Effect of a too posterior placement of the tibial tunnel on the outcome 10-12 years after anterior cruciate ligament reconstruction using the 70-degree tibial guide

To examine the relationship between the radiographically assessed placement of the tibial tunnel and the long-term clinical and subjective outcome in anterior cruciate ligament-reconstructed patients. Patients were examined clinically, with subjective score systems and with standardised radiographs 10-12 years postoperatively. Only patients reconstructed with the aid of the 70-degree tibial drill guide were included. A posterior placement of the tibial tunnel was defined as > 50 % along the Amis and Jakob line (AJL). A high tunnel inclination was defined as > 75A degrees in the coronal plane. The possible linear relationships between clinical findings, subjective scores and tibial tunnel placement were investigated. Eighty-six percentage of the 96 patients were available for examination. Mean tibial tunnel inclination was 71.1A degrees (SD 4.2). No difference was found in subjective scores and knee stability between high (14 %) and low (86 %) inclination groups. Mean placement of the tibial tunnel along the AJL was 46 % (SD 5). Patients with a posterior tibial tunnel placement (24 %) had a higher incidence of rotational instability (P = 0.02). Patients with rotational instability (grade 2 pivot shift) had significant lower Lysholm score than those with grade 0 and 1 rotational instability (P = 0.001). The use of a tibial drill guide that relates to the femoral roof leads to a posterior tibial tunnel placement (> 50 % of the tibial AP-diameter) in 24 % of the patients. These patients have a significant higher proportion of rotational instability and worse subjective outcome. Case series, Level IV.