The effect of a nonsteroidal antiinflammatory drug on the healing of ligaments

Because of the increasing number of ligament sprains being treated with nonsteroidal antiinflammatory drugs (NSAIDs), this study was undertaken to document the effects of one such drug on ligament healing in an experimental setting. Male Sprague-Dawley rats weigh ing between 400 and 500 g were used to evaluate the effect of the NSAID piroxicam on the healing of an experimental injury to the medial collateral ligament (MCL). The following factors were varied in the experi ments: dosage, days of treatment, and the day postin jury when treatment was begun. Piroxicam-treated rats were compared to placebo-treated rats in terms of the drug's effect on the mechanical strength of the healing ligament. The ligaments were mechanically tested in tension to failure at a constant deformation rate of 0.25 mm/sec on a materials testing machine. Administration of piroxicam on Days 1 to 6 postinjury resulted in a 42% increase in strength at Day 14 postinjury for the piroxicam-treated ligaments (P < 0.01) when compared with the placebo-treated controls. Neither doubling nor halving the standard piroxicam dose significantly al tered this increased healing strength. Biochemical analysis of collagen synthesis demonstrated a sugges tive, although not statistically significant, increase in collagen synthesis and collagen content in the piroxi cam-treated healing ligament. In separate experiments, piroxicam had no effect on the healed ligament at 21 days or on the strength of uninjured ligaments. In conclusion, piroxicam increased the early strength of healing ligaments in the rat when the drug was admin istered for short periods of time after injury. It did not affect the final strength when healing was complete, nor did it alter the strength of uninjured ligaments.