Recently, concerns have been raised about the use of metal-on-metal (MoM) implants. This has led to the recall of several resurfacing and large-diameter total hip arthroplasties (THA). Any MoM interface can be the cause of metal debris and adverse tissue reactions. We analyzed serum metal ions and HOOS scores in 19 of 306 patients treated with a THA with modular neck section. The only MoM interface in this particular implant is the taper between the neck and the stem. The articulating surface consists of a ceramic-on-polyethylene or ceramic-on-ceramic interface. As such, this study looks at the metal ion production from the modular neck section. One of 306 implants needed revision at 52-month follow-up because of an adverse reaction to metal debris (ARMD).