Retrospective analysis of adverse reactions to metal-on-metal lumbar disc arthroplasties in 378 consecutive patients.

Abstract

BACKGROUND: Spinal disc arthroplasty implants are primarily manufactured from metal/polymer materials. Biological reaction to wear debris ultimately requires clinical studies for assessment. Research into biological reaction of metal-on-polyethylene and metal-on-metal wear debris of knee and hip arthroplasties is well progressed as opposed to similar research on spinal arthroplasties. 

MATERIALS AND METHOD: The Swedish Spine Register provides a resource for the evaluation of adverse events and clinical outcome to lumbar metal-on-metal total disc replacements. The resource will be used for a retrospective analysis of the cases in this study. The material reviewed consists of a total of 378 Swedish patients treated between October 2003 and May 2009 (181 male, 197 female); average age was 39.2 years. By means of a questionnaire, 94% of the patients were followed up after two years and 88% after five years 

RESULTS: No reported cases were found of suspected or confirmed metal hypersensitivity or pseudotumors. This may be due to symptom-producing pseudotumors being extremely rare and the difficulty to form questions which would be able to indicate the presence of the adverse outcome 

CONCLUSION: Based on the results from this study, it can be concluded that the results do not exclude the possibility that patients might have non-symptomatic pseudotumors, but being non-symptomatic, the authors doubt the importance and relevance of further investigating those isolated cases