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Purpose The present study tested and compared the biomechanical properties of four different triplicate graft tendon techniques. Methods 32 tripled tendons from the common extensor muscle of bovine fingers were tested on a material testing machine, passing the end loop over a metal rod of a clevis connected to the load cell on the upper side, and fixing the lower end to a clamp. The samples were divided into four groups: (A) tripled with a free end sutured only to one of the two fixed bundles (B) tripled with a free end positioned between the two fixed strands and sutured to both (C) tripled with an S-shape and all the three strands sutured together at the upper and lower extremities of the graft (D) partially quadrupled with the free end sutured together with the other three bundles at the upper extremity. Each sample was pretensioned at 50 N for 10 min and then subjected to 1000 load control cycles between 50 and 250 N. Finally, each sample was subjected to a load to failure test. Authors also present some preliminary results on the feasibility of a non-contact and full-field Thermoelastic Stress Analysis technique, based on Infrared Thermography, to evaluate the level of stress on the whole graft, and hence on each strand, during fatigue loading. Results Eighty five percent of the samples failed at the level of the clamp. The cyclical elongation progressively decreased in all the samples and there was a simultaneous increase in stiffness. An increased stiffness was noted between Group 2 vs Group 3 and Group 2 vs Group 4 at the 500th and 1000th cycle. The failure loads were as follows: (a) 569.10 N, (b) 632.28 N, (c) 571.68 N, (d) 616.95 N. None of the parameters showed a statistically significant difference between the four groups. Conclusion This study reported similar biomechanical behavior of four different models of tripled grafts suitable for ACL reconstruction. In addition, the biomechanics of overall tripled tendon grafts seems more affected by the viscoelastic property of the tendon itself rather than the preparation method.

Purpose. This study aimed to compare the biomechanical proprieties of 4 and 5-strand- grafts. Methods. For the present study, fresh-frozen bovine common digital extensor tendons were used. Tendon grafts were prepared and sized to have a length of almost 27 cm and a cylinder 4 strand diameter of 8 mm. In half of all samples (Group A, n=12,), the graft was formed by 2 bundles duplicated around a metallic rod creating a 4-strand-tendon construct. In the other half of samples (Group B, n= 12,) 5-strand-tendon construct was created duplicating a single tendon around the rod, and tripling the other one. The grafts were preconditioned at 50 N for 10 min, followed by 1,000 cyclic loading between 50 and 250 N. Load-to-failure test was then carried out at a rate of 1 mm/s. Results. No statistically significant differences were found between two groups concern- ing cyclic elongation at the 500th cycle and at the final cycle. An increased stiffness was observed in the Group B during cyclic loads and at pull-out (p

Background Cement augmentation of internal fixation of hip fracture has reported to improve fracture stability in osteoporotic hip fractures, reducing the risk of cut-out of the sliding screw through the femoral head. The purpose of present study was to perform a systematic literature review on the effects of augmentation technique in patients with osteoporotic hip fractures. Material and methods A comprehensive literature search was systematically performed to evaluate all papers published in English language included in the literature between January 2010 and July 2020, according to the PRISMA 2009 guidelines. In vivo and in vitro studies, case reports, review articles, cadaveric studies, biomechanical studies, histological studies, oncological studies, technical notes, studies dealing with radiological classifications and studies on revision surgery were excluded. Results A total of 5 studies involving 301 patients were included. Patients had a mean age of 84.6 years and were followed up for a mean period of 11 months. The proximal femoral fractures were stabilized with implantation of the PFNA or Gamma nail and augmentation was performed with two different cements: polymethylmethacrylate (PMMA) in 4 studies and calcium phosphate (CP) in one study. Overall, 57.5% of patients reached the same or greater preoperative mobility, and postoperative Parker Mobility Score and Harris Hip Score were acceptable. No significantly complications were observed, and no additional surgery related to the implant was required. Conclusion The results of this systematic review show that cement augmentation is a safe and effectiveness method of fixation to treat trochanteric fractures.

The aim of the present study was to compare the biomechanical characteristics of posterior meniscal root repair of porcine and human menisci. Methods. In vitro biomechanical testing was performed using 12 porcine menisci and 12 human menisci. All menisci were sectioned at the midpoint of their circumference and mounted on an electro-mechanic testing machine. The posterior root was sutured with three single stitches using a no. 2 non-absorbable suture. All specimens were subjected to cyclic axial loading followed by load-to-failure testing. Displacements were recorded at the conclusion of cycles 1, 100, 500 and 1000. Further, load-displacement curves of each specimen were recorded and analyzed to determine the cyclic stiffness at the 500th and 1000th cycle. Results. A higher elongation of the human specimens was observed after 1, 100, 500 and 1000 loading cycles, when it was compared to porcine specimens (p < 0.05). The total displacement amount of the porcine specimens at the 1000th cycle was 2.2 mm +/- 0.1. Similarly, the total displacement amount of the human specimens at the 1000th cycle was 3 mm +/- 0.5. Higher stiffness was observed in the porcine group at the 500th and 1000th cycle. Conclusion. Three single sutures technique for meniscal root repair appears to be biomechanically effective for both human and porcine menisci.