Biomechanical Comparison of All-Soft Suture Anchor Single-Row vs Double-Row Bridging Construct for Insertional Achilles Tendinopathy

Abstract

Background: Two common operative fixation techniques for insertional Achilles tendinopathy are the use of all-soft suture anchors vs synthetic anchors with a suture bridge. Despite increasing emphasis on early postoperative mobilization, the biomechanical profile of these repairs is not currently known. We hypothesized that the biomechanical profiles of single-row all-soft suture anchor repairs would differ when compared to double-row suture bridge repairs. Methods: Achilles tendons were detached from their calcaneal insertions on 6 matched-pair, fresh-frozen cadaver through-knee amputation specimens. Group 1 underwent a single-row repair with all-soft suture anchors. Group 2 was repaired with a double-row bridging suture bridge construct. Achilles-calcaneal displacement was tracked while specimens were cyclically loaded from 10 to 100 N for 2000 cycles and then loaded to failure. Linear mixed models were used to analyze the independent effects of age, body mass index, tendon morphology, repair construct, and footprint size on clinical and ultimate failure loads, Achilles-calcaneal displacement, and mode of failure. Results: The suture bridge group was independently associated with an approximately 50-N increase in the load to clinical failure (defined as more than 5 mm tendon displacement). There was no difference in ultimate load to failure or tendon/anchor displacement between the 2 groups. Conclusion: This cadaveric study found that a double-row synthetic bridge construct had less displacement during cyclic loading but was not able to carry more load before clinical failure when compared to a single-row suture anchor construct for the operative repair of insertional Achilles tendinopathy. Clinical Relevance: Our data suggest that double-row suture bridge constructs increase the load to clinical failure for operative repairs of insertional Achilles tendinopathy. It must be noted that these loads are well below what occurs during gait and the repair must be protected postoperatively without early mobilization. This study also identified several clinical factors that may help predict repair strength and inform further research.

A comparative study of single-vs. double-row technique in surgical treatment of insertional Achilles tendinopathy

“…For example, Beitzel et al (33) concluded that the double-row technique has a greater contact area and tolerates greater tension in stress testing than the single-row technique, which corroborates the results of a previous study by an orthopedic implant company (34) . However, a recent cadaver study (35) , as well as Pilson et al (36) , found that the double-row technique could not tolerate a greater load before failure.…”

Double-Row Achilles Insertional Repair With Rip-Stop Increases Construct Strength Compared to Traditional Techniques: A Biomechanical Study

“…15 Sutures tearing through tendon in biomechanics has historically been recognized as a common failure mode in both single-and double-row Achilles repairs. 2,6,8,14,18 However, this failure is not frequently seen clinically. Clinically, a complication repeatedly reported is postoperative superficial wound infection treated with antibiotics and debridement.…”

Treatment of Calcific Insertional Achilles Tendinopathy: Knotless Internal Brace versus Knot-Tying Suture Bridge

“…It has been shown that single-row repair is similar to the double-row suture bridge technique in terms of load to failure and cyclic displacement, which is not significantly associated with the size of the rotator-cuff rupture [ 20 ]. A biomechanical study found that the Achilles insertion repaired by the double-row technique had less displacement during cyclic loading but could not stand more load before clinical failure than single-row suture anchoring [ 6 ]. However, a meta-analysis consisting of eight biomechanical studies suggested that double-row repair is superior to single-row repair in load to failure and tear resistance in rotator cuffs [ 21 ].…”

“…The Achilles insertion is usually repaired by reattaching the tendon to the calcaneus using anchors and sutures. Suture anchors include single-row and double-row repair, which each have advantages and disadvantages in biomechanical properties [ 6 , 7 ]. The double-row suture bridge technique has been increasingly used in recent years.…”