title: Evidence-based indications for hindfoot endoscopy.
abstract: OBJECTIVE
  The 2-portal hindfoot endoscopic technique with the patient in prone position, first introduced by van Dijk et al. (Arthroscopy 16:871-876, 2000), is currently the most used by foot and ankle surgeons to address endoscopically pathologies located in the hindfoot. This article aims to review the literature to provide a comprehensive description of the level of evidence available to support the use of the 2-portal hindfoot endoscopy technique for the current generally accepted indications.
  
  
  METHODS
  A comprehensive review was performed by use of the PubMed database to isolate literature that described therapeutic studies investigating the results of different hindfoot endoscopy treatment techniques. All articles were reviewed and assigned a classification (I-V) of level of evidence. An analysis of the literature reviewed was used to assign a grade of recommendation for each current generally accepted indication for hindfoot endoscopy. A subscale was used to further describe the evidence base for indications receiving a grade of recommendation indicating poor-quality evidence.
  
  
  RESULTS
  On the basis on the available evidence, posterior ankle impingement syndrome, subtalar arthritis and retrocalcaneal bursitis have the strongest recommendation in favour of treatment (grade Cf).
  
  
  CONCLUSIONS
  Although a low level of evidence of the included studies, the review showed that adequate literature to support the use of the 2-portal endoscopic techniques for most currently accepted indications exists. Future "higher quality" evidence could strengthen current recommendations and further help surgeons in evidence-based practice.
  
  
  METHODS
  Level V, Review of Level III, IV and V studies.
authors.affiliation: IRCCS Policlinico San Donato, Via Morandi 30, 20097, San Donato Milanese, Milan, Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Spennacchio
authors.affiliation: IRCCS Policlinico San Donato, Via Morandi 30, 20097, San Donato Milanese, Milan, Italy. d.cucchi@gmail.com.|Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133, Milan, Italy. d.cucchi@gmail.com.
authors.forename: Davide
authors.identifier: http://orcid.org/0000-0001-6284-7977
authors.initials: D
authors.lastname: Cucchi
authors.affiliation: IRCCS Policlinico San Donato, Via Morandi 30, 20097, San Donato Milanese, Milan, Italy.|Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Via Mangiagalli 31, 20133, Milan, Italy.
authors.forename: Pietro S
authors.initials: PS
authors.lastname: Randelli
authors.affiliation: Department of Orthopaedic Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam Zuid-Oost, The Netherlands.
authors.forename: Niek C
authors.initials: NC
authors.lastname: van Dijk
mesh_terms: D000843:Ankle Joint / Q000601:surgery*; D001182:Arthroscopy; D004724:Endoscopy; D005528:Foot; D006801:Humans
keywords: Ankle; Grade of recommendation; Hindfoot endoscopy; Posterior ankle arthroscopy; Systematic review