OBJECTIVE: To analyze the long-term (5-25 years) functional and radiologic results of surgically treated intra-articular fractures of the distal femur. DESIGN: Retrospective study. SETTING: University hospital. PATIENTS AND METHODS: Sixty-seven surgically treated consecutive patients with 67 intra-articular distal femoral fractures were included in this study. All fractures were classified according to the AO classification. There were 36 men and 31 women. The mean age at time of accident was 45 years (range 16-94 years). There were 38 patients with isolated fractures and 29 with multiple fractures. Median hospital stay was 23 days (range 12-330 days). A 1-year follow-up was done in all 67 patients. Thirty-two of these patients were also seen for an additional long-term follow-up visit. Functional results of these 32 patients were graded using the Neer and HSS knee scores. Radiologic results were graded using the Ahlbäck score. Statistical analysis was performed by means of the SPSS data analysis program. RESULTS: At 1-year follow-up in 40 of 65 patients (62%), the fracture was fully healed, in 22 patients (34%) a fixation callus still existed, and 1 patient had a nonunion. In 2 patients, an arthrodesis was performed. The mean knee range of motion was 111 degrees (range 10-145 degrees). After a mean follow-up of 14 years (range 5-25 years), the mean knee range of motion was 118 degrees (range 10-145 degrees). The Neer score showed good to excellent results in 84% of the patients, and the HSS knee score showed good to excellent results in 75% of the patients. Patients with isolated fractures scored significantly better functionally (Neer/HSS 90 points) compared with those with multiple fractures. The Ahlbäck score showed a moderate to severe development of secondary osteoarthritis in 36% of all patients. Seventy-two percent of these patients still scored a good to excellent functional result. Seven patients (10%) had local complications in the form of a deep wound infection. Five of these patients were treated successfully, whereas 2 had a chronic infection that subsequently led to an arthrodesis. CONCLUSION: Surgical treatment of monocondylar and bicondylar femoral fractures shows good long-term results after open reduction and internal fixation. Knee function increases through time, though the range of motion does not increase after 1 year. The presence of secondary osteoarthritis does not mean less favorable functional results in most patients.