Introduction: Osteoarthritis (OA) and age-related degeneration (ARD) are stimulants for the development of the fabella in the knee joint. This meta-analysis updates previous studies and reviews on the prevalence of the fabella in OA or ARD knee joints. In addition, it provides a quantitative estimation of the fabellar prevalence in knees having OA and ARD. Methodology: Twenty studies comprising of data from 11,056 knee joints were included in the analysis, consisting of 6,819 Knees of OA subjects (including those with age more than 40 years) and 4,237 knees of non-OA subjects (including less than 40years) knees, respectively. 2,434 knees had fabellae present in OA subjects (including more than 40years), and 844 fabellae were present in non-OA subjects (including less than 40years). The Odds and Risk Ratios were calculated. Sensitivity analysis and cumulative analysis were conducted to assess the robustness of the findings. Results: Prevalence of fabella was found to be higher in OA knees, where the Risk Ratio of developing fabella was 2.50 (2.07-3.01). Compared with this, the Risk Ratio for the incidence of fabella in OA with ARD knee was 1.84 (1.66-2.03). The bilateral occurrence of fabella was more common than unilateral. The risk of developing fabella in individuals aged less than forty-year was 63% less than individuals aged more than forty years. Conclusion: OA and ARD would increase the prevalence of fabella by 84%, thus acting as stimulants and risk factors for ossified fabella.