Advertisement

Suture Slippage in Knotless Suture Anchors as a Potential Failure Mechanism in Rotator Cuff Repair

Published:September 17, 2012DOI:https://doi.org/10.1016/j.arthro.2012.04.150

      Purpose

      To quantify the strength of suture fixation of knotless suture anchors in relation to the anchors' pullout strength and to compare these results with the static friction between different sutures and anchor materials.

      Methods

      Suture slippage within the anchor and pullout strength of 4 different knotless suture anchor models were assessed in a bovine bone model. Furthermore, the peak force before onset of slippage of different sutures trapped between increasingly loaded 4-mm rods made of commonly used anchor material (polyetheretherketone, poly-L-lactide acid, metal) was assessed.

      Results

      In all but 1 of the tested anchors, there was a relevantly lower load needed for slippage of the sutures than to pull out the anchor from bone. The mean load to anchor pullout ranged between 156 and 269 N. The load to suture slippage ranged between 66 and 109 N. All sutures were better held between the metal rods (mean, 21; 95% confidence interval [CI], 19.2 to 23.3) than with polyetheretherketone rods (mean, 17; 95% CI, 15.7 to 18.1) or poly-L-lactide acid rods (mean, 18; 95% CI, 17.6 to 18.4).

      Conclusions

      In the case of suture anchors that hold the sutures by clamping, the hold of the suture in the anchor may be far lower than the pullout strength of the anchor from bone, because the sutures just slip out from the anchor through the clamping mechanism. This is well explained by the low static friction achieved between the tested sutures and the test rods made of anchor materials.

      Clinical Relevance

      The use of knotless suture anchors appears quick and easy to perform; however, most of the anchor systems could not even reach half of the anchor pullout strength from bone before suture slippage occurred.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Arthroscopy
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Barber F.A.
        • Herbert M.A.
        • Beavis R.C.
        • Barrera Oro F.
        Suture anchor materials, eyelets, and designs: Update 2008.
        Arthroscopy. 2008; 24: 859-867
        • Barber F.A.
        • Hapa O.
        • Bynum J.A.
        Comparative testing by cyclic loading of rotator cuff suture anchors containing multiple high-strength sutures.
        Arthroscopy. 2010; 26: 134-141
        • Barber F.A.
        • Herbert M.A.
        • Hapa O.
        • et al.
        Biomechanical analysis of pullout strengths of rotator cuff and glenoid anchors: 2011 update.
        Arthroscopy. 2011; 27: 895-905
        • Burkhart S.S.
        A stepwise approach to arthroscopic rotator cuff repair based on biomechanical principles.
        Arthroscopy. 2000; 16: 82-90
        • Wright P.B.
        • Budoff J.E.
        • Yeh M.L.
        • Kelm Z.S.
        • Luo Z.P.
        Strength of damaged suture: An in vitro study.
        Arthroscopy. 2006; 22: 1270-1275
        • Bisson L.J.
        • Manohar L.M.
        A biomechanical comparison of the pullout strength of No. 2 FiberWire suture and 2-mm FiberWire tape in bovine rotator cuff tendons.
        Arthroscopy. 2010; 26: 1463-1468
        • Park M.C.
        • ElAttrache N.S.
        • Tibone J.E.
        • Ahmad C.S.
        • Jun B.J.
        • Lee T.Q.
        Part I: Footprint contact characteristics for a transosseous-equivalent rotator cuff repair technique compared with a double-row repair technique.
        J Shoulder Elbow Surg. 2007; 16: 461-468
        • Maguire M.
        • Goldberg J.
        • Bokor D.
        • et al.
        Biomechanical evaluation of four different transosseous-equivalent/suture bridge rotator cuff repairs.
        Knee Surg Sports Traumatol Arthrosc. 2011; 19: 1582-1587
        • Leedle B.P.
        • Miller M.D.
        Pullout strength of knotless suture anchors.
        Arthroscopy. 2005; 21: 81-85
        • Tompkins M.
        • Monchik K.O.
        • Plante M.J.
        • Fleming B.C.
        • Fadale P.D.
        Contact area and pressure in suture bridge rotator cuff repair using knotless lateral anchors.
        Knee Surg Sports Traumatol Arthrosc. 2011; 19: 1788-1793
        • Kaplan K.
        • ElAttrache N.S.
        • Vazquez O.
        • Chen Y.J.
        • Lee T.
        Knotless rotator cuff repair in an external rotation model: The importance of medial-row horizontal mattress sutures.
        Arthroscopy. 2011; 27: 471-478
        • Busfield B.T.
        • Glousman R.E.
        • McGarry M.H.
        • Tibone J.E.
        • Lee T.Q.
        A biomechanical comparison of 2 technical variations of double-row rotator cuff fixation: The importance of medial row knots.
        Am J Sports Med. 2008; 36: 901-906
        • Pietschmann M.F.
        • Gülecyüz M.F.
        • Fieseler S.
        • et al.
        Biomechanical stability of knotless suture anchors used in rotator cuff repair in healthy and osteopenic bone.
        Arthroscopy. 2010; 26: 1035-1044
        • Suchenski M.
        • McCarthy M.B.
        • Chowaniec D.
        • et al.
        Material properties and composition of soft-tissue fixation.
        Arthroscopy. 2010; 26: 821-831
        • Bisson L.J.
        • Manohar L.M.
        • Wilkins R.D.
        • Gurske-Deperio J.
        • Ehrensberger M.T.
        Influence of suture material on the biomechanical behavior of suture-tendon specimens: A controlled study in bovine rotator cuff.
        Am J Sports Med. 2008; 36: 907-912