Assessment of rotatory laxity in anterior cruciate ligament-deficient knees using magnetic resonance imaging with Porto-knee testing device

摘要

Purpose Objective evaluation of both antero-posteriortranslation and rotatory laxity of the knee remains a targetto be accomplished. This is true for both preoperativeplanning and postoperative assessment of different ACLreconstruction emerging techniques. The ideal measurement tool should be simple, accurate and reproducible,while enabling to assess both ‘‘anatomy’’ and ‘‘function’’during the same examination. The purpose of this study isto evaluate the clinical effectiveness of a new in-housedeveloped testing device, the so-called Porto-knee testingdevice (PKTD). The PKTD is aimed to be used on theevaluation of both antero-posterior and rotatory laxity ofthe knee during MRI exams.Methods Between 2008 and 2010, 33 patients with ACLdeficient knees were enrolled for the purpose of this study.All patients were evaluated in the office and underanesthesia with Lachman test, lateral pivot-shift test andanterior drawer test. All cases were studied preoperativelywith KT-1000 and MRI with PKTD, and examinationsperformed by independent observers blinded for clinicalevaluation. During MRI, we have used a PKTD that appliesantero-posterior translation and permits free tibial rotationthrough a standardized pressure (46.7 kPa) in the proximalposterior region of the leg. Measurements were taken forboth knees and comparing side-to-side. Five patients withpartial ruptures were excluded from the group of 33.Results For the 28 remaining patients, 3 women and 25men, with mean age of 33.4 ± 9.4 years, 13 left and 15 rightknees were tested. No significant correlation was noticed forLachman test and PKTD results (n.s.). Pivot-shift had astrong positive correlation with the difference in anteriortranslation registered in lateral and medial tibia plateaus ofinjured knees (cor. coefficient = 0.80; p0.05), and withthe difference in this parameter as compared to side-to-side(cor. coefficient = 0.83; p0.05).Considering the KT-1000 difference between injured andhealthy knees, a very strong positive correlation was foundfor side-to-side difference in medial (cor. coeffi-cient = 0.73; p0.05) and lateral (cor. coefficient = 0.5;p0.05) tibial plateau displacement using PKTD.Conclusion The PKTD proved to be a reliable tool inassessment of antero-posterior translation (comparing withKT-1000) and rotatory laxity (compared with lateral pivotshift under anesthesia) of the ACL-deficient knee duringMRI examination