Time-zero quantitative pivot-shift after combined anterior cruciate ligament and anterolateral ligament...

Lateral extra-articular procedures are increasingly used to improve rotational stability during anterior cruciate ligament reconstruction (ACLR), particularly in high-grade pivot-shift knees. However, whether concomitant anterolateral ligament reconstruction (ALLR) provides different intraoperative (time-zero) rotational stability when combined with single-bundle (SB) versus double-bundle (DB) hamstring ACLR remains unclear. We compared stepwise intraoperative laxity in pivot-shift grade 2-3 knees under anesthesia.

Consecutive primary hamstrings ACLR with concomitant ALLR were retrospectively reviewed. Laxity was assessed at baseline (before incision), after ACLR, and after ACLR + ALLR. Rotational laxity was quantified using an inertial sensor as injured-to-contralateral ratios for tibial acceleration and external rotational angular velocity (ERAV). Anterior laxity was side-to-side anterior tibial translation (ATT) using a Rolimeter. Linear mixed-effects models tested stage, technique, and their interaction; a prespecified analysis of covariance adjusted for the post-ACLR value.

Sixty-four patients were included (SB, n = 33; DB, n = 31). Baseline instability was greater in DB (pivot-shift grade 3: 83.9% vs 45.5%, P = 0.002). Rotational laxity improved stepwise in both groups and decreased further after ALLR. At the final stage, DB showed higher acceleration and ERAV ratios (P = 0.016 and P = 0.034); ATT did not differ (P = 0.551). Stage × technique interactions were significant for both rotational metrics (both P < 0.001). In the adjusted analysis, between-group differences were not significant (all P > 0.05).

In pivot-shift grade 2-3 knees undergoing ACLR with ALLR, rotational laxity improved stepwise and decreased further after ALLR regardless of the intra-articular technique. After adjustment for post-ACLR residual laxity, no significant between-technique differences were observed at time zero.