Postoperative Rehabilitation After Knee Arthroplasty: Anti-Gravity Treadmill

The study will include patients with grade III-IV primary knee osteoarthritis. The investigators will take 27 patients to the both groups. The investigators will look after more specifically the anti-gravity treadmill rehabilitation and traditional rehabilitation after arthroplasty. Follow-up is one year. Functional tests will be made and questionnaires will be given to the patients before operation and after operation. After 6 to 8 weeks, 4 months and 12 months of operation questionnaires will be fil up again. After six month the investigators will send a questionnaire and there will be asked possible rehabilitation sessions, use of drugs and possible complications after knee arthroplasty.