The 2012 Otto Aufranc Award: The interpretation of metal ion levels in unilateral and bilateral hip resurfacing.
Clin Orthop Relat Res
; 471(2): 377-85, 2013 Feb.
Article
en En
| MEDLINE
| ID: mdl-22930211
ABSTRACT
BACKGROUND:
The interpretation of metal ion concentrations and their role in clinical management of patients with metal-on-metal implants is still controversial. QUESTIONS/PURPOSES:
We questioned whether patients undergoing hip resurfacing with no clinical problems could be differentiated from those with clinical (pain, loss of function) and/or radiographic (component malpositioning, migration, bone loss), problems based on metal ion levels, and if there was a threshold metal level that predicted the need for clinical intervention. Furthermore, we asked if patient and implant factors differed between these functional groups.METHODS:
We retrospectively identified 453 unilateral and 139 bilateral patients with ion measurements at minimum followup of 12 months (mean, 4.3 years; range, 1-12.9 years). Patients were designated as well functioning or poorly functioning based on strict criteria. The acceptable upper levels within the well-functioning group were determined from the 75th percentile plus 1.5× interquartile range. The sensitivity and specificity of these levels to predict clinical problems were calculated.RESULTS:
Well-functioning group ions were lower than the poorly functioning group ion levels. The acceptable upper levels were chromium (Cr) 4.6 µg/L, cobalt (Co) 4.0 µg/L unilateral and Cr 7.4 µg/L, Co 5.0 µg/L bilateral. The specificity of these levels in predicting poor function was high (95%) and sensitivity was low (25%). There were more males in the well-functioning group and more females and smaller femoral components in the poorly functioning group.CONCLUSIONS:
Metal levels higher than these proposed safe upper limits can predict problems with metal-on-metal resurfacings and are important parameters in the management of at-risk patients. LEVEL OF EVIDENCE Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Distinciones y Premios
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Falla de Prótesis
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Artroplastia de Reemplazo de Cadera
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Articulación de la Cadera
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Prótesis de Cadera
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Metales
Tipo de estudio:
Guideline
/
Observational_studies
/
Prognostic_studies
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Risk_factors_studies
Límite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Año:
2013
Tipo del documento:
Article