Comparison of dorsal and dorsomedial displacement in evaluation of first ray hypermobility in feet with and without hallux valgus.
BACKGROUND
Hypermobility of the first ray, a probable primary cause of hallux valgus, has traditionally been evaluated in the dorsal direction only although the first tarso-metatarsal joint allows movement in a dorso-medial direction.


METHODS
600 feet, divided according to the presence or absence of hallux valgus, were evaluated for both dorsal and dorso-medial displacement using a Klaue device.


RESULTS
In the control group, the mean first ray displacement was 7.2mm (4.2-11.3) in the dorsal direction (sagittal plane) and 8.3mm (4.0-12.6) in the 45° dorso-medial direction. In the hallux valgus group, the mean first ray mobility was 9.8mm (5.2-14.1) in the dorsal direction compared to a mean of 11.0mm (5.9-16.2) in the 45° dorso-medial direction.


CONCLUSIONS
It is a paradox that hypermobility of the first ray is measured in only a dorsal (vertical) direction whereas a hallux valgus angle and an intermetatarsal angle are only measured in a transverse plane. Furthermore, the weightbearing foot pronates during gait and the first metatarsal is displaced in a dorsomedial direction rather than a pure dorsal direction. It is suggested that measurement hypermobility of the first ray at a 45° dorso-medial direction is more appropriate.
Royal National Orthopaedic Hospital, Stanmore, Middelesex HA7 4LP, United Kingdom. Electronic address: dishansingh@aol.com.
Dishan
D
Singh
Orthopaedic Clinic, Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padua, via Giustiniani 2, 35128 Padova, Italy. Electronic address: carlo.biz@unipd.it.
Carlo
C
Biz
Orthopaedic Clinic, Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padua, via Giustiniani 2, 35128 Padova, Italy. Electronic address: marcocorradin@yahoo.it.
Marco
M
Corradin
Orthopaedic Clinic, Department of Surgery, Oncology and Gastroenterology DiSCOG, University of Padua, via Giustiniani 2, 35128 Padova, Italy. Electronic address: favero11@libero.it.
Laura
L
Favero
D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006215:Hallux Valgus / Q000150:complications / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007593:Joint Instability / Q000150:complications / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008683:Metatarsophalangeal Joint / Q000503:physiopathology*; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
Hallux valgus; Hypermobility first ray; Lapidus; Ligamentous laxity