Cobalt-chrome modular neck hip replacements: risk of metal-wear effects and revision surgery (DSI/2026/010)

We use some essential cookies to make this website work. We’d like to set additional cookies to understand how you use GOV.UK, remember your settings and improve government services. We also use cookies set by other sites to help us deliver content from their services. You have accepted additional cookies. You can change your cookie settings at any time. You have rejected additional cookies. You can change your cookie settings at any time. An MHRA investigation has found increased risks of wear and corrosion associated with multiple cobalt-chrome (Co-Cr) modular neck hip stem components, including a potential increased occurrence of revision surgery due to adverse local tissue reaction (ALTR). An MHRA investigation has found increased risks of wear and corrosion associated with multiple cobalt-chrome (Co-Cr) modular neck hip stem components, including a potential increased occurrence of revision surgery due to adverse local tissue reaction (ALTR). There is a potential increased risk of wear and corrosion associated with the presence of two interfaces on the dual taper modular neck: one between the modular neck and the modular hip stem, and another between the modular neck and modular head. MHRA recommends that patients implanted with affected devices should be invited for a virtual or face-to-face clinical review to inform them of the potential risks, assess their clinical presentation and discuss the need for continued follow-up. Two of the systems in scope of this DSI (ABG II modular and SMF) have already been the subject of previous investigations by the manufacturers. Patients implanted with these devices may not need further follow-up if they are already undergoing monitoring based on the manufacturers’ previous recommendations. Clinical follow-up recommendation: perform a whole blood test for cobalt and chromium* using a laboratory associated with one of the following schemes: each patient should be assessed on an individual basis consider revision surgery if any of the following are present: following this clinical review: *there is no agreed threshold value for whole blood metal levels that either predicts outcome, or mandates revision. Decisions to revise are influenced by patient factors, blood metal levels, imaging findings, and implant type and position. Other patient specific factors may need to be considered when interpreting results for blood metal levels. This investigation followed on from the investigation detailed in DSI/2025/005 which found increased risks of wear and corrosion associated with the Profemur cobalt-chrome modular neck hip system, including an increased occurrence of device fracture and revision surgery. This investigation examined all other hip replacements with a cobalt-chrome modular neck that have ever been available on the UK market. These devices were all removed from the market prior to 2019 and none remain commercially available. Cobalt-chrome dual taper modular neck hip replacements were introduced to the market with the intention of allowing better alignment of hip stems to the anatomy of the patient and restoring more natural biomechanics compared to non-modular systems, due to the option for intraoperative decision making. The potential benefits of this design have been considered alongside the potential increased risk of wear and corrosion associated with the presence of two interfaces: one between the modular neck and the modular hip stem, and another between the modular neck and modular head. The individual benefits and risks of each device were also considered, given the differences in device design, indications, stated benefits, population of use, number of implants used and available data. The investigation found that the rate of revision due to metal-related effects (such as ALTR) varied between different implant systems. Table 1 shows a breakdown of usage and outcomes for these devices based on data from the UK National Joint Registry (NJR) extracted in June 2026. ‘Material