AAOS Comprehensive Orthopaedic Review
Section 3 - Pediatrics
Chapter 33. Pediatric Conditions Affecting the Lower Extremity
I. Limb-Length Discrepancy
A. Epidemiology—Small (up to 2 cm) limb-length discrepancies (LLDs) are common, occurring in up to two thirds of the general population.
B. Secondary problems from LLD
1. The prevalence of back pain may be higher with large discrepancies (>2 cm), but the evidence is limited.
2. During double-limb stance, the hip on the long side is relatively less covered by the acetabulum. Osteoarthritis is seen more commonly (84% of the time) on the long-leg side.
3. LLD increases the incidence of structural scoliosis to the short side. In up to one third of cases, the scoliosis is in a noncompensatory direction.
1. Measure the discrepancy by placing blocks under the short leg to level the pelvis.
2. Hip, knee, and ankle contractures will affect the apparent limb length and must be ruled out. A hip adduction contracture causes an apparent shortening of the adducted side.
3. The advantages and disadvantages of various imaging techniques are listed in
4. Up to 6% of patients with LLD from hemihypertrophy develop embryonal cancers (eg, Wilms tumor). Routine abdominal ultrasounds are recommended until age 6 years.
D. Prediction methods
1. Rule of thumb method
a. Assumes growth ends at age 14 years for girls and 16 years for boys
b. Estimates the annual contribution to leg length of each physis near skeletal maturity (during the last 4 years of growth)
i. Proximal femoral physis—4 mm
ii. Distal femoral physis—10 mm
iii. Proximal tibial physis—6 mm
iv. Distal tibial physis—5 mm
2. Growth remaining method—LLD prediction based on Green and Anderson tables of extremity length for a given age.
[Table 1. Assessment of Limb-Length Discrepancy Using Imaging Techniques]
Table 2. Treatment Algorithm for Limb-Length Discrepancy]
3. Moseley straight line graph method
a. This method improves the accuracy of Green and Anderson prediction by reformatting the data in graph form.
b. It accounts for differences between skeletal age and chronologic age.
c. It minimizes errors of arithmetic or interpretation by averaging serial measurements.
4. Multiplier method
a. This method predicts final limb length by multiplying the current discrepancy by a sex- and age-specific factor. It is most accurate for discrepancies that are constantly proportional (eg, congenital).
b. Girls have one half of their final leg length at age 3 years and boys at 4 years.
1. There are many causes of LLD including congenital conditions, infection, paralytic conditions, tumors, trauma, and osteonecrosis.
a. In congenital conditions, the absolute discrepancy increases but the relative percentage remains constant (eg, a short limb that is 70% of the long side at birth will be 70% of the long side at maturity).
i. Average female leg length at maturity: 80 cm
ii. Average male leg length at maturity: 85 cm
b. Children with paralysis usually have shortening of the more severely affected side.
2. Static discrepancies (eg, a malunion of the femur in a shortened position) must be differentiated from progressive discrepancies (eg, physeal growth arrest).
1. Physeal bar excision
a. Physeal bars following trauma tend to be more discrete (and more amenable to excision) than are bars resulting from infection or ischemia.
b. Bridge resection is indicated if the bony bridge involves <50% of the physis in patients with at least 2 years of growth remaining.
2. Discrepancy correction (Table 2)
a. Nonsurgical—Any size discrepancy can be corrected with a shoe lift, but shoe lifts >5 cm are poorly tolerated because they are heavy and may result in subtalar and ankle inversion injuries.
i. General principles
(a) The surgical correction must address the anticipated final LLD, not just the current discrepancy.
(b) In paralytic conditions (such as myelodysplasia, cerebral palsy, or polio), it is often best to leave the LLD undercorrected to facilitate foot clearance of the weak leg. This is especially important if the patients walks with a brace that locks the knee in extension.
ii. Shortening techniques
(a) Epiphysiodesis is the treatment of choice for discrepancies of 2 to 5 cm because of the very low complication rate. If proximal tibial epiphysiodesis is performed, concomitant proximal fibular epiphysiodesis should also be performed if more than 2 to 3 years of growth remain (to prevent proximal fibular overgrowth and prominence).
(b) Acute osseous shortening is typically used for discrepancies of 2 to 5 cm after skeletal maturity.
(1) Fewer complications occur with femoral shortening than with tibial shortening.
(2) Shortening is best tolerated when limited to <5 cm.
iii. Lengthening techniques
(1) Uniplanar or multiplanar external fixation
(2) External fixation with intramedullary nail
(3) Intramedullary distraction
(1) Lengthen at metaphyseal level whenever possible.
(2) Delay the onset of distraction by 5 to 7 days after the corticotomy is performed.
(3) Lengthen at a rate of 1 mm/day (0.25 mm four times/day).
(4) Limit the lengthening goal to <20% of the individual bone length per lengthening period.
(a) Incomplete arrest or angular deformity can result from either open or percutaneous epiphysiodesis techniques.
(b) Common complications of lengthening include pin site infection, pin or wire failure, regenerate deformity or fracture, delayed union, premature cessation of lengthening, and joint subluxation/dislocation.
II. Angular Deformities
1. Normal physiologic knee alignment includes periods of "knock knees" and "bowed legs" (
2. Children with bowed legs after age 2 years may require further evaluation.
B. Blount disease (tibia vara)
a. The most common cause of pathologic genu varum is Blount disease.
b. Progressive tibia vara can occur in infants and adolescents (
Excess medial pressure (eg, heavy, early walkers who are in physiologic varus alignment) produces an osteochondrosis of the physis and adjacent epiphysis that can progress to a complete physeal bar.
[Figure 1. Graph illustrating the development of the tibiofemoral angle in children during growth, based on measurements from 1,480 examinations of 979 children. Of the lighter lines, the middle one represents the mean value at a given point in time, and the other two represent the deviation from the mean. The darker line represents the general trend.]
[Table 3. Infantile Versus Adolescent Blount Disease]
Figure 2. Assessment of the metaphyseal-diaphyseal (A) and tibial-femoral (B) angles.]
In adolescent Blount disease, a varus moment at the knee during the stance phase of gait inhibits medial physeal growth according to the Heuter-Volkmann principle.
a. Physiologic bowing versus Blount
b. Clinical findings suggestive of pathologic bowing
i. Proximal tibial location of bowing
ii. Sharply angular deformity
iii. Asymmetric bowing of the two legs
iv. Progressive deformity on serial examinations
v. Lateral thrust during gait
vi. Very severe deformity
(a) Children older than 18 months of age with clinical deformity >20°
(b) Less than 5th percentile for height, or a family history of metabolic bone disease
(c) Findings suggestive of pathologic bowing (as noted above)
ii. Because of internal tibial torsion, it is essential to obtain the radiographs with the patellae directed anteriorly.
iii. When the metaphyseal-diaphyseal (MD) angle (Figure 2) is <10°, there is 95% chance the bowing will resolve.
iv. If the MD angle is >16°, there is 95% chance of progression. For MD angles between 11° and 16°, there is considerable overlap between physiologic genu varum and Blount disease.
4. Classification—Langenskiold described six radiographic stages that can develop over 4 to 5 years.
a. Early changes include metaphyseal beaking and sloping.
b. Advanced changes include articular depression and medial physeal closure.
i. Bracing efficacy is controversial.
ii. Bracing is indicated only in patients 2 to 3 years of age with mild disease (stage 1 to 2).
iii. Poor results are associated with obesity and bilaterality.
iv. Improvement should occur within 1 year.
v. Bracing must be continued until the bony changes resolve, which usually takes 1.5 to 2 years.
i. General surgical principles
(a) To avoid undercorrection, the distal fragment is fixed in slight valgus, lateral translation, and external rotation.
(b) Performing an anterior compartment fasciotomy at the time of surgery decreases the postoperative risk of compartment syndrome.
(c) The mechanical axis can be confirmed intraoperatively by holding the bovie cord directly over the center of the femoral head and ankle. The cord should pass over the lateral tibial plateau.
ii. Infantile Blount disease
(a) Patients older than 3 years require proximal tibial valgus and rotational osteotomy.
Table 4. Common Causes of Genu Valgum]
(1) 1 or 2 pins and a cast provide fixation.
(2) Fibular osteotomy is needed to allow for sufficient correction.
(3) The risk of recurrence is much less if the surgery is performed before age 4 years.
(b) If a bony bar is present, a bar resection with interposition of methylmethacrylate (epiphysiolysis) is performed concomitantly.
(c) If significant depression of the medial tibial plateau exists, a medial tibial plateau elevation and realignment osteotomy may be necessary.
iii. Adolescent Blount disease
(a) Temporary or permanent epiphysiodesis prevents deformity progression and may allow some correction in adolescents with mild to moderate Blount in whom at least 15 to 18 months of growth remain.
(b) Severe deformities require proximal tibial osteotomy and occasionally a femoral osteotomy (if distal femoral varus exceeds 7° to 10°).
(c) Fixation is generally with a plate or external fixation.
C. Genu valgum
a. Typically, developing children aged 3 to 4 years have up to 20° of genu valgum.
b. Genu valgum should not increase after 7 years of age.
c. After age 7 years, valgus should not exceed 12° with an intermalleolar distance <8 cm.
Figure 3. Radiographs demonstrate hemiphyseal tethering with a plate-screw construct.]
a. The deformity is usually in the distal femur but may also arise in the proximal tibia.
b. The degree of deformity necessary to lead to degenerative changes in the knee is not known.
3. Causes (Table 4)
i. Bracing is unnecessary for physiologic valgus and often ineffective in pathologic valgus.
ii. Genu valgum following proximal tibial metaphyseal (Cozen) fractures almost universally spontaneously remodels and should be observed.
i. Indications—Correction is indicated if a line drawn from the center of the head of the femur to the center of the ankle falls in the outer quadrant of the tibial plateau (or beyond) in children older than 10 years.
(a) Hemiepiphysiodesis or temporary physeal tethering
(1) Tethering options include staples, screws across the physis, or newer plate/screw devices (Figure 3). The hardware must be placed extraperiosteally in order to avoid unintended physeal injury and growth arrest.
(2) Close follow-up is necessary to avoid overcorrection.
(3) Growth can resume with tether removal by 24 months.
(4) Nomograms are available to determine the timing for permanent hemiepiphysiodesis or the anticipated time to correction for temporary hemiepiphysiodesis.
(b) Osteotomies are necessary when insufficient growth remains or the site of the deformity is away from the physis.
5. Complications—To reduce the risk of peroneal injury with varus osteotomy, consider either gradual correction, preemptive peroneal nerve release, or a closing-wedge technique.
III. Rotational Deformities
1. Rotational profiles not only change during childhood, but they also vary widely among healthy children of the same age.
2. Femoral anteversion
i. Intoeing from femoral anteversion is most evident between 3 and 6 years of age.
ii. Anteversion is 30° to 40° at birth. It decreases to 15° by skeletal maturity.
iii. Anteversion occurs more commonly in girls than boys (2:1) and often is hereditary.
i. Rotation variations have not been directly correlated to degenerative changes of the hip or knee.
ii. Patellofemoral pain can arise with increasing femoral anteversion, but a pathologic threshold has not been identified.
(a) Brace-dependent ambulators (such as those with cerebral palsy or myelodysplasia) tolerate less tibial torsion because the compensatory gait mechanisms (knee and subtalar motion) are unavailable.
(b) Lever-arm dysfunction in children with neuromuscular disorders is the reason osteotomies are frequently indicated in such children. (See chapter 27, Neuromuscular Disorders.)
Figure 4. The thigh-foot axis is best measured with the child in the prone position.]
i. Intoeing gait with medially rotated patellae is indicative of femoral anteversion.
ii. Rotational profile assessment should include the knee- and foot-progression angles during gait, the thigh-foot angle, and maximum hip internal and external rotation (Figure 4). Estimate femoral anteversion by measuring the degree of internal hip rotation necessary to make the greater trochanter most prominent laterally (trochanteric prominence angle test).
iii. CT or MRI can quantify anteversion most accurately, but they are unnecessary in most cases.
i. Other common causes of intoeing include internal tibial torsion and metatarsus adductus.
ii. After age 10 years, internal rotation >70° and external rotation <20° suggests excessive femoral anteversion.
i. Shoes, orthoses, and braces are ineffective.
ii. For able-bodied children older than 8 years with unacceptable awkward gait or pain and <10° external hip rotation, a derotation osteotomy is indicated. The amount of rotation needed to correct excessive anteversion = (prone internal rotation - prone external rotation)/2.
3. Tibial torsion
i. Most evident between ages 1 and 2 years
ii. Usually resolves by age 6 years
b. Evaluation—Tibial torsion is the angular difference between the bimalleolar axis at the ankle and the bicondylar axis of the knee (normal is 20° external rotation).
i. Parent education is the primary treatment.
ii. Special shoes and braces do not change the natural history.
iii. Derotation osteotomy is rarely needed in able-bodied children.
iv. If an isolated distal tibial rotational osteotomy is performed, rotation >30° generally results in translation of the distal fragment. This is not clinically significant and will remodel quickly in growing children.
IV. Tibial Bowing
A. Overview—Three types of tibial bowing exist in children, with considerable differences in prognosis and treatment (
B. Anterolateral bowing
a. 50% of patients with anterolateral bowing have neurofibromatosis.
b. 10% of patients with neurofibromatosis have anterolateral bowing.
2. Classification—The presence of sclerosis, cysts, fibular dysplasia, and narrowing are the basis of the Boyd and Crawford classifications (
Figure 5). Neither is predictive of prognosis.
3. Natural history—Spontaneous resolution is unusual. Good prognostic signs include:
a. Duplicated hallux
b. Delta-shaped osseous segment in the concavity of the bow
[Figure 5. Classification of congenital tibial dysplasia. Type I is characterized by anterior lateral bowing with increased cortical density and a narrow but normal medullary canal; type IIA, by anterior lateral bowing with failure of tubularization and a widened medullary canal; type IIB, by anterior lateral bowing with a cystic lesion before fracture or canal enlargement from a previous fracture; and type IIC, by frank pseudarthrosis and bone atrophy with "sucked candy" narrowing of the ends of the two fragments.]
[Table 5. Types of Tibial Bowing]
a. The primary goal of treatment is prevention of pseudarthrosis.
i. A clam-shell total contact brace is used.
ii. Osteotomies to correct bowing are contraindicated because of the risk of pseudarthrosis of the osteotomy site.
iii. Fracture risk decreases at skeletal maturity.
i. All treatment options have limited success.
(a) Intramedullary rod and bone grafting
(b) Circular fixator with bone transport
(c) Vascularized fibular graft
ii. Amputation is indicated for persistent pseudarthrosis (usually after 2 or 3 failed surgeries).
C. Posteromedial bowing
1. Congenital posteromedial bowing is often confused with a calcaneal valgus foot. Dorsum of the foot may be in contact with the anterior tibia (
2. The bow improves in the first years of life, but it rarely resolves completely.
[Figure 6. A calcaneus foot is easily dorsiflexed against the tibia. A posteromedial bow of the tibia can be confused with a calcaneus foot.]
3. Must monitor for LLD—LLDs at maturity are usually in the 3 to 8 cm range (average 4 cm) and are treated as noted above in section I.
D. Anteromedial bowing—See proximal femoral focal deficiency, section V.B, below.
V. Limb Deficiencies
General principles for amputation, when indicated
1. Optimal age for amputation for limb deficiency is 10 months to 2 years.
2. Avoid early amputation if severe upper extremity deficiencies may require use of the feet for activities of daily living (ADLs).
3. Syme versus Boyd amputation:
a. The Syme amputation (ankle disarticulation) is simple and accommodates a tapered prosthesis at the ankle for optimal cosmesis.
b. The Boyd amputation (the calcaneus is retained and is fused to the distal tibia) prevents heel pad migration, aids prosthesis suspension, and may provide better end bearing. However, it also may limit prosthetic foot options because of its greater length.
Proximal femoral focal deficiency (PFFD; also called partial longitudinal deficiency of the femur) and congenital short femur
1. Overview (epidemiology)
a. The spectrum of femoral hypoplasia includes congenital short femur on the mild end to complete absence of the proximal femur on the severe end.
b. Bilateral involvement is seen in 15% of cases. Other limb anomalies are present 50% of the time.
c. There is no genetic link except in a rare auto-somal dominant form with dysmorphic facies.
2. Pathoanatomy (
a. Associated clinical problems are quite variable.
[Table 6. Spectrum of Problems Associated With Proximal Femoral Focal Deficiency (PFFD)]
b. The lower leg can appear normal despite severe upper leg involvement.
a. The thigh is short, flexed, abducted, and externally rotated (
b. Fibular deficiency occurs in 70% of PFFD patients.
i. "Extension" prosthesis
a. Initial treatment is provided when the patient is pulling to stand.
b. The bulbous segment necessary to accommodate the foot makes the prosthesis less attractive.
i. Surgery is best delayed until the patient is 2.5 to 3 years of age.
a. Indications include a predicted discrepancy at maturity <20 cm, a stable hip joint, and a functional foot.
b. Any varus, proximal pseudarthrosis, or acetabular dysplasia is addressed before lengthening.
iii. Knee arthrodesis and foot ablation
a. Indications—Foot on the affected side is at the level of the contralateral knee or higher.
b. The procedure creates a single long lever arm that is aligned with the weight-bearing line of the body, which improves prosthetic fit, function, and appearance.
c. Ideally, the short limb should be short enough that the prosthetic knee is not below the level of the contralateral knee (about 7 cm shorter) at maturity.
iv. van Ness rotationplasty
a. This procedure converts the ankle joint into a functional knee joint by rotating the foot 180°.
b. Modified below-knee (transtibial) prosthesis improves gait pattern and efficiency.
c. Indications: The foot of the affected limb lies around the level of contralateral knee, and the ankle is stable with >60° of motion.
[Figure 7. In this child with PFFD, the ankle of the affected extremity is almost at the level of the contralateral knee. The foot on the affected side is almost normal. This child would be a good candidate for knee fusion and rotationplasty.]
1. Overview (epidemiology)
a. Previously known as fibular hemimelia
b. The most common long-bone deficiency
c. No known inheritance pattern
a. It is best to think of fibular deficiency as an abnormality involving the entire limb (
b. Associated anomalies
i. Shortening of the femur and tibia
ii. Genu valgum from hypoplasia of the lateral femoral condyle
iii. Cruciate ligament deficiency
iv. Anteromedial bow of the tibia
v. Ball-and-socket ankle
vi. Equinovalgus foot deformity
vii. Tarsal coalition
viii. Absent lateral rays
a. Classically there is a short limb with an equinovalgus foot and skin dimpling over the midanterior tibia.
[Figure 8. Osseous anatomy of fibular deficiency.]
Table 7. Treatment Guidelines for Fibular Deficiency]
i. Fibula is short or absent (partial or complete hemimelia).
ii. The intercondylar notch of the femur is typically shallow and the tibial spines are small.
a. Achterman and Kalamchi classification—Based on the amount of fibula present.
b. Birch classification—Treatment guidelines based on limb length and foot function.
5. Treatment (Table 7)
a. The level or extent of fibular deficiency does not determine treatment.
b. Severity of discrepancy and foot function guide treatment.
a. Tibial deficiency was previously known as tibial hemimelia.
Figure 9. Typical clinical appearance of tibial deficiency.]
b. It has an autosomal dominant inheritance pattern. Formal genetic counseling is recommended.
c. Other musculoskeletal anomalies occur in 75% of patients.
a. Typical appearance includes a short tibial segment with a flexed knee and prominent proximal fibula. Commonly the foot is in rigid equinovarus and supination (Figure 9).
b. The presence or absence of active knee extension must be determined.
c. A proximal tibia anlage may be present but not apparent on early radiographs because of delayed ossification. An early clue to the absence of the proximal tibia is a small and minimally ossified distal femoral epiphysis.
d. Associated limb anomalies include preaxial polydactyly and lobster clawhand deformity.
3. Classification (Jones)
a. The Jones classification distinguishes partial from complete absence.
b. Partial absence is further categorized as proximal, distal, or ankle diastasis.
4. Treatment (
a. Presence of active knee extension determines treatment.
b. The proximal tibia can be present without active extension.
[Table 8. Treatment Algorithm for Tibial Deficiency]
c. The Brown procedure (centralization of the fibula under the femur to treat complete tibial absence) has a high failure rate.
d. A tibiofibular synostosis is effective at extending a short proximal tibial segment.
VI. Congenital Dislocation of the Knee
1. Congenital dislocation of the knee is a rare disorder that is commonly sporadic but occasionally occurs within families.
2. Conditions producing muscle imbalance or laxity (myelodysplasia, arthrogryposis, Larsen syndrome) are also associated with congenital dislocation of the knee.
B. Pathoanatomy—Abnormal fetal position (breech position with feet locked under the mandible), congenital absence of the cruciate ligaments, and fibrosis/contracture of the quadriceps have all been proposed as etiologic factors.
1. The knee can be hyperextended and the foot is easily placed against the baby's face. Minimal or no flexion of the knee is possible.
2. A dimple or skin crease is seen at the anterior knee.
3. Hip examination is important because an ipsilateral hip dislocation is very common (70% to 100%).
D. Classification—The spectrum has been classified from severe genu recurvatum (grade I), subluxation (grade II), and complete dislocation (grade III).
E. Treatment—The treatment of a knee dislocation takes priority over treatment of ipsilateral hip dysplasia or clubfoot. The Pavlik harness and clubfoot casts both require knee flexion.
a. Initial treatment begins with stretching followed by serial casting.
b. Flexion should be attempted only after the tibia is reduced on the end of the femur (must confirm with lateral radiograph or ultrasound). Distal femoral physeal separation or plastic deformity of the tibia is possible.
c. Prognosis is generally excellent if reduction is achieved nonsurgically.
a. Surgical treatment is indicated if nonsurgical treatment fails to reduce the tibia on the end of the femur.
b. The release always includes quadriceps lengthening.
c. Best results are seen when performed before 6 months of age.
VII. Foot Problems
A. Clubfoot (talipes equinovarus)
1. Overview (epidemiology)
a. Clubfoot is a congenital foot deformity consisting of hindfoot equinus and varus as well as midfoot and forefoot adduction and cavus.
b. It is more common in males and is the most common birth defect (1 in 750 live births).
c. Half the cases are bilateral.
d. Unaffected parents with an affected child have a 2.5% to 6.5% chance of having another child with clubfoot.
a. Potential etiologies include abnormal fibrosis, neurologic abnormalities, and arrested embryologic development.
b. Key components of the deformity are medial and plantar subluxation of the navicular on the talar head, a medially rotated calcaneus, and a shortened talar neck with medial angulation.
a. Common clinical findings are a small foot, small calf, slightly shortened tibia, and skin creases medially and posteriorly.
b. Nonidiopathic clubfeet must be identified. Clubfeet associated with arthrogryposis, myelodysplasia, diastrophic dysplasia, and amniotic
Table 9. Treatment of Residual Clubfoot Deformity]
band syndrome are resistant to casting treatment.
i. Minimal ossification of the foot in the newborn limits the utility of radiographs.
ii. In both the AP and lateral views of a clubfoot, the talus and calcaneus are less divergent and more parallel (smaller talocalcaneal angle) than normal.
iii. Radiographic appearance has poor correlation with clinical outcome.
a. The two most commonly used classification systems are those described by Dimeglio and Pirani.
b. Both classifications assign points based on the severity of clinical findings and the correctability of the deformity.
a. Nonsurgical—Ponseti serial casting.
i. Outcome is much better than with historical casting techniques (80% to 90% success versus 10% to 50%).
ii. Sequence of deformity correction is cavus, adductus, varus, and finally equinus (CAVE).
iii. Important Ponseti casting concepts
(a) Forefoot is supinated, not pronated.
(b) Lateral pressure is applied to neck of talus only.
(c) Long leg casts
(d) Weekly cast changes
(e) Percutaneous Achilles tenotomy is frequently done before final cast application to address residual equinus (up to 90% of feet).
iv. The most common cause of failure after initial correction with Ponseti casting is poor compliance with the Denis-Brown brace. Recommended use is 23 hr/day for 3 months after casting and then at night for 2 to 3 years.
v. Anterior tibial tendon transfer (split or whole transfer) is needed in one third to one half of clubfeet treated with the Ponseti method.
i. Complete posteromedial release indications: persistent deformity after casting, syndrome-associated clubfoot, and delayed presentation (older than 1 to 2 years of age).
ii. Secondary or residual deformities may require surgical intervention (Table 9).
B. Congenital vertical talus
a. Congenital vertical talus is an irreducible dorsal dislocation of the navicular on the talus.
b. Rare condition (1 in 150,000 births) commonly (~50%) associated with neuromuscular disease (myelodysplasia, arthrogryposis, diastematomyelia) or chromosomal abnormalities.
a. The navicular is dislocated dorsolaterally.
b. The deformity also includes eversion of the calcaneus, contracture of the dorsolateral muscles and Achilles tendon, and attenuation of the spring ligament.
a. Clinically, the foot has a rigid convex plantar surface with a prominent talar head (rocker-bottom).
b. Unlike flexible flatfoot, the arch will not reconstitute upon standing on the toes or hyperextending the great toe.
c. An awkward, calcaneal-type gait pattern results from limited push-off power, limited (if any) forefoot contact, and excessive heel contact.
d. Radiographs—The radiographic view that is diagnostic for a vertical talus is a lateral view in forced plantar flexion (
i. The navicular remains dorsally dislocated in this view. This differs from oblique talus, in which the navicular reduces on this view.
ii. Prior to ossification of the navicular (age 3 years), the first metatarsal is used as a proxy for the dorsal alignment of the navicular on the lateral view.
4. Differential and prognosis
a. Untreated congenital vertical talus causes significant disability.
b. Physiologic flatfoot and oblique talus are benign conditions that are easily distinguished from a vertical talus.
i. Initial treatment begins with casting.
ii. Casting is usually insufficient to correct a vertical talus but may help stretch the tight dorsolateral soft tissues.
i. Surgery is usually performed between 12 and 18 months of age.
ii. Surgical treatment includes extensive talar release with lengthening of the Achilles, toe extensors, and peroneal tendons and pinning of the talonavicular joint. The anterior tibialis is generally transferred to the talar neck.
iii. Outcome of reconstruction after age 3 years is less predictable. Triple arthrodesis is rarely needed as a salvage procedure.
C. Calcaneovalgus foot
1. Overview (epidemiology)
a. Calcaneovalgus foot is a positional deformity seen at birth. The foot is hyperdorsiflexed due to intrauterine positioning (Figure 6).
b. It is more common in girls who are first-born children.
a. A calcaneovalgus foot in newborns is a soft-tissue contracture problem.
b. No dislocation or bony deformity of the foot exists.
a. Should be passively correctable to neutral
[Figure 10. Lateral forced plantar flexion view of foot with congenital vertical talus. The first metatarsal (and unossified navicular) remain dorsally dislocated relative to the talus.]
b. Posteromedial bow of the tibia may also be present. In fact, an isolated posteromedial tibial bow is often confused with a calcaneovalgus foot.
a. Typically, the deformity will resolve without intervention.
b. Stretching may expedite the resolution of the deformity.
D. Pes cavus (cavus foot)
a. A cavus foot has an elevated longitudinal arch from medial forefoot equinus or, less frequently, from excessive calcaneal dorsiflexion.
b. Two thirds of patients with a cavus foot have a neurologic problem (most commonly Charcot-Marie-Tooth disease).
a. The primary structural problem is forefoot plantar flexion, particularly of the first ray.
b. For the lateral half of the foot to be in contact with the ground, the hindfoot must deviate into varus (
c. First ray plantar flexion may result from a weak tibialis anterior relative to the peroneus longus, but it is more commonly due to intrinsic weakness and contracture.
d. Over time, the plantar fascia contracts and the hindfoot varus deformity becomes more rigid.
a. Patients may report instability (ankle sprains).
[Figure 11. Tripod effect in a cavus foot. A, Posterior and lateral views of a cavus foot in non-weight-bearing position. The long axes of the tibia and the calcaneus are parallel and the first metatarsal is pronated. Dots indicate the three major weight-bearing plantar areas (heel and first and fifth metatarsals). B, Posterior and lateral views of a cavus foot in weight-bearing position. The long axes of the tibia and the calcaneus are not parallel. With weight bearing, a rigid equinus forefoot deformity forces the flexible hindfoot into varus. This is the tripod effect.]
b. A neurologic examination and family history are essential.
i. Unilateral involvement suggests a focal diagnosis (eg, spinal cord anomaly or nerve injury).
ii. Bilateral involvement and a positive family history are common with Charcot-Marie-Tooth disease. Despite bilateral involvement, asymmetry may be seen in children with Charcot-Marie-Tooth.
c. Hindfoot flexibility is assessed by placing a 1-inch block under the lateral border of the foot (Coleman block test).
i. The long axis of the talus will intersect the long axis of the first metatarsal dorsally on the lateral view of the foot (normally collinear).
ii. MRI of the spine is indicated with unilateral involvement.
a. Joint-sparing procedures are preferred whenever possible.
b. A key to surgical decision making is the flexibility of the hindfoot. Some general guidelines exist (
c. Percutaneous plantar fascia release is insufficient to correct a cavus foot. At minimum, an open release and soft tissue rebalancing are needed.
d. Achilles tendon lengthening should not be performed concomitantly with plantar fasciotomy. An intact Achilles tendon provides the resistance necessary to stretch the contracted plantar tissues and correct the cavus deformity.
E. Pes planovalgus (flexible flatfoot)
a. Flexible flatfoot is a physiologic variation of normal.
b. It is defined by a decreased longitudinal arch and a valgus hindfoot during weight bearing.
c. It is rarely symptomatic, is common in childhood, and resolves spontaneously in most cases.
d. Flexible flatfoot is present in 20% to 25% of adults.
a. Generalized ligamentous laxity is common.
b. Approximately one fourth of flexible flatfeet have a contracture of the gastrocnemius-soleus complex. Only these cases are associated with disability.
[Table 10. Treatment of Pes Cavus]
a. An arch should be evident when toe-standing, dorsiflexing the hallux, or not weight bearing.
b. Subtalar motion should be full and painless.
c. On a lateral radiograph, the talus is plantar flexed relative to the first metatarsal (Meary angle has a plantar apex).
d. Apparent hindfoot valgus may actually be due to ankle valgus (particularly in children with myelodysplasia). If there is any suspicion of ankle valgus, ankle radiographs should be obtained.
4. Classification and differential diagnosis
a. Flatfoot should be categorized into three groups
i. Flexible flatfoot without tight heel cord
ii. Flexible flatfoot with tight heel cord
iii. Rigid flatfoot
b. The differential of flatfoot includes tarsal coalition, congenital vertical talus, and accessory navicular.
a. No treatment is indicated for asymptomatic patients.
i. Shoes or orthoses do not promote arch development.
ii. Use of athletic shoes with arch and heel support can help relieve pain.
iii. The University of California Biomechanics Lab (UCBL) orthosis is a rigid orthotic insert designed to support the arch and control the hindfoot. The rigid material may be poorly tolerated. A soft molded insert is an alternative but may be inadequate to control hindfoot valgus.
iv. Stretching exercises are recommended if the patient is symptomatic and an Achilles contracture is present.
i. Surgery is reserved for rare cases in which pain is recalcitrant to nonsurgical treatment.
ii. A calcaneal neck lengthening with soft-tissue balancing is the treatment of choice. It corrects deformity while preserving motion and growth. Arthrodesis and arthroeisis are rarely, if ever, indicated.
F. Metatarsus adductus
a. Metatarsus adductus is a medial deviation of the forefoot with normal alignment of the hindfoot.
b. It occurs in up to 12% of newborns.
2. Pathoanatomy—Intrauterine positioning of the foot is thought to be one possible cause.
a. The foot has a kidney-bean shape (convex lateral border) and the hindfoot is in a neutral position.
b. Assess the amount of active correction by tickling the foot.
4. Classification—Bleck graded the severity of the metatarsus adductus based on flexibility. Another classification uses the heel bisector line.
5. Differential diagnosis—The differential diagnosis includes clubfoot, skewfoot (severe forefoot adductus combined with hindfoot valgus), and atavistic great toe (congenital hallux varus).
6. Prognosis and treatment
i. Spontaneous resolution of metatarsus adductus occurs in 90% of children by age 4 years.
ii. Passive stretching is recommended for mild deformity but does not improve final outcome.
iii. Serial casting is useful in children between 6 and 12 months of age with moderate deformity.
Surgery is indicated only in older children (older than 7 years) with severe residual deformity that produces problems with shoe wear and pain.
A medial column lengthening (opening wedge osteotomy of cuneiform) and lateral column shortening (closing wedge of the cuboid) produces good results with fewer complications than historical techniques.
If the child has a skewfoot (hindfoot valgus in addition to the metatarsus adductus), then hindfoot osteotomy is required in addition to the midfoot osteotomy(ies).
G. Tarsal coalition
1. Overview (epidemiology)
a. Tarsal coalition is an osseous, cartilaginous, or fibrous connection between bones of the hindfoot and midfoot.
b. It occurs in 1% to 6% of the population.
c. Most tarsal coalitions are asymptomatic.
d. 10% to 20% of patients with tarsal coalitions have two coalitions. 50% are bilateral.
e. Calcaneonavicular coalitions are the most common, followed by talocalcaneal coalitions.
Table 11. Radiographic Evaluation of Tarsal Coalitions]
a. The onset of symptoms usually coincides with the transition of a cartilaginous coalition to bone during late childhood and early adolescence.
i. Age 8 to 12 years for calcaneonavicular coalitions
ii. Age 12 to 15 years for talocalcaneal coalitions
b. Coalitions of the talus to the calcaneus can occur at any of the three facets. A middle facet coalition is most common.
a. Pain and limited subtalar motion are the hallmarks of a tarsal coalition.
i. Pain is typically in the tarsal sinus or the longitudinal arch.
ii. Patients have difficulty with uneven ground and frequent ankle sprains.
i. Plain radiographs should include AP, lateral oblique, and Harris views (Table 11 and
ii. Dorsal talar beaking is a nonspecific finding associated with a variety of coalitions. It is not a sign of degenerative arthrosis.
iii. Harris axial radiographs have a high false-positive rate for tarsal coalition. If the view is slightly oblique to the posterior or middle facet, it will appear as if a coalition is present when it is not.
iv. A CT scan helps delineate the coalition and will clarify whether the child has multiple coalitions in the foot.
[Figure 12. Images demonstrating calcaneonavicular and talocalcaneal coalitions. A, This 45° oblique view demonstrates a calcaneonavicular coalition. B, Non-weight-bearing lateral radiograph depicts a talocalcaneal coalition. There is beaking of the talus and loss of definition of the subtalar joint space. C, CT scan illustrates a talocalcaneal coalition in the left foot as viewed from the posterior.]
4. Associated syndromes—Multiple coalitions are common with fibular deficiency and with Apert syndrome.
a. No treatment is indicated for asymptomatic coalitions.
i. Management includes NSAIDs, activity modification, shoe orthoses, and cast immobilization.
ii. Not all symptomatic coalitions require surgery. 30% percent of patients remain pain free after nonsurgical cast immobilization.
i. A preoperative CT scan is helpful to rule out multiple coalitions and assess bar size.
ii. Calcaneonavicular coalition
(a) Coalition resection and interposition of extensor digitorum brevis or fat is effective in most cases.
(b) Contraindications to resection are advanced degenerative changes in adjacent joints or multiple coalitions.
iii. Talocalcaneal coalition
(a) Resection has traditionally been limited to small coalitions (<50% of middle facet) with minimal hindfoot valgus (<20°) and no degenerative arthrosis. More recent studies call these recommendations into question.
(b) Adequate excision typically involves complete excision of sustentaculum tali.
(c) If severe valgus is present at the time of coalition excision, a calcaneal osteotomy (either a calcaneal neck lengthening or medial slide) generally improves clinical outcome and decreases the risk of recurrent symptoms.
iv. A triple arthrodesis or limited subtalar arthrodesis may be indicated when there is degenerative arthrosis, multiple coalitions, or coalition resection fails to relieve symptoms.
H. Accessory navicular
a. Accessory navicular is an enlargement of the plantar medial aspect of the navicular.
b. The extra bone may be completely separate or in continuity with the true navicular.
c. It occurs in up to 12% of the population, with most being asymptomatic.
a. The accessory navicular usually does not ossify until after age 8 years. The ossicle will often fuse to the true navicular.
Figure 13. External oblique view of foot with accessory navicular.]
b. Pain is secondary to repeated microfracture or inflammatory response.
a. A firm and tender prominence on the plantar medial midfoot (distal to the talar head)
b. Often the ossicle is evident on weight-bearing AP radiographs. An external oblique view (not the commonly used internal oblique) may show the accessory navicular best (Figure 13).
a. Doughnut-shaped pads and orthotic devices that reduce direct pressure on the prominence are often effective.
b. A short-leg cast may also be effective.
c. Simple excision of the ossicle and any navicular prominence via a tendon-splitting approach (without tendon advancement) has been shown to be effective 90% of the time.
I. Kohler bone disease
a. Kohler bone disease is a self-limiting painful condition of the navicular in young children.
b. It occurs more commonly in boys than girls (4:1) and is frequently bilateral.
2. Pathoanatomy—The navicular is the last tarsal bone to ossify. It is more susceptible to direct mechanical compression injury.
a. Children with Kohler bone disease typically walk with an antalgic gait on the lateral border of the foot.
b. Radiographs confirm the diagnosis with flattening, sclerosis, and fragmentation of the navicular (
c. Irregular ossification of the navicular is common during early ossification. The diagnosis of Kohler bone disease requires clinical findings as well.
[Figure 14. Lateral radiograph of the foot of a child with Kohler bone disease. Note the sclerosis and flattening of the navicular bone.]
4. Prognosis and treatment
a. Symptoms resolve spontaneously within 6 to 15 months.
b. The navicular reconstitutes over 6 to 48 months.
c. No residual deformity or disability occurs in adulthood.
d. Casting for 4 to 8 weeks with a short-leg walking cast will decrease the duration of symptoms.
e. Surgery is never indicated.
J. Overlapping fifth toe
1. A dorsal adduction deformity of the fifth toe
2. It is typically familial and bilateral.
3. The extensor digitorum longus (EDL) tendon is contracted.
4. Treatment indicated when pain or shoe-wear problems arise. The Butler procedure involves a double racket-handle incision and release of the EDL.
K. Curly toes
1. A malrotation and flexion deformity of one or more toes
2. A contracture of the flexor digitorum longus (FDL) or flexor digitorum brevis (FDB) is the most common cause.
3. Treatment involves FDL tenotomy around age 3 to 4 years.
1. Polydactyly occurs in 1 in 500 births.
2. Postaxial polydactyly is most common and has an autosomal dominant inheritance pattern in some families.
3. Surgery is indicated to facilitate shoe wear and prevent toe deformities.
Top Testing Facts
1. Estimates of the yearly growth contribution of the distal femur and proximal tibia physes (eg, 10 mm/year for distal femur) are valid for only the last 4 years of growth.
2. Limb equalization procedures must take into account the final projected LLD, not the LLD present at the time of surgery. If the current LLD is used, the LLD will be undercorrected.
3. Undercorrection of an LLD associated with paralysis facilitates the foot clearing the floor during the swing phase of gait and is especially important if the patient walks with a brace in which the knee is locked in extension.
4. A proximal fibular epiphysiodesis should be included with proximal tibial epiphysiodesis if more than 2 to 3 years of growth remain.
Tibia Vara (Blount Disease)
1. Beware of internal tibial torsion with tibia vara. The patella should be pointed directly anterior on all weight-bearing lower extremity radiographs.
2. To avoid undercorrection, fix the distal fragment in slight valgus, lateral translation, and external rotation.
3. The risk of postoperative compartment syndrome is decreased if an anterior compartment fasciotomy is performed at the time of surgery.
4. Confirm the new mechanical alignment on the surgical table with bovie cord. A cord held directly over the center of the femoral head and ankle should pass over the lateral tibial plateau.
5. One or two pins and a cast is all the fixation necessary for infantile cases. Plate or external fixation is necessary for fixation in adolescent Blount disease.
6. Recurrence is less when the osteotomy is done before age 4 years.
1. Anterolateral bowing is typical of congenital pseudarthrosis of the tibia and is often associated with neurofibromatosis.
2. Posteromedial bowing is often associated with development of a limb-length discrepancy.
1. Unilateral genu valgum following a Cozen fracture almost always resolves spontaneously.
2. Physeal tethers must be placed extraperiostally to avoid unintended arrest.
3. Physeal tethers (staples or eight-plate systems) must be placed in the midcoronal plane to prevent recurvatum or procurvatum deformities.
4. Nomograms are available to appropriately time a permanent hemiepiphysiodesis (or predict the duration necessary for correction with a temporary physeal tethering).
1. Brace-dependent ambulators (eg, patients with cerebral palsy or myelodysplasia) tolerate less tibial torsion because the compensatory mechanisms (knee and subtalar joint motion) are unavailable.
2. Lever-arm dysfunction in children with neuromuscular disorders is the reason osteotomies are frequently indicated in such children.
3. Estimate anteversion clinically by measuring the degree of internal rotation of the hip necessary to make the greater trochanter maximally prominent laterally (trochanteric prominence angle test).
4. Amount of rotation to correct excess anteversion = (prone internal rotation - prone external rotation)/2.
5. If an isolated distal tibial osteotomy is performed, rotation of >30° generally results in translation of the distal fragment. This is of no clinical consequence and will remodel rapidly in growing children.
1. Optimal age range to perform amputation for limb deficiency is age 10 months to 2 years.
2. Avoid early amputation if severe upper extremity deformities may require the use of the feet for activities of daily living.
3. The Syme amputation is simple and accommodates a tapered prosthesis at the ankle for optimal cosmesis.
4. The Boyd amputation prevents heel pad migration, aids prosthesis suspension, and may provide better end bearing; however, it also may limit prosthetic foot options because of excessive length.
5. In tibial deficiency, a good early radiographic clue to the absence of the proximal tibia is a small and minimally ossified distal femoral epiphysis.
6. The Brown procedure has a high failure rate. In contrast, a tibiofibular synostosis is effective at extending a short proximal tibia segment.
1. The sequence of deformity correction with the Ponseti technique is cavus, adductus, varus, equinus (CAVE).
2. The most common cause of a late failure after initial clubfoot correction with Ponseti casts is poor compliance with the Denis-Brown brace.
3. Most clubfeet treated with the Ponseti method (up to 90%) require percutaneous Achilles tenotomy at the time the final cast is applied.
4. Anterior tibial tendon transfer (split or whole transfer) is needed in one third to one half of clubfeet treated with the Ponseti method.
5. Percutaneous plantar fascia release is insufficient to correct a cavus foot.
6. Congenital vertical talus is associated with neuromuscular disease and/or genetic syndromes in up to 50% of children.
7. The diagnostic radiographic view for congenital vertical talus is the forced plantar flexion lateral view.
8. Unless proven otherwise, a child with pes cavus should be assumed to have an underlying neurologic condition causing the deformity. Charcot-Marie-Tooth disease is the most common etiology of pes cavus in children.
9. Simultaneous plantar fascia release should be avoided with an Achilles tendon lengthening. An intact Achilles tendon provides the resistance necessary to stretch the divided plantar tissues.
10. Preoperative CT assessment is helpful before tarsal coalition excision because multiple coalitions are present in 10% to 20% of feet with tarsal coalition. A calcaneonavicular coalition is most common.
11. Apparent hindfoot valgus may actually be the result of ankle valgus. If there is any suspicion of ankle valgus, radiographic views of the ankle should be obtained.
12. Severe forefoot adductus combined with hindfoot valgus is a condition known as skewfoot. Although rare, it is important to recognize because correction requires both hindfoot and midfoot osteotomies.
13. An iatrogenic skewfoot deformity is possible when correcting adductus with serial casts. The hindfoot must be maintained in a neutral or slight varus position.
14. Harris axial radiographs have a high false-positive rate for tarsal coalition. If the view is slightly oblique to the posterior or middle facet, it will appear as if a coalition is present when it is not.
15. Beware of interpreting irregular ossification of the navicular as indicative of Kohler bone disease. Irregular ossification is common during early ossification. Clinical findings are always present with Kohler bone disease.
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