Synovial cysts are benign tissue masses that develop near joints and tendons as a result of fluid leakage. They can be difficult to eradicate, and adjacent tendon and joint surfaces can complicate their treatment. We retrospectively analyzed the data from 4 consecutive patients who had undergone hallux interphalangeal fusion from January 2009 to December 2010. Of the 4 patients, 3 were male and 1 was female, with a mean age of 55 +/- 22 (range 26 to 79) years. These 4 patients had developed painful interphalangeal arthritis with radiographic cystic changes of 1 to 4 years' duration. All patients were treated at a single facility, with surgical fixation of the joint performed by insertion of a single 43-mm headless lag screw across the in-terphalangeal joint. A final postoperative follow-up examination was performed at 22 +/- 7 (range 14 to 30) months postoperatively. The mean American Orthopaedic Foot and Ankle Society hallux functional scores increased significantly from 70.8 +/- 6.1 preoperatively to 90.5 +/- 5.2 postoperatively (p < .01). No complications were observed, and complete interphalangeal joint fusion was observed at a mean of 9.2 +/- 1.2 weeks. In conclusion, these preliminary data suggest that arthrodesis is an alternative effective treatment of symptomatic synovial cyst formation localized to the hallux interphalangeal joint. Published by Elsevier Inc. on behalf of the American College of Foot and Ankle Surgeons.