Fractures-décollements épiphysaires de type SalterII de l’extrémité distale du fémur chez l’adolescent : nouvelle proposition thérapeutique (étude préliminaire)

Abstract

The prognosis of distal femoral physeal fracture-separation is poor in children. In adolescents, more than half of the cases are classified as Salter and Harris type-II. The gold-standard treatment for a displaced fracture combines anatomic reduction with internal fixation with a pin or screw, preserving the growth cartilage. Despite this treatment, the rate of mid- and long-term complications has been high in the literature, most problems being related to leg length discrepancy and misalignments (genu valgum and genu varum). In order to avoid these problems, for adolescents, we propose and osteosynthesis system which bridges the entire growth cartilage with a blade-plate. Depending on the bone age, puberty and thus potential for further growth, we combine this osteosynthesis with a contralateral distal femoral epiphysiodesis to prevent invalidating leg length discrepancy. We reviewed retrospectively the cases of 21 patients aged 11 to 15 years treated between 1990 and 2005 for Salter and Harris type-II distal femoral physeal fracture- separation. Clinical and radiographic outcome was compared between the 16 patients treated with the classical internal fixation system or cast immobilization and the five patients treated with a blade-plate. A complete physical examination was available for the follow-up in all cases. A full stance view was used for the radiographic analysis. The mean follow-up was 6.7 years (range 2-17), minimal two years. In patients treated with the classical fixation system or a plaster cast, four of 16 (25 %) developed frontal misalignment of more than 5 degrees and five of 16 (32 %) leg length discrepancy of more than 2cm. No misalignment or leg length discrepancy (>2cm) was observed among the five patients treated with a blade-plate. The results observed in our patients treated with the classical fixation systems are comparable with those reported by others. Our patients treated with the blade-plate system constitute the only series with no cases of frontal misalignment or invalidating leg length discrepancy after this type of fracture. We used contralateral distal femoral epiphysiodesis in all patients whose predictable leg length discrepancy at the end of growth was greater than 2cm, that is 11-3.5 years (bone age) in girls and 13-14.5 years in boys. Internal fixation techniques bridging the growth cartilage are the only techniques used for Salter and Harris type-II distal femoral physeal fracture-separation in adolescents which have been able to prevent posttraumatic knee misalignment (genu valgum or genu varum). Leg length discrepancy can be prevented by a contalateral distal femoral epiphysiodesis when the fracture occurs in a child or early puberty.