TY - JOUR T1 - Metal-on-metal hip replacements: implications for general practice JF - British Journal of General Practice JO - Br J Gen Pract SP - 544 LP - 545 DO - 10.3399/bjgp17X693557 VL - 67 IS - 665 AU - Victoria K Matharu AU - Gulraj S Matharu Y1 - 2017/12/01 UR - http://bjgp.org/content/67/665/544.abstract N2 - Hip replacements with large metal-on-metal bearing surfaces were introduced in the late 1990s. These devices aimed to improve outcomes in young and active patients with hip arthritis, who had experienced poor results with conventional implants. Metal-on-metal bearings showed early promise, with 1.5 million implanted worldwide as stemmed hip replacements and hip resurfacings (non-stemmed surface replacement). Unfortunately these devices experienced unexpectedly high short-term failure rates and have rarely been used since 2012.1 Furthermore, concerns have been raised about the potential long-term systemic effects of metal ions in the blood. High metal ion exposure poses a theoretical risk of developing certain cancers, while some deaths have been reported in metal-on-metal hip patients which occurred due to cardiac failure secondary to metal ion toxicity. However large cohort studies have presently observed that metal-on-metal hip patients are not at increased risk of cancer, heart failure, or mortality compared with other hip replacement patients.2Many metal-on-metal hips have required revision surgery for abnormal reactions to metal debris generated from the implant, which can substantially damage the bone and soft-tissues.1,3,4 These reactions can occur in patients with minimal or no symptoms, and outcomes following revision surgery were initially poor.4 It was thought that outcomes could be improved by identifying problems early. Therefore since 2012 worldwide regulators, such as the Medicines and Healthcare products Regulatory Agency (MHRA), have recommended screening many metal-on-metal hip patients,5 though this screening is extremely variable and very costly.6 In addition to clinical review (history and examination, including gait), metal-on-metal hip replacement patients can require blood metal ion testing (cobalt and chromium concentrations, which reflect implant wear), X-rays (to identify signs suggestive of implant failure), and ultrasound or magnetic resonance imaging (to identify soft-tissue disease, such as ‘pseudotumour’ masses4 and muscle damage). … ER -