The "double-barrel" knot: a new sliding knot for arthroscopic soft tissue fixation using single-pulley and double-pulley techniques

A biomechanical comparison of different tying techniques of a double-stranded looped suture

PURPOSE

This study aims to assess the biomechanical performance of different tying techniques of a double-stranded looped suture (DSLS).

METHODS

Loop and knot security of DSLS tying techniques (nice knot (NK), modified nice knot (MNK), double-twist knot (DTK), and double-barrel knot (DBK)) were compared. The square knot of DSLS (SKD) and the square knot of single-stranded suture (SKS) had been used as references. Twenty-four loops of each configuration were created using No. 2 Fiberwire (Arthrex, Naples, Florida, USA) and tested with a material testing machine. Samples were loaded with 10 N preloads for loop security assessment. Knot security was subsequently evaluated. Twelve loops of each knot were loaded to failure. The rest were subjected to cyclic load testing and the elongation at the 50th and 1000th cycles were measured. Knot bulkiness was determined by measuring knot height before testing. Data were compared with analysis of variance and post hoc tests. Statistical significance was p < 0.05.

RESULTS

All knots showed no statistically significant difference in displacement with preload. The load-to-failure was highest in NK, followed by MNK, DTK, DBK, SKD, and SKS. The cyclic loading test at the 50th cycle and the 1000th cycle demonstrated that NK has significantly less displacement than the others except MNK. DTK provided a minimal average knot height followed by NK, SKS, DBK, MNK, and SKD.

CONCLUSION

The different tying techniques in DSLS provided the similar loop security but different knot security and knot bulkiness. NK and MNK are biomechanically superior to the other knots, whereas DTK is the least bulky. The findings in the present study may help set the guide for the surgeons to select the tying technique of DSLS to best suit their requirement.

Double-Barrel Remplissage: An Arthroscopic All-Intra-articular Technique Using the Double-Barrel Knot for Anterior Shoulder Instability

The arthroscopic remplissage procedure is an effective addition to a standard anterior repair in traumatic anterior shoulder instability associated with large humeral defects. The double-barrel remplissage is an all-intra-articular technique that uses a double-pulley, sliding, and self-retaining knot mechanism called the double-barrel knot. A 70° arthroscope (posterior portal) is necessary for adequate visualization of the humeral defect and the rotator cuff. Trans-tendon anchors (single or double loaded) are inserted into the superior and inferior aspects of the humeral defect through a cannula that is placed posterior to the infraspinatus. Placement of anchors is facilitated by insertion of a guidewire, as well as an anchor sleeve that is threaded over it. The double-barrel knot is formed using the anchors as a double-pulley system, and the knot is tensioned after the anterior repair is complete. Intra-articular visualization confirms adequate approximation and compression of the infraspinatus tendon and capsule into the defect. Advantages include an increased surface area (footprint) for healing and ease of knotting without the necessity for additional subacromial dissection.

Arthroscopic Latarjet and Capsular Shift (ALCS) procedure: a new "freehand" technique for anterior shoulder instability associated with significant bone defects

Anterior shoulder instability associated with significant bone loss has been described as "bony-instability," and this condition is usually treated with an anterior glenoid bone grafting procedure (Latarjet procedure). The Latarjet procedure involves transfer of the horizontal limb of the coracoid process along with the conjoint tendon to the anterior glenoid rim, and is traditionally performed as an open surgical procedure. Recently, an arthroscopic technique for the Latarjet procedure has been described; the technique necessitates the use of specialized instrumentation and involves excision of the entire anterior capsule to facilitate coracoid fixation. We describe a new "freehand" arthroscopic technique for the Latarjet procedure, and, in addition, a simultaneous capsular shift to further optimize mid and end range stability. This technique eliminates the use of additional instrumentation and can be done using routine arthroscopic instruments. Preliminary experience with this technique suggests that the arthroscopic Latarjet and capsular shift is a technically demanding procedure. Glenohumeral capsule can be preserved, and this should be attempted wherever possible to optimize stability. Additional specialized instrumentation would probably reduce surgical time; however, the procedure can be performed with routine instruments.