The Effect of Suture Caliber and Number of Core Strands on Repair of Acute Achilles Ruptures

Category: Sports Introduction/Purpose: Controversy exists in Achilles rupture management with options ranging from nonoperative care to open surgical repair. Current literature suggests re-rupture rates are lower with operative repair; therefore, surgery is recommended for active populations. The effect of suture caliber or number of core stands has not been studied in Achilles repair. Varying these factors may allow for a construct capable of earlier weight-bearing and rehabilitation. We hypothesized the number of core strands and suture caliber used in Achilles repair would significantly affect strength and gapping during a simulated early rehabilitation protocol. Methods: Sixteen cadaveric human foot and ankle specimens with no prior injuries or surgeries were utilized. Simulated midsubstance Achilles ruptures were created 6 cm proximal to the calcaneal insertion in 13 ankles. Specimens were randomly allocated to 1 of 4 groups: (1) intact Achilles tendon, (2) open repair using No. 2 suture with four core sutures and two 2mm suture-tape core sutures, (3) open repair using No. 2 suture with two core sutures and four 2mm suture-tape core sutures, and (4) open repair using No. 2-0 suture with 12 core sutures. Repairs consisted of three modified Kessler sutures and an epitenon stitch with a 3-0 monofilament suture. Specimens were subjected to a cyclic loading protocol simulating early, progressive postoperative rehabilitation: 250 cycles at 1 Hz for each loading range: 20-100, 20-200, 20-300, and 20-400 N. A 1-way ANOVA was used to test significance among repair groups. Results: During biomechanical testing, all repairs survived the first two loading stages. However, elongation trends during stage 1 (Figure 1) were consistent among subsequent cyclic loading stages. No significant elongation differences were observed between any of the repair groups (Groups 2-4), with mean displacements of 4.94 ± 0.90 mm, 3.93 ± 0.92 mm, and 5.35 ± 0.34 mm, respectively, at the end of the first loading stage. In Group 2, one repair failed during the fourth stage and 4 survived all four stages. In Group 3, one repair failed during the third stage and two repairs during the fourth stage. In Group 4, two repairs failed during the fourth stage and two survived all four stages. The average number of cycles to failure for Groups 2-4 was 967, 783, and 940 cycles, respectively. Conclusion: In this study, all but one repair survived 750 cycles. This was superior to a 6 core strand repair with No. 2 suture similarly evaluated in a previous study (427 cycles). When 4 of 6 strands were substituted with suture-tape, repair gapping decreased initially; yet, these repairs failed earlier. Gapping in Groups 2 and 4 was similar to the previously evaluated repair; however, the number of cycles to failure was higher. Therefore, substituting suture-tape for 2 core strands or doubling the core strands with a smaller caliber suture may be biomechanically superior and allow for earlier return to function

3-D CT Analysis of Screw and Suture-Button Fixation for Syndesmosis Repair

Category: Sports. Introduction/Purpose: Historically, unstable injuries to the distal tibiofibular syndesmosis have been repaired with syndesmotic screws. However, newer repair techniques with inherently flexible implants, including suture-button constructs, may be less susceptible to malreduction and more reliably restore the native anatomy. The purpose of this study was to compare the anatomic accuracy of reduction between a syndesmotic screw and suture-button constructs for syndesmosis repair using a pre- injury and postoperative 3-D model assessment. We hypothesized significant differences would be observed among repair techniques and suture-button constructs would most accurately restore the pre-injury syndesmotic volume. Methods: Twelve matched pairs of cadaveric specimens were dissected to identify the syndesmotic ligaments. Specimens were imaged with CT prior to the creation of a complete syndesmosis injury. The disrupted syndesmosis of each specimen was subsequently reduced using one of three randomly assigned repair techniques: (1) tri-cortical syndesmosis screw (3.5 x 50 mm), (2) one suture-button construct and (3) two suture-button constructs. Specimens were imaged postoperatively with CT. 3-D models of all scans and tibiofibular joint space volumes were created to assess restoration of the native syndesmosis (Figure 1). Volumetric joint space measurements were made starting at the distal aspect of the tibiofibular articulation and extended proximally with four 1 cm sections measured separately. Results: For each of the three fixation methods, the adjusted least squares means for total post-operative volumes of the syndesmosis were significantly decreased relative to the intact state. Total overall decreases in volume compared to the intact state for the one suture-button construct, two suture-button constructs, and syndesmotic screw were -561 mm3, -964 mm3 and - 377 mm3, respectively. Fixation with one suture-button construct was not significantly different from screw or two suture-button fixations. However, the total decrease in volume was significantly greater with the two suture-button repair compared to screw fixation (p < .05). Conclusion: The most important finding of this study was that fixation with one suture-button construct was not significantly different from screw or two suture-button fixations. All repairs significantly reduced the volume of the syndesmosis postoperatively compared to the intact state. Fixation with two suture-buttons resulted in significantly greater decreased volume than screw fixation. The data from the present study suggests that syndesmotic over-compression at time zero, particularly when using multiple suture-button implants, may be another potential factor contributing to malreduction of syndesmosis injuries that deserves further investigation