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

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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