Study had to be terminated before first patient got enrolled due to insufficient case number.

The study is a single-center, retrospective and prospective, non-randomized, non-controlled and consecutive series post-market study. The purpose of this study is to confirm safety, performance and clinical benefits of the NexGen TM Augmentation Patella. The primary objective is the assessment of safety by analyzing implant survivorship. This will be established by recording the incidence and frequency of revisions, complications and adverse events. Relation of the events to implant, instrumentation and/or procedure should be specified.

The secondary objective is the assessment of performance and clinical benefits by recording patient-reported clinical outcome measures (PROMs) as well as radiographic outcomes.

The Nexgen TM Augmentation Patella is intended to help compensate for significant bone loss in the patella during revision total knee arthroplasty.

One site will be involved in this study. The aim is to include a total of 25 consecutive series patients who received the NexGen TM Augmentation Patella starting from 2014 at the Inselspital Bern. All potential study subjects will be required to participate in the Informed Consent Process.

Baseline data from the preop, intraop and immediate post-op intervals will be available in medical notes and collected retrospectively. During follow-up visits at 1, 3, 5, 7 and 10 years post-op (depending on patients' date of surgery), the patient will be asked to complete patient questionnaires. Moreover, a clinical assessment and a radiographic evaluation will be conducted. In addition, any complications and adverse events will also be collected during these follow-up visits.

Inclusion Criteria:

• Non-inflammatory degenerative joint disease including osteoarthritis or traumatic arthritis
• Rheumatoid arthritis
• Correction of functional deformity
• Revision procedures where other treatments or devices have failed
• Treatment of fractures that are unmanageable using other techniques
• Complication from a failed prosthesis
• For cementless use only
• Supplemental fixation, when required, must be achieved by means of suture attachment.

Exclusion Criteria:

• Off-label use
• Primary arthroplasty
• Overt Infection
• Distant foci of infection (which may spread hematogenously to the implant site)
• Rapid disease progression as manifested by joint destruction or bone resorption apparent on roentgenogram
• Skeletally immature patients
• Cases where there is inadequate bone stock or no bone stock which would make the procedure unjustifiable
• Patients who are not willing to return for study required follow-up visits and/or are not willing to comply with the follow-up schedule
• Patient who is a vulnerable subject (prisoner, mentally incompetent or unable to understand what participation to the study entails, a known alcohol or drug abuser, anticipated to be non-compliant, younger than 18 years)

The study population will be comprised of a consecutive series of patients who have been operated with the NexGen TM Augmentation Patella according to Zimmer Biomet's Instruction for Use (IFU) and who meet the inclusion criteria and none of the exclusion criteria.