Interpretation Modern second-generation uncemented stems, with proximal circumferential porous-or HA-coating, seem to be a good choice for young patients with primary OA. Similarly, modern press-fit porous-and HA-coated cups appear to have good endurance against aseptic loosening in these young patients. However, liner revisions were common; thus, survival rates of uncemented cups were unsatisfactorily low. Polyethylene wear and unfavorable locking mechanisms between the metal shell and the polyethylene liner and their sequelae remain matters of concern in this young and active group of patients.