Evaluation of Anterior Tibial Translation Under Physiological Axial Load After ACL Reconstruction With Lateral Extra-articular Tenodesis

Abstract

Background: Postoperative laxity correlates with negative clinical outcomes after anterior cruciate ligament reconstruction (ACLR). The influence of lateral extra-articular tenodesis (LET) on anteroposterior translation is unclear.

Purpose/hypothesis: This study aimed to evaluate the reduction in radiographic static anterior tibial translation (SATT) and dynamic anterior tibial translation (DATT) after LET as an adjunctive procedure to ACLR. It was hypothesized that adding a LET procedure would have no effect on postoperative SATT and DATT.

Study design: Cohort study; Level of evidence, 3.

Methods: Patients who underwent primary ACLR with hamstring tendon autografts between 2020 and 2022 were reviewed, and those who underwent ACLR and LET as an anterolateral associate procedure were paired 1 to 1 with those who underwent isolated ACLR (control) based on age, sex, preoperative SATT, and posterior tibial slope (PTS). The indications for LET were age <18 years and anterolateral rotary instability (grade ≥2 pivot shift). A previously validated technique was used to measure SATT, DATT, and PTS on lateral weightbearing and lateral stress knee radiographs. Preoperative and 9-month postoperative radiographs were compared between the 2 groups.

Results: A total of 72 patients were included in the analysis (n = 36 patients in each group). The inter- and intraobserver reliability of the SATT, DATT, and PTS measurements was excellent (intraclass correlation coefficients, 0.88-0.99). The mean pre- and postoperative SATT in the ACLR+LET group was 2.44 ± 2.90 mm and 2.44 ± 2.38 mm, respectively, compared with 2.60 ± 2.99 mm and 2.12 ± 2.74 mm, respectively, in the control group. The mean pre- and postoperative reduction in side-to-side DATT in the ACLR+LET group was 5.44 ± 4.65 mm and 1.13 ± 2.95 mm, respectively, compared with 5.03 ± 3.66 mm and 2 ± 3.12 mm, respectively, in the control group. There was no pre- to postoperative difference in SATT (P = .51). However, the side-to-side DATT was reduced by 3.66 ± 3.37 mm postoperatively (P < .001), without significant differences between groups (P = .24).

Conclusion: Including a LET procedure for patients undergoing ACLR did not reduce SATT; that is, it did not decrease the amount of tibial translation due to physiological axial load.

Keywords: Lemaire procedure; anterior cruciate ligament reconstruction; arthroscopy; dynamic anterior tibial translation; lateral extra-articular tenodesis; static anterior tibial translation.

Figure 1.

A lateral right knee radiograph demonstrating measurement of the PTS on a monopodal weightbearing radiograph. The PTS is the angle a, formed between line B, perpendicular to the tibial diaphyseal axis (line A), and line C, tangent to the most superior points at the anterior and posterior edges of the medial plateau. PTS, posterior tibial slope. Line A is defined by the line passing through the center of the two circles. The circles are placed 5 and 15cm from the joint surface.

Figure 2.

(A) A lateral left knee radiograph demonstrating SATT measurement on a monopodal weightbearing radiograph. The posterior tibial cortex is the reference (line A). Two lines are traced parallel to line A and tangent to the posterior part of the medial plateau (line B) and the medial femoral condyle (line C). The SATT is the distance between lines B and C. (B) A lateral knee radiograph demonstrating measurement of DATT on Telos stress radiograph using 150 N of force applied on the femur (arrow 1) and the tibia (arrow 2) in opposite directions. The posterior tibial cortex is the reference (line a). Two lines are traced parallel to line a and tangent to the posterior part of the medial plateau (line b) and the medial femoral condyle (line c). The DATT is the distance between lines b and c. DATT, dynamic anterior tibial translation; SATT, static anterior tibial translation.