Abstract
The purpose of this study was initially to examine the effect of tibial slope on anterior tibial translation in the ACL deficient knee measured objectively using the KT 1000 arthrometer. Patients were then evaluated one year post ACL reconstruction to determine the effect of tibial slope on the outcome of ACL reconstruction.
One-hundred patients (male = 70, female 30) aged between 14 and 49 years (Mean = 28.70, SD 8.80) with a diagnosis of isolated anterior cruciate ligament rupture were prospectively recruited. All participants had intact ACLs of the contralateral limb. The following information was recorded for all patients preoperatively and one year post surgery; time from injury to surgery, IKDC objective and subjective assessment and KT 1000 arthrometer readings. Tibial slope was assessed from long tibial lateral x-rays as described by Dejour and Bonnin. Finally, assessment of the menisci occurred intra-operatively. Tibial slope was correlated with KT 1000, meniscal integrity and IKDC assessments. Patients underwent an arthroscopic hamstring ACL reconstruction using Endobutton and Intrafix fixation. All procedures were performed by one surgeon
Pre Reconstruction – Bivariate correlations showed a significant correlation between tibial slope and KT 1000 (r= .29, p < .001). This relation was strengthened when the integrity of the menisci were controlled for (r = .32, p < . 001). When time to surgery was controlled for, correlations between tibial slope and KT 1000 were unaffected. There was also a negative correlation between medial meniscal integrity and time to surgery (r = −.41, p < . 001). No relationships between time to surgery and KT 1000 were evident
Post Reconstruction – Eighty patients were evaluated at a one year post surgery. One patient had a rerupture. The mean KT 1000 difference was 1mm. KT 1000 was > 2mm in 9% and > 5mm in the re rupture only. The mean subjective IKDC score was 89. Using objective IKDC 89% were classified as normal, 10% as nearly normal and 1% as severely abnormal (the rerupture). Bivariate correlations showed no significant correlation between tibial slope and post operative KT 1000 (r= .178, p = .0.115).
This study demonstrates a significant relationship between increasing tibial slope and anterior tibial translation of the ACL deficient knee. The relationship did not exist in the post ACL reconstructed knee. However this needs to be investigated further with greater numbers and in the ACL revision group.
The abstracts were prepared by Editorial Secretary Jean-Claude Theis. Correspondence should be addressed to NZOA at Department of Orthopaedic Surgery, Dunedin Hospital, Private Bag 1921, Dunedin, New Zealand.
