Hallux varus

Hallux varus
Other names	Sandal gap
	A right foot with hallux varus
Specialty	Orthopedic

Short description: Medial deviation of the great toe at the metatarsophalangeal joint

Hallux varus, also commonly referred to as sandal gap, is a clinical condition characterized by medial deviation of the great toe at the metatarsophalangeal joint.^[2] This condition, when acquired by adults, is usually caused by sports injury, surgical overcorrection of hallux valgus, or underlying causes such as arthritides.^[2]

A sandal gap that is congenital and not caused by an injury can be a normal variant, and can be visible on a pre-natal ultrasound as early as the second trimester. However, it is also considered to be a "soft sign" associated with an increased likelihood of a genetic abnormality, including Down's Syndrome,^[3] CLOVES syndrome, and at least forty other rare conditions.^[4] One 2011 study of the common morphological features in autistic children (sample size of n=421) found that 59% of the children in the study had a sandal gap, the most common morphological abnormality in the group.^[5]

Photos

Radiography of the left foot of a young male showing progressive hallux varus

References

↑ Weerakkody, Yuranga. "Sandal gap deformity - Radiology Reference Article - Radiopaedia.org". https://radiopaedia.org/articles/sandal-gap-deformity.
↑ ^2.0 ^2.1 Munir, Usama; Mabrouk, Ahmed; Morgan, Samer (2023), "Hallux Varus", StatPearls (Treasure Island (FL): StatPearls Publishing), PMID 29261893, https://www.ncbi.nlm.nih.gov/books/NBK470261/, retrieved 2023-10-17
↑ Smith-Bindman, R.; Hosmer, W.; Feldstein, V. A.; Deeks, J. J.; Goldberg, J. D. (Feb 28, 2001). "Second-trimester ultrasound to detect fetuses with Down syndrome: a meta-analysis". JAMA 285 (8): 1044–1055. doi:10.1001/jama.285.8.1044. PMID 11209176.
↑ "Sandal gap deformity". https://radiopaedia.org/articles/sandal-gap-deformity?lang=us.
↑ Ozgen, Heval; Hellemann, Gerhard S.; Stellato, Rebecca K.; Lahuis, Bertine; Van Daalen, Emma; Staal, Wouter G.; Rozendal, Marije; Hennekam, Raoul C. et al. (Jan 2011). "Morphological features in children with autism spectrum disorders: a matched case-control study". Journal of Autism and Developmental Disorders 41: 23–31. doi:10.1007/s10803-010-1018-7. PMID 20473590.