Klestil, ThomasThomasKlestilMorlock, MichaelMichaelMorlockSchwieger, KarstenKarstenSchwiegerSellenschloh, KayKaySellenschlohCurda, B.B.CurdaBiedermann, R.R.BiedermannHennerbichler, A.A.HennerbichlerSchmoelz, W.W.SchmoelzRabl, W.W.RablBlauth, M.M.Blauth2024-03-192024-03-192006-08-01Archives of Orthopaedic and Trauma Surgery 126 (6): 387-393 (2006)https://hdl.handle.net/11420/46633The aim of the present in vitro study was to evaluate migrational characteristics of cementless primary hip arthroplasty stems in combination with a Ø 50 mm head (hemiarthroplasty) and a Ø 28 mm head in and with a polyethylene cup (total hip arthroplasty) in fresh-frozen human specimens. Two different types (Endo SL®, FMT®) were implanted into seven pairs of fresh-frozen human femoral specimens. The implanted stems were combined with a Ø 50 mm head (hemiarthroplasty) on one side and with a polyethylene cup and a 28 mm head (total hip arthroplasty) on the other side. Dynamic mechanical loading was applied for 50,000 cycles while recording relative motions between stem and bone stock using a 3-D motion analysis system. The Endo SL® stem showed a significantly higher amplitude of relative motion in all translational and rotational components regardless of the head used. In both stem types a strong tendency for higher axial migration with the Ø 50 mm head in comparison to the THA head was found. The lowest axial migration was found in the FMT® stem in combination with the small head and a PE cup. The highest axial migration was found in the Endo SL® stem combined with the Ø 50 mm head. Our results indicate that the head might play an important role for axial migration of cementless stems. © Springer-Verlag 2006.en0936-805120066387393SpringerBiomechanicsHemiarthroplastyMigrationTotal hip arthroplastyMedicine, HealthEngineeringJournal Article10.1007/s00402-006-0136-3Journal Article