DOS 2017

DOS Kongressen 2017 ·

199

The Influence of Tibial Slope on ACL Graft Failure

Risk is Dependent on Graft Positioning

Steffen Sauer, Robert English, Mark Clatworthy

Orthopaedic Surgery and Sports Medicine, Middle more Hospital / Auckland /

New Zealand

Background:

Increased lateral tibial posterior slope (LTPS) is associated with

higher ACL reconstruction (ACLR) failure rate. Transportal central femoral foot-

print ACLR is associated with higher failure rate compared to transtibial high

anteromedial footprint ACLR due to graft anisometry.

Purpose / Aim of Study:

The purpose of this study was to investigate wheth-

er the influence of tibial slope on ACL graft failure risk is dependent on graft

positioning.

Materials and Methods:

Out of 1480 consecutive hamstring ACL reconstruc-

tions, 30 transportal (central femoral tunnel placement) and 30 transtibial (high

anteromedial tunnel placement) ACLR failures were evaluated and matched

one- to-one with non-failure control participants by age, sex, graft and sur-

gical technique. Lateral tibial slope was assessed on MRI using the technique

described by Hashemi.

Findings / Results:

The risk of graft failure in the transportal group increased

by 40.5 percent per degree of increasing LTPS (odds ratio 1.4; 95% CI, 1,05 -

1,87; p=.02). The transportal failure group showed a significantly higher mean

tibial slope of 8.6 degrees compared to both the transportal control group with

7.1 degrees (p=.03) and the transtibial failure group with 7.2 degrees (p=.04).

Increased tibial slope was associated with shorter time to reconstruction failure

(p=.002). The difference between slopes in the transtibial failure group (7.2

degrees) compared to the transtibial control group (7.1 degrees) was not sig-

nificant (p=0.56).

Conclusions:

Increased LTPS is associated with increased risk of graft fail-

ure only in transportal ACLR, not in transtibial ACLR. Slope related graft strain

may be potentiated by anisometric ACL graft placement. Especially in paediat-

ric ACLR, where increased LTPS is found, non- isometric ACL graft placement

should be avoided.

No conflicts of interest reported

151.