American Society of Hirudotherapy

Effectiveness of medicinal leech therapy in moderate knee osteoarthritis: a pilot study

Zaidi SM, Jameel SS, Zaman F, Jilani S, Sultana A, Khan SA (2009) · Hindawi Journal of Evidence-Based Complementary & Alternative Medicine · n=30

RCT evidence detailTrial reference
GRADE Very LowInsufficient evidenceCondition: Knee Osteoarthritis
Sample size of this trial compared with other Knee Osteoarthritis trialsWang H 2018264Lauche R 2025240Lauche R 2014237Farzali S 2025181Cui Y 2024144Andereya S 2008113Andereya S 2008113Sarbaev IS 201996Isik M 201790Zaidi SM 200930
This trial (highlighted) by sample size alongside other indexed Knee Osteoarthritis trials. Larger trials generally carry more statistical weight.

Study Profile

Design
single-center, open-label, randomized pilot trial (Karachi)
Sample size (n)
30
Intervention
Two sessions of 2-4 Hirudinaria granulosa leeches at the symptomatic knee, 14 days apart
Comparator
Diclofenac sodium 50mg twice daily for 4 weeks
Primary endpoint
WOMAC composite at week 4
Primary result
WOMAC composite improvement 56% in leech vs 39% in diclofenac at week 4 (p=0.04)
Effect size (Cohen's d)
0.65
Follow-up duration
8 weeks

Key Findings

  • First Unani medicine RCT context for hirudotherapy
  • Used H. granulosa (Indian/South Asian species)
  • Effect emerged at week 2, peaked at week 4
  • Comparator oral NSAID (diclofenac) more stringent than topical preparations
  • Patient adherence to leech 100% — to NSAID 87%

Limitations

  • Small sample (n=30)
  • Open-label
  • Single center, Unani medicine context
  • Short follow-up (8 weeks)
  • WOMAC not formally validated in Urdu

Clinical Implications

Zaidi 2009 is the first RCT-level evidence from a Unani medicine context. As with Karandikar 2018 (Ayurveda), the use of H. granulosa rather than H. medicinalis limits direct US clinical applicability. The trial primarily supports the species-agnostic effect hypothesis. For US clinicians, this trial is best treated as supporting evidence rather than primary citation.

Related Trials

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.