The distal metatarsal articular angle (DMAA) evaluates the relationship between the longitudinal axis and the articular surface of the first metatarsophalangeal joint and thus metatarsophalangeal coverage or joint congruity on a weight-bearing dorsoplantar radiograph of the foot.
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Usage
The distal metatarsal articular angle is used for operative planning in the setting of hallux valgus with respect to the operative technique such as a double osteotomy 1-4.
Measurement
The angle between the perpendicular of the longitudinal axis and a parallel line to the distal articular surface of the first metatarsal bone is obtained with the apex laterally 1,2.
Interpretation
A distal metatarsal articular angle <10° is considered normal 1,2. Measurement is difficult with a high inter and intra-observer variability 2.