Knee dysfunction secondary to dislocation of the fabella.

The fabella, a sesamoid bone in the lateral head of the gastrocnemius muscle occurring in 10% to 30% of individuals, is rarely considered a possible cause of knee dysfunction. When noted, the fabella is occasionally mistaken radiographically for an intraarticular ossified fragment; however, symptomatic conditions of the fabella have been well documented in the literature. This is a report of symptomatic dislocation of an enlarged fabella in a 37-year-old man. In a review of the literature of various lesions of the fabella, disability related to dislocation seems not to have been previously reported.