Any suggestions for overcoming reduced hand function?

I suffered an injury to my non-dominant hand just over a year and a half ago and it was severe enough that I wasn't able to recover full function with it after surgery and physical therapy. Specifically, the range of motion of the ring finger is limited and that has had a large impact on gripping. While the use of one-handed weapons hasn't been impacted and longsword only slightly so, I want to be able to further my experience with rapier by learning to use buckler and dagger along with it. If anyone has any suggestions on ways to supplement my hand's grip, I would appreciate them being shared.