The results obtained 1 year after surgery were clearly indicative of the outcome and the investigators decided to terminate follow-up at that point.

Overall study design:

A prospective, randomized, multi-center clinical studies comparing the minimal invasive and the standard surgical total knee replacement technique (control) using the Genesis II total knee system. The study will collect efficacy, safety and socio-economical data over 2 years. An additional 5 years follow-up interval is optional. The objectives (short-term follow-up) of the study are to:

1. Assess whether the improvement in Pain and Range of motion per Knee Society scoring system and VAS score.
2. Assess whether there are any differences between the surgical techniques as regards complication rate.
3. Assess whether the hospital stay and the rehabilitation time (Straight leg raise, Active/passive ROM) of the patients differs between the two techniques.
4. Assess the x-ray mechanical alignment between the two techniques.

Attempts will be made to assess whether the collected peri-operative data (including incision length, blood loss, wound appearance, hospital readmissions and operative time) differs between the two surgical techniques.

The primary objectives (mid-term follow-up) of the study are to:

1. Improvement in Pain and Function per Knee Society Scoring system
2. Number and Extent of Radiographic Lucencies >2mm
3. Revision and knee-related adverse events
4. Improvement in Quality-of-life via the VAS score

5 investigational sites will participate and enroll a total of approximately 250 patients over a 12 months period. Thus, each site will enroll 50 patients.

Inclusion Criteria:

• require primary uni- or bilateral total knee arthroplasty; available for 2 year follow up; provide informed consent; is in stable health for cardio-pulmonary conditions.

Exclusion Criteria:

• inefficient femoral or tibial bone stock; BMI >35; fixed flexion deformity >15 degrees; knee flexion of <90 degrees; varus/valgus deformity >20 degrees; active local infection; conditions that would compromise the 2 years follow up.