The Correlation Between Femoral Component Implanting Flexion Angle and Posterior Condyle Offset in Cruciate Retaining Total Knee Arthroplasty

Study Overview
=================
Brief Summary
-----------------
The main aim and scope is making measurement and comparison about the femoral component posterior offset under different femoral component implanting flexion angle in cruciate retaining total knee arthroplasty. The results may identify the influence of the flexion component implanting flexion angle on the femoral component posterior offset.

Official Title
-----------------
The Correlation Between Femoral Component Implanting Flexion Angle and Posterior Condyle Offset in Cruciate Retaining Total Knee Arthroplasty

Conditions
-----------------
Knee Osteoarthritis

Intervention / Treatment
-----------------
* Procedure: total knee arthroplasty


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: The patients undertaken the primary cruciate retaining total knee arthroplasty; using the curiate retaining total knee arthroplasty prothesis from Biomet and Smith&Nephew; Complete surgery documents and radiologic data,such as standard X-ray postoperative both at antirior-posterior position and medial-lateral position(overlap of the medial and lateral femoral condyle). Exclusion Criteria: The patients without standard X-ray postoperative both at antirior-posterior position and medial-lateral position(poor overlap of the medial and lateral femoral condyle); Complex primary total knee arthroplasty, using extra component such as trabecular metal,stem or et al.
Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| The group that the sagittal flexion angle of the femoral component less than 4°<br>The patients' knees were taken on the X-ray examination after the total knee arthroplasty on the medial-lateral position. The flexion (positive degree) or extension (negative degree) angle of the femoral component according to the anterior femoral cortex was measured. The patients with the sagittal flexion angle of the femoral component less than 4° were categorized into this group. | Procedure: total knee arthroplasty<br>* The surgeries were performed under general anesthesia. The medial parepatellar incision was introduced during the TKA. The femoral component size was selected according to the intro-operative measurement. The osteotomy was done according to the intramedullary guide and the cutting guide. After the proximal tibial osteotomy was finished, the cruciate-retaining Total Knee System was used. The lateral rotation of the femoral component was determined by the gap-balancing technique.<br>|
| The group that the sagittal flexion angle of the femoral component over 4°<br>The patients' knees were taken on the X-ray examination after the total knee arthroplasty on the medial-lateral position. The flexion (positive degree) or extension (negative degree) angle of the femoral component according to the anterior femoral cortex was measured. The patients with the sagittal flexion angle of the femoral component over 4° were categorized into this group. | Procedure: total knee arthroplasty<br>* The surgeries were performed under general anesthesia. The medial parepatellar incision was introduced during the TKA. The femoral component size was selected according to the intro-operative measurement. The osteotomy was done according to the intramedullary guide and the cutting guide. After the proximal tibial osteotomy was finished, the cruciate-retaining Total Knee System was used. The lateral rotation of the femoral component was determined by the gap-balancing technique.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Posterior Femoral Offset | The posterior femoral offset was defined as the maximal thickness of the posterior condyle projecting posteriorly to a straight line drawn as the extension of the posterior femoral shaft cortex on the medial-lateral position of the X-ray examination. | 1 week after the surgery | 
| Posterior Femoral Offset Ratio | The posterior femoral offset ratio was defined as the maximal thickness of the posterior condyle projecting posteriorly to a straight line drawn as the extension of the posterior femoral shaft cortex, divided by the maximal thickness of the posterior condyle projecting posterior to a straight line drawn as the extension of the anterior femoral shaft contex on the medial-lateral position of the X-ray examination. | 1 week after the surgery | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Sagittal flexion angle, Posterior femoral offset, Cruciate-retaining total knee arthroplasty