title: Revision anterior cruciate ligament reconstruction: clinical outcome and evidence for return to sport.
abstract: OBJECTIVE
  An increasing number of patients undergo revision anterior cruciate ligament (ACL) reconstruction, with the intention of returning to sport being a major indication. The aim of this study is to assess the available evidence for clinical improvement and return to sport, to understand the real potential of this procedure in regaining functional activity, and to facilitate improved counselling of patients regarding the expected outcome after revision ACL reconstruction.
  
  
  METHODS
  The search was conducted on the PubMed database. Articles reporting clinical results for revision ACL reconstruction were included. A meta-analysis was performed on return to sport, and results were compared to the literature on primary ACL reconstruction. Other specific clinical outcomes (Lysholm, Tegner, IKDC Objective scores) were also included in the meta-analysis.
  
  
  RESULTS
  Of the 503 identified records, a total of 59 studies involving 5365 patients were included in the qualitative data synthesis. Only 31 articles reported the rate of return to sport. Whereas 73 % of good objective results and satisfactory subjective results were documented, 57 % of patients did not return to the same level of sport activity, significantly inferior to that of a primary procedure.
  
  
  CONCLUSIONS
  The real potential of revision ACL reconstruction should not be overestimated due to the low number of patients able to return to their previous activity level, significantly inferior with respect to that reported for primary ACL reconstruction. This finding will help physicians in the clinical practice providing realistic expectations to the patients. Future studies should focus on participation-based outcome measures such as return to sport and in strategies to improve the results in terms of return to previous activities after revision ACL reconstruction.
  
  
  METHODS
  Systematic review and meta-analysis including Level IV studies, Level IV.
authors.affiliation: II Orthopaedic and Traumatologic Clinic - Biomechanics and Technology Innovation Laboratory, Rizzoli Orthopaedic Institute, Via Di Barbiano, 1/10, 40136, Bologna, Italy. lucas.andriolo@gmail.com.
authors.forename: Luca
authors.initials: L
authors.lastname: Andriolo
authors.affiliation: II Orthopaedic and Traumatologic Clinic - Biomechanics and Technology Innovation Laboratory, Rizzoli Orthopaedic Institute, Via Di Barbiano, 1/10, 40136, Bologna, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Filardo
authors.affiliation: II Orthopaedic and Traumatologic Clinic - Biomechanics and Technology Innovation Laboratory, Rizzoli Orthopaedic Institute, Via Di Barbiano, 1/10, 40136, Bologna, Italy.|Nano-Biotechnology Laboratory, Rizzoli Orthopaedic Institute, Bologna, Italy.
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Kon
authors.affiliation: Isokinetic Medical Group, FIFA Medical Centre of Excellence, Bologna, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Ricci
authors.affiliation: Isokinetic Medical Group, FIFA Medical Centre of Excellence, Bologna, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Della Villa
authors.affiliation: Isokinetic Medical Group, FIFA Medical Centre of Excellence, Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Della Villa
authors.affiliation: II Orthopaedic and Traumatologic Clinic - Biomechanics and Technology Innovation Laboratory, Rizzoli Orthopaedic Institute, Via Di Barbiano, 1/10, 40136, Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Zaffagnini
authors.affiliation: II Orthopaedic and Traumatologic Clinic - Biomechanics and Technology Innovation Laboratory, Rizzoli Orthopaedic Institute, Via Di Barbiano, 1/10, 40136, Bologna, Italy.
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D006801:Humans; D012086:Reoperation; D000068958:Return to Sport
keywords: Clinical outcome; Meta-analysis; Return to sport; Revision ACL