MRI assessment of graft maturation after arthroscopic anatomical lateral ankle ligament reconstruction: One-year comparison between autograft and allograft.

BACKGROUND

Chronic lateral ankle instability (CLAI) is a common condition often requiring surgical reconstruction of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL). While autografts are traditionally used, allografts are gaining interest due to reduced donor site morbidity. This study aimed to compare graft maturation between autograft and allograft using a multimodal MRI evaluation at one year.

METHODS

This prospective, monocentric cohort study included 36 patients who underwent anatomical reconstruction of the ATFL and CFL between December 2020 and December 2023, using either gracilis autograft (n = 18) or frozen, non-irradiated allograft (n = 18). MRI performed at 8-15 months postoperatively assessed graft integration using three parameters: Signal-to-Noise Quotient Ankle (SNQA), Howell maturity score, and graft-to-bone interface signal. Measurements were performed independently by two blinded observers. Statistical comparison between groups was conducted using Mann-Whitney tests, and interobserver reproducibility was assessed using intraclass correlation coefficients (ICC).

RESULTS

Interobserver reliability was excellent for SNQA (ICC = 0.976 for ATFL, ICC = 0.895 for CFL). No statistically significant differences were observed between autografts and allografts for any parameter: SNQA (ATFL, p = 0.267; CFL, p = 0.494), Howell score (ATFL, p = 0.436; CFL, p = 0.083), or graft-to-bone interface (talus, p = 0.332; calcaneus, p = 0.752; fibula, p = 0.289).

CONCLUSION

At one year, MRI-based maturation of autografts and allografts in anatomical lateral ankle ligament reconstruction was equivalent across all evaluated criteria. These findings support the use of allograft as a reliable alternative to autograft, particularly in selected patients where autograft harvesting is undesirable. Further longitudinal and functional outcome studies are warranted.