THE EFFECTS OF DIURETICS ON POSTTRAUMATIC JOINT STIFFNESS AND LIMB SWELLING IN A RABBIT PERIARTICULAR FRACTURE MODEL

Periarticular long bone fractures usually result in soft-tissue swelli ng because of edema and hemorrhage, as well as progressive, often perm anent joint stiffness. The authors evaluated the effects of chlorothia zide, a commonly used diuretic, and acetazolamide, a weaker diuretic w ith a different mechanism of action, on joint stiffness and swelling u sing an established rabbit hindlimb model. Bilateral distal tibial fra ctures were produced in 30 adolescent New Zealand white rabbits. Twelv e rabbits served as age-matched controls and received no treatment, 11 were treated with chlorothiazide, and seven were treated with acetazo lamide, each for five days at doses adjusted for body weight but equiv alent to human dosing. Eleven limbs were excluded from study because o f fracture angulation in excess of 10 degrees. The mean stiffness rati os, comparing preoperative stiffness with stiffness at the end of the three-week study period, for diuretic-treated rabbits were significant ly less than those in the control rabbits; there was no difference bet ween the two treated groups. The total swelling and time to peak swell ing did not differ among the three groups; however, peak swelling was least in the chlorothiazide group, the strong diuretic, when compared with the control and acetazolamide groups. The marked effect of diuret ics on joint stiffness and their minimal effect on limb swelling were unexpected results and, taken in conjunction with previous treatment m odalities tested in this model, indicate a complex, still poorly under stood sequence of events leading to joint stiffness after periarticula r injury.