Comparison of femoral fixation methods for anterior cruciate ligament reconstruction with patellar tendon graft: a mechanical analysis in porcine knees.

The aim of the present study was to evaluate the structural properties of femur-patellar tendon graft complex in anterior cruciate ligament (ACL) reconstruction using different femoral fixation devices. Type of study is biomechanical testing. An ACL reconstruction was performed on 40 cadaver porcine knees, using patellar tendon (PT) graft. Specimens were divided into four groups according to the femoral fixation: interference absorbable screw (Group A), metallic setscrew (Group B), absorbable pins (Group C), and a combination of metallic setscrew and pin (Group D). Other ten knees were used as controls. On each sample, a cyclic loading test, then a load-to-failure test were performed. Elongation after 1,000 loading cycles, ultimate failure load, yield load, stiffness, deformation at the yield point, and mode of failure were recorded. Kruskal-Wallis test and Tukey test were used to compare the differences between groups. The lowest mean elongation after 1,000 load cycles was observed for Group B (1.7 +/- 1.4 mm) and D (1.2 +/- 0.3 mm). Ultimate failure load of Group D (1,021.8 +/- 199.4 N) was comparable with that of normal ACL (1,091.2 +/- 193.3 N) and PT graft (1,140.6 +/- 285.7 N). All other groups were lower than the controls. For mean stiffness, all the groups, excepting for Group D (172.8 +/- 40.4 N/mm), were significantly lower than PT control group (216 +/- 78.4 N/mm). Mode of failure was graft pullout for Groups A and B, distal pin breakage for Group C, and midsubstance graft rupture in 80% of the cases for Group D. Only combined compression and suspension fixation did not show significantly different structural properties in comparison with normal ACL and PT graft. Furthermore, it showed no risk of graft pullout or hardware breakdown in comparison with other fixation devices.

Comparison between different femoral fixation devices for ACL reconstruction with doubled hamstring tendon graft: a biomechanical analysis.

PURPOSE: The aim of the present study was to compare the mechanical behavior of some devices used for femoral fixation of doubled hamstring tendon graft in anterior cruciate ligament (ACL) reconstruction when included in a graft fixation complex (GFC). METHODS: An ACL reconstruction was performed on 90 porcine knees. The graft used was the doubled lateral extensor of toes (DLET). Nine different femoral fixation devices were tested and classified according to their fixation mechanism: compression (Bioscrew and RCI screw); expansion (Rigidfix); cortical suspension (Ligament Anchor, EndoButton-CL, and Swing Bridge); cancellous suspension (Linx-HT); and cortical-cancellous suspension (Transfix and Bio-Transfix). All GFC were subjected to a cyclic loading test, then to a load-to-failure test. Graft elongation after 1,000 load cycles, failure load, and stiffness were calculated for each device. RESULTS: Regarding graft elongation, Bioscrew and RCI screws showed the highest mean values. All the other GFC showed no significant differences between them when delta elongation (elongation(1,000 cycles) - elongation(20 cycles)) was considered. For failure load, the highest mean values were observed for Bio-Transfix, Transfix, and Swing Bridge; a homogeneous subset with the lowest mean values was formed by Ligament Anchor, RCI screw, Bioscrew, and Linx-HT. For stiffness, the greatest values were observed for Bio-Transfix, Transfix, and Swing Bridge; all other groups showed no significant differences between them. CONCLUSIONS: Cortical-cancellous suspension fixation seemed to offer the best and most predictable results in terms of elongation, fixation strength, and stiffness. For both compression and suspension, the weakest fixation was attained with cancellous fixation devices. Cortical suspension devices showed a greatly variable mechanical behavior, according to their design. CLINICAL RELEVANCE: Transcondylar devices offer the best structural properties for femoral fixation of doubled hamstring tendon graft in ACL reconstruction.

Evaluation of bone plug and soft tissue anterior cruciate ligament graft fixation over time using transverse femoral fixation in a sheep model.

PURPOSE: To evaluate the mechanical role of bone-anterior cruciate ligament (ACL) graft junction in comparison with primary fixation of the graft. TYPE OF STUDY: Ex vivo controlled biomechanical study. METHODS: An ACL reconstruction was performed on 2 groups of 40 sheep each. The ACL graft was patellar tendon in group 1, and free tendon in group 2. Load-to-failure tests were performed at 1, 2, 3, and 6 months. Each group was divided into 2 subgroups: In subgroup A the femoral fixation devices were removed before testing and in subgroup B they were left in place. RESULTS: At 1 month, structural properties of subgroup 2A were significantly lower than other subgroups. Until the third month, structural properties of each subgroup were significantly lower than normal ACL. Grafts always failed at midsubstance, except for subgroup 2A at 1 month, which pulled out of the femoral tunnel. CONCLUSIONS: Bone plug incorporation was stronger than graft strength at 1 month whereas soft tissue tendon incorporation was not stronger than graft until 2 months. At 3 months, both groups failed at approximately 30% of the native ACL strength, and at 6 months, both groups were nearly equal in terms of load to failure and stiffness. CLINICAL RELEVANCE: High fixation strength and stiffness of ACL graft does not allow earlier return to sports activities.

Mechanical analysis of fixation methods for anterior cruciate ligament reconstruction with hamstring tendon graft. An experimental study in sheep knees.

This study evaluates the structural properties of the femur-anterior cruciate ligament (ACL) graft-tibia complex, comparing different graft fixation techniques in sheep knees. Four fixation devices were tested both for femoral fixation (Transfix, absorbable screw, RCI screw and Linx-HT) and tibial fixation (bone plug with metal screw, absorbable screw with staple, RCI screw and cancellous screw with spiked washer). The graft used for ACL reconstruction was fresh ovine doubled Achilles tendon (DAT). Femurs and tibias were tested separately. Two mechanical test series were performed on the specimens: a load-to-failure test and a cyclic loading test. On the femoral side, transcondylar screw showed the greatest fixation strength and stiffness and the lowest elongation at cyclic loading. Tibial fixation complexes seemed to have poorer structural properties in comparison to femoral fixation. Among the tibial fixation devices, absorbable screw with staple fixation showed the greatest strength and stiffness. Spiked washer fixation showed the greatest elongation under cyclic loading.

Anterior cruciate ligament reconstruction with doubled semitendinosus and gracilis tendon graft in rugby players.

The purpose of this study was to evaluate prospectively the results of anterior cruciate ligament (ACL) reconstruction with doubled hamstring tendon graft in a selected group of 18 rugby players. The graft was fixed with a transcondylar screw (Transfix) on the femur, and with an absorbable interference screw and a metallic staple on the tibia. All the patients followed the same rehabilitation program. Return to sports activities was allowed after 6 months. Follow-up was 2 years in all cases. The athletic level of the patients was rated according to the Tegner scoring system. Clinical results were evaluated using the International Knee Documentation Committee (IKDC) scoring system. Furthermore, an instrumented evaluation of the anterior laxity with a KT-1000 arthrometer, and an isokinetic evaluation were performed 6 and 24 months after surgery. The Tegner mean score at follow-up (8.2) was similar to that prior to injury (8.3). IKDC overall results were normal in ten cases (55.6%), nearly normal in six cases (33.3%), and abnormal in two cases (11.1%). Side-to-side difference of anterior laxity measured with KT-1000 at 6 and 24 months did not show an impairment of knee stability with time. Isokinetic evaluation showed a significant improvement on peak torque both in extension and flexion on comparison between 6- and 24-month measurements. The results reported in this study showed that the use of doubled hamstring tendon graft for ACL reconstruction in athletes that were at risk for high-energy traumas to the knees, such as rugby players, gave normal or nearly normal results in about 90% of the cases. Recovery of muscle strength was almost complete 2 years after surgery, and there was no impairment of knee stability with time.

Arthroscopic versus open treatment of Bankart lesion of the shoulder: a prospective randomized study.

PURPOSE: The purpose of this study was to compare the results of arthroscopic and open repair of isolated Bankart lesions of the shoulder using metallic suture anchors. TYPE OF STUDY: Prospective randomized clinical study. METHODS: Sixty patients with traumatic anterior shoulder instability underwent a surgical repair of an isolated Bankart lesion. The patients were divided into 2 groups of 30 patients each. In group 1, an arthroscopic repair was performed, and in group 2, an open procedure was performed. The groups were homogeneous for gender, age, dominance, number of dislocations, time elapsed between first dislocation and surgery, and pathologic findings. In all cases of both groups, the lesion was repaired using metallic suture anchors carrying nonabsorbable braided sutures. Postoperative rehabilitation was the same for the 2 groups. Two years' follow-up evaluation included Constant and Rowe shoulder scores. Statistical analysis of data was performed using an unpaired t test (significance for P <.05). RESULTS: No recurrence of dislocation of the involved shoulder has been reported in either group. Follow-up Constant and Rowe scores of the 2 groups were not significantly different. The only significant difference seen between the 2 groups was for range of motion evaluation with the Constant score. The mean value for group 1 (39.6 +/- 0.8) was significantly greater (P =.017) than that for group 2 (37.8 +/- 2.0). CONCLUSIONS: Arthroscopic repair with suture anchors is an effective surgical technique for the treatment of an isolated Bankart lesion. Open repair does not offer a significantly better 2-year result in terms of stability, and furthermore, can negatively affect the recovery of full range of motion of the shoulder. LEVEL OF EVIDENCE: Level I.