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18 years of results with cemented primary hip prostheses in the Norwegian Arthroplasty Register: concerns about some newer implants.

Espehaug B, Furnes O, Engesaeter LB, Havelin LI - Acta Orthop (2009)

Bottom Line: For stems, beyond 10 years we did not find statistically significant differences comparing Charnley with Titan, ITH, and SP stems, but the Exeter stem had better results (RR = 05). 10 prosthesis brands (9 cups in combination with 6 stems; n = 37,577) were investigated with 0-10 years of follow-up (inserted from 1998 through 2007).The analyses also showed a marked improvement in Charnley results between the periods 1987-1997 and 1998-2007.The results were, however, satisfactory according to international standards.

View Article: PubMed Central - PubMed

Affiliation: The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway. birgitte.espehaug@helse-bergen.no

ABSTRACT

Background and purpose: Few studies have compared the long-term survival of cemented primary total hip arthroplasties (THAs), and several prostheses have been used without adequate knowledge of their endurance. We studied long-term outcome based on data in the Norwegian Arthroplasty Register.

Patients and methods: The 10 most used prosthesis brands in 62,305 primary Palacos or Simplex cemented THAs reported to the Register from 1987 through 2007 were included. Survival analyses with revision as endpoint (for any cause or for aseptic loosening) were performed using Kaplan-Meier and multiple Cox regression with time-dependent covariates. Revision rate ratios (RRs) were estimated for the follow-up intervals: 0-5, 6-10, and > 10 years.

Results: 5 prosthesis brands (cup/stem combinations) (Charnley, Exeter, Titan, Spectron/ITH, Link IP/Lubinus SP; n = 24,728) were investigated with 0-20 year follow-up (inserted 1987-1997). After 18 years, 11% (95% CI: 10.6-12.1) were revised for any cause and 8.4% (7.7-9.1) for aseptic loosening. Beyond 10 years of follow-up, the Charnley cup had a lower revision rate due to aseptic loosening than Exeter (RR = 1.8) and Spectron (RR = 2.4) cups. For stems, beyond 10 years we did not find statistically significant differences comparing Charnley with Titan, ITH, and SP stems, but the Exeter stem had better results (RR = 05). 10 prosthesis brands (9 cups in combination with 6 stems; n = 37,577) were investigated with 0-10 years of follow-up (inserted from 1998 through 2007). The Charnley cup had a lower revision rate due to aseptic loosening than all cups except the IP. Beyond 5 years follow-up, the Reflection All-Poly cup had a 14 times higher revision rate. For stems, beyond 5 years the Spectron-EF (RR = 6.1) and Titan (RR = 5.5) stems had higher revision rates due to aseptic loosening than Charnley. The analyses also showed a marked improvement in Charnley results between the periods 1987-1997 and 1998-2007.

Interpretation: We observed clinically important differences between cemented prosthesis brands and identified inferior results for previously largely undocumented prostheses, including the commonly used prosthesis combination Reflection All-Poly/ Spectron-EF. The results were, however, satisfactory according to international standards.

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Related in: MedlinePlus

A graphical representation of the relationship between year of operation (1987–2002) and the log revision rate ratio with aseptic loosening as endpoint for all prostheses (a), Charnley prostheses (b), and all prostheses excluding Charnley (c). The graphs show 95% confidence intervals, together with results of a linear trend test and a test of non-linearity in the effect of year of operation. The graph is calibrated with the log revision rate ratio set to zero at the mean year of operation. The horizontal line shows the reference level.
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Figure 0006: A graphical representation of the relationship between year of operation (1987–2002) and the log revision rate ratio with aseptic loosening as endpoint for all prostheses (a), Charnley prostheses (b), and all prostheses excluding Charnley (c). The graphs show 95% confidence intervals, together with results of a linear trend test and a test of non-linearity in the effect of year of operation. The graph is calibrated with the log revision rate ratio set to zero at the mean year of operation. The horizontal line shows the reference level.

Mentions: To investigate whether the adjusted log RRs changed with year of operation, we fitted an extended Cox model based on generalized additive models for survival data with penalized splines (Hastie and Tibshirani 1990). This smoothing method makes no assumptions about the shape of the association, and therefore permits estimation of non-linearities. The graphs (Figure 6) were calibrated so that the log RR was set to zero at the mean year of operation. A horizontal line was added to show this reference level. The graphs are presented with 95% confidence intervals, together with the results of a linear trend test and a test of non-linearity in the effect of year of operation on survival. To ensure at least 5 years of follow-up, only THAs operated before 2003 were included in this analysis.


18 years of results with cemented primary hip prostheses in the Norwegian Arthroplasty Register: concerns about some newer implants.

Espehaug B, Furnes O, Engesaeter LB, Havelin LI - Acta Orthop (2009)

A graphical representation of the relationship between year of operation (1987–2002) and the log revision rate ratio with aseptic loosening as endpoint for all prostheses (a), Charnley prostheses (b), and all prostheses excluding Charnley (c). The graphs show 95% confidence intervals, together with results of a linear trend test and a test of non-linearity in the effect of year of operation. The graph is calibrated with the log revision rate ratio set to zero at the mean year of operation. The horizontal line shows the reference level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823190&req=5

Figure 0006: A graphical representation of the relationship between year of operation (1987–2002) and the log revision rate ratio with aseptic loosening as endpoint for all prostheses (a), Charnley prostheses (b), and all prostheses excluding Charnley (c). The graphs show 95% confidence intervals, together with results of a linear trend test and a test of non-linearity in the effect of year of operation. The graph is calibrated with the log revision rate ratio set to zero at the mean year of operation. The horizontal line shows the reference level.
Mentions: To investigate whether the adjusted log RRs changed with year of operation, we fitted an extended Cox model based on generalized additive models for survival data with penalized splines (Hastie and Tibshirani 1990). This smoothing method makes no assumptions about the shape of the association, and therefore permits estimation of non-linearities. The graphs (Figure 6) were calibrated so that the log RR was set to zero at the mean year of operation. A horizontal line was added to show this reference level. The graphs are presented with 95% confidence intervals, together with the results of a linear trend test and a test of non-linearity in the effect of year of operation on survival. To ensure at least 5 years of follow-up, only THAs operated before 2003 were included in this analysis.

Bottom Line: For stems, beyond 10 years we did not find statistically significant differences comparing Charnley with Titan, ITH, and SP stems, but the Exeter stem had better results (RR = 05). 10 prosthesis brands (9 cups in combination with 6 stems; n = 37,577) were investigated with 0-10 years of follow-up (inserted from 1998 through 2007).The analyses also showed a marked improvement in Charnley results between the periods 1987-1997 and 1998-2007.The results were, however, satisfactory according to international standards.

View Article: PubMed Central - PubMed

Affiliation: The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Norway. birgitte.espehaug@helse-bergen.no

ABSTRACT

Background and purpose: Few studies have compared the long-term survival of cemented primary total hip arthroplasties (THAs), and several prostheses have been used without adequate knowledge of their endurance. We studied long-term outcome based on data in the Norwegian Arthroplasty Register.

Patients and methods: The 10 most used prosthesis brands in 62,305 primary Palacos or Simplex cemented THAs reported to the Register from 1987 through 2007 were included. Survival analyses with revision as endpoint (for any cause or for aseptic loosening) were performed using Kaplan-Meier and multiple Cox regression with time-dependent covariates. Revision rate ratios (RRs) were estimated for the follow-up intervals: 0-5, 6-10, and > 10 years.

Results: 5 prosthesis brands (cup/stem combinations) (Charnley, Exeter, Titan, Spectron/ITH, Link IP/Lubinus SP; n = 24,728) were investigated with 0-20 year follow-up (inserted 1987-1997). After 18 years, 11% (95% CI: 10.6-12.1) were revised for any cause and 8.4% (7.7-9.1) for aseptic loosening. Beyond 10 years of follow-up, the Charnley cup had a lower revision rate due to aseptic loosening than Exeter (RR = 1.8) and Spectron (RR = 2.4) cups. For stems, beyond 10 years we did not find statistically significant differences comparing Charnley with Titan, ITH, and SP stems, but the Exeter stem had better results (RR = 05). 10 prosthesis brands (9 cups in combination with 6 stems; n = 37,577) were investigated with 0-10 years of follow-up (inserted from 1998 through 2007). The Charnley cup had a lower revision rate due to aseptic loosening than all cups except the IP. Beyond 5 years follow-up, the Reflection All-Poly cup had a 14 times higher revision rate. For stems, beyond 5 years the Spectron-EF (RR = 6.1) and Titan (RR = 5.5) stems had higher revision rates due to aseptic loosening than Charnley. The analyses also showed a marked improvement in Charnley results between the periods 1987-1997 and 1998-2007.

Interpretation: We observed clinically important differences between cemented prosthesis brands and identified inferior results for previously largely undocumented prostheses, including the commonly used prosthesis combination Reflection All-Poly/ Spectron-EF. The results were, however, satisfactory according to international standards.

Show MeSH
Related in: MedlinePlus