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Mortality and implant revision rates of hip arthroplasty in patients with osteoarthritis: registry based cohort study.

McMinn DJ, Snell KI, Daniel J, Treacy RB, Pynsent PB, Riley RD - BMJ (2012)

Bottom Line: In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group.It is not known whether these are causal relations or caused by residual confounding.Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages.

View Article: PubMed Central - PubMed

Affiliation: McMinn Centre, Edgbaston, Birmingham, UK.

ABSTRACT

Objectives: To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing.

Design: Cohort study.

Setting: National Joint Registry.

Population: About 275,000 patient records.

Main outcome measures: Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity.

Results: As there were large baseline differences in the characteristics of patients receiving cemented, uncemented, or resurfacing procedures, unadjusted comparisons are inappropriate. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Both uncemented total hip replacements and Birmingham hip resurfacings had a higher revision rate than cemented total hip replacements.

Conclusions: There is a small but significant increased risk of revision with uncemented rather than cemented total hip replacement, and a small but significant increased risk of death with cemented procedures. It is not known whether these are causal relations or caused by residual confounding. Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages. Previously, only adjusted analyses of hip implant revision rates have been used to recommend and justify use of cheaper cemented total hip implants. Our investigations additionally consider mortality rates and suggest a potentially higher mortality rate with cemented total hip replacements, which merits further investigation.

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Related in: MedlinePlus

Fig 2 Population averaged (adjusted) survival curves (with 95% confidence intervals shown by dashed lines) for men comparing cemented, uncemented, and Birmingham hip resurfacing patients, with mortality or revision as endpoint
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fig2: Fig 2 Population averaged (adjusted) survival curves (with 95% confidence intervals shown by dashed lines) for men comparing cemented, uncemented, and Birmingham hip resurfacing patients, with mortality or revision as endpoint

Mentions: We compared mortality and revision rates in all men for cemented, uncemented, and Birmingham hip resurfacing procedures. There were again baseline differences between groups: the men undergoing Birmingham hip resurfacing men were younger and a higher proportion were ASA grade 1 (47.9%) and ASA grade 2 (48.9%) (table 4). Multivariable analysis including the significant variables of age, ASA grade, and complexity of procedure, estimated that the hazard of death was 1.64 (1.33 to 2.02) times higher for the cemented group and 1.47 (1.19 to 1.82) times higher for the uncemented group when compared with Birmingham hip resurfacing (table 5). The population averaged survival curve shows that the highest probability of survival is seen for the Birmingham hip resurfacing group, with 92.1% (90.6% to 93.6%) predicted to be alive at six years, conditional on patients not undergoing revision before this time (fig 2). At six years, the probability of survival for patients who have not undergone revision is 0.044 (0.029 to 0.060) higher in those undergoing Birmingham hip resurfacing rather than cemented procedures. This suggests that, in a hypothetical scenario in which no patients undergo revision by six years, 23 men (17 to 35) need to be treated with Birmingham hip resurfacing rather than a cemented procedure to result in one less death by six years.


Mortality and implant revision rates of hip arthroplasty in patients with osteoarthritis: registry based cohort study.

McMinn DJ, Snell KI, Daniel J, Treacy RB, Pynsent PB, Riley RD - BMJ (2012)

Fig 2 Population averaged (adjusted) survival curves (with 95% confidence intervals shown by dashed lines) for men comparing cemented, uncemented, and Birmingham hip resurfacing patients, with mortality or revision as endpoint
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3375206&req=5

fig2: Fig 2 Population averaged (adjusted) survival curves (with 95% confidence intervals shown by dashed lines) for men comparing cemented, uncemented, and Birmingham hip resurfacing patients, with mortality or revision as endpoint
Mentions: We compared mortality and revision rates in all men for cemented, uncemented, and Birmingham hip resurfacing procedures. There were again baseline differences between groups: the men undergoing Birmingham hip resurfacing men were younger and a higher proportion were ASA grade 1 (47.9%) and ASA grade 2 (48.9%) (table 4). Multivariable analysis including the significant variables of age, ASA grade, and complexity of procedure, estimated that the hazard of death was 1.64 (1.33 to 2.02) times higher for the cemented group and 1.47 (1.19 to 1.82) times higher for the uncemented group when compared with Birmingham hip resurfacing (table 5). The population averaged survival curve shows that the highest probability of survival is seen for the Birmingham hip resurfacing group, with 92.1% (90.6% to 93.6%) predicted to be alive at six years, conditional on patients not undergoing revision before this time (fig 2). At six years, the probability of survival for patients who have not undergone revision is 0.044 (0.029 to 0.060) higher in those undergoing Birmingham hip resurfacing rather than cemented procedures. This suggests that, in a hypothetical scenario in which no patients undergo revision by six years, 23 men (17 to 35) need to be treated with Birmingham hip resurfacing rather than a cemented procedure to result in one less death by six years.

Bottom Line: In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group.It is not known whether these are causal relations or caused by residual confounding.Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages.

View Article: PubMed Central - PubMed

Affiliation: McMinn Centre, Edgbaston, Birmingham, UK.

ABSTRACT

Objectives: To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing.

Design: Cohort study.

Setting: National Joint Registry.

Population: About 275,000 patient records.

Main outcome measures: Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity.

Results: As there were large baseline differences in the characteristics of patients receiving cemented, uncemented, or resurfacing procedures, unadjusted comparisons are inappropriate. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Both uncemented total hip replacements and Birmingham hip resurfacings had a higher revision rate than cemented total hip replacements.

Conclusions: There is a small but significant increased risk of revision with uncemented rather than cemented total hip replacement, and a small but significant increased risk of death with cemented procedures. It is not known whether these are causal relations or caused by residual confounding. Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages. Previously, only adjusted analyses of hip implant revision rates have been used to recommend and justify use of cheaper cemented total hip implants. Our investigations additionally consider mortality rates and suggest a potentially higher mortality rate with cemented total hip replacements, which merits further investigation.

Show MeSH
Related in: MedlinePlus