title: Clinical findings just after return to play predict hamstring re-injury, but baseline MRI findings do not.
abstract: BACKGROUND
  Acute hamstring re-injuries are common and hard to predict. The aim of this study was to investigate the association between clinical and imaging findings and the occurrence of hamstring re-injuries.
  
  
  METHODS
  We obtained baseline data (clinical and MRI findings) of athletes who sustained an acute hamstring injury within 5 days of initial injury. We also collected data of standardised clinical tests within 7 days after return to play (RTP). The number of re-injuries was recorded within 12 months. We analysed the association between the possible predictive variables and re-injuries with a multivariate Cox proportional-hazards regression model.
  
  
  RESULTS
  Eighty patients were included at baseline and 64 patients could be included in the final analysis because data after RTP were not available in 16 cases. There were 17 re-injuries (27%). None of the baseline MRI findings were univariately associated with re-injury. A higher number of previous hamstring injuries (adjusted OR (AOR) 1.33; 95% CI 1.11 to 1.61), more degrees of active knee extension deficit after RTP (AOR 1.13; 95% CI 1.03 to 1.25), isometric knee flexion force deficit at 15° after RTP (AOR 1.04; 95% CI 1.01 to 1.07) and presence of localised discomfort on hamstring palpation after RTP (AOR 3.95; 95% CI 1.38 to 11.37) were significant independent predictors of re-injury. Athletes with localised discomfort on hamstring palpation just after RTP were consequently almost four times more likely to sustain a re-injury.
  
  
  CONCLUSIONS
  The number of previous hamstring injuries, active knee extension deficit, isometric knee flexion force deficit at 15° and presence of localised discomfort on palpation just after RTP are associated with a higher hamstring re-injury rate. None of the baseline MRI parameters was a predictor of hamstring re-injury.
  
  
  BACKGROUND
  ClinicalTrial.gov number NCT01812564.
authors.affiliation: Department of Sports Medicine, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar Department of Orthopaedics, Erasmus Medical Centre, Rotterdam, The Netherlands Department of Sports Medicine, The Hague Medical Center, Leidschendam, The Netherlands.
authors.forename: Robert-Jan
authors.initials: RJ
authors.lastname: De Vos
authors.affiliation: Department of Orthopaedics, Erasmus Medical Centre, Rotterdam, The Netherlands.
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Reurink
authors.affiliation: Department of Sports Medicine, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Goudswaard
authors.affiliation: Department of Sports Medicine, Bergman Clinics, Naarden, The Netherlands The Sportsphysician Group, St. Lucas Andreas Hospital, Amsterdam, The Netherlands.
authors.forename: Maarten H
authors.initials: MH
authors.lastname: Moen
authors.affiliation: Department of Sports Medicine, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
authors.forename: Adam
authors.initials: A
authors.lastname: Weir
authors.affiliation: Department of Sports Medicine, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
authors.forename: Johannes L
authors.initials: JL
authors.lastname: Tol
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000503:physiopathology / Q000534:rehabilitation*; D004311:Double-Blind Method; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011379:Prognosis; D020127:Recovery of Function; D012008:Recurrence; D013708:Tendon Injuries / Q000534:rehabilitation*; D013997:Time Factors; D055815:Young Adult
keywords: Hamstring; MRI; Muscle Damage/Injuries; Sports Physiotherapy; Sports Rehabilitation Programs