Factors Associated with the Good Outcome after a Single Injection of Platelet-Rich Plasma in Patients with Osteoarthritic Knee: A Prospective Cohort Study


  • Natnaree Tikkapanyo Department of Rehabilitation Medicine, Phramongkutklao Hospital and Phramongkutklao College of Medicine, Bangkok, Thailand
  • Narathorn Soponprapakorn Department of Rehabilitation Medicine, Phramongkutklao Hospital and Phramongkutklao College of Medicine, Bangkok, Thailand
  • Chanwit Phongamwong Department of Rehabilitation Medicine, Phramongkutklao Hospital and Phramongkutklao College of Medicine, Bangkok, Thailand


knee osteoarthritis, platelet-rich plasma, intra-articular injection, cohort study


Objectives: To determine the associated factors with the good outcome of a single dose intraarticular platelet-rich plasma (IA PRP) injection on pain reduction in patients with knee osteoarthritis.

Study design: A prospective cohort study.

Setting: Outpatient Department of Rehabilitation Medicine at Phramongkutklao Hospital.

Subjects: Patients with mild to severe knee osteoarthritis

Methods: Patients with knee osteoarthritis who received a single IA PRP injection were eligible to participate in this study. The visual analog scale (VAS) score as a primary outcome and the dimension of physical function as measured by the SF-36 questionnaire were determined at baseline and at week four after the injection. A good outcome was defined as a ≥30% reduction from baseline VAS at week four. Logistic regression was performed to determine factors associated with good outcomes of a single injection of IA PRP.

Results: Fifty-eight patients with knee osteoarthritis participated in this study. The mean difference in VAS scores between baseline and week 4 was -1.58 (2.11) with a p < 0.001. However, only 41.34% of the participants had a good outcome. Multivariable analysis found no significant factors associated with good outcomes.

Conclusions: Less than half the participants had clinically significant improvement in VAS four weeks after a single injection of IA PRP. However, the present study did not have sufficient statistical power to determine associated factors for a good outcome, possibly due to the small sample size.


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