title: Progression of patellar tendinitis following treatment with platelet-rich plasma: case reports.
abstract: OBJECTIVE
  The use of platelet-rich plasma (PRP) is becoming more attractive given its favourable side effect profile and autologous nature, leading to rapid clinical adoption in the absence of high-level evidence. We are presenting three patients who developed a progression of patellar tendinitis following treatment, which to our knowledge is the first report of worsening of patellar tendinitis following PRP therapy.
  
  
  METHODS
  The records of three patients with symptom exacerbation of patellar tendinitis following treatment with PRP were reviewed. IRB exemption was obtained. Clinical and operative records, radiographs, and MR imaging were reviewed for all patients.
  
  
  RESULTS
  Three patients reported to our clinic for a second opinion with symptoms of anterior knee pain consistent with patellar tendinitis. Each patient had previously been treated with PRP therapy due to prolonged symptoms. Clinical and radiological findings following treatment included patellar tendon thickening, worsening pain, discontinuation of athletic participation in all three patients, and osteolysis of the distal pole of the patella in one patient identified during surgical intervention.
  
  
  CONCLUSIONS
  Growing interest in the use of autologous products for the management of chronic tendinopathies has led to widespread clinical implementation with minimal scientific support. It is tempting to apply a new treatment for management of a difficult clinical entity, especially when the risk/benefit ratio appears favourable. However, caution must be exercised as unexpected results may be encountered.
  
  
  METHODS
  Case reports, level V.
authors.affiliation: Harbour Sports Medicine, Wardell Orthopaedics, 5818D Harbourview Drive, Suite 150, Suffolk, VA 23435, USA. karlbowm@gmail.com
authors.forename: Karl F
authors.initials: KF
authors.lastname: Bowman
authors.forename: Bart
authors.initials: B
authors.lastname: Muller
authors.forename: Kellie
authors.initials: K
authors.lastname: Middleton
authors.forename: Christian
authors.initials: C
authors.lastname: Fink
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Harner
authors.forename: Freddie H
authors.initials: FH
authors.lastname: Fu
mesh_terms: D000293:Adolescent; D000328:Adult; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017847:Patellar Ligament / Q000000981:diagnostic imaging / Q000473:pathology; D053657:Platelet-Rich Plasma; D052256:Tendinopathy / Q000628:therapy*; D014463:Ultrasonography