Bone healing during lower limb lengthening by distraction epiphysiolysis.

A study of limb lengthening by distraction epiphysiolysis in the rabbit tibia is presented. A special external distraction device was developed that allowed 10 mm lengthening of the leg. Bone formation in the elongated zone was studied by computed tomography and [99mTc] methylene diphosphonate (MDP) scintigraphy. Computed tomography showed bone formation proceeding for several weeks after the end of the distraction period, followed by a decrease in the amount of bone during a remodeling phase leading to the formation of a solid cortical structure. The uptake of [99mTc]MDP increased parallel to, but preceeding the actual accretion of bone, followed by a decrease during the bone remodeling phase. Uptake of the tracer will partly reflect bone metabolism, but other factors, like trauma, determine much of the uptake.