NexGen TM Tibia Clinical Outcomes Study

This is a prospective, multicenter, non-randomized clinical study designed to facilitate the collection and evaluation of radiographic parameters, pain and function, survival of the device, and adverse event data. This clinical study will include the NexGen TM Monoblock Tibia and NexGen TM Modular Tibia as 2 single-arms being analyzed separately. The study will require each site to obtain IRB approval prior to study enrollment. All potential study subjects will be required to participate in the Informed Consent Process. All study subjects will undergo preoperative clinical evaluations prior to their cementless tibia total knee arthroplasty. An immediate postoperative radiograph will be required. Postoperative clinical follow-up and radiographic evaluations will be conducted at 6 weeks, 6 months, 1 year, and 2 years. The primary endpoint of this study is to evaluate the clinical performance of the implant at 2 years postoperatively using radiographic parameters. Radiographs will be assessed for the absence of progressive tibial radiolucencies, as defined in the radiographic protocol. The secondary endpoints of this study will evaluate the clinical performance of the implant at 2 years postoperatively, based upon: * No revisions for any reason * Oxford Knee Score \>38