Chih-Kai Hong

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

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.

Hamstring Graft Preparation Using a Modified Rolling Hitch Technique

Anterior cruciate ligament reconstruction using double-looped hamstring autograft is a common procedure in orthopaedic practice. However, during placement of the running, locking stitches at each end of the harvested tendons, the surgeon may face several potential obstacles, including the risk of damaging the tendon, predisposing the surgeon to needle-stick injury, and extended time consumption. We report a modified rolling hitch technique for hamstring graft preparation that is quick, cost-saving, and needleless as an alternative method. The original rolling hitch technique uses a traditional knot that attaches a rope to an object; the modified rolling hitch technique was created by adding 1 more turn before finishing with a half-hitch, which may prevent suture slippage off the tendon, thus providing sufficient fixation of the suture-tendon construct.

Do Needleless Knots have Similar Strength as the Krackow Suture? An In Vitro Porcine Tendon Study

BackgroundNumerous needleless techniques for tendon graft fixation that feature several advantages have been reported. However, there are few studies that have compared the holding strength between the needleless techniques (rolling hitch and modified rolling hitch) and traditional suture methods.Questions/purposesTo compare the tendon graft-holding strength of the rolling hitch and modified rolling hitch with the Krackow stitch in an in vitro porcine biomechanical model.MethodsThirty fresh-frozen porcine flexor profundus tendons were randomly divided into three groups of 10 specimens. The experimental procedure was designed to assess elongation of the suture-tendon construct across the needleless tendon-grasping techniques and the Krackow stitch. All suture configurations were completed with a braided nonabsorbable suture. Each tendon was pretensioned to 100 N for three cycles, cyclically loaded from 50 to 200 N for 200 cycles, and then finally loaded to failure. Elongation, load to failure, and mode of failure were recorded for each specimen.ResultsFive of the 10 rolling hitch specimens failed during cyclic loading. With the numbers available, elongation after cyclic loading was not different among the successful rolling hitch specimens (19% [1.19 cm/6.17 cm] ± 6%), modified rolling hitch fixations (19% [1.11 cm/ 5.93 cm] ± 6%), and Krackow stitch fixations (26% [1.41 cm/5.43 cm] ± 6%); ultimate failure loads also were not different among the rolling hitch fixations (316 ± 35 N), modified rolling hitch fixations (342 ± 14 N), and Krackow stitches (327 ± 33 N) with the numbers available.ConclusionsWith the numbers available, the rolling hitch, modified rolling hitch, and Krackow stitch techniques were not different in terms of elongation after cyclic loading and to failure in this in vitro biomechanical evaluation.Clinical RelevanceBased on the biomechanical properties from this in vitro animal study, the modified rolling hitch may be an attractive alternative for tendon graft fixation in ligament-reconstruction surgery. Future studies might consider further evaluating these needleless techniques in a cadaver model, in an in vivo animal model, and in an intraarticular model in which the testing is performed in the presence of synovial fluid.

An Arthroscopic Technique for Long Head of Biceps Tenodesis With Double Knotless Screw

Tenodesis of the long head of the biceps (LHB) is a frequently performed procedure during shoulder arthroscopy for the treatment of degenerative, traumatic, or inflammatory lesions of the LHB tendon. Arthroscopic techniques for LHB tenodesis using knotless screw techniques offer the advantage of circumventing the need for arthroscopic knot tying. In 2012 Song and Williams described a novel tenodesis technique that does not require any knot-tying procedures by using a knotless anchor. However, a single-anchor configuration may not offer adequate stabilization of the LHB tendon. Therefore we propose a modified method that uses a double knotless anchor that offers advantages over the single knotless anchor, such as an increase in the contact area between the tendon and bone to facilitate tendon-to-bone healing and strengthening of the tenodesis construct.

Arthroscopic Transtendinous Biceps Tenodesis With All-Suture Anchor

There are several methods for long head of the biceps (LHB) tenodesis, yet the optimal option is still debatable. Here we introduce a technique for arthroscopic suprapectoral biceps tenodesis with an all-suture anchor, the transtendinous biceps tenodesis technique. The LHB tenodesis is performed by using the Y-Knot anchor (1.3-mm). A standard suprapectoral approach is used for the tenodesis. A 1.3-mm drill bit is used to drill through the midportion of the biceps tendon and underlying bone to make a pilot hole. Next, the Y-Knot anchor is passed through the tendon and anchored on the underlying bone. A wrapping suture technique is then used to wrap around, tension, and secure the LHB tendon with the aid of a shuttling polydioxanone suture. The construct is fixed by tying down both suture limbs in a nonsliding fashion. This Technical Note describes an alternative method for all-arthroscopic suprapectoral biceps tenodesis using an all-suture anchor with a small diameter to minimize trauma to the tendon.

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

BACKGROUND An abduction brace and abduction exercises are commonly employed after humeral greater tuberosity fracture repair. However, the effects of glenohumeral abduction on the biomechanical strength have seldom been elucidated. METHOD We studied 24 pairs of female fresh frozen porcine shoulders randomly divided into 3 groups. After creation of a greater tuberosity fracture on each shoulder, 3 fixation techniques were used for the 3 groups: double-row suture anchor fixation (DR), suture bridge technique (SB), and 2-screw fixation (TS). This biomechanical study was conducted to compare the forces that create 3- and 5-mm displacements and the ultimate failure load at the simulated shoulder abduction angles of 0° and 45° among the 3 groups. RESULTS In the DR group, the mean forces to create 3- and 5-mm displacements and the failure load at 0° were higher than those at 45° (P = .036, P = .012, P = .027). By contrast, in the SB group, the mean forces to create 3- and 5-mm displacements at 45° were greater than those at 0° (P = .012, P = .012). There were no significant differences in the forces to create 3- and 5-mm displacements and construct failure between 0° and 45° in the TS group (P = .575, .327, .478). CONCLUSION The DR group had greatest initial fixation strength at a low abduction angle, whereas the SB group had the highest initial fixation strength at a high abduction angle. The TS group appeared unaffected by the abduction angle.

Longer stitch interval in the Krackow stitch for tendon graft fixation leads to poorer biomechanical property

Purpose: The purpose of this study was to analyze the effects of different intervals between stitch throws on tendon graft fixation with the Krackow stitch. Methods: Forty-four porcine flexor profundus tendons were randomly divided into four groups of 11 specimens each. The Krackow stitch with various stitch intervals (2.5, 5.0, 7.5, and 10.0 mm) were evaluated, and named the K-2.5, K-5.0, K-7.5, and K-10.0 groups, respectively. A braided nonabsorbable suture was used to complete each suture-tendon construct. All specimens were pretensioned to 100 N for three cycles, cyclically loaded from 50 to 200 N for 200 cycles, and then finally loaded to failure. Elongation after cyclic loading, ultimate load to failure, and the mode of failure were recorded. Results: There were significant differences in elongation after cyclic loading among the K-2.5 (31% ± 5%), K-5.0 (32% ± 4%), K-7.5 (34% ± 5%), and K-10.0 (41% ± 8%) groups (p = 0.004); the post hoc analysis showed significantly smaller values in the K-2.5 and K-5.0 groups than in the K-10.0 group (p = 0.002 and 0.003, respectively). The stitch interval was correlated with elongation after cyclic loading (r = 0.52, p < 0.001). Ultimate loads to failure and cross-sectional area were not significantly different across the four groups. Conclusion: The Krackow stitch with stitch intervals of 2.5 and 5.0 mm had significantly smaller elongation after cyclic loading than with an interval of 10.0 mm in this porcine biomechanical study. The stitch interval was moderately correlated with elongation after cyclic loading.

The relationship of the anterior articular capsule to the adjacent subscapularis: An anatomic and histological study

INTRODUCTION The purpose of this study was to delineate the anatomic relationship between the anterior articular capsule and the adjacent subscapularis by measuring the dimensions of the anterior articular capsule attachment and the subscapularis footprint on the humerus, as well as investigating the interface between the two structures. MATERIALS AND METHODS Three shoulder specimens underwent histological analysis; for histological analysis, cross-sections through the subscapularis-capsule complex were harvested at the tendinous and muscular insertion sites. The dimensions of the anterior articular capsule attachment and the subscapularis footprint (including the tendinous and muscular insertions) were measured in thirteen cadaveric shoulder specimens. RESULTS Histologically, the articular capsule has thin and loosely arranged collagen fibers with many interspersing fibroblast nuclei, whereas the outer layer of the articular capsule blends into a layer of more loosely spaced and less organized collagen fibers. This interface between the subscapularis and the underlying articular capsule is filled with more loosely spaced and less organized collagen fibers. The macroscopic evaluation showed that the minimum articular capsule width (4.2mm, SD 2.2mm) was located at its initiation 4.9mm (SD, 2.1mm) inferior to the superior margin of the subscapularis; the corresponding subscapularis footprint width measured 10.1mm (SD, 4.9mm). The maximum articular capsule width was11.1 mm (SD, 3.7mm) and was located 5mm distal to the inferior margin of the tendinous footprint. The maximum subscapularis footprint width was 15.8mm (SD, 2.9mm); the corresponding articular capsule attachment measured 5.2mm (SD, 1.8mm). CONCLUSIONS Our results suggest that the anterior articular capsule attachment of the glenohumeral joint complements the footprint of the subscapularis and occupies a larger area of the lesser tubercle and metaphysis of the humerus than previously documented. The histological study confirms the presence of a demarcation between the subscapularis and articular capsule, specifically more significant at the region medial to the tendon insertion and at the muscular insertion of the subscapularis.

Rapid progression and mortality of necrotizing fasciitis caused by Aeromonas hydrophila in a patient with type I open tibial fracture

Posttraumatic infections frequently occur in patients with contaminated open fractures, especially in patients with underlying medical conditions contributing to the compromised immunity [1]. Necrotizing fasciitis is a severe but rare infectious process that is characterized by rapid, widespread necrosis of the skin, subcutaneous tissue, and superficial fascia [2]. Herein, we report a rare case of necrotizing fasciitis that caused mortality in a short time in a middle-aged patient with a type I open tibial shaft fracture. This report aims to remind clinical physicians to be aware of possible necrotizing fasciitis when dealing with open fractures. The patient was a 42-year-old man with alcoholic liver cirrhosis. He did not have hypertension, diabetes mellitus, or any immunocompromised disease. His baseline liver and renal functions were normal. He incurred a right tibiaefibula open shaft fracture, Gustilo type I, occurred after a fall (Fig. 1AeC). Precise history of the patient could not be obtained because the patient was drunk at the time of injury. A 1-cm open wound and superficial abrasions were found upon initial evaluation. In the emergency department, we irrigated the wound with 3000 ml of normal saline and covered the wound appropriately. Empirical antibiotics, cefazolin plus gentamicin, were administered. A few hours later, the patient underwent the surgery, debridement of the open wound, and open reduction and internal fixation with a tibial interlocking nail for the tibial shaft fracture (Fig. 1DeE). His consciousness changed and he developed hypotension on postoperative day 1. Chest computed tomography (CT) with contrast was performed and ruled out the presence of a massive pulmonary embolism. Diffuse liver cirrhosis was observed on CT. The patient

Augmentation by cerclage wire improves fixation of vertical shear femoral neck fractures—A biomechanical analysis

BACKGROUND Femoral neck fractures in young individuals are typically vertical shear fractures. These injuries are difficult to stabilize due to a significant varus displacement force across the hip with weight bearing. The purpose of this study was to evaluate the biomechanical stability offered by the addition of an augmented wire to conventional inverted triangle triple screw fixation for stabilizing vertical shear femoral neck fracture. METHODS Sixteen medium 4th-generation synthetic composite femurs (Sawbones Pacific Research Laboratories, Vashon, WA) were divided into two groups. Vertical osteotomy was performed to mimic Pauwels III femoral neck fracture. Group A (n=8) was fixed with three parallel 6.5-mm cannulated screws (Stryker) with washer in inverted triangle configuration. In group B (n=8), all the screws were set using methods identical to group A, with the addition of the cerclage wire. Both groups were tested with nondestructive axial compression test at 7 and 25° of valgus stress, respectively. Then axial cyclic loading test with 1000N was applied for 1000 cycles, and interfragmentary displacement was measured with Fastrak magnetic tracking system (Polhemus, Colchester, VT, USA). Finally, destructive axial compression test was conducted at 7°of valgus stress. RESULTS Axial stiffness showed that group B had a 66% increase (879N/mm vs. 1461N/mm, P<0.01) at 7° valgus and a 46% increase (1611N/mm vs. 2349N/mm, P<0.01) at 25° valgus in comparison with group A. Interfragmentary fracture displacement after cyclic loading was significantly less for group B compared with group A (0.34 vs 0.13mm, P=0.0016). For axial failure load, there was 42% increase in group B compared with group A (2602N/mm vs. 3686N/mm, P=0.0023). CONCLUSIONS Our study demonstrates that the addition of a cerclage wire to inverted triangle triple screws provides substantial improvement in mechanical performance regarding fixation of vertically oriented femoral neck fractures when compared with the conventional construct. Our study provides support from a mechanical analysis perspective for the reported clinical usefulness of the cerclage wire.