The purpose of this study is to compare two different surgical approaches for total knee replacement surgery. The mini-midvastus approach involves cutting less of the thigh muscle (quadriceps) tendon than the classic approach (median parapatellar) in order to implant the knee components. Both will have the same skin incision.

Inclusion Criteria:

1. Patient is a male or non-pregnant female between the ages of 21-80.
2. Patient requires cemented primary total knee replacement.
3. Patient has a diagnosis of osteoarthritis (OA), traumatic arthritis (TA) or avascular necrosis (AVN).
4. Patient has intact collateral ligaments.
5. Patient has signed and dated an IRB approved study specific consent form.
6. Patient is able and willing to participate in the study according to the protocol for the full length of the expected term of follow-up, and to follow their physician's directions.
7. Patient has failed to respond to conservative treatment modalities.

Exclusion Criteria:

1. Patient has had a prior procedure of high tibial osteotomy, cruciate ligament reconstruction or patellectomy of the surgical knee.
2. Patient is morbidly obese, >60% over ideal body weight for frame and height.
3. Patient has a deformity at the involved knee greater than 45 degrees of flexion, 45 degrees of varus or 45 degrees of valgus.
4. Patient has an active or suspected latent infection in or about the knee joint.
5. Patient has a malignancy in the area of the involved knee joint.
6. Patient has a diagnosed systemic disease that would affect the subject's welfare or overall outcome of the study (i.e. moderate to severe osteoporosis, Paget's disease) or is immunologically suppressed, or receiving steroids in excess of physiologic dose requirements.
7. Patient has a neurological deficit, which interferes with the patient's ability to limit weight bearing or places an extreme load on the implant during the healing period.
8. Female patient is or plans to become pregnant during the course of the study.
9. Patient has a known sensitivity to device materials.
10. Patient has prior diagnosis of diabetic or peripheral neuropathy in operative extremity or other neurologic disease affecting limb strength
11. Patient's bone stock is compromised by disease or infection, which cannot provide adequate support and/or fixation to the prosthesis.

Forty consecutive patients who underwent staged bilateral Total Knee Arthroplasty were prospectively randomised to receive mini MedialParapatellar Approach in one knee and mini-midvastus approach in the other knee (left or right)within no more than 7 days.

The strength of the study is the standardized surgical protocol performed by a single surgeon and a prospectively randomized consecutive and blinded subjects