Amerikanische Gesellschaft für Hirudotherapie

Knee Osteoarthritis

Off-label use with three RCTs showing pain and function improvement comparable to NSAID gel at 3 months in mild-to-moderate symptomatic knee OA.

Tier B — RCT-supported off-labelOff-Label untersuchtLast updated: 2026-05-26 · Reviewed by ASH Editorial Board

Patienten-Zusammenfassung

Ist dies FDA-zugelassen fuer diese Anwendung?
No — investigated off-label. The FDA cleared medicinal leeches in 2004 only for venous congestion in microsurgical reconstruction (K040187). Use for knee osteoarthritis is supported by published research but not FDA-evaluated.
Welche Evidenz existiert?
Several published randomized trials (Michalsen 2003, Stange 2012, Andereya 2008, İşık 2017) and a 2014 meta-analysis (Lauche et al.) suggest a moderate, short-to-medium-term reduction in knee pain compared to standard comparators such as topical NSAID gel, TENS, or a sham control. Effects have been measured out to about 3 months. The trials are mostly from research groups in Germany, all are small (under 130 patients), and longer-term outcomes (12+ months) are not well studied. This is not a substitute for proven treatments such as exercise therapy, weight management, or surgery when indicated.
Hauptrisiken
  • Bleeding and oozing from each bite site for several hours, sometimes up to 24 hours
  • Itching, redness, and irritation at the bite sites lasting days to weeks (15 to 20 percent of patients)
  • Mild anemia if many leeches are used (uncommon with a single session)
  • Local skin infection or, rarely, Aeromonas infection from leech gut bacteria
  • Allergic reaction to leech saliva (uncommon)
  • Small permanent scars at the bite sites
Wer dies nicht in Betracht ziehen sollte
  • Patients taking blood thinners such as warfarin, apixaban, rivaroxaban, dabigatran, or heparin
  • Patients with hemophilia or other inherited bleeding disorders
  • Patients with severe anemia (hemoglobin under 10 g/dL)
  • Patients with a weakened immune system, especially severe neutropenia
  • Patients with an active joint infection (septic arthritis) or skin infection at the planned bite area
  • Patients within 6 months of a knee replacement surgery
  • Pregnant patients (relative caution, especially first and third trimester)
Was Sie Ihren Kliniker fragen sollten
  • Have I tried first-line treatments such as exercise therapy, weight loss, and topical or oral pain medicines, and what does my orthopedist think?
  • What is the realistic chance leech therapy will help me, and for how long?
  • What evidence does the practitioner rely on, and have they treated patients like me before?
  • Are leeches from an FDA-registered supplier and used only once?
  • What antibiotic, if any, will I be given for Aeromonas prevention?
  • What is the cost and is it covered by insurance? (typically not covered as it is off-label)
  • What is the plan if symptoms come back — repeat session, escalation to injections, or surgery referral?
Wann dringende medizinische Versorgung suchen
  • Bleeding from a bite site lasting more than 24 hours or soaking through dressings
  • Spreading redness, warmth, pus, red streaks, or increasing pain around the bite sites
  • Fever above 38.0 C / 100.4 F or chills
  • Sudden severe knee pain, swelling, or inability to bear weight
  • Hives, facial or tongue swelling, throat tightness, or breathing difficulty

Was dies NICHT bedeutet

  • It does not mean leech therapy is FDA-approved for knee osteoarthritis — it is not.
  • It does not mean leeches cure osteoarthritis — the underlying cartilage wear continues; treatment may only reduce symptoms temporarily.
  • It does not mean leech therapy is better than exercise therapy, weight management, physiotherapy, or surgery for appropriate candidates — those remain the standards.
  • It does not mean every patient improves — the trials show meaningful improvement on average, but individual responses vary widely.
  • It does not mean a single session is enough forever — the published effect duration is mostly 3 to 6 months.

Sicherheits-Querverweise

Clinical Profile

Category
musculoskeletal
ICD-10
M17.0, M17.10, M17.11, M17.12, M17.5
Safety tier
low

Evidence Summary

Randomized trials of single-session leech therapy in knee OA are consistent. Michalsen 2003 (n=51) showed WOMAC pain reduction of ~64% at day 7 vs. ~18% for topical diclofenac (P<0.001) — the largest between-group difference at day 7 — with function and stiffness benefits persisting through 3 months. Stange 2012 (n=52) found leech superior to TENS, and Andereya 2008 (n=113) confirmed benefit against a sham/placebo control. A 2014 meta-analysis (Lauche et al., Clin J Pain; 3 RCTs + 1 controlled trial, 237 patients) found strong evidence for immediate pain reduction (SMD -1.05, P<0.01). No serious adverse events; most common AE was prolonged bite-site itching (15-20%). Long-term (≥12 months) data are limited.

Treatment specifics

How many leeches, where they are placed, how long a session lasts, and whether to repeat are clinical decisions made by a qualified provider under institutional protocol — not something to self-administer. Discuss the specifics with a clinician experienced in medicinal leech therapy. (Clinicians: switch the audience selector in the top bar to “Clinician” to view protocol detail.)

Key Trials

  1. Michalsen A et al. (2003), n=51 · PMID 14597456 · ASH analysis →
  2. Stange R et al. (2012), n=113
  3. Lauche R et al. (2014), n=237 · PMID 23446069 · ASH analysis →
Sample sizes of key trials for Knee OsteoarthritisMichalsen A et al. 200351Stange R et al. 2012113Lauche R et al. 2014237
Participants per key trial (n). Larger trials generally carry more statistical weight; case series with unspecified counts are omitted.
Study-design composition of the evidence base for Knee Osteoarthritis3studies
  • RCT: 2 (67%)
  • Meta Analysis: 1 (33%)
Composition of the cited evidence base by study design, from strongest (meta-analysis, systematic review) to weakest (case report). A base weighted toward RCTs and reviews is more reliable.

Detailed Trial Entries

30 trials indexed in the ASH RCT Library with full Study Profile, GRADE rating, and clinical implications:

Forest plot — Cohen's d effect sizes across 11 trials
Cohen's d (pain or primary endpoint)Michalsen A 20031.40 (n=51)Andereya S 20061.10 (n=24)Andereya S 20080.95 (n=113)Lauche R 20140.86 (n=52)Stange R 20120.78 (n=50)Khoshnevisan A 20220.89 (n=80)Sarbaev IS 20190.63 (n=96)Karandikar S 20180.58 (n=60)Cui Y 20240.04 (n=144)Zaidi SM 20090.65 (n=30)American Society of Hirudotherapy Clinical Investigators 20240.82 (n=45)-0.5-0.10.20.60.91.31.6← Favors controlFavors intervention →

Point size proportional to sample size. Positive values favor leech therapy; vertical line = no effect. Cohen's d > 0.8 = large effect; 0.5–0.8 = medium; 0.2–0.5 = small; < 0.2 = negligible.

Contraindications

  • Active anticoagulant therapy (warfarin INR >2.0, DOACs, heparin)
  • Hemophilia or other bleeding disorder
  • Severe anemia (Hb <10 g/dL)
  • Active bacteremia or sepsis
  • Known hypersensitivity to leech salivary proteins
  • Pregnancy (relative — first/third trimester)
  • Immunocompromised state with severe neutropenia
  • Acute septic arthritis
  • Knee replacement (within 6 months)

Related Conditions

Thumb Carpometacarpal (CMC-1) Osteoarthritis

Off-label use with RCT evidence: single-session leech therapy reduces pain and improves function in CMC-1 (basal thumb) OA at 8 weeks.

Lateral Epicondylitis (Tennis Elbow)

Off-label use with two RCTs showing significant pain reduction at 7-12 weeks compared to topical NSAID and conventional physiotherapy.

Plantar Fasciitis

Off-label use with one RCT showing significant heel pain reduction at 6 weeks compared to conservative care.

Fibromyalgia

Investigational adjunctive use; one small pilot suggests transient improvement in tender-point and quality-of-life scores. Not a primary treatment.

Explore the evidence base

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Knee Osteoarthritis — Hirudotherapy Evidence | ASH