Orthopedic fixation devices and methods of installing the same. The orthopedic fixation device may include a coupling element and a bone fastener, whereby the bone fastener can be loaded into the coupling element through the bottom of a bore in the coupling element and a retention member is configured to allow polyaxial rotation of the bone fastener and also to lock the bone fastener in place upon application of a force on a saddle and clamp in the coupling element.