Handy Michael H, Blessey Peter B, Kline Alex J, Miller Mark D
Department of Orthopaedics, University of Virginia Health System, Charlottesville, Virginia 22908, USA.
Arthroscopy. 2005 Jun;21(6):711-4. doi: 10.1016/j.arthro.2005.03.011.
In posterior cruciate ligament reconstruction, the tibial tunnel/graft angle (or killer turn) has been implicated in graft failure when using transtibial tunnel placement. The graft/femoral tunnel angle (or critical corner) can also contribute to shear stress and early graft failure. The purpose of this study was to quantitate the killer turn angle in flexion and extension and to compare critical corner angles using outside-in and inside-out techniques for femoral tunnel placement.
A cadaveric, biomechanical comparison.
One transtibial tunnel and 2 femoral tunnels were marked with guidewires in 9 fresh-frozen cadaveric knees. The killer turn and the 2 critical corner angles were measured at 90 degrees of flexion and full extension on fluoroscopic images. Results were analyzed using a Student t test with paired data.
The average killer turn was 70 degrees +/- 12 degrees and 78 degrees +/- 7 degrees in flexion and extension, respectively. Knee extension significantly increased the killer turn angle (P = .048). The average critical corner was 50 degrees +/- 16 degrees and -14 degrees +/- 18 degrees with the outside-in technique versus 87 degrees +/- 8 degrees and 27 degrees +/- 14 degrees with the inside-out technique in flexion and extension, respectively. The inside-out technique significantly increased the critical corner in flexion (P = .00007) and extension (P = .00005). At 90 degrees of flexion, the critical corner angle using the inside-out technique significantly exceeded the killer turn angle (P = .003).
We recommend the outside-in technique for femoral tunnel placement to reduce the graft/femoral tunnel angle. Using the inside-out technique can significantly sharpen the critical corner, causing it to exceed the killer turn in flexion.
This study indicates that significantly lower graft/femoral tunnel angles can be obtained when using the outside-in technique for femoral tunnel placement when compared with the inside-out technique. This may translate to lower rates of graft failure in clinical application, although further clinical studies are needed.
在后交叉韧带重建术中，使用经胫骨隧道置入时，胫骨隧道/移植物角度（或致命转折）与移植物失败有关。移植物/股骨隧道角度（或关键拐角）也会导致剪切应力和早期移植物失败。本研究的目的是量化屈伸时的致命转折角度，并比较使用由外向内和由内向外技术进行股骨隧道置入时的关键拐角角度。
尸体生物力学比较。
在9个新鲜冷冻尸体膝关节中用导丝标记1个经胫骨隧道和2个股骨隧道。在透视图像上于90°屈曲和完全伸展时测量致命转折和2个关键拐角角度。使用配对数据的学生t检验分析结果。
屈伸时平均致命转折分别为70°±12°和78°±7°。膝关节伸展显著增加致命转折角度（P = 0.048）。由外向内技术在屈伸时平均关键拐角分别为50°±16°和 -14°±18°，而由内向外技术在屈伸时分别为87°±8°和27°±14°。由内向外技术在屈曲（P = 0.00007）和伸展（P = 0.00005）时显著增加关键拐角。在90°屈曲时，使用由内向外技术的关键拐角角度显著超过致命转折角度（P = 0.003）。
我们推荐使用由外向内技术进行股骨隧道置入以减小移植物/股骨隧道角度。使用由内向外技术可显著锐化关键拐角，使其在屈曲时超过致命转折。
本研究表明，与由内向外技术相比，使用由外向内技术进行股骨隧道置入时可获得显著更低的移植物/股骨隧道角度。这在临床应用中可能转化为更低的移植物失败率，尽管还需要进一步的临床研究。
