- Discussion:
- loss of normal medial longitudinal arch leads to pes planus, which can be flexible or rigid;
- may arise as a consequence of
hyper-pronation or from increased eversion of the subtalar joint;
- hence, the calcaneus lies in valgus and external rotation relative to the talus;
- associated midfoot sag may be due dorsal subluxation of the navicular on the talus;
- talonavicular subluxation throughout stance phase is a major biomechanical consequence of the flat foot deformity;
- the lateral column is short in relation to the medial column;
-
pediatric population:
- typically infants have a minimal arch and often toddlers have flattening of the long arch, forefoot pronation, & heel valgus
on wt bearing, severity of which is variable (this is especially common in black children);
- ligamentous laxity is apparent, & degree of abnormality in bone-ligament complex probably is determined genetically;
- usually within the first decade, these children spontaneously develop a strong noraml arch;
- references:
- The longitudinal arch. A survey of eight hundred and eighty-two feet in normal children and adults.
Staheli L, Chew D, Corbett M: J Bone Joint Surg 1987;69A:426-428.
-
adult population:
- may occur in 20 % of adults, most of which are flexible;
- many people w/ flat foot can walk as comfortably and as easily as others who w/ normal arches as long as there is no
heel cord contracture;
- flat feet w/ a concomitant heel cord contracture may limit function;
- there is some evidence that flat feet protect against
metatarsal stress frx, but are poor shock absorbers
with regard to the lower back (causing higher incidence of low back pain);
- in contrast, a cavus foot may actually be somewhat protective of stress related low back pain;
- etiology / cause of adult flat foot:
-
posterior tibial tendon rupture
- deficiency of the spring ligament complex:
-
Morphometric Dimensions of the Calcaneonavicular (Spring) Ligament
- references:
- The longitudinal arch. A survey of eight hundred and eighty-two feet in normal children and adults. Staheli L, Chew D, Corbett M: JBJS 1987;69A:426-428.
- Does arch height affect impact loading at the lower back level in running? M. Ogon MD. Foot and Ankle International. Vol 20. No 4. Apr 1999. p 265.
-
how the subtalar joint affects flat feet:
-
associated conditions / diff dx:
- Clinical Manifestations:
- must distinguish betwen flexible flat foot & rigid / spastic flat foot;
-
hypermobile foot:
- the suspended foot will regain a normal appearing arch;
- as the patient stands on his toes, the arch will reappear & heel will move out of a valgus position.
- this is a good indirect test for nl subtalar motion;
-
forefoot varus:
- once foot is placed in sub-talar neutral position assess whether there is relative forefoot varus (see exam of
subtalar joint);
- lateral impingement (sinus tarsi and fibular-calcaneal):
- ref:
Talocalcaneal and Subfibular Impingement in Symptomatic Flatfoot in Adults.
-
complicating factors:
-
heel cord contracture:
- lateral deviation of achilles w/ wt bearing;
- severe achilles contracture is associated with midfoot break down;
-
hyperpronation of hindfoot:
- supination of the forefoot which does not correct when hindfoot is reduced;
- everted heel w/ fails to invert w/ toe raise;
- abducted forefoot;
- Radiographic Analysis:
-
standing lateral:
- normally there is a straight line relationship between talus & first metatarsal;
- in flat foot this relationship will be lost & there will be a sag at either the talonavicular or naviculocuneiform joint;
-
standing AP:
- degree of heel valgus is important to assess;
- talocalcaneal angle is measured and if > 35 deg, heel valgus is said to be present;
- note the degree of talo-navicular uncoverage / subluxation;
-
oblique views to r/o tarsal colatition;
- references:
- Measurements on radiographs of the foot in normal infants and children.
J Bone Joint Surg 1988;70A;411. Vanderwilde R, Staheli LT, Chew DE:
- Non Operative Treatment:
- flexible flatfoot is generally a benign condition that rarely requires treatment;
- heel cord stretching should be the main emphasis of treatment;
- be sure to supinate the foot while stretching inorder to "lock the midfoot" (avoids worsening midfoot collapse);
-
foot orthotics:
- in most cases orthotics will not alter osseous relationships and are ineffective in may patients;
- furthermore, arch supports may actually make the patient's symptoms worse, until a concomitant heel cord contracture is relieved;
- in patients with talonavicular subluxation, consider taking a wt bearing AP of the patients feet with and without the inserts;
- if the talonavicular joint subluxation is not corrected w/ inserts then the inserts are probably not doing their job;
- in some cases, patients with a calcaneovalgus deformity can "normalize their wt bearing pattern" w/ a medial heel wedge;
- children and adolescents:
- many feet improve as the child ages, at least until 5 to 6 yrs old;
- flexible flatfeet are asymmetic for most pts, & its impossible to predict which planovalgus feet will become painful in adulthood;
- hence, most orthopaedists consider their use to be unnecessary in children;
- references:
- Corrective shoes and inserts as treatment for flexible flatfeet in infants and children.
Wenger D, Mauldin D, Speck G, et al: J Bone Joint Surg 1989; 71A: p 800-810.
-
The influence of footwear on the prevalence of flat foot. A survey of 2300 children.
-
The injury risk associated with pes planus in athletes.
-
A Randomized Controlled Trial of Two Types of In-Shoe Orthoses in Children with Flexible Excess Pronation of the Feet
- Indications for Surgery:
-
cerebral palsy:
-
equino-valgus foot deformities w/ heel cord contracture in patients w/ CP
will generally tend to have break down of mid-foot and longitudinal arch;
- these patients are best treated w/ tendo-achilles lengthening (w/ severe
contracture) or a
sub-talar fusion before mid-foot break down occurs;
- once mid-foot break down occurs, a
triple arthrodesis is required;
-
painful rigid flatfoot:
- small number of flexible flatfeet do not correct w/ growth & will become rigid due to adaptive changes occur;
- painful rigid flat foot will require
triple arthrodesis
-
painful flexible flatfoot:
- in this situation, it is important to determine the anatomic cause of the pain;
- as noted by JTC Lau and TR Daniels, a tarsal tunnel release w/ a concomitant pes planus may have the effect
of increasing posterior tibial nerve tension, which may explain the high rate of poor surgical results;
- in the same study, distraction calcaneo-cuboid arthrodesis reduced nerve tension;
- reference:
- Effects of tarsal tunnel release and stabilization procedures on tibial nerve tension in a surgically created pes planus foot.
JTC Lau and TR Daniels. Foot and Ankle Internation. Vol 19. No 11. Nov 1998. p 770.
- Contra-Indications for Surgery:
- hyper-mobile joints (such as w/
Marfan's,
Ehler's Danlos,
Down's);
- in adults, if feet are asymptomatic, surgery is almost never indicated;
- Operative Treatment:
- medial os calcis sliding osteotomy or opening wedge osteotomy of lateral calcaneus may realign hindfoot & relieve
symptoms w/o producing loss of motion associated w/ fusions;
-
FDL Transfer: (in the case of
PT rupture);
-
medial calcaneal sliding osteotomy:
-
lateral column lengthening:
- references:
- Effect of variation in calcaneocuboid fusion technique on kinematics of the normal hindfoot. A. Sands et al. FAI Vol 19. No 1. Jan 1998. p 19.
- Selective tarsal arthrodesis: An in vitro analysis of the effect on foot motion. H Gellman et al. Foot and Ankle. Vol 8. 1987. p 127-133.
- Calcaneo-valgus deformity. D. Evans. JBJS. Vol 57-B. 1975. p 270-278.
-
Early Graft Failure in Lateral Column Lengthening.
-
Evans calcaneal lengthening procedure for spastic flexible flatfoot in 32 patients (46 feet) with a followup of 3 to 9 years.
-
A Comparison of Lateral Column Lengthening and Medial Translational Osteotomy of the Calcaneus for Recon of Adult Acquired Flatfoot
-
medial cuneiform osteotomy:
- may be indicated w/ fixed forefoot supination;
-
medial soft tissue reconstruction:
- drill holes are made in the medial malleolus and the medial cuneiform thru which is passed a
free tendon graft (using the extensor digitorum longus tendon);
- ref: Reconstruction operations for acquired flatfoot: biomechanical evaluation.
HB Kitaoka MD et al. Foot and Ankle International. Vol 19. No 4. Apr 1998 p 203.
-
achilles tendon lengthening:
- may be indicated for intractable
equinus deformity, when other reconstructive procedures are to be performed as well;
-
triple arthrodesis:
- indicated only when there is severe midfoot collapse;
Evaluation of hyperpronation and pes planus in adults.
Acquired flatfoot in adults.
Reconstruction with tenodesis in an adult flatfoot model. A biomechanical evaluation of four methods.
Calcaneal lengthening for valgus deformity of the hindfoot. Results in children who had severe, symptomatic flatfoot and skewfoot.
Dynamic support of the human longitudinal arch. A biomechanical evaluation.
The relationship of pes planus and calcaneal spur to plantar heel pain
The longitudinal arch. A survey of eight hundred and eighty-two feet in normal children and adults.
Staheli L, Chew D, Corbett M: J Bone Joint Surg 1987;69A:426-428.
The mechanics of the foot: II. The plantar aponeurosis and the arch.
J Anat 1954;88:25. Hicks JH:
Calcaneal Lengthening for Valgus Deformity of the Hindfoot. Results in Children Who Had Severe, Symptomatic FlatFoot andSkew Foot.
Mosca V. JBJS (AM) Vol. 77-A, No 4, Apr 1995. p 500-512.
Two reconstructive techniques for flatfoot deformity comparing contact characteristics of the hindfoot joints.
AP McCormack MD et al. Foot and Ankle International. Vol 19. No 7. July 1998. p 452.
Isolated Medial Column Stabilization Improves Alignment in Adult-acquired Flatfoot.
Double arthrodesis in the adult.
