Correlation between anterior cruciate ligament graft obliquity and tibial rotation during dynamic pivoting activities in patients with anatomic anterior cruciate ligament reconstruction: an in vivo examination

Abstract

Purpose: To investigate the effect of coronal- and sagittal-plane anterior cruciate ligament (ACL) graft obliquity on tibial rotation (TR) range of motion (ROM) during dynamic pivoting activities after ACL reconstruction with bone-patellar tendon-bone (BPTB) autograft.

Methods: We evaluated 19 ACL-reconstructed patients (mean age, 29 years; age range, 18 to 38 years; mean time interval postoperatively, 19.9 months) and 19 matched control subjects (mean age, 30.6 years; age range, 24 to 37 years) using motion analysis during (1) descending a stairway and pivoting and (2) landing from a jump and pivoting. Magnetic resonance imaging was used to measure the coronal and sagittal ACL graft angle. The dependent variables were TR ROM during pivoting and the side-to-side difference (SSD) in TR ROM between the reconstructed knee and the contralateral intact knee.

Results: TR ROM of the ACL-reconstructed knee was significantly increased compared with both the contralateral intact knee and the healthy control knee (P < .05). A significant positive correlation was observed between TR ROM and coronal ACL graft angle (r = 0.727, P = .0006 for descending and pivoting; r = 0.795, P = .0001 for landing and pivoting) as well as between SSD of TR ROM and coronal ACL graft angle (r = 0.789, P < .0001 for descending and pivoting; r = 0.799, P < .0001 for landing and pivoting). No correlation was found with the sagittal ACL graft angle.

Conclusions: After ACL reconstruction with a BPTB graft, patients' knees showed higher TR values than their uninjured knees and the knees of uninjured control volunteers during dynamic pivoting activities. The findings of this study show that TR was better restored in ACL-reconstructed patients with a more oblique graft in the coronal plane. A similar relation was not observed for graft orientation in the sagittal plane. Although these data do not imply a cause-and-effect relation between the 2 variables, they may indicate that a more oblique placement of a single BPTB ACL graft in the coronal plane is correlated with better control of TR.

Level of evidence: Level IV, case series.