Mechanical properties of all-suture anchors for rotator cuff repair

Abstract

ObjectivesAll-suture anchors are increasingly used in rotator cuff repair procedures. Potential benefits include decreased bone damage. However, there is limited published evidence for the relative strength of fixation for all-suture anchors compared with traditional anchors.Materials and MethodsA total of four commercially available all-suture anchors, the ‘Y-Knot’ (ConMed), Q-FIX (Smith & Nephew), ICONIX (Stryker) and JuggerKnot (Zimmer Biomet) and a traditional anchor control TWINFIX Ultra PK Suture Anchor (Smith & Nephew) were tested in cadaveric human humeral head rotator cuff repair models (n = 24). This construct underwent cyclic loading applied by a mechanical testing rig (Zwick/Roell). Ultimate load to failure, gap formation at 50, 100, 150 and 200 cycles, and failure mechanism were recorded. Significance was set at p < 0.05.ResultsOverall, mean maximum tensile strength values were significantly higher for the traditional anchor (181.0 N, standard error (se) 17.6) compared with the all-suture anchors (mean 133.1 N se 16.7) (p = 0.04). The JuggerKnot anchor had greatest displacement at 50, 100 and 150 cycles, and at failure, reaching statistical significance over the control at 100 and 150 cycles (22.6 mm se 2.5 versus 12.5 mm se 0.3; and 29.6 mm se 4.8 versus 17.0 mm se 0.7). Every all-suture anchor tested showed substantial (> 5 mm) displacement between 50 and 100 cycles (6.2 to 14.3).All-suture anchors predominantly failed due to anchor pull-out (95% versus 25% of traditional anchors), whereas a higher proportion of traditional anchors failed secondary to suture breakage.ConclusionWe demonstrate decreased failure load, increased total displacement, and variable failure mechanisms in all-suture anchors, compared with traditional anchors designed for rotator cuff repair. These findings will aid the surgeon’s choice of implant, in the context of the clinical scenario.Cite this article: N. S. Nagra, N. Zargar, R. D. J. Smith, A. J. Carr. Mechanical properties of all-suture anchors for rotator cuff repair. Bone Joint Res 2017;6:82–89. DOI: 10.1302/2046-3758.62.BJR-2016-0225.R1

All-suture anchor pullout results in decreased bone damage and depends on cortical thickness

“…Before the inserter was removed, the insertion angle was cross-checked with a goniometer measuring the angle between the bone surface and the inserter of the anchor. A clamp to anchor distance of 10 cm was chosen, as previously published [20]. Since the load was not applied by the cuff muscle but by the threads aligned in their loading direction, the humeral head was protected by a plastic cover.…”

Comparison of Clinical and Functional Results After Arthroscopic Bankart Repair With The Conventional Metal Anchor and The All-Soft Suture Anchor

“…The authors compared 12 fresh-frozen human shoulders that underwent all suture anchors repair to 12 that underwent conventional anchors repair. They demonstrated that decreased failure load, increased total displacement, and variable failure mechanisms in all-suture anchors and also concluded that their findings will aid the surgeons choice of implant, in the context of the clinical scenario (14). In addition, compared to other conventional suture anchors, (9).…”

“…Although arthroscopic surgery suture anchors continue to evolve, the complications of bankart repair have not been completely solved (6,(20)(21)(22)(23). Metal suture anchor fixation is frequently used although it causes complications such as arthritis, pull-out, and osteolysis (10,11,14). Furthermore, several problems occur with anchor practice in labral repair (21,22).…”

The Effect of Three Different Suture Anchors for Rotator Cuff Repair on Primary Cultures of Human Bone Marrow Mesenchymal Stem Cells

“… 3 In particular, a growing interest has been recently focused on the biomechanical properties of different types of suture anchors used for rotator cuff repair concerning their stress resistance and suture configurations. 4 5…”