Miho J. Tanaka, Regeneration Orthopedics, 6 McBride & Son Center Drive, Suite 204, St Louis, MO 63005.
Am J Sports Med. 2013 Oct;41(10):2347-52. doi: 10.1177/0363546513498995. Epub 2013 Aug 8.
Abnormal anterior-posterior and rotational motion secondary to anterior cruciate ligament (ACL) insufficiency is typically described in terms of dynamic laxity. An original description of the abnormal tibiofemoral relationship in the setting of ACL insufficiency has highlighted the presence of a fixed anterior tibial subluxation in this population of failed ACL reconstruction (ACLR); however, no study has quantified the degree of tibial subluxation in both the medial and lateral compartments.
To measure and compare the amount of anterior tibial subluxation among various states of ACL competency, including (1) intact ACL, (2) acute ACL disruption, and (3) failed ACLR (ie, patients requiring revision ACLR). We hypothesized that anterior tibial displacement would be greater in the lateral compartment and in cases of failed ACLR compared with intact and acute ACL injured states.
Cross-sectional study; Level of evidence, 3.
Using sagittal magnetic resonance imaging (MRI) and a standardized measurement technique, we determined the amount of anterior tibial subluxation relative to a constant posterior condylar reference point. Measurements were performed in both the medial and the lateral compartments and were compared with 1-way analysis of variance. The presence of meniscal tears along with meniscal volume loss and chondral damage was correlated with the amount of subluxation in each group.
Compared with the intact ACL state, the medial tibial plateau was positioned more anteriorly relative to the femur in both acute ACL injured knees (mean 1.0 mm) and those that failed ACLR (mean 1.8 mm) (P = .072). In the lateral compartment, there was 0.8 mm of mean anterior tibial displacement after acute ACL injury and 3.9 mm of mean anterior subluxation in patients who failed ACLR (P < .001). Mean anterior displacement of the lateral plateau in patients who failed ACLR was almost 5 times greater than the amount observed in patients with acute ACL injuries. There was no correlation between meniscal/chondral injury and the amount of subluxation.
Patients who require revision ACLR have an abnormal tibiofemoral relationship noted on MRI that is most pronounced in the lateral compartment and should be taken into account during revision surgery. These observations may explain the suboptimal clinical results seen in some patients who undergo revision ACLR.
前交叉韧带（ACL）功能不全导致的异常前后和旋转运动通常根据动态松弛来描述。ACL 功能不全患者的异常胫股关节关系的原始描述强调了 ACL 重建失败（ACLR）人群中存在固定的胫骨前侧半脱位；然而，尚无研究定量测量 ACL 功能完好、急性 ACL 损伤和 ACLR 失败（即需要接受 ACLR 翻修的患者）这三种状态下的胫骨前侧半脱位程度。
测量并比较 ACL 不同功能状态下的胫骨前侧半脱位程度，包括（1）ACL 完好，（2）急性 ACL 撕裂，和（3）ACLR 失败（即，需要接受 ACLR 翻修的患者）。我们假设与 ACL 完好和急性 ACL 损伤状态相比，胫骨前侧位移在外侧间室和 ACLR 失败病例中会更大。
横断面研究；证据等级，3 级。
使用矢状面磁共振成像（MRI）和标准化测量技术，我们确定了相对于恒定后髁参照点的胫骨前侧半脱位程度。在内外侧间室均进行了测量，并进行了单因素方差分析。将半月板撕裂以及半月板体积损失和软骨损伤与每组的半脱位程度进行了相关性分析。
与 ACL 完好状态相比，急性 ACL 损伤膝关节（平均 1.0 mm）和 ACLR 失败膝关节（平均 1.8 mm）的内侧胫骨平台相对于股骨更靠前（P =.072）。在外侧间室中，急性 ACL 损伤后胫骨前侧平均位移为 0.8 mm，而 ACLR 失败患者的平均前侧半脱位为 3.9 mm（P <.001）。ACLR 失败患者的外侧胫骨平台的平均前侧位移几乎是急性 ACL 损伤患者的 5 倍。半月板/软骨损伤与半脱位程度之间无相关性。
需要接受 ACLR 翻修的患者在 MRI 上存在异常的胫股关节关系，在外侧间室中最为明显，在翻修手术中应予以考虑。这些观察结果可能解释了一些接受 ACLR 翻修的患者临床结果不理想的原因。
