To evaluate the long-term results of a prospective, longitudinal case series of untreated, traumatic triangular fibrocartilage complex (TFCC) tears found in displaced distal radial fractures. Between 1995 and 1997, 51 patients (24 men, 27 women; age, 20-57 y) with a displaced distal radius fracture had wrist arthroscopy to identify associated injuries. Forty-three patients had complete or partial tears of the TFCC, which were not treated. All patients were contacted in 2010, 13-15 years after the injury. One patient had had a TFCC reattachment due to painful distal radioulnar joint instability and was excluded. Thirty-eight patients returned for a radiographic and clinical follow-up that recorded strength, distal radioulnar joint laxity, range of motion, pain scale score, and subjective and objective outcome scores. After 13-15 years, 17/38 patients were lax in the distal radioulnar joint. The mean grip strength was worse in the patients with a lax distal radioulnar joint (83%, SD 15 of the contralateral side vs 103%, SD 33). The median Gartland and Werley score was 5 (good; range, 0-15) in the lax group compared to 1 (excellent; range, 0-9) in the non-lax group, and the median Disabilities of the Arm, Shoulder, and Hand scores were 14 (range, 0-59) and 5 (range, 0-70) respectively. In this 13-15 year, prospective, longitudinal outcome study of the natural course of TFCC tears associated with distal radius fracture, only 1 patient had been operated on for painful instability since the injury. The subjective and objective results did not provide evidence that a TFCC injury would influence the long-term outcome. However, trends were found and, by speculation, the low number of patients in the series and the risk for a type II error could be the cause of absent statistically significance. Larger, preferably prospective, randomized studies are needed to find out whether a more aggressive treatment is beneficial. Diagnostic I.