tibial femoral angle

The natural history of the tibial femoral angle is one of considerable genu varum or bowing at birth, approximately 15 degrees. There is gradual spontaneous correction to zero degrees at one and one-half to two years of age. During the next year, a valgus of 10 degrees to 12 degrees develops which gradually corrects to the normal adult value of 5 to 6 degrees valgus at about age seven years. This process is identical in boys and girls.

Diagnosis

Clinical diagnosis and x-rays are not required. Observation of child walking:
Knee caps point forward
Femur external
Tibial internal rotation cancels femur rotation
Foot points inward (due to tibial rotation)

Measuring degree of genu varum:
Child stands with medial malleoli touching
Measure distance between medial femoral condyles

http://www.doctorslounge.com/pediatrics/diseases/genuvar.htm

Normal limits of knee angle in white children--genu varum and genu valgum.

Normal limits of knee angle in white children--genu varum and genu valgum. ³

---

Heath CH. Staheli LT. Journal of Pediatric Orthopedics. 13(2):259-62, 1993 Mar-Apr. Knee angle and intermalleolar (IM) or intercondylar (IC) distance were measured in 196 white children aged 6 months to 11 years to establish normal limits of tibiofemoral angle. Children were maximally bowlegged at * age 6 months and progressed toward approximately neutral knee angles (0 degree) by age 18 months. Greatest mean knock knee of 8 degrees was observed at age 4 years, followed by a gradual decrease to a mean of less 6 degrees at 11 years. Normal children aged 2-11 years had knock knee up to Á 12 degrees and intermalleolar distance up to 8 cm; the existence of bowlegs after age 2 years was abnormal. *

http://www.wheelessonline.com/ortho/pediatric_genu_varum

measurement of bow leg deformity

Physiological bowing and tibia vara. The metaphyseal-diaphyseal angle

---

in the measurement of bowleg deformities. Levine-AM; Drennan-JC J-Bone-Joint-Surg-Am. 1982 Oct; 64(8): 1158-63 The metaphyseal-diaphyseal angle is the angle created by the intersection of a line through the transverse plane of the proximal tibial metaphysis with a line perpendicular to the long axis of the tibial diaphysis. This angle represents the degree of deformity of the proximal end of the tibia in a patient with clinical bowleg deformity and permits early differentiation between infantile tibia vara and physiological bowleg, before the appearance of the radiographic changes of tibia vara. In twenty-nine of thirty affected extremities with an initial metaphyseal-diaphyseal angle of more than 11.0 degrees, radiographic changes of tibia vara later developed. However, only three of fifty-eight extremities with a metaphyseal-diapyseal angle of 11.0 degrees or less had any of the diagnostic changes. In addition, the ratio of the metaphyseal-diaphyseal angle (proximal tibial metaphyseal deformity) to the tibiofemoral angle (deformity of the entire extremity) showed that approximately 60 per cent of the deformity in tibia vara originates in the proximal metaphysis, whereas only 20 per cent of the deformity in physiological bowing originates there. The metaphyseal-diaphyseal angle allows accurate early diagnosis of bowleg deformity, as well as accurate assessment of its progression.

severe rickets

Here is an example of severe rickets. There has been a lack of vitamin D for a long enough period of time for skeletal deformities to develop. The growth plate is not normal (compare to previous image). The growth plate is no longer smooth and has a ragged apperance. This is an indication that bones are not being calcified properly. The bones have lost their reticular pattern and have developed coarse trabeculations. The cortex has linear lucencies that are indicative of pseudofractures. These are simply poorly mineralized areas across the bone.


http://rickets.stanford.edu/pages/case04.html‎

mild rickets

There is a ragged metaphyseal side to the growth plates of the radius and ulna. These bones are affected because they are undergoing rapid growth. The cartilage continues to grow abnormally in the physis. Calcification spicules occur at the ends of the bone, creating the appearance of a little cup holding a bowl of cartilage, with the epiphyseal center (calcified bone) present as a ball in the bowl.

This patient was treated with vitamin D. This x-ray was taken a month later. The cartilage that had piled up near the growth plate has begun to calcify.

http://rickets.stanford.edu/pages/case04.html‎

This x-ray shows a widened growth plate with an irregular pattern on the metaphyseal side.

This is an x-ray of the same patient taken after treatment with calcium and vitamin D. The growth plate has been reduced to its normal width as the cartilage has begun to calcify. The margin is smooth and clean on the end of the ulna. The calcification bands are visible on both radius and ulna.

http://rickets.stanford.edu/pages/case04.html‎

This is and anterior-posterior view of a patient with rickets involving the skull. The sutures are relatively wide in this skull due to an increase in intracranial pressure bfore the sutures have united. The sutures are approximately 4 cm wide which is abnormal.

This is a lateral view of the same skull. The sutures are wider than normal and can also be seen from this angle.

http://rickets.stanford.edu/pages/case04.html‎

rickets

This is an anterior-posterior view of a growing child. This bowing results from chronic illness with prolonged stress. The weight-bearing tibiae, soft with excess cartilage, bend easily.

This is a lateral view of the same patient. The curving of the tibia is easily visible. The growth plate looks normal since treatment has begun, but the bowing of the legs remains.

rickets.stanford.edu/pages/case04.html‎

Rickets

Two and a half year old asian child, failure to walk and thrive.
There is widening of the epiphyseal plate with visible soft tissue swelling separating epiphyses and metaphyses. The metaphyses are broadened and cupped around the epiphyses, particularly of radius ulna and metacarpals. The provisional zone of sclerosis in the metaphyses is widened amd more instense than normal. The bone trabecular detail is blurred. A line of 'lucency' in the cortex on the medial side of the distal ulna on the right resembles sub-periosteal bone resorption.