ObjectiveTo evaluate the effectiveness of the modified intramedullary fixation with two Kirschner wires for extra-articular fracture of the proximal phalangeal base. MethodsBetween June 2012 and November 2015, 18 cases (18 fingers) of fresh extra-articular fracture of the proximal phalangeal base were treated, including 16 males and 2 females with an average age of 31 years (range, 21-57 years). The causes included strike injury in 10 cases, fall injury in 4 cases, mechanical injury in 1 case, twist injury in 1 case, crush injury in 1 case, and cutting injury in 1 case. The injured fingers were little finger in 16 cases, ring finger in 1 case, and index finger in 1 case. Of the 18 cases, 17 had closed fractures and 1 had open fracture. X-ray film showed transverse fracture in 14 cases and transverse-oblique fracture in 4 cases. The time between injury and operation was 3 hours to 4 days (mean, 2 days). After anatomical reduction, two Kirschner wires were used for intramedullary fixation. Functional exercises were done at 2 days after operation. The Kirschner wires were removed at 4 weeks after operation. ResultsAll the wounds healed by first intention. There were no deformation, loosening or breakage of Kirschner wires, and pin tract infection. Postoperative X-ray films showed anatomical reduction of fracture in all cases; no re-displacement happened, and clinical healing was obtained at 4 weeks; bony union was obtained at 8 weeks. All patients were followed up 6-12 months with an average of 8 months. There was no pain in the metacarpophalangeal joint; the range of motion was (88.1±2.3)° at 3 months after operation, showing no significant difference when compared with normal side [(88.8±2.6)°] (t=1.73, P=0.10). The finger flexion and extension were normal; according to the criteria of total active motion of finger, the results were excellent in all cases. ConclusionThe technique of modified intramedullary fixation with two Kirschner wires for extra-articular fractures of the proximal phalangeal base has the merits of convenient operation, little injury, reliable fixation, and excellent effectiveness. This technique is conducive to the recovery of hand function due to the early functional exercises.