The purpose of the study is the evaluation of the clinical and radiological long-term performance of the balanSys UNI fix in a multicenter routine clinical setting.

Prospective multicenter follow-up study which examines the short- to long-term post-market clinical data on the safety and performance of the balanSys UNI fix knee prosthesis.

In total at least 100 participants in 3 clinics are included in this multicenter study.

The primary endpoint of the study is the Knee Society Score (KSS) 2 years after surgery.

The following parameters will be collected during the regular clinical and radiological follow-up: Knee Society Score, Knee and Osteoarthritis Outcome Score (KOOS), radiographic evaluation and detection of adverse events.

Inclusion Criteria:

• Informed consent form (signed by participant and investigator)
• Primary implantation
• Age at inclusion: Between 18 and 90 years old
• Willing to participate in the follow-up

Exclusion Criteria:

• Missing Informed consent form
• Known or suspected non-compliance (e.g. drug or alcohol abuse)
• Enrollment of the investigator, his/her family, employees and other dependent persons
• Patient younger than 18 years old
• Revision surgery
• Does have a known allergy to metal in medical devices
• Suffers from ACL rupture
• Pregnancy or in the breast feeding period

according to Eligibility Criteria