American Society of Hirudotherapy

Comparison of the effectiveness of medicinal leech and TENS therapy in the treatment of primary osteoarthritis of the knee: A randomized controlled trial

RCT published in Zeitschrift für Rheumatologie (2017)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Randomized controlled trialClinical TrialsIsik M, Ugur M, Yakisan RS, Sari T, Yilmaz N · Zeitschrift fur Rheumatologie, 2017

Abstract

OBJECTIVES: The aim of this study was to evaluate the effects of leech therapy in the treatment of knee osteoarthritis in terms of duration of effectiveness and symptom relief and to compare these results with transcutaneous electrical nerve stimulation (TENS) therapy. MATERIAL AND METHODS: This study was designed as a prospective, single center, randomized, single-blind and parallel group study. A total of 90 patients were included in the study, 46 in the leech group and 44 in the TENS group. Primary outcome measures were changes of the pain scores in visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) on the measurements day 0, 21 and 180. Secondary outcome measures were the changes in the sub-groups of the WOMAC scores. Five leeches were applied to the affected knee, once every week for 3 weeks. RESULTS: The VAS pain score showed a similar decrease in both groups in the evaluation on day 21 (p < 0.001). The course of the change of the VAS pain score in both groups was similar in the comparisons between groups. Long-term benefits of the TENS therapy group were slightly more than the leech therapy group. All the sub-scores of WOMAC in both therapy groups showed a similar decrease (p = 0.819). Throughout the study this decrease was statistically significant in both groups (p < 0.001). CONCLUSION: Leech therapy relieves symptoms in patients with osteoarthritis of the knee and is as effective as TENS therapy in the management of osteoarthritis of the knee. This treatment has the potential of being an additional or alternative therapy for the non-surgical management of osteoarthritis of the knee.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeComparative StudyJournal ArticleRandomized Controlled Trial
Indexed MeSH termsAdultAgedFemaleHumansLeechingMaleMiddle AgedOsteoarthritis, KneeProspective StudiesSingle-Blind MethodTranscutaneous Electric Nerve StimulationTreatment Outcome

Summary

Randomized comparison of leech therapy (n=46) versus TENS (n=44) for primary knee osteoarthritis demonstrates similar significant VAS pain and WOMAC reductions at days 21 and 180, validating leech therapy as effective alternative.

Why This Matters for Hirudotherapy

RCT-level evidence positioning leech therapy as a competitive non-pharmacological option for knee osteoarthritis.

Citation

Comparison of the effectiveness of medicinal leech and TENS therapy in the treatment of primary osteoarthritis of the knee: A randomized controlled trial.

Isik M, Ugur M, Yakisan RS, Sari T, Yilmaz N · Zeitschrift fur Rheumatologie, 2017

Added to ASH library: May 26, 2026 · Site last updated: June 18, 2026

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.