Patient-specific Instruments as a Standard Procedure in Total Knee Arthroplasty

Study Overview
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Brief Summary
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Description of logistics, learning curve and radiological results in 70 patients treated with patient specific instrumentation in total knee arthroplasty as a standard procedure

Detailed Description
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The Orthopaedic Clinic Gersthof is a teaching hospital, where the entire spectrum of joint replacements with emphasis on hips and knees is performed. Twenty surgeons perform TKAs at our institution, with approximately 400 TKAs implanted per year. The PSI system of Smith &Nephew® (Patient-Matched Cutting Blocks [PMCB]; the VISIONAIRE® technology) is applied. The preoperative image modality is based on a long leg standing X-ray as well as an MRI of the knee. The Genesis II® Endoprosthesis (Smith & Nephew®) is used as the TKA implant. This study is a observational monocentric prospective study. Estimated enrollment: 70 Enrollment time: September 2011-October 2012 Primary outcome: Alignment The postoperative X-rays (AP, lateral view, and long leg standing), taken 7-to-10 days after surgery are evaluated in terms of component position and restoration of the mechanical alignment. X-rays are routinely monitor-guided but not calibrated at our institution. As a secondary outcome the learning curve is evaluated using the following parameters collected during surgery: the fit of the cutting blocks, changes of the implant size, bony recuts, soft tissue releases, and changes in inlay size. Gap balancing was subjectively judged by the operating surgeon. Operation time, number of blood transfusions, and early postoperative complications were recorded within the first 14 days after surgery.

Official Title
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Patient-specific Instruments as a Standard Procedure in Total Knee Arthroplasty: Logistics, Learning Curve, and Postoperative Radiological Results in 70 Patients

Conditions
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Alignment

Intervention / Treatment
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* Device: Total knee arthroplasty (TKA) (Smith &Nephew®)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Indication for TKA Genesis II endoprosthesis Operated using patient specific instruments (VISIONAIRE) Exclusion Criteria: contraindication for MRI varus/ valgus deformity >15 degrees

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 |
| --- | --- |
| Patients treated with Patient specific instruments in TKA<br> | Device: Total knee arthroplasty (TKA) (Smith &Nephew®)<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Alignment | Alignment measured on monitor-guided x-rays: Mechanical Alignment: Hip-Knee-Ankle angle in degrees [°] Alignment of the tibial and femoral component in the sagittal and coronal plane [°] | Postoperative x-ray (7-10 days after surgery) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Learning curve | In order to evaluate the learning curve associated with using VISIONAIRE® technology for TKA, the following parameters are registered during surgery: the fit of the cutting blocks[subjective grading by the surgeon], changes of the implant size[number of changes], bony recuts[number of recuts], soft tissue releases[number of releases, kind of release], and changes in inlay size [number of inlay changes]. Gap balancing is subjectively judged by the operating surgeon. Operation time[minutes], number of blood transfusions[units], and early postoperative complications associated with the treatment [kind and number] within the first 14 days after surgery are recorded. | Intraoperative and early postoperative period (up to 14 days after surgery) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Total knee arthroplasty, Patient specific instruments, Patient matched cutting blocks, Alignment, Learning curve, VISIONAIRE