[Elastic sliding central medullary nailing with osteogenesis imperfecta. Fourteen cases at eight years follow-up].

PURPOSE OF THE STUDY: Elastic sliding centromedullary nailing (ESCN) proposed by Métaizeau in 1987 for the prevention and treatment of limb fractures in osteogenesis imperfecta has never been evaluated. A multicentric serie was studied in order to evaluate results of these procedure.
MATERIAL AND METHODS: Thirty-six ESCN procedures were performed in fourteen patients. Percutaneous pinning was used for the femur and distal tibia and arthrotomy for the distal femur as needed and in all cases for the proximal tibia. The pins were bent in compliance with the principles of the ESCN system. The ends of the pins were bent back to form a U pushed into the epiphysis. Reaxing osteotomies required minimal incisions. Age at the first procedure, the number of procedures and complications, and time between procedures were recorded. Pin overlap and the angle formed were also recorded. Pin gliding was evaluated. Ability to walk with or without assistance was noted.
RESULTS: The medullary canal measured 4 to 10 mm. The first procedure was performed at a mean age of four years (range 15 days to 10 years). Follow-up was eight years (range 1-12). There were 2.5 procedures per patient (range 1-5). Pins had to be changed in 75% of the bone segments. Mean time between two procedures was 3.2 years. There were no cases of defective sliding or infection. There were four cases of secondary fracture with a mean 30% pin overlap, two pin migrations, one nonunion, and one shortening. The majority of the complications occurred after the age of five years. At last follow-up, three patients could not walk, four walked with aids, and eight without aids. DISCUSSION: The advantages of the technique (size of the pins, nailing without reaming, pin sliding in all cases, low cost) must not overshadow the drawbacks (risk of pin deformation and migration, secondary fracture). Secondary fractures might be limited by discrete valgus of the femoral shaft and preventive pin change when the angle formed approaches 30 degrees and when there is only 30% overlap left. Use of telescopic nails before the age of five years increases the risk of complications while most of the complications observed with ESCN occur after the age of five years. Twenty-five percent of the ESCN complications involved only the femur. The percent of secondary fractures was less than with telescopic nailing (3.6% versus 11%) but there were more cases of nail migration. All pins slid, compared with 6% failure of elongation with telescopic nails. Although proof is not available, surgical treatment of osteogenesis imperfecta before the age of five years appears to provide more rapid functional progress.
CONCLUSION: Sliding centromedulary nailing is an attractive alternative before the age of five years. In older children and to the end of growth, telescopic nail or pinning should be discussed although pinning may permit more secondary fractures which can be limited by rigorous surveillance of pin position.