Summary

Several anatomical parameters have been identified to differ significantly between patients with failed ACL reconstruction and those without a documented failure. A posterior lateral tibial slope higher than 8.5° has been reported to have sensitivity of 0.77 and specificity of 0.94 in detecting ACL failure.

Abstract

Purpose

To identify anatomical parameters of knee joint correlating with
anterior cruciate ligament (ACL) reconstruction failure between patients
that presented a failed ACL reconstruction, and a control group with
successful ACL reconstruction.

Methods

Forty-three (34 males, 9 females) who experienced graft failure
after ACL reconstruction were enrolled in the Failed Group. These
patients were matched to a Control group of 43 patients that underwent
primary ACL reconstruction with a minimum follow-up of 24 months. On
Magnetic Resonance Imaging, the following parameters were evaluated:
transepicondylar distance (TE), lateral and medial femoral condyles
(LFCw, MFCw) and tibial plateau width (LTPw, MTPw), Notch Width Index
(NWI) and the ratio of width and height of the fermoral notch (N-ratio),
ratio between the height and depth of the lateral and medial femoral
condyle (LFC-ratio, MFC-ratio), lateral and medial posterior tibial
slopes (LTPs and MTPs) and anterior subluxation of the lateral and medial
tibial plateau respect to femoral condyles (LTPsublx and MTPsublx). The
multivariate regression, with backward elimination, including only the
previously identified significant variables, defined the independent
predictors for revision surgery.

Results

The anatomical variables that resulted significantly different
between the two study groups were both the posterior tibial slopes (LTPs,
MTPs), both subluxations (LTPsublx, MTPsulx), and the MCFw. LTPs was the
most significant independent predictor (p < 0.001) for graft failure with
an optimal cut-off of 8.5°.

Conclusions

Several anatomical parameters have been identified to differ
significantly between patients with failed ACL reconstruction and those
without a documented failure. A posterior lateral tibial slope higher
than 8.5° has been reported to have sensitivity of 0.77 and specificity
of 0.94 in detecting ACL failure.