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Objectives and questions: Graft failure and persistent rotational instability remain concerns after ACL reconstruction (ACLR). Lateral extra-articular tenodesis (LET) is increasingly used in high-risk patients. The modified Lemaire technique is widely applied. However, combined ACLR and LET may result in femoral tunnel conflict. Previous studies report conflict rates up to 67–70% when LET femoral drill tunnels are used. Onlay fixation with a knotless all-suture anchor avoids additional femoral drilling, but its effect on tunnel conflict has not been systematically evaluated. This study evaluated the risk of femoral tunnel conflict after combined ACLR and modified Lemaire LET using knotless all-suture anchor onlay fixation. We hypothesized a low risk of tunnel conflict with preservation of ACL femoral tunnel integrity.

Material and methods: Patients undergoing primary ACLR between June and December 2025 using a semitendinosus autograft combined with modified Lemaire LET and available postoperative cone-beam CT (CBCT) were included. The ACL femoral tunnel was drilled via the anteromedial portal at 120° knee flexion. A 2.4-mm guidewire was placed anatomically and overreamed to 25 mm according to graft diameter. For LET, an 8 × 1 cm iliotibial band strip was harvested, preserving the distal insertion at Gerdy’s tubercle and the posterior 1 cm. The graft was passed deep to the lateral collateral ligament. Femoral fixation was performed using a 2.6-mm knotless all-suture anchor (FiberTak, Arthrex) placed slightly proximal and posterior to the lateral femoral epicondyle. The insertion device was oriented 30° distally and 30° anteriorly and advanced 21 mm. Fixation was completed at 60°–70° flexion in neutral rotation. Postoperative CBCT (0.2-mm slices; MedSeries H22 DVT Mark 3, SCS, Germany) was used to measure minimal distances between ACL and LET tunnels in sagittal, coronal, and axial planes. Tunnel conflict was defined as <2 mm minimal distance.

Results: Eighteen patients (13 male, 5 female; mean age 20.2 ± 7.7 years, range 10–36) were analyzed. All underwent primary ACLR with quadrupled semitendinosus autograft; no intraoperative changes to LET fixation were required. CBCT showed anatomic ACL femoral tunnel placement in all cases and LET anchor positioning slightly proximal and posterior to the lateral femoral epicondyle without ACL tunnel penetration. Mean minimal ACL–LET distance was 5.1 ± 2.7 mm (range 2–12 mm), smallest in the sagittal plane. No tunnel conflict (<2 mm), convergence, or violation occurred (0/18).

Discussion and conclusions: Combined ACLR and modified Lemaire LET using knotless all-suture anchor onlay fixation was not associated with femoral tunnel conflict in this series, contrasting with high conflict rates reported for drill-tunnel LET techniques. Angling the anchor even more anteriorly and distally than 30° may further increase safety margins. Onlay fixation represents a safe and reproducible option to minimize femoral tunnel conflict in combined ACLR and LET. Larger studies with clinical follow-up are warranted.