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.

Aims

To compare the functional outcome, health-related quality of life (HRQoL), and satisfaction of patients who underwent primary total hip arthroplasty (THA) and a single debridement, antibiotics and implant retention (DAIR) procedure for deep infection, using either the transgluteal or the posterior surgical approach for both procedures.

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.

We report the five-year outcome of a randomised controlled trial which used radiostereometric analysis (RSA) to assess the influence of surface oxidised zirconium (OxZr, Oxinium) on polyethylene wear in vivo.

A total of 120 patients, 85 women and 35 men with a mean age of 70 years (59 to 80) who were scheduled for primary cemented total hip arthroplasty were randomly allocated to four study groups. Patients were blinded to their group assignment and received either a conventional polyethylene (CPE) or a highly cross-linked (HXL) acetabular component of identical design. On the femoral side patients received a 28 mm head made of either cobalt-chromium (CoCr) or OxZr.

The proximal head penetration (wear) was measured with repeated RSA examinations over five years. Clinical outcome was measured using the Harris hip score.

There was no difference in polyethylene wear between the two head materials when used with either of the two types of acetabular component (p = 0.3 to 0.6). When comparing the two types of polyethylene there was a significant difference in favour of HXLPE, regardless of the head material used (p < 0.001).

In conclusion, we found no advantage of OxZr over CoCr in terms of polyethylene wear after five years of follow-up. Our findings do not support laboratory results which have shown a reduced rate of wear with OxZr. They do however add to the evidence on the better resistance to wear of HXLPE over CPE.

Cite this article: Bone Joint J 2015;97-B:1463–9.

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.

We performed a randomised controlled trial comparing computer-assisted surgery (CAS) with conventional surgery (CONV) in total knee replacement (TKR). Between 2009 and 2011 a total of 192 patients with a mean age of 68 years (55 to 85) with osteoarthritis or arthritic disease of the knee were recruited from four Norwegian hospitals. At three months follow-up, functional results were marginally better for the CAS group. Mean differences (MD) in favour of CAS were found for the Knee Society function score (MD: 5.9, 95% confidence interval (CI) 0.3 to 11.4, p = 0.039), the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales for ‘pain’ (MD: 7.7, 95% CI 1.7 to 13.6, p = 0.012), ‘sports’ (MD: 13.5, 95% CI 5.6 to 21.4, p = 0.001) and ‘quality of life’ (MD: 7.2, 95% CI 0.1 to 14.3, p = 0.046). At one-year follow-up, differences favouring CAS were found for KOOS ‘sports’ (MD: 11.0, 95% CI 3.0 to 19.0, p = 0.007) and KOOS ‘symptoms’ (MD: 6.7, 95% CI 0.5 to 13.0, p = 0.035). The use of CAS resulted in fewer outliers in frontal alignment (> 3° malalignment), both for the entire TKR (37.9% vs 17.9%, p = 0.042) and for the tibial component separately (28.4% vs 6.3%, p = 0.002). Tibial slope was better achieved with CAS (58.9% vs 26.3%, p < 0.001). Operation time was 20 minutes longer with CAS. In conclusion, functional results were, statistically, marginally in favour of CAS. Also, CAS was more predictable than CONV for mechanical alignment and positioning of the prosthesis. However, the long-term outcomes must be further investigated.

Cite this article: Bone Joint J 2014; 96-B:609–18.

We welcome letters to the Editor concerning articles that have recently been published. Such letters will be subject to the usual stages of selection and editing; where appropriate the authors of the original article will be offered the opportunity to reply.

We evaluated the rates of survival and cause of revision of seven different brands of cemented primary total knee replacement (TKR) in the Norwegian Arthroplasty Register during the years 1994 to 2009. Revision for any cause, including resurfacing of the patella, was the primary endpoint. Specific causes of revision were secondary outcomes.

Three posterior cruciate-retaining (PCR) fixed modular-bearing TKRs, two fixed non-modular bearing PCR TKRs and two mobile-bearing posterior cruciate-sacrificing TKRs were investigated in a total of 17 782 primary TKRs. The median follow-up for the implants ranged from 1.8 to 6.9 years. Kaplan-Meier 10-year survival ranged from 89.5% to 95.3%. Cox’s relative risk (RR) was calculated relative to the fixed modular-bearing Profix knee (the most frequently used TKR in Norway), and ranged from 1.1 to 2.6. The risk of revision for aseptic tibial loosening was higher in the mobile-bearing LCS Classic (RR 6.8 (95% confidence interval (CI) 3.8 to 12.1)), the LCS Complete (RR 7.7 (95% CI 4.1 to 14.4)), the fixed modular-bearing Duracon (RR 4.5 (95% CI 1.8 to 11.1)) and the fixed non-modular bearing AGC Universal TKR (RR 2.5 (95% CI 1.3 to 5.1)), compared with the Profix. These implants (except AGC Universal) also had an increased risk of revision for femoral loosening (RR 2.3 (95% CI 1.1 to 4.8), RR 3.7 (95% CI 1.6 to 8.9), and RR 3.4 (95% CI 1.1 to 11.0), respectively). These results suggest that aseptic loosening is related to design in TKR.

Cite this article: Bone Joint J 2013;95-B:636–42.

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.

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).

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.