Comparison of Several Suture Tape and Suture Button Constructs for Fixation of the Unstable Syndesmosis
2Orthopedic Surgery, Tokyo Medical and Dental University Medical Center, Japan
3Foot and Ankle Service, Massachusetts General Hospital, USA
Aims:
The purpose of this study was to arthroscopically evaluate syndesmotic stability following fixation with several combinations of suture buttons and suture tape reinforcement in a completely unstable cadaveric model.
Materials and Methods:
Fifteen cadaveric above-knee specimens underwent sequential ligament transection and fixation to create six experimental models: (1) intact model, (2) after complete disruption of the syndesmotic ligaments, and after repair with either suture tape reinforcement (3), suture tape reinforcement with a single suture button (4), suture tape reinforcement with two diverging suture buttons (5), or two diverging suture buttons alone (6). Instability measurements included anterior and posterior tibiofibular spaces measured arthroscopically under 100 N coronal stress, tibiofibular anteroposterior and posteroanterior translation in sagittal plane measured arthroscopically under sagittal stress of 100N and anterior tibiofibular space measured directly with a caliper under external rotation torque of 7.5 N m. Instability measurements taken after each fixation method were compared to the uninjured model and to the complete unstable model using the Wilcoxon signed-rank test.
Results:
Fixation using a combination of one suture button and singular suture tape reinforcement augmentation provided stability similar to the intact stage (coronal anterior space 1.24 vs 1.15, p=0.887; coronal posterior space 1.63 vs 1.64, p=0.8421; anteroposterior translation 0.91 vs 0.46, p=0.003; posteroanterior translation 0.51vs 0.57, p=0.051; external rotation anterior tibiofibular space 1.08 vs 0.55, p=0.069). Moreover, adding a second suture button led to further gains in fixation stability.
Discussion:
This study suggests that while a destabilizing syndesmotic injury that includes the AITFL, IOL, and PITFL is not adequately stabilized by either one or two suture buttons, the addition of a suture tape reinforcement to even one suture button restores syndesmotic stability to the pre-injury level.