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A review on range of tibial rotation432and soft tissue movement are eliminated and pure bony movements are measured. Although there were differences between the patients studied (see table 4) it can be concluded, based on the included studies, that in both single and double bundle ACL reconstruction, the range of tibial rotation after ACL reconstruction is diminished directly after the reconstruction. On the down side, CAS is used intra-operatively, which eliminates muscle tone, as in cadaveric research, and is essentially in an unloaded situation. As a consequence, a reduced intraoperative range of tibial rotation cannot be related to the clinical situation. As measuring with CAS instruments is an invasive procedure, preferably performed during surgery, it is hard to reevaluate subjects over time. Also, a comparison with normal pre-injury state is difficult. Using intraoperative measurements may also be incomparable to the clinical situation: First, after reconstruction, lengthening of the graft occurs after 2000 cycles of knee flexion-extension under moderate loading.8 Due to creep of the ACL graft, lengthening of up to 20mm has been reported8 , which may lead to residual, or perhaps renewed, laxity. Second, when hamstring tendons have been harvested to be used as a graft, one of the active stabilising structures counteracting external rotation of the tibia is weakened. CAS however is a very accurate and reproducible tool to measure tibial rotation. A single examiner reproducibility of rotatory laxity is shown to be as little as 1,6 degrees.21 Although motion capture systems show promising results in respect to accuracy31 and skin motion artefact reduction tools have become more precise3, the current literature regarding the use of motion capture systems in ACL reconstruction is too diverse to advise on a standard protocol. MRI, CT and biplanar fluoroscopy are only of limited use in studying a dynamic situation such as tibial rotation. Another issue is the difference in patient characteristics and the intactness of other stabilising structures around the knee joint. In clinical studies, Haughom15 and Christino10 report a higher range of tibial rotation in females, which is not supported by Hemmerich.16 Also, adolescents have shown to have higher range of tibial rotation compared to adults.10The menisci, the capsule, the anterolateral ligament and the iliotibial band restrain the amount of internal rotation.19 Concomitant injury to these structures may lead to an increased range of tibial rotation. None of the Mark Zee.indd 43 03-01-2024 08:56