Prospective, In-Vivo, Post-Market Safety and Efficacy Surveillance Registry of the MAXX Orthopedics, Freedom Total Knee® System

Revision / re-operation post-operatively due to device / device composite failure. An anticipated benefit of the device is that it is more conforming at higher degrees of flexion, which could potentially result in reduced polyethylene wear and improved survivorship over the longer-term. To assess this aspect of the device in addition to safety over the short-, intermediate- and long-term, survivorship analyses will be conducted at the targeted follow-up landmark timepoints.

There will be 3 survivorship endpoints:

• Revision of any component (including insert) for any reason
• Revision of any component (including insert) for any reason except infection

The Knee Society Score rating system was first introduced during the late 1980's and has become the standard clinical evaluation system for reporting results for patients undergoing Total Knee Arthroplasty. Most major journals strongly encourage that total knee manuscripts include Knee Society Score rating scores as part of the result section. The Knee Society Score consists of points given for pain, range of motion, and stability. The Function Score consists of points given for the ability to walk on level surfaces, and the ability to ascend and descend stairs, with deductions for the use of external supporting devices.

The KOOS-JR is self-administered and assesses three domains: stiffness (1 question), pain (4 questions), function / daily living (2 questions). The KOOS-JR meets basic criteria of outcome measures and can be used to evaluate the course of knee injury and treatment outcome. Each item (questions) is coded from 0 to 4. The raw responses are summed (0-28) which is then converted to an interval score based on the KOOS-JR conversion table. The score is a percentage score from 0 to 100, 0 representing total knee disability and 100 representing perfect knee health.

The Patient Reported Outcomes Measurement Information System (PROMIS Global-10) is a valid and reliable patient assessment and consists of ten (10) items that measure physical health, physical functioning, general mental health, emotional distress, satisfaction with social activities and relationships, ability to carry out usual social activities and roles, pain, fatigue and overall quality of life. The response options are presented as 5-point (as well as a single 11-point) rating scales. The results of the questions are used to calculate two summary scores: a Global Physical Health Score and a Global Mental Health score. These scores are then standardized to the general population, using the "T-Score". The average "T-Score" for the United States population is 50 points, with a standard deviation of 10 points. Higher scores indicate a healthier patient. The PROMIS 10 scores are predictive of healthcare utilization, mortality in general and disease-specific clinical populations.

This scale has been designed to give subjective pain information as to the degree of knee pain you the patient is currently experiencing. VAS scoring is included in the PROMIS GLOBAL-10 assessment and is not necessary to collect a separate assessment. Applying the VAS, the patient will select a number from 1 (no pain) to 10 (maximum pain) that most closely describes their current pain.

The 12 question Forgotten Joint Score (FJS-12) was introduced with the aim of assessing the patients 'joint awareness'. The authors of the score suggest the "higher the score" is more representative of higher-level function after surgery, as to be able to forget about the joint requires the absence of pain and the ability to perform all desired functional tasks without limitation.

• Evidence of correct component position
• Evidence of stable component fixation
• Review of incidence and location of any lucencies, sclerotic lines, component subsidence and/or osteolysis

• Local (wound and skin)
• Systemic (infection markers)
• Clinical / radiographic evidence of component / composite failure
• Unscheduled re-visit or re-operation within 24 months post-operatively.