In surgical interventions, randomization and blinding may be difficult to implement. In this situation, non-randomized prospective studies (EPNR) can generate the best evidence. The objective of this study is to evaluate, by means of the scale proposed by Downs & Black, the quality of EPNR published in our country and to assess the interobserver reproducibility of this scale. EPNR published in Acta Ortopedica Brasileira and Revista Brasileira de Ortopedia until 2011 and prior to 2006 were included. Two of us independently applied the Downs & Black scale. The studies were stratified by period of publication, journal and type of intervention. The scores obtained were considered to assess the reliability of the scale and groups comparison. 59 studies were considered, seven excluded during the assessments. There were no differences between the scores, except for the type of intervention, which showed better methodological quality for studies involving clinical interventions (p < 0.001). The correlation coefficient for the Downs & Black score was 0.79 (95% CI 0.65 to 0.88), demonstrating good reliability. EPNR present methodological quality similar when stratified by the periodic publication and publication period. Studies with clinical interventions have better methodological quality. The Downs & Black scale shows good interobserver reproducibility.