Osteoid osteoma (OO) is a benign tumor that it is not generally seen in the foot and even less frequently in the phalanx (2–4%). The diagnosis when its location is intra-articular is a challenge and often delayed because the symptoms mimic a real arthritis. We report a clinical case involving a 16-year-old male patient who complained of persistent pain of the interphalangeal joint (IPJ) of the left hallux. A juxta-articular OO of the condyle of the proximal phalanx was identified. The patient underwent surgery that included tumor removal preserving the articular cartilage. After a non-complete nidus resection, there was a recurrence. The patient underwent surgery with a removal en-block of the distal part of the proximal phalanx and fusion of the IPJ with interposition of a tricortical autograft. After a follow-up of 30 months, the X-ray showed total arthrodesis of the joint without signs of recurrence or pain.