Background

Tranexamic acid (TA) in total knee replacement surgery (TKR) has shown marked reduction in bleeding and blood transfusion. There are little data on TA in revision TKR. From February 2008 all patients having primary or revision TKR received TA 10mg/kg × 2. We whished to evaluate the effect and possible complications of TA.

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).

Introduction

The treatment of trochanteric and subtrochanteric fractures remains controversial, and new implants are constantly being developed trying to improve outcome and minimize the number of complications in these fractures.

In Norway the Sliding Hip Screw(SHS), with or without a Trochanteric Stabilizing Plate (TSP), is still the most commonly used implant, but worldwide nailing of these fractures is increasing. This trend, however, has not been supported by documentation of better clinical results compared to the SHS in well designed studies. Therefore, in the present study we compared the recently launched Trigen Intertan nail (Smith and Nephew) with the SHS in the treatment of trochanteric and subtrochanteric fractures.

Using data from the Norwegian Hip Fracture Register, 8639 cemented and 2477 uncemented primary hemiarthroplasties for displaced fractures of the femoral neck in patients aged > 70 years were included in a prospective observational study. A total of 218 re-operations were performed after cemented and 128 after uncemented procedures. Survival of the hemiarthroplasties was calculated using the Kaplan-Meier method and hazard rate ratios (HRR) for revision were calculated using Cox regression analyses. At five years the implant survival was 97% (95% confidence interval (CI) 97 to 97) for cemented and 91% (95% CI 87 to 94) for uncemented hemiarthroplasties. Uncemented hemiarthroplasties had a 2.1 times increased risk of revision compared with cemented prostheses (95% confidence interval 1.7 to 2.6, p < 0.001). The increased risk was mainly caused by revisions for peri-prosthetic fracture (HRR = 17), aseptic loosening (HRR = 17), haematoma formation (HRR = 5.3), superficial infection (HRR = 4.6) and dislocation (HRR = 1.8). More intra-operative complications, including intra-operative death, were reported for the cemented hemiarthroplasties. However, in a time-dependent analysis, the HRR for re-operation in both groups increased as follow-up increased.

This study showed that the risk for revision was higher for uncemented than for cemented hemiarthroplasties.

In this prospective study we studied the effect of the inclination angle of the acetabular component on polyethylene wear and component migration in cemented acetabular sockets using radiostereometric analysis.

A total of 120 patients received either a cemented Reflection All-Poly ultra-high-molecular-weight polyethylene or a cemented Reflection All-Poly highly cross-linked polyethylene acetabular component, combined with either cobalt–chrome or Oxinium femoral heads. Femoral head penetration and migration of the acetabular component were assessed with repeated radiostereometric analysis for two years. The inclination angle was measured on a standard post-operative anteroposterior pelvic radiograph. Linear regression analysis was used to determine the relationship between the inclination angle and femoral head penetration and migration of the acetabular component.

We found no relationship between the inclination angle and penetration of the femoral head at two years’ follow-up (p = 0.9). Similarly, our data failed to reveal any statistically significant correlation between inclination angle and migration of these cemented acetabular components (p = 0.07 to p = 0.9).

Background: In the Norwegian Arthroplasty Register several uncemented femoral stems have proved good or excellent survivorship. The overall results of uncemented total hip arthroplasty however, have been disappointing due to inferior results of the metal backed acetabular cups. In this study we investigated the medium-term performance of primary uncemented metal backed acetabular cups exclusively.

Methods: 9 113 primary uncemented acetabular cups in 7 937 patients operated in the period 1987–2007 were included in a prospective, population-based observational study. All were modular, metal-backed uncemented cups with ultra-high molecular weight polyethylene liners and femoral heads made of steel, cobalt chrome, or Alumina ceramics. Thus 7 different cup designs were evaluated with the Kaplan-Meier method and Cox regression analyses.

Results: Most cups performed well up to 7 years. When the end-point was cup revision due to aseptic cup loosening, the cups had a survival of 87 to 100% at 10 years. However, when the end-point was cup revision of any reason, the survival estimates were 81 to 92% for the same cups at 10 years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the metal backed cups in this study. Prostheses with Alumina heads performed slightly better than those with steel- or cobalt chrome in sub-groups.

Conclusions: Whereas most cups performed well at 7 years, the survivorship declined with longer follow-up time. Fixation was generally good. None of the metal-backed uncemented acetabular cups with UHMWPE liners investigated in the present study had satisfactory long-term results due to high rates of wear, osteolysis, aseptic loosening and dislocation. Hopefully cross-linked liner inserts will improve long term outcome in the future.

Introduction: Revision rate after THA in the younger age groups is still unacceptable high and might up to 20% after 10 years. The aim of this investigation is to evaluate risk factors for later revision in patients younger than 50 years at surgery based on the NARA database (Nordic Arthroplasty Register Association).

Materials and Methods: 14,610 primary THA from Denmark, Sweden, and Norway, operated from 1995 to 2007, were included. 49.4% was males, the diagnosis was idiopathic osteoarthrosis (OA) in 46%, childhood disease in 26%, inflammatory arthritis (IA) in 12%, non-traumatic osteonecrosis in 9% and fracture in 6%. 49% of the THA’s were uncemented, 27% cemented, 14% hybrid, and 8% were inverse hybrid THA’s. Cox multiple regression, adjusted for diagnose, age, gender, calendar year and surgical approach, was used to calculate prosthesis survival with any revision as end-point. RR= relative risk (CI= confidence interval).

Results: The overall 10-year survival was 83%. There was no difference between gender (RR=0.94 (0.82–1.07)). IA had a 37% reduced risk of revision compared with OA (RR=0.67 (0.54–0.84)), whereas there was no difference between childhood disease and primary osteoarthrosis. Overall, cemented, uncemented and reverse hybrid THA had a better survival than hybrid THA. Hybrid THA had 24% increased risk compared with cemented (RR=1.24 (1.04–1.49)). There were no difference between cementless and cemented (RR=1.07 (0.92–1.26)). Interestingly, the inverse THA had lower revision rate than cemented THA in men (RR=0.50 (0.25–0.99)). The risk for revision due to aseptic loosening was lowest in cementless THA and reduced to RR=0.55 (0.44–0.69) compared with cemented THA.

Discussion: and Conclusion: Choice of prosthetic concept for younger patients is still of debate. The present study including only patients younger than 50 years of age, showed that overall cemented, uncemented and reverse hybrid THA, had better survival than traditional hybrid. The risk for revision due to aseptic loosening was higher in cemented than cementless THA.

Introduction: In an earlier publication we analysed short-term results of total hip arthroplasty (THA) with Ceramic-on-Ceramic (C-on-C) articulations, and we found that they did not perform better than the Charnley prosthesis with a metal-on-UHMWPE articulation.

Purpose: To examine mid-term results of THA with Con-C articulations, and to compare their results with the most commonly used cemented prosthesis in our register, the Charnley.

Materials and Methods: All THAs with C-on-C articulations were uncemented and they constituted 2506 THAs.

194 of the THAs had articulations with an Alumina liner and a femoral head made of a composite of Alumina and Zirconium oxide ceramic (Biolox delta). This group had a median follow-up of only 1.1 years, and the group was therefore not included in the survival analyses.

2312 of the THAs were uncemented prostheses with Alumina-on-Alumina articulations, with a follow-up of 0–11 years (median 4.3 years). For further analyses we included only patients under the age of 80 years (n = 2209).

We compared the two most common C-on-C cup/stem combinations: Igloo/Filler (n=1402) and Trilogy/SCP (n=363), and a group of others (n= 547). Further we compared the C-on-C prostheses with cemented Charnley prostheses in patients under the age of 80 years, operated during the same time-period. We also compared the C-on-C prostheses with Charnley prostheses in a group limited to patients under the age of 60 years. Prosthesis survival was estimated by Kaplan-Meier and Cox regression analyses adjusted for age and gender.

Results: In patients under the age of 80 years the Charnley prostheses had a statistically significant higher survival than the C-on-C prostheses at 7 years (97.1% and 95.7% respectively, p=0.04). In patients under 60 years of age these analyses gave similar results, although with no statistical significant difference between Charmley and the C-on-C prostheses (p=0.06). There was no statistically significant difference in revision risk among Igloo/Filler, Trilogy/SCP, and a group of all other combinations of cup/stem with a C-on-C articulation. The most common causes for revision of the C-on-C hips were dislocation (n=18) and deep infection (n=16). 3 were revised due to a broken liner and 4 due to a broken head. Of the 194 articulations with Alumina liner and Biolox delta head, one had been revised due to fractured head.

Conclusion: With a follow up of 0–11 years, we did not find superior results of the C-on-C prostheses compared to the Charnley prosthesis. Few revisions were clearly related to failure of the articulations.

Introduction: Highly cross-linked polyethylene acetabular cups and Oxinium femoral heads were developed to reduce wear debris induced osteolysis. Laboratory tests have shown less wear with these new materials. This RSA-study was performed to compare these new materials in vivo with conventional bearing materials used in total hip arthroplasty.

Methods:150 patients were randomized to 5 groups. The patients received either a cemented Charnley mono-block stainless steel femoral stem with a 22.2 mm head or a cemented Spectron EF femoral stem with a 28 mm head. The Charnley stem articulated with a cemented Charnley Ogee acetabular cup. The Spectron EF stem was used with either cemented Reflection All-Poly EtO-sterilized ultra-high molecular weight polyethylene (UHMWPE) acetabular cups or cemented Reflection highly cross-linked polyethylene (XLPE) acetabular cups, combined with either Cobalt Chrome or Oxinium 28 mm femoral heads. Patients were followed up with repeated radiostereometric analysis (RSA) for two years to assess the rate of penetration of the femoral head into the cup (MTPM).

Results: At 2 years follow-up the mean MTPM (95 % CI) for Charnley Ogee (n=25) was 0.20 mm (0.11–0.29). For the Spectron EF femoral stem used with Reflection All-Poly UHMWPE acetabular cups the mean MTPM (CI) at 2 years was 0.40 mm (0.23–0.57) when combined with Cobalt Chrome femoral head (n=23) and 0.50 mm (0.29–0.71) when combined with Oxinium femoral head (n=16). When using the Spectron EF femoral stem with Reflection XLPE combined with Cobalt Chrome (n=27) or Oxinium (n=24) femoral head the mean MTPM (CI) at 2 years was 0.19 mm (0.10–0.28) and 0.18 mm (0.07–0.29), respectively. There were no differences in penetration between the Charnley/Ogee, XLPE/CoCr and XLPE/Oxinium groups (student t-test, p=0.5–0.8). There was no statistically significant difference between the two Reflection All-Poly UHMWPE groups (p=0.09). The groups with Reflection All-Poly cups had a statistically significant higher penetration than the three groups mentioned above (p< 0.001).

Discussion: The use of Reflection XLPE cups instead of Reflection All-Poly cups reduced femoral head penetration at 2 years. We used the Charnley Ogee cup as a reference due to a long clinical record. This cup was superior to Reflection All-Poly, but not Reflection XLPE, regarding femoral head penetration. Because the femoral head of Charnley Ogee is smaller than the Oxinium/Cobalt Chrome head it might be more clinical relevant to measure volumetric wear. The groups with Oxinium heads did not have less wear than the groups with Cobalt Chrome heads after 2 years follow-up. Further follow-up is needed to evaluate the benefits, if any, of Oxinium femoral heads in the clinical setting.

Background: The treatment of trochanteric and subtrochanteric fractures is still controversial. In Norway the most commonly used implant for these fractures is the Sliding Hip Screw (SHS), with or without a trochanteric support plate. The Intertan nail (Smith & Nephew) has been launched as a nail with improved biomechanical properties for the treatment of these fractures, but so far it has not been shown that the clinical results are superior to the traditional Sliding Hip Screw.

We wanted to investigate any differences in pain and function between the new Intertan nail and the Sliding Hip Screw in the early postoperative phase.

Materials and Methods: 665 patients older than 60 years with a trochanteric or subtrochanteric fracture were randomized to either a SHS (CHS/DHS) or an Intertan nail in 5 hospitals. For practical reasons only 315 patients (47%) were evaluated at day 5 postoperatively (163 Intertan and 152 SHS), and these patients were used for our analysis. Pain was measured using a Visual Analog Scale (VAS), and early functional mobility by the “Timed Up and Go”- test (TUG-test). T-tests and chi-square tests were used to examine differences between the groups.

Results: The average pain at rest was similar for the 2 groups (VAS 21). Pain at mobilization, however, differed, where patients operated with the Intertan nail had less pain than those operated with the SHS (VAS 47 vs. 53, p = 0.02). The difference between the implants was most pronounced for the simple two-part fractures (AO Type A1). More patients treated with the nail than with the SHS performed the TUG-test at day 5 (85/163 vs. 63/152, p = 0.06), but there was no statistically significant difference regarding the average speed the TUG-test was performed with (71 vs. 66sec, p = 0.36). The implant type did not influence the length of hospital stay.

Discussion/Conclusion: Regarding early postoperative pain and function, there seems to be similar or better results for trochanteric and subtrochanteric fractures treated with the Intertan nail compared to the SHS. The difference in measured pain level was statistically significant, but may not be clinically significant (a difference of VAS 6). We could not detect any significant differences in terms of early functional mobility between the two implants.

In our opinion it still remains to show good long-term results and acceptable complication rates before the new Intertan nail is widely taken into use. Due to the additional costs for the Intertan nail also economic aspects should be considered when choosing the implant and operative method for these fractures.

Introduction: There is an increasing interest in surface replacement arthroplasty (SRA) as an alternative to conventional THA (cTHA) in young and active patients. However, there has been considerable variability in reported outcomes. National joint registry reports have shown increased revision rates compared to cTHA. We analysed outcome measured as non-septic revision rate within two years for SRA in the NARA data base (Nordic Arthroplasty Register Association).

Materials and Methods: 1638 SRA and 163802 cTHA with age up to 73 years and a non-fracture diagnosis, operated from 1995 to 2007, were compared using Cox multiple regression including age, gender, diagnosis, nation and prosthesis type with cTHA divided into cemented, uncemented, hybrid and reversed hybrid fixation. Men below 50 years of age (460 SRA and 7185 cTHA) were analysed as a subset. The SRA cohort with a mean follow-up 1,8 years was also analysed with the same method including age, gender, diagnosis, number of performed SRA per hospital and the four most commonly used prosthesis designs. In an additional analysis femoral head diameter was added, reducing the number of cases to 1552. results are presented as relative risk (RR) with 95 % confidence interval(CI).

Results: SRA had a more than twofold increased revision risk compared to cTHA, RR=2,50 (1,67–3,70), which increased to 3,63 (2,42–5,44) when compared with all cemented THA. In the subpopulation of men below 50 years of age, there was no difference between SRA and any of the cTHA cathegories. Within the SRA group RR was reduced by male gender, RR=0,46 (0,25–0,86), in hospital performing > 70 SRA (RR=0,26, 0,11–0,60) and with use of BHR (Birmingham Hip Resurfacing) compared to all other designs (RR=0,27, 0,12–0,61). The size of the femoral head diameter had no significant influence on the early revision rate.

Discussion and Conclusion: Surface replacement arthroplasty has an increased risk of early revision compared to conventional and cemented THA except for men below 50 years of age. There is a learning curve on the hospital level. Cases with secondary osteoarthritis were comparatively few and were mainly caused by pediatric hip disease. SRA might become an alternative for young men, but our follow up is too short to determine if this indication remains in the longer perspective.

Background and purpose: Development of minimal invasive operation techniques has given unicompartemental knee arthroplasty (UKA) renewed interest. Indications for use of UKA are however debated, and short-term advantages of UKA over total knee arthroplasty (TKA) should be weighed against the higher risk of reoperation. More knowledge on long term results of pain and function after knee arthroplasties is therefore needed and was the purpose of this study.

Methods: Patient-reported pain and function were collected at least two years after the operations in postal questionnaires from 1643 osteoarthritis patients reported to the Norwegian Arthroplasty Register with intact primary TKA (n=1271) or UKA (n=372). The questionnaire contained instruments for calculation of the knee specific Knee Osteoarthritis Outcome Score (KOOS), and for quality of life (EQ-5D, post- and pre-operative). 5 subscales from KOOS were used as outcome. To incorporate an outcome for anterior knee pain an additional subscale based on 7 questions from KOOS, clinically accepted to be related to such discomfort, was calculated. Pain and satisfaction from a visual analogue scale (VAS) were also used as outcomes together with improvement in EQ-5D index score. The outcomes were measured on a scale from 0 (worst) to 100 (best) units with an argued minimal perceptible clinical difference of 8–10 units. Group differences were analysed with multiple linear regression, adjusted for confounding by age, gender, Charnley category, time since operation and preoperative EQ-5D index score.

Results: UKA performed better than TKA for the KOOS subscales Activity in Daily Living (difference in mean outcome score =−3.4,p=0.02) and Sport and Recreation (difference =−4.4,p=0.02) and for Anterior Pain (difference=−4.5,p< 0.01). The difference was also significant for the outcome Pain(VAS) but now in favour of TKA (difference=3.3,p=0.02). Motivated by the discrepancy in the results of the pain related outcomes, Anterior Pain (UKA best), Pain(VAS) (TKA best) and Pain(KOOS) (no difference) further investigation of the questions (0=best to 4=worst) used for calculation of Pain(KOOS) and Anterior Pain were performed. Patients that had undergone UKA had more often pain from the knee (difference=0.26,p< 0.01), while they had less pain when they were bending the knee fully (difference=−0.37,p< 0.01) and less problems when squatting (difference=−0.25,p< 0.01).

Interpretation: Estimated differences did not reach the level of minimal perceptible clinical difference. There are however indication of differences in the way the two treatment groups experience knee related discomfort. Even though UKA offers a lower level of pain and less problems in activities involving bending of the knee, these patients seem to experience pain from the knee more often.

Introduction: Up to now comparisons and pooling of data between the Scandinavian arthroplasty registers have been restrained by use of separate and incompatible data systems.

Purpose: To create a common Scandinavian database for hip arthroplasties and to compare demographics and results between the Scandinavian countries.

Materials and methods: For this study we selected primary total hip prostheses (THR) from 1995–2006. A common code set was made, and after de-identification of the patients’ identity, including deletion of the national civil registration numbers, Denmark, Sweden, and Norway delivered data. Kaplan-Meier and Cox multiple regression, with adjustment for diagnosis, age, and gender, were used to calculate prosthesis survival, with any revision as end-point.

Results: 280,201 operations were included (Denmark 69,242, Sweden 140,821, Norway 70,138). Female patients constituted 60% in Denmark and Sweden and 70% in Norway. In Denmark, Sweden, and Norway childhood disease constituted 3.1%, 1.8%, and 8.7% respectively. The posterior approach was used in 91% of cases in Denmark, 60% in Sweden, and 24% in Norway. Cemented THRs were applied in 46% of patients in Denmark, 89% in Sweden, and in 79% in Norway. Resurfacing hips constituted 0.5% or less in all countries.

9,596 of the 280,201 primary THRs, had been revised. Ten-years survival was 91.9% (95% CI: 91.5 – 92.3) in Denmark, 93.9% (95% CI: 93.6–94.1) in Sweden, and 92.6% (95% CI: 92.3–93.0) in Norway.

In Sweden and Norway 23% of revisions were due to dislocation, compared to 34% in Denmark. Replacement of only cup or liner constituted 29% of the revisions in Sweden, 33% in Norway, and 44% in Denmark.

Conclusion: This unique database is now functioning, and has showed differences among the countries concerning demographics, prosthesis fixation, prosthesis survival, and reasons for revisions. The large number of THRs in this database significantly enhances our perspectives for future research, especially in diagnostic- and treatment groups with too small numbers in each separate

Background: Few studies have compared long-term survival for different types of cemented primary total hip arthroplasties, and prostheses are still used without adequate knowledge of their endurance.

Patients and Methods:We compared the 10 most used prosthesis brands cemented with Palacos or Simplex in primary THAs reported to the Norwegian Arthroplasty Register in 1987–2007, totaling 62305 operations. Survival analyses with revision as endpoint (any cause or aseptic loosening) were performed with Kaplan-Meier and multiple Cox regression analyses. Risk estimates were established for different time intervals after the primary operation (0–5 years, 6–10 years, > 10 years).

Results: At 20 years, the Kaplan-Meier estimated revision per cent with any revision as endpoint was 15 % (95 % CI: 14–17), and with revision due to aseptic loosening as endpoint, 11 % (9.8–13). The adjusted revision percentage for aseptic loosening at 10 years could be established for 7 of the prostheses and varied from 0.4 % (0.0–0.8) for the Lubinus SP (I, II) to 6.6 % (4.1–9.0) for the Reflection all poly/Spectron-EF (cup/stem) combination. Only Charnley, Exeter, Titan and Spectron/ITH could be compared beyond 10 years. While long-term results were similar for these stems, Exeter (RRcup = 1.7, p = 0.001) and Spectron (RRcup = 2.4, p = 0.001) cups had higher revision rates due to aseptic loosening than Charnley cups. Comparing Charnley with prostheses with shorter follow-up, we observed an increased revision risk for aseptic loosening in the 6–10 year time interval also for Reflection all poly/Spectron-EF (RRcup = 5.5, p< 0.001; RRstem = 2.4, p< 0.001), Elite/Titan (RRcup = 7.5, p< 0.001; RRstem = 5.4, p< 0.001) and for the cup in the Reflection all poly/ITH combination (RRcup = 2.1, p = 0.03). Only the Lubinus SP had statistically significant better results than the Charnley prosthesis (RRcup = 0.2, p = 0.09; RRstem = 0.1, p = 0.01). Since several of the prostheses were introduced in recent years, analyses were also performed on operations from 1998 and onwards. Except for Lubinus SP that now had results similar to that of Charnley, differences in survivorship as compared with Charnley were enhanced. This was mainly due to a marked improvement in results for the Charnley prosthesis.

Conclusion: We observed in the Norwegian Arthroplasty Register clinically important differences among cemented prosthesis brands and identified inferior results for previously undocumented prostheses. Overall results at 20 years were, however, satisfactory according to international standards.

Background: About 60% of all cancer patients survive at least 5 years, and therefore have a risk to develop long-term effects after cancer treatment. Most research, the later years, on long-term effects after cancer treatment, has focused on cardiovascular side effects and side effects in the pelvic region. On the other hand, hardly any focus has been on possible side effects on the musclo-skeletal system, though there are multiple reasons that surviving cancer patients may develop such problems.

Aim: To determine whether cancer patients have an increased risk for receiving a total hip replacement compared to the population of Norway. Analyses are based on a linkage between The Cancer Register of Norway and The Norwegian Arthroplasty Register.

Materials and Methods: By linking these two registers we have connected all cancer diagnosis, all total hip arthroplasties and information about time of death for each patient. Data refers to 741,901 patients, divided into three groups; 652,197 patients with at least one cancer diagnose but none hip arthroplasties. 72,469 patients with at least one hip arthroplasty but no cancer diagnose. The last group of 17,235 patients have at least one cancer diagnose and at least one hip arthroplasty. From the last group 8,629 patients received a cancer diagnoses first and a total hip arthroplasty second. Statistical methods in this study were the Kaplan-Meier method, Cox regression and Standardized Incidence Ratio (SIR).

Results: Cancer patients had a slight increased risk to receive a total hip arthroplasty compared to the Norwegian population (SIR=1.13 (95% CI, 1.10–1.15)). For cancer located proximal to the pelvic area there were no significant increase in risk for hip arthroplasty, except for breast cancer (SIR=1.12 (95% CI 1.07–1.17)). Cancer located to the pelvic area (SIR=1.18 (95% CI 1.14–1.22)), lymphoma (SIR=1.29 (95% CI 1.14–1.45)) and leukaemia (SIR=1.16 (95% CI 1.17–1.31)) had an increased risk for receiving a total hip arthroplasty.

Conclusion: We found a small increase in risk for receiving total hip arthroplasty after cancer diagnose. Treatment type may affect these results. Radiation dose to the pelvic area may affect the bone structure and increase the need of arthroplasty. Future studies on effect of radiation doses and risk of receiving hip arthroplasty are planed.

The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components.

A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis.

Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups.

Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation.

Objective: To study the incidence of joint replacement procedure, arthrodesis, and synovectomy among patients with chronic inflammatory joint disease during the period 1994 to 2004.

Methods: Data from the Norwegian Arthroplasty Register was used to find the number of joint replacement procedures performed in Norway 1994 – 2004. The incidences of arthrodeses and synovectomies were obtained from the Norwegian Patient Register. Incidence rates were calculated based on age, year, and gender specific population rates for the Norwegian population, obtained from Statistics Norway.

Results: There were 8268 primary joint replacements, 3554 arthrodeses, and 5012 synovectomies performed in patients with inflammatory arthritis (IA) during the study period. A reduction in joint replacement procedures and synovectomies took place during the period 1994 to 2004, in patients with IA. For the oldest patients (80 years and older), no such trend was found. During the same time period, the incidence of joint replacements due to osteoarthritis increased. A significant reduction in the incidence of arthrodesis procedures was also found for the total study group, but not for the different subgroups.

Conclusion: The incidence of joint replacements and synovectomies among patients with chronic inflammatory joint disease decreased from 1994 to 2004. This may be the result of improved medical treatment of these patients.

Aims: To calculate one-year survival after dislocated intracapsular femoral neck fractures and to assess factors associated with increased risk of death.

Patients: 2045 patients treated for dislocated intracapsular femoral neck fractures during 2005 were registered in The Norwegian Hip Fracture Registry and were included in the present study.

Methods: Almost all hospitals in Norway reported proximal femoral fractures to the Registry using standard forms filled in by the operating surgeons. Survival was calculated using Kaplan Meier survival analyses, and the impact of factors possibly influencing the survival was estimated using Cox regression analysis. Mortality data for all patients were obtained from Statistics Norway.

Results: 2045 patients having dislocated intracapsular femoral neck fractures operated with 2 pins/screws (1071) and bipolar hemiprosthesis (974) were enrolled in the Registry during 2005. Among these, 333 patients died within the first year after the operation; 2 pins/screws (170) and bipolar hemiprosthesis (163). Factors adversely associated with survival included high age, male gender, dementia and with an increase in preoperative ASA classification. No statistically significant difference was found regarding preoperativ delay or for the two different treatment methods.

Conclusion: After one year there is no difference in risk of death between operation methods; 2 pins/screws and hemiprosthesis, for dislocated femoral neck fractures.

There is an increased early postoperative mortality (operation risk) after joint replacement surgery. This mortality is normally associated with cardiovascular events, such as deep venous thrombosis, pulmonary embolism, and ischemic heart diseases.

Our objective was to quantify the magnitude of the increased mortality and how long the mortality after an operation persists.

We focused on the early postoperative mortality after surgery for total knee and total hip replacements from the national registries in Australia and Norway, which cover more than 95% of all operations in the two nations. Only osteoarthritis patients between 50 and 80 years of age were included. A total of 244.275 patients remained for analyses.

Smoothed intensity curves were calculated for the early postoperative period. Effects of risk factors were studied using a non-parametric proportional hazards model.

The mortality was highest immediately after the operation (~1 deaths per 10.000 patients per day), and it decreased until the 3rd postoperative week. The mortality was virtually the same for both nations and both joints. Mortality increased with age and was higher for males than for females.

A possible reduction of early postoperative mortality is plausible for the immediate postoperative period, and no longer than the 3rd postoperative week.

Background: During the 1990s a change in operative technique for primary hip replacement took place in Norway. This study was designed to measure the revision rate in different time periods in cemented Charnley total hip replacements reported to the Norwegian Arthroplasty Register.

Patients and methods: 26 873 primary cemented Charnley total hip replacements reported to the Norwegian Arthroplasty Register in the time periods 1987–91, 92–96, 97–01 and 2002–05 were studied. Only hips with Palacos and Simplex cements with and without antibiotic were studied. To compare the time periods Kaplan Meier analysis was used. To adjust for differences in approach to the hip, age, sex and use of systemic antibiotic prophylaxis Cox regression was used.

Results: There was 28 % less risk of revision due to all causes in the time period 1997–01 compared to 1987–91 (RR=0.72 (95% CI 0.60–0.86), p< 0,001). There was inferior result in the time period 1992–96 compared to 1987–91, but from 1997 there has been an improvement of results due to fewer aseptic loosenings of the femoral component (RR 0.44 (95% CI 0.35–0.56), p< 0.001). There was however more luxations in the later period, and there was no improvement in revisions due to aseptic loosening of the acetabular component.

Conclusion: There has been an improvement in revision rate of the cemented Charnley prosthesis the last two time periods, due to fewer aseptic loosenings of the femoral component. The reason is probably better technique of component placement and better cementation technique. In the future prevention of luxation and better cementation technique of the acetabulum should also be emphasised.