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 swelling because of edema and hemorrhage, as well as progressive, often permanent joint stiffness. The authors evaluated the effects of chlorothiazide, a commonly used diuretic, and acetazolamide, a weaker diuretic with a different mechanism of action, on joint stiffness and swelling using an established rabbit hindlimb model. Bilateral distal tibial fractures were produced in 30 adolescent New Zealand white rabbits. Twelve rabbits served as age-matched controls and received no treatment, 11 were treated with chlorothiazide, and seven were treated with acetazolamide, each for five days at doses adjusted for body weight but equivalent to human dosing. Eleven limbs were excluded from study because of fracture angulation in excess of 10 degrees. The mean stiffness ratios, comparing preoperative stiffness with stiffness at the end of the three-week study period, for diuretic-treated rabbits were significantly less than those in the control rabbits; there was no difference between the two treated groups. The total swelling and time to peak swelling 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 diuretics on joint stiffness and their minimal effect on limb swelling were unexpected results and, taken in conjunction with previous treatment modalities tested in this model, indicate a complex, still poorly understood sequence of events leading to joint stiffness after periarticular injury.