Tim Kraal, Inger Sierevelt, Lijkele Beimers, Department of Orthopedic Surgery, Slotervaart Center of Orthopedic Research and Education, Amsterdam 1066 EC, The Netherlands
Derek van Deurzen, Michel PJ van den Bekerom, Department of Orthopedic Surgery, Shoulder and Elbow Unit, OLVG Hospital, Amsterdam 1091 AC, The Netherlands
Author contributions: Kraal T is the initiator of this study and wrote the study protocol and a large part of this manuscript; Sierevelt I is involved as a clinical epidemiologist and research coordinator; Sierevelt I is responsible for the statistical analysis and correct presentation of the results; van Deurzen D and van den Bekerom MPJ both included patients at their center, and were both responsible for follow up at this location; Beimers L is responsible for inclusions at the other center and responsible as supervisor for the protocol and progress of the study; all authors were involved in the writing and revising of this manuscript.
Institutional review board statement: Approval for a prospective randomized clinical trial (D-FROST; Dutch frozen shoulder study) was obtained by the MC Slotervaart Hospital Medical Ethics Committee (NL47325.048.13).
Clinical trial registration statement: The trial was registered in the Dutch Trial Register (NTR4587).
Conflict-of-interest statement: All authors declare that they have no conflict of interest to declare.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised according to the CONSORT 2010 Statement.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Lijkele Beimers, MD, PhD, Staff Physician, Orthopedic Surgeon, Department of Orthopedic Surgery, Slotervaart Center of Orthopedic Research and Education, MC Slotervaart, Louwesweg 6, Amsterdam 1066 EC, The Netherlands. email@example.com
Received: April 7, 2018
Peer-review started: April 7, 2018
First decision: June 14, 2018
Revised: July 1, 2018
Accepted: August 2, 2018
Article in press: August 3, 2018
Published online: September 18, 2018