Chronic proximal interphalangeal (PIP) joint instability is a rare and difficult problem to treat, with the main options including collateral ligament reconstruction and joint arthrodesis. To date, there are minimal described techniques for collateral ligament reconstruction. We describe a novel technique utilizing a slip of the flexor digitorum superficialis (FDS), harvested through a single minimal incision. This technique can be used for collateral ligament reconstruction with multiple applications, including chronic recurrent PIP joint dislocations and instability during PIP joint arthroplasty.