Comparison of the use of a laximeter and a triaxial accelerometer for Anterolateral ligament injury diagnosis in ACL deficient knee

Abstract

Objectives: The objective of this study was to compare the use of a laximeter and a triaxial accelerometer, for Anterolateral ligament injury diagnosis of in ACL deficient knee. We hypothesized that a triaxial accelerometer was more effective than a laximeter. Methods: A total of 11 cadaver knees were studied according to a new conservative dissection protocol without damage to the lateral structures. A GnRB® laximeter (Genourob, France) was used to determine anterior tibial translation (AP) of the tibia. Simultaneously, a KiRA® triaxial accelerometer (Kinetic Rapid Assessment) (OrthoKey, Italy) was used to determine two parameters: the AP translation and the Pivot Shift (PS). For each knee, 5 conditions were successively applied: intact knee (intact), knee with ALL (ALLsec) isolated section, knee with ALL and ACL section (ALL + ACLsec). Results: For the laximeter, the ACL and ALL sections led to a significant AP translation increase: + 2.1 mm for the ACL section, and + 0.9 mm for the ALL section. This difference was significant regardless of the level of force applied (p <0.05). For the triaxial accelerometer, the ACL and the ALL sections led to a significant AP translation increase: + 2.8 mm for ACL, and + 1.5 mm for ALL section. In contrast, for the PS, the increase was more consistent. There was a multiplier factor between the ACLsec condition and the ACL + ALLsec condition comparable to that between the intact condition and the ACLsec condition (P> 0.05). Conclusion: Whatever the device, the AP translation difference induced by the ALL injury, of the order of mm, remains too small to make the diagnosis of an ALL injury. The evaluation of the AP translation is therefore not a relevant to diagnostic an ALL injury. With greater increase, the evaluation of the rotatory laxity, through the PS test, is more relevant. In current practice, there is no clinical interest to use a laximeter or accelerometer on AP translation assessment to diagnosis an ALL injury in a deficient ACL knee. On the other hand, the use of a triaxial accelerometer to quantify the lateral tibial plateau acceleration in the pivot shift test appears to be relevant for detecting an ALL injury on a deficient ACL knee. These findings help provide clinical guidelines for more effective objective measures to diagnose ALL injury, and determine the most effective management for each patient.