The study will evaluate the performance, clinical benefits and safety of the Persona Revision Knee System in patients who have received primary or revision total knee arthroplasty (TKA) treatment. This will be done using a multicenter, single-arm, consecutive series, retrospective cohort study with prospective follow-up.

Under study are the Persona® Revision Knee System (K181947 and K191625) implants and instrumentation, and any compatible devices being used in conjunction according to the Instructions for Use. This will be accomplished by retrospectively identifying patients who underwent primary or revision TKA with this system and inviting them to participate in prospective data collection at 1, 2, 3, 4, 5, 7, and 10 years postoperative follow-up. As the device was not available for commercial use until late 2019, the retrospective portion will involve those activities that occurred per standard of care for participants.

The primary endpoint for this study will be performance assessed by improvement in the 1989 Knee Society Clinical Rating System (KS) objective knee score (KS-KS) from baseline to 2 years (as evaluated using the overall group mean showing at least the Minimal Clinically Important Difference (MCID) of 5.4 points).

A maximum of 20 sites will contribute to this study. There will be a maximum of 380 patients enrolled in the study.

Inclusion Criteria:

1. Male or female of at least 18 years of age at the time of screening.

2. Signed an institutional review board approved informed consent.

3. Willingness and ability to comply with the study procedures and visit schedules and ability to understand and follow oral and written post-operative care instructions.

4. Previous medical diagnosis/ history of at least one of the following conditions requiring treatment using the Persona Revision Knee System within a pre-specified study variant configuration (cohort), in accordance with the instructions for use (IFU):

   1. Rheumatoid arthritis, osteoarthritis, traumatic arthritis or polyarthritis
   2. Collagen disorders, and/or avascular necrosis of the femoral condyle
   3. Post-traumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy
   4. Moderate valgus, varus, or flexion deformities
   5. The salvage of previously failed surgical attempts or for a knee in which satisfactory stability in flexion cannot be obtained at the time of surgery

5. A pre-operative Knee Society Knee Score (objective assessment) ≤ 80.

Exclusion Criteria:

1) Presence of clinically observed active or suspected latent infection in the affected joint at the time of procedure.

3) Presence of of local/systemic/distant focal infection that may affect or hematogenously spread to the prosthetic joint.

4) Skeletal immaturity or insufficient bone stock on femoral or tibial surfaces which cannot provide adequate support and/or fixation to the prosthesis.

5) Diagnosed with neuropathic arthropathy, osteoporosis, or any loss of musculature or neuromuscular disease that compromises the affected limb.

6) Presence of a stable, painless arthrodesis in a satisfactory functional position in the affected joint.

7) Severe instability of the affected joint secondary to the absence of collateral ligament integrity.

8) Diagnosis of rheumatoid arthritis in conjunction with any of the following at the time of screening:

1. An ulcer of the skin

2. History of recurrent breakdown of the skin

3. Use of steroids

   9) Patient requires simultaneous bilateral knee surgery for treatment of diagnosed condition.

   10) Pregnant or women planning to become pregnant during the time they will be participating in the study.

   11) Any documented clinically significant degree of cognitive impairment or other condition, finding, or psychiatric illness at screening which, in the opinion of the Investigator, could compromise patient safety or interfere with the assessment of the safety and treatment effects of the study procedure.

   12) Any patient who is institutionalized, or with a known drug or alcohol dependence currently or within the last year.

Patients in need of a primary or revision total knee procedure who receive Persona Revision Knee implants who meet all the inclusion criteria and none of the exclusion criteria.