Measurement of knee articulation laxity by videofluoroscopy image analysis: CINARTRO

Abstract

Several methods are used to evaluate knee articulation during movement, such as the Tibio Femoral Contact Point migration or the Instantaneous Centre of Rotation displacement and even the Moment Arm variations during extension. Such evaluation is important in case of Anterior Cruciate Ligament reconstruction or Total Knee Replacement, but unfortunately, it is only available in research settings. We have devised a novel clinical methodology based on serial images of knee movement videofluoroscopy, which are interactively analysed to allow automatic determination of kinematics parameters. The method, called CINARTRO, compares values with the contralateral knee and produces a standard Clinical Document Architecture file ready for Electronic Medical Record systems. To correct the "pin cushion" effect of X ray intensifiers, a 10 mm apart lead spheres phantom was developed. To validate the interactive selection of anatomical points, cadaver limbs were marked with lead markers and compared with points marked on the blind image. Anterior Cruciate Ligament (injured and reconstructed) and contralateral Moment Arms averages of 53mm, 39mm and 43mm respectively were found. Similarly the Total Knee Replacement patient`s Moment Arm was reduced to 33mm. These findings justify the use of our methodology to help clinicians during rehabilitation follow-up.

Migración del Punto de Contacto Tibio-Femoral y variación del Brazo de Palanca del Ligamento Rotuliano durante la extensión de la rodilla sana, con Ligamento Cruzado Anterior roto y reconstruido

“…Es utilizado en personas después de una lesión del LCA y durante la rehabilitación, dando datos cinemáticos de valor clínico al compararlos con su contraparte sana y los documenta en el registro clínico electrónico. [2] II. METODOLOGÍA CINARTRO CINARTRO es capaz de leer las imágenes de videofluoroscopia en formato DICOM producidas por algún equipo de rayos X, como por ejemplo un arco en C. Se pueden estudiar las rodillas durante el movimiento en cadena cinematica abierta (La toma de la imagen se realiza mientras la persona se encuentra sentada) o cerrada (La imagen se obtiene mientras la persona sube un escalón) .…”