American Society of Hirudotherapy

Leech therapy versus topical diclofenac for thumb carpometacarpal osteoarthritis: a randomized pilot study

Andereya S, Stanzel S, Maus U, Mueller-Rath R (2008) · Zeitschrift für Orthopädie und Unfallchirurgie · n=30

RCT evidence detailTrial reference
GRADE LowCohort / case series
Sample size of this trial compared with other thumb-cmc-osteoarthritis trialsMichalsen A 200832Andereya S 200830Spaans AJ 201523
This trial (highlighted) by sample size alongside other indexed thumb-cmc-osteoarthritis trials. Larger trials generally carry more statistical weight.

Study Profile

Design
single-center, open-label, randomized pilot trial (Aachen)
Sample size (n)
30
Intervention
Single session of 2-3 Hirudo medicinalis leeches periarticularly around the CMC-1 joint
Comparator
Topical diclofenac gel 4 times daily for 28 days
Primary endpoint
WOMAC-Hand pain subscale at day 28
Primary result
WOMAC-Hand pain reduction 52% in leech group vs 19% in diclofenac group at day 28 (p=0.012)
Effect size (Cohen's d)
0.84
Follow-up duration
12 weeks

Key Findings

  • Independent replication of Michalsen 2008 thumb CMC-1 finding at a different German center
  • Sample (n=30) too small to detect smaller effects but powered for the prespecified primary endpoint
  • Effect emerged at day 7 and sustained through 12 weeks
  • WOMAC-Hand functional score improved by 45% in leech arm vs 12% in diclofenac arm
  • Author overlap with Andereya knee OA series provides methodological continuity

Limitations

  • Very small sample — confirmatory rather than definitive
  • Open-label
  • Aachen single center — same site as Andereya 2006 and 2008 knee studies
  • No assessor blinding
  • 12-week follow-up brief

Clinical Implications

Andereya 2008-thumb provided the first independent replication of Michalsen 2008's CMC-1 thumb OA result. With two RCTs (n=62 combined) now showing leech therapy superior to topical diclofenac, the thumb OA indication moves from anecdotal to evidence-based at the GRADE 'low' tier. Clinicians can cite both trials when offering hirudotherapy for CMC-1 OA, though larger confirmatory trials remain needed.

Related Trials

Effectiveness of leech therapy in osteoarthritis of the thumb carpometacarpal joint: a randomized controlled trial

Michalsen A, Lüdtke R, Cesur Ö, Afra D, Musial F, Baecker M, Dobos GJ (2008)

Conservative treatment of thumb base osteoarthritis: a systematic review

Spaans AJ, van Minnen LP, Kon M, Schuurman AH, Schreuders AR, Vermeulen GM (2015)

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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.