E-Journal

1st Ray Position and 1st MPJ Motion                                                                             Issue No. 43

The process leading to development of hallux abducto valgus and hallux rigidus has been debated for many years. This article focused on the relationship between 1st ray position and 1st metatarsophalangeal joint (MPJ) motion.

 

Sincerely,
 

Cherri Choate, DPM
Larry Huppin, DPM
Alona Kashanian, DPM
Paul R. Scherer, DPM 
Position of the First Ray and Motion of the First Metatarsophalangeal Joint

The purpose of this study was to determine how a more dorsiflexed position of the 1st ray will affect the range of motion of the 1st MPJ in static stance.

 

Methods

  • 10 males (20 feet) 
  • Inclusion criteria included normal amounts of nonweightbearing motion in ankle, subtalar and midtarsal joints, 1st ray and 1st MPJ
  • 1st MPJ dorsiflexion was measured in:
    • Relaxed stance
    • Relaxed stance with 1st ray dorsiflexed by 4 mm
    • Relaxed stance with 1st ray dorsiflexed by 8 mm
  • Goniometer was used to measure closed kinetic chain dorsiflexion of 1st MPJ motion in each of three above situations

 Results

  • 1st MPJ doriflexion was decreased by 19% with 1st ray dorsiflexed by 4 mm
  • 1st MPJ dorsiflexion was decreased by 34.7% with the 1st ray dorsiflexed by 8 mm 
Significance of the Article

The position of the first ray has significant influence on the 1st MPJ range of motion static stance. As a result, any structural or functional deformity that leads to a dorsiflexed position of the 1st ray will likely lead to decreased dorsiflexion of the 1st MPJ. This decreased motion of the 1st MPJ, termed functional hallux limitus, will lead to development of pathology at the 1st MPJ: hallux abducto valgus or hallux rigidus. The authors hypothesized that the pathway that leads to pathology development is related to the amount of 1st ray range of motion available during gait.

Significance for Orthotic Therapy

Certain orthotic modifications can be used to encourage a more plantarflexed position of the 1st ray. The most commonly used modification is the reverse Morton's extension as it allows the 1st metatarsal head, which represents the 1st ray, to drop into a more plantarflexed position. Another option would be ordering a minimal fill as this would lead to a more plantarflexed position of the 1st ray within the shell itself. In addition, modifications which would discourage rearfoot eversion, which leads to dorsiflexion of the 1st ray, would be helpful. These "anti-eversion" modifications include: medial heel skive, wide plate, and deep heel cup.

References