Anterior cruciate ligament reconstruction. The effect of tibial tunnel placement on range of motion.

In 111 patients who had anterior cruciate ligament reconstructions, postoperative radiographic measurements of anterior to posterior and medial to lateral location of the tibial tunnels were correlated with the final range of motion achieved. In the 25 patients with extension deficits of 10 degrees or more, placement of the tibial tunnel was more anterior (average, anterior 23% of the tibia) than in the remaining 86 patients with extension deficits of < 10 degrees (average, anterior 29% of tibia). This difference was statistically significant with P < 0.001. Logistic regression analysis revealed that the more anterior the placement of the tibial tunnel, the greater the loss of both flexion (P = 0.01) and extension (P = 0.002). In the 21 patients with full extension but flexion < 130 degrees, placement of the tibial tunnel tended to be more medial (average, medial 40% of the tibia) than in the 65 patients without flexion deficit (average, medial 45% of the tibia). We conclude that placement of the tibial tunnel in the "eccentric," anteromedial position may contribute to the development of flexion and extension deficits after anterior cruciate ligament reconstruction.