. 2015 Jun 30;9(6):29–43. doi: 10.3941/jrcr.v9i6.2142

Table 1.

Overview of radiographic parameters utilized in the interpretation of the hallux abductovalgus deformity and procedures used for their correction.

	Definition	Interpretation	Surgical Treatment
First Intermetatarsal Angle (1^st IMA)	Resultant angle created between the longitudinal bisections of the first and second metatarsals.	Normal range: 0–8 degrees Mild increase: 9–11 degrees Moderate increase: 12–15 degrees Severe increase: >15 degrees	Any translational metatarsal osteotomy will correct the 1^st IMA. Mild increases are typically addressed with a first metatarsal “head” procedure (i.e. the Austin/Chevron osteotomy). Moderate increases are typically addressed with a first metatarsal “shaft” procedure (i.e. the Scarf osteotomy). Severe increases are typically addressed with first metatarsal “base” procedure (i.e. the closing base wedge osteotomy or the Lapidus arthrodesis).
Hallux Abductus Angle (HAA)	Resultant angle between the longitudinal bisections of the hallux proximal phalanx and first metatarsal.	Normal range: 0–15 degrees Increases with progressive HAV deformity	Any procedure which directly decreases the 1^st IMA will also indirectly decrease the HAA. Several procedures that will directly decrease the HAA include the proximal phalanx Akin procedures and the first metatarsal-phalangeal joint arthrodesis procedure.
Metatarsal-sesamoid position (MSP)	Relationship between the tibial sesamoid and the longitudinal bisection of the first metatarsal	Normal position: 0–2 Defined on a 7 point scale (see Figure 2)	Any procedure which directly decreases the 1^st IMA will also directly decrease the MSP.
Proximal Articular Set Angle (PASA)	Relationship between the longitudinal axis of the first metatarsal and the articular cartilage on the first metatarsal head.	Normal range: 0–8 degrees Normally evaluated intra- operatively as opposed to radiographically.	The PASA may be directly decreased with the Reverdin first metatarsal head procedures.