Browsing by Author "Radkievich, Rubén"
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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 Biomechanical Evaluation of Circumtibial and Transmembranous Routes for Posterior Tibial Tendon Transfer for Dropfoot(2018) Wagner, Emilio; Wagner, Pablo; Zanolli, Diego; Radkievich, Rubén; Redenz, Gunther; Guzmán, RodrigoBackground: Tibialis posterior tendon transfer is performed when loss of dorsiflexion has to be compensated. We evaluated the circumtibial (CT), above-retinaculum transmembranous (TMAR), and under-retinaculum transmembranous (TMUR) transfer gliding resistance and foot kinematics in a cadaveric foot model during ankle range of motion (ROM). Methods: Eight cadaveric foot-ankle distal tibia specimens were dissected free of soft tissues on the proximal end, applying an equivalent force to 50% of the stance phase to every tendon, except for the Achilles tendon. Dorsiflexion was tested with all of the tibialis posterior tendon transfer methods (CT, TMAR, and TMUR) using a tension tensile machine. A 10-repetition cycle of dorsiflexion and plantarflexion was performed for each transfer. Foot motion and the force needed to achieve dorsiflexion were recorded. Results: The CT transfer showed the highest gliding resistance (P < .01). Regarding kinematics, all transfers decreased ankle ROM, with the CT transfer being the condition with less dorsiflexion compared with the control group (6.8 vs 15 degrees, P < .05). TMUR transfer did perform better than TMAR with regard to ankle dorsiflexion, but no difference was shown in gliding resistance. The CT produced a supination moment on the forefoot. Conclusion: The CT transfer had the highest tendon gliding resistance, achieved less dorsiflexion and had a supination moment. Clinical Relevance We suggest that the transmembranous tibialis posterior tendon transfer should be the transfer of choice. The potential bowstringing effect when performing a tibialis posterior tendon transfer subcutaneously (TMAR) could be avoided if the transfer is routed under the retinaculum, without significant compromise of the final function and even with a possible better ankle range of motion.