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.