Open Versus Arthroscopic Meniscus Allograft Transplantation: Magnetic Resonance Imaging Study of Meniscal Radial Displacement

Purpose: In this imaging study, the radial displacement of meniscal allograft transplants (MATs), inserted with 2 different techniques, namely open soft-tissue fixation and arthroscopic bone tunnel fixation, was compared 1 year postoperatively. Methods: In this study, 37 patients received MATs: 16 MATs (10 lateral and 6 medial) were inserted by an open soft-tissue technique (open MATs), whereas 21 MATs (14 lateral and 7 medial) were implanted by an arthroscopic bone tunnel procedure (arthroscopic MATs). Radial displacement, in millimeters, was evaluated 1 year postoperatively on 1.5-T magnetic resonance images. The number of MATs with radial displacement larger or smaller than 3 mm was determined. To compare radial displacement of open versus arthroscopic MATs, the Mann-Whitney U test was used. Results: The radial displacement of open lateral and medial MATs was significantly larger (all reported P < .02) than that of arthroscopic MATs. In all cases, both open and arthroscopic, the radial displacement of MATs was significantly larger (all reported P < .007) than that of normal menisci. Radial displacement of less than 3 mm was found in 0 of 6 patients with open medial MATs versus 6 of 7 patients with arthroscopic MATs and was found in 1 of 10 patients with open lateral MATs versus 4 of 14 patients with arthroscopic MATs. Conclusions: The radial displacement of MATs arthroscopically inserted with bone tunnel fixation is significantly less than the radial displacement of MATs inserted with open soft-tissue fixation. In addition, normal menisci displace significantly less than meniscal allografts. The clinical importance of radial displacement remains to be determined. Level of Evidence: Level III, retrospective comparative study.