Objective: To investigate the influence of lateral posterior tibial slope (LPTS) on tibial tunnel expansion after anatomical single-bundle anterior cruciate ligament (ACL) reconstruction and the effect of tibial tunnel expansion on knee joint function.
Methods: A clinical data of 52 patients with ACL rupture, who underwent arthroscopic anatomical single-bundle reconstruction between November 2018 and December 2019, was retrospectively analyzed. There were 32 males and 20 females with an average age of 34.3 years (range, 14-64 years). There were 22 cases of left knee and 30 cases of right knee. The time from injury to operation ranged from 7 to 30 days, with an average of 15.9 days. The knee function was evaluated by International Knee Documentation Committee (IKDC) score and Lysholm score before operation and at 3 and 6 months after operation. At 3 and 6 months after operation, the LPTS and the width of exit, middle segment, entrance, and 2 cm from the exit of the articular surface of the tibial tunnel were measured based on MRI. The expansion of tibial tunnel was calculated and graded (degrees 0-3). According to LPTS, the patients were divided into group A (<6.0°), group B (6°-12°), and group C (>12°), and the difference in the expansion of tibial tunnel between groups was compared.
Results: All the 52 patients were followed up 6-12 months (mean, 7.1 months). The IKDC and Lysholm scores at 3 and 6 months after operation were significantly different from those before operation ( P<0.05); and the difference of knee scores between 3 and 6 months after operation was significant ( P<0.05). The tibial tunnel expanded after operation, and the relative expansion at the exit and the middle segment showed significant difference between 3 months and 6 months after operation ( P<0.05). The expansion degree of tibial tunnel was rated as degree 0 in 5 cases, degree 1 in 28 cases, degree 2 in 16 cases, and degree 3 in 3 cases at 3 months after operation, and degree 0 in 5 cases, degree 1 in 20 cases, degree 2 in 25 cases, and degree 3 in 2 cases at 6 months after operation. There was no significant difference in IKDC and Lysholm scores between patients with different expansion degrees of tibial tunnels ( P>0.05). The LPTS of 52 patients ranged from -0.8° to 18.7° (mean, 10.6°); there were 7 cases in group A, 24 cases in group B, and 21 cases in group C. There was no significant difference in age, gender, preoperative IKDC and Lysholm scores, and initial width of tibial tunnel between groups ( P>0.05). There was no significant difference in the relative expansion of tibial tunnel at exit and middle segment between groups at 3 months after operation ( P>0.05), and there was significant difference at 6 months after operation ( P<0.05).
Conclusion: After anatomical single-bundle reconstruction of ACL, the tibial tunnel would expand to some extent in a short time. LPTS had a significant effect on tibial tunnel expansion, and the larger the angle was, the more obvious the expansion of the proximal tibial tunnel was. However, early knee function is not affected by tibial tunnel expansion.
目的: 探讨胫骨外侧平台后倾角（lateral posterior tibial slope，LPTS）对单束解剖重建前交叉韧带（anterior cruciate ligament，ACL）术后胫骨隧道扩张影响，以及隧道扩张对膝关节功能的影响。.
方法: 回顾分析 2018 年 11 月—2019 年 12 月 52 例因 ACL 断裂行关节镜下单束解剖重建患者的临床资料。男 32 例，女 20 例；年龄 14～64 岁，平均 34.3 岁。左膝 22 例，右膝 30 例。受伤至手术时间 7～30 d，平均 15.9 d。术前及术后 3、6 个月采用国际膝关节文献委员会（IKDC）评分及 Lysholm 评分评价膝关节功能。术后 3、6 个月基于 MRI 测量 LPTS 及胫骨隧道出口、中段、入口、距关节面出口 2 cm 处宽度；计算隧道绝对及相对扩张量，并根据绝对扩张量对隧道扩张程度进行分度（0～3 度）比较。同时将患者根据 LPTS 分为<6.0° 组（A 组）、6°～12° 组（B 组）、>12° 组（C 组），比较组间胫骨隧道扩张程度差异。.
结果: 52 例患者术后均获随访，随访时间 6～12 个月，平均 7.1 个月。术后 3、6 个月 IKDC 评分和 Lysholm 评分与术前比较，术后 3、6 个月间比较，差异均有统计学意义（ P<0.05）。术后胫骨隧道均发生扩张，其中出口和中段相对扩张量术后 3、6 个月间差异有统计学意义（ P<0.05）。术后 3 个月胫骨隧道扩张程度达 0 度 5 例、1 度 28 例、2 度 16 例、3 度 3 例，6 个月时分别为 5、20、25、2 例。不同胫骨隧道扩张程度患者术后同时间点 IKDC 评分和 Lysholm 评分比较，差异均无统计学意义（ P>0.05）。52 例患者 LPTS 为−0.8°～18.7°，平均 10.6°；其中 A 组 7 例、B 组 24 例、C 组 21 例。3 组患者年龄、性别、术前 IKDC 评分及 Lysholm 评分、胫骨隧道初始宽度比较，差异均无统计学意义（ P>0.05）。A、B、C 组胫骨隧道出口和中段相对扩张量比较，术后 3 个月时差异均无统计学意义（ P>0.05），6 个月时差异均有统计学意义（ P<0.05）。.
结论: 单束解剖重建 ACL 术后，胫骨隧道在早期均会发生一定程度扩张。LPTS 对胫骨隧道扩张有显著影响，该角度越大，胫骨隧道近端扩张越明显，但是患者早期膝关节功能未受隧道扩张影响。.
Keywords: Lateral posterior tibial slope; anterior cruciate ligament; bone tunnel expansion; knee function; ligament reconstrcution.