- See:
Orthotics for the Foot:
- Plantar Keratosis:
- this callus is a circumscribed keratotic area which may or may not be associated with a hammered great toe;
- kerkatosis often resembles
verruca plantaris, for which it is mistakenly treated until the
keratosis breaks down and ulcerates or leaves a permanent scar;
- although keratosis under the first metatarsal head is common, it is more common to have disabling
symptoms under the middle three metatarsals;
-
callus under the first metatarsal:
- it is formed by the bearing of wt on the pointed area of a malformed or displaced tibial
sesamoid,
or occassionally, a fibular sesamoid;
- often associated w/
sesamoiditis and can be related to a sharp pointed sesamoid;
- in mild cases of callus under the first metatarsal head, proper redistribution of wt bearing
by means of a shoe inlay or Thomas bar relieves the lesion;
- in severe cases, excision of the plantar surface of the offending sesamoid or both are necessary;
- references:
- Tibial sesamoid shaving for treatment of intractable plantar keratosis.
RA Mann and KL Wapner.
Foot Ankle. Vol 13. 1992. p 196-198.
-
callus under the middle three metatarsals:
- callus under the middle metatarsals is secondary to a depressions of anterior arch and
is often accompanied by contracted or hammered toes (
claw toes);
- plantar surface of the head of each of the lesser metatarsals has two condylar projections,
these may end in sharp points;
- condylar projection on fibular side is always larger of two;
- middle three metatarsals form the dome of the anterior metatarsal arch, which functions as
a shock absorber and was meant to bear wt only briefly during each step;
- because modern foot wear buckles the MP joints, almost everyone has a depressed anterior arch;
- therefore, the palmar condyles of the metatarsals almost always bear full wt, and may gouge
the soft tissues underneath;
- skin underneath sharp condyles may be subject to fibrotic changes as protective measure;
- greater the accumulation of horny layers, the less space there is between the
condylar surface and contact area;
- further compression of soft tissues covering these areas occurs;
-
callus under the 5th metatarsal head:
- callus is generally result of faulty wt distribution of foot, which forces 5th metatarsal
to bear excessive amount of total body wt;
- sometimes the callus is caused by an unusually pointed plantar condyle of the metatarsal head;
- metatarsal inlay or a Thomas bar added to a properly fitted shoe corrects most mild cases;
- Treatment:
- w/ plantar corns, palliative measures such as reduciton of the horny accumulation and then
padding of the area to distribute pressure give relief in most cases;
- intractable conditions over a non wt bearing area respond to excision of the condylar prominence;
- calluses are basically caused by shoes w/ pointed toes, short toes, or both, that force the
toes to buckle and thus produce a hammar toe deformity at the MP joints;
Intractable plantar keratosis.
