Accuracy and Stability of a New Automatic Knee Arthrometer in Diagnosing ACL Rupture

Study Overview
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Brief Summary
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We introduced an automatic knee arthrometer (AKA) and aimed to evaluate the repeatability and effectiveness thereof in diagnosing ACL rupture compared with the KT-2000.

Detailed Description
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The AKA was compared to the KT-2000 at 134 N in this study, the anterior displacement and difference of both knees of every subject were measured. The first protocol was designed to evaluate examiner effect (level of experience) and contralateral-side effect (left or right knee) in a single healthy subject, ten times, on ten consecutive days. The second was to compare the stability in 20 healthy subjects, with a single experienced examiner. Third, we recruited 200 ACL rupture and 200 healthy subjects as contrast to compare the accuracy of the devices in diagnosing ACL rupture.

Official Title
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Accuracy and Stability of a New Automatic Knee Arthrometer in Diagnosing Anterior Cruciate Ligament Rupture

Conditions
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Knee Ligament; Laxity

Intervention / Treatment
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* Diagnostic Test: Side-to-side difference (reproducibility)
* Diagnostic Test: Side-to-side difference (availability)
* Diagnostic Test: Side-to-side difference (Accuracy)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients with ACL rupture from our institution were included. All patients were diagnosed by sports medicine specialists based on clinical manifestation, combined with imaging examinations, and hospitalized for further surgery. Exclusion Criteria: Patients aged <18 or >45 years, with combined multiple knee ligament injury combinations, and/or limited range of motion of the knee (unable to flex to 20-30°)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Examiner effect group<br>Two examiners performed the test on one healthy subject with both devices for ten consecutive days. We measured the AD of both knees and calculated the ADD of every test. We evaluated the contralateral-side effect by comparing the AD standard deviations of each knee with both devices, and compared the average ADD tested by different examiners with the same device, to estimate examiner effect. | Diagnostic Test: Side-to-side difference (reproducibility)<br>* The experienced examiner performed tests on 20 healthy subjects<br>|
| Method effect group<br>The experienced examiner performed tests on 20 healthy subjects using both devices. The means and standard deviations of both knees were calculated. We examined the difference in measurements using each device to determine the method effect. | Diagnostic Test: Side-to-side difference (availability)<br>* Two examiners performed the test on one healthy subject with both devices for ten consecutive days.<br>|
| Equipment effectiveness group<br>The experienced examiner performed tests on 200 ACL ruptureand 200 healthy subjects using each device. Effectiveness was analyzed using 1.5 mm and 3 mm threshold values in ACL tears. | Diagnostic Test: Side-to-side difference (Accuracy)<br>* 200 ACL rupture and 200 healthy subjects were recruited as contrast to compare the accuracy of the devices in diagnosing ACL rupture.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Side-to-side difference （SSD） | Side-to-side difference （SSD）at 134 N | within 3 months after ACL rupture |