Estudio de los túneles femoral y tibial para la ligamentoplastia de L.C.A. mediante T.A.C. y su repercusión clínica a largo plazo

espanolEstudio observacional analitico de cohorte historica que incluye a 30 pacientes intervenidos entre 1993 y 1997, mediante la tecnica SAC para la reconstruccion del LCA. La media de seguimiento fue de 12.5 anos (rango 10-15 anos). Se descartaron 9 casos por no cumplir el seguimiento completo, 2 por ser intervenidos de la rodilla contra-lateral y uno por fallecimiento. Criterios de exclusion: injertos artificiales, otras lesiones ligamentosas asociadas, lesiones condrales grado II o mayor (sin reconstruccion mediante mosaicoplastia), historia natural de infeccion, mal-alineamiento del miembro afectado y cirugia previa de ligamentoplastia. Metodos de valoracion clinica: test de Lachman, cajon anterior, test de Jerk, test del "pivot shift" y KT 2000 (15L, 20L, 30L, MMF y clasificacion de Segawa). Escalas de valoracion clinica: IKDC, Lysholm, Tegner, WOMAC. Metodos de valoracion radiologica: criterios de Fairbank, escala radiologica IKDC. Mediciones realizadas mediante TAC (preoperatorio, intermedio, final): tunel tibial frontal (angulo , indice M2), tunel tibial sagital (angulo ? , indice M4, grado de congruencia), tunel frontal femoral tunnel (zona horaria, angulo ), tunel sagital femoral (Metodo de Aglietti, angulo ). Angulo de divergencia de tuneles (angulo ). Ensanchamiento de tuneles (criterios de Nebelung). Tambien se analizo la relacion entre los hallazgos radiologicos de la TAC y radiografias simples con los resultados clinicos. Conclusiones: - Hay una mayor incidencia de ensanchamiento en los tuneles tibiales que en los femorales. - Los tuneles tibiales se siguen dilatando hasta el final del periodo de seguimiento. - La expansion del tunel tibial esta relacionada directamente con el aumento del angulo frontal tibial - Inversamente, con la longitud de la pastilla tibial, el angulo de divergencia de tuneles y el grado de congruencia. - El ensanchamiento del tunel tibial, no es un parametro decisivo para predecir si una rodilla va a resultar inestable a largo plazo. - El ensanchamiento del tunel tibial, en el plano sagital, esta relacionado con cambios degenerativos a largo plazo. - La localizacion del tunel femoral es el factor que mas influye en los resultados de estabilidad de rodilla, medidos objetivamente con el artrometro. - El tunel femoral demasiado "vertical" o perpendicular a la interlinea articular, esta relacionado con peores resultados de estabilidad anterior y rotacional de rodilla. - Cuanto mayor es el angulo frontal femoral, mayor incidencia de cambios degenerativos en la escala de Fairbank al final del seguimiento (incremento de grado 0 a I). - El aumento del angulo frontal tibial esta relacionado con peores resultados en la escala de Segawa. - Las complicaciones secundarias a un tunel femoral mal localizado, no pueden ser compensadas con un buen injerto, ni con los mejores metodos de fijacion ni con un correcto programa de rehabilitacion. - La tecnica SAC, disenada para realizar los tuneles de forma independiente, es idonea porque permite colocar el tunel femoral en la posicion mas adecuada para evitar los problemas de inestabilidad anterior y rotacional de rodilla. - Es necesario hacer mas estudios con seguimientos largos que sirvan para valorar la evolucion natural de las ligamentoplastias del LCA. EnglishBackground: ACL lesion is a major epidemiology problem. In the U.S.A. one of 3000 people sustain an ACL rupture per year. In other words, in the U.S.A. 100.000 A.C. L. reconstruction procedures are performed every year, with good results ranging from 75% to 90%. In 2001 in Spain 16821 A.C. L. reconstructions have been performed, with a 4/1000 prevalence ratio. A great variety of surgical techniques have been designed when using hamstring tendon grafts and many results have been published in the last years. However few of them are long term studies. Because of mentioned above, we describe our late clinical and radiographic results with the S.A.C. technique (cortical anchoring system) for A.C. L. reconstruction as well as the correlation between widening and position of the tunnels with clinical and radiologic final follow up. We also determine the usefulness of x-ray and CT scan to assess the results of the surgical technique. Methodology: This observational historical cohort study includes 30 patients operated between April 1993 and November 1997, with a mean follow up of 12.5 years (range 10-15 years), 28 were males and 2 females with a mean age of 36 years (range 19-59 years). Mean time elapsed until surgery was 81 days (range 16-240 days). 16 rigth and 14 left knees were included. Exclusion criteria: a) Leeds Keio artifitial grafts b) Other ligamentous lesions c) Chondral pathology grade II o greater (Outerbridge classification) when mosaicplasty is not indicated d) Joint infection in any postoperative period e) Malaligment of affected lower limb that requires osteotomy f) Previous A.C. L. reconstruction S.A.C. surgical technique was described in detail as well as rehabilitation postoperative protocol. Clinical assessment methods: Lachman test, anterior drawer test, Jerk test, pivot shift test and KT 2000 (15L, 20L, 30L, MMF, QA and Segawa scale). Also IKDC, Lysholm, Tegner, WOMAC scales were applied. Radiological assessment methods: Fairbank criteria and radiological IKDC scale. CT scan was performed in inmediate postoperative (15 days before surgery), intermediate (6-12 months after surgery) and final follow up (at least 10 years after surgery). CT scan assessment measurements: frontal tibial tunnel (ā angle, M2 index), sagittal tibial tunnel (đ angle, M4 index and congruence grade), frontal femoral tunnel (clock zones, Ѣ angle), sagittal femoral tunnel (Aglietti method, ē angle). Tunnel divergence angle (ĉ angle). Tunnel widening (Nebelung criteria). Conclusions: -Greater incidence of tibial tunnel widening. - Tibial tunnel continues dilation increase until final follow up. - Tibial tunnel expansion is related with increase of frontal tibial angle and decrease of bone plug length, tunnel divergence angle and congruence grade. - Tibial tunnel widening is not a valid parameter to assess long term instability of the knee. -Tibial tunnel widening in the sagittal plane is related with long term degenerative changes. - Femoral tunnel location is the most important factor for KT 2000 results. - Femoral tunnel close to 90o in frontal plane, is related with poor results in both anterior and rotational stability of the knee. - Increase of frontal femoral angle is related with a higher incidence of degenerative changes in Fairbank scale. - Increase of frontal tibial angle is related with poor results in Segawa scale. - A malposition of a femoral tunnel cannot be corrected with a appropriate fixation system. - S.A.C. technique is suitable to perform femoral tunnel in a correct position in order to avoid anterior and rotational knee instability. - More long term studies are needed to assess A.C. L. reconstruction techniques.