Abstract
Introduction
The Medicines and Healthcare Products Regulatory Agency (MHRA) of the UK have published guidelines for annual follow up of patients with metal on metal hip replacements following widespread concern regarding metallosis
Methods
We followed up 718 total hip replacements (594 stemmed hips and 124 resurfacing) with metal on metal bearing, implanted between April 1999 and August 2010 in dedicated clinics with clinical and radiological assessment along with assessment of serum metal ions. Survival was calculated using Kaplan Meier analysis.
Results
Twenty two hips had already been revised at the start of recall. Mean follow up was 108 months (180 – 44). Forty four patients had deceased and forty seven were lost to follow up. Six percent of patients had high metal ion levels and radiological analysis showed that twenty two percent of cups were outside the Lewinnek's safe zone. Fifteen months into the recall process a total of forty one hips have been revised.
Discussion
Our revision rates are similar to that reported in literature thus far but this could increase. Instability arising due to the extensive soft tissue damage seen in such patients could become a major concern and arthroplasty units should be prepared to deal with this.
