Litwiniuk 2012.

Methods	Prospective cohort study Setting: attending outpatient phlebology clinic Country: Poland Duration of follow‐up: 4 weeks Treatments: all participants had amnion foetal membrane treatment (plus hydrocolloid and compression), shown to be an inhibitor of MMP activity (i.e. potential confounder)
Participants	25 participants with VLUs (CVLU; venous insufficiency aetiology, further confirmed by a duplex‐Doppler ultrasound examination) Mean age: 76.3 (SD 12) years Sex (M:F): 9:16 Stage of ulcer: C6 according to the CEAP classification Wound infection: excluded if evident signs of infection (odorous, purulent exudates, wound necrosis and significant pain) Number of wounds: not reported Inclusion criteria: chronic wound (> 6 months); surface area 10‐100 cm²; delayed healing (healing rate < 10%/week) regardless of ≥ 2 weeks' treatment (screening period) of hydrocolloid dressing and effective compression Exclusion criteria: evident signs of wound infection (odorous, purulent exudates, wound necrosis and significant pain), active DVT, leg ischaemia with ankle/brachial index < 0.8, poor tolerance of compression, pregnancy, diabetes and other systemic diseases (particularly significant heart insufficiency) in unstable stage and malignancy
Prognostic factors	MMP‐2 (continuous data); activity (ng/mL). Measurement method quantitative gelatin/SDS zymography Time of measurement: baseline and day 28 Wound fluid sampling method: not stated
Notes	Limited data collection, no results. Risk of bias assessments available on request