{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T16:56:01Z","timestamp":1790182561765,"version":"4.1.0"},"reference-count":44,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2022,7,27]],"date-time":"2022-07-27T00:00:00Z","timestamp":1658880000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000001","name":"National Science Foundation (US)","doi-asserted-by":"publisher","award":["1944001"],"award-info":[{"award-number":["1944001"]}],"id":[{"id":"10.13039\/100000001","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Prosthetic limbs that are completely implanted within skin (i.e., endoprostheses) could permit direct, physical muscle\u2013prosthesis attachment to restore more natural sensorimotor function to people with amputation. The objective of our study was to test, in a rabbit model, the feasibility of replacing the lost foot after hindlimb transtibial amputation by implanting a novel rigid foot\u2013ankle endoprosthesis that is fully covered with skin. We first conducted a pilot, non-survival surgery in two rabbits to determine the maximum size of the skin flap that could be made from the biological foot\u2013ankle. The skin flap size was used to determine the dimensions of the endoprosthesis foot segment. Rigid foot\u2013ankle endoprosthesis prototypes were successfully implanted in three rabbits. The skin incisions healed over a period of approximately 1 month after surgery, with extensive fur regrowth by the pre-defined study endpoint of approximately 2 months post surgery. Upon gross inspection, the skin surrounding the endoprosthesis appeared normal, but a substantial subdermal fibrous capsule had formed around the endoprosthesis. Histology indicated that the structure and thickness of the skin layers (epidermis and dermis) were similar between the operated and non-operated limbs. A layer of subdermal connective tissue representing the fibrous capsule surrounded the endoprosthesis. In the operated limb of one rabbit, the subdermal connective tissue layer was approximately twice as thick as the skin on the medial (skin = 0.43 mm, subdermal = 0.84 mm), ventral (skin = 0.80 mm, subdermal = 1.47 mm), and lateral (skin = 0.76 mm, subdermal = 1.42 mm) aspects of the endoprosthesis. Our results successfully demonstrated the feasibility of implanting a fully skin-covered rigid foot\u2013ankle endoprosthesis to replace the lost tibia\u2013foot segment of the lower limb. Concerns include the fibrotic capsule which could limit the range of motion of jointed endoprostheses. Future studies include testing of endoprosthetics, as well as materials and pharmacologic agents that may suppress fibrous encapsulation.<\/jats:p>","DOI":"10.3390\/bioengineering9080348","type":"journal-article","created":{"date-parts":[[2022,7,27]],"date-time":"2022-07-27T21:11:05Z","timestamp":1658956265000},"page":"348","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Feasibility of Implanting a Foot\u2013Ankle Endoprosthesis within Skin in a Rabbit Model of Transtibial Amputation"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9498-4308","authenticated-orcid":false,"given":"Dustin L.","family":"Crouch","sequence":"first","affiliation":[{"name":"Department of Mechanical, Aerospace & Biomedical Engineering, College of Engineering, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrick T.","family":"Hall","sequence":"additional","affiliation":[{"name":"Department of Mechanical, Aerospace & Biomedical Engineering, College of Engineering, University of Tennessee, Knoxville, TN 37996, USA"},{"name":"Exponent, Philadelphia, PA 19104, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Caleb","family":"Stubbs","sequence":"additional","affiliation":[{"name":"Department of Mechanical, Aerospace & Biomedical Engineering, College of Engineering, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7964-9229","authenticated-orcid":false,"given":"Caroline","family":"Billings","sequence":"additional","affiliation":[{"name":"Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alisha P.","family":"Pedersen","sequence":"additional","affiliation":[{"name":"Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bryce","family":"Burton","sequence":"additional","affiliation":[{"name":"Office of Laboratory Animal Care, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cheryl B.","family":"Greenacre","sequence":"additional","affiliation":[{"name":"Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stacy M.","family":"Stephenson","sequence":"additional","affiliation":[{"name":"Graduate School of Medicine, University of Tennessee, Knoxville, TN 37920, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0745-7591","authenticated-orcid":false,"given":"David E.","family":"Anderson","sequence":"additional","affiliation":[{"name":"Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,27]]},"reference":[{"key":"ref_1","first-page":"326","article-title":"The Southampton Hand: An intelligent myoelectric prosthesis","volume":"31","author":"Kyberd","year":"1994","journal-title":"J. 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