Objective To explore the surgical method and cl inical short-term outcomes of internal fixation combined closed reduction with arthroscope aid in treating patellar fracture. Methods From June 2004 to July 2008, 42 patients with fresh simple patellar fracture underwent internal fixation combined closed reduction with arthroscope aid, included28 males and 14 females, aged 16-59 years (35 years on average). The locations were 19 left knees and 23 right knees. Injury was by traffic accident in 21 cases, by fall ing in 11 cases, by sports in 7 cases and by crush in 3 cases. All the patients had fresh closed fracture, including 38 cases of transverse fracture and 4 cases of stellate fracture. The Lysholm score was 68.60 ± 15.20; the proprioceptive function of the knee joints was (3.72 ± 0.12)°. The time from injury to operation was 3-42 hours (12 hours on average). After the treatment of affil iated injury under the arthroscope, patellar fracture was reduced with manipulation method, fracture was fixed with tensile force screw or modified tension band. Results All incisions obtained heal ing by first intention after operation, 42 patients were followed up for 12-39 months (16 months on average). The X-ray films showed callus at the fracture and the smooth cartilage surface 6-9 weeks (7 weeks on average) after operation. The flexed motion range of knee joint at last follow-up was at normal range in 38 cases, was l imited in 4 cases. Circumference of suffered l imbs 15 cm above the patella was the same as normal ones in 23 cases, atrophied 0.7 cm in 19 cases. There were no breakage of internal fixation and shift of fracture and patellofemoral arthritis at last follow-up. The proprioceptive function of the knee joints was (2.06 ± 0.11)° and the Lysholm score was 95.10 ± 3.92; all showing statistically significant differences when compared with preoperation (P lt; 0.05). Conclusion This treatment method has advantages as follows: mini-wound, early exercises and few compl ications, which can rinse articular cavity and repair the affil iated injury at the same time.