Medial Displacement Calcaneal Osteotomy as a Novel Treatment for Recurrent Pain after Kidner Procedure for Accessory Navicular Syndrome
Authors: Kim Jaeyoung , Day Jonathan 
Published: November 2020

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: The accessory navicular is often considered to be related to flatfoot deformity. While the Kidner procedure is commonly utilized in treating painful accessory navicular, its ability to correct flatfoot deformity is debated. Patients may also have recurrent pain due to increased tension of the posterior tibial tendon (PTT) in the setting of an uncorrected flatfoot. In the literature, both PTT lengthening and tendon transfer are techniques described to address this issue with varying success and outcomes. Because medial displacement calcaneal osteotomy (MDCO) is a powerful procedure capable of reducing tension of the medial column and correcting hindfoot valgus deformity, we investigated its use in addressing these symptoms. We report outcomes of a novel use of MDCO in treating patients with recurrent pain following Kidner procedure. Methods: We retrospectively identified 21 patients who underwent MDCO for recurrent pain after Kidner procedure at our institution. MDCO was indicated when patients failed to perform single heel raise due to pain at the PTT attachment site at minimum 6 months following index surgery. Pre- and postoperative radiographic parameters were measured: lateral talo-1st metatarsal angle (Meary’s), talonavicular coverage angle (TNC), calcaneal pitch (CP), and hindfoot moment arm (HMA). Using previously validated cut-offs in describing flatfoot deformity, a Meary’s angle less than -4 degrees was considered a flattened arch, and a HMA more than 3.2mm was considered a valgus heel deformity. Measurements were also performed in x-rays of the contralateral foot to determine whether foot deformity in the involved foot was attributed to Kidner procedure or a preexisting deformity. Pre- and postoperative visual analogue scale (VAS) and FAOS outcome scores were compared to assess for improvement in patient-reported outcomes. Results: The mean age was 25.7 years (range, 21-49) and the mean follow-up was 20.1 months (range, 14-26). The average time from the index surgery was 7.3 months (range, 6-10). Average size of the accessory navicular before excision was 11 mm (range, 4.6-18.3). Concomitant procedures included medial head gastrocnemius recession (n=11), plantarflexion osteotomy of first metatarsal bone (n=1), and talocalcaneal coalition excision (n=1). Radiographically, 12 patients (57%) had a flattened arch and all patients (100%) had heel valgus deformity. All radiographic parameters except Meary’s angle (p=0.885) improved postoperatively. Contralateral radiographs revealed that fifteen patients (71%) had a flattened arch, and 19 patients (90%) had heel valgus deformity. There were no differences between both sides. VAS and FAOS improved significantly (p <0.001). Conclusion: Our data suggest that recurrent pain after Kidner procedure may be related to unaddressed preexisting hindfoot valgus deformity. MDCO provided satisfactory outcomes in relieving this symptom without performing surgery to the PTT. Therefore, MDCO can be a viable option for treatment of recurrent pain following Kidner procedure while potentially avoiding loss of inversion power and donor-site comorbidities associated with PTT lengthening and tendon transfer.