Biomechanical Comparison of 3 Current Ankle Syndesmosis Repair Techniques.
BACKGROUND
Significant debate exists regarding optimal repair for unstable syndesmosis injuries. Techniques range from screw fixation, suture-button fixation, or a combination of the two. In this study, 3 common repairs were compared using a simulated weightbearing protocol with internal and external rotation of the foot.


METHODS
Twenty-four lower leg specimens with mean age 54 years (range, 38-68 years) were used for testing. Following creation of a complete syndesmotic injury (AITFL, ITFL, PITFL, interosseous membrane), specimens were repaired using 1 of 3 randomly assigned techniques: (1) one 3.5-mm syndesmotic screw, (2) 1 suture-button construct, and (3) 2 divergent suture-button constructs. Repairs were cycled for 500 cycles between 7.5 Nm of internal/external rotation torque under a constant 750 N axial compressive load in a neutral dorsiflexion position. At 0, 10, 100, and 500 cycles, torsional cyclic loading was interrupted to assess torsional resistance to rotation within a physiologic range of motion (15 degrees external rotation to 10 degrees internal rotation). Torque (Nm), rotational position (degrees), and 3-dimensional data were collected throughout the testing to characterize relative spatial relationships of the tibiofibular articulation.


RESULTS
There were no significant differences between repair techniques in resistance to internal and external rotation with respect to the intact syndesmosis. Three-dimensional analysis revealed significant differences between repair techniques for sagittal fibular translation with external rotation of the foot. Screw fixation had the smallest magnitude of posterior sagittal translation (2.5 mm), and a single suture-button construct demonstrated the largest magnitude of posterior sagittal translation (4.6 mm). Screw fixation also allowed for significantly less anterior sagittal translation with internal rotation of the foot (0.1 mm) when compared to both 1 (2.7 mm) and 2 (2.9 mm) suture-button constructs.


CONCLUSIONS
All repairs provided comparable rotational stability to the syndesmosis; however, no repair technique completely restored rotational stability and tibiofibular anatomic relationships of the preinjury state.


CONCLUSIONS
Constructs were comparable across most conditions; however, when repairing injuries with a suture-button construct, a single suture-button construct may not provide sufficient resistance to sagittal translation of the fibula.
1 Steadman Philippon Research Institute, Vail, CO, USA.|2 The Steadman Clinic, Vail, CO, USA.
Thomas O
TO
Clanton
1 Steadman Philippon Research Institute, Vail, CO, USA.|2 The Steadman Clinic, Vail, CO, USA.
Scott R
SR
Whitlow
1 Steadman Philippon Research Institute, Vail, CO, USA.
Brady T
BT
Williams
1 Steadman Philippon Research Institute, Vail, CO, USA.
Daniel J
DJ
Liechti
1 Steadman Philippon Research Institute, Vail, CO, USA.|2 The Steadman Clinic, Vail, CO, USA.
Jonathon D
JD
Backus
1 Steadman Philippon Research Institute, Vail, CO, USA.
Grant J
GJ
Dornan
1 Steadman Philippon Research Institute, Vail, CO, USA.
Adriana J
AJ
Saroki
1 Steadman Philippon Research Institute, Vail, CO, USA.
Travis Lee
TL
Turnbull
1 Steadman Philippon Research Institute, Vail, CO, USA.|2 The Steadman Clinic, Vail, CO, USA.
Robert F
RF
LaPrade
D000328:Adult; D000368:Aged; D016512:Ankle Injuries / Q000503:physiopathology / Q000601:surgery*; D000843:Ankle Joint / Q000503:physiopathology / Q000601:surgery*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D005360:Fibula / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D011897:Random Allocation; D016059:Range of Motion, Articular; D012399:Rotation; D053441:Suture Anchors; D013536:Suture Techniques
anterior inferior tibiofibular ligament; biomechanics; interosseous tibiofibular ligament; posterior inferior tibiofibular ligament; suture-button; syndesmosis screw