Name	Location	Contribution
Matti Ahonen, MD, PhD	Helsinki University Hospital, Finland	Drafting/revision of the manuscript for content, including medical writing for content; study concept or design; and analysis or interpretation of data
Ilkka Helenius, MD, PhD	Department of Orthopaedics and Traumatology, University of Helsinki and Helsinki University Hospital, Finland	Drafting/revision of the manuscript for content, including medical writing for content; study concept or design; and analysis or interpretation of data
Mika Gissler, DPhil	THL Finnish Institute for Health and Welfare, Helsinki, Finland	Drafting/revision of the manuscript for content, including medical writing for content; major role in the acquisition of data; study concept or design; and analysis or interpretation of data
Ira Jeglinsky-Kankainen, PhD	Department of Health and Welfare, Arcada University of Applied Sciences, Helsinki, Finland	Drafting/revision of the manuscript for content, including medical writing for content; study concept or design; and analysis or interpretation of data