## 1 Introduction  
Clinically, the term \"pes cavus\" is used to present a kind of deformity of the medial longitudinal arch (MLA), which has a prominent anatomical characteristic of its abnormal elevation. The accurate description of pes cavus includes numerous foot deformities in multiple planes. At the skeletal level, pes cavus is characterized by plantar flexion of the first metatararsal, wedge-shaped forefoot bones, and bony prominences on the dorsal aspect of the navicular and cuboid bones. These characteristics commonly result in foot pronation, excessive supination, claw toes, and other foot deformities on the foot level. Individuals with pes cavus may experience increased stiffness and reduced shock absorption in the lateral aspects of the forefoot and rearfoot, as well as heightened pressure on the foot [1], that can result in increased foot instability, muscle or ligament overstrain, and dysfunction, which can potentially increase the risk of an ankle injury. Specifically, the inward rolling of the foot and ankle caused by the high arch structure can lead to lateral overloading of the foot and ankle structures, potentially compromising foot and ankle function. These effects can hinder athletic performance and increase the likelihood of injury [2]. As a result, the neural and muscle control of the ankle joint can be weakened [3]. The true incidence rate is not yet clear. According to the relevant literature, the incidence rate of pes cavus appears to increase with age, ranging from 2% at 3 years old to 7% at 16 years old [4]. The incidence rate of pes cavus may be higher in the adult population, estimated to be between 10.5% and 25% [5; 6]. An estimated 60% of individuals with cavus feet experience foot pain, including conditions such as metatarsalgia, sesamoiditis, or plantar heel pain. It is thought that these conditions are linked to the atypical distribution of pressure on the sole [7]. The etiology of pes cavus encompasses several factors, including neurogenic, congenital, traumatic, and idiopathic causes. Contributing factors to the development of pes cavus involve muscle weakness and imbalances resulting from neuromuscular disorders, residual equinovarus foot present since birth, bone deformities following trauma, peroneal tendon rupture, plantar fascitis, as well as a shortened Achilles tendon. Currently, based on clinical observations, the medical community generally recognizes pes cavus as one of the results of neurological diseases, and most cases are idiopathic cases that include genetic predisposition [8]. Due to the complex etiology and developmental mechanism of pes cavus, a unified treatment plan cannot be determined in clinical practice. For severe pes cavus patients, such as those with severe hindfoot varus caused by neurological diseases, surgical treatment is necessary since conservative physical therapy cannot solve the endogenous problem [9], but it can play a preventive role [1]. For mild and non-progressive idiopathic pes cavus patients, physical therapy is also a good choice [10]. In real life, there are many pes cavus patients like this, and physical therapy may have better therapeutic effects [9], helping to alleviate pes cavus pain, and correct foot posture and gait. In the clinical treatment of pes cavus, there is a strong emphasis on joint preservation therapy, especially in patients with pes cavus who have flexible joints, but the evidence base for such treatment is extremely limited [11]. Considering the slow progression of pes cavus and its long-term adverse effects on foot biomechanics, the medical community generally recommends timely early intervention for pes cavus. It is helpful for clinical treatment, and it can also play a certain role in the operation of joint preservation [12]. Compared with surgical intervention, conservative physical therapy reduces the risk of surgery. There are many physical therapy methods used to treat pes cavus, among which foot orthotics are the most common treatment method.