Reliability of Early Postoperative Radiographic Assessment of Tunnel Placement After Anterior Cruciate Ligament Reconstruction

Purpose To evaluate the interobserver and intraobserver reliability of radiographic assessment of tunnel placement in anterior cruciate ligament reconstruction. Methods Seven sports fellowship–trained orthopaedic surgeons in the Multicenter Orthopaedic Outcomes Network (MOON) group participated in the study. We prospectively enrolled 54 consecutive patients after primary anterior cruciate ligament reconstruction. Postoperative plain radiographs were obtained including a full-extension anteroposterior view of the knee, a lateral view of the knee in full extension, and a notch view at 45° of flexion (Rosenberg view). Three blinded reviewers performed 8 different radiographic measurements including those of Harner and Aglietti/Jonsson. Intraclass correlation coefficients were used to determine reliability of the measurements. Intrarater reliability was assessed by repeated measurements of a subset of 20 patient images from 1 institution, and inter-rater reliability was assessed by use of all 54 sets of films from a total of 4 institutions. Results Intraobserver reliability for femoral measures ranged from none to substantial, with notch height having the worst results. Intraobserver reliability was moderate to almost perfect for tibial measures. Interobserver reliability ranged from slight to moderate for femoral measures. The Harner method for determining tunnel depth was more reliable than the Aglietti/Jonsson method. Interobserver reliability for tibial measures ranged from fair to substantial. The presence of metal interference screws did not improve reliability of measurements. Conclusions Postoperative radiographs are easily obtained, but our results show that radiographic measurements are of quite variable reliability, with most of the results falling into the fair to moderate categories. Level of Evidence Level III, diagnostic study.