The Pain Genetics Lab has reviewed the transgenic knockout technique as applied to pain research on a number of occasions (e.g., see this review), including a discussion of its confounds and limitations. However, in the aggregate, we believe that this is an important and useful technique to define the molecular "players" in pain, and there is definitely something to be gained from a consideration of all the genes whose ablation has been shown to result in a "pain phenotype." Therefore, we have created the Pain Genes Database, an interactive html-based web browser (updated monthly) of the phenotypes of all knockout mice tested for pain!
Note that the Pain Genes Database has not been updated since 2015. Any party interested in taking over the database is encouraged to contact Dr. Mogil.