Anterior talofibular ligament ruptures, part 2: biomechanical comparison of anterior talofibular ligament reconstruction using semitendinosus allografts with the intact ligament.

Abstract

Anatomic reconstructions of the lateral ankle ligaments with grafts have been proposed for patients with generalized ligamentous laxity, long-standing instability with attenuated native tissues, varus hindfoot misalignment, or failed prior lateral ligament surgery and for very large patients or elite athletes because of increased demands. Anatomic reconstruction of the anterior talofibular ligament (ATFL) using a semitendinosus allograft fixed with biocomposite interference fit screws would have similar biomechanical properties to the intact ATFL at time zero in a cadaveric model. Controlled laboratory study. Allograft reconstruction of the ATFL was performed in 6 fresh-frozen cadaveric ankles. The specimens were loaded to failure to determine the strength and stiffness of the reconstruction and compared with data from 6 cadaveric specimens with intact ATFLs. The mean ultimate load to failure of the allograft reconstruction (170.7 ± 54.8 N) was not significantly different from that of the intact ATFL (154.0 ± 63.7 N). The mean stiffness of the allograft reconstruction (23.1 ± 9.3 N/mm) was also not significantly different from that of the intact ATFL (14.5 ± 4.4 N/mm). Anatomic reconstruction of the ATFL with allografts demonstrated similar strength and stiffness to the native ligament at time zero in a fresh-frozen cadaveric model. This technique of anatomic reconstruction of the ATFL with allografts has biomechanical validation for use in clinical situations where a Broström repair of the lateral ankle ligaments is unlikely to be successful or has previously failed.