What tibial sesamoid position indicates erosion of crista from the 1st metatarsal head?

What tibial sesamoid position indicates erosion of crista from the 1st metatarsal head?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (D)

The main idea is that how far the tibial sesamoid has translated relative to the first metatarsal head reflects how much load and contact the crest (crista) of the head is experiencing. The crista is the ridge that the sesamoid articulates with, and chronic pressure from the sesamoid as it moves laterally with progression of deformity can wear it away. When the tibial sesamoid is in the most lateral position—beyond the articular margin of the first metatarsal head—the crest is subjected to ongoing contact, leading to erosion. In less advanced positions, the sesamoid remains under or at the edge of the head and the crista is typically preserved, so erosion is not evident.

The main idea is that how far the tibial sesamoid has translated relative to the first metatarsal head reflects how much load and contact the crest (crista) of the head is experiencing. The crista is the ridge that the sesamoid articulates with, and chronic pressure from the sesamoid as it moves laterally with progression of deformity can wear it away. When the tibial sesamoid is in the most lateral position—beyond the articular margin of the first metatarsal head—the crest is subjected to ongoing contact, leading to erosion. In less advanced positions, the sesamoid remains under or at the edge of the head and the crista is typically preserved, so erosion is not evident.