PURPOSE OF THE STUDY: In the development of cementless total hip arthroplasty wear, loosening as well as stress shielding are considered as major issues. New results in literature specify survivorship of THA over 97%. Consequently the implant loosening and wear especially can be considered as almost solved. Therefore, it is essential to use bone preserving primary implants that allow for a physiological load transfer and cause no or only slight stress shielding at the proximal femur. The MAYO conservative hip stem with a wedge design ensuring immediate primary fixation of the stem with metaphyseal load transfer. MATERIAL AND METHODS: A retrospective study was performed to review the first consecutive 316 MAYO conservative hip stems implanted at the Martin-Luther-University of Halle-Wittenberg (Germany). 85.4% (270 MAYO stems) were radiographic analysed and classified according to the HHS. RESULTS: The mean HHS improved from 44.79 preoperatively to 93.58 postoperatively. 1.85% (5 MAYO stems) had to be replaced because of aseptic loosening. Furthermore the DEXA scans revealed the metaphyseal load transfer with increased bone density in the calcar region. CONCLUSION: As especially younger patients will require one or more hip revision procedures during the course of their life due to their life due to their age and activity level. These patients should receive a primary implant with proximal load transfer. Only these implants can avoid stress shielding of the proximal femur. The minimally invasive implantation of these implants can also ensure an enhanced periprosthetic bone density an optimized postoperative rehabilitation phase.
PURPOSE OF THE STUDY: In the development of cementless total hip arthroplasty wear, loosening as well as stress shielding are considered as major issues. New results in literature specify survivorship of THA over 97%. Consequently the implant loosening and wear especially can be considered as almost solved. Therefore, it is essential to use bone preserving primary implants that allow for a physiological load transfer and cause no or only slight stress shielding at the proximal femur. The MAYO conservative hip stem with a wedge design ensuring immediate primary fixation of the stem with metaphyseal load transfer. MATERIAL AND METHODS: A retrospective study was performed to review the first consecutive 316 MAYO conservative hip stems implanted at the Martin-Luther-University of Halle-Wittenberg (Germany). 85.4% (270 MAYO stems) were radiographic analysed and classified according to the HHS. RESULTS: The mean HHS improved from 44.79 preoperatively to 93.58 postoperatively. 1.85% (5 MAYO stems) had to be replaced because of aseptic loosening. Furthermore the DEXA scans revealed the metaphyseal load transfer with increased bone density in the calcar region. CONCLUSION: As especially younger patients will require one or more hip revision procedures during the course of their life due to their life due to their age and activity level. These patients should receive a primary implant with proximal load transfer. Only these implants can avoid stress shielding of the proximal femur. The minimally invasive implantation of these implants can also ensure an enhanced periprosthetic bone density an optimized postoperative rehabilitation phase.
Authors: Jakob van Oldenrijk; Jeroen Molleman; Michel Klaver; Rudolf W Poolman; Daniel Haverkamp Journal: Acta Orthop Date: 2014-04-03 Impact factor: 3.717