The purpose of this study is to determine whether a computer navigational unit can improve operating time and consistency during Knee arthroplasty when compared to knee arthroplasty without a computer navigational unit.

The ability to use a computerized navigational unit during knee arthroplasty can be a major benefit to surgeons that perform a small amount of knee arthroplasties. Navigational assistance can decrease surgery and anesthesia time as well as decreasing variation in posterior tibial slope and improved range of motion.

Inclusion Criteria for the Oxford Knee

• symptomatic unicompartmental knee arthritis major surgery
• failed non operative treatment modalities
• willing and able to give informed consent
• skeletal maturity

Exclusion criteria for the Oxford Knee

• medical conditions that preclude general or spinal anesthetic
• ipsilateral knee avascular necrosis
• severe osteoporosis or osteopenia
• neuromuscular impairment
• ipsilateral knee infection

Patient day surgery criteria

• medically stable: an ASA category of 1 or 2
• close proximity to the hospital surgery performed for at least 36 hours
• good support system in place- someone able to stay with the patient for at least 36 hours immediately post-op.
• hemovac to be removed prior to discharge
• access to VON or other home care hospital approved services
• pain buster for pain control for 24 to 36 hours