Operative Procedures The mini-subvastus approach and the medial parapatellar approach are the two surgical approaches that will be studied with respect to gait analysis, activity level and thigh strength. A cemented condylar implant, FDA approved devices, will be used for all cases in this study. The only difference between the two treatment groups will be the surgical approach for inserting these components. These two surgical approaches comprise the two study arms and are described in detail below.