Browsing by Author "Guzmán-Venegas, Rodrigo"
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Item Biomechanical Cadaveric Evaluation of Partial Acute Peroneal Tendon Tears(2018) Wagner, Emilio; Wagner, Pablo; Ortiz, Cristian; Radkievich, Rubén; Palma, Felipe; Guzmán-Venegas, RodrigoBackground: No clear guideline or solid evidence exists for peroneal tendon tears to determine when to repair, resect, or perform a tenodesis on the damaged tendon. The objective of this study was to analyze the mechanical behavior of cadaveric peroneal tendons artificially damaged and tested in a cyclic and failure mode. The hypothesis was that no failure would be observed in the cyclic phase. Methods: Eight cadaveric long leg specimens were tested on a specially designed frame. A longitudinal full thickness tendon defect was created, 3 cm in length, behind the tip of the fibula, compromising 66% of the visible width of the peroneal tendons. Cyclic testing was initially performed between 50 and 200 N, followed by a load-to-failure test. Tendon elongation and load to rupture were measured. Results: No tendon failed or lengthened during cyclic testing. The mean load to failure for peroneus brevis was 416 N (95% confidence interval, 351–481 N) and for the peroneus longus was 723 N (95% confidence interval, 578–868 N). All failures were at the level of the defect created. Conclusion: In a cadaveric model of peroneal tendon tears, 33% of remaining peroneal tendon could resist high tensile forces, above the physiologic threshold. Clinical Relevance: Some peroneal tendon tears can be treated conservatively without risking spontaneous ruptures. When surgically treating a symptomatic peroneal tendon tear, increased efforts may be undertaken to repair tears previously considered irreparable.Item Proximal and Distal Failure Site Analysis in Percutaneous Achilles Tendon Rupture Repair(2019) Wagner, Pablo; Wagner, Emilio; López, M.; Etchevers, G.; Valencia, O.; Guzmán-Venegas, RodrigoBackground: Different techniques have been described for percutaneous Achilles tendon rupture repair, but no biomechanical evaluation has been performed separately for proximal and distal suturing techniques. The purpose of this study was to biomechanically analyze proximal versus distal percutaneous Achilles suture configurations during cyclic loading and load to failure. Methods: A simulated, midsubstance rupture was created 6 cm proximal to the calcaneal insertion in fresh-frozen cadaveric Achilles tendons. Fifteen proximal specimens were divided into 3 groups: (A1) triple locking technique, (A2) Bunnell-type technique, and (A3) double Bunnell-type technique. Twelve distal specimens were divided into 2 groups: (B1) triple nonlocking technique and (B2) oblique technique. Repairs were subjected to cyclic testing and load to failure. Load to failure, cause of failure, and tendon elongation were evaluated. Results: None of the proximal specimens and 7/12 of the distal ones failed in cyclic testing. The proximal fixation groups demonstrated significantly more strength than the distal groups (P = .001), achieving up to 710 N of failure load in Group A3. Groups B1and B2 failed on average at 380 N with no difference between them (P > .05). The majority of all repairs failed in the suture-tendon interface. Distal groups had more elongation during cyclic testing (13.7 mm) than proximal groups (9.4 mm) (P = .02). Conclusion: The distal fixation site in this Achilles tendon repair was significantly weaker than the proximal fixation site. A proximal modified suture configuration increased resistance to cyclic loading and load to failure significantly. Clinical Relevance: A modification can be suggested to improve strength of the Achilles repair.