Is the Planus Foot Type Associated With First Ray Hypermobility?

Area of Science:

• Biomechanics
• Podiatry
• Orthopedics

Background:

• Foot type is often linked to various foot pathologies.
• The relationship between first ray hypermobility and foot type requires further investigation.
• Understanding this association is crucial for diagnosing and managing foot conditions.

Purpose of the Study:

• To investigate first ray hypermobility in individuals with planus and rectus foot types.
• To determine the influence of first ray hypermobility on static foot structure measurements.
• To explore the relationship between foot type and first ray mobility.

Main Methods:

• Twenty asymptomatic participants with planus (n=23) and rectus (n=17) foot types were assessed.
• Static foot structure parameters including arch height index, arch height flexibility, and first metatarsophalangeal joint flexibility were measured.
• First ray mobility was measured, with ≥8 mm defining "first ray hypermobility".

Main Results:

• 86% of participants with first ray hypermobility had a planus foot type.
• No significant differences were found in arch height flexibility or first metatarsophalangeal joint flexibility between groups.
• Weightbearing first ray mobility and first metatarsophalangeal joint laxity predicted partial weightbearing first ray mobility (38% variance).

Conclusions:

• A significant association exists between planus foot type and first ray hypermobility.
• Weightbearing first ray mobility and first metatarsophalangeal joint laxity are predictive of partial weightbearing first ray mobility.
• These findings suggest an interaction between the translational and rotational mechanics of the first ray.