In details template (details.tpl) search for:

<!-- BEGIN SIMILAR --> <a href="{TRACKLINKURL}" {EXTERNALLINKS}>{LINKTITLE}</a>, <!-- END SIMILAR -->

change to:

<!-- BEGIN SIMILAR -->IF {LINKURL}><a href="{TRACKLINKURL}" {EXTERNALLINKS}>{LINKTITLE}</a>,<OTHERWISE><a href="{LINKDETAILSURL}">{LINKTITLE}</a></IF> <!-- END SIMILAR -->