title: Platelet-rich plasma for the treatment of patellar tendinopathy: clinical and imaging findings at medium-term follow-up.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy of multiple platelet-rich plasma (PRP) injections on the healing of chronic refractory patellar tendinopathy, and report the quality and duration of the clinical improvement up to a medium-term follow-up.
  
  
  METHODS
  Forty-three patients (mean age, 30.6 years; mean BMI, 24.7; 42 men, one woman) affected by chronic patellar proximal tendinopathy were enrolled in this trial. Eleven patients were affected by bilateral tendinopathy. They underwent three ultrasound guided intra-tendinous injections of five millilitres PRP, two weeks apart from each other. Patients were prospectively evaluated initially, then after two, six, and up to mean 48.6 ± 8.1 months of follow-up (minimum evaluation at 36 months). The following evaluation tools were used: Blanzina, VISA-P, EQ-VAS for general health, and Tegner scores. Patients' overall satisfaction and time to return to sport were also reported.
  
  
  RESULTS
  Good and stable results were documented over time, with the VISA-P score increasing from 44.1 ± 15.6 at baseline to 61.4 ± 22.2 at two months, 76.6 ± 25.4 at six months, and 84.3 ± 21.6 at four years' follow-up. The same trend was confirmed by the other scores used, and 80 % of the patients were satisfied and returned to previous sports activities. Significantly poorer results were obtained in patients with a longer history of symptoms, and poor results were also observed in bilateral lesions. No correlation between ultrasonographic and clinical findings could be found.
  
  
  CONCLUSIONS
  Multiple injections of PRP provided a good clinical outcome for the treatment of chronic recalcitrant patellar tendinopathy with stable results up to medium-term follow-up. Patients affected by bilateral pathology and presenting a long history of pain obtained significantly poorer results.
authors.affiliation: II Orthopaedic and Traumatology Clinic - Biomechanics and Technology Innovation Laboratory, Rizzoli Orthopaedic Institute, Bologna, Italy. g.filardo@biomec.ior.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Filardo
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Kon
authors.forename: Berardo
authors.initials: B
authors.lastname: Di Matteo
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pelotti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Di Martino
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007267:Injections; D008297:Male; D018919:Neovascularization, Physiologic / Q000502:physiology; D017847:Patellar Ligament / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D017060:Patient Satisfaction; D053657:Platelet-Rich Plasma; D020127:Recovery of Function / Q000502:physiology; D012189:Retrospective Studies; D052256:Tendinopathy / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D014463:Ultrasonography