Open and Closed Platform Robotic-assisted Versus Conventional Total Knee Arthroplasty

Femoral Flexion Angle: The lateral view femoral flexion angle (X) is obtained from the intersection of a line from the center of the femoral implant to the top of the femur with a line through the femoral canal. The angle is measured on the proximal side of the intersection Tibial Lateral Angle: The lateral view tibial angle (Y) is the angle obtained from the intersection of a line drawn parallel to the bottom of the tibial base insert and a line through the center of the tibial base and the tibial canal.

The femoral prosthesis coronal alignment is the degree to which the femoral prosthesis is deviated from the mechanical axis of the lower extremity.

The femoral sagittal alignment gives the flexion of the femoral component in lateral view. The flexion of the component is the angle formed between the mechanical axis of the femur in the sagittal plane and the line perpendicular to the tangent of the distal portion of the femoral component.

The rotation of the femoral component is defined on the axial section of the post-operative CT scan. The angle of deviation between the radiographic trans-epicondylar axis (rTEA) and femoral prosthesis posterior condylar line (FPPCL) is the amount of femoral component rotation.

The tibial prosthesis coronal alignment gives the varus/valgus angulation of the prosthesis which affects the mechanical axis of the lower limb.

The tibial slope is calculated pre-operatively as the angle between the perpendicular to the anatomical axis of the tibia and the line joining the anterior and posterior point of the tibial surface on the lateral view.

In this study, the tip of the fibular head is used as the fixed bony point to calculate the joint line pre- and post-operatively. Pre-operatively, the perpendicular distance from the tip of the fibular head to the joint line of knee was termed as the joint line distance. Post-operatively, the perpendicular distance from the tip of the fibular head to the line joining the medial and lateral femoral prosthesis was termed as the joint line distance.

The KSS is a validated tool that combines an objective physician-derived component with a subjective subject-derived component. The KSS consists of 34 questions and provides sub-scores across 4 dimensions, including Objective Knee Score, Symptoms, Subject Satisfaction Score, Subject Expectation, and Functional Knee Score.

The Objective Knee Score is rated by the clinician and assesses a range of clinical outcomes: TKA alignment, stability, range of motion (ROM) and symptoms.

The KSS is an instrument assessing patient's pain and functionality based on a series of questions interviewed by a clinician. The validated questionnaire combines the objective physician derived component with a subjective patient derived component which evaluates pain, functionality, satisfaction and fulfillment of expectations. The results will be calculating the total score with 100 being the highest and 0 the lowest.

The OKS will be collected at the pre-operative visit and 6 weeks, 6 months, and 12 months after surgery.

The OKS is a Patient Reported Outcome (PRO) questionnaire that was developed to specifically assess the patient's perspective of outcome following Total Knee Arthroplasty. The OKS is a patient self-completion PRO containing 12 equally weighted questions on activities of daily living. The OKS has been developed and validated specifically to assess perceived function and pain answered on a Likert scale after TKA. Responses to each question ranges from 0-4 with a range of a possible overall score from 0-48. A score of 0 is the worst possible outcome while a score of 48 is the best possible outcome. The benefit to this questionnaire is that it is short, practical, reliable, valid and sensitive to clinically important changes over time.

A paper questionnaire will be provided by the Sponsor to be completed by the subject. Responses for the OKS will then be recorded.

The EQ-5D-5L essentially consists of 2 pages: the EQ-5D descriptive system and the EQ visual analogue scale (EQ VAS).

The descriptive system is used to describe the subject's health state and consists of five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has 5 levels to choose the most appropriate answer: no problems, slight problems, moderate problems, severe problems, and extreme problems. The subject is asked to indicate his/her health state by marking the most appropriate statement in each of the five areas.

Each dimension in the EQ-5D-5L has five response levels: no problems (Level 1); slight; moderate; severe; and extreme problems (Level 5). There are 3,125 possible health states defined by combining one level from each dimension, ranging from 11111 (full health) to 55555 (worst health)

The FJS will be collected at 6 weeks, 6 months, and 12 months after surgery. A paper questionnaire will be provided to be completed by the subject.

The FJS comprises measures for the assessment of joint-specific patient reported outcomes. This questionnaire focuses on the study subject's awareness of the partially or fully replaced knee joint in everyday life. Joint awareness can be simply defined as any unintended perception of a joint. Subjects are asked to rate their awareness of their knee arthroplasty in 12 questions with a five point Likert response format: "Never", "almost never", "seldom", "sometimes" and "mostly". The item scores are summed and linearly transformed in a 0 to 100 scale with a high value reflecting the ability of the subject to forget about the replaced knee joint during the activities of daily living.

A paper questionnaire will be provided to be completed by the subject. Responses for the FJS will then be recorded.