Failure rates of stemmed metal-on-metal hip replacements: analysis of data from the National Joint Registry of England and Wales

BACKGROUND

Total hip replacement (THR) is extremely common. Some prostheses fail, particularly in younger patients, and need to be revised, most commonly for loosening secondary to wear or dislocation. Surgeons have tried to address these problems by implanting large diameter metal-on-metal bearing surfaces. Our aim was to assess if metal-on-metal bearing surfaces lead to increased implant survival compared with other bearing surfaces in stemmed THR and, additionally, if larger head sizes result in improved implant survival.

METHODS

We analysed the National Joint Registry of England and Wales for primary hip replacements (402,051, of which 31,171 were stemmed metal-on-metal) undertaken between 2003 and 2011. Our analysis was with a multivariable flexible parametric survival model to estimate the covariate-adjusted cumulative incidence of revision adjusting for the competing risk of death.

FINDINGS

Metal-on-metal THR failed at high rates. Failure was related to head size, with larger heads failing earlier (3·2% cumulative incidence of revision [95% CI 2·5-4·1] for 28 mm and 5·1% [4·2-6·2] for 52 mm head at 5 years in men aged 60 years). 5 year revision rates in younger women were 6·1% (5·2-7·2) for 46 mm metal-on-metal compared with 1·6% (1·3-2·1) for 28 mm metal-on-polyethylene. By contrast, for ceramic-on-ceramic articulations larger head sizes were associated with improved survival (5 year revision rate of 3·3% [2·6-4·1] with 28 mm and 2·0% [1·5-2·7] with 40 mm for men aged 60 years).

INTERPRETATION

Metal-on-metal stemmed articulations give poor implant survival compared with other options and should not be implanted. All patients with these bearings should be carefully monitored, particularly young women implanted with large diameter heads. Since large diameter ceramic-on-ceramic bearings seem to do well we support their continued use.

FUNDING

National Joint Registry of England and Wales.

Monitoring the introduction and performance of a joint replacement: the United Kingdom metal-on-metal alert

Recent events have made us question our ability to monitor the introduction and performance of a new prosthetic joint replacement. These concerns are mirrored in many other countries, even those with joint registries and other systems for detecting poorly performing implants. In the United Kingdom, as is the case in most European Union countries, we have assessment processes in place, particularly the CE (Conformité Européenne) mark, the National Joint Registry, and the Orthopaedic Data Evaluation Panel. It is important to realize that these organizations can only react to poor performance; it is not within their power as monitoring agencies to prevent a poor implant from entering the market. When an implant has been shown to perform badly, it is referred to the Medicines and Healthcare products Regulatory Agency (MHRA), which then discusses the report with the manufacturer. When it is deemed that there is unequivocal evidence of a serious problem with the implant, the MHRA issues alerts to all hospitals and practitioners. We have continuing concerns about how to assess and monitor modifications to already existing devices. Suggestions are made for improvements to this system, and the authors will welcome feedback.

Clinical outcome using a ligament referencing technique in CAS versus conventional technique

PURPOSE

Computer-assisted surgery (CAS) for total knee arthroplasty (TKA) has become increasingly common over the last decade. There are several reports including meta-analyses that show improved alignment, but the clinical results do not differ. Most of these studies have used a bone referencing technique to size and position the prosthesis. The question arises whether CAS has a more pronounced effect on strict ligamentous referencing TKAs.

METHODS

We performed a prospective cohort study comparing clinical outcome of navigated TKA (43 patients) with that of conventional TKA (122 patients). Patients were assessed preoperatively, and 2 and 12 months postoperatively by an independent study nurse using validated patient-reported outcome tools as well as clinical examination.

RESULTS

At 2 months, there was no difference between the two groups. However, after 12 months, CAS was associated with significantly less pain and stiffness, both at rest and during activities of daily living, as well as greater overall patient satisfaction.

CONCLUSION

The present study demonstrated that computer-navigated TKA significantly improves patient outcome scores such as WOMAC score (P=0.002) and Knee Society score (P=0.040) 1 year after surgery in using a ligament referencing technique. Furthermore, 91% were extremely or very satisfied in the CAS TKA group versus 70% after conventional TKA (P=0.007).

Disinfection by-products in filter backwash water: implications to water quality in recycle designs

The overall purpose of this research was to investigate disinfection by-product (DBP) concentrations and formation potential in filter backwash water (FBWW) and evaluate at bench-scale the potential impact of untreated FBWW recycle on water quality in conventional drinking water treatment. Two chlorinated organic compound groups of DBPs currently regulated in North America were evaluated, specifically trihalomethanes (THMs) and haloacetic acids (HAAs). FBWW samples were collected from four conventional filtration water treatment plants (WTP) in Nova Scotia, Canada, in three separate sampling and plant audit campaigns. THM and HAA formation potential tests demonstrated that the particulate organic material contained within FBWW is available for reaction with chlorine to form DBPs. The results of the study found higher concentrations of TTHMs and HAA9s in FBWW samples from two of the plants that target a higher free chlorine residual in the wash water used to clean the filters (e.g., clearwell) compared to the other two plants that target a lower clear well free chlorine residual concentration. Bench-scale experiments showed that FBWW storage time and conditions can impact TTHM concentrations in these waste streams, suggesting that optimization opportunities exist to reduce TTHM concentrations in FBWW recycle streams prior to blending with raw water. However, mass balance calculations demonstrated that FBWW recycle practice by blending 10% untreated FBWW with raw water prior to coagulation did not impact DBP concentrations introduced to the rapid mix stage of a plant's treatment train.

Total hip arthroplasty in slipped capital femoral epiphysis: a novel technique to remove embedded knowles pins

The Knowles pin has been well recognized in fixing slipped capital femoral epiphysis. When these pins are left in place for a long period, it is very difficult to remove them during total hip arthroplasty, because the pins have fluted threads, which are oversized in the end and allow bone growth in the previously threaded slots. We present a simple and novel technique to remove Knowles pins so that both unnecessary trauma to the lateral femoral cortex and operating time is reduced significantly.

The epidemiology of infertility in the North East of Scotland

BACKGROUND

There is a perception that the prevalence of infertility is on the rise. This study aimed to determine the current prevalence of infertility in a defined geographical population, ascertain changes in self-reported infertility over time and identify risk factors associated with infertility.

METHODS

A postal questionnaire survey of a random population-based sample of women aged 31-50 years was performed in the Grampian region of Scotland. Questions addressed the following areas: pregnancy history, length of time taken to become pregnant each time, whether medical advice had been sought and self-reported exposure to factors associated with infertility.

RESULTS

Among 4466 women who responded, 400 (9.0%) [95% CI 8.1, 9.8] had chosen not to have children. Of the remaining 4066 women, 3283 (80.7%) [95% CI 79.5, 82.0] reported no difficulties in having children and the remaining 783 (19.3%) [95% CI 18.1, 20.5] had experienced infertility, defined as having difficulty in becoming pregnant for more than 12 months and/or seeking medical advice. In total 398 (9.8%) [95% CI 8.9, 10.7] women had primary infertility, 285 (7.0%) [95% CI 6.2, 7.8] had secondary infertility, 100 (2.5%) [95% CI 2.0, 2.9] had primary as well as secondary infertility. A total of 342 (68.7%) and 208 (73.0%) women with primary and secondary infertility, respectively, sought medical advice and 202 (59.1%) and 118 (56.7%) women in each group subsequently conceived. History of pelvic surgery, Chlamydial infection, endometriosis, chemotherapy, long-term health problems and obesity were associated with infertility. In comparison with a similar survey of women aged 46-50 from the same geographical area, the prevalence of both primary infertility (>24 months) [70/1081, (6.5%) versus 68/710 (9.6%) P = 0.02] and secondary infertility [29/1081 (2.7%) versus 40/710 (5.6%) P = 0.002] were significantly lower.

CONCLUSIONS

Nearly one in five women attempting conception sampled in this study experienced infertility, although over half of them eventually conceived. Fertility problems were associated with endometriosis, Chlamydia trachomatis infection and pelvic surgery, as well as obesity, chemotherapy and some long-term chronic medical conditions. There is no evidence of an increase in the prevalence of infertility in this population over the past 20 years.

'Not taken in by media hype': how potential donors, recipients and members of the general public perceive stem cell research

BACKGROUND

Views of embryo donors, scientists and members of the general public on embryonic stem cell research (eSCR) have been widely reported. Less is known about views of potential beneficiaries of stem cell therapy and the influence of media 'hype' on perceptions of eSCR among different groups of stakeholders. This study aimed to examine the perceptions of members of the general public as well as two patient groups likely to benefit from eSCR and to explore the role of the media in shaping these views.

METHODS

A qualitative study carried out in Aberdeen, Scotland included 15 people living with Parkinson's disease (PD), 15 people living with diabetes mellitus (DM), 15 couples with infertility and 21 members of the general public who volunteered for the study. Interview transcripts were analysed thematically using grounded theory.

RESULTS

The two patient groups likely to benefit from eSCR in the future differed in their knowledge (mainly gained from the media) and understanding of eSCR. Those living with PD were older, more debilitated and better informed than those with DM who showed limited interest in potential future benefits of eSCR. Infertile couples learnt about eSCR from health professionals who explained the process of embryo donation to them, and had sought no further information. Most of the general public had accessed information on eSCR and believed themselves to be more discerning than others because of their objectivity, intelligence and 'scientific awareness'. Although, the media and internet were primary sources of information for all except couples with infertility, members of all four groups claimed not to be taken in by the media 'hype' surrounding eSCR.

CONCLUSIONS

Those who expected to benefit from eSCR in the future as well as members of the general public differ in their susceptibility to media 'hype', while believing that they are not taken in by exaggerated claims of benefits. As respondents were a selected group who were not drawn from a representative sample, the findings cannot be generalized to a wider population.

Revision rates after primary hip and knee replacement in England between 2003 and 2006

BACKGROUND

Hip and knee replacement are some of the most frequently performed surgical procedures in the world. Resurfacing of the hip and unicondylar knee replacement are increasingly being used. There is relatively little evidence on their performance. To study performance of joint replacement in England, we investigated revision rates in the first 3 y after hip or knee replacement according to prosthesis type.

METHODS AND FINDINGS

We linked records of the National Joint Registry for England and Wales and the Hospital Episode Statistics for patients with a primary hip or knee replacement in the National Health Service in England between April 2003 and September 2006. Hospital Episode Statistics records of succeeding admissions were used to identify revisions for any reason. 76,576 patients with a primary hip replacement and 80,697 with a primary knee replacement were included (51% of all primary hip and knee replacements done in the English National Health Service). In hip patients, 3-y revision rates were 0.9% (95% confidence interval [CI] 0.8%-1.1%) with cemented, 2.0% (1.7%-2.3%) with cementless, 1.5% (1.1%-2.0% CI) with "hybrid" prostheses, and 2.6% (2.1%-3.1%) with hip resurfacing (p < 0.0001). Revision rates after hip resurfacing were increased especially in women. In knee patients, 3-y revision rates were 1.4% (1.2%-1.5% CI) with cemented, 1.5% (1.1%-2.1% CI) with cementless, and 2.8% (1.8%-4.5% CI) with unicondylar prostheses (p < 0.0001). Revision rates after knee replacement strongly decreased with age.

INTERPRETATION

Overall, about one in 75 patients needed a revision of their prosthesis within 3 y. On the basis of our data, consideration should be given to using hip resurfacing only in male patients and unicondylar knee replacement only in elderly patients.

Effect of hormonal growth promotants on palatability and carcass traits of various muscles from steer and heifer carcasses from a Bos indicus - Bos taurus composite cross

The effect of several different hormonal growth promotant (HGP) implant strategies on the palatability and carcass traits of different muscles in beef carcasses was investigated using samples from heifer and steer carcasses from a Bos indicus composite breed. In experiment 1, there were seven different implant strategies evaluated in heifers that were given different combinations of up to three implants (implanted at weaning, during backgrounding and at feedlot entry). A total of 112 heifers were slaughtered and 11 muscles or portions were collected from both sides [Mm. adductor femoris, gracilus, semimembranosus, longissimus dorsi lumborum, triceps brachii caput longum, semispinalis capitis, serratus ventralis cervicis, spinalis dorsi, biceps femoris (syn. gluteobiceps), tensor fasciae latae, gluteus medius (both the ‘D’ and the ‘eye’ portions) rectus femoris, vastus intermedius, vastus lateralis and vastus medialis]. These muscles were used to prepare a total of 1030 sensory samples which were aged for either 7 or 21 days and frozen. Thawed samples were cooked using different cooking methods (grill, roast and stir frying) before being evaluated by a consumer taste panel that scored samples for tenderness, juiciness, like flavour and overall liking. Experiment 2 used the steer portion from the same calving, which were treated to a similar array of HGP strategies, except that they were given up to four implants between weaning and slaughter at ~3 years of age. In experiment 2, there was a total of 12 different HGP implant strategies tested. At boning, three muscles (Mm. psoas major, longisimuss dorsi thoracis and lumborum portions) were collected from each of 79 carcasses with a total of 237 steak samples that consumers tested as grilled steaks. For both experiments, the mean of the HGP implant strategies resulted in increased ossification scores (P < 0.05) and decreased marbling scores (P < 0.05) compared with the controls, with the effect on ossification being much larger in the older steer groups. In both experiments, the different HGP strategies decreased (P < 0.05) all sensory scores compared with the controls, for all cooking method and muscle combinations. In experiment 1, there was no interaction between the mean HGP effect and muscle (P > 0.05), and aging rates differed among the muscles (P < 0.05). In experiment 2, there was a significant (P < 0.05) muscle × HGP treatment interaction, with a decrease in tenderness score due to HGP implant strategies in the M. longisimuss thoracis and lumborum portions, compared with no significant effect in the M. psoas major. For both experiments, there were no significant differences among the different implantation strategies on sensory scores (P > 0.05).

Evolution of the Meat Standards Australia (MSA) beef grading system

The Australian Beef Industry identified variable eating quality as a major contributor to declining beef consumption in the early 1990s and committed research funding to address the problem. The major issue was the ability to predict the eating quality of cooked beef before consumption. The Meat Standards Australia (MSA) program developed a consumer testing protocol, which led to MSA grading standards being defined by consumer score outcomes. Traditional carcass grading parameters proved to be of little value in predicting consumer outcomes. Instead a broader combination of factors forms the basis of an interactive prediction model that performs well. The grading model has evolved from a fixed parameter ‘Pathway’ approach, to a computer model that predicts consumer scores for 135 ‘cut by cooking method’ combinations for each graded carcass. The body of research work conducted in evaluating critical control points and in developing the model predictions and interactions has involved several Australian research groups with strong support and involvement from the industry.

Consumer assessment of eating quality - development of protocols for Meat Standards Australia (MSA) testing

Meat Standards Australia sought a consistent measure of the beef eating experience to the consumer. Rather than objective measurements or trained panel sensory assessment, it was decided to proceed with direct consumer assessment. Consumer-based assessment has much greater variation, but it has the decided advantage of validity. This paper summarises the path taken to obtain consistent consumer assessment. What meat samples to present to consumers? What responses to ask for? What to do with these responses when they were obtained? The answers to these questions have led to the MQ4 measure of consumer assessment of meat eating quality, which now forms the basis of the MSA predictive model.

Effect of repeated implants of oestradiol-17β on beef palatability in Brahman and Braham cross steers finished to different market end points

The effect of repeated implantation with 20 mg oestradiol-17β (Compudose 100) on carcass and meat quality traits was investigated using 478 Bos indicus and B. indicus × Bos taurus cross steers finished on either pasture or grain to achieve carcass weight for one of three market end points (domestic, 220 kg; Korean, 280 kg; or Japanese, 340 kg). In the oestradiol-17β treatment group, animals were administered implants at ~100-day intervals, with the number of implants administered to any steer ranging from one to eight. Cattle were slaughtered and at boning the anterior portion of the M. longissimus lumborum was removed and frozen after aging for 1 day for later objective meat quality measurements (shear force, compression and cook loss %). The adjoining portion was aged for 14 days before consumer sensory testing using the Meat Standards Australia protocols. Each sample was scored for tenderness, juiciness, like flavour and overall liking by 10 untrained consumers. Implanting increased carcass weights and ossification scores (P < 0.05) and reduced marbling scores in comparison to non-implanted carcasses. For tenderness, like flavour, overall liking and MQ4 scores there was a significant (P < 0.05) interaction between B. indicus content and oestradiol-17β treatment, whereby high B. indicus content cattle that were implanted with oestradiol-17β had the lowest sensory scores. The number of implants administered did not affect carcass weights or marbling scores, whereas ossification scores increased in carcasses as the number of implants increased. The number of implants administered had no effect (P > 0.05) on sensory scores, or objective meat tenderness.

The use of telemedicine to care for cancer patients at remote sites

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Background: At the BC Cancer Agency -CSI we are challenged to provide systemic cancer care to a population of 720,000 widely dispersed over 250,000 square kilometers. Video-link technology (VT) has been used at our centre since April 2004 to help provide distant care and prevent patient and physician travel. Methods: Patients gave consent for the use of VT. We prospectively collected data on patient and physician experiences as part of on-going quality assurance. We retrospectively collected the clinical data on these patients. Results: We performed 104 encounters on 100 patients between April 2, 2004 and October 4, 2006. Patient characteristics: female 62%, male 38%, average age was 66 years with a range of 28 –83. Extent of cancer was 67% curable, 31% advanced and 7% unknown. Visit type and cancer sites are shown below. Patients rated this experience very highly and the vast majority would repeat the experience rather than travel or wait several weeks to see the doctor in person. Physicians were not as satisfied as the patients; and both groups expressed a concern about the need for physical exam. In those having a consult, 54% had an exam within 60 days, and in none of these patients were the treatment recommendations changed. The majority (57%) of those consult patients that didn’t have an exam had either Stage 0 or I breast cancer or Stage II or III colorectal cancer; and it seems unlikely that physical exam would have changed management in these patients. Conclusions: We were able to deliver cancer care at distant sites with VT and patients found the experience very acceptable. There may not be a need for repeat physical exam in these patients, who had previously been examined by other physicians, prior to referral.

No significant financial relationships to disclose.

[Table: see text]

The association of scapho-trapezio-trapezoid osteoarthrosis and scapholunate dissociation

There are two parts to this paper. In the first part we report 18 cases of bilateral scapho-trapezio-trapezoid osteoarthrosis associated with uni- or bilateral scapholunate dissociation. This case series was followed prospectively using repeat clinical assessments and radiographs. We were able to document the progression of both the clinical manifestations and radiographic features of the scapholunate dissociation in these patients. In the second part of the paper we compared the radiographic indices of scapholunate dissociation seen in our series, that is, the scapholunate angle and interval, with those of a control group over time, to determine if there was a significant difference. The control group differed from our series principally by being devoid of any clinical or radiographic evidence of scapho-trapezio-trapezoid osteoarthrosis. We found that our case series already had some radiographic evidence of scapholunate attrition at presentation and that at follow-up the scapholunate dissociation became more pronounced both clinically and radiographically relative to the controls. The authors propose a theory to explain the association and temporal relationship between the two conditions.

Anaesthesia for caesarean section in a patient with diastrophic dwarfism

Diastrophic dwarfism is a rare disease in which pregnancy is uncommon. In this report we present a woman with diastrophic dwarfism who underwent caesarean section under epidural anaesthesia. Her care was successfully managed with multidisciplinary team planning. The total dose of local anaesthetic needed for epidural block was greater than the doses reported for achondroplastic dwarfism.

Major problems and key issues in Maternal Health in Nepal

This paper highlights some of the challenges facing maternal health in Nepal and to suggest possible solutions for improvements. Key literature from across the globe is reviewed and discussed in a Nepalese context. Maternal mortality remains one of the biggest public health problems in Nepal. Lack of access to basic maternal healthcare, difficult geographical terrain, poorly developed transportation and communication systems, poverty, illiteracy, women's low status in the society, political conflict, shortage of health care professional and under utilization of currently available services are major challenges to improving maternal health in Nepal. In order to effect real improvements in maternal health, attention needs to be focused both on biomedical and social interventions. Improving health facilities, mother's nutrition, women's position in the society such as freedom of movement, providing education to female children, integrating Traditional Birth Attendants into local health services can play a vital role in the improvement of mothers' health.