Juan C Villa-Camacho1, Stephen Okajima1, Miguel E Perez-Viloria1, Kempland C Walley2, David Zurakowski3, Edward K Rodriguez4, Ara Nazarian5. 1. Center for Advanced Orthopaedic Studies, Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center-Harvard Medical School, Boston, MA, USA. 2. Center for Advanced Orthopaedic Studies, Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center-Harvard Medical School, Boston, MA, USA; Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center-Harvard Medical School, Boston, MA, USA. 3. Department of Anesthesiology, Boston Children's Hospital-Harvard Medical School, Boston, MA, USA. 4. Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center-Harvard Medical School, Boston, MA, USA. 5. Center for Advanced Orthopaedic Studies, Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center-Harvard Medical School, Boston, MA, USA. Electronic address: anazaria@bidmc.harvard.edu.
Abstract
BACKGROUND AND HYPOTHESIS: We hypothesized that extra-articular, internal fixation of the shoulder in rats would result in a subsequent decrease in rotational range of motion (ROM) and an increase in joint stiffness. We further hypothesized that residual kinematic changes would still be present at 8 weeks after immobilization. Extra-articular, internal fixation of the shoulder has been used to induce adhesive capsulitis in rats; however, the effects on in vivo kinematics have not been assessed. METHODS: Baseline measurements of rotational torque and ROM were acquired (n = 10 rats), and the left forelimb of each animal was immobilized with sutures passed between the scapula and the humeral shaft. After 8 weeks, the sutures were removed, and changes in kinematics and kinetics were longitudinally quantified in the follow-up period. Changes in stiffness, defined as the area under the angle-torque curve, were also quantified. RESULTS: Immediately after suture removal, there was a 63% decrease in total ROM compared with baseline (51° ± 10° vs. 136° ± 0°; P < .001). Similarly, total torque was found to increase 13.4 N.mm compared with baseline (22.6 ± 5.9 N.mm vs. 9.2 ± 2.6 N.mm; P = .002). Residual total ROM restrictions and an increased torque in internal rotation were still evident at 8 weeks of follow-up (113° ± 8° vs. 137° ± 0°, P < .001 and 3.5 ± 0.4 N.mm vs. 2.7 ± 0.7 N.mm, P = .036). Stiffness also increased after suture removal and at 8 weeks of follow-up compared with baseline. CONCLUSION: This animal model of adhesive capsulitis rendered lasting effects on in vivo kinematics of the shoulder.
BACKGROUND AND HYPOTHESIS: We hypothesized that extra-articular, internal fixation of the shoulder in rats would result in a subsequent decrease in rotational range of motion (ROM) and an increase in joint stiffness. We further hypothesized that residual kinematic changes would still be present at 8 weeks after immobilization. Extra-articular, internal fixation of the shoulder has been used to induce adhesive capsulitis in rats; however, the effects on in vivo kinematics have not been assessed. METHODS: Baseline measurements of rotational torque and ROM were acquired (n = 10 rats), and the left forelimb of each animal was immobilized with sutures passed between the scapula and the humeral shaft. After 8 weeks, the sutures were removed, and changes in kinematics and kinetics were longitudinally quantified in the follow-up period. Changes in stiffness, defined as the area under the angle-torque curve, were also quantified. RESULTS: Immediately after suture removal, there was a 63% decrease in total ROM compared with baseline (51° ± 10° vs. 136° ± 0°; P < .001). Similarly, total torque was found to increase 13.4 N.mm compared with baseline (22.6 ± 5.9 N.mm vs. 9.2 ± 2.6 N.mm; P = .002). Residual total ROM restrictions and an increased torque in internal rotation were still evident at 8 weeks of follow-up (113° ± 8° vs. 137° ± 0°, P < .001 and 3.5 ± 0.4 N.mm vs. 2.7 ± 0.7 N.mm, P = .036). Stiffness also increased after suture removal and at 8 weeks of follow-up compared with baseline. CONCLUSION: This animal model of adhesive capsulitis rendered lasting effects on in vivo kinematics of the shoulder.
Authors: William A Blessing; Stephen M Okajima; M Belen Cubria; Juan C Villa-Camacho; Miguel Perez-Viloria; Patrick M Williamson; Angie N Sabogal; Sebastian Suarez; Lay-Hong Ang; Suzanne White; Evelyn Flynn; Edward K Rodriguez; Mark W Grinstaff; Ara Nazarian Journal: Proc Natl Acad Sci U S A Date: 2019-06-03 Impact factor: 11.205
Authors: Stephen M Okajima; M Belen Cubria; Sharri J Mortensen; Juan C Villa-Camacho; Philip Hanna; Aron Lechtig; Miguel Perez-Viloria; Patrick Williamson; Mark W Grinstaff; Edward K Rodriguez; Ara Nazarian Journal: J Vis Exp Date: 2018-09-28 Impact factor: 1.355
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