To identify risk factors for fixation failure, report patient outcomes, and advise on modifications to the surgical technique for fibula nail stabilization of unstable ankle fractures. Retrospective review. Academic orthopaedic trauma unit. All 342 patients were identified retrospectively from a prospectively collected single-center trauma database over a 9-year period. Unstable ankle fractures managed surgically with a fibula nail. The primary short-term outcome was failure, defined as any case that required revision surgery because of an inadequate mechanical construct. The mid-term outcomes included the Olerud-Molander Ankle Score and the Manchester-Oxford Foot Questionnaire. Twenty failures occurred (6%), of which 7 (2%) were due to device failure and 13 (4%) due to surgeon error. Of the surgeon errors, 8 consisted of inappropriate weight-bearing after syndesmotic diastasis, and 5 were due to inadequate fracture reduction or poor nail placement. Proximal locking screw (PLS) pull-out was the cause of all device failures. Positioning the PLS >20 mm above the plafond significantly increased failure risk (P = 0.003). At a mean follow-up of 5.1 years (range, 8 months-8 years) the median Olerud-Molander Ankle Score and Manchester-Oxford Foot Questionnaire were 80 (interquartile range, 45) and 10.94 (interquartile range, 44.00), respectively. Patient outcome was not negatively affected by the requirement for revision surgery. The fibula nail offers secure fixation and good patient-reported outcomes for unstable ankle fractures. Appropriate postoperative management and surgical technique, including careful placement of the PLS, is essential to minimize construct failure risk. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.