Description
Introduction
Each anteromedial bundle (AMB) and posterolateral bundle (PLB) of the anterior cruciate ligament (ACL) exhibits different effects during the range of motion (ROM) of the knee.[1]
We quantitatively measure the graft length changes during ROM and adjust the knee flexion angle when fixating the grafts.
PURPOSE
To investigate the factors that increase the graft length changes that cause excessive tension in the ACL reconstruction using hamstring tendon.
METHODS
93 knees (37 male and 55 female, 31 y.o.)
Primary anatomical double-bundle ACL reconstruction with hamstring tendon
General factors
Gender, age, waiting period from injury to surgery
Anatomicalal factors
Hyper extension, tibial posterior slope
Surgical factors
Bone tunnel communication confirmed by three-dimensional computed tomography
Knee laxity
Anterior translation in Lachman test, rotational instability in pivot shift test, and positive pivot shift on the non-injured knee [Fig. 1], and meniscus injury
Graft length changes of the ABM/PLB
Quantitatively measured using isometric positioner just before the graft fixation during 0o-120o knee flexion [Fig. 2].
Statistical analysis： non-paired t-test and single regression
p < 0.05 as statistically significant
RESULTS
Length change AMB：3.7±2.2 [mm], PLB：6.3±2.7 [mm]
Lachman test 22.2±6.0 [mm] (injured side), 8.0±6.8 [mm] (side-to-side difference)
39 cases have positive pivot shift in non-injured knee
DISCUSSION
Graft length changes were similar to the previous reports.[2,3]
The longer the waiting period, the greater the anterior translation of the tibia. [4]
Hyperextended knee is a negative factor for the ACL reconstruction. [5,6]
Hyperextended knees do not worsen the ACL reconstruction results. [7,8]
The femur rotates externally (tibia rotates internally) during hyperextension.[9]
Tibial internal rotation durin hyperextension might be a factor in reducing AMB length change.
CONCLUSION
Knee flexion angle should be considered when fixating both AMB and PLB grafts, especially in cases with a long waiting period before surgery or cases with a hyperextended knee.
DISCLOSURE
We have no conflict to disclose for this study.
REFERENCES
1. Petersen W. et al. Clin Orthop Relat Res. 2007. 2. Matsumoto A., et al. 14th JOSKAS-JOSSM. 2022. 3. Iwahashi T. et al. Knee Surg Sports Traumatol Arthrosc. 2008. 4. Mishima S., et al. Arthroscopy. 2005. 5. Ueki H., et al. Knee Surg Sports Traumatol Arthrosc. 2018. 6. Guimarães T et al., Orthop J Sports Med. 2021. 7. Saito K et al., Arthroscopy. 2015. 8. Nagai K et al., Knee Surg Sports Traumatol Arthrosc. 2017. 9. Freeman M et al., J Biomech. 2005
