• To determine whether mechanical axis of the limb malalignment differs between patients whom have computer-assisted TKA and those treated with conventional intraoperative instrumentation
  

• To compare the frontal alignment of the femoral and tibial components from full length standing radiographs
  
• To compare sagittal alignment of the femoral and tibial components from lateral radiographs
  
• To compare the rotation of the femoral and tibial components from CT Scan.
  

Primary data to be obtained is to determine whether mechanical axis of the limb malignment differs between patients whom have computer-assisted TKA and those treated with conventional intraoperative instrumentation.

Three months after surgery follow-up radiographic data will provide evidence on the initial implant position as determined with a series of x-rays including: full length standing, standard AP weight bearing, lateral, patellar, kneelingfilm views and CT evaluation. In addition, a correlation betweeen the CT measures and the kneeling x-ray can be performed at this time. Clinical (Knee Scale Society, WOMAC, and SF-36) data will also be obtained at the three month interval.

Study participants must:

1. Be over 18 years of age.
2. Require a TKA and is considered by the investigator to be a suitable candidate for the specific knee prosthesis identified in protocol.
3. The subject has given consent to the transfer of his/her information to the sponsor.