Orthopaedic Bioengineering Laboratory, Newton-Wellesley Hospital/Harvard Medical School, Newton, Massachusetts, U.S.A.; Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.; Orthopaedic Surgery, Leiden University Medical Center, Leiden, The Netherlands.
Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.
Arthroscopy. 2018 Apr;34(4):1094-1103. doi: 10.1016/j.arthro.2017.10.042. Epub 2018 Mar 1.
To evaluate the in vivo anisometry and strain of theoretical anterior cruciate ligament (ACL) grafts in the healthy knee using various socket locations on both the femur and tibia.
Eighteen healthy knees were imaged using magnetic resonance imaging and dual fluoroscopic imaging techniques during a step-up and sit-to-stand motion. The anisometry of the medial aspect of the lateral femoral condyle was mapped using 144 theoretical socket positions connected to an anteromedial, central, and posterolateral attachment site on the tibia. The 3-dimensional wrapping paths of each theoretical graft were measured. Comparisons were made between the anatomic, over the top (OTT), and most-isometric (isometric) femoral socket locations, as well as between tibial insertions.
The area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. The most isometric attachment site was found midway on the Blumensaat line with approximately 2% and 6% strain during the step-up and sit-to-stand motion, respectively. Posterior femoral attachments resulted in decreased graft lengths with increasing flexion angles, whereas anterodistal attachments yielded increased lengths with increasing flexion angles. The anisometry of the anatomic, OTT and isometric grafts varied between tibial insertions (P < .001). The anatomic graft was significantly more anisometric than the OTT and isometric graft at deeper flexion angles (P < .001).
An area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. ACL reconstruction at the isometric and OTT location resulted in nonanatomic graft behavior, which could overconstrain the knee at deeper flexion angles. Tibial location significantly affected graft strains for the anatomic, OTT, and isometric socket location. CLINICAL RELEVANCE: This study improves the knowledge on ACL anisometry and strain and helps surgeons to better understand the consequences of socket positioning during intra-articular ACL reconstruction.
通过磁共振成像（MRI）和双荧光透视成像技术，在膝关节上、下台阶和坐下站起运动过程中，评估健康膝关节中各种股骨和胫骨插座位置的前交叉韧带（ACL）理论移植物的体内各向异性和应变。
18 个健康的膝关节通过 MRI 和双荧光透视成像技术进行成像，在膝关节上、下台阶和坐下站起运动过程中，使用 144 个连接到胫骨前内、中央和后外侧附着点的理论插座位置，对外侧股骨髁的内侧进行各向异性映射。测量每个理论移植物的三维包裹路径。比较解剖、过顶（OTT）和最等距（等距）股骨插座位置以及胫骨插入点之间的差异。
在髁间切迹后最接近近-远方向的区域发现各向异性最小。在 Blumensaat 线的中间位置发现最等距的附着部位，在上、下台阶运动过程中分别有 2%和 6%的应变。随着屈曲角度的增加，股骨后附着导致移植物长度减小，而前-远附着导致移植物长度随着屈曲角度的增加而增加。在胫骨插入点之间，解剖、OTT 和等距移植物的各向异性存在差异（P<0.001）。在较深的屈曲角度下，解剖移植物比 OTT 和等距移植物的各向异性更明显（P<0.001）。
髁间切迹后最接近近-远方向的区域发现各向异性最小。在等距和 OTT 位置进行 ACL 重建会导致非解剖移植物行为，这可能会在较深的屈曲角度下过度限制膝关节。胫骨位置显著影响解剖、OTT 和等距插座位置的移植物应变。
本研究提高了对 ACL 各向异性和应变的认识，有助于外科医生更好地理解关节内 ACL 重建过程中插座位置的后果。
