Frontal alignment in total knee arthroplasty. Comparative study between radiographic measurement and surgical navigation. / Alineación frontal en la artroplastia total de rodilla. Estudio comparativo entre medición radiográfica y con navegación quirúrgica.

OBJECTIVE: To establish the concordance between angulation of the femoro-tibial mechanical axis measured with x-rays and surgical navigation in both the pre and postoperative period after a total knee arthroplasty (TKA) was implanted. MATERIAL AND METHOD: Pre and postoperative measurements were analyzed in 88 TKA of the same model and all performed with the same surgical navigation system. The mechanical frontal angle (MFA) and femoro-tibial anatomic angle were measured before and after the TKA. The angulation was digitally measured with a teleradiography. In the navigation, the femoro-tibial angle at rest, forced varus and valgus were registered and the average of these three measurements was calculated. RESULTS: The mean preoperative MFA measured on the radiograph was 4.55°. The mean of the same angle measured on the postoperative radiograph was 1.72°, (p=0.05). The mean of the MFA measured with navigation before TKA was 3.12° and after the implant with navigation was 0.53 (P=.013). The concordance coefficient between the MFA in teleradiography and in navigation was 0.869 (P<.001) preoperatively and 0.709 postoperatively (P=.017). CONCLUSIONS: We found a strong concordance between radiographic and surgical navigation measurements of the MFA. This may imply that teleradiography is not necessary when using surgical navigation in TKA.

Alineación frontal en la artroplastia total de rodilla. Estudio comparativo entre medición radiográfica y con navegación quirúrgica / Frontal alignment in total knee arthroplasty. Comparative study between radiographic measurement and surgical navigation

Objetivo. Conocer la concordancia entre el ángulo del eje mecánico femorotibial medido en radiografías y en navegación quirúrgica, tanto en el pre como en el postoperatorio al implantar una artroplastia total de rodilla. Material y método. Se analizaron las mediciones pre y postoperatorias en 88 artroplastias totales del mismo modelo y realizadas todas con el mismo sistema de navegación quirúrgica. Se valoró el ángulo frontal mecánico (AMFFT) y anatómico femorotibial pre y posquirúrgico. Para ello se utilizó una telerradiografía en bipedestación, donde se midió el ángulo mediante técnicas digitalizadas. En la navegación se recogió el ángulo femorotibial en reposo y en varo-valgo forzado, hallándose la media de estos 3 valores. Resultados. La media del AMFFT preoperatorio medido en la radiografía fue 4,55°. La media del mismo ángulo medido en la radiografía postoperatoria fue de 1,72°, con diferencias estadísticamente significativas. La media del AMFFT medido con la navegación antes de iniciar la técnica quirúrgica fue de 3,12° y tras el implante con navegación fue de 0,53°, también con diferencias estadísticamente significativas (p=0,013). El coeficiente de concordancia entre el AMFFT preoperatorio en telerradiografía y en navegación fue de 0,869 (p<0,001) y en el postoperatorio de 0,709 (p=0,017). Conclusiones. Hemos encontrado una fuerte concordancia en el AMFFT entre la medición con radiografías y con navegación quirúrgica. Ello puede suponer que no es necesaria la realización de una telerradiografía cuando se utiliza navegación en el implante de una artroplastia total de rodilla (AU)

Objective. To establish the concordance between angulation of the femoro-tibial mechanical axis measured with x-rays and surgical navigation in both the pre and postoperative period after a total knee arthroplasty (TKA) was implanted. Material and method. Pre and postoperative measurements were analyzed in 88 TKA of the same model and all performed with the same surgical navigation system. The mechanical frontal angle (MFA) and femoro-tibial anatomic angle were measured before and after the TKA. The angulation was digitally measured with a teleradiography. In the navigation, the femoro-tibial angle at rest, forced varus and valgus were registered and the average of these three measurements was calculated. Results. The mean preoperative MFA measured on the radiograph was 4.55°. The mean of the same angle measured on the postoperative radiograph was 1.72°, (p=0.05). The mean of the MFA measured with navigation before TKA was 3.12° and after the implant with navigation was 0.53 (P=.013). The concordance coefficient between the MFA in teleradiography and in navigation was 0.869 (P<.001) preoperatively and 0.709 postoperatively (P=.017). Conclusions. We found a strong concordance between radiographic and surgical navigation measurements of the MFA. This may imply that teleradiography is not necessary when using surgical navigation in TKA (AU)