We report a case of ruptured distal biceps tendon repaired with a 1-incision Endobutton technique with longitudinal clinical and dynamic magnetic resonance imaging (MRI) follow-up. During the postoperative period, heterotopic ossification (HO) adjacent to the radial tuberosity and retearing of the repaired distal biceps tendon were visible on imaging studies. This prompted gentler rehabilitation. By 1-year follow-up, the patient had returned to preinjury activity levels without additional surgery. In this case, dynamic MRI revealed the space-occupying nature of the focus of HO with resultant narrowing of the radioulnar space. This may have contributed to tendon impingement, retearing, and remodeling. Potential implications for gentler postoperative rehabilitation in patients with this pattern of HO are discussed.