Sports Medicine and Shoulder Service, New York, New York 10021, USA.
Arthroscopy. 2010 Mar;26(3):342-50. doi: 10.1016/j.arthro.2009.12.006.
To compare the obliquity and length of femoral tunnels prepared with transtibial versus anteromedial portal drilling for anterior cruciate ligament (ACL) reconstruction and identify potential risks associated with the anteromedial portal reaming technique.
We used 18 human cadaveric knees (9 matched pairs) without ACL injury or pre-existing arthritis for the study. Femoral tunnels for ACL reconstruction were prepared by either a transtibial (n = 6) or anteromedial portal (n = 12) technique. For the anteromedial portal technique, a guidewire was advanced through the medial portal in varying degrees of knee flexion (100 degrees [n = 4], 110 degrees [n = 4], or 120 degrees [n = 4]) as measured with a goniometer. By use of a 6-mm femoral offset guide, two 6-mm femoral tunnels were reamed with the guide placed (1) as far posterior and lateral in the notch as possible and (2) as far medial and vertical in the notch as possible to define the range of maximal and minimal achievable coronal obliquity for each technique. All knees were imaged with high-resolution, 3-dimensional fluoroscopy to define (1) coronal tunnel obliquity relative to the lateral tibial plateau, (2) sagittal tunnel obliquity relative to the long axis of the femur, (3) intraosseous tunnel length, and (4) the presence of posterior cortical wall blowout. Data analysis was performed with a paired t-test and repeated-measures analysis of variance, with P < .05 defined as significant.
Preparation of a vertical tunnel was possible with both transtibial and anteromedial portal drilling. The maximal achievable coronal obliquity, however, was significantly better with an anteromedial portal compared with transtibial drilling. However, 7 of 36 tunnels (19.4%) showed violation of the posterior tunnel wall, and all of these cases occurred with the anteromedial portal drilling technique. In addition, 1 of 6 oblique femoral tunnels (16.7%) drilled with the transtibial technique and 5 of 12 oblique femoral tunnels (41.7%) drilled with the anteromedial portal had an intraosseous length less than 25 mm. Increasing knee flexion with anteromedial portal drilling was associated with a significant reduction in tunnel length, increase in coronal obliquity, increase in sagittal obliquity, and increased risk of posterior wall blowout (P < .05).
The anteromedial portal technique allows for slightly greater femoral tunnel obliquity compared with transtibial drilling. However, there is a substantially increased risk of critically short tunnels (<25 mm) and posterior tunnel wall blowout when a conventional offset guide is used. Increasing knee flexion with anteromedial portal drilling allows for greater coronal obliquity of the femoral tunnel but is accompanied by a greater risk of critically short tunnels and posterior wall compromise.
Our findings provide insight into the potential risks and advantages of a transtibial versus an anteromedial femoral tunnel drilling technique in ACL reconstruction.
比较经胫骨与前内侧入路钻孔制备前交叉韧带（ACL）重建股骨隧道的倾斜度和长度，并确定前内侧入路扩孔技术相关的潜在风险。
我们使用了 18 个人体尸体膝关节（9 对匹配），这些膝关节没有 ACL 损伤或预先存在的关节炎。ACL 重建的股骨隧道通过经胫骨（n = 6）或前内侧入路（n = 12）技术制备。对于前内侧入路技术，导丝通过内侧入路以不同程度的膝关节弯曲（通过量角器测量为 100 度[n = 4]、110 度[n = 4]或 120 度[n = 4]）推进。使用 6 毫米股骨偏移导板，用导板尽可能地在切迹的后外侧（1）和尽可能地在切迹的内侧和垂直方向（2）制备两个 6 毫米股骨隧道，以定义每种技术可实现的最大和最小冠状倾斜度范围。所有膝关节均通过高分辨率、3 维荧光透视成像来定义（1）相对于外侧胫骨平台的冠状隧道倾斜度，（2）相对于股骨长轴的矢状隧道倾斜度，（3）骨内隧道长度，以及（4）是否存在后皮质壁爆裂。数据分析采用配对 t 检验和重复测量方差分析，以 P <.05 定义为有统计学意义。
胫骨与前内侧入路钻孔均能制备垂直隧道。然而，与经胫骨钻孔相比，前内侧入路可获得更好的最大冠状倾斜度。然而，36 个隧道中有 7 个（19.4%）存在后隧道壁破裂，所有这些情况均发生在前内侧入路钻孔技术中。此外，胫骨经皮入路钻孔的 1 个（16.7%）斜形股骨隧道和前内侧入路钻孔的 12 个（41.7%）斜形股骨隧道中有 5 个骨内长度小于 25 毫米。随着前内侧入路钻孔时膝关节弯曲度的增加，隧道长度显著缩短，冠状倾斜度增加，矢状倾斜度增加，后壁爆裂的风险增加（P <.05）。
与经胫骨钻孔相比，前内侧入路技术可使股骨隧道的倾斜度略有增加。然而，当使用常规偏移导板时，隧道明显变短（<25 毫米）和后壁爆裂的风险显著增加。随着前内侧入路钻孔时膝关节弯曲度的增加，股骨隧道的冠状倾斜度增加，但同时隧道明显变短和后壁受损的风险也增加。
我们的研究结果提供了经胫骨与前内侧股骨隧道钻孔技术在 ACL 重建中的潜在风险和优势的深入了解。
