An Evaluation of the Short-Term Results on the Pericalcaneal Joints of the Evans Procedure Applied to Adult Patients with Pes Planovalgus

Background: Adult acquired flat foot deformity (AAFD) is a triplanar deformity characterised by collapse of the medial longitudinal arch. The most frequently used surgical method is the Evans calcaneal osteotomy. It is usually used in the paediatric age group and there are very few studies related to the use of the modified calcaneal osteotomy procedure in adults. The aim of this study was to evaluate the radiographic improvements after this procedure in the adult age group and to investigate whether or not there was real probability of increased arthritis in the STJ and CCJ. Methods: The study included 20 patients who presented at our clinic between January 2020 and June 2022 with the complaint of foot pain and were diagnosed with Grade 2 AAFD. This retrospective study was based on the data in the hospital records system and the patient follow-up forms. Preoperatively and at 1, 6, 12, and 24 months postoperatively, a record was made of calcaneus length, calcaneal slope angle, talocalcaneal angle, medial longitudinal arch angle, and the time to removal of the Kirschner wire. The presence of arthritis in the joint regions was calculated according to the Kellgren–Lawrence classification. Results: According to the data recorded preoperatively and at the postoperative follow-up examinations (mean 1–6–12–24 months), the difference in calcaneal length, calcaneal slope angle, and change in medial longitudinal arch angle were statistically significant (p < 0.001). No statistical significance was found in respect of the development of arthritis according to the preoperative and postoperative measurements for the CCJ and STJ (p = 1.00). Conclusions: The Modified Evans Osteotomy procedure is beneficial and effective in the correction of pes planovalgus. The surgeon must have a good knowledge of anatomy and it must not be forgotten that there could be variations. The probability of arthritis is not as high as has been assumed.