2015 ISAKOS Biennial Congress ePoster #1274
Correlation Between Pivot Shift and Static Laxity Test During Navigated ACL Reconstruction
Sivakumar Nelliyan, MS, Pudukkottai, TAMIL NADU INDIA
Cecilia Signorelli, PhD, Bologna, BO ITALY
Nicola Francesco Lopomo, PhD, MSc Eng, Bologna ITALY
Tommaso Bonanzinga, MD, Bologna ITALY
Giulio Maria Marcheggiani-Muccioli, MD, PhD, Bologna ITALY
Federico Raggi, MD, Bologna ITALY
Stefano Zaffagnini, MD, Prof., Bologna ITALY
Maurilio Marcacci, MD, Milano, Milano ITALY
Istituto Ortopedico Rizzoli, Laboratorio di Biomeccanica e Innovazione Tecnologica / Clinica Ortopedica e Traumatologica II, Bologna (Italy), BOLOGNA, ITALY
FDA Status Not Applicable
Summary: The fact of finding NO correlation between pivot shift test and static laxity tests highlighted the importance of assessing both dynamic and static laxity tests during the assessment of ACL insufficiency.
Usually, in the clinical evaluation of Anterior Cruciate Ligament (ACL) insufficiency, Lachman and drawer tests are used to assess static laxity whereas PS test is used to assess the dynamic laxity. The goal of this work was to analyze the correlation between PS test and static laxity tests, intra-operatively acquired by using a navigation system.
Nintytwo patients with ACL injury who consecutively underwent ACL reconstructions between 2009 and 2014 were included. Before performing the reconstruction, static laxity was tested by performing several tests, including Lachman (AP30) and internal/external rotation at 30° (IE30) of flexion, whereas dynamic laxity by doing PS test. Specifically, overall anterior-posterior displacement of the joint center and internal/external rotations were analyzed for each static laxity test. Further, for the PS the overall displacement of the lateral compartment in the anterior-posterior direction (AP-PS) and the corresponding internal-external rotation range during subluxation (IE-PS) . The Pearson Product-Moment Correlation Coefficient r was calculated to determine the correlation between the ranges in anterior-posterior direction and internal-external rotation reached during the PS test and the corresponding ranges achieved during laxity tests.
Mean value of translation for AP30 was 11.6 ± 3.5 mm. Mean value of rotation for IE30 was 26.6° ± 4.8°. Mean value of translation for AP-PS was 22.2 ± 9.2 mm, whereas for IE-PS was 17.9° ± 5.5°. Correlation analysis showed no correlation between any of the PS parameters and the outcome of static laxity tests. Specifically, a r = 0.19 (p = 0.1898) and a r = 0.21 (p = 0.075) were found between AP30 and AP-PS and IE30 and IE-PS, respectively.
Our analysis was helpful for characterizing patient-specific laxity before the reconstruction, thus highlighting the clinical relevance of the PS test compared to static laxity test. Furthermore, since there was no correlation between PS test and static laxity test, surgeon should use both the tests to assess the joint laxity and perform a correct clinical evaluation.
 Lopomo N, Zaffagnini S, Bignozzi S, Visani A, Marcacci M. Pivot-shift test: analysis and quantification of knee laxity parameters using a navigation system.J Orthop Res. 2010 Feb;28(2):164-9. doi: 10.1002/jor.20966.