Surfaces In Total Hip Replacement Research Articles

Alumina ceramic-on-ceramic hybrid total hip arthroplasty. A median of 15 years follow-up

The optimum choice of bearing surfaces in total hip replacement (THR) in the younger and active patient remains controversial. The aim of this study was to report the 10year clinical outcomes, and a median of 15year implant survival and incidence of complications in a series of Alumina ceramic-on-ceramic THRs utilising an uncemented shell and cemented stem. From January 2004 to December 2007, 175 consecutive patients (195 hips) underwent primary THR. The acetabular components was Trident Peripheral Self Locking (Stryker Orthopaedics) with a third-generation ceramic head and liner (Alumina ceramic, Stryker Orthopaedics). The stem utilised was an Exeter V-40 (Stryker Orthopaedics). Data were collated on demographics, surgical factors, clinical outcomes, radiographic outcomes and revision. 23 patients (27 THRs) died during the follow-up period at a median of 7.8 (3.8 to 9.0) years post-operatively due to causes unrelated to the THR. Median age at time of surgery was 55 (interquartile range 48-60) years. Median follow-up for surviving patients was 15.2years. Survivorship for all-cause revision was 97.2%. Increasing patient age at time of surgery was associated with a higher OHS at 10years (p = 0.022). 32mm head diameter had an improved OHS at 3months (p = 0.014) and 10years (p = 0.030). Posterior surgical approach had a statistically significant better OHS at 3months (p = 0.015) and 1year (p < 0.001), but the effect was not significant at 10years (p = 0.440). The findings of this study support excellent long-term outcomes and survivorship of Alumina ceramic-on-ceramic bearing in a hybrid THR in a younger population. Surgical factors leading to a more favourable outcome were the use of a 32mm femoral head and a posterior approach. Increasing age at surgery demonstrated the most sustained improvement in 10year clinical outcomes.

Wear of large diameter ceramic-on-ceramic hip bearings under standard and microseparation conditions

A novel Ceramic-on-Ceramic hip resurfacing implant offers a bone conserving treatment for young and/or active patients without the metal ion related issues associated with current Metal-on-Metal (MoM) hip resurfacing devices. BIOLOX delta ceramics are currently used as bearing surfaces in total hip replacement and have shown to be low wearing and biocompatible. Wear testing, however, has only been conducted in bearing diameters up to 36 mm and it is unknown how this material will perform tribologically and clinically in larger bearing diameters. The smallest (40 mm diameter) and largest (64 mm diameter) bearings of aceramic resurfacing implant size range were tested to ISO 14242-1 and ISO 14242-2 standards The largest size was also tested under microseparation wear conditions in a physiological hip simulator for 5 million cycles. The wear rate over the full 5mc was shown to not be influenced by the size of implant but at specific time points, there was a statistical significance, and in all cases steady state wear was low (≤0.5mm3/mc). The introduction of microseparation conditions increased the wear rate compared to standard conditions and produced stripe wear on the heads. The low wear and biocompatible nature of the BIOLOX delta material suggests it is a suitable material for use in hip resurfacing which may open this treatment option for patients who are currently not appropriate for MoM hip resurfacing.

The choice between hip prosthetic bearing surfaces in total hip replacement: a protocol for a systematic review and network meta-analysis.

BackgroundProsthetic hip implants have many combinations of bearing surface materials, sizes, and fixation techniques, which can determine the quality of life of patients after primary total hip replacement (THR) and the likelihood of needing revision surgery. When an implant fails, patients require revision THR, which is distressing to the patient and expensive for the health care payer. Primary THR is one of the most common elective procedures performed worldwide, with over 300,000 performed annually in the USA and over 80,000 in England and Wales. It is important to review all available randomised controlled trial (RCT) evidence to determine which implant bearing surface materials, size, and fixation technique are most effective for patients.Methods/DesignThis is a protocol for a systematic review and meta-analysis of RCTs comparing outcomes of hip implant bearing surfaces, size, and fixation techniques used in THR. Implant combinations compared in the literature include four bearing surface combinations (metal-on-polyethylene, metal-on-metal, ceramic-on-polyethylene, and ceramic-on-ceramic); two femoral head sizes (large vs small heads); and four fixation techniques (uncemented, cemented, hybrid, and reverse hybrids). The primary outcome will be revision surgery. We will also collect data on patient characteristics, mortality, quality of life, and other outcomes. In network meta-analysis, we will estimate the relative effectiveness of every implant bearing surface, head size (large vs small), and fixation permutation, using evidence where implants have been compared directly in an RCT and indirectly through common comparators in different RCTs.DiscussionThere has been much debate about materials used for prosthetic implants in THR. Different combinations of prosthetic materials, sizes, and fixation, can vary widely in cost and fail at different rates for different patient groups. Given the number of THRs performed yearly, and the increasing use of expensive implants, it is important to review evidence to inform surgeons, patients, and health care providers of optimal implant bearing combinations for given patient characteristics. This review will inform a cost-effectiveness model that will include evidence from other sources, to determine the most effective and cost-effective implant bearing combination for patients.Systematic review registrationPROSPERO CRD42015019435

Ceramic-on-ceramic total hip arthroplasty: A new standard—Affirms

Highly cross-linked polyethylene has emerged as an improvement over conventional polyethylene in terms of wear characteristics and osteolysis in total hip replacement; however, decreased material properties could make it unsuitable for use in high-demand patients. Modern ceramic-on-ceramic bearings display extremely low wear and durability that make them an ideal bearing surface. Unfortunately, certain implant designs have been associated with squeaking, which has discouraged widespread use. Proper implant selection, orientation, and surgical technique can lead to optimal results with ceramic bearings, and substantial mid- to long-term data exists to support their use over other bearing surfaces in total hip replacement.

The current state of bearing surfaces in total hip replacement

We reviewed the literature on the currently available choices of bearing surface in total hip replacement (THR). We present a detailed description of the properties of articulating surfaces review the understanding of the advantages and disadvantages of existing bearing couples. Recent technological developments in the field of polyethylene and ceramics have altered the risk of fracture and the rate of wear, although the use of metal-on-metal bearings has largely fallen out of favour, owing to concerns about reactions to metal debris. As expected, all bearing surface combinations have advantages and disadvantages. A patient-based approach is recommended, balancing the risks of different options against an individual's functional demands.

A prospective, randomised controlled trial comparing ceramic-on-metal and metal-on-metal bearing surfaces in total hip replacement

In a double-blinded randomised controlled trial, 83 patients with primary osteoarthritis of the hip received either a ceramic-on-metal (CoM) or metal-on-metal (MoM) total hip replacement (THR). The implants differed only in the bearing surfaces used. The serum levels of cobalt and chromium and functional outcome scores were compared pre-operatively and at six and 12 months post-operatively. Data were available for 41 CoM and 36 MoM THRs (four patients were lost to follow-up, two received incorrect implants). The baseline characteristics of both cohorts were similar. Femoral head size measured 36 mm in all but two patients who had 28 mm heads. The mean serum cobalt and chromium levels increased in both groups, with no difference noted between groups at six months (cobalt p = 0.67, chromium p = 0.87) and 12 months (cobalt p= 0.76, chromium p = 0.76) post-operatively. Similarly, the mean Oxford hip scores, Western Ontario and McMaster Universities Osteoarthritis index and University of California, Los Angeles activity scores showed comparable improvement at 12 months. Our findings indicate that CoM and MoM couplings are associated with an equivalent increase in serum cobalt and chromium levels, and comparable functional outcome scores at six and 12-months follow-up.

A short-term comparison of metal-on-metal and metal-on-polyethylene bearing surfaces in total hip replacement

Objective To compare the short-term results of metal-on-metal (MOM) and metal-on-polyethylene (MOP) bearing surfaces in total hip replacement (THR). Methods Thirty cases, 12 males and 18 females, received MOM THR through a posterolateral surgical approach from June 2007 to December 2008. Their mean age was 60.3 years, mean body mass index (BMI) was 23.7 g/m2 and mean Harris score was 36 ± 15 preoperatively. For comparison, another 30 cases, 9 males and 21 females, received MOP THR through the same approach at the same period. Their mean age was 62.4 years, mean BMI was 23.4 kg/m2 and mean Harris score was 34 ± 17 preoperatively. The 2 groups were compared in terms of hip functional recovery and radiographic examination. Results All patients obtained an average follow-up of 14.4 months (range, 12 to 18 months) . No infection, fracture or neurovascular injury occurred in either group. There were one deep venous thrombosis and one dislocation in the MOP group. The average Harris scores at 1, 3, 6, 12 months postoperatively were respectively 78 ±4, 84 ±4, 90 ±3, 92 ±4 for the MOP group and 86 ± 3, 90 ± 3, 95 ± 4, 95 ± 3 for the MOM group. The differences between the 2 groups were significant at 1, 3, 6 months ( P ＜ 0.05) but insignificant at 12 months ( P ＞ 0.05). In the MOM group,the total range of hip motion averaged 239.2°± 21.9° and the hip inflexion averaged 135.4°± 10.9°. In the MOP group, the total range of hip motion averaged 190.1°± 16.7° and the hip inflexion averaged 95.3°± 11.3°. The differences between the 2 groups were significant ( P ＜ 0.05). Conclusion On a short-term basis, MOM THR may be better than MOP THR, but the medium and long-term results of MOM bearing surfaces still need further investigation. Key words: Arthroplasty, replacement, hip; Prostheses and implants; Treatment outcome

Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations

We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component. Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 microg/L and 1.62 microg/L respectively (p = 0.819) and for Co, 0.67 microg/L and 0.94 microg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 microg/L in hip resurfacing and and 1.30 microg/L in total hip replacement (p = 0.001). The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement.

Large Diameter Femoral Heads on Highly Cross-linked Polyethylene

Contemporary highly cross-linked polyethylenes have become the most widely used alternative bearing surfaces in total hip replacement and may be paired with large diameter femoral heads (> 32 mm) in patients considered to be at high risk for dislocation. We report on a prospective series of 42 patients (45 hips) who had total hip replacement using large diameter cobalt-chrome femoral heads articulating with a highly cross linked polyethylene after a minimum of 3 years followup (mean 3.3 years). At final followup, the final patient cohort showed excellent clinical results with no radiographic failures or episodes of loosening. There was no evidence of pelvic or femoral osteolysis. One patient sustained a dislocation due to a grossly malpositioned acetabular component necessitating early isolated acetabular revision. The average yearly steady state wear rate was -0.06 +/- 0.41 mm/year. The results of our short-term prospective series indicated total hip replacement with large femoral heads articulating with a highly cross linked polyethylene showed excellent wear characteristics and clinical results and could be considered in patients at increased risk for dislocation.

Ceramic femoral head retrieval data.

In the 1970s it was first realized that the properties of alumina ceramics could be exploited to provide better implants for orthopaedic applications. Applications depend on the fact that ceramics provided wear characteristics suitable for bearing surfaces in total hip replacement. Resultant orthopaedic use had more than 20 years' clinical success. To date more than 2.5 million alumina femoral heads have been implanted. Published reports of fracture rates of the alumina heads range between 0% for ceramics manufactured after 1990 and 13.4% for ceramics manufactured before 1990. These high fracture rates were caused by materials manufactured by companies that are not on the market today. These old aluminas had a low density, had a very coarse microstructure, and were not in compliance with specifications that are valid today. Materials scientists have substantially improved the mechanical strength of alumina. There are three generations of medical grade aluminas. The latest generation is an alumina that is hot isostatic pressed, laser marked, and proof tested. This material has been on the market since 1994. The fracture rates of the most commonly used ceramics have been analyzed by various groups, and are based on .5 million femoral heads to 1.5 million femoral heads. The fracture rate of ceramic Biolox femoral heads are 0.026 % for first generation alumina, 0.014% for second generation alumina, and 0.004% for femoral heads manufactured after 1994. Analyzing the clinical experience of more than 20 years, it can be concluded that all the improvements have produced reliable ceramic femoral heads.