Ryo Shimizu1, Nobuo Adachi2, Minoru Ishifuro3, Atsuo Nakamae2, Masakazu Ishikawa2, Masataka Deie4, Mitsuo Ochi5. 1. Department of Orthopaedic Surgery, Division of Clinical Medical Science, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. Electronic address: shimiryo@hiroshima-u.ac.jp. 2. Department of Orthopaedic Surgery, Division of Clinical Medical Science, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. 3. Department of Higher Medical Imaging, Hiroshima University Hospital Clinical Support, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan. 4. Department of Orthopaedic Surgery, Aichi Medical University Hospital, 1-1 Yasakokarimata, Nagakute, Aichi 480-1195, Japan. 5. Hiroshima University, 1-3-2 Kagamiyama, Higashihiroshima, Hiroshima 739-8511, Japan.
Abstract
BACKGROUND: The purpose of this study was to evaluate bone tunnel changes following anterior cruciate ligament (ACL) reconstruction during the early postoperative period using computed tomography (CT), and to understand the impact of postoperative immobilization on these changes. METHODS: Twenty patients who underwent double-bundle ACL reconstruction using hamstring tendon autografts were included. We subcategorized patients into two groups: patients who underwent isolated ACL reconstruction and had three days of knee immobilization (Group A, n=10); and patients with concomitant meniscus injuries who underwent ACL reconstruction and meniscus repair simultaneously (Group B, n=10) had their knees immobilized for two weeks after surgery. Bone tunnel enlargement was evaluated using CT imaging at one to three days, two weeks, one month, three months and six months after surgery. The cross-sectional area of the femoral and tibial tunnels was measured, and enlargement rate was calculated. The tunnel center location at two weeks after surgery was also evaluated. RESULTS: The mean cross-sectional area adjacent to the joint space of the femoral and tibial tunnels significantly increased immediately after surgery, especially in the first month (P<0.01). However, after one to six months they were not increased (P>0.01). There was no significant difference in tunnel enlargement rate between group A and B. Tunnel center location changed even in the first two weeks. CONCLUSIONS: Bone tunnel enlargement following double-bundle ACL reconstruction occurred at an earlier time point after surgery than anticipated. Postoperative immobilization could not prevent bone tunnel enlargement, but might prevent tunnel migration.
BACKGROUND: The purpose of this study was to evaluate bone tunnel changes following anterior cruciate ligament (ACL) reconstruction during the early postoperative period using computed tomography (CT), and to understand the impact of postoperative immobilization on these changes. METHODS: Twenty patients who underwent double-bundle ACL reconstruction using hamstring tendon autografts were included. We subcategorized patients into two groups: patients who underwent isolated ACL reconstruction and had three days of knee immobilization (Group A, n=10); and patients with concomitant meniscus injuries who underwent ACL reconstruction and meniscus repair simultaneously (Group B, n=10) had their knees immobilized for two weeks after surgery. Bone tunnel enlargement was evaluated using CT imaging at one to three days, two weeks, one month, three months and six months after surgery. The cross-sectional area of the femoral and tibial tunnels was measured, and enlargement rate was calculated. The tunnel center location at two weeks after surgery was also evaluated. RESULTS: The mean cross-sectional area adjacent to the joint space of the femoral and tibial tunnels significantly increased immediately after surgery, especially in the first month (P<0.01). However, after one to six months they were not increased (P>0.01). There was no significant difference in tunnel enlargement rate between group A and B. Tunnel center location changed even in the first two weeks. CONCLUSIONS:Bone tunnel enlargement following double-bundle ACL reconstruction occurred at an earlier time point after surgery than anticipated. Postoperative immobilization could not prevent bone tunnel enlargement, but might prevent tunnel migration.