Tse Brian K, Vaughn Zackary D, Lindsey Derek P, Dragoo Jason L
Department of Orthopaedic Surgery, Stanford University, Palo Alto, CA 94063-6342, USA.
Knee. 2012 Aug;19(4):477-81. doi: 10.1016/j.knee.2011.06.013. Epub 2011 Jul 19.
Revision anterior cruciate ligament (ACL) reconstruction often requires a two-stage approach. This study analyzes the biomechanical properties after cyclic loading of a one-stage ACL revision technique using a calcium phosphate bone cement.
Arthroscopic reconstruction of the ACL was performed in 5 matched pairs of fresh-frozen cadaveric knees separated into two groups. The control group underwent a standard reconstruction with a bone-patellar tendon-bone autograft with bioabsorbable interference screw fixation. The experimental group simulated a failed reconstruction by drilling a 12 mm hole and underwent a revision after filling it with a bioabsorbable calcium phosphate bone cement. The specimens were dissected, scanned for bone mineral density, and cyclically loaded on a mechanical testing system (preload of 250 cycles of 5-75 N at 0.5 Hz followed by 10,000 cycles of 20-150 N at 1 Hz). Intact specifmens underwent a load-to-failure protocol of 50mm/min. Ultimate load, stiffness, and modes of failure were recorded. Data was analyzed using paired t-tests.
All specimens completed the mechanical testing protocol. The control group had a mean maximum load of 471.33 N (SD 220.73 N) and the experimental group had 453.54 N (SD 152.36; p=0.84). There were no statistically significant differences in maximum load or stiffness. No correlation between bone mineral density (BMD) and maximum load was found.
Using calcium phosphate filler in a single-stage ACL revision is biomechanically viable. Further testing of long-term incorporation of the ACL graft in an animal model, along with human clinical trials, should be performed before there is clinical acceptance of this technique.
翻修前交叉韧带（ACL）重建通常需要分两阶段进行。本研究分析了使用磷酸钙骨水泥的单阶段ACL翻修技术在循环加载后的生物力学特性。
对5对新鲜冷冻尸体膝关节进行关节镜下ACL重建，分为两组。对照组采用自体骨-髌腱-骨移植并使用生物可吸收干涉螺钉固定进行标准重建。实验组通过钻一个12毫米的孔模拟重建失败，并用生物可吸收磷酸钙骨水泥填充后进行翻修。对标本进行解剖，扫描骨密度，并在机械测试系统上进行循环加载（先以0.5赫兹的频率进行250个周期的5 - 75牛预加载，然后以1赫兹的频率进行10000个周期的20 - 150牛加载）。完整的标本以50毫米/分钟的速度进行破坏载荷试验。记录极限载荷、刚度和破坏模式。使用配对t检验分析数据。
所有标本均完成机械测试方案。对照组的平均最大载荷为471.33牛（标准差220.73牛），实验组为453.54牛（标准差152.36；p = 0.84）。最大载荷或刚度无统计学显著差异。未发现骨密度（BMD）与最大载荷之间存在相关性。
在单阶段ACL翻修中使用磷酸钙填充物在生物力学上是可行的。在该技术被临床接受之前，应在动物模型中对ACL移植物的长期植入情况进行进一步测试，并开展人体临床试验。
