[Effect of osteotomy metal plate anastomosis with the femur on stimulation of lower femur growth in children].

The aims of this study were (1) to examine structural, electrostatic and thermal changes taking place in the vicinity of a metal plate; (2) to establish factors that affect the growth of the operated extremity; (3) to quantify the extent and dynamics of growth enhancement depending on retention time of the plate and distance of the plate from growth cartilage; and (4) to draw practical conclusions. The study consisted of an experimental and a clinical part. The experimental part was done in 45 children aged 2 to 14 years and included histology of tissues sampled from the vicinity of bone fixation, examination with a thermographic camera of temperature distribution around the operated hip joints, and measurements of the electric potential between the plate stabilizer and femur. In the clinical part, an orthopedic examination was performed in 100 children treated surgically between 1990 and 1993 at the Department of Pediatric Orthopedics of the Pomeranian Academy of Medicine. In order to reveal any differences in limb length and to verify the measurements done with a tape, AP radiograms of femoral bones with both epiphyses were obtained. The following conclusions were drawn from the results: (1) In the vicinity of the metal plate, processes of remodeling and destruction take place, most evident in the area of contact between the plate and bone; (2) Brown amorphous deposits of iron were present in all samples from the vicinity of bone fixation; (3) Temperatures near the operated joint were highest during the first six months after surgery and gradually decreased thereafter; (4) The electric potential between the plate and bone increased with time, but this did not enhance growth of the operated extremity; (5) Placement of the horizontal arm of the plate near the growth cartilage of the femoral head enhanced growth of the operated extremity; (6) Enhancement of growth was greatest in children operated between 2 and 10 years of age and growth was distinguished by regular increase in length during the first 12 months from surgery; (7) Fixation of the osteotomy of the proximal femur in children may be one of the causes of enhancement of growth of the operated extremity. Early removal of the fixation device after healing of the osteotomy may arrest further growth of the extremity; (8) Coexistence of Ehlers-Danlos syndrome does not essentially influence enhancement of growth of the operated extremity.