Predictors of Tunnel Widening After Anterior Cruciate Ligament Reconstruction.

BACKGROUND

Posterior tibial slope (PTS) has been implicated in tunnel widening after anterior cruciate ligament reconstruction (ACLR), yet its precise effect remains unclear. Additionally, the influence of lateral extra-articular tenodesis (LET) and meniscus root injuries on tunnel widening has not been well established.

PURPOSE: To evaluate the effect of medial and lateral PTS, LET, and meniscus root injuries on tibial and femoral tunnel widening after ACL reconstruction using a hamstring tendon graft.

STUDY

DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 307 patients who underwent primary ACLR with a hamstring tendon graft were included. Tibial and femoral tunnel diameters were measured immediately postoperatively and at 2-year follow-up. PTS was assessed by long lateral radiographs. Univariate and multivariate regression models were used to identify predictors of tunnel widening.

RESULTS

At 2 years, the mean ± Standard Deviation (SD) tibial tunnel diameter increased from 9.46 ± 1.00 mm postoperatively to 11.35 ± 1.55 mm (P < .001), and the mean femoral tunnel diameter increased from 9.27 ± 0.83 mm to 11.52 ± 1.63 mm (P < .001). Univariate analysis demonstrated that steeper medial and lateral PTS were significantly associated with tibial (P < .0001) and femoral (P < .0001) tunnel widening. Meniscus root injuries (P = .0024) and higher body mass index (P = .0127) were also associated with increased tunnel widening. In multivariate regression, medial PTS (β = -0.321; P < .0001), lateral PTS (β = -0.137; P = .0356), LET (β = 0.2207; P = .0257), and meniscus root injuries (P = .0024) remained independent predictors of tunnel widening.

CONCLUSION

Steeper medial and lateral PTSs, the addition of LET, and the presence of meniscus root injuries are significant independent predictors of tibial and femoral tunnel widening after ACLR with a hamstring graft. These findings highlight key anatomic and surgical factors influencing postoperative tunnel remodeling and emphasize the importance of considering these variables in ACLR planning.