[Application of modified internal fixation and fusion for type Ⅱ painful accessory navicular in adults]

To explore the effectiveness of modified internal fixation and fusion in treatment of type Ⅱ painful accessory navicular (PAN) in adults.

Between January 2016 and December 2017, 29 patients (37 feet) with type Ⅱ PAN were treated with modified internal fixation and fusion. There were 12 males and 17 females with an average age of 41.4 years (range, 18-50 years). The injury caused by sprain in 24 cases and no obvious inducement occurred in 5 cases. All patients received conservative treatment for more than 6 months with no significant improvement. The effectiveness was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) score before operation and at last follow-up. The inclination angle of calcaneus, the first metatarsal angle of talus, the inclusion angle of talonavicular joint, and the second metatarsal angle of talus were measured on X-ray films.

Superficial infection of incision occurred in 1 case after operation, and the incision healed after enhanced dressing change. The incisons of the other patients healed by first intention. There was no deep infection or osteomyelitis. All patients were followed up 12-33 months (mean, 25.1 months). X-ray films showed that the articular surfaces healed at 2-5 months after operation, with an average of 3.4 months. No loosening or rupture of internal fixator was found during the follow-up. At last follow-up, the pain, function, alignment scores, and total score of AOFAS were significantly improved when compared with those before operation (P<0.05). The inclusion angle of talonavicular joint, the first metatarsal angle of talus, and the second metatarsal angle of talus were also significantly improved when compared with those before operation (P<0.05). But there was no significant difference in the inclination angle of calcaneus between pre- and post-operation (t=1.097, P=0.276).

Modified internal fixation and fusion in treatment of type Ⅱ PAN can effectively relieve the symptoms and obtain good recovery of feet function with less complications.