Research Article| Volume 62, ISSUE 1, P45-49, January 2023

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Biomechanical Comparison of Knotless Suture Anchor Versus Percutaneous End-to-End Technique for Mid-Substance Achilles Tendon Rupture Repair

  • Colin P. Murphy
    Department of Graduate Medical Education, Sanford Health, Fargo, ND

    University of North Dakota, School of Medicine & Health Sciences, Grand Forks, ND

    Sanford Orthopedics & Sports Medicine – Sanford Health, Fargo, ND
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  • Tyler J. Safgren
    University of North Dakota, School of Medicine & Health Sciences, Grand Forks, ND

    Sanford Orthopedics & Sports Medicine – Sanford Health, Fargo, ND
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  • Eric T. Piatt
    Sanford Orthopedics & Sports Medicine – Sanford Health, Fargo, ND
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  • Alexander C.M. Chong
    Address correspondence to: Alexander Chong, MSAE, MSME, Lead Research Engineer, Department of Graduate Medical Education - Sanford Health, 1720 University Drive South, Route 1895, Fargo, ND 58103.
    Department of Graduate Medical Education, Sanford Health, Fargo, ND

    University of North Dakota, School of Medicine & Health Sciences, Grand Forks, ND
    Search for articles by this author
  • Bruce E. Piatt
    Department of Graduate Medical Education, Sanford Health, Fargo, ND

    University of North Dakota, School of Medicine & Health Sciences, Grand Forks, ND

    Sanford Orthopedics & Sports Medicine – Sanford Health, Fargo, ND
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Published:April 01, 2022DOI:


      Percutaneous Achilles tendon repairs can be performed with 2 distal fixation techniques: knotless suture anchor repair (KL) or percutaneous end-to-end repair (ETE). There is a paucity of literature comparing the biomechanical strength of these 2 distal fixation techniques. The aim of this study was to compare the strength of KL and ETE repairs using flat-braided suture for mid-substance Achilles tendon rupture during simulated progressive rehabilitation. Nine matched pairs of fresh-frozen below-knee cadaveric extremities were randomly assigned into these 2 repair groups. Each specimen was tested in 2 parts sequentially; Part I simulating passive ankle range of motion (cyclic: 20N-100N), and Part II simulating ambulation in a walking boot (cyclic: 20N-190N). The number of cycles, gap displacement, and the mode of failure were recorded for each repair. Achilles tendon repairs using the percutaneous methods of ETE and KL techniques showed no significant difference in the number of cycles to clinical failure, mean gap displacement, or overall failure rate. During Part I, the survival rate in terms of clinical failure for KL and ETE groups was 8 of 9 repairs and 7 of 9 repairs, respectively. During Part II, all repairs experienced clinical failure in both groups. Five repairs in the KL group experienced suture anchor pull out from the calcaneus, and 3 repairs failed at suture-tendon interface. Four repairs in the ETE group failed due to knot slippage and 5 repairs failed at suture-tendon interface. Both techniques are viable options in treating acute mid-substance Achilles tendon ruptures.

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