OBJECTIVE: Functional ankle instability is characterized by proprioceptive deficits, decreased neuromuscular control, and recurrent ankle sprains, which severely affect the patient’s daily activities. Proprioception as an important aspect of functional ankle instability, whether there is a deficit in proprioception compared to contralateral limbs and healthy individuals is not known. Therefore, this systematic review aims to analyze the proprioceptive characteristics of functional ankle instability. METHODS: We searched the CNKI, PubMed, Web of Science, EBSCO-host, Ovid, and EMbase databases from inception to February 2022 to collect observational studies about the proprioception characteristics of functional ankle instability, exposure to at least one proprioceptive deficit in kinesthesia, joint position sense, and force sense. Two researchers independently screened the articles according to the inclusion and exclusion criteria, and evaluated the quality of the included studies according to the Newcastle-Ottawa Scale and the cross-sectional study quality evaluation form developed by the American Institute for Healthcare Research and Quality, and extracted absolute errors relating kinesthesia, joint position sense, and force sense to set target. Metaanalysis was then performed using RevMan 5.3 software. RESULTS: A total of 26 observational studies were included, including 4 cohort studies, 6 case-control studies and 16 cross-sectional studies, all of which were of medium to high quality. Meta-analysis results showed that patients with unilateral functional ankle instability had inversion kinesthesia defects compared with the contralateral limbs and healthy people (SMD=0.53, 95%CI:0.36-0.71, P < 0.000 01). Compared with the contralateral limb, patients with unilateral functional ankle instability had the defect of inversion joint position sense (active vs. passive replication) (SMD=1.60, 95%CI:0.77-2.43, P=0.000 2). Compared with healthy people, unilateral functional ankle instability patients had the defect of inversion joint position sense (active vs. passive replication) (SMD=0.66, 95%CI:0.25-1.07, P=0.002). Compared with healthy people, unilateral functional ankle instability patients had the defect of active eversion joint position sense (SMD=3.68, 95%CI:1.85-5.52, P < 0.000 1). Compared with healthy people, unilateral functional ankle instability patients had the defect of passive eversion joint position sense (SMD=-0.61, 95%CI:-1.19 to -0.02, P=0.04). There was no significant difference between patients with unilateral functional ankle instability and healthy subjects in plantarflexion joint position sense (active vs. passive replication) (SMD=0.80, 95%CI:-0.19 to 1.79, P=0.11). There was no significant difference between patients with unilateral functional ankle instability and healthy subjects in dorsiflexion joint position sense (active vs. passive replication) (SMD=0.86, 95%CI:-0.01 to 1.74, P=0.05). Patients with unilateral functional ankle instability had coronal plant motion force sense deficits compared with healthy individuals (SMD=1.35, 95%CI:0.85 to 1.85, P < 0.000 01). Subgroup analysis showed that patients with unilateral functional ankle instability had greater eversion force sense error than those with inversion force sense error compared with the healthy population (P=0.44). CONCLUSION: Compared with the contralateral limbs, patients with unilateral functional ankle instability have the defects of inversion kinesthesia. Compared with healthy people, unilateral functional ankle instability patients have the defects of inversion kinesthesia, active and passive inversion joint position sense, active eversion joint position sense and force sense of inversion and eversion. [ABSTRACT FROM AUTHOR]