Kinematic Versus Mechanical Alignment in Total Knee Replacement

Study Overview
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Brief Summary
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This prospective controlled double-blind randomized study compares kinematic and mechanical alignment in TKA (Total knee arthroplasty). A total of 120 patients will be included and the surgery will be performed using CT based 3D printed PSI(Patient Specific Instruments) Cutting guides.

Detailed Description
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Total knee arthroplasty (TKA) is known, to significantly improve function and satisfaction in arthritic knee patients; nevertheless, a substantial percentage of these patients are not fully satisfied. Thus, several authors reported significantly improved outcomes after slightly under correcting varus knees after TKA. The concept of kinematic alignment (KA) even more addresses the patient´s individual anatomy with three-dimensional restoration of individual axes, joint lines and joint envelope of laxity. The aim of this prospective randomized study was to demonstrate equivalence between mechanical and kinematic alignment in restoring knee function in terms of subjective and objective outcomes. In this prospective randomized controlled double-blind study 120 patients with osteoarthritic knees will be treated with a Medial Pivot TKA (Medacta Sphere GMK). The patients are divided into two groups. Group A receive the TKA using mechanical alignment principles, group B receive the kinematic alignment. The surgical technique was equal in both groups. CT-based 3D printed PSI cutting blocks were used for the saw cuts. Pre and postoperative standard x-rays were performed. To determine the subjective and objective outcomes the OKS(Oxford Knee Score), the KSS(Knee Society Sore), the FJS-12(Forgotten Joint Score) and the WOMAC Score were collected.

Official Title
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Kinematic Versus Mechanical Alignment in Total Knee Replacement: a Randomized Double-blinded Controlled Study

Conditions
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Total Knee Replacement

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Symptomatic osteoarthritis of the knee Primary TKA UCLA Score (University of California, Los Angeles Score)>/= 4 mMPTA: 85°- 90° Sum of mMPTA(mechanical medial proximal tibial angle) and mLDFA(mechanical lateral distal femoral angle) between 3°varus and 2°valgus from neutral Exclusion Criteria: Minor Patient Pregnant or breast feeding woman Difference in the radius of medial and lateral condyles >2mm Previous osteotomy around the knee BMI >40 Ligament instability likely to require higher level of constraint Previous infection or inflammatory disease Any Patient who cannot or will not provide informed consent for participation in the study

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| MA (mechanical alignment)<br>Patients in group MA (mechanical alignment) will be operated according to mechanical implantation technique. In the mechanical group, femoral and tibial cutting blocks will be designed for a 0-degree angle according to the mechanical axis. Femoral rotation will be aligned with the femoral trans-epicondylar axis. Tibial rotation will follow femoral rotation. | |
| KA (kinematic alignment)<br>Patients in group KA (kinematic alignment) will be operated according to kinematic implantation technique. The kinematic cutting blocks will be designed to resurface the femoral and tibial bones to restore each patient´s pre-arthritic anatomy and Joint line. Based on a available CT dat the prearthritic anatomy is reconstructed by compensating bone defects and restoring the physiological cartilage height of 1,7mm. Femoral Flexion is evaluated by the anterior Cortex of the distal femur, tibia slope is defined to 3° due to ACL (Anterior Cruciate Ligament) loss, but cab be adapted during surgery. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee Society Score (KSS) | The Knee Society Scoring System is a validated and responsive method for assessing objective and subjective outcomes after total and partial knee arthroplasty. Minimum: 0 (worst), Maximum: 100 (best) | 3 months postoperative | 
| Knee Society Score (KSS) | The Knee Society Scoring System is a validated and responsive method for assessing objective and subjective outcomes after total and partial knee arthroplasty. Minimum: 0 (worst), Maximum: 100 (best) | 12 months postoperative | 
| Knee Society Score (KSS) | The Knee Society Scoring System is a validated and responsive method for assessing objective and subjective outcomes after total and partial knee arthroplasty. Minimum: 0 (worst), Maximum: 100 (best) | 24 months postoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Forgotten Joint Score (FJS-12) | The FJS Knee was designed to assess patient outcome in patients undergoing conservative or operative treatment of the knee. This questionnaire shows its strengths in patients with a good level of knee function and a low pain level. It has been designed specifically to reduce ceiling effects commonly associated with many PRO measures in this patient group, e.g. when assessing short- to mid-term results in total knee arthroplasty patients. Minimum: 0 (worst), Maximum: 100 (best) | 3 months postoperative | 
| Forgotten Joint Score (FJS-12) | The FJS Knee was designed to assess patient outcome in patients undergoing conservative or operative treatment of the knee. This questionnaire shows its strengths in patients with a good level of knee function and a low pain level. It has been designed specifically to reduce ceiling effects commonly associated with many PRO measures in this patient group, e.g. when assessing short- to mid-term results in total knee arthroplasty patients. Minimum: 0 (worst), Maximum: 100 (best) | 12 months postoperative | 
| Forgotten Joint Score (FJS-12) | The FJS Knee was designed to assess patient outcome in patients undergoing conservative or operative treatment of the knee. This questionnaire shows its strengths in patients with a good level of knee function and a low pain level. It has been designed specifically to reduce ceiling effects commonly associated with many PRO measures in this patient group, e.g. when assessing short- to mid-term results in total knee arthroplasty patients. Minimum: 0 (worst), Maximum: 100 (best) | 24 months postoperative | 
| Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) | The WOMAC Score was developed in 1982 and is a Patient Reported Outcome (PRO) instrument to assess the effects of osteoarthritis of the hip and/or knee joint in affected patients. The WOMAC-Score contains 24 questions and is able to assess the effects of osteoarthritis of the hip and/or knee joint with regard to three subscales: Pain - 5 questions Stiffness - 2 questions Physical function - 17 questions Minimum: 0 (best), Maximum: 100 (worst) | 3 months postoperative | 
| Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) | The WOMAC Score was developed in 1982 and is a Patient Reported Outcome (PRO) instrument to assess the effects of osteoarthritis of the hip and/or knee joint in affected patients. The WOMAC-Score contains 24 questions and is able to assess the effects of osteoarthritis of the hip and/or knee joint with regard to three subscales: Pain - 5 questions Stiffness - 2 questions Physical function - 17 questions Minimum: 0 (best), Maximum: 100 (worst) | 12 months postoperative | 
| Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) | The WOMAC Score was developed in 1982 and is a Patient Reported Outcome (PRO) instrument to assess the effects of osteoarthritis of the hip and/or knee joint in affected patients. The WOMAC-Score contains 24 questions and is able to assess the effects of osteoarthritis of the hip and/or knee joint with regard to three subscales: Pain - 5 questions Stiffness - 2 questions Physical function - 17 questions Minimum: 0 (best), Maximum: 100 (worst) | 24 months postoperative | 
| Oxford Knee Score (OKS) | The OKS questionnaire consists of 12 questions that cover function and pain of the knee. Each question is scored from 0 to 4 (0 being the worst outcome and 4 being the best). The overall score is the sum of all items and can range from 0 to 48, with higher scores corresponding to better outcomes. The OKS has a big ceiling effect and cannot differentiate between good and very good results. However, the most of the researchers world wide use the OKS as a reference. | 3 months postoperative | 
| Oxford Knee Score (OKS) | The OKS questionnaire consists of 12 questions that cover function and pain of the knee. Each question is scored from 0 to 4 (0 being the worst outcome and 4 being the best). The overall score is the sum of all items and can range from 0 to 48, with higher scores corresponding to better outcomes. The OKS has a big ceiling effect and cannot differentiate between good and very good results. However, the most of the researchers world wide use the OKS as a reference. | 12 months postoperative | 
| Oxford Knee Score (OKS) | The OKS questionnaire consists of 12 questions that cover function and pain of the knee. Each question is scored from 0 to 4 (0 being the worst outcome and 4 being the best). The overall score is the sum of all items and can range from 0 to 48, with higher scores corresponding to better outcomes. The OKS has a big ceiling effect and cannot differentiate between good and very good results. However, the most of the researchers world wide use the OKS as a reference. | 24 months postoperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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KA (kinematic alignment), TKA (Total knee arthroplasty)