Effects of shock waves on the structure and growth of the immature rat epiphysis.

The left proximal tibia of eighteen five week old male Sprague-Dawley rats was exposed to 1500 shock waves at 20 kV in a Dornier XL-1 experimental lithotripter. Six of these rats, and six age-matched controls, were sacrificed two, four and ten weeks later. Eight of 18 (44%) of treated animals had lesions of focal growth plate dysplasia attributable to treatment. In the absence of extensive lesions, no significant difference was identified in the growth plate thickness of shocked versus unshocked limbs. In the group sacrificed at ten weeks, two of six (33%) treated animals had extensive dysplastic lesions which were associated with marked shortening of the shocked limb. In the absence of extensive lesions, there was no significant shortening of shocked limbs. Shock wave exposure of the rat epiphysis can affect subsequent bone growth.