Cox2 inhibitors decrease prostaglandin production and therefore influence bone healing especially in unstable long bone models. It is unclear to what extent implant fixation in stable metaphyseal bone is impaired. Male rats numbering 30 and female rats numbering 40 received a stainless steel screw in the metaphyseal bone of the proximal tibia. Half of the rats were treated with 6.4 mg/kg BW parecoxib by continuous release from a subcutaneous mini pump during 7 or 14 days. After treatment, the pull out force, stiffness, and pull out energy of the screw were measured. No effect of parecoxib on the pull out force was found for male rats. In female rats the pull out force was decreased by 16% (P = 0.03) after 7 days treatment with parecoxib. This effect had disappeared after 14 days. Adverse effects of parecoxib on the early phase healing of metaphyseal bone in female rats are small and were not detectable after 14 days. No effect was seen in male rats, possibly due to a faster metabolic elimination of the drug.