Clinical outcomes of cemented double-tapered titanium femoral stems: A minimum 5-year follow-up
Department of Orthopaedics, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto, 606-8507, Japan. Journal of Orthopaedic Science
(Impact Factor: 0.94).
09/2011; 16(6):689-97. DOI: 10.1007/s00776-011-0154-z
The clinical outcomes and radiological findings for cemented titanium stems remain controversial. In 2004, we produced a straight-collared double-tapered stem made from a titanium alloy with a smooth surface for cemented total hip arthroplasty. In this study, we retrospectively examined the mid-term outcomes of this stem.
We retrospectively reviewed 61 hips that had undergone primary cemented total hip arthroplasty with a collared smooth double-tapered titanium alloy femoral stem, after a minimum of 5 years (mean 6.1, range 5.0-7.3). Patients were evaluated preoperatively and postoperatively with the Merle d'Aubigné and Postel hip score. Radiographic examination was performed for evaluation of the cementing technique, the alignment of the stem, subsidence within the cement mantle, radiolucent lines at the cement-bone or cement-stem interface, cortical hypertrophy, and calcar resorption.
The clinical evaluation by the Merle d'Aubigné and Postel hip score was improved from 9.4 ± 1.9 preoperatively to 15.9 ± 1.6 at the time of final follow-up. The overall survival rate was 100% at 7 years, when radiological loosening or revision for any reasons was used as the endpoint. Five stems subsided less than 1 mm vertically. Nonprogressive radiolucence at the cement-bone interface occurred in six hips, without osteolysis. Cortical hypertrophy was observed in five hips and second-degree calcar resorption in 11 hips.
Our results in this study show good outcomes for cemented, collared, smooth, double-tapered titanium alloy femoral stems at a minimum follow-up of 5 years.
Available from: Cory Xian
- "For examples, Müller straight titanium stems, after 15 years, had a survival rate of 75.4%, while after 8 years, the survival rate of titanium stems with rough surface was 76.7% (Akiyama et al., 2010, 2011; Francetti et al., 2014). Consequently, due to these conflicting reports for many designs of titanium stems applied to the clinic, these stems are no longer favored in the Western World populations and to a great extent cemented femoral stems made from CoCrMo or stainless steel have replaced titanium stems (Akiyama et al., 2011). Nevertheless, Haruhiko discovered that the body's physical load could have a great effect on loosening failures, and that the titanium alloy stems are significantly more suitable for Japanese as average Japanese body weight is 20 Kg lower than Eurpeans. "
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ABSTRACT: Although cemented titanium alloy is not favored currently in the Western world for its poor clinical and radiography outcomes, its lower modulus of elasticity and good biocompatibility are instrumental for its ability supporting and transforming physical load, and it is more suitable for usage in Chinese and Japanese populations due to their lower body weights and unique femoral characteristics. Through various friction tests of different cycles, loads and conditions and by examining fretting hysteresis loops, fatigue process curves and wear surfaces, the current study investigated fretting wear characteristics and wear mechanism of titanium alloy stem-bone cement interface. It was found that the combination of loads and displacement affected the wear quantity. Friction coefficient, which was in an inverse relationship to load under the same amplitude, was proportional to amplitudes under the same load. Additionally, calf serum was found to both lubricate and erode the wear interface. Moreover, cement fatigue contact areas appeared black/oxidative in dry and gruel in 25% calf serum. Fatigue scratches were detected within contact areas, and wear scars were found on cement and titanium surfaces, which were concave-shaped and ring concave/ convex-shaped, respectively. The coupling of thermoplastic effect and minimal torque damage has been proposed to be the major reason of contact damage. These data will be important for further studies analyzing metal-cement interface failure performance and solving interface friction and wear debris production issues.
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In cemented total hip arthroplasty (THA), a polished tapered femoral stem with a design based on the taper-slip concept enables extremely reliable and durable fixation. In contrast, cemented femoral stems made from titanium alloys are not favored because of reports describing insufficient clinical outcomes. However, we have reported excellent clinical and radiological outcomes for cemented titanium stems made using the composite-beam concept. This study examines the characteristics of cemented titanium femoral stems with a smooth surface.
The bonding strength between titanium alloys with different surface finishes and bone cement was evaluated by use of push-out and detachment tests. Torsional stability tests were performed to evaluate the initiation and propagation of disruption of the fixation of cemented stems at the cement–implant interface. The wear resistance was investigated by use of wear–friction tests performed using a multidirectional pin-on-disc machine. The bone strain loaded on to the femoral cortex was measured by use of an implanted Sawbone and analyzed by use of the finite element method.
The push-out and detachment tests revealed increasing cement adhesion strength with increasing degree of roughness of the metal surface. The torsional stability tests indicated that a load >1,000 N led to progressive debonding between the cement and the implant with a smooth surface finish. Interestingly, wear–friction tests revealed the wear rate for polished titanium surfaces was clearly higher than for smooth surfaces. In addition, the greater elasticity of titanium stems compared with cobalt–chromium stems transmitted the external load to the proximal side of the femur more effectively.
The smooth surface finish of the stems is an important factor for the satisfactory clinical and radiological outcomes of cemented titanium femoral stems. The greater elasticity of a titanium stem effectively transmits the external load to the medial side of the femur.
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ABSTRACT: Cementless fixation has been a principal method for fixation of orthopedic implants for decades. Accordingly, different rough and porous surfaces have been developed and applied in clinical use. A variety of these coatings are continuously investigated in order to improve bone-implant integration and enhance osteogenesis at the implant surface. One of the most important elements used in joint arthroplasty is titanium.
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