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Ove Furnes

Publications and source records attributed to Ove Furnes.

12 recordsLinked to original sources
PubMed2006

Registration completeness in the Norwegian Arthroplasty Register.

INTRODUCTION: A high degree of registration completeness is necessary in order to obtain unbiased and accurate register-based study results. We investigated the completeness of registration in the national Norwegian Arthroplasty Register (NAR). MATERIAL AND METHODS: Registration completeness for the years 1999-2002 was calculated as a percentage, with the number of joint replacements reported to the NAR as numerator and those reported to the Norwegian Patient Register (NPR) as denominator. While the NAR received information directly from the orthopedic surgeons on a voluntary basis, the NPR, which is mandatory, received information from the electronic administrative patient records of the hospitals. RESULTS: Registration completeness in the NAR was 97% (97% for primary operations; 101% for revisions). Completeness was 98% (97%; 106%) for hip replacements, and for knee replacements it was 99% (99%; 97%). Hip and knee replacements represented 95% of all operations. However, completeness was poorer for less common joint replacements and poorest for ankle implants (82%; 40%) and wrist implants (52%; 14%). In the NAR, completeness of registration of revisions involving only removal of one or more prosthetic parts was lower than for exchange revisions for all types of joint replacement. For hip implants, 76% of the removal revisions (80% of Girdlestone procedures) were reported, and for knee implants the figure was 62%. According to NPR statistics, removal procedures accounted for 9% of all revisions of hip and knee replacements. INTERPRETATION: In the NAR, registration completeness of hip and knee replacements was high both for primary operations and exchange revisions. For some of the less common joint replacements, completeness was low and may--if not improved--compromise prosthesis survival studies. The lower registration completeness of removal revisions also needs to be improved.

Arthroplasty, Replacement↗
PubMed2006

Does cement increase the risk of infection in primary total hip arthroplasty? Revision rates in 56,275 cemented and uncemented primary THAs followed for 0-16 years in the Norwegian Arthroplasty Register.

INTRODUCTION: The cementation of a total hip prosthesis may cause bone necrosis, either by direct toxicity or by generation of heat during the polymerization process. This necrotic bone may create conditions that encourage the growth of bacteria. We compared the revision rates due to infection in primary uncemented total hip arthroplasties (THAs) with those of cemented THAs with antibiotic-loaded cement and to those of cemented THAs without antibiotic cement. METHODS: Data from the Norwegian Arthroplasty Register for the period 1987-2003 were used. To have comparable groups, we analyzed only primary THAs performed because of primary osteoarthrosis, and where both the acetabular and the femoral component of the prosthesis were either uncemented or cemented (n = 56,275). RESULTS: In total, 252 revisions due to infection were reported. Compared to the uncemented THAs (n = 5,259), the risk of revision due to infection for THAs without antibiotic cement (n = 15,802) was increased 1.8 times (CI 1.0-3.1; p = 0.04). No differences could be detected when compared to THAs with antibiotic-loaded cement (n = 35,214) (RR 1.2, CI 0.7-2.0; p = 0.5). The average operating time for uncemented THAs was 15 min less than for cemented THAs. INTERPRETATION: The risk of revision due to infection was the same for uncemented and for cemented arthroplasties with antibiotic-loaded cement, but higher for cemented arthroplasties without antibiotic cement. Our findings can be explained by reduced resistance to infection caused by the cement, which appears to be neutralized by adding antibiotic to the cement.

Aged↗
PubMed2006

Cost-effectiveness of unicompartmental and total knee arthroplasty in elderly low-demand patients. A Markov decision analysis.

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. METHODS: A Markov decision model was used to evaluate the cost-effectiveness of unicompartmental knee arthroplasty as compared with total knee arthroplasty in the elderly population. Transition probabilities were estimated from the Norwegian Arthroplasty Register and the arthroplasty literature, and costs were based on the average Medicare reimbursement for unicompartmental, tricompartmental, and revision knee arthroplasties. Outcomes were measured in quality-adjusted life-years. RESULTS: Our model showed unicompartmental knee arthroplasty to be a cost-effective strategy for this population as long as the annual probability of revision is <4%. The cost of unicompartmental knee arthroplasty must be greater than $13,500 or the cost of total knee arthroplasty must be less than $8500 before total knee arthroplasty becomes more cost-effective. CONCLUSIONS: Our model suggests that, on the basis of currently available cost and outcomes data, unicompartmental knee arthroplasty and total knee arthroplasty have similar cost-effectiveness profiles in the elderly low-demand patient population. However, several important parameters that could alter the cost-effectiveness analysis were identified; these included implant survival rates, costs, perioperative mortality and infection rates, and utility values achieved with each procedure. The thresholds identified in this study may help decision-makers to evaluate the cost-effectiveness of each strategy as further research characterizes the variables associate with unicompartmental and total knee arthroplasties and may be helpful for designing future appropriate clinical trials.

Aged↗
PubMed2005

Validation of data in the Norwegian Arthroplasty Register and the Norwegian Patient Register: 5,134 primary total hip arthroplasties and revisions operated at a single hospital between 1987 and 2003.

BACKGROUND: The usefulness of a national medical register relies on the completeness and quality of the data reported. The data recorded must therefore be validated to prevent systematic errors, which can cause bias in reports and study conclusions. PATIENTS AND METHODS: We compared the number of hip replacements reported to the Norwegian Arthroplasty Register (NAR), 1987-2003, and to the Norwegian Patient Register (NPR), 1999-2002, with data recorded at a local hospital. The date of operation and the index hip were further validated to find inaccurately recorded data in the NAR. Kaplan-Meier estimated survival curves were compared to evaluate the possible influence of missing data. RESULTS: Of 5,134 operations performed at a local hospital, 19 (0.4%) had not been reported to the NAR. Completeness of registration was poorer for revisions (1.2%) than for primary operations (0.2%). Among 86 Girdlestone revisions (removal of the prosthesis only), 9 (11%) had not been reported to the NAR. Missing data on revisions, however, had only a minor influence on survival analyses. The date of the operation had been recorded incorrectly in 56 cases (1.1%), and the index hip in 12 cases (0.2%). The surgeon was responsible for 85% of these errors. Comparisons with data reported to the NPR, 1999-2002, showed that 3.4% of operations at the local hospital had not been reported to the NPR. INTERPRETATION: Only 0.4% of the data from a local hospital was missing in the NAR, as opposed to the NPR where 3.4% was missing. The information recorded in the NAR appears to have been valid and reliable throughout the entire period, and provides an excellent basis for clinically relevant information regarding total hip arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2004

Operating time and survival of primary total hip replacements: an analysis of 31,745 primary cemented and uncemented total hip replacements from local hospitals reported to the Norwegian Arthroplasty Register 1987-2001.

BACKGROUND: Some studies have found a significant decrease in operating time as a result of standardizing programs for hip surgery. To study the influence of operating time (skin to skin) on survival of total hip replacements, we investigated the operating time in local hospitals in Norway. We have found no other large published series of THRs investigating operating time and revision. PATIENTS AND METHODS: The study was based on 31,745 primary THRs reported to the Norwegian Arthroplasty Register from 47 local hospitals during 1987-2001. Operating time was divided into 7 categories, and for each category separate Kaplan-Meier curves and adjusted failure rate ratios were calculated. RESULTS: The mean operating time for all local hospitals in Norway was 96 (68-130) min. Increasing operating volume from less than 10 THRs/hospital/year to more than 200 THRs/hospital/year was associated with a 25-min decrease in mean operating time in cemented THRs and a 35-min decrease in the case of uncemented THRs. With the operating time category of 71-90 min as reference category, cemented THRs that lasted more than 150 min had a two-fold increased (95% CI: 1.6-2.6) revision rate. For uncemented implants, the revision rate was 1.3 times higher (95% CI: 0.8-2.2). Cemented implants with operating time under 51 min and over 90 min were associated with an increased risk of revision due to aseptic loosening. Cemented implants with operating time over 150 min were associated with an increased risk of revision due to infection. INTERPRETATION: Hospitals with long operating times should consider the potential benefit of reducing these times, as this may lead to lower revision rates and increased operating volumes. Shorter operation times could be achieved by standardization programs, but one should bear in mind that for cemented implants very short operating times also increased revision risk due to aseptic loosening.

Aged↗
PubMed2003

Femoral head size is a risk factor for total hip luxation: a study of 42,987 primary hip arthroplasties from the Norwegian Arthroplasty Register.

On the basis of the Norwegian Arthroplasty Register, which has recorded nearly all primary hip prostheses and revisions in Norway since 1987, we studied risk factors for prosthesis luxation leading to revision. 7 prosthesis brand combinations used in 42,987 primary operations were included from 1987-2000. We found that femoral head size was an important risk factor; 28 mm heads led to revision more often than 32 mm ones (failure rate ratio (FRR) 4.0, 95% confidence interval (CI) 2.2-7.3). Charnley (22 mm head) performed equally well or better than the 28 mm heads. The Exeter stem and cup is the type of prosthesis on the Norwegian market with more than two femoral head sizes (26, 28, 30, 32 mm) and 26 mm heads led to revision due to luxation significantly more often than 30 mm heads (FRR 4.1, 95%CI 2.2-8.1). Old age, preoperative diagnosis, and choice of prosthesis brand combination were also important factors affecting the revision rate due to luxation. A posterior approach increased the risk of revision more than a lateral one (FRR 1.9, 95% CI 1.4-2.5). Gender, trochanteric osteotomy and duration of the operation did not affect the results.

Aged↗
PubMed2003

Antibiotic prophylaxis in total hip arthroplasty: effects of antibiotic prophylaxis systemically and in bone cement on the revision rate of 22,170 primary hip replacements followed 0-14 years in the Norwegian Arthroplasty Register.

We studied the effects of antibiotic prophylaxis, systemically and in bone cement, on the revision rate of cemented total hip arthroplasties (THAs) in data from the Norwegian Arthroplasty Register during the period 1987-2001. To have comparable groups, only THAs performed because of primary osteoarthritis, using cemented implants with documented good results, and high-viscosity cement were included. If systemic antibiotic prophylaxis had been given, only operations with cephalosporin or penicillin were selected. Cox-estimated survival relative revision risks (RR) are presented with adjustment for differences among groups in gender, age, cement brand, type of systemic antibiotic prophylaxis, type of prosthesis, type of operating room, and duration of the operation. Of 22,170 THAs studied, 696 THAs (3.1%) were revised, 440 (2.0%) for aseptic loosening and 102 (0.5%) for deep infection. We found the lowest risk of revision when the antibiotic prophylaxis was given both systemically and in the cement (15,676 THAs). Compared to this combined regime, patients who received antibiotic prophylaxis only systemically (5,960 THAs) had a 1.4 times higher revision rate with all reasons for revision as endpoint (p = 0.001), 1.3 times higher with aseptic loosening (p = 0.02) and 1.8 times higher with infection as the endpoint (p = 0.01). With the combined antibiotic regime, the results were better if antibiotics were given 4 times on the day of surgery (2,194 THAs), as compared to once (1,424 THAs) (p < 0.001), twice (2,680 THAs) (p < 0.001), or 3 times (5,522 THAs) (p = 0.02). Those who received systemic prophylaxis a single day 1, 2 or 3 times, as compared to 4 times, had a revision rate 1.8-3.5 times higher with all reasons for revision as endpoint, 1.5-3.1 times higher with aseptic loosening, and 2.7-6.8 times higher with infection. When we compared systemic prophylaxis 4 times in 1 day, no further improvement resulted in those given systemic prophylaxis for 2 days (1,928 THAs) or 3 days (717 THAs). In a subset of data including only the Charnley prosthesis, we obtained similar results. This observational study shows that the best results were recorded when antibiotic prophylaxis was given both systemically and in the bone cement, and if the systemic antibiotic was given 4 times on the day of surgery.

Adolescent↗
PubMed2002

Early postoperative mortality after 67,548 total hip replacements: causes of death and thromboprophylaxis in 68 hospitals in Norway from 1987 to 1999.

Patients in the Norwegian Arthroplasty Register with a total hip replacement (THR) have a lower long-term mortality than the age- and gender-matched Norwegian population. We analyzed the early postoperative mortality after 67,548 THR operations in 68 hospitals reported to the Norwegian Arthroplasty Register between 1987 and 1999. Data on deaths and causes of death were obtained from from Statistics Norway, and on thromboprophylaxis from a separate questionnaire sent to all hospitals. During the years 1987-2000 the 68 hospitals reported use of 6 thromboprophylaxis drugs and 24 different combinations of drugs and stockings. In 1988, only 3 of 29 hospitals reported use of low molecular weight heparin (LMWH), but in 1999, 67 of the 68 hospitals used LMWH. In the first postoperative week, the daily mortality was about 2.5 deaths per 10,000 THR patients. By the 70th postoperative day, the daily mortality had declined to about 0.57 deaths per 10,000 patients. The daily mortality of the age- and gender-matched Norwegian population was 0.95 deaths per 10,000 individuals. Early postoperative mortality increased with age, was higher in men than women, and was usually due to vascular disease. We found only a slight reduction in the 60-day postoperative mortality during the period 1987-1999. All underlying diagnoses for a prosthesis operation had a higher 60-day postoperative mortality than primary osteoarthrosis.

Aged↗
PubMed2002

Early failures among 7,174 primary total knee replacements: a follow-up study from the Norwegian Arthroplasty Register 1994-2000.

We studied primary total knee replacements (TKRs), reported to the Norwegian Arthroplasty Register, operated on between 1994 and 2000. A Cox multiple regression model was used to evaluate differences in survival among the prosthesis brands, their types of fixation, and whether or not the patella was resurfaced. In Norway in 1999, the incidence of knee prosthesis operations was 35 per 100,000 inhabitants. Cement was used as fixation in 87% of the knees, 10% were hybrid and 2% uncemented implants. Bicompartmental (not resurfaced patella) prostheses were used in 65% of the knees. With all revisions as endpoint, no statistically significant differences in the 5-year survival were found among the cemented tricompartmental prostheses brands: AGC 97% (n 279), Duracon 99% (n 101), Genesis I 95% (n 654), Kinemax 98% (n 213) and Tricon 96% (n 454). The bicompartmental LCS prostheses had a 5-year survival of 97% (n 476). The type of meniscal bearing in LCS knees had no effect on survival. Survival with revision for all causes as endpoint showed no differences among types of fixation, or bi- or tricompartmental prostheses. Pain alone was the commonest reason for revision of cemented bicompartmental prostheses. The risk of revision because of pain was 5.7 times higher (p < 0.001) in cemented bicompartmental prostheses than cemented tricompartmental ones, but the revisions mainly involved insertion of a patellar component. In tricompartmental prostheses the risk of revision because of infection was 2.5 times higher than in bicompartmental ones (p = 0.03). Young age (< 60) and the sequelae after a fracture increased the risk of revision. The 5-year survival of the 6 most used cemented tricompartmental knee prostheses brands varied between 95% and 99%, but the differences were not statistically significant. There were more revisions because of pain in bicompartmental than in tricompartmental knees. In tricompartmental knees, however, there were more revisions because of an infection. The relatively few patients with uncemented and hybrid implants showed no improvements in results compared to cemented knee prostheses.

Adolescent↗