Ten out of 12 complete ruptures of the collateral ligament of the proximal interphalangeal joint were repaired primarily using a suture anchor. Active finger exercise was started gently by taping the injured finger to adjacent one one week postoperatively. All patients returned to their original occupation or sports activities within seven weeks of operation. No patients complained of pain on the involved finger at rest or during movement. There was no instability of the proximal interphalangeal joint on manual lateral stress test postoperatively.