PFC Sigma Fixed and Mobile Knee Study

Study Overview
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Brief Summary
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The primary objective of this investigation is to evaluate the performance (in terms of post-operative active range of motion at one year) of the P.F.C. Sigma and P.F.C. Sigma Rotating Platform total knee systems in clinical practice.

Detailed Description
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The secondary objectives of this investigation are:To evaluate the performance of the P.F.C. Sigma and P.F.C. Sigma Rotating Platform total knee systems in clinical practice. To evaluate the impact of patellar resurfacing on the performance of the P.F.C. Sigma and the P.F.C. Sigma Rotating Platform total knee systems. To evaluate the impact of Posterior Cruciate Ligament (PCL) sacrifice or retention on the performance of the P.F.C. Sigma and the P.F.C. Sigma Rotating Platform total knee systems.

Official Title
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Clinical Evaluation of the P.F.C. Sigma (Fixed Bearing) and P.F.C. Sigma RP (Mobile Bearing) Total Knee Systems

Conditions
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Osteoarthritis, Knee

Intervention / Treatment
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* Device: P.F.C Sigma Fixed Bearing total knee system
* Device: P.F.C Sigma RP Mobile Bearing knee system


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female subjects may be recruited to the evaluation. Age - there are no restrictions relating to age of the patient. The patient's age must be considered suitable by the clinical investigator for a bi-compartmental or tri-compartmental knee arthroplasty using either of the two systems available in the evaluation. Subjects who are able to give voluntary, written informed consent to participate in this investigation and from whom consent has been obtained. Subjects who, in the opinion of the Investigator, are able to understand this 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 require a bi-compartmental or tri-compartmental knee arthroplasty for primary surgical management of idiopathic osteoarthritis. Patients who in the opinion of the Clinical Investigator are considered to be suitable for treatment with a fixed or mobile bearing knee system and who are suitable for patella resurfacing. Exclusion Criteria: Patients who, in the opinion of the Investigator, have an existing condition that would compromise their participation and follow-up in this study. Patients who require revision total knee arthroplasty surgery. Patients with any tibial deformity requiring tibial component augmentation. Patients whom, in the opinion of the Clinical Investigator, require a constrained prosthesis. Patients with Rheumatoid Arthritis. Patients with a pathology which, in the opinion of the Clinical Investigator, will adversely affect healing. Patients with other disorders which, in the opinion of the Clinical Investigator, will / could impair rehabilitation. Contra-indications for use of the device, as detailed in the package insert. Women who are pregnant. Subjects who are known drug or alcohol abusers or with psychological disorders that could effect follow-up care or treatment outcomes. Subjects who are currently involved in another clinical study with an investigational product. Subjects who are currently involved in any injury litigation claims.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: PFC Sigma Fixed Bearing PCL Sacrificed<br>PFC Sigma Fixed Bearing Total Knee System with PCL Sacrificed | Device: P.F.C Sigma Fixed Bearing total knee system<br>* Orthopaedic implant for total knee replacement<br>|
| Active Comparator: PFC Sigma RP PCL Sacrificed<br>PFC Sigma Rotating Platform Total Knee System with PCL Sacrificed | Device: P.F.C Sigma RP Mobile Bearing knee system<br>* Orthopaedic implant for total knee replacement<br>|
| Other: PFC Sigma Fixed Bearing PCL Retained<br>PFC Sigma Fixed Bearing Total Knee System with PCL Retained | Device: P.F.C Sigma Fixed Bearing total knee system<br>* Orthopaedic implant for total knee replacement<br>|
| Active Comparator: PFC Sigma RP PCL Retained<br>PFC Sigma Rotating Platform Total Knee System with PCL Retained | Device: P.F.C Sigma RP Mobile Bearing knee system<br>* Orthopaedic implant for total knee replacement<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To Compare Range of Motion Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | 1 year | 
| To Compare Range of Motion Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | 1 year | 
| To Compare the Change in Range of Motion From Pre-op to 1 Year Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | Change from pre-op to 1 year | 
| To Compare the Change in Range of Motion From Pre-op to 1 Year Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | Change from pre-op to 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To Compare the Change in Range of Motion From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | Change from pre-op to 2 years | 
| To Compare the Change in Range of Motion From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | Change from pre-op to 2 years | 
| To Compare the Change in Range of Motion From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Range of motion is knee flexion (how far the patient can bend their knee) minus knee extension (how far the patient can straighten their knee). The result of this subtraction is the range of motion (bending and straightening) for that knee. | Change from pre-op to 5 years | 
| To Compare the Change in Oxford Knee Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | The Oxford Knee Score (OKS) is a 12 to 60 point patient reported outcome (PRO) score (where 12 indicates the best outcome) that evaluates the affected knee. The total score is composed of Pain and Function. | Change from pre-op to 2 years | 
| To Compare the Change in Oxford Knee Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The Oxford Knee Score (OKS) is a 12 to 60 point patient reported outcome (PRO) score (where 12 indicates the best outcome) that evaluates the affected knee. The total score is composed of Pain and Function. | Change from pre-op to 2 years | 
| To Compare the Change in Oxford Knee Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The Oxford Knee Score (OKS) is a 12 to 60 point patient reported outcome (PRO) score (where 12 indicates the best outcome) that evaluates the affected knee. The total score is composed of Pain and Function. | Change from pre-op to 5 years | 
| To Compare the Change in American Knee Society Knee Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | American Knee Society (AKS) knee score is a 0-100 point score (where 100 indicates excellent knee condition) that evaluates the affected knee. The knee score is composed of Pain, Range of Motion, and Stability. | Change from pre-op to 2 years | 
| To Compare the Change in American Knee Society Knee Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | American Knee Society (AKS) knee score is a 0-100 point score (where 100 indicates excellent knee condition) that evaluates the affected knee. The knee score is composed of Pain, Range of Motion, and Stability. | Change from pre-op to 2 years | 
| To Compare the Change in American Knee Society Knee Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | American Knee Society (AKS) knee score is a 0-100 point score (where 100 indicates excellent knee condition) that evaluates the affected knee. The knee score is composed of Pain, Range of Motion, and Stability. | Change from pre-op to 5 years | 
| To Compare the Change in American Knee Society Function Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | American Knee Society (AKS) function score is a 0-100 point score (where 100 indicates excellent knee function) that evaluates the affected knee. The function score is composed of walking and stair climbing ability. | Change from pre-op to 2 years | 
| To Compare the Change in American Knee Society Function Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | American Knee Society (AKS) function score is a 0-100 point score (where 100 indicates excellent knee function) that evaluates the affected knee. The function score is composed of walking and stair climbing ability. | Change from pre-op to 2 years | 
| To Compare the Change in American Knee Society Function Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | American Knee Society (AKS) function score is a 0-100 point score (where 100 indicates excellent knee function) that evaluates the affected knee. The function score is composed of walking and stair climbing ability. | Change from pre-op to 5 years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 2 years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 2 years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 5 Years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 2 years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 2 years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 5 Years | 
| To Compare the Change in SF-12 Physical Health Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The 12-Item Short Form Health Survey (SF-12) is a patient reported outcome survey that represents overall subjective health status by measuring eight health-related parameters (each scored from 0 [poor health] to 100 [better health]): body pain, general mental health, perception of general health, physical functioning, role limitations caused by mental condition, role limitations caused by a physical condition, social functioning, and vitality. The survey is converted into 2 summary measures that are scored from 0 to 100 (where 100 indicates the highest level of health) - the Physical Component Score (PCS-12) and Mental Component Score (MCS-12). | Change from pre-op to 2 years | 
| To Compare the Change in SF-12 Physical Health Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | The 12-Item Short Form Health Survey (SF-12) is a patient reported outcome survey that represents overall subjective health status by measuring eight health-related parameters (each scored from 0 [poor health] to 100 [better health]): body pain, general mental health, perception of general health, physical functioning, role limitations caused by mental condition, role limitations caused by a physical condition, social functioning, and vitality. The survey is converted into 2 summary measures that are scored from 0 to 100 (where 100 indicates the highest level of health) - the Physical Component Score (PCS-12) and Mental Component Score (MCS-12). | Change from pre-op to 2 years | 
| To Compare the Change in SF-12 Physical Health Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The 12-Item Short Form Health Survey (SF-12) is a patient reported outcome survey that represents overall subjective health status by measuring eight health-related parameters (each scored from 0 [poor health] to 100 [better health]): body pain, general mental health, perception of general health, physical functioning, role limitations caused by mental condition, role limitations caused by a physical condition, social functioning, and vitality. The survey is converted into 2 summary measures that are scored from 0 to 100 (where 100 indicates the highest level of health) - the Physical Component Score (PCS-12) and Mental Component Score (MCS-12). | Change from pre-op to 5 years | 
| To Compare the Change in SF-12 Mental Health Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The 12-Item Short Form Health Survey (SF-12) is a patient reported outcome survey that represents overall subjective health status by measuring eight health-related parameters (each scored from 0 [poor health] to 100 [better health]): body pain, general mental health, perception of general health, physical functioning, role limitations caused by mental condition, role limitations caused by a physical condition, social functioning, and vitality. The survey is converted into 2 summary measures that are scored from 0 to 100 (where 100 indicates the highest level of health) - the Physical Component Score (PCS-12) and Mental Component Score (MCS-12). | Change from pre-op to 2 years | 
| To Compare the Change in SF-12 Mental Health Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | The 12-Item Short Form Health Survey (SF-12) is a patient reported outcome survey that represents overall subjective health status by measuring eight health-related parameters (each scored from 0 [poor health] to 100 [better health]): body pain, general mental health, perception of general health, physical functioning, role limitations caused by mental condition, role limitations caused by a physical condition, social functioning, and vitality. The survey is converted into 2 summary measures that are scored from 0 to 100 (where 100 indicates the highest level of health) - the Physical Component Score (PCS-12) and Mental Component Score (MCS-12). | Change from pre-op to 2 years | 
| To Compare the Change in SF-12 Mental Health Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The 12-Item Short Form Health Survey (SF-12) is a patient reported outcome survey that represents overall subjective health status by measuring eight health-related parameters (each scored from 0 [poor health] to 100 [better health]): body pain, general mental health, perception of general health, physical functioning, role limitations caused by mental condition, role limitations caused by a physical condition, social functioning, and vitality. The survey is converted into 2 summary measures that are scored from 0 to 100 (where 100 indicates the highest level of health) - the Physical Component Score (PCS-12) and Mental Component Score (MCS-12). | Change from pre-op to 5 years | 
| To Compare the Change in Patella Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 2 years | 
| To Compare the Change in Patella Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 2 years | 
| To Compare the Change in Patella Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 5 years | 
| To Compare the Percentage of Subjects With at Least 1 Tibial Radiolucency Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Tibial Radiolucency observes a radiolucent line (of 0.5mm or wider) on the radiograph around the tibial component. | 2 years | 
| To Compare the Percentage of Subjects With at Least 1 Tibial Radiolucency Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Tibial Radiolucency observes a radiolucent line (of 0.5mm or wider) on the radiograph around the tibial component. | 2 years | 
| To Compare the Percentage of Subjects With at Least 1 Tibial Radiolucency Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Tibial Radiolucency observes a radiolucent line (of 0.5mm or wider) on the radiograph around the tibial component. | 5 Years | 
| To Compare the Percentage of Subjects With Lateral Release Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Lateral release is a surgical procedure to release tight capsular structures (lateral retinaculum) on the outside of the kneecap (patella). It is performed during knee surgery and allows the kneecap to move smoothly in the center of the knee. Rate information was collected at time of study surgery. | Operative | 
| To Compare the Percentage of Subjects With Lateral Release Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Lateral release is a surgical procedure to release tight capsular structures (lateral retinaculum) on the outside of the kneecap (patella). It is performed during knee surgery and allows the kneecap to move smoothly in the center of the knee. Rate information was collected at time of study surgery. | Operative | 
| To Compare the Survivorship Analysis Results Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Kaplan Meier survivorship analysis estimates the proportion of a population that will survive past a certain time avoiding a certain event. In this study, the event is removal of any component for any reason, also known as revision for any reason. Survival estimates are provided when 40 devices are left still being followed. | 2 Years | 
| To Compare the Survivorship Analysis Results Between Sigma RP and Sigma Fixed Treatment Groups in PCL Retaining Arm | Kaplan Meier survivorship analysis estimates the proportion of a population that will survive past a certain time avoiding a certain event. In this study, the event is removal of any component for any reason, also known as revision for any reason. Survival estimates are provided when 40 devices are left still being followed. | 2 Years | 
| To Compare the Survivorship Analysis Results Between Sigma RP and Sigma Fixed Treatment Groups in PCL Sacrificing Arm | Kaplan Meier survivorship analysis estimates the proportion of a population that will survive past a certain time avoiding a certain event. In this study, the event is removal of any component for any reason, also known as revision for any reason. Survival estimates are provided when 40 devices are left still being followed. | 5 Years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Bearing Treatment Groups With Patella Resurfacing in the PCL Sacrificing Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 2 Years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Bearing Treatment Groups Without Patella Resurfacing in the PCL Sacrificing Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 2 Years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Bearing Treatment Groups With Patella Resurfacing in the PCL Sacrificing Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 5 Years | 
| To Compare the Percentage of Subjects With No Anterior Knee Pain Between Sigma RP and Sigma Fixed Bearing Treatment Groups Without Patella Resurfacing in the PCL Sacrificing Arm | Anterior Knee Pain is assessed by the patient into 1 of 4 categories: None, Mild, Moderate, or Severe. The percentage of participants with no anterior knee pain is reported in the data table. | 5 Years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Bearing Treatment Groups With Patella Resurfacing in the PCL Sacrificing Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 2 Years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Bearing Treatment Groups Without Patella Resurfacing in the PCL Sacrificing Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 2 Years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Bearing Treatment Groups With Patella Resurfacing in the PCL Sacrificing Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 5 Years | 
| To Compare the Percentage of Subjects With Good Quadriceps Strength Between Sigma RP and Sigma Fixed Bearing Treatment Groups Without Patella Resurfacing in the PCL Sacrificing Arm | Quadriceps Strength is assessed by the patient into 1 of 3 categories: Good, Fair, or Poor. The percentage of participants with good quadriceps strength is reported in the data table. | 5 Years | 
| To Compare the Change in Patella Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Bearing Treatment Groups With Patella Resurfacing in the PCL Sacrificing Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 2 years | 
| To Compare the Change in Patella Score From Pre-op to 2 Years Between Sigma RP and Sigma Fixed Bearing Treatment Groups Without Patella Resurfacing in the PCL Sacrificing Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 2 years | 
| To Compare the Change in Patella Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Bearing Treatment Groups With Patella Resurfacing in the PCL Sacrificing Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 5 years | 
| To Compare the Change in Patella Score From Pre-op to 5 Years Between Sigma RP and Sigma Fixed Bearing Treatment Groups Without Patella Resurfacing in the PCL Sacrificing Arm | The Patella Score is completed by the clinicians and assesses the anterior knee pain, quadriceps strength, ability to rise from a chair and stair climbing. The Patella Score ranges from 3 to 30 points with higher scores indicating better functionality and lower scores indicating poorer functionality. | Change from pre-op to 5 years |