Inclusion Criteria:

• Male or female subjects, aged between 45 and 75 years inclusive.
• Subjects who are able to give voluntary, written informed consent to participate in this clinical investigation and from whom consent has been obtained.
• Subjects who, in the opinion of the Clinical Investigator, are able to understand this clinical investigation, co-operate with the investigational procedures and are willing to return to the hospital for all the required post-operative follow-ups.
• Subjects who present with osteoarthritis that in the opinion of the clinical investigator requires a primary total knee arthroplasty.
• Subjects who in the opinion of the Clinical Investigator are considered to be suitable for treatment with either the P.F.C Sigma RP-F or the P.F.C Sigma RP knee, according to the indications specified in the package insert leaflet.
• Subjects who have authorised the transfer of his/her pseudonymised information to DePuy.

Exclusion Criteria:

• Subjects who, in the opinion of the Clinical Investigator, have an existing condition that would compromise their participation and follow-up in this clinical investigation.
• Female subjects who are pregnant or lactating.
• Subjects who are known drug or alcohol abusers or with psychological disorders that could affect follow-up care or treatment outcomes.
• Subjects who have participated in a clinical investigation with an investigational product in the last month( 30 days).
• Subjects who are currently involved in any injury litigation claims.
• Subjects with a known history of poor compliance to medical treatment.
• Subjects who have previously had an osteotomy or significant surgery in the affected knee.