Biomechanical Characterization of a New Locking Loop Stitch for Graft Fixation versus Krackow Stitch.

Background: The purpose of this study was to quantify and compare the biomechanical characteristics of a new locking loop stitch (LLS), developed utilizing the concepts of both running locking stitch and needleless stitch, to the traditional Krackow stitch. Methods: The Krackow stitch with No.2 braided suture and the LLS with 1.3-mm augmented polyblend suture tape were compared biomechanically. The LLS was performed with single strand locking loops and wrapping suture around the tendon, resulting in half the needle penetrations through the graft compared to the Krackow stitch. Twenty bovine extensor tendons were divided randomly into two groups. The tendons were prepared to match equal thickness and cross-sectional area. Each suture-tendon was stitched and preloaded to 5 N for 60 seconds, cyclically loaded to 20 N, 40 N, and 60 N for 10 cycles each, and then loaded to failure. The deformation of the suture-tendon construct, stiffness, yield load, and ultimate load were measured. Results: The LLS had significantly less deformation of the suture-tendon construct at 100 N, 200 N, 300 N, and at ultimate load compared to the Krackow stitch (Krackow stitch and LLS at 100 N: 1.3 ± 0.1 mm and 1.0 ± 0.2 mm, p < 0.001; 200 N: 3.0 ± 0.3 mm and 1.9 ± 0.2 mm, p < 0.001; 300 N: 5.1 ± 0.6 mm and 2.9 ± 0.4 mm, p < 0.001; ultimate load: 12.8 ± 2.8 mm and 5.0 ± 1.2 mm, p < 0.001). The LLS had significantly greater stiffness (Krackow stitch and LLS: 97.5 ± 6.9 N/mm and 117.2 ± 13.9 N/mm, p < 0.001) and yield load (Krackow stitch and LLS: 66.2 ± 15.9 N and 237.9 ± 93.6 N, p < 0.001) compared to the Krackow stitch. There was no significant difference in ultimate load (Krackow stitch: 450.2 ± 49.4 N; LLS: 472.6 ± 59.8 N; p = 0.290). Conclusions: The LLS had significantly smaller deformation of the suture-tendon construct compared to the Krackow stitch. The LLS may be a viable surgical alternative to the Krackow stitch for graft fixation when secure fixation is necessary.

Shoulder surgeon techniques and preferences in treatment of massive rotator cuff tears: current practices for rotator cuff repair and superior capsule reconstruction.

Background: Massive rotator cuff tears can be difficult to manage and consensus regarding treatment is debated. The purpose of this questionnaire study was to examine surgeon techniques and considerations for treatment of massive rotator cuff tears including how they implement superior capsule reconstruction (SCR), when indicated. Methods: A 21-item questionnaire was sent to members of the American Shoulder and Elbow Surgeons and the American Orthopedic Society for Sports Medicine. Questions covered management preferences for massive rotator cuff tears, rotator cuff repair and SCR techniques, beliefs about SCR, implant choices, use of augments, demographics, and patient management scenarios. Results: The questionnaire had 230 respondents. In rotator cuff repair of massive rotator cuff tears, preferred responses were long head biceps tendon preservation (when asymptomatic, 45.3%), routine subacromial decompression (62.1%), solid threaded anchors (71.1%), double row configuration (65.1%), and bone marrow stimulation of the footprint (55.6%). For providers that perform SCR (n = 166), preferred strategies included long head biceps tenodesis (55.4%), human dermal allograft tissue (93.2%), glenoid fixation with 3 implants (71.2%) using solid threaded anchors (42.3%), and humeral fixation with 2 solid threaded anchors medially (71.0%), and 2 solid threaded anchors laterally (46.9%). Other highly recommended strategies were side-to-side repair to the posterior rotator cuff if able (97.6%) and to use the thickest graft available (62.2%). Conclusion: Despite improved techniques and growing interest in SCR, many questions still remain. This study identifies the significant variability in repair constructs and methodology with SCR; further investigation into these variables could be analyzed to identify best practice guidelines.

Biomechanical Comparison of 3 Glenoid-Side Fixation Techniques for Superior Capsular Reconstruction.

BACKGROUND: Superior capsular reconstruction (SCR) was recently introduced as a treatment for irreparable superior rotator cuff tears in younger patients. Purpose/Hypothesis: The purpose was to assess the biomechanical strength of 3 methods for fixation of the graft to the glenoid for SCR. It was hypothesized that a 4-anchor technique would provide greater load to failure than 3-anchor techniques. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty-six cadaveric specimens were randomized into 3 groups of previously established glenoid-side graft fixation techniques: (1) three 3.5-mm knotless screw-in anchors, (2) three 3.0-mm knotless push-in anchors, and (3) a 4-anchor hybrid construct with two 3.0-mm knotted push-in anchors and two 2.9-mm knotless push-in anchors. The repairs were cyclically loaded at 0.5 Hz from 10 to 200 N, then pulled to failure. Elongation, stiffness, maximum load at failure, and mode of failure were recorded and calculated. RESULTS: There were no significant differences in graft elongation or stiffness among the 3 techniques ( P > .37 and P > .26, respectively). Maximum load to failure was significantly greater in technique 1 (mean ± SD, 427.85 ± 119.70 N) than technique 3 (319.5 ± 57.60 N) ( P = 0.024). There were no significant differences in load to failure between techniques 1 and 2 or between techniques 2 and 3. CONCLUSION: Glenoid-side graft fixation with 3 threaded 3.5-mm suture anchors showed a significant superior pull-out strength when compared with a 4-anchor hybrid technique and thus might be recommended in SCR for patients with irreparable superior rotator cuff tears to achieve maximum stability. CLINICAL RELEVANCE: SCR presents a novel alternative for treatment of irreparable superior rotator cuff tears in younger patients. Glenoid fixation is essential to provide adequate fixation of the graft to prevent the humeral head from rising and to restore normal biomechanics.