title: Analysing the outcome of surgery for chronic Achilles tendinopathy over the last 50 years.
abstract: OBJECTIVE
  To determine an association between when the study was performed, the robustness of the study and the outcomes for insertional and non-insertional Achilles tendinopathy surgery.
  
  
  METHODS
  We performed a systematic review in accordance with the PRISMA guidelines to assess the methodology of studies investigating the outcome of surgery in chronic Achilles tendinopathy over the last 50 years to identify any trends that would account for the variable results. The Coleman Methodology Scores were correlated with the reported percentage success rates and with the publication year to determine any trends using Pearson's correlation.
  
  
  RESULTS
  We identified 62 studies published between 1964 and 2014 reporting on a total of 2923 surgically treated Achilles tendinopathies. The average follow-up time was 40 mo (range 5-204 mo), and the mean reported success rate was 83.5% (range 36%-100%). The Coleman Methodology Scores were highly reproducible (r = 0.99, P < 0.01), with a mean of 40.1 (SD 18.9, range 2-79). We found a negative correlation between reported success rate and overall methodology scores (r = -0.40, P < 0.001), and a positive correlation between year of publication and overall methodology scores (r = 0.46, P < 0.001).
  
  
  CONCLUSIONS
  We conclude that although the success rate of surgery for chronic Acilles tendinopathy described in the literature has fallen over the last 50 years, this is probably due to a more rigorous methodology of the studies.
authors.affiliation: Wasim S Khan, Seema Malvankar, Jagmeet S Bhamra, Ioannis Pengas, University College London Institute of Orthopaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, Stanmore, Middlesex, London HA7 4LP, United Kingdom.
authors.forename: Wasim S
authors.initials: WS
authors.lastname: Khan
authors.affiliation: Wasim S Khan, Seema Malvankar, Jagmeet S Bhamra, Ioannis Pengas, University College London Institute of Orthopaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, Stanmore, Middlesex, London HA7 4LP, United Kingdom.
authors.forename: Seema
authors.initials: S
authors.lastname: Malvankar
authors.affiliation: Wasim S Khan, Seema Malvankar, Jagmeet S Bhamra, Ioannis Pengas, University College London Institute of Orthopaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, Stanmore, Middlesex, London HA7 4LP, United Kingdom.
authors.forename: Jagmeet S
authors.initials: JS
authors.lastname: Bhamra
authors.affiliation: Wasim S Khan, Seema Malvankar, Jagmeet S Bhamra, Ioannis Pengas, University College London Institute of Orthopaedics and Musculoskeletal Science, Royal National Orthopaedic Hospital, Stanmore, Middlesex, London HA7 4LP, United Kingdom.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Pengas
keywords: Achilles tendon; Methodology; Outcome; Surgery; Tendinopathy