Prospective Early Clinical, Radiological, and Kinematic Pedobarographic Analysis Following Subtalar Arthroereises for Paediatric Pes Planovalgus

Introduction Arthroereises implants mechanically block eversion and limit subtalar motion. They are used in children with pes planovalgus in order to correct the valgus deformity. In this study, we aimed to objectively assess children with flatfoot before and after the insertion of the Kalix II implant, clinically, radiologically and by kinematic pedobarographic analysis. Materials and methods Six children (12 feet) were treated by the insertion of the Kalix II implant (Integra LifeSciences, Plainsboro, NJ). Patients completed the Manchester Oxford Foot Questionnaire (MOXFQ) preoperatively and at six months post operatively. Radiological outcome was assessed by lateral (L) and anterior posterior (AP) foot weight-bearing radiographs taken pre operatively and post operatively. Pedobarographic data was obtained pre operatively and at six months post operatively using a 1 meter RS Scan Footscan (RSscan International, Olen, Belgium) pedobarograph. In addition, patients underwent gait analysis pre and post operatively. Results Mean age was 11.05 +/-3.24 years (range 6.2 to 15.5 years). In all cases, screw removal was carried out at between 15 to 18 months post insertion. The mean pre op MOXFQ score was 55.3 +/-9.68 which reduced to 34.3 +/-15.66 post operatively with a p value < 0.00001 which was statistically significant. Mean Meary's angle preop was -15.21+/-5.51 degrees which corrected to -7.57+/-4.62 post op with a p value=0.00001. The mean calcaneal pitch before surgery was 11.96+/-3.8 which increased to 14.98+/-3.85 with a p value =0.00067. The first MTH: fifth MTH peak pressure ratio pre operatively was 4.53+/-2.78 which was found to reduce significantly post operatively to 1.35+/-0.97 (p=0.04), indicating a lateral shift of the foot pressures. Conclusion There were statistically significant improvements in the patient-reported MOXFQ, radiological improvements, and pedobarographic changes, indicating a lateral shift of the foot pressures. There were no complications.