Early MRI-based quantitative outcomes are associated with a positive functional performance trajectory from 6 to 24 months post-ACL surgery

Abstract

PurposeQuantitative magnetic resonance imaging (qMRI) has been used to determine the failure properties of ACL grafts and native ACL repairs and/or restorations. How these properties relate to future clinical, functional, and patient‐reported outcomes remain unknown. The study objective was to investigate the relationship between non‐contemporaneous qMRI measures and traditional outcome measures following Bridge‐Enhanced ACL Restoration (BEAR). It was hypothesized that qMRI parameters at 6 months would be associated with clinical, functional, and/or patient‐reported outcomes at 6 months, 24 months, and changes from 6 to 24 months post‐surgery. MethodsData of BEAR patients (n = 65) from a randomized control trial of BEAR versus ACL reconstruction (BEAR II Trial; NCT02664545) were utilized retrospectively for the present analysis. Images were acquired using the Constructive Interference in Steady State (CISS) sequence at 6 months post‐surgery. Single‐leg hop test ratios, arthrometric knee laxity values, and International Knee Documentation Committee (IKDC) subjective scores were determined at 6 and 24 months post‐surgery. The associations between traditional outcomes and MRI measures of normalized signal intensity, mean cross‐sectional area (CSA), volume, and estimated failure load of the healing ACL were evaluated based on bivariate correlations and multivariable regression analyses, which considered the potential effects of age, sex, and body mass index. ResultsCSA (r = 0.44, p = 0.01), volume (r = 0.44, p = 0.01), and estimated failure load (r = 0.48, p = 0.01) at 6 months were predictive of the change in single‐leg hop ratio from 6 to 24 months in bivariate analysis. CSA (βstandardized = 0.42, p = 0.01), volume (βstandardized = 0.42, p = 0.01), and estimated failure load (βstandardized = 0.48, p = 0.01) remained significant predictors when considering the demographic variables. No significant associations were observed between MRI variables and either knee laxity or IKDC when adjusting for demographic variables. Signal intensity was also not significant at any timepoint. ConclusionThe qMRI‐based measures of CSA, volume, and estimated failure load were predictive of a positive functional outcome trajectory from 6 to 24 months post‐surgery. These variables measured using qMRI at 6 months post‐surgery could serve as prospective markers of the functional outcome trajectory from 6 to 24 months post‐surgery, aiding in rehabilitation programming and return‐to‐sport decisions to improve surgical outcomes and reduce the risk of reinjury. Level of evidenceLevel II.

Predicting anterior cruciate ligament failure load with T2* relaxometry and machine learning as a prospective imaging biomarker for revision surgery

“…However, translating these structural property prediction models to human patients and establishing their clinical relevance was necessary. In one of our studies, we showed that estimated failure load from Constructive Interference in Steady State scans (using a different prediction model) was significantly associated with functional outcomes for patients after the ACL restoration procedure 29 . To our knowledge, the present analysis is the first to show that the T 2 * relaxometry-based structural property predictions are associated with the incidence of revision surgery and is a critical step towards translating the large body of preclinical work that we have pursued.…”

Reinjury Following Return to Play

“…Using qMRI parameters of ACLR crosssectional area, ligament volume, and estimated failure load, Flannery et al found that these measurements at 6 months were predictive of positive functional outcome at 24 months, suggesting that a larger, stronger ligament as determined by qMRI at 6 months indicates greater functional recovery over the following 18 months. 56 Upper Extremity, Meniscal, and Osseous Reinjury Shoulder Shoulder injuries are common in elite baseball athletes, tennis players, swimmers, and football quarterbacks. 57 The type of injuries that occur in each sport is unique with different rehabilitation periods and reinjury patterns after RTP.…”

“…Using qMRI parameters of ACLR cross-sectional area, ligament volume, and estimated failure load, Flannery et al found that these measurements at 6 months were predictive of positive functional outcome at 24 months, suggesting that a larger, stronger ligament as determined by qMRI at 6 months indicates greater functional recovery over the following 18 months. 56…”

Postoperative Return to Play and the Role of Imaging

“…35,37,40,43 In addition, the surgically repaired tendon has a decreased risk of rerupture and an accelerated return to sport compared with nonoperative intervention. 31,37,40,43 Multiple operative interventions for Achilles repair are available, including open and minimally invasive procedures. Both open and minimally invasive repairs involve suturing the tendon back together; however, whereas in an open repair the tendon fibers can be sutured directly together, particularly if the tear is small, minimally invasive repair does not involve a direct end-to-end repair.…”

“…Using a constructive interference in steady state sequence, studies have demonstrated an ability to calculate a cross-sectional area and volume of the ACL graft, both of which were shown to correlate with a positive change in single-hop ratio results from 6 to 24 months. 31 Although such techniques require time-intensive segmentation of the graft with specialized software, it suggests additional data that MRI can provide in the prognostication and determination of RTP.…”