Yoshinari Sakaki1,2, Keigo Taniguchi3, Fumiko Sato1, Naoki Oikawa4, Masaki Katayose2, Hideji Kura5, Kenji Okamura5. 1. Department of Rehabilitation, Hitsujigaoka Hospital, 3-1-10 Aoba-cho, Atsubetsu-ku, Sapporo, Hokkaido, 004-0021, Japan. 2. Second Division of Physical Therapy, School of Health Sciences, Sapporo Medical University, West 17, South 1, Chuo-ku, Sapporo, Hokkaido, 060-8556, Japan. 3. Second Division of Physical Therapy, School of Health Sciences, Sapporo Medical University, West 17, South 1, Chuo-ku, Sapporo, Hokkaido, 060-8556, Japan. ktani@sapmed.ac.jp. 4. Department of Rehabilitation, Faculty of Health Sciences, Japan Healthcare University, 11-1-50 Tsukisamuhigashi 3, Toyohira-ku, Sapporo, Hokkaido, 062-0053, Japan. 5. Department of Orthopaedic Surgery, Hitsujigaoka Hospital, 3-1-10 Aoba-cho, Atsubetsu-ku, Sapporo, Hokkaido, 004-0021, Japan.
Abstract
PURPOSE: This study aimed to investigate the time-course changes in the active stiffness of the supraspinatus muscle after arthroscopic rotator cuff repair. METHODS: Eight male patients (mean age 61.5 ± 9.4 years) who underwent arthroscopic rotator cuff repair for small to medium tears were recruited for this study. Movement tasks included 30° shoulder isometric abduction and maximal voluntary isometric contraction of shoulder abduction in the scapular plane. The stiffness of the supraspinatus (anterior superficial, anterior deep, posterior superficial, and posterior deep regions), upper trapezius, and middle deltoid muscles in bilateral shoulders was recorded using ultrasound shear wave elastography. For each subject, the measurement was performed preoperatively and 3, 6, and 12 months postoperatively. RESULTS: The stiffness of the affected anterior superficial region of the supraspinatus muscle 12 months postoperatively was significantly higher than that measured preoperatively and 3 months postoperatively (p < 0.05); it was significantly higher at 6 months postoperatively than at 3 months postoperatively (p < 0.05). Further, the maximal voluntary isometric contraction had significantly improved 12 months postoperatively compared to that measured preoperatively and 3 months postoperatively (p < 0.05). The stiffness of the affected upper trapezius and middle deltoid muscles 12 months postoperatively was significantly lower than that preoperatively (p < 0.05). CONCLUSION: The maximal voluntary isometric contraction 12 months postoperatively possibly increased because of improvement in the active stiffness of the anterior superficial region. Active stiffness of the anterior superficial region may improve 6 months rather than 3 months postoperatively because of the different stages of muscle force, structural repair tendon strength, and remodeling.
PURPOSE: This study aimed to investigate the time-course changes in the active stiffness of the supraspinatus muscle after arthroscopic rotator cuff repair. METHODS: Eight male patients (mean age 61.5 ± 9.4 years) who underwent arthroscopic rotator cuff repair for small to medium tears were recruited for this study. Movement tasks included 30° shoulder isometric abduction and maximal voluntary isometric contraction of shoulder abduction in the scapular plane. The stiffness of the supraspinatus (anterior superficial, anterior deep, posterior superficial, and posterior deep regions), upper trapezius, and middle deltoid muscles in bilateral shoulders was recorded using ultrasound shear wave elastography. For each subject, the measurement was performed preoperatively and 3, 6, and 12 months postoperatively. RESULTS: The stiffness of the affected anterior superficial region of the supraspinatus muscle 12 months postoperatively was significantly higher than that measured preoperatively and 3 months postoperatively (p < 0.05); it was significantly higher at 6 months postoperatively than at 3 months postoperatively (p < 0.05). Further, the maximal voluntary isometric contraction had significantly improved 12 months postoperatively compared to that measured preoperatively and 3 months postoperatively (p < 0.05). The stiffness of the affected upper trapezius and middle deltoid muscles 12 months postoperatively was significantly lower than that preoperatively (p < 0.05). CONCLUSION: The maximal voluntary isometric contraction 12 months postoperatively possibly increased because of improvement in the active stiffness of the anterior superficial region. Active stiffness of the anterior superficial region may improve 6 months rather than 3 months postoperatively because of the different stages of muscle force, structural repair tendon strength, and remodeling.
Authors: Timothy G Baumer; Jack Dischler; Leah Davis; Yassin Labyed; Daniel S Siegal; Marnix van Holsbeeck; Vasilios Moutzouros; Michael J Bey Journal: J Orthop Res Date: 2017-07-31 Impact factor: 3.494