Windlass Mechanism Research Articles

Traumatic rupture of plantar fascia leading to later development of claw toe deformity: two case reports

We report on two patients who had stubbing injury to a lesser toe causing soft-tissue bruising at the base of the toe without displacement on X-ray initially. Claw toe deformity of these toes developed some months later. Hicks' test showed that the cable windlass mechanism of the plantar fascia-plantar plate to these toes was not functioning. This indicates that the initial injury either damaged the cable, which is the plantar fascia attached to these toes, or tore its fibres, which later allowed the fascia to stretch and the metatarsophalangeal joint to sublux dorsally. Alternatively, the cable may gradually have slid off its pulley, the metatarsal head, as a result of tearing and later stretching of fibres in the plantar plate of the metatarsophalangeal joint. This plantar plate normally holds the slips of the plantar fascia underneath the metatarsal head. These mechanisms for the gradual development of claw toes are well recognized in rheumatoid disease and with hallux valgus. However, they have not been reported previously after a single episode of trauma.

Biomechanics of the first ray. Part II: Metatarsus primus varus as a cause of hypermobility. A three-dimensional kinematic analysis in a cadaver model

Variation in functional stability of the first metatarsocuneiform joint was analyzed between transverse plane deviated (adducted) and corrected first metatarsal positions in a closed kinetic chain model. Six fresh frozen cadaver specimens with intact ankles and feet were fitted with a custom fabricated titanium metatarsal jig, which allowed for manipulation of the first metatarsal in the transverse plane. Specimens were mounted into a custom-made acrylic load frame and axially loaded to 400 N. Radiowave three-dimensional tracking transducers were attached to the following osseous segments: first metatarsal head and base, medial cuneiform, and second metatarsal. A dorsally directed load was applied to the first metatarsal segment and resultant movements were measured. Repeated testing was performed on a transverse deviated and corrected first metatarsal positions with the hallux plantargrade and maximally dorsiflexed to engage the windlass mechanism. With the windlass mechanism engaged and first metatarsal corrected, a 26% increase in first ray plantarflexion occurred from a deviated to a corrected first metatarsal position (p < or = .05). This suggests that the windlass mechanism is more efficient when the first metatarsal, sesamoid apparatus, and hallux position are properly aligned with the orientation of the plantar aponeurosis. Clinically, this may explain the correlation of first ray hypermobility with the progression of bunion severity. Our study validates the earlier work of Hicks and adds additional insight into the functional stability in the medial column of the foot.

The windlass mechanism of the foot. A mechanical model to explain pathology.

This article presents a mechanical model that can be used to understand the foot, to help develop methods of treatment of foot pathology, and to provide direction for future research in foot mechanics and pathology. The anatomy and mechanical function of the windlass mechanism of the foot are analyzed using principles of mechanical engineering. The principles of force couples and free-body diagrams are explained and then applied to the foot. The relationship of the windlass mechanism to plantar fasciitis or heel spur syndrome, hallux abducto valgus, and hallux limitus is discussed.

Function of the plantar fascia

The plantar fascia has long been considered to have a significant purpose in the weightbearing foot, both in static stance and in dynamic function. Various functional and structural roles have been indicated by virtue of its anatomical attachments. This paper aims to review the anatomy and biomechanical considerations of the plantar fascia and, in particular, its central component known as the plantar aponeurosis. Static and dynamic roles of the plantar aponeurosis will be discussed with emphasis placed on the dynamic ‘windlass mechanism’ phenomenon exhibited on first metatarsophalangeal joint dorsiflexion, leading to further indications for research on its role in plantar fascial injury and the pronated or pes planus foot.

The windlass mechanism during normal walking and passive first metatarsalphalangeal joint extension

Objective. To assess the relationship between passive first metatarsophalangeal extension and rearfoot motion during walking on the windlass mechanism. Design. An in vivo study of the windlass mechanism during passive extension of the first metatarsophalangeal joint and walking. Background. Despite theoretical work regarding the windlass mechanism in cadavers, there is little research concerning its in vivo role. Methods. The amount of first metatarsophalangeal extension and medial longitudinal arch movement of the right foot in 20 subjects between the age of 22 and 55 years was recorded as they sat with their right hip, knee and ankle in 90 ° and their great toe passively extended. In addition, movement of the rearfoot was recorded while they walked. Results. The results of this study showed that the windlass mechanism is active during passive extension of the great toe. In addition, subjects could be divided into two groups ( immediate and delayed) based upon the timing of when the windlass mechanism began relative to passive extension of their first metatarsophalangeal joint. During walking, the delayed group was more inverted at heel strike and had a greater magnitude of rearfoot eversion. Conclusions. Two distinct subpopulations of individuals can be identified by when the windlass mechanism is initiated relative to passive first metatarsalphalangeal extension.