title: Platelet-Rich Plasma in Addition to Rehabilitation for Acute Hamstring Injuries in NFL Players: Clinical Effects and Time to Return to Play.
abstract: BACKGROUND
  Platelet-rich plasma (PRP) injections have been proposed to hasten soft tissue healing. There is a lack of evidence in the current literature to support their efficacy in elite athletes.
  
  
  OBJECTIVE
  To investigate the effects of the addition of PRP to rehabilitation in the treatment of acute hamstring injuries in professional National Football League (NFL) players and to report the time to return to play.
  
  
  METHODS
  Case control study.
  
  
  METHODS
  Ten NFL players with similar hamstring injury patterns were retrospectively divided into 2 groups. The treatment group (PRP; n = 5) was injected with PRP and the control group (non-PRP; n = 5) was not injected; both groups completed a rehabilitation program. The PRP injections were administered under ultrasound guidance with precise localization of the injury site, within 24 to 48 hours of injury. Age, muscle involved, extent of injury, grading, and time to return to play were noted. Descriptive statistics and the exact Wilcoxon rank-sum test were used for data analysis.
  
  
  RESULTS
  The mean age was 23 years (range, 22-27 years) for the PRP group and 26 years (range, 22-28 years) for the non-PRP group (P = .42). The median longitudinal extent of the injury was 14 cm (range, 9-18 cm) in the PRP group and 15 cm (range, 9-16 cm) in the non-PRP group (P = .77). The average transverse extent of the injury in the PRP and non-PRP groups was 4 cm (range, 1.6-6 cm) and 3.5 cm (range, 2-5 cm), respectively, and the respective average anteroposterior extent was 4 cm (range, 1.9-5 cm) and 2.9 cm (range, 1.5-4 cm). The long head of biceps femoris was most commonly involved (4 in each group), with a single tear of the semimembranosus in each group. The median injury classification was grade 2 in both groups. The median time to return to play was 20 days (range,16-30 days) in the PRP group and 17 days (range, 8-81 days) in the non-PRP group (P = .73).
  
  
  CONCLUSIONS
  There were no significant differences in recovery from hamstring injury between treatment with PRP and routine rehabilitation. A larger, randomized controlled trial is warranted.
authors.affiliation: Methodist Sports Medicine, Indianapolis, Indiana, USA.
authors.forename: Arthur C
authors.initials: AC
authors.lastname: Rettig
authors.affiliation: Center for Diagnostic Imaging, Indianapolis, Indiana, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Meyer
authors.affiliation: Rockland Orthopedics and Sports Medicine, Airmont, New York, USA.
authors.forename: Arup K
authors.initials: AK
authors.lastname: Bhadra
keywords: hamstring injury; platelet-rich plasma; professional football; return to play