan 17, 2014
Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorshi... more Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorship following total knee arthroplasty. However, the benefit of mobile-bearing total knee arthroplasty remains unproven. Both mobile-bearing and fixed-bearing total knee arthroplasty implants are available in posterior-stabilized and non-posterior-stabilized designs. With the latter, the implant does not recreate the function of the posterior cruciate ligament (PCL) with a posterior-stabilizing cam mechanism. The purpose of the present study was to compare mobile-bearing, non-posterior-stabilized devices with fixed-bearing, non-posterior-stabilized devices used in total knee arthroplasty through a novel multinational study design. Through the use of a distributed health data network, primary total knee arthroplasties performed for osteoarthritis from 2001 to 2010 were identified from six national and regional total joint arthroplasty registries. Multivariate meta-analysis was performed with...
The Journal of bone and joint surgery. American volume, Jan 17, 2014
The regulation of medical devices has attracted controversy recently because of problems related ... more The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival pr...
The Journal of bone and joint surgery. British volume, 2004
We present the results for 4762 revision total hip arthroplasties with no previous infection in t... more We present the results for 4762 revision total hip arthroplasties with no previous infection in the hip, which were reported to the Norwegian Arthroplasty Register between 1987 and 2003. The ten-year failure rate for revised prostheses was 26% (95% CI 25 to 26). Cox regression analyses were undertaken separately for acetabular and femoral revision components. Cemented revision components without allograft was the reference category. For acetabular components, we found a significantly reduced risk of failure for uncemented revisions both with (relative risk (RR) = 0.66; 95% CI 0.43 to 0.99) and without (RR = 0.37; 95% CI 0.22 to 0.61) allograft. For femoral components, we found a significantly reduced risk of failure for uncemented revisions, both with (RR = 0.27; 95% CI 0.16 to 0.46) and without (RR = 0.22; 95% CI 0.11 to 0.46) unimpacted allograft. This reduced risk of failure also applied to cemented revision components with allograft (RR = 0.53; 95% CI 0.33 to 0.84) and with impa...
Background: We used the Nordic Arthroplasty Register Association database to evaluate whether age... more Background: We used the Nordic Arthroplasty Register Association database to evaluate whether age, sex, preoperative diagnosis, fixation, and implant design influence the risk of revision arthroplasty due to periprosthetic fracture within two years from operation of a primary total hip replacement.
Background: The aim of this study was to give results of elbow arthroplasty for a relatively larg... more Background: The aim of this study was to give results of elbow arthroplasty for a relatively large population and compare different prosthesis brands and different patient subgroups. Methods: Between 1994 and 2006, 562 total elbow replacement operations were reported to the Norwegian Arthroplasty Register. Revisions of prostheses were shown using Kaplan-Meier failure curves, and risk of revision was calculated using Cox regression analysis. Results: The overall 5-and 10-year failure rates were 8% and 15%, respectively. There were only minor differences between the different implants. Patients who developed traumatic arthritis after fracture had the worst prognosis compared with inflammatory arthritis (P ¼ .005). Risk of revision was also increased when the ulnar component was inserted without cement (P ¼ .02.) Conclusions: Good results in terms of prosthesis survival were obtained with total elbow arthroplasty, although results were worse than for knee-and hip arthroplasties. The best results were achieved in patients with inflammatory arthritis. Level of evidence: Level 2; prospective cohort study.
Register, we have assessed the survival of 17 323 primary Charnley hip prostheses in patients wit... more Register, we have assessed the survival of 17 323 primary Charnley hip prostheses in patients with osteoarthritis based upon the type of cement used for the fixation of the implant.
The Journal of Bone and Joint Surgery (American), 2006
Background: Interest in unicompartmental knee arthroplasty has recently increased in the United S... more Background: Interest in unicompartmental knee arthroplasty has recently increased in the United States, making a firm understanding of the indications for this procedure important. The purpose of this study was to examine the cost-effectiveness of unicompartmental knee arthroplasty compared with total knee arthroplasty in elderly low-demand patients.
The Journal of Bone and Joint Surgery (American), 2010
Background: Internal fixation and arthroplasty are the two main options for the treatment of disp... more Background: Internal fixation and arthroplasty are the two main options for the treatment of displaced femoral neck fractures in the elderly. The optimal treatment remains controversial. Using data from the Norwegian Hip Fracture Register, we compared the results of hemiarthroplasty and internal screw fixation in displaced femoral neck fractures.
The purpose of the present article was to compare the results of primary total hip arthroplasty (... more The purpose of the present article was to compare the results of primary total hip arthroplasty (THA) done because of developmental dysplasia of the hip (DDH) with the results of THA done because of idiopathic coxarthrosis (osteoarthritis) using data from the nationwide Norwegian Arthroplasty Register (NAR). In the period from 1987 to 2003, 84 871 primary THAs were reported to the NAR. Of these, 6347 (7.5%) were performed because of sequelae after DDH, 788 (0.9%) because of sequelae after DDH with complete dislocation of the femoral head, and 59 774 (71.0%) because of idiopathic coxarthrosis. The results of THAs after DDH were the same as those of THAs after idiopathic coxarthrosis after adjustments for younger age and for the use of more uncemented prostheses in patients with DDH.
Journal of Bone and Joint Surgery-british Volume, 2001
W e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine differ... more W e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine different groups of disease. Factors which have previously been shown to be associated with increased risk of revision, such as male gender, young age, or certain types of uncemented prosthesis, showed important differences between the diagnostic groups. Without adjustment for these factors we observed an increased risk of revision in patients with paediatric hip diseases and in a small heterogeneous 'other' group, compared with patients with primary osteoarthritis. Most differences were reduced or disappeared when an adjustment for the prognostic factors was made. After adjustment, an increased relative risk (RR) of revision compared with primary osteoarthritis was seen in hips with complications after fracture of the femoral neck (RR = 1.3, p = 0.0005), in hips with congenital dislocation (RR = 1.3, p = 0.03), and in the heterogenous 'other' group. The analyses were also undertaken in a more homogenous subgroup of 16 217 patients which had a Charnley prosthesis implanted with high-viscosity cement. The only difference in this group was an increased risk for revision in patients who had undergone THR for complications after fracture of the femoral neck (RR = 1.5, p = 0.0005).
Hip international : the journal of clinical and experimental research on hip pathology and therapy
National registration of hemiarthroplasties after hip fractures has been established in both Norw... more National registration of hemiarthroplasties after hip fractures has been established in both Norway and Sweden. We aimed to investigate differences in demographics, choice of implant selection, surgical approaches, and reoperations between the Norwegian Hip Fracture Register (NHFR) and the Swedish Hip Arthroplasty Register (SHAR). As part of the Nordic Arthroplasty Register Association (NARA) project a common hemiarthroplasty dataset has been established. 36,989 primary hemiarthroplasties (HAs) for acute hip fractures reported to NHFR (n = 12,761) and SHAR (n = 24,228) for the period 2005-2010 were included. Cemented prostheses were used in 78% of the operations in Norway and in 95% of the patients in Sweden. In Norway HAs almost exclusively had bipolar design (98%), whereas in Sweden HAs with unipolar design were used in 42% of the cases. Monoblock (non-modular) prostheses were uncommon, but still more frequently used in Sweden than in Norway (6.9% and 2.1% respectively). The later...
The motivating example for this paper comes from a distributed health data network, the Internati... more The motivating example for this paper comes from a distributed health data network, the International Consortium of Orthopaedic Registries (ICOR), which aims to examine risk factors for orthopedic device failure for registries around the world. Unfortunately, regulatory, privacy, and propriety concerns made sharing of raw data impossible, even if de-identified. Therefore, this article describes an approach to extraction and analysis of aggregate time-to-event data from ICOR. Data extraction is based on obtaining a survival probability and variance estimate for each unique combination of the explanatory variables at each distinct event time for each registry. The extraction procedure allows for a great deal of flexibility; models can be specified after the data have been collected, for example, modeling of interaction effects and selection of subgroups of patients based on their values on the explanatory variables. Our analysis models are adapted from models presented elsewhere - but...
Background and purpose The number of national arthroplasty registries is increasing. However, the... more Background and purpose The number of national arthroplasty registries is increasing. However, the methods of registration, classification, and analysis often differ. Methods We combined data from 3 Nordic knee arthroplasty registers, comparing demographics, methods, and overall results. Primary arthroplasties during the period 1997–2007 were included. Each register produced a dataset of predefined variables, after which the data were combined and descriptive and survival statistics produced. Results The incidence of knee arthroplasty increased in all 3 countries, but most in Denmark. Norway had the lowest number of procedures per hospital—less than half that of Sweden and Denmark. The preference for implant brands varied and only 3 total brands and 1 unicompartmental brand were common in all 3 countries. Use of patellar button for total knee arthroplasty was popular in Denmark (76%) but not in Norway (11%) or Sweden (14%). Uncemented or hybrid fixation of components was also more fr...
e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine differen... more e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine different groups of disease. Factors which have previously been shown to be associated with increased risk of revision, such as male gender, young age, or certain types of uncemented prosthesis, showed important differences between the diagnostic groups. Without adjustment for these factors we observed
The Journal of bone and joint surgery. American volume, Jan 17, 2014
Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorshi... more Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorship following total knee arthroplasty. However, the benefit of mobile-bearing total knee arthroplasty remains unproven. Both mobile-bearing and fixed-bearing total knee arthroplasty implants are available in posterior-stabilized and non-posterior-stabilized designs. With the latter, the implant does not recreate the function of the posterior cruciate ligament (PCL) with a posterior-stabilizing cam mechanism. The purpose of the present study was to compare mobile-bearing, non-posterior-stabilized devices with fixed-bearing, non-posterior-stabilized devices used in total knee arthroplasty through a novel multinational study design. Through the use of a distributed health data network, primary total knee arthroplasties performed for osteoarthritis from 2001 to 2010 were identified from six national and regional total joint arthroplasty registries. Multivariate meta-analysis was performed with...
The Journal of bone and joint surgery. American volume, Jan 17, 2014
The regulation of medical devices has attracted controversy recently because of problems related ... more The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival pr...
The Journal of bone and joint surgery. British volume, 2004
We present the results for 4762 revision total hip arthroplasties with no previous infection in t... more We present the results for 4762 revision total hip arthroplasties with no previous infection in the hip, which were reported to the Norwegian Arthroplasty Register between 1987 and 2003. The ten-year failure rate for revised prostheses was 26% (95% CI 25 to 26). Cox regression analyses were undertaken separately for acetabular and femoral revision components. Cemented revision components without allograft was the reference category. For acetabular components, we found a significantly reduced risk of failure for uncemented revisions both with (relative risk (RR) = 0.66; 95% CI 0.43 to 0.99) and without (RR = 0.37; 95% CI 0.22 to 0.61) allograft. For femoral components, we found a significantly reduced risk of failure for uncemented revisions, both with (RR = 0.27; 95% CI 0.16 to 0.46) and without (RR = 0.22; 95% CI 0.11 to 0.46) unimpacted allograft. This reduced risk of failure also applied to cemented revision components with allograft (RR = 0.53; 95% CI 0.33 to 0.84) and with impa...
Background: We used the Nordic Arthroplasty Register Association database to evaluate whether age... more Background: We used the Nordic Arthroplasty Register Association database to evaluate whether age, sex, preoperative diagnosis, fixation, and implant design influence the risk of revision arthroplasty due to periprosthetic fracture within two years from operation of a primary total hip replacement.
Background: The aim of this study was to give results of elbow arthroplasty for a relatively larg... more Background: The aim of this study was to give results of elbow arthroplasty for a relatively large population and compare different prosthesis brands and different patient subgroups. Methods: Between 1994 and 2006, 562 total elbow replacement operations were reported to the Norwegian Arthroplasty Register. Revisions of prostheses were shown using Kaplan-Meier failure curves, and risk of revision was calculated using Cox regression analysis. Results: The overall 5-and 10-year failure rates were 8% and 15%, respectively. There were only minor differences between the different implants. Patients who developed traumatic arthritis after fracture had the worst prognosis compared with inflammatory arthritis (P ¼ .005). Risk of revision was also increased when the ulnar component was inserted without cement (P ¼ .02.) Conclusions: Good results in terms of prosthesis survival were obtained with total elbow arthroplasty, although results were worse than for knee-and hip arthroplasties. The best results were achieved in patients with inflammatory arthritis. Level of evidence: Level 2; prospective cohort study.
Register, we have assessed the survival of 17 323 primary Charnley hip prostheses in patients wit... more Register, we have assessed the survival of 17 323 primary Charnley hip prostheses in patients with osteoarthritis based upon the type of cement used for the fixation of the implant.
The Journal of Bone and Joint Surgery (American), 2006
Background: Interest in unicompartmental knee arthroplasty has recently increased in the United S... more Background: Interest in unicompartmental knee arthroplasty has recently increased in the United States, making a firm understanding of the indications for this procedure important. The purpose of this study was to examine the cost-effectiveness of unicompartmental knee arthroplasty compared with total knee arthroplasty in elderly low-demand patients.
The Journal of Bone and Joint Surgery (American), 2010
Background: Internal fixation and arthroplasty are the two main options for the treatment of disp... more Background: Internal fixation and arthroplasty are the two main options for the treatment of displaced femoral neck fractures in the elderly. The optimal treatment remains controversial. Using data from the Norwegian Hip Fracture Register, we compared the results of hemiarthroplasty and internal screw fixation in displaced femoral neck fractures.
The purpose of the present article was to compare the results of primary total hip arthroplasty (... more The purpose of the present article was to compare the results of primary total hip arthroplasty (THA) done because of developmental dysplasia of the hip (DDH) with the results of THA done because of idiopathic coxarthrosis (osteoarthritis) using data from the nationwide Norwegian Arthroplasty Register (NAR). In the period from 1987 to 2003, 84 871 primary THAs were reported to the NAR. Of these, 6347 (7.5%) were performed because of sequelae after DDH, 788 (0.9%) because of sequelae after DDH with complete dislocation of the femoral head, and 59 774 (71.0%) because of idiopathic coxarthrosis. The results of THAs after DDH were the same as those of THAs after idiopathic coxarthrosis after adjustments for younger age and for the use of more uncemented prostheses in patients with DDH.
Journal of Bone and Joint Surgery-british Volume, 2001
W e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine differ... more W e studied the rates of revision for 53 698 primary total hip replacements (THRs) in nine different groups of disease. Factors which have previously been shown to be associated with increased risk of revision, such as male gender, young age, or certain types of uncemented prosthesis, showed important differences between the diagnostic groups. Without adjustment for these factors we observed an increased risk of revision in patients with paediatric hip diseases and in a small heterogeneous 'other' group, compared with patients with primary osteoarthritis. Most differences were reduced or disappeared when an adjustment for the prognostic factors was made. After adjustment, an increased relative risk (RR) of revision compared with primary osteoarthritis was seen in hips with complications after fracture of the femoral neck (RR = 1.3, p = 0.0005), in hips with congenital dislocation (RR = 1.3, p = 0.03), and in the heterogenous 'other' group. The analyses were also undertaken in a more homogenous subgroup of 16 217 patients which had a Charnley prosthesis implanted with high-viscosity cement. The only difference in this group was an increased risk for revision in patients who had undergone THR for complications after fracture of the femoral neck (RR = 1.5, p = 0.0005).
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Papers by Ove Furnes