American Society of Hirudotherapy

Leech Therapy for Thumb Osteoarthritis — RCT

RCT demonstrating efficacy of leech therapy for carpometacarpal joint OA

Last Updated: March 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Clinical TrialsMichalsen A et al. · Pain, 2008

Abstract

Leech therapy has been shown to be effective for symptomatic treatment of osteoarthritis of the knee. We aimed to investigate the effectiveness of leech therapy in another type of osteoarthritis, osteoarthritis of the first carpometacarpal joint (thumb saddle joint). Thirty-two women with symptomatic painful osteoarthritis of the first carpometacarpal joint and who scored>40 mm on a 100mm VAS pain scale were randomized to a single treatment with 2-3 locally applied leeches (leech group) or a 30-day course with topical diclofenac twice a day. Primary outcome measure was change of overall pain (mean of VAS for pain at rest, in motion, during grip) from baseline to day 7. Secondary outcomes were functional disability (DASH-questionnaire), quality of life (QoL, SF-36) and grip strength. Patients were examined baseline and at days 7, 30 and 60 after treatment. Overall pain score at day 7 was reduced from 59.6+/-13.8 to 27.1+/-20.6 in the leech group (n=16) and from 50.6+/-13.3 to 46.9+/-18.5 with diclofenac (n=16) (group difference -26.5, 95%CI -40.3; -12.7; p=0.0003). Group differences for pain relief favoring the leech treatment increased at days 30 and 60. Significant treatment effects were also observed for the DASH score, QoL and grip. Results were not affected by outcome expectation or consumption of analgetics. A single course of leech therapy is effective in relieving pain, improving disability and QoL for at least 2 months. The potential of leech therapy for treatment of arthritic pain and underlying mechanisms should be further investigated.

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

Publication typeComparative StudyJournal ArticleRandomized Controlled TrialResearch Support, Non-U.S. Gov't
Indexed MeSH termsAgedAnimalsAnti-Inflammatory Agents, Non-SteroidalCarpometacarpal JointsDiclofenacFemaleHumansLeechesLeechingMiddle AgedOsteoarthritisPain Measurement

Summary

Randomized controlled trial of leech therapy versus topical diclofenac for symptomatic osteoarthritis of the thumb (first carpometacarpal joint). Demonstrated significant pain reduction and improved hand function, extending the evidence base for hirudotherapy beyond the knee to small-joint OA.

Why This Matters for Hirudotherapy

Expands the evidence base for leech therapy OA efficacy to a different joint, suggesting the mechanism is not site-specific. Important for clinical protocols targeting hand/wrist OA, a common and often poorly managed condition in older adults.

Citation

Leech Therapy for Symptomatic Treatment of First Carpometacarpal Joint Osteoarthritis: Results and Implications of a Pilot Study

Michalsen A et al. · Pain, 2008

Added to ASH library: March 18, 2026 · Site last updated: March 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.

Leech Therapy for Thumb Osteoarthritis — RCT | ASH