2025 ISAKOS Biennial Congress ePoster
A Radiographic Investigation Exploring Differences In Static Anterior Tibial Translation Expressed As A Percentage Between Acl Injured Cohort And Controls, In The Hope To Improve Inter-Institutional Utilization Of Normative Values.
Michael J. Dan, Mbbs, PhD, MSc(res), FRACS(oath), Merewether AUSTRALIA
Nicolas Cance, MD, Lyon, Rhône-Alpes FRANCE
Tomas Pineda, MD, Santiago CHILE
Guillaume Demey, MD, Lyon, Rhône Alpes FRANCE
David H. Dejour, MD, Lyon FRANCE
Lyon Ortho Clinic, Lyon, FRANCE
FDA Status Not Applicable
Summary
ACL reconstruction alone, does not improve Static anterior tibial translation (SATT), a slope changing osteotomy is needed to improve this value, however values for SATT are absolute and differ substantially between studies, and also are not scaled for the size of the patient, normalized ratio values will improve comparative data between institutions and studies.
ePosters will be available shortly before Congress
Abstract
Introduction
Static anterior tibial translation(SATT) represents the amount of anterior translation due to axial load. It has been shown to be increased with Anterior Cruciate Ligament(ACL) rupture, meniscal tear and tibial slope. It has also been shown to be correlated with ACL reconstruction failure. ACL reconstruction alone, does not improve SATT. A sagittal plan, slope correcting osteotomy improves SATT, and SATT has recently been used to define the target slope correction post osteotomy. However, absolute values for SATT differ between different institutions differ by over 5mm. Absolute measures differ based on the amount of magnification of the image, which varies based on the radiographic source to image distance, the source to object distance, rotation and whether the medial or lateral condyle is presented to the source first. Scaled, or percentage radiographic measures should correct for these differences.
Purpose
Our goal was to define SATT expressed as a percentage of the medial plateau distance to improve accuracy and inter- institutional utilization of SATT.
Methods
A consecutive series of patients without ligamentous or meniscal injuries between 2019 and 2022 was reviewed. A matched consecutive cohort of patients with nonacute ACL injuries (surgery between 6 and 12 weeks after injury) without concomitant pathology was reviewed. Preoperative SATT and PTS were measured with a previously validated technique on lateral weightbearing knee radiographs. The SATT was expressed as a percentage of the medial plateau distance value and regression analysis was performed to investigate the relationship between SATT % and PTS.
Results
There was 101 controls and 115 patients with an ACL injury were included in this study. The mean SATT % was 3.18 %(SD 5.92 ) and the mean PTS was 10.61º (SD 3.28) in the control cohort. This was significantly different to our ACL mean SATT % of 5.16% (SD 7.41) (p= 0.04) and ACL mean PTS 9.46º (2.85) (p= 0.02). Linear regression analysis showed that for every 1 degree of increase in PTS, there was a 0.08% increase in SATT% in the control cohort, so every 10 degree rise in slope was associated with a 8% increase in SATT%. In the ACL cohort the effect of PTS on SATT% was larger, for every 1 degree of increase in PTS, there was an increase of 0.97% SATT%.
Conclusion
The present study reports a reference SATT percentage value of 3.18% (SD 5.92) in a non-ACL injured cohort, which was lower than in the ACL cohort mean 5.16% (SD 7.41), despite the ACL cohort having a longer medial tibial plateau than the control population. The effect of slope on weight bearing anterior tibial translation was greater in the ACL population compared to the control cohort. These scaled, percentage values should improve the inter institutional usage of SATT.