Thank you for inviting us to this meeting. We will briefly try to outline some aspects of the Norwegian Arthroplasty Register.

I will start (KLIKK) with the main objects of the registry, I will (KLIKK) delineate our methods of data validation, (KLIKK) the range of publications (KLIKK) and finally examples of our findings. Then, Dr Havelin will continue (KLIKK) with a discussion on surgeons compliance (KLIKK), reporting procedures (KLIKK) and economy.

But first, you need a short introduction to our patient cohort. KLIKK. This is Norway, in the northernmost part of Europe. KLIKK. The Norwegian Arthroplasty Register is situated in Bergen, at the west coast. From here we survey the joint replacement activities in the country. The size of the country is not too small, but it’s sparsely habitated. There are only about 4.5 million Norwegians (KLIKK) Conviniently, we all have our own and unique national identification number. This number is very helpful in linking primary and revision procedures in the joint replacement registry. Health services (KLIKK) are predominantly public and about 500 orthopaedic surgeons, like this one here, serve the population.

The main object of the registry since the startup in 1987, has been the identification of inferior implants, techniques, bone cements and routines as early as possible. To be able to do this, the implant must be clearly inferior. When such implants are identified, the orthopaedic community are noticed, and they are adviced to stop using the inferiorly performing implants. (KLIKK) Here are some examples of components and a bone cement that were abandoned due to early registry results.

The cooperation of surgeons, the simple forms and the local routines for registration are essential for receiving valuable data. Furthermore, one of the most important reasons for good quality of data in the register database is probably the well-qualified and stable secretarial manpower. Systematic and continous efforts have been made to minimize the occurence of missing or erroneous data in the register database. When errors are identified, the forms are returned to the hospital for completion. KLIKK The number of operations reported to the arthroplasty register and to the patient register, are compared on a regular basis. Comparing the two databases for the period 1999-2002, we found a 98-99% completeness in registry database on hip and knee implants. Registration of revisions was even higher. (KLIKK) Validation of results has also been done by comparing data with data from the National Institute for Hospital Research (KLIKK) and with local data from reporting hospitals. Finally, data directly from patients through quetionnaires have been compared to the registry data.

Hip and knee procedures constitute 95% of the procedures reported. (KLIKK) While registration is high in hip and knee procedures, it is much lower in less common procedures. For instance, only 52% of the primary wrist-prosthesis in the Norwegian Patient Register, were registered in our database. The low registration of course, make these data less valuable. (KLIKK) Also, we have found a relatively poor registration of removal revisions, also in hip and knee arthroplasties.

Based on data received, studies on a wide range of topics have been published. These include implant survivorship, epidemiology of joint reconstruction surgery, results of different revision strategies, mortality, effect of antibiotics in bone cement and systemically, and functional outcome, economy and so on.

The incidence KLIKK of total knee arthroplasty has been doubled since the registration of knee prostheses started in 1994. In 2005, the incidence of primary TKA was 67. A slight increase is evident also in THA, (KLIKK) and the incidens was 162 in the year of 2005. The proportion of revisions to primary replacements, have been stable throughout the period.

By 2005, 114 000 hip prostheses procedures were registered of which 14% were revisions. (KLIKK) Our reporting surgeons use cemented THA in about 80 % of the patients. The proportion of all-uncemented THA has been relatively stable at just below 15% since the registry started in 1987. Hybrids and reversed hybrids together constitute 5%. (KLIKK) In TKA, nonresurfaced patella predominates among the TKA, unicondylar prostheses constitute close to 20% of the knee prostheses operations. The use of patellar resurfacing is becoming increasingly less popular.

This slide represents revision causes in total hip arthroplasty. As we can see, the proportion (KLIKK) of revisions due to aseptic loosening of cup and stem, are falling, whereas (KLIKK) revisions due to dislocation and wear-related problems are increasing. The so-called revision burden has been relatively stable around 14% which is less than some countries and higher than others.

The curve on the left shows the results of cemented THA according to the period of implantation. The results of prostheses implanted in the early 1990ies, are slightly, but significantly inferior to those implanted the years 1987 to 1990. This corresponds to the time of conversion of surgical approach from the transfemoral Charnley to the direct lateral approach and also to the time of the disastrous Boneloc bone cement which was used in approximately 1400 patients. The results of uncemented THA have improved over the years, but are still clearly inferior to the cemented prostheses in the registry. The end-point in these analyses was exchange or removal of any part of he total hip, including the acetabular liner. Also with aseptic loosening as endpoint…and in young patients…, the overall results with uncemented THA are clearly inferior to the cemented total hips. The uncemented stems do quite well whereas the cups do not.

Since registration of knee prostheses started in 1994, a total of 21 535 TKA was registered by the year 2004. The registration completeness was good. The revision burden in knee arthroplasty was 9%. There were no significant differences between total knees with or without patellar resurfacing. The survival of unicondylar arthroplasties was significantly lower than for the total knees. Furthermore, the last generation unicondylar prostheses has so far not proved to be superior to the older designs in our material.

This was a very superficial summary of results from the Norwegian Arthroplasty register. It seems the registration (KLIKK) has become everyday routine for all orthopaedic surgeons, and (KLIKK) we are receiving high quality data for prospective observational studies… Dr Havelin will continue with other aspects to the registry. (KLIKK) Thank you for your attention.