A comparison of trial shoe and shell shoe fitting techniques

1995 academic paper by R.C-C. Chen and M. Lord, published in Prosthetics and Orthotics International, volume 19

Notes

• UK orthopedic:
  • made to measure or from casts
  • trial shoes
  • rough finishing stage shoes
  • uppers tacked in place
  • temporary soles
• continental Europe
  • shell shoe
  • vacuum molded PVC over the last

  • Because the shoe last shape is adjusted before patterns and shoe uppers are cut, more complex styles can be attempted with confidence.

• basic lack of quantification of what constitutes a good fit

• trend towards more quantitative descriptions needed for computer aided design systems

• factors
  • shoe related
    • last shape
    • shoe construction
  • subject related
    • flexibility of foot
    • preference for tightness
    • pathology
    • different and unfamiliar feel of shell shoes

• of its nature subjective

• extensive fit assessments in “volume trade”

• Therefore considerable experience resides in the fitting departments at shoe manufacturing companies (as opposed to the limited skill in shoe shops). [???]

• The protocol described below was derived from the fit assessment procedure used at C & J Clark International, Street, Somerset, UK. The method is also compatible with the British Standard 5943 (1980) Methods for Measurement and Recording for Orthopaedic Footwear.

• partial weight bearing: seated, shin vertical leg weight on foot
• forepart
  • length allowance

    • the standard of around 8 mm for fashion shoes, or up to 15 mm for orthopaedic shoes

    • may exclude the end part in pointed or shallow toe boxes

  • forepart width across joint
  • no excessive pressure or empty space to sides

  • the joint of the foot should be aligned from the medial side to the widest part of the shoe

• midfoot
  • record facing gap or overlap
• quarters

  • any pressure on the medial and lateral malleoli

  • must be clear of the topline

• backpart

  • If the heel can be rocked in the shoe, the seat may be too wide — if the foot is too wide for the seat, it will tend to flatten the sides and cause gaping at the topline under the ankle.

  • heel grip assessed during walking
• five-point scale
  • UA too tight/small
  • AO adequate: on the tight/small side
  • OK good fit
  • AO+ adequate; on the loose/large side
  • UA+ too loose/large
• shell shoe making
  • transparent material
  • fairly stiff 500 µ PVC for the heel area and side walls
  • more flexible 200 µ PVC over the top of the vamp
  • last mounted bottom up in vacuum machine
  • insole already in place
  • cut small v notches into side wall to help flex at MP joints
  • last turned over, softer PVC on top

  • The top line of the uppers was trimmed consistently according to a set of geometric construction rules used by Dutch orthopaedic shoe-makers, which results in standardised backseam height, under-ankle height and vamp point…

  • vamp split to allow foot in
  • small holes to form mock lace panel
• trial protocol
  • four styles of Clarks
  • asymptomatic female subjects
  • assessments by senior fitter at Clarks
• results
  • most subjects reported shell shoes slightly bigger
  • shell shoes: white patches of skin seen

  • the outcome of the two methods is very similar

  • Only in the region of the heel were there any differences of note.

  • it is normal practice to apply a ‘heel clip’, or removal of material, to the shoe upper patterns at the topline in the region of the heel backseam so that an adequate heel grip is obtained. A shell shoe obviously cannot incorporate this feature. [???]

  • machine lasting a shoe, the shoe shrinks a bit after taking out the last
  • different sensations from different materials
  • there are other materials for shells, but they’re not transparent
  • would help to define how much pressure causes whitening of skin versus tolerable pressure
  • might be different with pathologies

  • it would appear that of the shoe related fit factors, the construction factors are secondary to the last shape in determining initial fit

  • fitting with shell shoes needs little modification to the orthotist’s technique

  • gave the same result

  • the only compensation needed in interpretation of the fit is in the area of the heel grip