title: Efficacy of rehabilitation (lengthening) exercises, platelet-rich plasma injections, and other conservative interventions in acute hamstring injuries: an updated systematic review and meta-analysis.
abstract: BACKGROUND
  Our 2012 review on therapeutic interventions for acute hamstring injuries found a lack of high-quality studies. The publication of new studies warranted an update.
  
  
  OBJECTIVE
  To update and reanalyse the efficacy of conservative treatments for hamstring injury.
  
  
  METHODS
  PubMed, EMBASE, Web of Science, Cochrane library, CINAHL and SPORTDiscus were searched till mid-February 2015.
  
  
  METHODS
  Randomised controlled trials (RCTs) on the effect of conservative interventions versus a control group or other intervention for hamstring injuries (HI) were included.
  
  
  METHODS
  The search results were screened independently by two authors. Risk of bias assessment was performed using a modified Downs and Black scale with a maximum score of 28. Meta-analysis was performed, where possible.
  
  
  RESULTS
  10 RCTs (526 participants), including 6 new RCTs, were identified. Two RCTs were of good/excellent quality, the rest were fair or poor (median Downs and Black score 16 (IQR 9)). Meta-analysis of two studies on rehabilitation (lengthening) exercises showed a significantly reduced time to return to play (HR 3.22 (95% CI 2.17 to 4.77), p<0.0001) but no difference in risk of re-injury. Meta-analysis of three studies investigating platelet-rich plasma (PRP) showed no effect when compared to control (HR 1.03 (95% CI 0.87 to 1.22), p=0.73). Limited evidence was found that progressive agility and trunk stability training may reduce re-injury rates.
  
  
  CONCLUSIONS
  Meta-analysis showed superior efficacy for rehabilitation exercises. PRP injection had no effect on acute hamstring injury. Limited evidence was found that agility and trunk stabilisation may reduce re-injury rates. The limitations identified in the majority of RCTs should improve the design of new hamstring RCTs.
authors.affiliation: The Sports Physician Group, Department of Sports Medicine, St Lucas Andreas Hospital, Amsterdam, The Netherlands Department of Cardiology, Alrijne Hospital Leiden, Leiden, The Netherlands.
authors.forename: Haiko I M F L
authors.initials: HI
authors.lastname: Pas
authors.affiliation: The Sports Physician Group, Department of Sports Medicine, St Lucas Andreas Hospital, Amsterdam, The Netherlands Department of Orthopaedics, Erasmus Medical Centre, Rotterdam, The Netherlands Department of Orthopaedic Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Reurink
authors.affiliation: The Sports Physician Group, Department of Sports Medicine, St Lucas Andreas Hospital, Amsterdam, The Netherlands Aspetar, Orthopedic and Sports Medicine Hospital, Doha, Qatar Amsterdam Center of Evidence Based Sports Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Johannes L
authors.initials: JL
authors.lastname: Tol
authors.affiliation: Department of Orthopaedic Surgery, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: Adam
authors.initials: A
authors.lastname: Weir
authors.affiliation: Department of Rehabilitation, Nursing Science & Sports, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Marinus
authors.initials: M
authors.lastname: Winters
authors.affiliation: The Sports Physician Group, Department of Sports Medicine, St Lucas Andreas Hospital, Amsterdam, The Netherlands Bergman Clinics, Naarden, The Netherlands.
authors.forename: Maarten H
authors.initials: MH
authors.lastname: Moen
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000534:rehabilitation*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D052580:Muscle Stretching Exercises / Q000379:methods; D018482:Muscle, Skeletal / Q000293:injuries*; D053657:Platelet-Rich Plasma; D016032:Randomized Controlled Trials as Topic; D000068958:Return to Sport; D055815:Young Adult
keywords: Hamstring; Injuries; Physiotherapy; Platelet-Rich Plasma; Review