The Norwegian Arthroplasty Register (NAR) started collecting data on total hip arthroplasty (THA) in 1987. Very long-term results of implants for THA are scarce. We aimed to show long-term results for the three most used femoral stems, operated from 1987.

We included the uncemented Corail femoral stem (n=66,309) and the cemented Exeter stem (n=35,050) both of which are currently in frequent use. In addition, we included the Charnley stem (n=32,578, in use until 2014). To ensure comparable conditions, stems fixated with low viscosity cement and stems revised due to infections were excluded. Differences in risk of revision (all reasons and stem revisions) were assessed with Kaplan-Meier and Cox regression analyses with adjustment for possible confounding from age, sex and diagnosis (OA, other). Stem revision was defined as a revision caused by loosening of the stem, dislocation, osteolysis in the femur, or periprosthetic femur fracture, and in which the femoral component was removed or exchanged.

The median and max follow-up for Corail, Exeter and Charnley were 6.3 (33.1), 8.0 (34.2) and 13.1 (34.3) respectively. Thirty years survival estimates for Corail, Exeter and Charnley stems were 88.6% (CI:85.8–90.9%), 86.7% (83.7–89.2%) and 87.1% (85.4–88.5%) respectively with stem revision as endpoint, and 56.1% (CI:53.1–59.1%), 73.3% (70.5–76.1%) and 80.2% (78.4–82.0%) with all THA revisions as endpoint. Compared to the Corail, the Exeter (HRR=1.3, CI:1.2–1.4) and the Charnley (HRR=1.9, CI:1.7–2.1) had a significant higher risk of stem revision. Women 75 years and older had better results with the cemented stems. Analyses accounting for competing risk from other causes of revision did not alter the findings.

The uncemented Corail stem performed well in terms of stem revisions for stem-related revision causes compared to two frequently used cemented stems with very long follow-up. The differences between the three stems were small.

Aim

Previous publications have suggested that the incidence of revisions due to infection after THA is increasing. We performed updated time-trend analyses of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004–2018.

Aim

In recent years, many studies on revision for infection after arthroplasty have been published. In national arthroplasty registers, revision for infection is defined as surgical debridement, with or without removal or exchange of the entire or parts of the prosthesis due to deep infection, and should be reported to the register immediately after surgery. The diagnosis of infection is made at the surgeon's discretion, based on pre- and perioperative assessment and evaluation, and is not to be corrected to the register based on peroperative bacterial cultures. Due to this lack of validation, the rate of revision for infection will only be an approximation of the true rate of periprosthetic joint infection (PJI). Our aim was to validate the reporting of infection after total hip arthroplasty, and to assess if revisions for infection actually represented true PJI.

Young patients are at increased risk of revision after primary THA (THA). The bearing surface may be of importance for the longevity of the joint.

We aimed to compare the risk of revision of primary stemmed cementless THA with MoM and CoC with metal-on-highly-crosslinked-polyethylene (MoXLP) bearings in patients between 20–54 years.

From NARA, we included 2,153 MoM, 4,120 CoC and 10,329 MoXLP THA operated between 1995 and 2017. Kaplan-Meier estimator was used for calculation of THA survivorship and Cox regression to estimate the hazard ratio (HR) of revision (95% CI) due to any and specific causes. MoXLP was reference.

The median follow-up was 10.3 years for MoM, 6.6 years for CoC and 4.8 years for MoXLP. 15 years postoperatively the Kaplan-Meier survival estimates were 80% (78–83%) for MoM, 92% (91–93%) for CoC and 94% (93–95%) for MoXLP. The 0–2, 2–7 and 7–15 years adjusted HRs of revision by any cause were 1.4 (0.9–2.4), 3.2 (2.1–5.1) and 3.9 (1.9–7.9) for MoM and 1.1 (0.8–1.4), 1.0 (0.7–1.3) and 2.5 (1.3–4.8) for CoC bearings. After 7–15 years follow-up, the unadjusted HR of revision due to aseptic loosening was 5.4 (1.2–24) for MoM and 4.2 (0.9–20) for CoC THA. MoM and CoC had a 7–15 year adjusted HR of revision due to ‘other’ causes of 4.8 (1.6–14) and 2.1 (0.8–5.8).

MoXLP bearings were associated with better survival than MoM and CoC bearings, mainly because of lower risk of revision due to aseptic loosening and ‘other’ causes.

Aim

The aim of this study was to assess the influence of the true operating room (OR) ventilation on the risk of revision due to infection after primary total hip arthroplasty (THA) reported to the Norwegian Arthroplasty Register (NAR).

Background

Periprosthetic joint infection (PJI) after knee arthroplasty surgery remains a serious complication. Yet, there is no international consensus on the surgical treatment of PJI. The purpose was to assess the prosthesis survival rates, risk of re-revision, and mortality rate following the different surgical strategies (1-stage or 2-stage implant revision, and irrigation and debridement (IAD) with implant retention) used to treat PJI.

Introduction

Periprosthetic osteolysis resulting in aseptic loosening is a leading cause for total hip arthroplasty (THA) failure. Individuals vary in their susceptibility to osteolysis, and it is thought that heritable factors contribute to this variation. We conducted two genome-wide association studies to identify genetic risk loci associated with osteolysis and genetic risk loci associated with time to prosthesis failure due to osteolysis.

There is an ongoing discussion on what bearing surfaces to use in different age groups of total hip replacement patients.

We report results from uncemented total hip arthroplasty using ceramic on ceramic bearings reported to the Norwegian Arthroplasty Register in the period 1997–2014.

Kaplan Meier and Cox regression analysis adjusting for age, gender and diagnosis was used to assess prosthesis survival at 10 and 15 years after primary operation and to report relative risk of revision. Endpoint was any revision. Comparison with the cemented Charnley prosthesis (n=17180), with metal-on-polyethylene articulations from the same time period was done. Results in age groups <55, 55–64, 65–74, >=75 were investigated.

The following femur/cup combinations were used; Filler/Igloo (n=2590), Corail/Pinnacle (n=783), Corail/Duraloc (n=467), SCP Unique/Trilogy (n=363), Polar/R3 (n=253), ABGII/ABGII (n=131), other combinations (n=339). Alumina bearing was used in 3807 hips and Alumina-Zirconium composite bearings in 1119 hips. The overall ten and fifteen years unadjusted Kaplan Meier survivals were 94.8 % and 92.0 % respectively with no statistically significant difference between the brands. The cemented Charnley hip arthroplasty had 93.6 % survival at 15 years, and was not statistically significant different from the uncemented ceramic/ceramic group. The 10 years survival in the age groups <55, 55–64, 65–74, >=75 for the uncemented ceramic/ceramic group was 93.7%, 95.3%, 96.0% and 95.4% respectively with no difference between the uncemented brands and the cemented Charnley prosthesis. We found less revisions in patients >=75 in the Charnley group. In the ceramic on ceramic group 11 head fractures and 3 liner fractures were reported.

The 15 years result of uncemented hip replacement with ceramic on ceramic bearing was good, and not different from the Charnley cemented arthroplasty in the age groups <75 years.

Aim

To see what surgical strategy was used in treating infected total hip arthroplasties (THA), relative to bacterial findings, level of inflammation, length of antibiotic treatment (AB) and re-revisions. Further, to assess the results of treatment after three months and one year.

Summary

Particulate wear debris with different chemical composition induced similar periprosthetic tissue reactions in patients with loosened uncemented and cemented titanium hip implants, which suggests that osteolysis can develop independent of particle composition.

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.

Objectives: The major objective of the present study was to investigate the risk of revision of infection after primary total knee replacements (TKR) in patients with rheumatoid arthritis (RA) during a 13-year period. We wished to compare RA patients with OA patients in order to detect differences in the risk of revision for infection, and to compare changes in the risk for the two patient groups over time. Furthermore we studied the time from primary implantation to revision for infection in the two groups.

Patients and Methods: From January 1994 to June 2008, 2482 primary TKRs in patients with RA and 25189 in OA patients were identified in the Norwegian Arthroplasty Register. Kaplan-Meier survival curves, with revision for infection as the endpoint, were constructed. Cox regression analyses were performed to calculate relative risk (RR) of revision for infection according to diagnosis, age, gender, year of surgery (from 1994 through 2000 and from 2001 to June 2008) and time of revision related to the time of primary TKR. All relative risks were adjusted for the other variables.

Results: The 5-year revision rate for infection of TKR was 1.1% in RA patients and 0.5% in OA patients. Rheumatoid arthritis patients had a 1.7 (95%CI 1.2–2.6) times higher risk of revision for infection compared to the control group (OA patients). The patients who had TKR surgery in the later period had a decreased risk of revision for infection (RR 0.72, 95%CI 0.53–0.98) compared to the time period 1994–2000. Furthermore, the risk of revision for late infection in RA patients, increased compared to OA from 4 years after the index operation.

Conclusion: Patients with RA undergoing total knee replacement surgery were at a higher risk of revision for prosthetic joint infection and had a higher risk of late infections leading to revision, than patients with OA. These findings emphasizes the importance of preoperative management and optimizing preventive strategies, especially in this patient group.

Background and Purpose: The purpose of the present study was to assess the risk for revision due to deep infection for primary uncemented total hip arthroplasties (THAs) reported to the Norwegian Arthroplasty Register (NAR) over the period 1987–2007.

Methods: All primary uncemented THAs reported to NAR from the period 1987–2007 were studied. Adjusted Cox regression analyses with first revision due to deep infection as the end-point were performed. Changes in the revision rate as a function of year of operation were investigated, as was impact of risk factors (gender, age, type of diagnosis, duration of surgery, operation room ventilation and systemic antibiotic prophylaxis) on risk for revision due to deep infection.

Results: 14,348 primary uncemented THAs met the inclusion criteria. 97 THAs had been revised due to deep infection (5-year survival 99.56). Risk for revision due to deep infection increased through the period studied. Compared to the uncemented THAs implanted 1987–1992, the risk for revision due to infection was 1.2 times higher (95%CI 0.6–2.4, p=0.6) for those implanted 1993–1997, 1.4 times (95%CI 0.7–2.9, p=0.3) for 1998–2002, and 5.3 times (95%CI 2.6–10.7, p=< 0.001) for 2003–2007. The increase in risk for revision due to infection for primary uncemented THAs was most pronounced after the year 2000. No risk factor registered had any statistically significant impact on risk for revision due to infection in this study.

Interpretation: The results of this study indicate an increase in incidence of deep infection after uncemented THAs during the period 1987–2007. Concomitant changes in confounding factors, however, complicate the interpretation of these results.

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: 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.

There has been no general agreement about the use of uncemented hip prostheses in patients with rheumatoid arthritis (RA). In the present study we compared the results for the cemented and uncemented stem that most commonly had been used in RA patients in the Norwegian Arthroplasty Register.

MATERIAL AND Methods: All hospitals in the country participate and report their primary and revision operations of RA patients to the register. This group constitutes 3.5% of the patients in the register. For the present study we included primary prosthesis operations in RA patients during 1987–2005, where either the Corail or the Charnley stem, the most commonly used uncemented and cemented stems, had been used. We calculated survival by the Kaplan-Meier method and by Cox multiple regression with adjustment for age and gender.

Results: The 10 years survival of the total hip prostheses were 81 % in the uncemented group and 89 % in the cemented group. However, the revisions of the uncemented prostheses were mainly performed due to cup problems. With revision of stem for any reason as end-point, the 10-year survival was 98% for the fully HA-coated uncemented Corail stem and 91% for the cemented Charnley stem. In the Cox regression, the risk for revision of the Charnley stem was 3.4 times increased compared to the Corail (95% CI: 1.43–8.06. P< 0.006). Also revision due to aseptic stem loosening was statistically significant increased for the Charnley stem, whereas there was no significant difference concerning revision due to dislocation or periprosthetic fracture.

Conclusions: Both stems had a 10-years survival better than 90%, and the uncemented stem had excellent results in RA patients. However, the uncemented total hip prostheses had inferior results compared to the cemented total hip prostheses due to problems with the uncemented cups that had been used in association with this uncemented stem.

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.

We reviewed 96 consecutive cementless total hip replacements with four different designs; 21 PCA, 25 Harris Galante Porous/Harris Galante I (stem/cup), 25 Profile Porocoat/Tri-Lock Plus (stem/cup) and 25 Profile HA-coated/Tri-Lock Plus (stem/cup). The operations were performed in the period 1984 to 1991. Median follow-up ranged from 12 to 16 years in the four groups. Mean linear wear rates ranged from 0,17 to 0,21 mm/year in the four groups, and there were no statistically significant differences between the groups (p=0,9). Moderate or extensive osteolysis was found in 46 of the 96 included hips. The association between wear and extent of osteolysis was statistically significant (p=0,006). We found poor twelve-year survival of the primary prostheses in all four groups (50–70%), mainly due to revisions because of wear of the polyethylene liner and/or osteolysis. The sparsely documented Profile/Tri-Lock Plus systems did not perform statistically significantly better than the PCA and the HG. The poor long term results with these uncemented total hip arthroplasties illustrate the necessity of regular radiographic evaluation in order to detect osteolysis and liner-failure which both generally are asymptomatic until catastrophic failure appears.