2015 ISAKOS Biennial Congress ePoster #1214
Effects of Graft Coverage With an ACL Remnant Tissue on Pivot Shift Kinematics After Anatomic Double-Bundle ACL Reconstruction: Evaluations With an Electromagnetic Sensor System
Masashi Yokota, MD, PhD, Futami, Hokkaido JAPAN
Nobuto Kitamura, MD, PhD, Sapporo, Hokkaido JAPAN
Eiji Kondo, MD, PhD, Sapporo, Hokkaido JAPAN
Jun Onodera, MD, PhD, Sapporo, Hokkaido JAPAN
Yasuyuki Kawaguchi, MD, PhD, Ikoma, Nara JAPAN
Keiko Goto, MD, Sapporo, Hokkaido JAPAN
Susumu Wada, MD, Sapporo, Hokkaido JAPAN
Kouki Nagamune, PhD, Fukui, Fukui JAPAN
Kazunori Yasuda, MD, PhD, Prof., Sapporo, Hokkaido JAPAN
Department of Sports Medicine and Joint Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, JAPAN
FDA Status Not Applicable
Summary: The present study demonstrated that sufficient intra-operative graft coverage by the remnant tissue in anatomic double-bundle ACL reconstruction significantly improved the pivot shift kinematics at one year postoperatively.
Remnant tissue preservation in ACL reconstruction has theoretical advantages, such as accelerated revascularization and ligamentization, enhanced biological environment for healing, maintenance of the anchor point at the native tibial attachment, and reduction of bone tunnel enlargement. Therefore, several investigators have developed ACL reconstruction techniques with preservation of the remnant tissue. However, there is variability in the degree of the graft coverage with an ACL remnant tissue, and no studies have shown any clinical evidence about the effects of the graft coverage on postoperative knee kinematics. The purpose of this study was to examine correlation between the remnant volume covering the graft and pivot shift kinematics evaluated by the electromagnetic sensor system after anatomic double-bundle ACL reconstruction.
A prospective, in vivo study was conducted with 20 consecutive patients (8 men and 12 women) who underwent ACL reconstruction for unilateral ACL injury. The mean age at the time of surgery was 27.3 years. We performed anatomic double-bundle ACL reconstruction with our original remnant tissue preservation technique. At the end of surgery, we evaluated the degree of coverage of each graft by the remnant tissue using the following scoring system: Each graft mid-substance was divided into three parts; the tibial one-third, the middle one-third, and the femoral one-third. In each part, we provided 3 points when 75% or more of the part was covered by the remnant tissue; when 50-75%, 25-50%, and 0-25% of the part was covered, we gave 2, 1, and 0 points, respectively. We then summed the score of each part for the AM graft, PL graft and both grafts. At one year after surgery, all patients underwent second-look arthroscopy, and the three-dimensional kinematics of bilateral knees during the pivot shift test was evaluated using an electromagnetic sensor (EMS) system under general anesthesia. Peak coupled anterior tibial translation (pCAT) and maximal acceleration of posterior translation (APT) were measured relative to results during a flexion/extension motion in each test. The relationship between the score of remnant coverage and the values of pCAT or APT was assessed using the Pearson's correlation analysis. The significance level was set at p=0.05.
The mean post-operative anterior laxity was 1.1 mm. The Lysholm score averaged 96.1 points. In the IKDC evaluation, 15 patients were graded “A”, and 5 were graded “B”. The side-to-side difference of pCAT correlated with the score for the AM graft (p=0.0193, r=-0.518), PL graft (p=0.0142, r=-0.539), and the total score (p=0.0118, r=-0.551). The side-to-side difference of APT correlated with the score for the PL graft (p=0.0290, r=-0.488) and the total score (p=0.0327, r=-0.479) at one year after surgery.
The present study demonstrated that sufficient intra-operative graft coverage by the remnant tissue in anatomic double-bundle ACL reconstruction significantly improved the pivot shift kinematics at one year postoperatively. Although the quantity of the graft coverage during surgery are strongly affected by that of the remnant ACL tissue and surgical techniques, the sufficient fibrous tissue coverage of the grafts may reduce elongation or failure of the grafts in the graft-remodeling phase, resulting in better knee stability.