2017 ISAKOS Biennial Congress ePoster #1046

 

Lateral Tibiofemoral Morphology is Associated with Knee Global Rotation in ACL-Ruptured Patients: A Correlational Study Between Bone Morphology and Knee Rotatory Laxity

Renato Andrade, BSc, Porto PORTUGAL
Rogério B. Pereira, BHKin, BSc, Porto PORTUGAL
Ana Leal, MSc, Guimarães PORTUGAL
Sebastiano Vasta, MD, Rome ITALY
Nuno Sevivas, MD, PhD, Póvoa De Varzim PORTUGAL
André Sarmento, MD, Porto, Seleccione PORTUGAL
Luis Silva, MD, Guarda PORTUGAL
Marco Freitas, BSc, Porto PORTUGAL
Ernesto Pinho, BSc, Porto PORTUGAL
Sara Garrido, BSc, Porto PORTUGAL
Rui Aguiar, MD, Porto PORTUGAL
João Espregueira-Mendes, MD, PhD, Porto PORTUGAL

Clinica do Dragão, Espregueira-Mendes Sports Centre - FIFA Medical Centre of Excellence; Dom Henrique Research Centre., Porto, PORTUGAL

FDA Status Not Applicable

Summary

Knee laxity measurement within MRI provides a safe tool to objectively measure the knee sagittal and rotatory laxity. Bone morphology of the lateral femoral condyle has been suggested as a potential risk factor for ACL injury. Tibiofemoral lateral compartment’s radiographic morphology is associated with knee global rotation laxity in patients with ACL rupture.

Abstract

Introduction

Tibiofemoral bone morphology has been proposed as a potential risk factor for anterior cruciate ligament (ACL) rupture, with recent increasing interest in the lateral femoral condyle. In addition, concomitant multiplanar instrumented laxity measurement (sagittal and rotatory) and magnetic resonance imaging (MRI) may provide a more sensitive diagnosis of the anterior cruciate ligament (ACL) injury. This work aims to assess the association between knee sagittal and rotatory laxity and tibiofemoral lateral compartment’s morphology.

Material And Methods

Patients with suspicion of ACL tear were prospectively referred to perform knee instrumented laxity measurement (Porto Knee Testing Device, Soplast-Moura, Moutinho & Morais, S.A.) concomitantly with MRI. Obtained images were measured to calculate the tibial displacement in relation to the lateral femoral condyle. Measurement variables included lateral tibial plates and lateral femoral condyles relative position at rest, with posteroanterior stress, and with internal and external stress rotation. In addition, tibial displacement from rest to stressed position was measured, as well as, the combined measurement of internal and external rotation.
In addition, radiographic measurements of the distal epiphysis/diaphysis of the femur and proximal epiphysis of the tibia were performed on lateral radiographs. The parameters included the anteroposterior-flattened surface of the femur’s lateral condyle (XY), anteroposterior distance of the tibial plateaus (AB), and a morphological ratio between these two parameters (XY/AB).
In order to assess the linear correlation between two variables, the Pearson’s correlation coefficient was computed. In addition, the sample was divided into two groups according the ratio XY/AB, i.e., it was found the ratio median value (0.466) and separated accordingly: group 1 (<0.466) and group 2 (>0.466). The differences between group 1 and 2 were evaluated using independent sample t test.

Results

A total of 20 patients (30.7 ± 9.7 years old, 15 males and 5 females) with an ACL total tear were included in this study. It was found significant correlation between the calculated value of tibial lateral plateau internal rotation plus external rotation (global rotation) and the calculated ratio XY/AB (r=-0.581, P<0.05). After subgrouping, it was found statistical significant differences between group 1 and 2, concerning the tibial lateral plateau internal rotation plus external rotation (mean values 9.3 vs. 2.3, P=0.017).

Conclusion

There was a significant association between the tibiofemoral lateral compartment morphology and knee laxity measurements. Patients with a smaller XY/AB ratio showed higher values of global knee rotatory laxity (knee internal rotation plus external rotation). In this sense, patients with smaller distances of the anteroposterior-flattened surface of the femur’s lateral condyle - in relation to the anteroposterior distance of the tibial plateaus – seem to have higher rotatory laxity. This may yield an important role in clinical advisement within the scope injury risk stratification and secondary prevention.