[Tibia vara in adolescents. Apropos of 19 cases].

Purpose Of The Study: Clinical, and radiological aspects and treatment of adolescent tibia have been studied in a review of 19 children native of the Caribbean.

Material: 23 cases of adolescent tibia vara in 19 children have been collected (14 males and 5 females, aged from 9 to 14).

Methods: Clinical aspects (weight, lower limb axis), radiological signs (aspect of the physis, mechanical axis, epiphyseal slope) were studied pre and post-operatively.

Results: All the boys presented an important overweight. Pain was the first symptom, characterized by a progressive varus deformity on a leg which was previously straight. Radiological findings consisted in metaphyseal varus and widening of the medial part of the physis. Mechanical femoro-tibial axis varied from 10 degrees to 55 degrees varus, medial epiphyseal slope from 12 degrees to 30 degrees. Average mechanical femoral angle was 92 degrees and accounted for a mean femoral varus deformity of 4 degrees. 23 knees were operated, 4 after fusion of the whole physis. 10 lateral hemi-epiphysiodesis were performed with a mean correction of 4 degrees every year until fusion. In 3 cases a tibial osteotomy was made in a second time, at the end of growth. In 6 cases of late treated patients, an isolated tibial osteotomy of valgisation was performed. In 7 cases of important deformity before closure of the physis, tibial osteotomy was associated with lateral epiphysiodesis. In one case, a lateral closing wedge osteotomy was performed, associated to an elevation of the medial tibial plateau and a lateral hemi-epiphysiodesis.

Discussion: Histopathological examination of the physis showed similarities between adolescent tibia vara, infantile tibia vara and Slipped capital femoral epiphysis: the entire physeal plate was involved. Concerning pathogenesis of adolescent tibia vara, mechanical factors are predominant, with abnormal pressures across the medial part of the physis.

Conclusion: Adolescent tibia vara occur in obese black children and can be considered as an epiphysiolysis of the upper end of the tibia.