Chronic elbow pain has several causes. Instability pain is one of the differential diagnosis. Posterolateral rotatory instability (PLRI) of the elbow results from lateral collateral ligament (LCL) insufficiency. This instability has been recognized in association with trauma of the elbow. The standard treatment of LCL insufficiency is ligament reconstruction with a tendon graft. Treatment outcome of LCL reconstruction in atraumatic PLRI cases has been rarely reported. This study reports the results of LCL reconstruction in patients with chronic lateral elbow pain from atraumatic PLRI.