Measurement:
(1) The knee and ankle joints should be bent to 90°.
(2) Measure the distance from the bottom of the foot to the anterior of the knee. This measurement need to be taken consistently, since the knee has some length. Based on some trials, the equations appear to use the top of the knee (with knee and ankle at 90°, the distance from the plane of the top of the thigh to the bottom of the foot).
White Females
Chumlea (1994)
height of white females 6-18 years old in cm =
= (2.15 * (knee height in cm)) + 43.21
Zorab et al (1963)
height in cm for tibia 29 to 39 cm =
= (2.53 * (length of tibia in cm)) + 67.22
White Males
Chumlea (1994)
height of white males 6-18 years old in cm =
= (2.22 * (knee height in cm)) + 40.54
Zorab et al (1963)
height in cm for tibia 30 to 44 cm =
= (2.92 * (length of tibia in cm)) + 49.84
Black Females
Chumlea (1994)
height of black women 6-18 years old in cm =
= (2.02 * (knee height in cm)) + 46.59
Black Males
Chumlea (1994)
height of black males 6-18 years old in cm =
= (2.18 * (knee height in cm)) + 39.60
Limitation:
• The equations assume that the input data for the knee height is appropriate for the patient's age.
