Mechanical Effects of Heat Exposure From a Bipolar Radiofrequency Probe on Suture Under Simulated Arthroscopic Conditions.

Purpose: To determine conditions for the safe use of radiofrequency (RF) tissue ablation probes that avoid damaging suture material.

Methods: Four sutures made of 3 different materials commonly used in arthroscopic procedures were analyzed in a saline bath related to effects of RF-produced heat by proximity, duration, and intensity settings measuring burn-through time and ultimate load to failure. The parameters tested were electrode-to-suture distance, power setting, and the presence of tendon tissue or metallic anchor eyelets. Outcome variables were the burn-through time and the ultimate failure load of differently treated suture samples.

Results: Mean burn-through time for suture in direct contact with the RF probe ranged from 57.2 to 14.7 seconds for ultra-high-molecular-weight polyethylene (UHMWPE) sutures, 1.1 seconds for polydioxanone suture, and 0.8 seconds for polyethylene terephthalate suture. One of the UHMWPE sutures was capable of withstanding 3 seconds of direct contact with the RF probe without any compromise in tensile strength. No suture material tested had any mechanical change as long as the RF probe was kept 1 mm from the suture.

Conclusions: Heat from RF tissue ablation probes can cause undetected damage. High-strength UHMWPE sutures were less sensitive to an RF treatment than polyester sutures. The use of different test substrates did not significantly influence the burn through time.

Clinical Relevance: Heat from RF probes can damage some suture material if direct contact is made even briefly. The use of RF devices may be safe for the suture when a distance between probe and suture of >1 mm is maintained. Suture made from UHMWPE may tolerate up to 3 seconds of RF probe contact and not sustain significant damage. Surgeons must use great care when using RF devices in the vicinity of suture placement.