- Discussion:
- cavus deformity of the foot (elevated longitudinal arch) due to fixed plantar flexion of the forefoot;
- main type is the
cavovarus and less frequent is the
cavovarus;
- associated with spinal cerebellar degenerative dz;
-
associated deformities:
-
claw toes
-
differential dx: (commonly associatted with neurologic disorders)
- asymmetric or unilateral deformity:
-
cerebral palsy
- diastematomyelia (spinal cord dysraphism look for scoliosis)
-
spinal cord tumor
-
tethered cord
- symmetric or bilateral deformity:
-
becker muscular dystrophy
-
cerebral palsy
- congenital pes cavus
-
charcot marie tooth;
- Dystonia musculorum deformans (equinovarus)
-
friedreich's ataxia
-
poliomyelitis
- idiopathic;
- Exam:
-
subtalar joint;
- in pes cavus, the upward axis is increased (normal 42 deg) and therefore the subtalar joint allows less inversion
and eversion (more internal and external rotation);
- because the longitudinal axis is closer to the mid-line (less than the normal 16 to 23 deg), less than normal dorsiflexion
and plantarflexion occurs at this joint;
-
lateral block test (Coleman) assesses hindfoot flexibility of cavovarus foot (flexible feet correct to normal);
- foot is evaluated clinically for muscle strength and for flexibility, especially of the hindfoot varus;
- the deformity is progressive, and rigidity increases over time;
- evaluate for scoliosis and get thorogh
neuro exam;
- Radiographs:
- angle subtended by line drawn through the axis of the talus & first metatarsal (normal = 0 degrees);
- Work Up:
- Family history
-
Neuro Exam
- X-rays of entire spine
-
EMG and nerve conduction studies
- MRI
myelogram
- Treatment of Early Deformity:
- treatment involves soft-tissue releases and/or tendon transfers;
- any proposed osseous procedures must not affect growth of the foot, such as calcaneal and/or metatarsal osteotomies;
-
planter release:
- indicated for patients less than 10 years of age w/ cavus deformity w/ significant plantar flexion of first ray;
-
plantar medial release:
- indicated for rigid hindfoot w/ fixed varus angulation;
- involves
planter release along w/ medial tarsal structures;
- released medial structures include talonavicular joint capsule, superficial deltoid ligament, and possibly the long toe flexors;
-
tendon transfers:
- indicated for patients w/ a supple inversion deformity w/ weak evertors;
- a prerequisite for this procedure is a plantagrade foot which is achieved w/
planter release;
- consider lateral transfer of
tibialis anterior tendon into the mid-tarsal region along the long axis of third ray;
- Rigid Deformity:
- fixed bony deformity is better managed by a combination of calcaneal and metatarsal osteotomies and may require the use of AFO's;
-
calcaneal osteotomy:
- for correction of hindfoot varus deformity & mid-tarsal osteotomy for
correction of midfoot cavus and varus deformity have been useful;
- calcaneal osteotomy does not impede growth since it is not made thru cartilage growth surface;
- posterior displacement calcaneal osteotomy is effective in correcting calcaneocavus deformity of the type II neuropathy;
- in young patients w/ w/ milder deformity, translate the distal and posterior calcaneal fragment laterally
w/o removal of an osseous wedge;
- lateral slide osteotomy is cut slightly obliquely, passing from superior position on lateral surface
to a more inferior position on the medial surface;
- distal fragment can be translated laterally as much as 1/3 of its transverse diameter, thus allowing
for conversion of wt-bearing from a varus to a slight valgus position;
- w/ severe deformity consider:
triple arthrodesis;
Assessment and management of pes cavus in Charcot-Marie-tooth disease.
Cavus deformity of the foot after fracture of the tibial shaft.
