Subtalar Arthroereisis Using Kalix® Sinus Tarsi Implant for Pediatric Flexible Flatfoot / 대한정형외과학회잡지

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the radiographic and clinical outcomes of subtalar arthroereisis as a method of treatment for pediatric flexible flatfoot. MATERIALS AND METHODS: We retrospectively investigated 14 feet among 10 patients with flexible flatfoot, who were treated with a subtalar arthroereisis using a sinus tarsi implant between March 2007 and June 2012. Radiographically, the talo-1st metatarsal angle, talar declination, and calcaneal pitch angle have all been measured on lateral radiographs. The talo-navicular coverage angle and talo-1st metatarsal angle was measured on anteroposterior (AP) radiographs and tibio-calcaneal angle was assessed by hindfoot alignment view. Visual analogue scale (VAS) pain scores and the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scores were used for clinical evaluation. RESULTS: The mean follow-up was 48.7 months (16–98 months), and the mean age was 11.6 years (6–19 years). Radiographically, the mean pre-operative and postoperative values measured by the lateral foot radiograph were −25.1° and −7.5° for talo-1st metatarsal angle, 37.4° and 23.2° for talar declination, and 8.3° and 15.0° for calcaneal pitch angle, respectively. The mean preoperative and postoperative values measured by foot AP radiograph were 23.0° and 11.9° for talo-navicular coverage angle and 17.2° and 9.0° for talo-1st metatarsal angle, respectively. Moreover, tibio-calcaneal angle improved from valgus 17.4° on average to 4.5° on average. Clinically, the VAS score and AOFAS score was improved from 5.8 to 1.5 and from 61.8 to 90.4, respectively. Complication was sinus tarsi pain that occurred in 5 cases (35.7%). CONCLUSION: We achieved a satisfactory correction of pediatric flexible flatfoot deformities via subtalar arthroereisis, using a sinus tarsi implant with favorable radiographic and clinical measures. However, high potential complication rate of postoperative sinus tarsi pain on weight-bearing should carefully be considered.