Recurrence After Surgical Intervention for Infantile Tibia Vara: Assessment of a New Modified Classification.

ABSTRACT

BACKGROUND: To propose a modified classification of infantile tibia vara based on the morphology of the metaphyseal/epiphyseal tibial slope that better correlates with treatment outcomes than the traditional Langenskiold classification. METHODS: We performed a retrospective review of 82 patients and 115 limbs that underwent surgery for infantile tibia vara over a 22-year period (1990 to 2012) at a single institution. A modified Langenskiold classification was applied to all patients preoperatively and the outcomes were assessed. The modified system created a 3-stage classification (types A, B, and C) type A has a partially lucent medial metaphyseal defect, with or without "beaking"; type B deformity has downward-sloping curvature of the lateral and inferior rim of a completely lucent metaphyseal defect, which then has an upslope at the medial rim, resembling a ski-jump, with no epiphyseal downward slope; type C has vertical, downsloping deformity of both the epiphysis and metaphysis, with no upward curvature projecting medially at the inferior extent, while the epiphysis slopes downward into the metaphyseal defect. RESULTS: Sixty-seven limbs did not develop recurrence following corrective osteotomy, whereas 48 limbs required at least 1 repeat surgery for recurrent deformity. Preoperative mechanical axis deviation, medial proximal tibial angle, lateral distal tibial angle, and body mass index did not differ significantly between those with recurrence and those with without. Mean age at surgery was significantly different for those who developed recurrence compared with those who did not. Patients without recurrence were 4.3 years of age (range, 2.4 to 10.3 y) compared with 6.2 years of age (range, 2.9 to 10.1 y) for those who recurred (P<0.01). Of patients who developed recurrent deformity, there were significantly more patients with type C changes (71.7%, P<0.01) then either type A (22.5%) or type B (20.7%). High rates of recurrence were seen for both Langenskiold stage III (50%) and stage IV (69.6%). CONCLUSIONS: Consistent with prior studies, age 5 seems to be a critical transition in the risk for recurrent deformity after tibial osteotomy. Extreme vertical sloping of the medial metaphyseal defect, as in some classic Langenskiold III lesions and more precisely described by type C in a newer, modified classification, carries a poor prognosis for successful correction by high tibial osteotomy alone or in combination with epiphysiolysis. LEVEL OF EVIDENCE Level II.