The incidence of anterior cruciate ligament (ACL) tears in children is rising steadily due to a variety of factors including growing participation in sports. A narrow intercondylar notch is an intrinsic risk factor that is well documented in adults but rarely investigated in children. The objective of this study was to evaluate the potential association between a narrow intercondylar notch and ACL tears in children.

A narrow intercondylar notch is associated with ACL tears.

In a paediatric case-control study, we compared intercondylar notch morphology as assessed by magnetic resonance imaging (MRI) in 49 patients with ACL tears (33 males and 16 females with a mean age of 13.6 years) and 50 controls with normal knees (18 boys and 32 girls with a mean age of 13.8 years). In each participant, posterior tibial slope was measured, as well as the notch width index (NWI) (width of the intercondylar notch over bicondylar width at the same level). In addition, to evaluate anterior impingement, the angle formed by Blumensaat's line and the axis of the tibia (α angle) was measured with the knee extended.

The NWI was significantly lower in the cases than in the controls (0.244±0.02 and 0.263±0.02, respectively; P<0.05). The α angle was also significantly smaller in the cases (138.74°±4.6° vs. 141.30°±7.9° in the controls; P<0.05).

ACL tears are associated with a small NWI in children. A narrow intercondylar notch is an established risk factor for ACL tears and should be sought routinely to determine whether notch-plasty should be performed during the ACL reconstruction procedure in order to decrease the risk of recurrent ACL tears.

III, case-control study.