Suture anchor versus screw fixation for greater tuberosity fractures of the humerus—a biomechanical study

Abstract

Suture anchors and screws are commonly used for fixation of humeral greater tuberosity (GT) fractures in either arthroscopic or open surgeries, but no biomechanical studies have been performed to compare the strength of fixation constructs using these two implants. This cadaveric study aimed to compare the biomechanical strength of three different fixation constructs in the management of GT fractures: Double-Row Suture Anchor Fixation (DR); Suture-Bridge Technique using suture anchors and knotless suture anchors (SB); and Two-Screw Fixation (TS). The experimental procedure was designed to assess fracture displacement after cyclic loading, failure load, and failure mode of the fixation construct. Significant differences were found among the SB (321 N), DR (263 N), and TS (187 N) groups (SB > DR > TS, p < 0.05) in the mean force of cyclic loading to create 3 mm displacement. Regarding the mean force of cyclic loading to create 5 mm displacement and ultimate failure load, no significant difference was found between the DR (370 N, 480 N) and SB (399 N, 493 N) groups, but both groups achieved superior results compared with the TS group (249 N, 340 N) (p < 0.05). The results suggested that the suture anchor constructs would be stronger than the fixation construct using screws for the humeral GT fracture. Keywords: humeral greater tuberosity fracture; suture anchor; screw; double-row fixation; biomechanics Isolated greater tuberosity (GT) fractures of the humerus are common. The rate of incidence is $17% to 21% among proximal humeral fractures.1 GT fractures often occur in anterior shoulder dislocation or as the result of an impaction injury. Although the amount of displacement requiring operative reduction and fixation is disputed, the consequences of an untreated malunited GT fracture can be pain and limited motion.2 Current literature recommends surgical intervention in cases with >5 mm of displacement in the general population or >3 mm of displacement in active patients. 1,[3][4][5] Open surgeries or percutaneous techniques with the aid of fluoroscopy using suture anchors or screws are well accepted for the reduction and fixation of GT fractures. 1,6,7 However, the techniques continue to evolve, particularly minimally invasive and arthroscopic techniques that have the advantages of minimizing skin incision, soft tissue dissection, and associated morbidities. 8,9 The materials used for arthroscopic fixation include suture anchors 9-13 or percutaneous screws.14,15 Although both implants are commonly used for fixation in GT fractures, mechanical stability remains a major concern for early postoperative mobilization and optimal functional results. No biomechanical studies have been performed to compare the strength of fixation constructs using suture anchors or screws. Therefore, our purpose was to analyze the strength of three different fixation constructs, using suture anchors or screws, for the management of GT fractures. We hypothesized that the suture anchor configurations would provide more biomechanica...

Locking plate fixation provides superior fixation of humerus split type greater tuberosity fractures than tension bands and double row suture bridges

“…These have excellent bone quality, which is representative of young human bone. For example, our specimens were able to withstand the loads to failure reported in previous cadaveric GT biomechanical studies (263 N and 370 N at 3 mm and 5 mm of displacement respectively for suture bridge double row fixation) (Braunstein et al, 2007;Ishak et al, 2006;Lin et al, 2012). However, it may not serve as an adequate model for older, osteoporotic bone.…”

“…Previous biomechanical studies have evaluated fixation for this splittype fracture (Braunstein et al, 2007;Ishak et al, 2006;Lin et al, 2012) and have consistently demonstrated the inferiority of screw fixation compared to Double row and tension band in terms of resistance to displacement (load at 3 and 5 mm) and load to failure. Two separate studies demonstrated the superiority of the tension band and double-row fixation techniques but no study has directly compared the two.…”

Effect of shoulder abduction on the fixation of humeral greater tuberosity fractures: a biomechanical study for three types of fixation constructs

“…5,12,16,19 A previous study compared the biomechanical strength of 3 common fixation constructs of these 2 materials and showed that constructs using suture anchors had better biomechanical strength. 22 However, no biomechanical studies have been conducted to investigate the influence of shoulder abduction position on the biomechanical properties of these 3 fixation constructs.…”

Arthroscopic Treatment of Greater Tuberosity Avulsion Fractures

“…The authors conclude that suture anchor constructs provide stronger fixation than screws for GT fractures. 17 Overall, outcomes and biomechanical studies show that arthroscopic-assisted GT fixation is a safe, effective, and reliable alternative to open fixation for fractures of the GT of the humerus. Long-term studies should be performed to assess outcomes, and comparative studies should be performed to elucidate the advantages and disadvantages of open versus arthroscopic-assisted procedures.…”

“…15 Most recently, Liao et al 16 published the largest series in the literature directly comparing arthroscopic to open fixation for GT fractures in 26 versus 53 patients, respectively; the authors found no clinically significant difference in time to union, complications, or outcomes scores between the groups. 16 Lin et al 17 compared double-row suture anchor fixation (DR), suture-bridge technique using knotless Relying on arthroscopic visualization without the addition of fluoroscopy may lead to malreduction suture anchor fixation (SB), and two-screw fixation (TS) techniques. Mean force of cyclic loading to create 3 mm of displacement was significantly different among all 3 groups (SB > DR > TS).…”