Background: Arthroplasty of the proximal interphalangeal (PIP) joint is a widely performed procedure for patients with osteoarthritis. Its use in the index finger is often discouraged due to concerns over implant longevity and stability secondary to coronal forces this digit is exposed to during pinch. Methods: We analyzed 47 consecutive index finger silastic interposition arthroplasties, performed through a dorsal approach, at a mean follow-up of 5.15 years. Results: Only 2 patients had ulnar deviation greater than 15°. The reoperation rate was 12.8%, with only 1 finger requiring arthrodesis. The mean Visual Analog Scale score was 1.1; and of the whole series, only 1 patient would retrospectively have preferred a fusion. Conclusions: Our series shows that excellent functional results and patient satisfaction can be gained using silastic PIP joint arthroplasty in the index finger. We would advocate offering this procedure, especially in lower demand patients as an alternative to arthrodesis, with the benefit of providing good pain relief while preserving movement.