Repair of the Ankle Syndesmosis: A Biomechanical of Analysis of Three Current Repair Techniques. Issue 7 (18th July 2016)

• Record Type: Journal Article
• Authors: Backus, Jonathan D.; Clanton, Thomas O.; Whitlow, Scott R.; Williams, Brady T.; Liechti, Daniel; Dornan, Grant J.; Saroki, Adriana; Turnbull, Travis Lee; LaPrade, Robert F.
• Is Part Of: Orthopaedic journal of sports medicine. Volume 4:Issue 7(2016.)Supplement 4
• Publication Date: 2016-07-18
• Subjects: Sports medicine -- Periodicals; Orthopedics -- Periodicals; Arthroscopy -- Periodicals; Arthroplasty -- Periodicals; Knee -- Surgery -- Periodicals; 616.7
• DOI: 10.1177/2325967116S00173
• Languages: English
• ISSNs: 2325-9671

Abstract

Objectives: Significant debate exists regarding the optimal repair techniques for unstable syndesmosis injuries. Techniques range from one to multiple screw fixation, suture-button fixation devices, or a combination of the two. The purpose of the current investigation was to biomechanically compare three common syndesmotic repair techniques using a simulated weight-bearing protocol with internal and external rotation of the foot. Methods: Twenty-four, lower leg specimens with mean age 54.25 years (range, 38 to 68 years) were utilized for testing. Following the creation of a complete syndesmotic injury (AITFL, ITFL, PITFL, interosseous membrane) specimens were repaired using one of three randomly assigned repair techniques: (1) one 3.5 mm syndesmotic screw, (2) one suture-button construct, and (3) two divergent suture-button constructs. For testing, specimens were oriented in neutral plantar/dorsiflexion and neutral internal/external rotation with the respect to the vertical tibia. Repairs were then cycled for 500 cycles between 7.5 Nm of internal/external rotation torque under a constant 750 N axial compressive load. At 0, 10, 100, and 500 cycles, torsional cyclic loading was interrupted to assess torsional stiffness and resistance to rotation within a physiologic range of motion. While axially loaded to 750 N, the foot was externally rotated to 15° and then rotated to 10° of internal rotation. Torsional cyclic loading was then resumed. Torque (Nm) and rotational position (degrees) were recorded continuously throughout testing. Three-dimensional data was also collected throughout testing to characterize the relative spatial relationships of the tibiofibular articulation. Results: Biomechanically, there were no significant differences between techniques when repairs were compared to the intact syndesmosis. Three-dimensional analysis revealed significant differences between all repair techniques for sagittal fibular translation with external rotation of the foot. Screw fixation had the smallest magnitude in sagittal translation (-2.5 mm), and a single suture-button construct demonstrated the largest magnitude of sagittal translation (-4.6 mm). Screw fixation also allowed for significantly lower sagittal translation with internal rotation of the foot (0.1 mm) when compared to both one (2.7 mm) and two (2.9 mm) suture-button repair constructs. Conclusion: All repairs provided a significant resistance to internal and external rotation, and only demonstrated mild reductions in strength and torsional stiffness throughout torsional cyclic testing.