Tight medial knot tying may increase retearing risk after transosseous equivalent repair of rotator cuff tendon

Article type: Research Article

Authors: Sano, Hirotaka^{a; *} | Tokunaga, Masako^a | Noguchi, Moriyuki^a | Inawashiro, Takashi^a | Irie, Taichi^a | Abe, Hiroo^a | Yokobori Jr, A. Toshimitsu^b

Affiliations: [a] Division of Orthopedics, Sendai City Hospital, Sendai, Japan | [b] Strategic Innovation Research Hub Laboratory of Strength of Materials and Science, Teikyo University, Tokyo, Japan

Correspondence: [*] Corresponding author: Hirotaka Sano, Senior Staff, Division of Orthopedics, Sendai City Hospital, 1-1-1, Asuto-Nagamachi, Taihaku-ku, Sendai, 982-8502, Japan. Tel.: +81-22-308-7111; Fax: +81-22-308-7153; E-mail: [email protected].

Abstract: Background:Retearing mechanism after transosseous equivalent (TOE) rotator cuff repair has not been fully clarified yet. Objective:The purposes of this study were to compare the stress distribution pattern in the tendon stump between knotted and knotless TOE repair and to investigate the role of suture tension applied during medial knot tying using a 3-dimensional finite element (3D-FE) method. Methods:Both knotted and knotless TOE repairs were simulated on the 3D-FE human rotator cuff tear model. Elastic analysis was performed to compare the stress distribution pattern inside the tendon between the two models. The amount of compressive load applied to the medial-row sutures was then changed as 0, 20, 40, 60, 80, and 100 N in the knotted model. Results:Knotted model demonstrated more distinct stress concentration inside the tendon around medial-row sutures than the knotless model. Mean von Mises equivalent stress in this area in the 0, 20, 40, 60, 80, and 100 N models was 0.26, 0.35, 0.50, 0.70, 1.11, and 1.14 MPa, respectively. Conclusions:In the knotted TOE repair, tight medial knot tying might cause a high stress concentration around medial knots, which may constitute one of the pathogenetic factors of postoperative retearing at this site.

Keywords: Rotator cuff tear, transosseous equivalent repair, medial knot tying, retearing, stress concentration, finite element method

DOI: 10.3233/BME-171673

Journal: Bio-Medical Materials and Engineering, vol. 28, no. 3, pp. 267-277, 2017