Quantitative imaging of anterior cruciate ligament (ACL) graft demonstrates longitudinal compositional changes and relationships with clinical outcomes at 2 years after ACL reconstruction

摘要

Abstract T 1 ρ and T 2 magnetic resonance imaging (MRI) may allow for a noninvasive assessment of ligamentization after anterior cruciate ligament (ACL) reconstruction. We hypothesized that ACL graft T 1 ρ and T 2 relaxation times would decrease over time, that T 1 ρ and T 2 relaxation times would be inversely correlated with Knee Osteoarthritis Outcome Scores (KOOS), and that T 1 ρ and T 2 values would be lower for autograft relative to allograft reconstruction. Thirty‐nine patients (age: 30.5?±?8.2 years) were followed prospectively after ACL reconstruction with hamstring autograft (N?=?27) or soft‐tissue allograft (N?=?12). Magnetic resonance (MR) imaging and KOOS surveys were completed at 6, 12, 24, and 36 months after surgery. ACL graft was segmented to define T 1 ρ and T 2 relaxation times. Relaxation times were compared between time points with ANOVA tests. Log‐transformed autograft and allograft relaxation times were compared with the Student t tests. The relationship between KOOS and relaxation times at 24 months was investigated with Spearman's rank correlation. ACL graft T 1 ρ relaxation times were significantly higher at 6 months relative to 12 months ( P ?=?.042), 24 months ( P ??.001), and 36 months ( P ??.001). ACL graft T 2 relaxation times were significantly higher at 6 months relative to 12 months ( P ?=?.036), 24 months ( P ??.001), and 36 months ( P ??.001). T 1 ρ and T 2 relaxation times were significantly lower for autograft reconstruction vs allograft reconstruction at 24 months postreconstruction. Two‐year KOOS Sports, Pain, and Symptoms were significantly inversely correlated with T 1 ρ and T 2 relaxation times. T 1 ρ and T 2 sequences may offer a noninvasive method for monitoring ACL graft maturation that correlates with patient‐reported knee function after ACL reconstruction.