胫骨平台后倾角对前十字韧带重建术后膝关节前向稳定性的影响

目的 评估胫骨平台后倾角与前十字韧带重建术后膝关节前向稳定性的关系.方法 选取2010年10月至2011年6月收治的年龄45岁以下单侧前十字韧带完全断裂行前十字韧带重建的40例患者进行回顾性研究.男28例,女12例；年龄14～44岁,中位年龄22岁.随访时间24-37个月,平均27.5个月.依据术前MRI测量的胫骨内侧和外侧平台后倾角分别将患者分为三组:后倾角＜3°组,后倾角3°～5°组,后倾角≥5°组.以末次随访时KT-1000侧侧差值评估膝关节的前向稳定性,＞5 mm为移植物失效,计算失效率,比较三组移植物失效率的差异.采用Pearson相关检验确定胫骨平台后倾角与KT-1000侧侧差值的相关性,利用受试者工作特征曲线和逻辑斯蒂回归计算内侧和外侧平台后倾角致移植物失效的阈值及其敏感度、特异度.结果 术前MRI测量内侧后倾角4.6°±2.8°,外侧后倾角4.2°±3.4°.内、外侧后倾角≥5°组的移植物失效率均高于后倾角＜3°组,差异有统计学意义.内侧、外侧平台后倾角均与KT-1000侧侧差值呈线性相关(r=0.43,P=0.01；r=0.36,P=0.02).内侧或外侧平台后倾角每增加1°,移植物失效的风险分别增加1.76倍和1.68倍.当内侧平台后倾角＞5.6°或外侧平台后倾角＞3.8°时,移植物失效的风险显著增加.结论 胫骨平台后倾角与前十字韧带重建术后膝关节前向稳定性呈正相关.增大的平台后倾角是术后移植物失效的高危因素,内侧和外侧阈值分别为5.6°和3.8°.

Effect of posterior tibial slope on anterior knee stability after anterior cruciate ligament reconstruction

Objective To assess the relationship between posterior tibial slope (PTS) and anterior knee stability after anterior cruciate ligament (ACL) reconstruction. Methods From October 2010 to June 2011, 40 patients underwent ACL reconstruction for unilateral ACL rupture in our hospital. There were 28 males and 12 females, aged from 14 to 44 years (median, 22 years). All patients were followed up for 24 to 37 months (average, 27.5 months). According to PTS value measured by MRI, the patients were divided into 3 groups: PTS<3° group, 3°≤PTS<5° group, and PTS≥5° group. The KT-1000 side-to-side difference at final follow-up was used to evaluate the anterior knee stability, and the difference more than 5 mm was defined as graft failure. The comparison of failure rate between groups was firstly conducted, then the Pearson' correlation analysis was used to test the correlation between PTS and KT-1000 side-to-side difference. Finally, the threshold of medial and lateral PTS leading to graft failure and its sensitivity and specificity were calculated using receiver operating characteristic curve and logistic regression. Results Before operation, the average medial PTS was 4.6°±2.8°, and the average lateral PTS was 4.2°±3.4°. The failure rate in PTS≥5° group were significantly higher than that in PTS<3° group, and the difference was significant. Both medial (r=0.43, P=0.01) and lateral PTS (r=0.36, P=0.02) significantly correlated with the KT-1000 side-to-side difference. For each additional 1° of medial and lateral PTS, the risk of graft failure increased 1.76-fold and 1.68-fold, respectively. When medial PTS was more than 5.6° or lateral PTS was more than 3.8° , the risk of graft failure increased significantly. Conclusion There is a positive correlation between PTS and anterior knee stability. The enlarged PTS is a high risk factor for graft failure, and the threshold of medial and lateral PTS is 5.6° and 3.8°, respectively.