Background The aim was to report the long-term functional and radiologic outcomes in patients treated for recurrent posterolateral elbow joint instability using an ipsilateral triceps tendon graft. Methods We included 18 patients previously treated for posterolateral elbow joint instability and evaluated for clinical results in 2003. Fifteen patients were examined with a mean follow-up period of 19 years (range, 17-22 years). We performed the clinical follow-up with clinical examination of stability, range of motion, pain score on a visual analog scale, Mayo Elbow Performance Score, and Danish version of Oxford Elbow Score. Furthermore, conventional anteroposterior and side-view radiographs of the elbow were obtained to evaluate osteoarthritis, calcifications in the ligaments, and joint subluxation. We evaluated the radiographs by the size of osteophytes, joint space narrowing, and subchondral sclerosis and classified the findings into 3 categories: no osteoarthritis, osteoarthritis, and severe osteoarthritis. Results All patients had a clinically stable elbow. None had pain while inactive or locking of the joint, and 4 had decreased range of motion. Two patients had a positive pivot-shift stress test, indicating laxity. The mean Mayo Elbow Performance Score was 93 (range, 70-100). The mean Oxford Elbow Score was 45. We observed 5 patients with osteoarthritis and 1 patient with severe osteoarthritis. Conclusion The technique reported by Olsen and Søjbjerg in 2003 gives good long-term results in the treatment of symptomatic posterolateral elbow joint instability, though the development of elbow joint osteoarthritis may decrease the surgical result in the coming years.