David Bahlau1, Philippe Clavert2, Henri Favreau1, Matthieu Ollivier3, Sébastien Lustig4, François Bonnomet1, Matthieu Ehlinger5. 1. Service de chirurgie orthopédique et de traumatologie, hôpital de Hautepierre, hôpitaux universitaires de Strasbourg, 1, avenue Molière, 67098 Strasbourg cedex, France. 2. Service de chirurgie du membre supérieur, centre de chirurgie orthopédique et de la main, hôpitaux universitaires de Strasbourg, 10, avenue Achille-Baumann, 67400 Illkirch, France; Institut d'anatomie normale, faculté de médecine de Strasbourg, 4, rue Kirschleger, 67000 Strasbourg, France; Laboratoire ICube, CNRS UMR 7357, 30, boulevard Sébastien-Brant, 67400 Ilkirch, France. 3. Service de chirurgie orthopédique, hôpital Sainte-Marguerite, AP-HM, 13009 Marseille, France. 4. Département de chirurgie orthopédique, centre Albert-Trillat, hôpital de la Croix-Rousse, 103, boulevard de la Croix-Rousse, 69004 Lyon, France. 5. Service de chirurgie orthopédique et de traumatologie, hôpital de Hautepierre, hôpitaux universitaires de Strasbourg, 1, avenue Molière, 67098 Strasbourg cedex, France; Laboratoire ICube, CNRS UMR 7357, 30, boulevard Sébastien-Brant, 67400 Ilkirch, France. Electronic address: Matthieu.ehlinger@chru-strasbourg.fr.
Abstract
INTRODUCTION: The best fixation method for an anterior cruciate ligament (ACL) graft is debated. The tibial fixation of tendon grafts is the principal weak point for mechanical and anatomical reasons. Preserving the tibial insertion for hamstring grafts during ACL reconstruction make provide a mechanical benefit. The aim of this study was to compare the strength at the tibial tunnel of a hamstring graft with intact tibial insertion without a screw, to that of a graft with intact tibial insertion and screw fixation, and to that of a free graft with screw fixation. We hypothesized that preserving the graft's tibial insertion increases the maximum resistance of the tibial fixation relative to a free graft. MATERIALS AND METHODS: Five pairs of knees (10 specimens) from frozen human donors were used. The tendons of the semitendinosus and gracilis were prepared as a four-strand graft while preserving their tibial insertion. The graft was passed through the tibial tunnel using standard instrumentation and the usual landmarks. Three conditions were tested: group 1 - graft with intact tibial insertion without interference screw; group 2 - graft with intact tibial insertion and interference screw; group 3 - knees from group 1 in which the tendons were detached (free graft) after the first test and fixed with an interference screw in the tibial tunnel. The screw diameter was chosen based on the graft diameter. The specimens were tested in traction using a materials testing system (Instron® 8500 PLUS) in the axis of the tunnel. The main outcome measure was the maximum load at failure (N). The secondary outcome measure was the stiffness. The groups were compared using the Friedman test and the Nemenyi post-hoc test with a 5% threshold. RESULTS: The load at failure was 33% higher in group 1 than group 3 (89.2N vs. 67.2N, p>0.05). The load at failure of group 2 was 25% higher than group 1 (111.2N vs. 89.2N, p>0.05) and 65% higher than group 3 (111.2N vs. 67.2N p=0.005). There were no differences in stiffness between groups 1 and 2 (p=1). DISCUSSION: Our hypothesis was confirmed-preserving the tibial insertion of hamstring tendons intended for ACL reconstruction increases the maximum load to failure at the tibial tunnel. Under these experimental conditions it seems that adding a screw increases the pullout strength of the graft by +25% in absolute terms; however this difference was not statistically significant. LEVEL OF EVIDENCE: III, controlled laboratory study.
INTRODUCTION: The best fixation method for an anterior cruciate ligament (ACL) graft is debated. The tibial fixation of tendon grafts is the principal weak point for mechanical and anatomical reasons. Preserving the tibial insertion for hamstring grafts during ACL reconstruction make provide a mechanical benefit. The aim of this study was to compare the strength at the tibial tunnel of a hamstring graft with intact tibial insertion without a screw, to that of a graft with intact tibial insertion and screw fixation, and to that of a free graft with screw fixation. We hypothesized that preserving the graft's tibial insertion increases the maximum resistance of the tibial fixation relative to a free graft. MATERIALS AND METHODS: Five pairs of knees (10 specimens) from frozen human donors were used. The tendons of the semitendinosus and gracilis were prepared as a four-strand graft while preserving their tibial insertion. The graft was passed through the tibial tunnel using standard instrumentation and the usual landmarks. Three conditions were tested: group 1 - graft with intact tibial insertion without interference screw; group 2 - graft with intact tibial insertion and interference screw; group 3 - knees from group 1 in which the tendons were detached (free graft) after the first test and fixed with an interference screw in the tibial tunnel. The screw diameter was chosen based on the graft diameter. The specimens were tested in traction using a materials testing system (Instron® 8500 PLUS) in the axis of the tunnel. The main outcome measure was the maximum load at failure (N). The secondary outcome measure was the stiffness. The groups were compared using the Friedman test and the Nemenyi post-hoc test with a 5% threshold. RESULTS: The load at failure was 33% higher in group 1 than group 3 (89.2N vs. 67.2N, p>0.05). The load at failure of group 2 was 25% higher than group 1 (111.2N vs. 89.2N, p>0.05) and 65% higher than group 3 (111.2N vs. 67.2N p=0.005). There were no differences in stiffness between groups 1 and 2 (p=1). DISCUSSION: Our hypothesis was confirmed-preserving the tibial insertion of hamstring tendons intended for ACL reconstruction increases the maximum load to failure at the tibial tunnel. Under these experimental conditions it seems that adding a screw increases the pullout strength of the graft by +25% in absolute terms; however this difference was not statistically significant. LEVEL OF EVIDENCE: III, controlled laboratory study.
Authors: David Bahlau; Henri Favreau; David Eichler; Sébastien Lustig; François Bonnomet; Matthieu Ehlinger Journal: Int Orthop Date: 2019-08-24 Impact factor: 3.075
Authors: Anderson de Aquino Santos; Mario Carneiro-Filho; Roberto Freire da Mota E Albuquerque; João Paulo Freire Martins de Moura; Carlos Eduardo Franciozi; Marcus Vinícius Malheiros Luzo Journal: Clinics (Sao Paulo) Date: 2020-04-30 Impact factor: 2.365