title: Theme issue shoulder instability.
authors.affiliation: Arthroscopic and Reconstructive Shoulder Sugery, Aleris Hamlet Parken, Øster Allé 42, 2nd flooor, 2100, Copenhagen Ø, Denmark. skulderbak@gmail.com.
authors.forename: Klaus
authors.initials: K
authors.lastname: Bak
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Direttore U.O. Ortopedia 2, IRCCS Policlinico San Donato, Milan, Italy. pietro.randelli@unimi.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Randelli
authors.affiliation: Department of Orthopaedic Surgery, Saarland University, Kirrberger Str., Geb. 37/38, 66421, Homburg, Saar, Germany. olaf.lorbach@gmx.de.
authors.forename: Olaf
authors.initials: O
authors.lastname: Lorbach