{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T12:28:54Z","timestamp":1766492934107,"version":"build-2065373602"},"reference-count":40,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2022,11,13]],"date-time":"2022-11-13T00:00:00Z","timestamp":1668297600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"AO Foundation"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: Intramedullary nailing of trochanteric fractures can be challenging and sometimes the clinical situation does not allow perfect implant positioning. The aim of this study was (1) to compare in human cadaveric femoral heads the biomechanical competence of two recently launched cephalic implants inserted in either an ideal (centre\u2013centre) or less-ideal anterior off-centre position, and (2) to investigate the effect of bone cement augmentation on their fixation strength in the less-ideal position. Materials and Methods: Fourty-two paired human cadaveric femoral heads were assigned for pairwise implantation using either a TFNA helical blade or a TFNA screw as head element, implanted in either centre\u2013centre or 7 mm anterior off-centre position. Next, seven paired specimens implanted in the off-centre position were augmented with bone cement. As a result, six study groups were created as follows: group 1 with a centre\u2013centre positioned helical blade, paired with group 2 featuring a centre\u2013centre screw, group 3 with an off-centre positioned helical blade, paired with group 4 featuring an off-centre screw, and group 5 with an off-centre positioned augmented helical blade, paired with group 6 featuring an off-centre augmented screw. All specimens were tested until failure under progressively increasing cyclic loading. Results: Stiffness was not significantly different among the study groups (p = 0.388). Varus deformation was significantly higher in group 4 versus group 6 (p = 0.026). Femoral head rotation was significantly higher in group 4 versus group 3 (p = 0.034), significantly lower in group 2 versus group 4 (p = 0.005), and significantly higher in group 4 versus group 6 (p = 0.007). Cycles to clinically relevant failure were 14,919 \u00b1 4763 in group 1, 10,824 \u00b1 5396 in group 2, 10,900 \u00b1 3285 in group 3, 1382 \u00b1 2701 in group 4, 25,811 \u00b1 19,107 in group 5 and 17,817 \u00b1 11,924 in group 6. Significantly higher number of cycles to failure were indicated for group 1 versus group 2 (p = 0.021), group 3 versus group 4 (p = 0.007), and in group 6 versus group 4 (p = 0.010). Conclusions: From a biomechanical perspective, proper centre\u2013centre implant positioning in the femoral head is of utmost importance. In cases when this is not achievable in a clinical setting, a helical blade is more forgiving in the less ideal (anterior) malposition when compared to a screw, the latter revealing unacceptable low resistance to femoral head rotation and early failure. Cement augmentation of both off-centre implanted helical blade and screw head elements increases their resistance against failure; however, this effect might be redundant for helical blades and is highly unpredictable for screws.<\/jats:p>","DOI":"10.3390\/medicina58111636","type":"journal-article","created":{"date-parts":[[2022,11,14]],"date-time":"2022-11-14T02:32:01Z","timestamp":1668393121000},"page":"1636","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Impact of Anterior Malposition and Bone Cement Augmentation on the Fixation Strength of Cephalic Intramedullary Nail Head Elements"],"prefix":"10.3390","volume":"58","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4357-236X","authenticated-orcid":false,"given":"Torsten","family":"Pastor","sequence":"first","affiliation":[{"name":"AO Research Institute Davos, 7270 Davos, Switzerland"},{"name":"Department of Orthopaedic and Trauma Surgery, Lucerne Cantonal Hospital, 6000 Lucerne, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0484-887X","authenticated-orcid":false,"given":"Ivan","family":"Zderic","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, 7270 Davos, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Clemens","family":"Schopper","sequence":"additional","affiliation":[{"name":"Department for Orthopaedics and Traumatology, Kepler University Hospital GmbH, Johannes Kepler University Linz, 4020 Linz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pascal C.","family":"Haefeli","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic and Trauma Surgery, Lucerne Cantonal Hospital, 6000 Lucerne, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1454-7640","authenticated-orcid":false,"given":"Philipp","family":"Kastner","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, 7270 Davos, Switzerland"},{"name":"Department for Orthopaedics and Traumatology, Kepler University Hospital GmbH, Johannes Kepler University Linz, 4020 Linz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1087-7503","authenticated-orcid":false,"given":"Firas","family":"Souleiman","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, 7270 Davos, Switzerland"},{"name":"Department of Orthopaedics, Trauma and Plastic Surgery, University Hospital Leipzig, 04103 Leipzig, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9795-115X","authenticated-orcid":false,"given":"Boyko","family":"Gueorguiev","sequence":"additional","affiliation":[{"name":"AO Research Institute Davos, 7270 Davos, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9166-0965","authenticated-orcid":false,"given":"Matthias","family":"Knobe","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic and Trauma Surgery, Lucerne Cantonal Hospital, 6000 Lucerne, Switzerland"},{"name":"Medical Faculty, University of Zurich, 8091 Zurich, Switzerland"},{"name":"Medical Faculty, RWTH Aachen University Hospital, 52074 Aachen, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"314","DOI":"10.1007\/s00132-014-2265-7","article-title":"[Hip fractures in the elderly: Osteosynthesis versus joint replacement]","volume":"43","author":"Knobe","year":"2014","journal-title":"Orthopade"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Parker, M.J., and Handoll, H.H. 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