A New Technique to Produce Anatomical Alignment Results With Less Midflexion Instability in Total Knee Arthroplasty

Study Overview
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Brief Summary
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Beside the current standard of classical mechanical alignment of total knee replacements, increased interest is being shown in anatomical alignment. However, no surgical technique is capable of controlling the stability of the joint in midflexion. The purpose of the present study was to present and evaluate a new surgical technique, which aims to reduce the need for soft-tissue release and optimize stability in midflexion.

Conditions
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Osteoarthritis, Knee

Intervention / Treatment
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* Procedure: Implantation of TKA using the gap technique
* Procedure: Implantation of TKA using anatomical alignment


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: The patients were to undergo surface replacement due to primary osteoarthritis of the knee Exclusion Criteria: Joints that had undergone open surgery beforehand (e.g. high tibial osteotomy, fracture treatment) were excluded.
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: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: gap technique (GT)<br>The patients receive a total knee arthroplasty using the established gap technique (gold standard serving as control). The intervention is the implantation of a total knee arthroplasty with this specific technique. Implantation of TKA using the gap technique is the intervention. Intervention is not a drug but a specific operative technique. | Procedure: Implantation of TKA using the gap technique<br>* Implantation of total knee arthroplasty using a specific operative technique (GT) serving as control.<br>|
| Experimental: anatomical alignment (AA)<br>The patients receive a total knee arthroplasty using the new anatomical alignment technique (experimental). The intervention is the implantation of a total knee arthroplasty with this specific technique. Implantation of TKA using anatomical alignment Intervention is not a drug but a specific operative technique. | Procedure: Implantation of TKA using anatomical alignment<br>* Implantation of total knee arthroplasty using a specific operative technique (AA) being experimental.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement of midflexion instability (i.e. tibofemoral gap medially and laterally) in 30° and 60° of flexion | The outcome measures are given in mm. | intraoperatively immediately before implantation of definite implants. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| performance of soft tissue release (yes / no) and extend of release if done. | The surgeon documents postoeperatively if a soft tissue release was done or not and what extend a release had. The outcome measure is given in numbers (0 ... 4). | intraoperatively | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Total knee arthroplasty, Midflexion instability, Gap technique, Anatomical alignment