The behaviour of knots and sutures during the first 12 hours following a Bankart repair

It has been reported that the effectiveness of arthroscopic procedures in terms of preventing recurrent dislocation has not matched that from open techniques. Also little is known about how these knots behave when exposed to physiological loading following repair. This study presents the development of a practical tool to allow surgeons to test the quality of their arthroscopic knots and allow them to make choices with regard to knot configuration and suture material. This study uses an apparatus to model the repair of a Bankart lesion. Ten examples of the Duncan loop and SMC knots were tied using PDS, Ethibond, Panacryl and Fibrewire. An arthroscopic knotting technique was used. Reverse slippage occurring during the tying process was recorded. Each knot was then left for 12 hours under loads equivalent to a Bankart repair and the subsequent reverse slippage was recorded. After initial passing of the Duncan loop and after passing of locking hitches the sutures were ranked inversely to size of suture loop (resistance to slippage). Only Fibrewire showed a significant difference (5.7 +/- 1.03 mm to 5.66 +/- 0.5 mm; p <0.05). After 12 hrs, some evidence of reverse slippage was noted, especially with Fibrewire (5.66 +/- 0.5 mm--significant p <0.05). The SMC knot showed generally inferior results. In this study using arthroscopic techniques, Fibrewire performed less well than other materials.