EFFECT OF 2 NONSTEROIDAL ANTIINFLAMMATORY DRUGS ON HETEROTOPIC BONE-FORMATION IN A RABBIT MODEL

Using the model described by Michelsson, 24 mature New Zealand white r abbits underwent mechanical induction of heterotopic ossification in t he quadriceps of the right hind limb. The rabbits were equally divided into four groups: indomethacin-treated, piroxicam-treated, and their respective controls. The effect of drug therapy on the production of h eterotopic bone was assessed by analyzing plain radiographs of the fem ur using the grading system described by Scott. The results demonstrat ed that, while indomethacin is effective in decreasing the formation o f heterotopic bone, piroxicam - when used in the dosage previously dem onstrated to have no deleterious effect on healing bone - is not. The analysis of piroxicam blood levels demonstrated that the experimental piroxicam dose is inadequate to produce effective plasma blood levels in the rabbit. Therefore, any potential benefit from using piroxicam, as opposed to other nonsteroidal antiinflammatory drugs regarding frac ture healing and bone remodeling, cannot be applied for the prophylact ic treatment of heterotopic bone formation.