Page 68 - Demo

Chapter 366rotation is more reliable and allows for repeatable measurements over time. In our study we used the contralateral intact knee as a comparison. There is sparse literature available that shows that the contralateral intact knee also shows an altered movement pattern after an ACL injury. This has been particularly demonstrated in the postoperative phase during hop testing.15Whether this occurs immediately after the injury is unclear. It also has been shown that abnormal geometrical characteristics in the knee, that may be present bilaterally, pose a risk factor for ACL injury.27 Whether and how this affects the kinematics of the knee is unclear. We can compare our results to available literature regarding healthy knees. Liu et al studied knee kinematics during walking and running in healthy subjects.28 Although the study of Liu et al use a different method to measure range of tibial rotation it can serve as a basis to compare our results to. Liu showed a rTR of 14.0 ± 4 degrees during walking at 3km/h and 15.5 ± 4.1 degrees during walking at 5km/h. These results seem comparable to our results during level walking, although we have not recorded the walking pace of our subjects. Also, leg dominance may be a potential confounder. In our population 8 out of 10 ACL injured knees were dominant legs. Whether and how this influenced our results is unclear. Small sample size is an issue that has to be taken into account when evaluating our results. The narrow inclusion and exclusion criteria are mainly responsible for the small sample size. Subjects with concomitant injury were excluded as injury to the menisci and anterolateral structures of the knee are known to influence degree of tibial rotation.23 This narrows the number of eligible subjects. As some subjects with a recent ACL injury may have been reluctant to participate in the study after being informed on the hop test, a certain amount of selection bias may be present. Although the inclusion criteria were strictly based on the Dutch guideline for ACL injury, the motivation for definite participation could have been subject to individual variables like available time or fear for reinjury. Subjects with a greater feeling of giving way may not have participated.Mark Zee.indd 66 03-01-2024 08:56