KS3: TIBIAL ROTATION IS RESTORED AFTER ACL RECONSTRUCTION WITH A SINGLE BUNDLE HAMSTRING GRAFT

Abstract

It has been suggested that excessive tibial rotation during pivoting tasks is not controlled by single bundle ACL reconstruction (ACLR). This may be partly explained by graft orientation in the coronal plane. The purpose of this study was to assess tibial rotation after ACLR with an obliquely placed hamstring graft.

18 patients were evaluated. All patients had undergone a primary ACLR for an isolated ACL injury within 6 months of injury. All had a 4 strand graft, either semi-tendinosus alone (ST) or semitendinosus and gracilis (STGR) – 9 in each group, each with 2 females and 7 males. Follow-up was at least 2 years postoperatively and all patients had made a good functional recovery and returned to their pre-injury sporting activities. Evaluation consisted of IKDC 2000, instrumented laxity testing, and 3D motion analysis to record tibial rotation when subjects descended stairs and pivoted 90 degrees on landing using a similar protocol to one which has previously been reported.

All patients had made an excellent recovery (mean IKDC score 100 for both groups) and there were no significant differences between the ST and STGR subjects for any of the background variables including anterior knee laxity. There were no differences in the maximal tibial rotational angle between the operated (mean: 20°, range: 10°– 27°) and non operated limb (mean: 21°, range: 6°– 42°). There was no significant difference between the graft types (ST: 20°, STGR: 21°). Females had greater tibial rotation on both the operated and non-operated sides compared to males.

Contrary to previous reports, we found restoration of normal tibial rotation during the pivoting task after a single bundle ACLR. The lack of difference between the ST and STGR groups suggests that this restoration of normal tibial rotation is due to static rather than dynamic restraints. We suggest that it probably reflects the more horizontal graft orientation in the coronal plane for patients in the current study compared to that reported in previous studies.