Aseptic Loosening Rate of the Mayo Femoral Stem With Medium-Term Follow Up Luis G.G. Martins, MD , Flávio L. Garcia, PhD, MD, Celso H.F. Picado, PhD, MD University Hospital/Ribeirão Preto Medical School/DBMRAL, Avenida Bandeirantes, 3900, 11 Andar, Campus Universitário, Bairro Monte Alegre, Ribeirão Preto, São Paulo, Brazil abstract article info Article history: Received 8 November 2013 Accepted 24 June 2014 Keywords: hip arthroplasty conservative stem metaphyseal stem short stem mayo stem aseptic loosening The aseptic loosening rate of the Mayo hip prosthesis femoral stem was determined in a 44 patient (52 hips) series, by comparing preoperative and postoperative clinical and radiographic parameters, over a minimal 5-year postoperative period. Loosening was obvious before five years in four hips (7.6%), while the stem was considered stable in the remaining 48 hips over a mean 6.1 year period, therefore accounting for a 92.3% Kaplan–Meier survival rate. We conclude that the aseptic loosening rate is too high for the Mayo hip prosthesis femoral stem, as compared to literature data concerning the non-conservative stems. © 2014 Elsevier Inc. All rights reserved. In order to further improve the survival of hip arthroplasties several modifications were conceived altering design, fixation and bearing surface [1]. These modifications have extended hip arthro- plasty indications to young patients who demand more from the replaced joint and present greater aseptic loosening rates [2]. Conservative implants were designed with the purpose of preserving the proximal femoral bone stock [3]. One of the proposed modifications was the metaphyseal-fixation femoral stem with a shorter extension in the femoral canal such as the Mayo conservative hip (Zimmer, Warsaw, Indiana). Theoretically, this implant would have the advantage of preserving the distal femoral canal if revision surgery should become necessary. Preserving the distal bone envelope would be advantageous provided the stem remained well fixed in the metaphyseal area, with no evidence of aseptic loosening, for a longer period of time than the previously reported for the non-conservative implants [4,5]. The results reported by the designers of the Mayo were acceptable after implantation in a young and active population [6]. Morrey et al in 2000 [6] published 7.4% aseptic loosening rate, Falez et al in 2008 [4] published 1.1% aseptic loosening rate, Haegel et al in 2008 [7] published 1.8% aseptic loosening rate, Goelbel et al in 2009 [8] published 6.6% aseptic loosening rate, Gilbert et al in 2009 [9] published 10.2% aseptic loosening rate and the Australian National Replacement Registry Annual Report in 2011 [10] published 3% aseptic loosening rate. Our objective was to determine aseptic loosening rate of the Mayo Femoral stem and compare to traditionally stemmed implants through clinical and radiographic evaluation. Patients and Methods Patients Between June 2002 and December 2005, two surgeons from one institution performed a consecutive series of total hip arthroplasty procedures with the Mayo Hip Stem in 57 patients (65 hips). The inclusion criterion was patients with an indication for cementless primary hip arthroplasty. Thirteen patients (13 hips) were excluded due to lack of complete clinical and radiographic documentation. Forty one patients (48 hips) were evaluated with mean follow-up period of 6.1 years (5 to 7.5 years). Four patients (four hips) were added with aseptic loosening stem before five years (mean follow of 2.7 years; 2 to 3 years). One patient with bilateral arthroplasty presented a fixed stem in one side and loose in the other. Patient age ranged from 23 to 66 years (m = 48.54 years); body mass index (BMI) ranged from 17.63 to 39.21 (m = 26.90). There were 27 men and 17 women. Diagnoses were femoral head osteonecrosis (AVN) in 17 (38.6%), osteoarthritis (OA) in 16 (36.3%), non-union of a femoral neck fracture (FNF) in seven (15.9%) and other in four (8.8%). The other diagnoses were development dysplasia of the hip, renal osteodystrophy, epiphysiolysis and vilonodular synovits, none of them with aseptic loosening stem (Table 1). Implants The Trilogy acetabular system shell, Trilogy acetabular system liner and the Zimtron femoral head with Mayo hip corundumized stem (Zimmer, Warsaw, Indiana) were used for all procedures. The Journal of Arthroplasty 29 (2014) 2122–2126 The Conflict of Interest statement associated with this article can be found at http://dx. doi.org/10.1016/j.arth.2014.06.023. Reprint requests: Luis Gustavo Gazoni Martins, MD, University Hospital/Ribeirão Preto Medical School, DBMRAL, Avenida Bandeirantes, 3900, 11 Andar, Campus Universitário, 14048-900 Ribeirao Preto, Brazil. http://dx.doi.org/10.1016/j.arth.2014.06.023 0883-5403/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org