Background Fluid resuscitation may be detrimental when given before bleeding

Mobility of the first-ray is associated with several common lower extremity disorders. However, the reliability and validity of clinical measurement remains unclear. In this study we examined first-ray mobility by using one hand to stabilize the lesser metatarsals while the clinician's other hand applied a displacement force to the head of the first metatarsal. The amount of mobility was graded as stiff, normal or hypermobile. We then used a well-validated mechanical device to perform similar tests and assessed validity, intrarater reliability and interrater reliability. Three clinicians having varied levels of experience graded first-ray mobility on 15 subjects. A separate investigator measured dorsal mobility with a mechanical device. Both methods of testing were repeated to assess measurement reliability. Reliability was estimated by kappa (K) statistics. Spearman correlation assessed the relationship between mobility graded manually and dorsal mobility measured by device. Manual examination intrarater K values ranged from 0.50 to 0.85, and interrater agreement from 0.09 to 0.16. Manual grading was not related (r = -0.21) to the absolute measure of total dorsal mobility made by device. This brings into question the validity and reliability of manual estimates of first-ray mobility.

The hypermobile first ray has been implicated as contributing to the cause and progression of hallux valgus deformity. Deformity of the hallux is often accompanied by an enlarged first intermetatarsal (IM 1-2) angle. It has been hypothesized that subjects having an abnormally large IM 1-2 angle have laxity of the first ray. Objectives of this study were to compare dorsal mobility of the first ray in subjects with hallux valgus to asymptomatic controls, and to investigate the relationship between dorsal mobility and the IM 1-2 angle. Fourteen subjects (age 23-81) with hallux valgus were matched by gender and age to control subjects. The IM 1-2 angle was measured from radiographs. A load-cell device measured dorsal mobility of the first ray under a standard load of 55 N. Pearson's correlation coefficient identified a marginal correlation (r = .51) between IM 1-2 angle and dorsal mobility. An independent t-test showed a statistically (P < 0.01) larger amount of dorsal mobility in the group of subjects having hallux valgus. Mobility of the first ray was increased in subjects with hallux valgus and a large IM 1-2 angle may be an indicator of increased dorsal mobility.

The relationship between a static measure of dorsal first ray mobility and dynamic motion of the first ray, midfoot, and hindfoot during the stance phase of walking was investigated in healthy, asymptomatic subjects who represented the spectrum of static flexibility. Static first ray mobility of 15 subjects was measured by a load cell device and ranged from stiff (3.1 mm) to lax (8.0 mm). Using three-dimensional motion analysis, mean first ray dorsiflexion/eversion and mid-/hindfoot eversion peak motion, time-to-peak, and eversion excursion were evaluated. Subjects with greater static dorsal mobility of the first ray demonstrated significantly greater time-to-peak hindfoot eversion and eversion excursion (p <.01), and midfoot peak eversion and eversion excursion (p <.01). No significant association was found between static first ray mobility and first ray motion during gait. This research provides evidence that the dynamic response of the foot may modulate the consequences of first ray mobility and that compensory strategies are most effective when static measures of dorsal mobility are most extreme.

Previous designs for a device to measure first ray mobility have included compression of the first metatarsal fat pad as part of the measurement of displacement or have failed to standardize the force applied to the head of the first metatarsal. In this investigation, assessment of vertical mobility of the first ray of both feet in 14 volunteers was determined using a device that applied dorsiflexing force to the first metatarsal. First ray displacement was measured initially from the plantar surface and then from the dorsal aspect of the head of the first metatarsal. The difference between plantar- and dorsal-surface-measured vertical displacement was highly significant. This study suggests that mobility of the first ray measured from the dorsal aspect of the first metatarsal head eliminated compression of the plantar fat pad from being interpreted as part of the measurement of displacement.