{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,17]],"date-time":"2026-05-17T04:17:24Z","timestamp":1778991444793,"version":"3.51.4"},"reference-count":44,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,12,22]],"date-time":"2020-12-22T00:00:00Z","timestamp":1608595200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001702","name":"AO Foundation","doi-asserted-by":"publisher","award":["AO Trauma AR2016_06"],"award-info":[{"award-number":["AO Trauma AR2016_06"]}],"id":[{"id":"10.13039\/501100001702","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This manuscript introduces a programable active bone fixator system that enables systematic investigation of bone healing processes in a sheep animal model. In contrast to previous systems, this solution combines the ability to precisely control the mechanical conditions acting within a fracture with continuous monitoring of the healing progression and autonomous operation of the system throughout the experiment. The active fixator system was implemented on a double osteotomy model that shields the experimental fracture from the influence of the animal\u2019s functional loading. A force sensor was integrated into the fixator to continuously measure stiffness of the repair tissue as an indicator for healing progression. A dedicated control unit was developed that allows programing of different loading protocols which are later executed autonomously by the active fixator. To verify the feasibility of the system, it was implanted in two sheep with different loading protocols, mimicking immediate and delayed weight-bearing, respectively. The implanted devices operated according to the programmed protocols and delivered seamless data over the whole course of the experiment. The in vivo trial confirmed the feasibility of the system. Hence, it can be applied in further preclinical studies to better understand the influence of mechanical conditions on fracture healing.<\/jats:p>","DOI":"10.3390\/s21010017","type":"journal-article","created":{"date-parts":[[2020,12,22]],"date-time":"2020-12-22T20:39:29Z","timestamp":1608669569000},"page":"17","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Programable Active Fixator System for Systematic In Vivo Investigation of Bone Healing Processes"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3730-5134","authenticated-orcid":false,"given":"Jan","family":"Barcik","sequence":"first","affiliation":[{"name":"AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland"},{"name":"Bulgarian Academy of Sciences, Institute of Metal Science \u2018Acad. A. Balevski\u2019, Shipchenski prohod 67, 1574 Sofia, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manuela","family":"Ernst","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Constantin E.","family":"Dlaska","sequence":"additional","affiliation":[{"name":"Orthopaedic Research Institute of Queensland, 7 Turner Street, Townsville, QLD 4812, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ludmil","family":"Drenchev","sequence":"additional","affiliation":[{"name":"Bulgarian Academy of Sciences, Institute of Metal Science \u2018Acad. A. Balevski\u2019, Shipchenski prohod 67, 1574 Sofia, Bulgaria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8155-4202","authenticated-orcid":false,"given":"Stephan","family":"Zeiter","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Devakara R.","family":"Epari","sequence":"additional","affiliation":[{"name":"Institute of Health and Biomedical Innovation, Queensland University of Technology, George Street 2, Brisbane City, QLD 4000, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8077-6914","authenticated-orcid":false,"given":"Markus","family":"Windolf","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1016\/j.injury.2011.03.046","article-title":"Treatment of long bone non-unions with polytherapy: Indications and clinical results","volume":"42","author":"Calori","year":"2011","journal-title":"Injury"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"111","DOI":"10.4103\/0019-5413.50843","article-title":"Global burden of trauma: Need for effective fracture therapies","volume":"43","author":"Mathew","year":"2009","journal-title":"Indian J. 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