We set out to evaluate quality of reporting of data related to external validity from randomized controlled trials (RCTs) assessing treatment interventions for active venous leg ulcers. Using a systematic review study design, we identified 144 full-text RCTs of treatment interventions, where the wound was assessed and published in English from 1998 to 2018. We found that the median study sample size was 75.5. Weighted mean wound size was 13.22 cm2 and weighted mean wound duration was 22.20 months. Forty-six (32%) reported numbers screened for eligibility and 27 (19%) reported the number who declined to participate; 19 (13%) reported on patient ethnicity; 60 (42%) reported comorbidities; and 5 (4%) reported current medication use. When reported, 60/102 (59%) excluded patients with an ankle-brachial pressure index <0.8; 68/135 (50%) were conducted in Europe, 6/135 (4%) in Asia, and 74/104 (71%) were conducted in outpatient facilities; 3 (2%) reported socioeconomic factors and 88 (61%) reported on adverse events. We concluded that there is inadequate reporting of data related to external validity in reports of RCTs assessing venous leg ulcers treatment interventions. Significant variability exists in the ankle-brachial pressure index cutoff point for inclusion or exclusion, making generalizability difficult to assess.