MRI evaluation of graft maturation following arthroscopic anatomical lateral ligament reconstruction: a one-year follow-up study.

Background: Chronic lateral ankle instability (CLAI) occurs in 20% to 40% of patients after lateral ankle sprains. Anatomical ligament reconstruction is increasingly used, but magnetic resonance imaging (MRI) evaluation of graft maturation-standard in anterior cruciate ligament (ACL) reconstruction-remains poorly defined for the ankle.

Purpose: To evaluate graft incorporation and ligamentization one year after arthroscopic anatomical reconstruction of the anterior talo-fibular ligament (ATFL) and calcaneo-fibular ligament (CFL) using autologous gracilis tendon grafts.

Study design: Prospective case series.

Methods: We included 93 patients with CLAI unresponsive to conservative treatment who underwent ATFL/CFL reconstruction with an autologous gracilis graft. MRI was performed at one year postoperatively. Graft maturation was assessed using the Signal-to-Noise Quotient Ankle (SNQA) and the Howell scale. Graft incorporation was evaluated via signal intensity at the bone-graft interface. Additional analysis included graft continuity, tunnel positioning, and diameter.

Results: Howell grade was ≤2 in 42% of ATFL and 80% of CFL grafts. Mean SNQA was 39.25 ± 159.89 for ATFL and 17.44 ± 80.01 for CFL. Graft incorporation (interface signal grade 1 or 2) was seen in 74% of talar tunnels, 90% of calcaneal tunnels, and 87% of fibular tunnels. All grafts were continuous; no intra-articular complications were identified.

Conclusion: Anatomical reconstruction of the ATFL/CFL with gracilis autografts leads to good graft incorporation and ligamentization at one year. MRI parameters described here offer a reproducible evaluation framework, although correlation with functional outcomes remains necessary.