Hip replacements are typically a common form of surgery, particularly in older patients with a history of severe arthritis or degradation of the bones in the hip area. Patients with hip replacements could be affected hip replacement recalls and not realize that they are part of the class action lawsuit. In 1998, two implants were recalled, Stryker Trident implants and zirconia ceramic femoral head manufactured by St. Gobain Desmarquest and distributed to over 51 companies in the U.S. The Stryker Trident recall affects two implants, the Trident Acetabular PSL Cup and the Trident Hemispherical Cup, both used in the socket of the hip replacement. The PSL is one of the most common hip replacement versions used in the U.S. Deviations from manufacturer's specifications were found, which necessitated the recall. The ceramic femoral head was recalled due to the manufacturer changing a part of its process that left the ceramic more fragile. The recall was initiated after a high rate of fractures occurred 13 to 27 months post-op. Patients with hip replacements often do not know the brand name of the parts used during the replacement and should seek the advice of an attorney specializing in hip replacement recalls.