Knee Arthroplasty Performed With Conventional and Customized Instrumentation

Study Overview
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Brief Summary
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The main purpose of this study is to determine whether the surgical time required for primary total knee arthroplasty is significantly less when performed with Customized Patient Instrumentation (CPI) than with conventional instrumentation. Each case will be recorded by video camera, in order to time the length of surgery and each surgical step. The number of surgical trays required for each case will be recorded. As an additional endpoint, the investigators will measure limb and component alignment on x-rays to determine if these two methods achieve equivalent alignment results. The thickness of bone cuts will be compared to the surgical plan and to each other. The primary hypothesis is that the use of customized patient instrumentation will reduce the operative time required for total knee arthroplasty.

Detailed Description
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Patient-specific instrumentation (PSI) has been developed for total knee arthroplasty (TKA) with several potential advantages over traditional instrumentation (TI). Shortened surgical time, fewer surgical instruments, and improved alignment are some of these proposed advantages. We sought to examine these assertions. 52 patients (26 per group) were enrolled in a prospective, randomized trial comparing CT-based PSI with TI. No difference was seen in average patient age (68 years) or BMI (31) between groups (p=0.84 and p=0.89), although there were more males in the PSI group (14 vs 7, p=0.002). A single surgeon and consistent staff performed the surgeries with the same knee prostheses, and all cases were videotaped to measure the length of surgery and each individual step. Any additional bone cuts, size changes, or ligament releases made to achieve correct alignment and balance were documented. The number of instrument trays opened for each case was recorded. Postoperative long alignment and lateral radiographs were taken to measure the coronal and sagittal plane component alignment and mechanical axis in each patient.

Official Title
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A Prospective, Randomized Evaluation of Total Knee Arthroplasty Performed With Conventional and Customized Patient Instrumentation

Conditions
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Knee Arthritis

Intervention / Treatment
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* Device: Customized Patient Instrumentation
* Device: Traditional Instrumentation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient requires unilateral primary total knee arthroplasty Exclusion Criteria: Body mass index greater than 41 Previous ipsilateral hip or ankle replacement Knee flexion contracture greater than 20 degrees
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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Traditional Instrumentation<br>Control group: Cases performed with traditional surgical instruments | Device: Traditional Instrumentation<br>* Traditional surgical instruments will be used to make bone cuts and size the components in this control group.<br>|
| Experimental: Customized Patient Instrumentation<br>Experimental group: Cases performed with custom instruments specifically made for each patient using pre-op CT scans. | Device: Customized Patient Instrumentation<br>* Custom cutting guides based on computed tomography (CT) images of the patient's leg are used to make the bone cuts and select the implant size.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length of Surgery | Time elapsed from skin incision to wound closure (in seconds) | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length of Each Surgical Step (in Seconds) | surgical exposure, tibial alignment and resection, femoral distal cut, extension gap balancing, sizing the femur, 4 finishing femoral cuts, posterior releases, patellar resection, trial components, tibial tray preparation, cleanup/ prep for cement, cementing femur, cementing tibia, cementing patella, and closure | 1 day | 
| Number of Instrument Trays Required |  | 1 day | 
| Limb Alignment (Mechanical Axis) | Alignment is measured on 4 month postoperative radiograph in degrees. The goal is a mechanical axis between and femur and tibia of 0 degrees. Varus alignment (bow-legged) is shown as a negative number in degrees away from 0. Valgus alignment (Knock-kneed) is expressed as a positive number in degrees away from 0. | 4 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Total Knee Arthroplasty, Instrumentation