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

摘要

Purpose: 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. Methods: 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 >75° in the coronal plane. The possible linear relationships between clinical findings, subjective scores and tibial tunnel placement were investigated. Results: Eighty-six percentage of the 96 patients were available for examination. Mean tibial tunnel inclination was 71.1° (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). Conclusions: 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. Level of evidence: Case series, Level IV.