Initial stability and stress distribution of ankle arthroscopic arthrodesis with three kinds of 2-screw configuration fixation: a finite element analysis.
BACKGROUND
Arthroscopic ankle arthrodesis (AAA) is recognized as the standard treatment for the end-stage ankle arthritis. Two-screw configuration fixation is a typical technique for AAA; however, no consensus has been reached on how to select most suitable inserted position and direction. For better joint reduction, we developed a new configuration (2 home run-screw configuration: 2 screws are inserted from the lateral-posterior and medial-posterior malleolus into the talar neck) and investigated whether it turned out to be better than the other commonly used 2-screw configurations.


METHODS
In this study, we investigated three kinds of 2-screw configurations: 2 "home run"-screw configuration (group A), crossed transverse configuration (the screw is inserted from the medial malleolus into the anterior talus and the other from the lateral tibia maintains posterior talus, group B), and 2 parallel screw configuration (2 parallel screws are inserted from the posteromedial side of the tibia into talus, group C). The effects of the above three insertions on the loading stress of the tibio-talar joint were comparatively analyzed with a three-dimensional finite element model.


RESULTS
Group A was better than groups B and C in respect of stress distribution uniformity and superior to both groups B and C in anti-flexion strength and anti-internal rotation strength. Group A was slightly worse than group C but better than group B in anti-dorsiflexion and anti-valgus and varus strength.


CONCLUSIONS
Two "home run"-screw configuration facilitates the reduction of anterior talus dislocation of end-stage ankle arthritis. Our finite element analysis demonstrates the configuration is superior to crossed transverse and parallel configuration for arthroscopic ankle arthrodesis in terms of stress distribution and initial stability.
['Zhu|Min|M|', 'Yuan|Cheng-Song|CS|', 'Jin|Zhong-Min|ZM|', 'Wang|Yun-Jiao|YJ|', 'Shi|You-Xing|YX|', 'Yang|Zhi-Jin|ZJ|', 'Tang|Kanglai|K|']
D000328:Adult D000843:Ankle Joint D001168:Arthritis D001174:Arthrodesis D001863:Bone Screws D020342:Finite Element Analysis D006801:Humans D021621:Imaging, Three-Dimensional D007593:Joint Instability D008297:Male D013314:Stress, Mechanical D013977:Tibia D014057:Tomography, X-Ray Computed D016474:Weight-Bearing
Ankle Arthrodesis Finite element analysis Arthritis Arthroscopy