Ersel Gulec, MD, Hayri Ozbek, MD, Sinan Pektas, MD, and Geylan Isik, MD
Pain Physician 2017; 20:197-206 • ISSN 1533-3159
Background: Chronic knee pain is a major widespread problem causing significant impairment
of daily function. Pulsed radiofrequency has been shown to reduce severe chronic joint pain as a
non-pharmacological and less invasive treatment method.
Objective: We aimed to compare the effectiveness of unipolar and bipolar intraarticular pulsed
radiofrequency methods in chronic knee pain control.
Study Design: Prospective, randomized, double-blind study.
Setting: Pain clinic in Cukurova University Faculty of Medicine.
Methods: One hundred patients, aged 20 – 70 years with grade 2 or 3 knee osteoarthritis
were included in this study. Patients were randomly allocated into 2 groups to receive either
unipolar (group U, n = 50) or bipolar (group B, n = 50) intraarticular pulsed radiofrequency (IAPRF)
with a 45 V voltage, 2 Hz frequency, 42° C temperature, 10 msec pulse width, and 10 minute
duration. We recorded visual analog scale (VAS) and Western Ontario and McMaster Universities
Osteoarthritis Index LK 3.1WOMAC (Western Ontario and McMaster Universities Osteoarthritis
Index LK 3.1) scores of patients at baseline and one, 4, and 12 weeks after the procedure. The
primary outcome was the percentage of patients with ≥ 50% reduction in knee pain at 12 weeks
after the procedure.
Results: There was a significant difference between the groups according to VAS scores at all
post-intervention time points. In group B, 84% of patients, and in the group U, 50% of patients
achieved at least 50% knee pain relief from the baseline to 3 months. In group B, WOMAC scores
were significantly lower than the group U at one and 3 months.
Limitations: Lack of long-term clinical results and supportive laboratory tests.
Conclusion: Bipolar IAPRF is more advantageous in reducing chronic knee pain and functional
recovery compared with unipolar IAPRF. Further studies with longer follow-up times, laboratorybased
tests, and different generator settings are required to establish the clinical importance and
well-defined mechanism of action of PRF.
This study protocol was registered at clinicaltrials.gov (identifier: NCT02141529), on May 15,
2014. Institutional Review Board (IRB) approval date: January 16, 2014, and number: 26/9
Key words: Chronic pain, intraarticular, knee joint, knee osteoarthritis, pain management,
pulsed radiofrequency treatment, quality of life, recovery of function
Pain Physician 2017; 20:197-206