PURPOSE: The purpose of our study was to identify factors affecting the outcome after arthroscopically assisted repair of peripheral triangular fibrocartilage complex (TFCC) tears. TYPE OF STUDY: Retrospective case series. METHODS: Thirty-five patients who underwent arthroscopic repair of traumatic TFCC tears were enrolled in this study (mean age, 34 +/- 12 years; 22 female and 13 male patients; mean follow-up, 29 months; range, 6 to 82 months). Patients with TFCC tears associated with distal radius fractures, or significant wrist bone or neurovascular pathology were excluded from the study. The Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire score was used as the primary variable during statistical analysis to identify factors determining outcome. RESULTS: The DASH score in this study was 12 +/- 12 points. A significant correlation was found between the age of the patient and the DASH score, indicating that older age has a significant negative effect on functional outcome. Significant correlations were also found between the DASH score and (1) decreased percentage of grip strength compared with the healthy side, (2) decreased supination, and (3) positive postoperative ulnar variance. CONCLUSIONS: Age-related degenerative changes in the wrist might contribute to poor outcome and a TFCC tear resulting from minor or repetitive trauma. Loss of wrist rotation, grip strength, and ulnar positive variance are factors that are correlated with poor outcome. LEVEL OF EVIDENCE: Level IV.