Li Guojun, Zhang Shiqing, Wang Xiao
Department of Orthopaedics, Huaihe Hospital, Henan University, Kaifeng Henan, 475001, PR China.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Jan;24(1):14-6.
Anterior cruciate ligament (ACL) is an important forward stable structure of knees, when its function impaired, the normal mechanical environment of joint will be destroyed. Now, to explore the effect of ACL rupture on the posterior horn of lateral meniscus by measuring biomechanics.
Ten specimens of knee joints (5 left and 5 right sides asymmetrically) were donated voluntarily from 10 normal fresh adult male cadavers, aged 26-35 years with an average of 31.4 years. The straining of lateral meniscus posterior horn in 10 knee joint specimens before and after resection of ACL were tested when the knee joints loaded from 0 to 200 N at a velocity of 0.5 mm per second at 0, 30, 60, and 90 degrees of flexion and recorded at the moment when the load was 200 N, the ratio of straining before and after resection of ACL were counted. All the specimens were anatomied and observed in general so as to find injuries such as deformation and tearing in lateral meniscus after test.
The straining of lateral meniscus posterior horn were as follows: intact ACL group, (-11.70 +/- 0.95) microepsilon at 0 degree flexion, (-14.10 +/- 1.95) microepsilon at 30 degrees flexion, (-20.10 +/- 1.20) microepsilon at 60 degrees flexion, and (-26.50 +/- 1.58) microepsilon at 90 degrees flexion; ACL rupture group, (-6.20 +/- 1.55) microepsilon at 0 degree flexion, (-26.30 +/- 1.89) microepsilon at 30 degrees flexion, (-37.70 +/- 1.64) microepsilon at 60 degrees flexion, and (-46.20 +/- 2.78) microepsilon at 90 degrees flexion. There were significant differences between intact ACL group and ACL rupture group (P < 0.05). The straining ratio of the posterior horn of lateral meniscus rupture ACL to intact ACL were 0.53 +/- 0.12, 1.90 +/- 0.31, 1.88 +/- 0.15, and 1.75 +/- 0.16 at 0, 30, 60, and 90 degrees of flexion. The lateral meniscus were intact in general and no injuries such as deformation and tearing were found.
ACL has a significant biomechanical effect on posterior horn of lateral meniscus. Consequently, the posterior horn of lateral meniscus is overloaded with ACL rupture at 30, 60, and 90 degrees of flexion, and thereby, it will have the high risk of tear.
前交叉韧带（ACL）是膝关节重要的前向稳定结构，其功能受损会破坏关节的正常力学环境。现通过测量生物力学来探讨ACL断裂对外侧半月板后角的影响。
从10具年龄在26 - 35岁、平均31.4岁的正常新鲜成年男性尸体上自愿捐献10个膝关节标本（左右侧各5个，不对称）。在膝关节以每秒0.5毫米的速度从0加载至200牛，屈曲角度分别为0、30、60和90度时，测试10个膝关节标本在ACL切除前后外侧半月板后角的应变情况，并在载荷为200牛时记录，计算ACL切除前后的应变比值。对所有标本进行大体解剖观察，以发现测试后外侧半月板的变形、撕裂等损伤情况。
外侧半月板后角的应变情况如下：ACL完整组，0度屈曲时为（-11.70±0.95）微应变，30度屈曲时为（-14.10±1.95）微应变，60度屈曲时为（-20.10±1.20）微应变，90度屈曲时为（-26.50±1.58）微应变；ACL断裂组，0度屈曲时为（-6.20±1.55）微应变，30度屈曲时为（-26.30±1.89）微应变，60度屈曲时为（-37.70±1.64）微应变，90度屈曲时为（-46.20±2.78）微应变。ACL完整组与ACL断裂组之间存在显著差异（P < 0.05）。外侧半月板后角在ACL断裂时与ACL完整时的应变比值在0、30、60和90度屈曲时分别为0.53±0.12、1.90±0.31、1.88±0.15和1.75±0.16。外侧半月板大体完整，未发现变形、撕裂等损伤。
ACL对外侧半月板后角具有显著的生物力学作用。因此，在30、60和90度屈曲时，ACL断裂会使外侧半月板后角负荷过载，从而有较高的撕裂风险。
