what-when-how
In Depth Tutorials and Information
6
occurs during the gait cycle and the longer it persists into the propulsive
period, the more severe the wear over the anterior-medial aspect of the
second metatarsal head. If instability is caused solely by midtarsal joint
long axis supination, the wear will be almost entirely under the second
metatarsal head. The clawing of the toes is an attempt to use muscle
action to overcome the instability. This will increase the toe wear mark
but because of the abnormal position of the apices, the mark will move
more proximally. It should be noted that wear marks will only be present
on the shoes of a propulsive foot and in the case of a hyperpronated foot
there will be very little tread line wear.
Key
Concept
The 'hypermobility' referred to here relates to impaired functional
stabilization, and not to benign joint hypermobility syndrome (or other
connective tissue disorder) that causes generalized hypermobility.
Variation in tread line wear - mild functionally
hypermobile foot
A mildly hypermobile foot, often the result of fully compensated rearfoot
varus, produces only slight changes in treadline wear pattern with over-
load over the middle three metatarsals and possible overloading under
the interphalangeal joint of the first toe caused by hallux limitus.
Distortion and wear of the uppers
In the individual whose foot is functioning normally, there will be little wear
and distortion to the shoe upper other than a crease across the vamp
that coincides with the tread line and the MTP joints.
Many of the frequently occurring variations in bony alignment of the
foot result in function that impedes the normal plantarflexion of the first
ray. This should occur during the propulsive period of the gait cycle but
if it does not, is described as a functional hallux limitus since the hallux is
unable to dorsiflex during the propulsive phase. This problem is more
commonly associated with a fully compensated rearfoot varus. Addition-
ally, as a result of the jamming of the first MTP joint, hyperextension of
the terminal phalanx of the hallux occurs. The failure of dorsiflexion of the
joint will often result in an alteration in the angle of the crease across the
vamp of the shoe and the hyperextension of the toe may cause a visible
bulge in the upper.
In the pes cavus or varus type of foot, there is generally some degree
of supination contracture of the midtarsal oblique axis. This results in a
