Experience with Modular Necks for Cemented Total Hip Arthroplasty

This is a retrospective review of two series of using the same stem and modular neck design (R-120™) with the exception that the second series had an improved modular neck construct. Model I, 145 stems implanted between 2002 and 2005. Taper neck problems consisted of two neck trunion fractures at the neck stem junction and one modular neck disassociation at the modular junction. Stem was withdrawn from the market and redesigned to a more robust structure. Model II, 188 stems were implanted between 2007 and 2011 by the senior author utilizing the same surgical technique. There have been no modular neck taper problems. This paper will demonstrate that once a modular junction problem has been identified corrective action can be taken to resolve the problem. We advocate that there is a benefit to a modular neck cemented stem design and all modular junctions are not equal in design or function.