{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:51:25Z","timestamp":1760233885771,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,3,2]],"date-time":"2021-03-02T00:00:00Z","timestamp":1614643200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: A major disadvantage of current spacers for two-stage revision total knee arthroplasty (R-TKA) is the risk of (sub-) luxation during mobilization in the prosthesis-free interval, limiting their clinical success with detrimental consequences for the patient. The present study introduces a novel inverse spacer, which prevents major complications, such as spacer (sub-) luxations and\/or fractures of spacer or bone. Methods: The hand-made inverse spacer consisted of convex tibial and concave femoral components of polymethylmethacrylate bone cement and was intra-operatively molded under maximum longitudinal tension in 5\u00b0 flexion and 5\u00b0 valgus position. Both components were equipped with a stem for rotational stability. This spacer was implanted during an R-TKA in 110 knees with diagnosed or suspected periprosthetic infection. Postoperative therapy included a straight leg brace and physiotherapist-guided, crutch-supported mobilization with full sole contact. X-rays were taken before and after prosthesis removal and re-implantation. Results: None of the patients experienced (sub-) luxations\/fractures of the spacer, periprosthetic fractures, or soft tissue compromise requiring reoperation. All patients were successfully re-implanted after a prosthesis-free interval of 8 weeks, except for three patients requiring an early exchange of the spacer due to persisting infection. In these cases, the prosthetic-free interval was prolonged for one week. Conclusion: The inverse spacer in conjunction with our routine procedure is a safe and cost-effective alternative to other articulating or static spacers, and allows crutch-supported sole contact mobilization without major post-operative complications. Maximum longitudinal intra-operative tension in 5\u00b0 flexion and 5\u00b0 valgus position appears crucial for the success of surgery.<\/jats:p>","DOI":"10.3390\/jcm10050971","type":"journal-article","created":{"date-parts":[[2021,3,2]],"date-time":"2021-03-02T01:49:44Z","timestamp":1614649784000},"page":"971","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["The Inverse Spacer\u2014A Novel, Safe, and Cost-Effective Approach in Routine Procedures for Revision Knee Arthroplasty"],"prefix":"10.3390","volume":"10","author":[{"given":"Kristoff","family":"Hammerich","sequence":"first","affiliation":[{"name":"Department of Orthopaedic Surgery, Eichsfeld Klinikum gGmbH, Academic Teaching Hospital of the University of Goettingen, 37308 Heilbad Heiligenstadt, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jens","family":"Pollack","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, SRH Wald-Klinikum Gera, Academic Teaching Hospital of the University of Jena, 07548 Gera, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alexander F.","family":"Hasse","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine 1, Section of Hematology\/Oncology\/Rheumatology, University Hospital Homburg, 66421 Homburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andr\u00e9","family":"El Saman","sequence":"additional","affiliation":[{"name":"Department of Trauma, Hand and Reconstructive Surgery, University Hospital Frankfurt, 60590 Frankfurt am Main, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1041-9935","authenticated-orcid":false,"given":"Ren\u00e9","family":"Huber","sequence":"additional","affiliation":[{"name":"Experimental Rheumatology Unit, Department of Orthopedics, Jena University Hospital, Waldkliniken Eisenberg GmbH, 07607 Eisenberg, Germany"},{"name":"Institute of Clinical Chemistry, Hannover Medical School, 30625 Hannover, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Markus","family":"Rupp","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Hospital Regensburg, 93053 Regensburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Volker","family":"Alt","sequence":"additional","affiliation":[{"name":"Department of Trauma Surgery, University Hospital Regensburg, 93053 Regensburg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6104-482X","authenticated-orcid":false,"given":"Raimund W.","family":"Kinne","sequence":"additional","affiliation":[{"name":"Experimental Rheumatology Unit, Department of Orthopedics, Jena University Hospital, Waldkliniken Eisenberg GmbH, 07607 Eisenberg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joerg","family":"Mika","sequence":"additional","affiliation":[{"name":"Experimental Rheumatology Unit, Department of Orthopedics, Jena University Hospital, Waldkliniken Eisenberg GmbH, 07607 Eisenberg, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Boelch, S.P., Jakuscheit, A., Doerries, S., Fraissler, L., Hoberg, M., Arnholdt, J., and Rudert, M. 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Arthroplast."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/10\/5\/971\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:31:09Z","timestamp":1760160669000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/10\/5\/971"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,2]]},"references-count":26,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["jcm10050971"],"URL":"https:\/\/doi.org\/10.3390\/jcm10050971","relation":{},"ISSN":["2077-0383"],"issn-type":[{"type":"electronic","value":"2077-0383"}],"subject":[],"published":{"date-parts":[[2021,3,2]]}}}