Tibial torsion, Internal (Pediatric)

INTRODUCTION

Definition

A condition characterized with internal rotation of tibia. 

Epidemiology

• Most common cause of inward turning of toes (intoeing in toddlers).
• Most evident between ages 1 and 3 years.
  • Usually seen during 2nd year of Life.
• Usually resolves by age 4-6 years.
• It is often bilateral (2/3 of affected infants).
• Unilateral internal tibial torsion is seen twice as often on left side as on the right side.
• The condition affects both sexes equally.

Etiology

The exact etiology is unknown. It is believed to be caused by intra-uterine positioning and molding.

Pathogenesis

The condition may be secondary to excessive medial ligamentous tightness.

Differential Diagnosis

Differential diagnosis of intoeing:

• Metatarsus adductus
• Tibial torsion.
• Femoral anteversion.
• Cerebral palsy (can be an early cause of tibial intoeing).

Causes of Intoeing
Condition	Findings
Tibial Torsion	Thigh-foot angle > 10° internal
Femoral Anteversion	Internal rotation > 70° and < 20° of external rotation
Metatarsus Adductus	Medial deviation of the forefoot (abnormal heel bisector), normal hindfoot

CLINICAL FEATURES

Symptoms

The condition is usually asymptomatic but it causes a pigeon-toed gait (legs are “turning in”), commonly noticed once child begins walking. There is an increased risk for tripping and/or falling (child may appear clumsy). 

Signs

Inspection: 

• The feet are medially rotated, while patella remains in neutral position.

Assess the rotational profile: 

• Foot progression angle: A rough measurement which is obtained during gait by observing the angle of the foot off of the line of progression, which is a result of hip rotation, tibial torsion and shape of foot.
  • Measure angle between foot position and imaginary straight line while walking. 
  • Observe thtat severe foot deformities (clubfoot) may interfere with the usual measurement.
  • Normal is -5 to +20°.
  • Besides internal tibial torsion, metatarsus adductus will decrease the angle. 
• Thigh foot angle/axis: Used to quantify tibial torsion.
  • Measurement: Done with the child in the prone position and the knee flexed 90°. The angle is formed by a line bisecting the foot and line bisecting the thigh
  • Values: 
    • Infants- mean 5° internal (range, −30° to +20°).
    • By age 8 years, mean normal is 10° external (range, −5° to + 30).
• Transmalleolar axis: The angular difference between the bimalleolar axis at the ankle and the bicondylar axis of the knee.
  • Measurement: The angle is formed by an line from the lateral to the medial malleolus, and a second line from the lateral to the medial femoral condyles.
  • Values: Normal is 20° of external rotation.
    • Average is 0 to -10° internal rotation in childhood.
    • Abnormal is greater than 15° internal rotation.
• Hip internal rotation: To identify increased femoral anteversion.
• Heel bisector line: To identify metatarsus adductus.

Associated Conditions

Can be associated with metatarsus adductus (1/3) and developmental dysplasia of the hip (DDH).

DIAGNOSIS

Conventional Radiography

Radiographs are usually not indicated unless other conditions present.

Computer Tomography (CT)

CT may be utlized for surgical planning.

Magnetic Resonance Imaging (MRI)

MRI may be utlized for surgical planning.

TREATMENT

Overview

The condition resolves spontaneously with growth. 

Nonoperative Treatment

Indication: Most cases
Method:

• Observation and parental education is the primary treatment.

Outcomes: 

• Usually resolves spontaneously by age 4.
• Special shoes and bracing/orthotics (Denis Brown) will not change the outcome.

Operative Treatment

Indication: Rarely necessary except in severe cases with marked functional and/or esthetic deformity. The thigh-foot angle should be > 15°.
Method: Derotational osteotomy (supramalleolar tibial osteotomy) when the child is between 7 and 10 years of age (usually older than 8 years).

Operation Method

Derotational supramalleolar tibial osteotomy:

• Indication: Rarely required. Should be performet in children > 6-8 years of age with functional problems. The thigh-foot angle should be > 15°.
• Method: Osteotomy fixed with plate or smooth K wires. Intramedullary nail fixation is used in skeletally mature patients.
  • Supramalleolar tibial osteotomy is associated with lower complications than proximal osteotomy.