title: One injection of platelet-rich plasma associated to a submaximal eccentric protocol to treat chronic jumper's knee.
abstract: OBJECTIVE
  Jumper's knee is a frequent chronic overuse syndrome of the proximal part of the patellar tendon. Platelets contain lots of growth factors which could enhance the healing process of tendons. The aim of this study was to clarify the possible efficacy of one injection of Platelet-rich plasma (PRP) in cases of rebel jumper's knees.
  
  
  METHODS
  Twenty patients with chronic proximal patellar tendinopathy were enrolled. Assessments were made before infiltration of PRP, and 6 weeks and 3 months after the infiltration, using a 10-point visual analogic scale of pain, clinical examinations with a pressure algometer, algofunctional scores (IKDC and VISA-P), functional assessments (isokinetic and optojump evaluations) and imagery (ultrasounds and MRI). The PRP was obtained with an apheresis system (COMTEC®, Fresenius-Kabi, Bad Homburg, Germany). Six millilitres of PRP were injected without local anesthetic. One week after infiltration, patients started a standardized sub-maximal eccentric reeducation.
  
  
  RESULTS
  During daily activities pain significantly decreased with time. At functional evaluation, it decreased as well, but without significant functional improvement. No improvements in the imagery measurements were observed. Younger patients seemed to be more susceptible to have an improvement of pain by the PRP infiltration.
  
  
  CONCLUSIONS
  This study demonstrates that a local infiltration of PRP associated with a submaximal eccentric protocol can improve symptoms of chronic jumper's knee in patients non-responsive to classical conservative treatments.
authors.affiliation: Physical Medicine and Sports Traumatology Department, University and University Hospital of Liège, Liège, Belgium - jfkaux@chu.ulg.ac.be.
authors.forename: J F
authors.initials: JF
authors.lastname: Kaux
authors.forename: J L
authors.initials: JL
authors.lastname: Croisier
authors.forename: O
authors.initials: O
authors.lastname: Bruyere
authors.forename: C
authors.initials: C
authors.lastname: Rodriguez De La Cruz
authors.forename: B
authors.initials: B
authors.lastname: Forthomme
authors.forename: G
authors.initials: G
authors.lastname: Brabant
authors.forename: S
authors.initials: S
authors.lastname: Lapraille
authors.forename: V
authors.initials: V
authors.lastname: Lonneux
authors.forename: D
authors.initials: D
authors.lastname: Noel
authors.forename: C
authors.initials: C
authors.lastname: Le Goff
authors.forename: A
authors.initials: A
authors.lastname: Gothot
authors.forename: J
authors.initials: J
authors.lastname: Collette
authors.forename: J M
authors.initials: JM
authors.lastname: Crielaard
mesh_terms: D000328:Adult; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D053657:Platelet-Rich Plasma; D052256:Tendinopathy / Q000503:physiopathology / Q000628:therapy*; D064232:Visual Analog Scale