The knee is a joint exposed to stress and prone to ligamentous injuries. The anterior cruciate ligament is the most commonly injured, most commonly in the anteromedial bundle, its evaluation is performed by traditional and innovative methods. Previously we presented the Pivot Shift app to diagnose and classify posterolateral bundle injury.
An application for mobile phones has been developed using the gyroscopes and accelerometers built into a mobile phone. The hypothesis is to stage the translational instability of the knee, seeking to reduce the interpersonal variance.
Materials And Methods
A technological application designed by biomedical engineers from the Chihuahua orthopedic group was used on smartphones, including young, healthy patients of both genders. The measurements produced by the application were analyzed with an intraclass correlation coefficient regarding the time of the maneuver and the amplitude of the maximum speed.
On the other hand, the results of this test were compared with those of the KT-1000 arthrometer to obtain a relationship of the results with a scale which would indicate a degree of injury.
Two test circuits were carried out, with 11 evaluators and 20 tests each, positioning the subjects at a flexion angle of 30° in the horizontal axis. In the first circuit there was a free execution style of the maneuver. In the second circuit instructions were given for the maneuver technique, separating the evaluators into two groups of 5 at random and a control evaluator ("fixed foot" group and "without fixation" group), seeking comparison.
The essential factors for the best result of the application were classified. In the intraclass correlation coefficient (ICC) analysis, variability was verified, with intra- and interobserver relationships of less than 70%. During the second circuit, the same mathematical analysis was performed, and when calculating the ICC, higher results were obtained between Intra and interobserver samples per evaluator and per evaluation group, reaching 80% in several evaluators, demonstrating the need to standardize the maneuver for best results.
The instrument is valid for the translational measurement of the ACL.
A quantitative analysis of the maneuver can be performed through the application.
Digital arthrometry seems to be the path towards the development of precise and objective evaluation methods for translational instability, with all the advantages that an early diagnosis and classification before any surgical treatment can offer.