Biomechanical Comparison of an Open Vs Arthroscopic Approach for Lateral Ankle Instability

Background: The current clinical standard for the surgical treatment of ankle instability remains the open modified Broström procedure. Modern advents in arthroscopic technology have allowed physicians to perform certain foot and ankle procedures arthroscopically as opposed to traditional open approaches.

Methods: Twenty matched lower extremity cadaver specimens were obtained. Steinman pins were inserted into the tibia and talus with 6 sensors affixed to each pin. Specimens were placed in a Telos ankle stress apparatus in an anteroposterior and then lateral position, while a 1.7 N-m load was applied. For each of these tests, movement of the sensors was measured in 3 planes using the Optotrak Computer Navigation System. Changes in position were calculated and compared with the unloaded state. The anteriortalofibular ligament and the calcaneofibular ligament were thereafter sectioned from the fibula. The aforementioned measurements in the loaded and unloaded states were repeated on the specimens. The sectioned ligaments were then repaired using 2 corkscrew anchors. Ten specimens were repaired using a standard open Broström-type repair, while the matched pairs were repaired using an arthroscopic technique. Measurements were repeated and compared using a paired t test.

Results: There was a statistically significant difference between the sectioned state and the other 3 states (P < .05). There were no statistically significant differences between the intact state and either the open or arthroscopic state (P > .05). There were no significant differences between the open and arthroscopic repairs with respect to translation and total combined motion during the talar tilt test (P > .05). Statistically significant differences were demonstrated between the 2 methods in 3 specific axes of movement during talar tilt (P = .04).

Conclusion: Biomechanically effective ankle stabilization may be amenable to a minimally invasive approach.

Clinical Relevance: A minimally invasive, arthroscopic approach can be considered for treating patients with lateral ankle instability who have failed conservative treatment.