Early Proximal Tibial Valgus Osteotomy as a Very Important Prognostic Factor in Thai Children with Infantile Tibia Vara
Kamolporn Kaewpornsawan, MD*, Suksan Tangsataporn, MD*, Ratiporn Jatunarapit, BNS*.
Affiliation : * Department of Orthopedic Surgery, Faculty of medicine, Siriraj Hospital, Mahidol University
Objectives : To find the effectiveness of the early surgery (2-3 years of age)as a very important prognostic factor
affecting the outcomes in Thai children with infantile tibia vara and all the prognostic factors including the
usefulness of arthrographic study in correcting the deformity.
Materials and Methods : From1994 to 2004,sixteen children aged average 3.61 years old (2.08-7.0) were
treated in Siriraj Hospital and diagnosed as infantile tibia vara by Langenskiold radiographic staging were
included in the present study and retrospectively reviewed with an average of 6.4 years follow up(range 6
month – 11.1 years). All cases were initially treated by surgery because of low compliance for brace or brace
failure.They consisted of 3 boys and 13 girls. There were 24 legs including the bilateral involvement in 8 cases
(2 boy and 6 girls). After arthrography, the midshaft fibular osteotomy was performed then the proximal tibial
dome-shaped valgus osteotomy was done and fixed with 2 pins.The desired position was 12 degree knee
valgus . The patients were divided in two groups, 1)group A,the successful group with the knee becoming
normal without any deformity after single osteotomy,2)group B,the recurrent group with recurrence of the
varus deformity required further corrective osteotomies to make normal axis of the knee. All variables were
analyzed and compared between group A and group B. The general characteristics and radiographic findings
were recorded in 1)age, 2)sex, 3)side, 4)weight in kilogram and in percentage of normal or overweight(obesity)
compared with the standard Thai weight chart, 5)tibiofemoral angle (TFA) pre and postoperative treatment,
6) metaphyseal diaphyseal angle (MDA), 7)the medial physeal slope angle(MPS, 8)The preoperative
arthrographic articulo-diaphyseal angle (ADA), 9.arthrographic articulo-medial physeal angle (AMPA).
Results :There were 14 legs in group A and the remaining 10 legs were in group B (average 2.4 operations).All
cases healed in good alignment of the legs without major complication .All patients who were operated on
early before 3 years old were 100% cured by single osteotomy in group A( 11 legs).Arthrography was useful
in evaluating the knee joint and drawing the angle. Considering the prognostic factors affecting the outcomes
after surgery, there were 6 prognostic factors . First, the age less than 3 years old (P<0.001). Second, the
normal weight (P<0.047). Third, the Langenskiold stage 1-2 (P=0.002). Fourth, the MPS angle equal or less
than 59 degree (P < 0.001). Fifth, the ADA preperative angle equal or less than 18 degrees (P<0.001). Sixth
and the last factor,the TFA angle postoperative treatment, equal or more than 10 degrees valgus(mean 13
degrees valgus) (P=0.009).In multivariate analysis with stepwise logistic regression of these 6 prosnostic
factors, the MPS angle had the most important significance. The proximal tibial valgus osteotomy was a very
important factor(P < 0.001).
Conclusion : The 6 prognostic factors and usefulness of arthrography were identified. The authors suggest that
surgery should be performed early in Thai children who have met these criterias 1)age of the patients more
than 2 years old , 2)Langenskiold roentgenographic characteristics of infantile tibia vara stage 2 or more at
the time of diagnosis, 3)Low compliance for brace treatment.or brace failure but not more than 3 years old.
The surgery should not be delayed more than 3 years of age by waiting for effectiveness of brace treatment in
Thai children with infantile tibia vara. The early proximal valgus dome- shaped osteotomy was a very impor-
tant controllable prognostic factor by surgeon decision.
Keywords : Early surgery, Infantile tibia vara, Prognostic factaphy
