Abstract
Background: Shortening or tightening of dense, collagenous tissues is often desirable in the treatment of laxity.
Purpose: To compare the effect of stress-protection suture, radiofrequency thermal shrinkage combined with stress-protection suture, and a 5% sodium morrhuate sclerosing injection on the length and biomechanical strength of the rat patellar tendon.
Hypothesis: Sclerosing agents will increase tendon mechanical strength. Thermal shrinkage combined with stress-protection suture and stress-protection suture only will cause a short-term decrease in tendon strength. All 3 methods will produce equivalent shortening of the tendon.
Study Design: Controlled laboratory study.
Methods: Forty-six female retired breeder rats were split into 4 groups, each receiving 1 of the 3 aforementioned treatments plus a control group that received a saline injection. After 4 weeks’ survival, the length and biomechanical properties of the patellar tendons were measured and compared to the contralateral untreated tendon.
Results: Rats treated with stress-protection suture had shorter tendons. Radiofrequency thermal shrinkage combined with stress-protection suture yielded tendons that were both shorter and stronger than were the untreated contralateral tendons. The sodium morrhuate-injected tendons were stronger whereas the saline-treated tendons were weaker than were their respective untreated contralateral tendons.
Conclusion: Surgical stress-protection suture without radiofrequency shrinkage is most effective at shortening the length of the rat patellar tendon, whereas radiofrequency thermal shrinkage combined with stress-protection suture as well as sodium morrhuate are effective at increasing the strength of rat patellar tendons.
Clinical Relevance: Judicious use of thermal shrinkage in combination with stress protection may improve ligament strength and decrease laxity.
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