Sesamoid bones of the hand: A multicenter study

OBJECTIVES: This study aims to document a detailed investigation on the sesamoid bones (SBs) of Turkish subjects from different parts of Turkey in a multi-center study, in both hands, according to gender, frequency and divisions of the bones’ coexistence and bilaterality by radiography. PATIENTS AND METHODS: This retrospective and three-centered study was performed between June 2010 and April 2012. Sesamoid bones were examined by anteroposterior and oblique X-rays of 1,444 hands of 772 subjects (367 males, 405 females; mean age 42.7 years; range, 18 to 87 years). All X-rays were evaluated by at least two independent observers. In controversial circumstances, at least three observers together gave the final decision by consensus. RESULTS: Metacarpophalengeal (MCP) joint of the thumb (MCP 1) had sesamoid in all subjects (100%) and it was seen bilaterally. The prevalence of the SB was 42.8% in the second MCP joint (MCP 2) in 772 subjects and 36.6% in 1,444 hands, 1.6% in the third MCP joint (MCP 3) for the subjects and 1.1% for the hands, 0.1% in the fourth MCP joint (MCP 4) for the subjects and 0.1% for the hands, and 72.5% in the fifth MCP joint (MCP 5) for the subjects and 62.5% for the hands. The prevalence of SB in the first interphalangeal joint (IP 1) was 21.8% and SB was detected in 18.6% of the hands. Sesamoid bones of the MCP 2, MCP 5, and IP 1 was recorded more frequently in females. Sesamoid bone of the same joints (MCP 2, MCP 5 and IP 1) was detected more frequently bilaterally than unilateral right side and more frequently unilaterally on right side than unilateral left side. CONCLUSION: The distribution of SBs varies according to hand regions, gender, and side. Having knowledge of the locations and the rate of bilaterality of SBs may assist clinicians in both clinical and radiological diagnoses.