MRI Volume and Signal Intensity of ACL Graft Predict Clinical, Functional, and Patient-Oriented Outcome Measures After ACL Reconstruction

Abstract

Background Clinical, functional and patient-oriented outcomes are commonly used to evaluate the efficacy of treatments following ACL injury; however, these evaluation techniques do not directly measure the biomechanical changes that occur with healing. Purpose To determine if the magnetic resonance (MR) image-derived parameters of graft volume and signal intensity (SI), which have been used to predict the biomechanical (i.e., structural properties) of the graft in animal models, correlate with commonly used clinical (anteroposterior (AP) knee laxity), functional (1-leg hop) and patient-oriented outcome measures (KOOS) in patients 3- and 5-years after ACL reconstruction. Study Design Descriptive Laboratory Study Methods Using a subset of participants enrolled in an ongoing ACL reconstruction clinical trial, AP knee laxity, 1-legged hop test, and KOOS were assessed at 3- and 5-year follow-up. 3-D T1-weighted MR images were collected at each visit. Both the volume and median SI of the healing graft were determined and used as predictors in a multiple regression linear model to predict the traditional outcome measures. Results Graft volume combined with median SI in a multiple linear regression model predicted 1-legged hop test at both the 3-year and 5-year follow-up visits (R2=.40, p=.008 and R2=.62, p=.003, respectively). Similar results were found with 5-year follow up for the KOOS quality of life (R2=.49, p=.012), sport_function (R2=.37, p=.048), pain (R2=.46, p=.017) and symptoms (R2=.45, p=.021) sub-scores, though these variables were not significant at 3 years. The multiple linear regression model for AP knee laxity at 5-year follow-up approached significance (R2=.36, p=.088). Conclusion The MR parameters (volume and median SI) used to predict ex vivo biomechanical properties of the graft in an animal model have the ability to predict clinical or in vivo outcome measures in patients at 3- and 5-year follow-up.

Return to sport after ACL reconstruction: how, when and why? A narrative review of current evidence

“…This should not be neglected, as lack of incorporation of the graft and biological failure are wellrecognised causes of poor outcomes after ACL reconstruction (3). Moreover, graft healing, measured by graft signal intensity on magnetic resonance imaging (MRI), has been shown to affect anteroposterior (AP) laxity and clinical or functional outcomes (4). Therefore, the clinician should be aware that graft maturation is a slow process that can even take longer than two years (5,6), and must be sure that it is complete before allowing activities that could stress an incompletely remodelled graft.…”

The Effect of Anterior Cruciate Ligament Reconstruction Technique on Graft Signal Intensity at Mid-Term Follow-Up

“…In Press(In Press):e14060. 5 U n c o r r e c t e d P r o o f the entire course of the graft has been studied and it was shown that IGSI is a dynamic process of healing and by 2-years postreconstruction, the graft should resume uniformly low GSI on MRI (18,19 (2,20). In our study, IGSI of the IAP was observed in 36.6 %, and only 9.8% of patients showed low GSI of the entire graft course.…”

“…GSI in the early postreconstruction period has been well studied, however few studies evaluated the GSI at midor long-term follow-up (2,4,17). In short-term studies, Iran J Radiol.…”

“…In the period from January 2008 until October 2009, 107 patients underwent TT with RIGIDfix fixation and in the period from November 2008 until July 2010, 132 patients underwent AM with Endobutton fixation. Based on the review of clinical notes, 35 patients from each group met the following study inclusion criteria: (1) autologous quadruple stranded semitendinosusgracillis graft (STGR), (2) no history of prior knee surgery, (3) no history of total meniscectomy or concomitant collateral ligament disruption, (4) 16 -45 years at operation, (5) sports activity of at least four on Tegner scale prior to the ACL rupture, (6) no readmissions or records of knee related problems after ACL-R and (7) no MR contraindication. Fifty patients were successfully contacted; their demographic characteristics are shown in Table 1.…”

“…Early studies described intact anterior cruciate ligament (ACL) graft as having low graft signal intensity (GSI) (1). However, several studies in the past two decades have shown that intact grafts may show variable degrees of IGSI (2)(3)(4). In the literature, various underlying causes are associated with IGSI; graft impingement (5), imaging artifacts (6), incomplete maturation of the graft (3), enlargement of the drilling tunnels (7), and degenerative changes (4).…”