Cartilage Matrix Degeneration Occurs within the First Year after ACLR and Is Associated with Impaired Clinical Outcome

Abstract

Objective Anterior cruciate ligament reconstruction (ACLR) has not been shown to decrease the risk for development of post-traumatic osteoarthritis. Magnetic resonance imaging (MRI) T2 mapping can be used to assess cartilage compositional changes. This study tests whether (1) worse cartilage arthroscopic status at ACLR is reflected by higher cartilage T2 values in matched study regions 6 weeks and 1 year after ACLR, and (2) increasing cartilage T2 values between 6 weeks and 1 year after ACLR are associated with worsening patient-reported outcomes. Design Twenty-two participants with ACLR and 26 controls underwent 3T MRI. T2 values in medial and lateral femoral and tibial cartilage were measured at 6 weeks and 1 year after ACLR and compared with arthroscopic grades, Knee injury and Osteoarthritis Outcome Scores (KOOS), and control T2 values. Results Most (59%-86%) cartilage study regions examined by arthroscopy demonstrated intact articular surfaces. Average T2 value increased in 3 of 4 study regions between 6 weeks and 1 year after ACLR ( P = .001-.011). T2 value increased ( P < .013) even for participants whose cartilage had intact articular surfaces at ACLR. Participants with ACLR who showed greater increases in cartilage T2 values had less improvement to KOOS Quality of Life ( P = .009, ρ = −0.62). Discussion Cartilage status assessed arthroscopically at ACLR and by MRI T2 maps 6 weeks later was healthier than cartilage status assessed by MRI T2 maps at 1-year follow-up. Progressive T2 elevations were observed over the first year after ACLR even in patients with arthroscopically intact cartilage at the time of surgery and were associated with reduced improvement in knee quality of life suggesting preosteoarthritis.

Clinical validation of fully automated laminar knee cartilage transverse relaxation time (T2) analysis in anterior cruciate ligament (ACL)-injured knees— on behalf of the osteoarthritis (OA)-Bio consortium

“…Yet, in some studies of patients with acute ACL injuries, alterations in cartilage T2 were described relatively early after the event ( 55 ), and were maintained up to 6 years after ACL surgery ( 56 ). A greater (increase of) T2 relative to the unaffected contralateral knee ( 57 ) or healthy control knees ( 58 ) was found to be associated with worse patient-reported outcomes after surgical ACL reconstruction. Further, biomechanical factors, including knee muscular strength deficits, and altered knee joint movement and loading patterns ( 59 - 62 ), have been shown to account for a substantial proportion of knee cartilage T2 variation observed after ACL surgery, and T2 lesions were predicted by subject-specific computations of cartilage stress using finite element modeling ( 63 ).…”

Femoral cartilage ultrasound echo‐intensity is a valid measure of cartilage composition

“…[8][9][10] Additionally, early measures of cartilage composition are related to future declines in patient reported and functional outcomes following ACLR. [11][12][13][14] Despite the potential importance of MR-derived outcomes of cartilage composition as an early prognostic biomarker of OA, there are limitations in cost, accessibility, and technical expertise that prevent the widespread use of advanced compositional imaging techniques outside of well-funded research environments.…”

Quantitative Magnetic Resonance Imaging of Lateral Compartment Articular Cartilage After Lateral Extra-articular Tenodesis

“…§ § Changes in tibiofemoral cartilage relaxation times have been detected using T1rho and T2 quantitative MRI within the first 2 years after ACLR. 51,56,58 To our knowledge, no studies have compared the effect of augmenting ACLR with LET on cartilage matrix composition compared with ACLR alone.…”