Merete brought the BioBall® System onto the market as a “modular joint prosthesis system” at the end of the 1990s. In the meantime, it has become the gold standard in revision hip arthroplasty surgery. The BioBall® Adapter, consisting of titanium alloy, allows intra-operative correction of neck length as well as antetorsion/retrotorsion and lateralisation/medialisation on in situ stems. This significantly improves the gait pattern and reduces the dislocation risk. With its offset components and special tapers, the system ought to be available in every hospital as a solution for unexpected situations in primary endoprosthetic care as well.When it comes to revision surgeries, the BioBall® System offers another unique feature: With stems left in situ with previously used tapers, the BioBall® Adapter compensates mild deformation of the taper surface. Depending on the specific model, BioBall® Adapters are available in sizes ranging from S - 5XL, as standard or offset versions, for 12/14 and 14/16 tapers. Custom adapters for additional tapers are available on request.