This presents the greatest disparity between familial concern and disease.
Version refers to normal axial rotation of a long bone. In the femur, this is the angle subtended between the neck and condyles, normally anteriorward 30 degrees at birth declining to 12 degrees at maturity. In the tibia, it is measured as the transmalleolar axis, with the knee as a neutral
reference: normal is 5 degrees at birth increasing to 15 degrees lateralward at maturity.
End of day
Interferes with falling asleep
Other soft tissue change
A Leg aches Distinguishing characteristics.
A Foot progression angle.
B Hip rotation test Prone position allows simultaneous evaluation to expose asymmetry from side to side and of all sites (hip, transmalleolar axis, and foot) of rotation. Asymmetric loss of medial rotation of the hip (red) is a concerning sign. In the patient pictured below, the feet easily rest on the table due to severe antetorsion (90 degrees+)
C Range of rotation for hip and leg Ranges by the end of the first decade. Total arc at the hip is 100 degrees. Medial rotation of the hip declines while lateral rotation increases with age, as degenerative disease contracts the capsular fibers.
D Measurement of tibial rotation Thighfoot angle is subtended between the long axis of the thigh and of the foot (gray). Transmalleolar axis is the angle subtended by a line drawn through the malleoli and a line drawn perpendicular to the axis of the thigh (blue).
E CT in preparation for operative correction of torsion Rotational malalignment results in lateral patellar dislocations. The femora are rotated medialward (red), while the tibiae rotate lateralward (green). The opposite rotation wrings the lower limb to drive the patella (white) out of the trochlea (orange).
F Algorithm for in-toeing Numbers indicate age in years by which component of in-toeing resolves spontaneously in most cases. Boxes below abscissa indicated period of treatment if indicated.
Torsion refers to abnormal version, > or < 2 standard deviations from the mean. For example, in the proximal femur, “antetorsion” is preferable to “excessive anteversion.” “Retrotorsion” signifies neck inclination 15 degrees to 0 degree. Retroversion is abnormal per se.
Rotation may be described as medial and lateral, or internal and external. The latter distinguishes rotation as a movement.
History This is essential to acknowledge the concerns of the family.
Physical examination Determine the rotational profile, which has the following components.
FOOT PROGRESSION ANGLE This is the angular difference between the axis of the foot and line of progression walking [A].
FEMORAL VERSION Measure hip rotation prone [B]. Significant asymmetry may be a sign of focal disease (e.g., slipped capital femoral epiphysis). Identify the midpoint between medial and lateral rotation, a measure of resting rotation. Normal medial rotation is <70 degrees; >90 degrees, which requires moving the limb off the side of the table, is considered severe [C]. A child with femoral antetorsion sits in a W position. The patellæ “squint” or “kiss” in the standing position. Running is characterized by an “eggbeater” pattern, as the legs flip out during swing phase.
ANGLE OF TIBIAL ROTATION This may be determined by thigh-foot angle or transmalleolar axis [D]. Thigh-foot angle is a measure of both leg (ankle) and foot (subtalar) rotation, whereas transmalleolar axis isolates the leg. In an infant, thigh-foot angle has wide variation due to ligamentous laxity: minimize this by guiding the foot to its neutral position rather than manipulating it into position. In an older child, it may be compared with transmalleolar axis to estimate contribution of hind foot rotation.
Foot Examine the lateral border of the foot. This may be convex in metatarsus adductus, thereby producing in-toeing. It may be concave in forefoot abductus, as in flatfoot or overcorrected clubfoot. An adducted hallux, dynamic or static, may give the appearance of in-toeing.
Imaging Consider imaging for concerning sign, such as asymmetry of hip rotation, or as part of operative planning. For the former, start with screening röntgenogrammes. For the latter, CT measures rotation [E].
Management The natural history of torsion is unaffected by manipulative therapy or bracing. Sitting in the W position is OK. Twister cables are not OK. Each component of torsion resolves spontaneously in the majority of patients with growth over the first decade [F]. In the young child, it is difficult to determine the functional impact of torsion, for example, frequent falling is more likely due to judgment and development of gait mechanics than to torsion, unless severe. In fact, medial torsion may be advantageous in rectifying the course of tibialis posterior and poising the subtalar joint to lock, thereby expediting push-off. Conversely, increasing lateral rotation reduces lever arm of the foot, thereby weakening push-off. Appearance is determined by the family and often is a significant cause for consultation.
There is no evidence that persistent femoral antetorsion accounts for long-term morbidity such as osteoarthritis. Femoral retroversion is abnormal and is associated with slipped capital femoral epiphysis and femoroacetabular impingement.
Only operation can change long bone torsion. This is indicated in < 1% of patients, and after 8 years of age. Torsion must be severe, clearly a cause of dysfunction, and natural history must be allowed to complete
its course. This is most likely in opposing or “miserable” malalignment [E], which is deleterious to the patellofemoral articulation, accounting for pain and patellar instability.
FEMORAL OSTEOTOMY This may be performed proximal or distal. Proximal incision may be covered more readily by clothing. Intertrochanteric osteotomy allows level proximal to trochanter minor, which heals readily and takes advantage of iliopsoas to add compression. Operation in the prone position, while requiring familiarity (“upside down”), allows comparison of both lower limbs for symmetry. Use a high angle plate (120 to 130 degrees) with longest blade into the head of the femur. This will provide an internal strut in the neck as protection against future osteoporosis.
TIBIAL OSTEOTOMY This is performed proximal to the tibial tubercle to correct patellofemoral malalignment. Distal metaphysial osteotomy is easier [G]. Cut the fibula for severe deformity. Add fasciotomy of the anterior crural muscle compartment to reduce risk of compartment syndrome. Plate fixation forgoes cast. Wire fixation allows more distal osteotomy for healing, and implant removal in clinic.