SLR - October 2023 - Kaur
Title: The Biomechanical Role of the Deltoid Ligament on Ankle Stability: Injury, Repair, and AugmentationReference: Brady AW, Bryniarski A, Brown JR, et al. The biomechanical role of the deltoid ligament on ankle stability: Injury, repair, and augmentation. Am J Sports Med. 2023. 51(10):2617-2624.
Level of Evidence: Level 3
Reviewed By: Kushkaran Kaur, DPM
Residency Program: Temple University Hospital, Philadelphia, PA
Podiatric Relevance: This article aims to characterize the biomechanical role of the anterior and posterior deltoid ligament in ankle stability and provide evidence for the biomechanical strength of superficial and deep repair of the deltoid.
Methods: Ten cadaveric ankles were mounted on a robotic arm and underwent an anterior drawer test at 88 N, eversion at 5 Nm and external rotation at 5 Nm at 0 and 25 degrees of plantarflexion under 100 N of axial joint compression. The primary outcome measures were the amount of eversion, external rotation and anterior translation at the end of each test. State 1 was the control and included testing with all ligaments intact. State 2 was testing after sectioning of the superficial tibionavicular, tibiospring, tibiocalcaneal, and the deep anterior tibiotalar ligaments. State 3 was testing after sectioning of the anterior ligaments and then suture anchor repair of the anterior superficial and deep deltoid. State 4 included augmentation of the repair of the tibiocalcaneal ligament using suture tape. In state 5, the deep anterior tibiotalar ligament was repaired. State 6 involved sectioning of the superficial and deep posterior talotibial ligaments , leaving the anterior ligaments intact. In state 7, the posterior deltoid was repaired. Both of the anterior and posteriod deltoid ligaments were transected in State 8.
Results: Cutting the anterior deltoid caused statistically significant external rotation and eversion laxity compared to the native state at neutral and 25 degrees plantarflexion. The anterior deltoid repair and the tibiocalcaneal repair restored external rotation laxity at neutral and 25 degrees plantarflexion, however it did not restore eversion. Eversion was reduced with the anterior deltoid repair when the ankle was at 25 degrees of plantarflexion. The tibiocalcaneal augmentation reduced eversion at neutral and 25 degrees of ankle plantarflexion. The anterior tibiotalar repair did not provide further benefit to eversion and over-constrained external rotation at 25 degrees of plantarflexion compared with the native state. The posterior deltoid repair over-constrained anterior translation at neutral and 25 degrees of plantarflexion and external rotation at 25 degrees of plantarflexion. The posterior deltoid tear did not have significant differences in laxity compared to the group with the anterior repair of the tibiocalcaneal and tibiotalar ligaments. The complete deltoid tear showed laxity in all tests compared to the native state. Eversion laxity increased by 23-33.6 degrees compared to the native state.
Conclusions: There is significant laxity in eversion with a complete deltoid rupture and therefore primary repair should be performed. Primary repair of the anterior tibiotalar and tibiocalcaneal ligaments was sufficient with no additional benefits from posterior repair. In the setting of an anterior tear, anterior repair with tibiocalcaneal augmentation is preferred as tibiotalar repair over-constrains external rotation.