ObjectiveTo investigate the effect of the femoral tunnel angle on the femoral tunnel after anterior cruciate ligament (ACL) reconstruction in rabbits. MethodsFifty-four healthy 4-5 months old rabbits (weighing, 1.8-2.3 kg, male or female) were randomly divided into 3 groups (n=18). The ACL reconstruction models of the right knee were established in 3 experimental groups using its Achilles tendons, and the left knee served as the control group. On the coronal position, the angle between the femoral tunnel and the femoral shaft axis was 30°, 45°, and 60°. The level of tumor necrosis factor α (TNF-α) in the synovial fluid at 1, 2, and 4 weeks, the maximum load of the ligament and the rate of bone tunnel enlargement at 4, 8, and 12 weeks were detected. ResultsThe level of TNF-α significantly increased, and the maximum load of the ligament significantly decreased in the 3 experimental groups when compared with ones in the control group (P<0.05), but no significant difference was found among 3 experimental groups (P>0.05). The bone tunnel enlargement was observed in 3 experimental groups at each time point and reached the peak at 4 weeks, but no significant difference was shown among 3 groups (P>0.05). ConclusionThe 30-60° angle between the femoral tunnel and the femoral shaft axis in the coronal position has no significant effect on the femoral tunnel enlargement after ACL reconstruction in rabbits.
ObjectiveTo investigate the best knee flexion angle by analyzing the length and orientation of the femoral tunnel through anteromedial portal (AM) at different flexion angles during anterior cruciate ligament (ACL) reconstruction. MethodsTwelve fresh cadaveric knees were selected to locate the center of ACL femoral footprint through AM using the improved hook slot vernier caliper, and to locate the posterior bone cortex using a diameter 3 mm ball at flexion of 90, 100, 110, 120, and 130°. The femoral tunnel length, standard coronal and sagittal plane angles, and the position relation between exit point and the lateral epicondyle were measured; the tunnel orientation on the anteroposterior and lateral X-ray films was also measured. ResultsWith increasing flexion of the knee, the femoral tunnel length showed a first increasing and then stable tendency; significant difference was found between at flexion of 90°and at flexions of 100, 110, 120, and 130°, and between flexions of 100°and 120°(P<0.05). The femoral tunnel showed a trend of decreasing with coronal angle, whereas gradually increasing with sagittal angle. The knee flexion angle had significant difference either among flexions of 90, 110, and 130°or between flexions of 100°and 120°(P<0.05). The exit point of the femoral tunnel located at the lateral epicondyle of the femur proximal to posterior region at flexion of 90°in all knees, and at flexion of 100°in 7 knees, but it located at the lateral epicondyle of the femur proximal to anterior region at flexion of 110, 120, and 130°in all knees. As the knee flexion angle increasing, the angle between femoral tunnel with the tangent of internal-external femoral condyle on anteroposterior X-ray films showed a trend of decreasing gradually, but a trend of increasing gradually on lateral X-ray films. On the anteroposterior X-ray films, significant differences were found in the angle either among flexions of 90, 110, and 130°or between flexions of 100°and 120°(P<0.05). On the lateral X-ray films, there were significant differences in the angle among flexions of 90, 100, 110, 120, and 130°(P<0.05). ConclusionDuring ACL reconstruction by AM, 110°is the best flexion angle, which can get the ideal femoral tunnel.
ObjectiveTo study the effect of the femoral tunnel position on the knee function recovery after medial patellofemoral ligament (MPFL) reconstruction. MethodsA retrospective analysis was made on the clinical date of 43 cases (43 knees) of recurrent patellar dislocation undergoing MPFL reconstruction and patellofemoral lateral retinaculum lysis between August 2013 and March 2014. There were 12 males and 31 females, aged 19.4 years on average (range, 9-35 years). All patients had trauma history and recurrent dislocations. The results of apprehesion test and J syndrom were positive. The patellar tilt test showed patellofemoral lateral retinaculum was tension. The effectiveness was evaluated using Lysholm knee functional score after operation. The distance from the center of the femoral tunnel to the femoral isometric point was measured on CT three dimensional reconstruction image. Whether the femoral tunnel position was isometric was evaluated. The correlation was analyzed between the distance from the center of the femoral tunnel to the femoral isometric point and Lysholm score. ResultsPrimary healing of incision was obtained in all patients. The patients were followed up 13-18 months (mean, 15 months). No patellar dislocation or subluxation occurred. The result of apprehensive test was negative. At last follow-up, the average Lysholm score was 93.8 (range, 83-100). The average distance from the center of the femoral tunnel to the femoral isometric point was 5.61 mm (range, 2-16 mm). The femoral tunnel position was isometric in 30 cases (69.8%) and non-isometric in 13 cases (30.2%). The distance from the center of the femoral tunnel to the femoral isometric point was negatively correlated with postoperative Lysholm score (r=-0.851, P=0.000). The postoperative Lysholm score was 95.7±2.3 in patients with isometric tunnel and was 89.4±3.5 in patients with non-isometric tunnel, showing significant difference (t=6.951, P=0.000). ConclusionFor patellofemoral joint instability, preparing the femoral isometric tunnel can establish a good foundation for the recovery of the knee function in MPFL reconstruction.