Clinical and radiographic results of ACL reconstruction: a 5-to 7-year follow-up study of outside-in versus inside-out reconstruction techniques

This study compared the clinical outcome of anterior cruciate ligament (ACL ) reconstruction between the inside-out and the outside-in techniques and a ssessed radiographically whether surgical technique affects the position an d direction of the bone tunnels. A patellar tendon ACL reconstruction was p erformed in 141 patients with inside-out (group I, n=78) and outside-in tec hnique (group Ii, n=63). Clinical results were evaluated using the Internat ional Knee Documentation Committee (IKDC) form; radiographic study was perf ormed in anteroposterior, lateral, and notch views. Overall results in grou p I were normal in 23% of cases, nearly normal in 55%, and abnormal in 22%; in group II there were normal results in 19% of cases, nearly normal in 57 %, abnormal in 19%, and severely abnormal in 5%. Radiographic examination i dentified important differences between the two groups. The main difference s between the two surgical techniques were related to the positioning of th e femoral tunnel. With the inside-out technique the femoral tunnel was sign ificantly more vertical, both in the frontal and the sagittal planes. Moreo ver, the femoral tunnel was higher when drilled from the inside, but the di fference between the two techniques was not statistically significant. The differences found between the two techniques regarding the tibial tunnel we re not significant, although in the inside-out group the tibial tunnel seem ed slightly more lateral, vertical, and posterior. Moreover, we observed a greater risk of bone-screw divergence on the femur in the inside-out group. This divergence was greatest in the sagittal plane. However, we observed n o effect of this bone-screw divergence on the stability of the knee at foll owup.