This website is dedicated to providing public information regarding DePuy Hip recall and other related information to the recall. None of the information on this site is intended to be formal legal or medical advice, nor should any information on this site be construed as advice that should be used in lieu of information from your attorney or physician.
Sunday, January 19, 2014
Blood Cobalt concentration was a positive and significant risk factor for joint failure
BMJ Open. 2013 Mar 12;3(3). pii: e001541. doi: 10.1136/bmjopen-2012-001541.
The clinicalimplications of elevatedbloodmetalionconcentrations in asymptomaticpatients with MoMhipresurfacings: a cohortstudy.
Joint Replacment Unit, University Hospital of North Tees, Middlesbrough, UK.
To determine whether elevatedblood cobalt (Co) concentrations are associated with early failure of metal-on-metal (MoM) hipresurfacings secondary to adverse reaction to metal debris (ARMD).
Single centre orthopaedic unit.
Following the identification of complications potentially related to metal wear debris, a bloodmetalion screening programme was instigated at our unit in 2007 for all patients with Articular Surface Replacement (ASR) and Birmingham MoMhipresurfacings. Patients were followed annually unless symptoms presented earlier. Symptomatic patients were investigated with ultrasound scan and joint aspiration. The clinical course of all 278 patients with 'no pain' or 'slight/occasional' pain and a Harris Hip Score greater than or equal to 95 at the time of venesection were documented. A retrospective analysis was subsequently conducted using mixed effect modelling to investigate the temporal pattern of blood Co levels in the patients and survival analysis to investigate the potential role of case demographics and blood Co levels as risk factors for subsequent failure secondary to ARMD.
Blood Co concentration was a positive and significant risk factor (z=8.44, p=2×10(-16)) for joint failure, as was the device, where the Birmingham Hip Resurfacing posed a significantly reduced risk for revision by 89% (z=-3.445, p=0.00005 (95% CI on risk 62 to 97)). Analysis using Cox-proportional hazards models indicated that men had a 66% lower risk of joint failure than women (z=-2.29419, p=0.0218, (95% CI on risk reduction 23 to 89)).
The results suggest that elevatedbloodmetalionconcentrations are associated with early failure of MoM devices secondary to adverse reactions to metal debris. Co concentrations greater than 20 µg/l are frequently associated with metal staining of tissues and the development of osteolysis. Development of soft tissue damage appears to be more complex with females and patients with ASR devices seemingly more at risk when exposed to equivalent doses of metal debris.