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.

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.

Background: Annually about 9,000 patients in Norway are operated because of hip fractures. From January 2005 all these fractures should be reported to The Norwegian Hip Fracture Register, founded by the Norwegian Orthopaedic Association and operated by The Norwegian Arthroplasty Register from 1. January 2005.

Patients and methods: We have established contacts at every hospital in Norway that perform surgery for hip fractures. Immediately after the surgery the surgeon fills in a standardized form which is sent to the register once a month. On the form there are both patient- and procedure-related questions. Four and twelve months postoperatively we send a questionnaire to the patients, including the Norwegian translation of the EuroQol-5D. Patient information is linked to the Norwegian Death Register using the unique identification number assigned for each resident of Norway. We have so far included 5,668 primary hip fractures operations and 607 revision procedures including revisions to hemiprosthesis and total hip replacements (THR).

Results: After 1 year of registration 100 % of the hospitals are reporting to the register. Approximately 50 % of the patients have answered the questionnaire. Of the primary operated patients the mean age was 80.5 years and 73 % were females. 59 % of the fractures were intracapsular femoral neck fractures and approximately 2/3 of those were dislocated. 35 % of the fractures were intertrochanteric or subtrochanteric.

Intracapsular dislocated fractures: Screw fixation was used in 48 % of the hips while 46 % of the hips were operated with a hemiarthroplasty, and 4.1 % were operated with a THR. We could not find any difference in mortality between screw fixated patients and patients operated with a hemiarthroplasty.

Intertrochanteric/subtrochanteric fractures: The hip compression screw osteosynthesis was used in 88 % of the patients, 6.3 % of these had a lateral support plate. An intramedullary nail was used in 8.9 % of the patients.

Conclusion: After only one year, the reports from the surgeons were good. Taking the age and general status into consideration, also the response from the patients is satisfactory. With longer follow-up we will be able to give more information on the outcomes of hip fractures and of the different treatment. Updated analysis will be reported.

Purpose: About 1% of the children are born with neonatal hip instability (NHI). By combining data from the Medical Birth Registry of Norway (MBRN) with that of the Norwegian Arthroplasty Register (NAR), the influence of NHI on the risk for total hip arthroplasty (THA) before 37 years of age are studied.

Materials and Methods: Since 1967 medical data, included stability of the hips, on all new-borns in Norway (2 092 536 babies) have been compiled. Since 1979 all THA performed in Norway are reported to the NAR. Until 2004 85,120 primary THAs were registered, of these 492 were performed on patients under 37 years of age. These two national registries were linked by using the unique person identification number assigned to each inhabitant of Norway.

Results: Of those 20 668 born with NHI (1%), 9 had received a THA before 37 years of age (43/100 000). Since only 18 of 100 000 new-borns without NHI had had THA, new-borns with NHI had 2,5 times increased risk for having a THA before they become 37 years.

Of the 492 THA in patients younger than 37 years in the NAR, 101 THA (20.5%) were, according to the surgeon, operated because of developmental dysplasia of hip (DDH). Since 13 of these were bilateral THA, the number of patients were 88. Only 9 of these 88 DDH-patients were, however, reported to have NHI. This is surprisingly few, since their dysplasia should be anticipated to be rather severe. Does this indicate that the hip-screening for new-borns in Norway should be changed?

Conclusions: New-borns with NHI has 2.5 times increased risk for THA before the age of 37 years compared to those with stable hips at birth. The absolute risk is, however, low, only 43/100 000. Of those 88 who received THA because of DDH before 37 years, 79 had, however, reported normal hips at birth.

Background: This study was done to compare the early failure of primary cemented unicompartmental knee arthroplasties (UKA) with that of total knee arthroplasties (TKA).

Methods: The Kaplan-Meier survial-method and the Cox multiple regression model were used to compare the failure rates of the primary cemented UKAs (n=1410) and the primary cemented TKAs (patellar resurfaced) (n=2818) that were reported to the Norwegian Arthroplasty Register between 1st January 1994 and 1st April 2003.

Results: 8 years survival for UKAs was 85.2 % (95% CI: 81.5–88.9) compared to 93.0 % (91.5–94.5) for TKAs, relative revision risk (RR) 1.8 (1.4–2.4), p< 0.001. The increased revision risk in UKAs was seen in all age categories. Among the UKAs the 8 years survival showed no statistically significant difference for MOD III, Genesis uni and Oxford II. However, Duracon uni knees had, statistically significantly higher rates of revision, although the numbers of prostheses were low. Two UKAs were introduced recently and the follow up was short. After 3 years the Miller Galante uni had 82.8 % (75.6–90.0) survival compared to 93.8 (91.0–96.6) for the Oxford III knee, p< 0.002. The higher failure rates of the Miller Galante and Duracon knees were mainly due to more loosening of the tibial components. UKAs had an increased risk of revision due to pain, aseptic loosening of the tibial and femoral components and periprosthetic fractures compared to TKAs. The UKAs had a lower risk of infection compared to TKAs.

Conclusions: This prospective study has shown that the prostheses survival of cemented UKAs was not as good as for cemented TKAs. There were differences between the UKAs, but the best UKA had results inferior to the average of the TKAs.

Materials and methods: Based on data from the Norwegian Arthroplasty Register, we reviewed the results of uncemented femoral stems in Norway in the period 1987 to 1. April 2002. We compared these results to the results of the cemented Charnley monoblock stem, which still is the most commonly used femoral stem in Norway. Only prostheses used in more than one hundred hips were included. Based on these criteria, we identified a total of 7 856 primary total hip prostheses in fifteen different uncemented stems. With the Kaplan-Meier method, the survival of the primary prostheses were calculated and compared with each other and with the Charnley stem. The endpoint was revision in which the whole prostheses or the stem alone was removed or exchanged. The Cox regression analysis was used to adjust for differences in age, gender, diagnosis, former operations and profylactic antibiotics. Separate analyses for patients younger than 60 years and for stems with follow-up less than ten years were done. Reasons for revision in the uncemented Corail stem and the cemented Charnley stem was analysed.

Results: The Corail stem, wich is the most commonly used uncemented stem in Norway (n=3590), had excellent long term results. 10 years survival in patients younger than 60 years was for the Corail 97,5% and for the Charnley 90,2% (p=0,001). Reasons for revision of the Corail were in most cases pain and repeated dislocations. Aseptic loosening was the dominant cause of failure of the Charnley stem. Several uncemented stems have results which are as good as or superior to the Charnley. The Femora, the Biofit, the Parhofer and the Harris Galante stems all had inferior results. Many uncemented stems with less than 10-years of follow-up have excellent 5 years survival.

The 10 years survival of uncemented total hip arthroplasties, however was inferior to the all-cemented Charnley. Cup revisions due to aseptic loosening, and wear and/or osteolysis were the reasons for this.

Discussion: The Corail stem has excellent long term results. Several newer stems have promising short- and medium term results. Due to inferior results of unce-mented cups, however, most Norwegian orthopaedic surgeons use cemented primary hip replacements.

Aims: To assess the influence of hip disease on the risk of revision, we studied different disease groups among 53 698 primary total hip replacements (THRs) reported to the NAR between 1987 and 1999. Methods: the revision rate in the 8 most common hip diseases were compared by kaplan-meier survival analyses and cox multiple-regression. To eliminate the influence of prosthesis type a subgroup of 16217 charnley prostheses were analysed. Results: we found statistically significant differences in prosthesis survival among the hip diseases, but after adjustment for prosthesis type most of the differences disappeared. In patients ≤60 years, 59% of the prostheses were uncemented and 33% could be defined as inferior uncemented prostheses. In the charnley subgroup only complications after fracture of the femoral neck had an increased risk for revision compared to primary osteoarthritis (rr 1.5, p=0.005). 10 years survival for cemented charnley prostheses with osteoarthritis was 92.0% for patients ≤60 years and 93.5% for patients > 60 years. Conclusions: after adjustment the results for all disease groups were good. The results of thrs in disease-groups where patients are operated on at a young age were less good because these patients had often been given inferior uncemented prostheses.

Aims: The mid- and long-term results of uncemented cups are uncertain. The aim of this study was to assess their results and to compare them with the most common cemented cup, the Charnley. Material and methods: In the study we included only patients under the age of 60 that had been operated with one of the 10 most common uncemented cup brands or the Charnley cup. Only brands that had been in use for at least 6 years were included. There were only minor differences among the brands concerning age, gender and diagnosis. Survival percentages were calculated with the Kaplan-Meier method. Results: With all cup revisions (change of cup or polyethylene liner) as end-point, the overall 5 year survival probability was 97% (95% CI: 96.3 97.3) which decreased to 86% (95% CI: 84.4 Ð 87.5) at 10 years. The 10 years survival varied from 74% for the Atoll cup to 88% for the Optiþx and the Harris-Galante cup, whereas for the cemented Charnley cup the 10 years survival probability was 94%. For the uncemented cups the increase in revision risk after 6 years was mainly due to wear and osteolysis. For the HA-coated cups also aseptic loosening increased after 6 years of follow-up. Conclusion: Uncemented cups in young patients had good short-term results. At 10 years of follow-up for the investigated uncemented cup brands, the results were inferior to the Charnley cup.

Purpose: The outcome of primary total hip arthroplasty (THA) after a previous paediatric hip disease was studied in data from the Norwegian Arthroplasty Register (NAR).

Materials and Methods: 72,301 primary THAs were reported to the NAR for the period 1987 – February 2002. Of these, 5,459 (7.6%) were performed because of sequela after developmental dysplasia of hip (DDH), 737 (1.0%) because of DDH with dislocation, 961 (1.3%) because of Perthes’/ slipped femoral capital epiphysis (SFCE) and 50,369 (70%) because of primary osteoarthritis (OA). Prosthesis survival was calculated by the Kaplan-Meier method and relative risks for revision in a Cox model with adjustments for age, gender, type of systemic antibiotic, operation time, type of operating theatre and brand of prosthesis.

Results: Without any adjustments the THAs for all three groups of paediatric hip diseases had 1.4 – 2.0 times increased risk for revision compared to that of OA (p< 0.001). Due to huge differences in the studied groups, a more homogenous subset of the data had to be analysed. In this subset, only THAs with well documented prostheses, high-viscosity cements and antibiotic prophylaxis both systemically and in the cement were included (16,874 THAs). In this homogenous subset, no differences in the survivals could be detected for DDH without dislocation and for Perthes’/SFCE compared to OA. For DDH with dislocation the revision risk with all reasons for revisions as endpoint in the analyses was increased 3.3 times compared to OA (p< 0.001), 2.7 times with aseptic loosening as endpoint (p< 0.01) and 10 times with infection as endpoint (p< 0.001).

Conclusions: If well-documented THAs are used after paediatric hip diseases the results are just as good as after osteoarthritis, except for DDH with dislocation where increased revision risk is found.