The use of nonsteroidal anti-inflammatory drugs (NSAIDs) continues to expand at a remarkable rate due both to their broad spectrum clinical applications. NSAIDs are particularly important to patients with a variety of musculoskeletal conditions and injuries. With mounting evidence that NSAIDs do in fact interfere with proper bone healing in various animal models, questions have arisen regarding the differences between the short-and long-term treatments with these drugs on fracture healing, in addition to, the effect of their combined treatment.
Left tibias of 42 male rabbits were fractured by manual pressure under general anaesthesia and are stabilised by Zimmer plate. These animals are divided into seven groups; 6 rabbits each: group (1), control group, given normal saline; group (2), given aspirin (25mg/kg/day) for 2 days post-fracture; group (3), given aspirin for 14 days post-fracture; group (4), given diclofenac (2.5mg/kg/day) for 2 days post-fracture; group (5), given diclofenac for 14 days post-fracture; group (6), given aspirin and diclofenac for 2 days post-fracture; and group (7), given aspirin and diclofenac for 14 days post-fracture. Drugs were administered intramuscularly.
All animals were sacrified 21 days after fracture. At this time, evaluation of fracture healing was performed blindly by two radiologists and a histologist according to a 5- point scale of a descriptive assessment and scores of each group were compared with control and other groups. Both aspirin and diclofenac, when given indivdually for 14 days, produced a statistically significant inhibitory effect on fracture healing, but they have no significant effect when given for 2 days. Administration of aspirin and diclofenac together had a significant delaying effect on fracture healing even after short duration (2 days). The latter effect appeared mainly in histological examinatiom indicating that histological methods of assessment may be more valuable than radiological ones.
It is, therefore, concluded that aspirin and diclofenac should cautiously be used during fracture healing; firstly, they should be given for the shortest possible duration and secondly, should not be given in combination.