PAPER 094: OPEN REDUCTION AND INTERNAL FIXATION OF THE SYMPTOMATIC TYPE II ACCESSORY NAVICULAR

Abstract

Purpose: Currently, the modified Kidner procedure is recommended to treat the symptomatic accessory navicular that fails nonoperative management. Some foot and ankle specialists have cautioned that excision of the accessory navicular can lead to a progressive increase in pain and loss of the longitudinal arch. As a result, they have recommended ORIF of the symptomatic accessory navicular as a surgical alternative. To our knowledge, the only references to this surgical alternative in the orthopedic literature are two technique papers.

Method: Between 1999 and 2005, 17 patients were treated with symptomatic type II accessory naviculars that failed nonoperative measures. A standard treatment algorithm was followed:

• accessory naviculars of adequate size underwent an ORIF (10), and

• accessory naviculars of smaller size underwent a modified Kidner procedure (7).

Corrective osteotomies and/or soft-tissue procedures were performed concomitantly in nine patients to address pes planus. Pre- and postoperatively, patients were assessed radiographically. Preoperative MRI scans were analyzed to see if there was any correlation between MRI findings and success of ORIF. Patients were evaluated with the AOFAS midfoot clinical rating system (max 100 points).

Results: In the patients treated with ORIF, average follow-up was 31 months. The average AOFAS mid-foot score improved from 49 to 89 points. Radiographic analysis suggested an 80% union rate. However, only one patient out of ten (10%) undergoing ORIF with subsequent nonunion was symptomatic and her pain resolved after screw removal. In the patients treated with excision, average followup was 48 months. The average AOFAS score improved from 45 to 78 points. Three of seven feet (43%) treated with accessory navicular excision had persistent midfoot pain at last followup with clinical and radiographic signs of progressive loss of the longitudinal arch. Twelve patients had a preoperative MRI of the foot with all showing edema suggesting an injury to the synchondrosis. We found no correlation between MRI findings and success of ORIF of the accessory navicular.

Conclusion: As suggested by previous technique papers and this study, ORIF of the symptomatic type II accessory navicular may have merit. We anticipate that this study will prompt a comprehensive multicenter evaluation of this technique.