The refinement of technology with improved lighting and smaller optics has made possible new techniques of MCP joint arthroscopy. It is the mastery of the unique anatomy of these different--not just smaller--joints, however, that permits the applications of these new skills. Arthroscopy of the MCP joint permits the diagnosis of pathology not well visualized by other means, and the treatment of these lesions with minimal soft tissue disruption. The authors' experience with arthroscopically aided reduction of fractures of the MCP joint has shown it to be as good as or better than open repair of these fractures. The authors have found the same to be true in treating ulnar collateral ligament injuries of the thumb. Although there is a learning curve with small joint arthroscopy, when the team and surgeon are familiar with the new routines and instruments, the time to accomplish the tasks quickly decreases and is often shorter than that for standard open procedures. The authors' experience suggests that the application of these techniques can allow treatment of MCP pathology with fewer complications than open approaches and may result in improved final function.