Insall–Salvati index is associated with anterior cruciate ligament tears in men: A Case-controlled study

Abstract

Purpose Many factors in the etiology of anterior cruciate ligament (ACL) tears, predisposing factors related to knee morphology have also been reported. This study aimed to determine whether the Insall–Salvati (IS) index, which measures patella height, is a predisposing risk factor for ACL tears. Methods The IS index, patellar length (PL), and patellar tendon length (PTL) values of patients (study group) that underwent arthroscopic reconstruction for ACL tears obtained by preoperative magnetic resonance imaging (MRI) were compared with the index values in the preoperative MRIs of patients that underwent knee arthroscopy for reasons besides ACL tears. In addition, the anterior tibial translation (ATT) of both groups was also measured and compared on MRI images. The MRI findings of the subjects included in both study groups were arthroscopically confirmed. Results The mean ages of the study group (n = 120) and control group (n = 90) were 29.1 ± 8.2 years and 31.8 ± 9.8 years, respectively. There was a statistically significant difference between the study and control groups in terms of the PL and PTL values ( p = 0.016 and p = 0.001, respectively). The IS index was statistically significantly higher in the study group with ACL tears ( p = 0.009). The ATT was 8.61 ± 4.68 mm in the study group and 3.80 ± 1.92 mm in the control group. The ATT results of both groups were evaluated, and it was found that the study group was significantly higher than the control group ( p = 0.001) Conclusions As a result of our current study, we observed higher IS index values in patients with ACL tears than in patients without ACL tears. It should be kept in mind that patella alta, which is associated with a high IS index as one of the factors of knee morphology associated with ACL tears, may play a role in the etiology of ACL tears.