Background:Chronic lateral ankle instability (CLAI) is associated with the presence or development of intra-articular pathologies such as chondral or osteochondral lesions, or (O)CLs. Currently, the incidence of (O)CLs in patients with CLAI is unknown.Purpose:To determine the incidence of (O)CLs in patients with CLAI.Study Design:Systematic review and meta-analysis; Level of evidence, 4.Methods:A literature search was conducted in the PubMed (MEDLINE), Embase (Ovid), and Cochrane databases for articles published from January 2000 until December 2020. Two authors independently screened the search results and conducted the quality assessment using the methodological index for non-randomized studies (MINORS) criteria. Clinical studies were included that reported findings on the presence of ankle (O)CLs based on pre- or intraoperative diagnostic measures in patients with CLAI (>6 months of symptoms). Patient and lesion characteristics were pooled using a simplified method. Lesion characteristics included localization and chondral and osteochondral involvement. The primary outcome was the incidence of (O)CLs in ankles with CLAI. A random-effects model with 95% CIs was used to analyze the primary outcome. The distribution of (O)CLs in the ankle joint was reported according to talar or tibial involvement, with medial and lateral divisions for talar involvement.Results:Twelve studies were included with 2145 patients and 2170 ankles with CLAI. The pooled incidence of (O)CLs in ankles with CLAI was 32.2% (95% CI, 22.7%-41.7%). Among all lesions, 43% were chondral and 57% were osteochondral. Among all (O)CLs, 85% were located on the talus and 17% on the distal tibia. Of the talar (O)CLs, 68% were located medially and 32% laterally.Conclusion:(O)CLs were found in up to 32% of ankles with CLAI. The most common location was the talus (85%). Furthermore, most lesions were located on the medial talar dome (68%). These findings will aid physicians in the early recognition and treatment of ankle (O)CLs in the context of CLAI.