Mesenchymal stem cells (MSC) have been used for bone regenerative applications as an alternative approach to bone grafting. Selecting the appropriate source of MSC is vital for the success of this therapeutic approach. MSC can be obtained from various tissues, but the most used sources of MSC are Bone marrow (BMSC), followed by adipose tissue (ASC). A donor-matched comparison of these two sources of MSC ensures robust and reliable results.

Despite the similarities in morphology and immunophenotype of donor-matched ASC and BMSC, differences existed in their proliferation and in vitro differentiation potential, particularly osteogenic differentiation that was superior for BMSC, compared to ASC. However, these differences were substantially influenced by donor variations. In vivo, although the upregulated expression of osteogenesis-related genes in both ASC and BMSC, more bone was regenerated in the calvarial defects treated with BMSC compared to ASC, especially during the initial period of healing. According to these findings, compared to ASC, BMSC may result in faster regeneration and healing, when used for bone regenerative applications.

Background

Systematic reviews disagree, but some recent studies have shown better function and less pain after operation with bipolar hemiarthroplasty compared to fixation by two screws in elderly patients operated for displaced femoral neck fractures. There is still uncertainty regarding the mortality associated with both procedures.

Background

A well conducted randomised study found similar functional results for patients with displaced femoral neck fracture comparing operation with a modern uncemented bipolar hemiarthroplasty with a cemented bipolar hemiarthroplasty. The mortality associated with the two procedures has not been sufficiently investigated.

Introduction

Infection after total hip arthroplasty is a severe complication. Controversies still exist as to the use of cemented or uncemented implants in the revision of infected THAs. Based on the data in the Norwegian Arthroplasty Register (NAR) we have studied this topic.

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.

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.