Cancer incidence in Finnish hip replacement patients from 1980 to 1995: a nationwide cohort study involving 31,651 patients

An Update on Implant-Associated Malignancies and Their Biocompatibility

Implanted medical devices are widely used across various medical specialties for numerous applications, ranging from cardiovascular supports to orthopedic prostheses and cosmetic enhancements. However, recent observations have raised concerns about the potential of these implants to induce malignancies in the tissues surrounding them. There have been several case reports documenting the occurrence of cancers adjacent to these devices, prompting a closer examination of their safety. This review delves into the epidemiology, clinical presentations, pathological findings, and hypothesized mechanisms of carcinogenesis related to implanted devices. It also explores how the surgical domain and the intrinsic properties and biocompatibility of the implants might influence the development of these rare but serious malignancies. Understanding these associations is crucial for assessing the risks associated with the use of medical implants, and for developing strategies to mitigate potential adverse outcomes.

A prospective study on cancer risk after total hip replacements for 41,402 patients linked to the Cancer registry of Norway

BACKGROUND

Concerns have been raised that implants used in total hip replacements (THR) could lead to increased cancer risk. Several different materials, metals and fixation techniques are used in joint prostheses and different types of articulation can cause an increased invasion of particles or ions into the human body.

METHODS

Patients with THR registered in the Norwegian Arthroplasty Register during 1987-2009 were linked to the Cancer registry of Norway. Patients with THR due to osteoarthritis, under the age of 75 at time of surgery, were included. Standardized incidence ratios (SIR) were applied to compare cancer risk for THR patients to the general population. Types of THR were divided into cemented (both components), uncemented (both components), and hybrid (cemented femoral and uncemented acetabular components). To account for selection mechanisms, time dependent covariates were applied in Cox-regression, adjusting for cancer risk the first 10 years after surgery. The analyses were adjusted for age, gender and if the patient had additional THR-surgery in the same or the opposite hip. The study follows the STROBE guidelines.

RESULTS

Comparing patients with THR to the general population in Norway we found no differences in cancer risk. The overall SIR for the THR-patients after 10 years follow-up was 1.02 (95% CI: 0.97-1.07). For cemented THR, the SIR after 10 years follow-up was 0.99 (95% CI: 0.94-1.05), for uncemented, 1.16 (95% CI: 1.02-1.30), and for hybrid 1.12 (95% CI: 0.91-1.33). Adjusted Cox analyses showed that patients with uncemented THRs had an elevated risk for cancer (hazard ratio: HR = 1.24, 95% CI: 1.05-1.46, p = 0.009) when compared to patients with cemented THRs after 10 years follow-up. Stratified by gender the increased risk was only present for men. The risk for patients with hybrid THRs was not significantly increased (HR = 1.07, 95% CI: 0.85-1.35, p = 0.55) compared to patients with cemented THRs.

CONCLUSIONS

THR patients had no increased risk for cancer compared to the general population. We found, however, that receiving an uncemented THR was associated with a small increased risk for cancer compared to cemented THR in males, but that this may be prone to unmeasured confounding.

No generally increased risk of cancer after total hip arthroplasty performed due to osteoarthritis

Previous studies on the risk of cancer after total hip arthroplasty (THA) contradict each other, and many are hampered by small cohort sizes, residual confounding, short observation times or a mix of indications underlying the THA procedure. We evaluated the risk of cancer after total hip arthroplasty due to osteoarthritis in a nationwide cohort by comparing cancer incidences in individuals exposed to total hip arthroplasty due to osteoarthritis and in unexposed, sex-, age- and residence matched individuals. To address some previous studies' shortcomings, information on comorbidity and socioeconomic background were obtained and adjusted for. We included 126,276 patients exposed to a cemented THA between 1992 and 2012, and 555,757 unexposed individuals. Follow-up started on the day of surgery for exposed individuals and respective date for matched, unexposed individuals, and ended on the day of death, emigration, censuring or December 31st, 2012, whichever came first. The Swedish Hip Arthroplasty Registry (SHAR), the Swedish Cancer Registry, the Swedish National Patient Registry and Statistics Sweden were accessed to obtain information on procedural details of the THA, cancer diagnoses, comorbidities, and socioeconomic background. The primary outcome measure was the occurrence of any cancer after the index date. Exposed individuals had a slightly lower adjusted risk of developing any cancer than unexposed individuals (hazard ratio [HR] 0.97; CI 0.95-0.99). The only cancer with a statistically significant risk increase in exposed individuals was skin melanoma (HR 1.15; CI 1.05-1.24). We attained similar risk estimates in analyses stratified by sex, in individuals with minimum 5 years of follow-up, in an analysis including individuals with a history of previous cancer, and in patients with cementless THA. In this study on a large and well-defined population with long follow-up, we found no increased overall risk of cancer after THA. These reassuring findings could be included in the guidelines on preoperative information given to THA patients.

Risk of cancer after primary total hip replacement: The influence of bearings, cementation and the material of the stem

Background and purpose - Despite the increasing number of total hip replacements (THRs), their systemic influence is still not known. We have studied the influence of specific features of THRs-the bearing surface, the use of bone cement and the material of the stem-on the cancer incidence. Patients and methods - In a retrospective cohort study we identified 8,343 patients with THRs performed at Valdoltra Hospital from September 1, 1997 to December 31, 2009. Patient data were linked to national cancer and population registries. The standardized incidence ratios (SIR) and Poisson regression relative risks (RR) were calculated for all and specific cancers. Results - General cancer risk in our cohort was comparable to the population risk. Comparing with population, the risk of prostate cancer was statistically significantly higher in patients with metal-on-metal bearings (SIR =1.35); with metal-on-polyethylene bearings (SIR =1.30), with non-cemented THRs (SIR =1.40), and with titanium alloy THRs (SIR =1.41). In these last 3 groups there was a lower risk of hematopoietic tumors (SIR =0.69; 0.66 and 0.66 respectively). Risk of kidney cancer was significantly higher in the non-metal-on-metal, non-cemented, and titanium alloy groups (SIR =1.30; 1.46 and 1.41 respectively). Risk of colorectal and lung cancer was significantly lower in the investigated cohort (SIR =0.82 and 0.83, respectively). Risk for all cancers combined as well as for prostate and skin cancer, shown by Poisson analysis, was higher in the metal-on-metal group compared with non-metal-on-metal group (RR =1.56; 2.02 and 1.92, respectively). Interpretation - Some associations were found between the THRs' features, especially a positive association between metal-on-metal bearings, and specific cancers.

Development of malignant lymphoma after metal-on-metal hip replacement: a case report and review of the literature

A number of previous studies have reported a potential risk of malignancy, particularly hematological malignancy, developing in patients receiving a metal-on-metal (MoM) hip replacement. We report a case of malignant lymphoma that arose in a patient who had an MoM hip arthroplasty complicated by development of a pseudotumour. The tumour was a B cell follicular lymphoma that involved lymph nodes and bone. Metal ions are known to have a genotoxic effect on lymphoid cells. Although epidemiological studies have not established that there is an increased risk of lymphoma associated with MoM implants, only a relatively short time period has elapsed since re-introduction of this type of implant and long-term follow-up of patients with MoM implants is indicated.

Cobalt toxicity in humans-A review of the potential sources and systemic health effects

Cobalt (Co) and its compounds are widely distributed in nature and are part of numerous anthropogenic activities. Although cobalt has a biologically necessary role as metal constituent of vitamin B₁₂, excessive exposure has been shown to induce various adverse health effects. This review provides an extended overview of the possible Co sources and related intake routes, the detection and quantification methods for Co intake and the interpretation thereof, and the reported health effects. The Co sources were allocated to four exposure settings: occupational, environmental, dietary and medical exposure. Oral intake of Co supplements and internal exposure through metal-on-metal (MoM) hip implants deliver the highest systemic Co concentrations. The systemic health effects are characterized by a complex clinical syndrome, mainly including neurological (e.g. hearing and visual impairment), cardiovascular and endocrine deficits. Recently, a biokinetic model has been proposed to characterize the dose-response relationship and effects of chronic exposure. According to the model, health effects are unlikely to occur at blood Co concentrations under 300μg/l (100μg/l respecting a safety factor of 3) in healthy individuals, hematological and endocrine dysfunctions are the primary health endpoints, and chronic exposure to acceptable doses is not expected to pose considerable health hazards. However, toxic reactions at lower doses have been described in several cases of malfunctioning MoM hip implants, which may be explained by certain underlying pathologies that increase the individual susceptibility for Co-induced systemic toxicity. This may be associated with a decrease in Co bound to serum proteins and an increase in free ionic Co²⁺. As the latter is believed to be the primary toxic form, monitoring of the free fraction of Co²⁺ might be advisable for future risk assessment. Furthermore, future research should focus on longitudinal studies in the clinical setting of MoM hip implant patients to further elucidate the dose-response discrepancies.

The taper disaster--how could it happen?

Corrosion of metallic implants in contact with body fluids is unavoidable, especially at interfaces where movement occurs or in gaps. Corrosion became clinically relevant with the introduction of large modular metal-on-metal total hip joint articulations (MoM THA) early in the 21st century. This review attempts to summarise the scientific knowledge about taper problems available at the time of introduction of these bearings, why this "disaster" could happen. It is speculated that changes to the taper connection made in the 1990s to increase the range of motion with small heads (28 and 32 mm) reduced the mechanical strength of this connection, which did not matter for small heads. With the use of large and very large metal heads in MoM articulations, which have a larger lever arm and can generate high friction in unfavourable situations, suddenly the taper interface exhibited corrosion problems on a previously unknown scale. It is speculated that due to the higher mechanical loading with larger heads, the taper connection became less forgiving with respect to assembly conditions, contamination, manufacturing tolerances and other factors, which are yet not known. Since no major clinical problems had been reported before the introduction of these bearings and the pre-clinical testing was very successful, the disaster took its course. The patient-implant-surgeon system is a very complex intrinsically hazardous system. Pre-clinical testing addresses few and defined factors and such, good results cannot be directly transferred to the clinical reality. A controlled stepwise introduction of innovations is required.

Etiologic, environmental and inherited risk factors in sarcomas

Sarcomas are a rare group of mesenchymal tumors affecting a younger population. The etiology remains unknown in most cases. Environmental factors that increase sarcoma risk include radiation exposure and chemical carcinogens. Several familial cancer syndromes confer sarcoma predisposition, such as the Li-Fraumeni Syndrome (LFS). In this increasingly genomic focussed era of medicine, it will be clinically important to understand the genetic basis of sarcoma risk.

Anaplastic large cell lymphoma (ALCL) and breast implants: breaking down the evidence

Systemic anaplastic large cell lymphoma (ALCL) is a distinct disease classification provisionally sub-divided into ALCL, Anaplastic Lymphoma Kinase (ALK)(+) and ALCL, ALK(-) entities. More recently, another category of ALCL has been increasingly reported in the literature and is associated with the presence of breast implants. A comprehensive review of the 71 reported cases of breast implant associated ALCL (iALCL) is presented indicating the apparent risk factors and main characteristics of this rare cancer. The average patient is 50 years of age and most cases present in the capsule surrounding the implant as part of the periprosthetic fluid or the capsule itself on average at 10 years post-surgery suggesting that iALCL is a late complication. The absolute risk is low ranging from 1:500,000 to 1:3,000,000 patients with breast implants per year. The majority of cases are ALK-negative, yet are associated with silicone-coated implants suggestive of the mechanism of tumorigenesis which is discussed in relation to chronic inflammation, immunogenicity of the implants and sub-clinical infection. In particular, capsulotomy alone seems to be sufficient for the treatment of many cases suggesting the implants provide the biological stimulus whereas others require further treatment including chemo- and radiotherapy although reported cases remain too low to recommend a therapeutic approach. However, CD30-based therapeutics might be a future option.

The imaging prevalence of osteolytic metastasis or multiple myeloma presenting as a periprosthetic lucency in the hip

OBJECTIVE

The purpose of this article is to determine how often a malignant process presents as a lucency near a hip prosthesis, and to classify the frequency and distribution of differential diagnoses of these lytic lesions, and to determine their disposition.

MATERIALS AND METHODS

Hip and pelvis imaging examinations obtained from January 1998 to June 2008 were text searched (1,164,560 reports) to identify patients with hip prostheses (3508 patients); the records were then searched and individually reviewed to identify periprosthetic lucency (2036 reports; 176 patients). The most likely cause for the lucency, as determined by the interpreting radiologist, was recorded. Malignancy was confirmed in all cases. Malignancy was excluded by biopsy for some patients but by clinical follow-up or at the time of revision, if performed, for most patients. Prevalence rates and 95% CIs were calculated.

RESULTS

The overall prevalence of periprosthetic lucency was 5.02%. The prospective diagnoses suggested included loosening or infection (37.5%), degenerative cysts (19.3%), metastases (23.3%), multiple myeloma (14.8%), and metastasis of previously unknown malignancy (3.4%). The prevalence of metastases or multiple myeloma near a hip prosthesis was 1.54%; however, each of these patients had a known prior diagnosis of bone metastases, multiple myeloma, or primary bone malignancy.

CONCLUSION

Among the 2036 examinations with periprosthetic lucency, there were no instances of new malignancy, metastasis, or myeloma. These results suggest that it is statistically unlikely that a lucency near a hip prosthesis represents the first presentation of malignancy or metastases, regardless of how large or aggressive it may appear on imaging.

Patterns of risk of cancer in patients with metal-on-metal hip replacements versus other bearing surface types: a record linkage study between a prospective joint registry and general practice electronic health records in England

Background

There are concerns that metal-on-metal hip implants may cause cancer. The objective of this study was to evaluate patterns and timing of risk of cancer in patients with metal-on-metal total hip replacements (THR).

Methods

In a linkage study between the English National Joint Registry (NJR) and the Clinical Practice Research Datalink (CPRD), we selected all THR surgeries (NJR) between 2003 and 2010 (n = 11,540). THR patients were stratified by type of bearing surface. Patients were followed up for cancer and Poisson regression was used to derive adjusted relative rates (RR).

Results

The risk of cancer was similar in patients with hip resurfacing (RR 0.69; 95% Confidence Interval [CI] 0.39–1.22) or other types of bearing surfaces (RR 0.96; 95% CI 0.64–1.43) compared to individuals with stemmed metal-on-metal THR. The pattern of cancer risk over time did not support a detrimental effect of metal hip implants. There was substantial confounding: patients with metal-on-metal THRs used fewer drugs and had less comorbidity.

Conclusions

Metal-on-metal THRs were not associated with an increased risk of cancer. There were substantial baseline differences between the different hip implants, indicating possibility of confounding in the comparisons between different types of THR implants.

Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip: a retrospective cohort study in Scotland

Background:

Release and dispersion of particles arising from corrosion and wear of total hip arthroplasty (THA) components has raised concerns about a possible increased risk of cancer. Concerns have been heightened by a recent revival in the use of metal-on-metal (MoM) hip prostheses.

Methods:

From a linked database of hospital discharge, cancer registration, and mortality records, we selected a cohort of patients who underwent primary THA (1990–2009) or primary resurfacing arthroplasty (mainly 2000–2009) in Scotland, with follow-up to the end of 2010. Available operation codes did not enable us to distinguish MoM THAs. Indirectly standardised incidence ratios (SIRs) were calculated for selected cancers with standardisation for age, sex, deprivation, and calendar period.

Results:

The study cohort included 71 990 patients yielding 547 001 person-years at risk (PYAR) and 13 946 cancers diagnosed during follow-up. For the total period of observation combined, the risks of all cancers (SIR: 1.05; 95% CI: confidence interval 1.04–1.07), prostate cancer (SIR: 1.07; 95% CI: 1.01–1.14), and multiple myeloma (SIR: 1.22; 95% CI: 1.06–1.41) were increased. These modest increases in risk emerged in the context of effectively multiple tests of statistical significance, and may reflect inadequate adjustment for confounding factors. For 1317 patients undergoing primary resurfacing arthroplasty between 2000 and 2009 (PYAR=5698), the SIR for all cancers (n=39) was 1.23 (95% CI: 0.87–1.68).

Conclusion:

In the context of previous research, these results do not suggest a major cause for concern. However, the duration of follow-up of patients receiving recently introduced, new-generation MoM prostheses is too short to rule out a genuinely increased risk of cancer entirely.

Risk of cancer with metal-on-metal hip replacements: population based study

OBJECTIVE

To assess the risk of cancer associated with modern primary metal-on-metal hip replacements.

DESIGN

Population based study.

SETTING

Nationwide retrospective comparative register.

PARTICIPANTS

10,728 patients who underwent metal-on-metal total hip arthroplasty and 18,235 patients who underwent conventional metal-on-polyethylene, ceramic-on-polyethylene, and ceramic-on-ceramic total hip arthroplasty (the non-metal-on-metal cohort) in the Finnish Arthroplasty Register 2001-10. Data on cancer cases up to 2010 for these cohorts were extracted from the Finnish Cancer Registry.

MAIN OUTCOME MEASURES

The relative risk of cancer was expressed as the ratio of observed to expected number of cases from the Finnish population--that is, the standardised incidence ratio. The relative risk of cancer in the metal-on-metal cohort compared with the non-metal-on-metal cohort was estimated with analyses of these ratios and Poisson regression.

RESULTS

The overall risk of cancer in patients with metal-on-metal hip implants was similar to that in the Finnish population (378 observed v 400 expected, standardised incidence ratio 0.95, 95% confidence interval 0.85 to 1.04). The overall risk of cancer in patients with metal-on-metal hip implants was also no higher than in patients who had received non-metal-on-metal hip implants (relative risk 0.92, 0.81 to 1.05).

CONCLUSIONS

Metal-on-metal hip replacements are not associated with an increased overall risk of cancer during a mean follow-up of four years.

Malignant fibrous histiocytoma at the site of an alumina-on-alumina-bearing total hip arthroplasty mimicking infected trochanteric bursitis

Although the incidence of malignant tumors in patients undergoing total hip arthroplasties (THAs) is known to be lower than the general population, there exist several reports on the development of malignant tumors at the site of THAs. We report another case of malignant fibrous histiocytoma at the site of a THA, which was developed in an older patient who presented a cystic mass around the total hip prosthesis using a ceramic-on-ceramic bearing system, even without evidence of osteolysis or loosening of implants. This is the second case associated with an aluminum oxide prosthesis in English literature.

Cementless large-head metal-on-metal total hip arthroplasty in patients younger than 60 years--a multicenter early result

Large-head metal-on-metal total hip arthroplasty has the theoretical advantages of less wear and better range of motion than traditional polyethylene bearings and seems to be a better choice for young and active patients. We conducted a retrospective study and reported the early results of using such prostheses in 59 patients (70 hips) with a mean age of 43.1 years (range, 23-59 years) at the time of surgery. Osteonecrosis of the femoral head accounted for most diagnoses. Harris Hip Scores and hip range of motion both significantly improved (p<0.001) at an average follow-up of 32.6 months (range, 24-48 months). Only one intraoperative calcar fissure was encountered, and it was fixated by cerclage wiring; there was no infection, dislocation, or osteolysis around either the cup or the stem at the latest follow-up. A postoperative gap in the acetabular component was noted in 24 hips, with a mean depth of 1.11 mm, but this was not correlated with the functional score (p=0.291). Transient thigh pain, which resolved after 6 months, was observed in six patients but was not related to either the postoperative gap or cup inclination (p=1.000 and p=0.664, respectively). All patients resumed their original jobs and recreational activities with little discomfort. Thus far, large-head metal-on-metal total hip arthroplasty has shown excellent early results. The long-term results and the effects of metal debris and potentially elevated serum metal ion levels require further observation.

Origins of injection-site sarcomas in cats: the possible role of chronic inflammation-a review

The etiology of feline injection-site sarcomas remains obscure. Sarcomas and other tumors are known to be associated with viral infections in humans and other animals, including cats. However, the available evidence suggests that this is not the case with feline injection-site sarcomas. These tumors have more in common with sarcomas noted in experimental studies with laboratory animals where foreign materials such as glass, plastics, and metal are the causal agent. Tumors arising with these agents are associated with chronic inflammation at the injection or implantation sites. Similar tumors have been observed, albeit infrequently, at microchip implantation sites, and these also are associated with chronic inflammation. It is suggested that injection-site sarcomas in cats may arise at the administration site as a result of chronic inflammation, possibly provoked by adjuvant materials, with subsequent DNA damage, cellular transformation, and clonal expansion. However, more fundamental research is required to elucidate the mechanisms involved.

Severe osteolysis and soft tissue mass around total hip arthroplasty: description of four cases and review of the literature with respect to clinico-radiographic and pathologic differential diagnosis

Periprosthetic osteolysis is a well known phenomenon caused by wear particle-induced bone resorption, particularly common and extensively reported in total hip arthroplasty. Its typical radiographic feature is a radiolucent area adjacent to an implant, sometimes associated with a soft tissue mass. Osteolytic changes may be caused by numerous other pathologic processes, including infection, metabolic disease, and neoplasia. Four cases of massive periprosthetic bone destruction associated with a large soft tissue mass around a failed total hip replacement are presented. In three cases, a diagnosis of periprosthetic osteolysis was correctly made and managed by revision surgery. However, in one case angiosarcoma of the ipsilateral hemipelvis went long unrecognized despite aggressive clinical course, requiring hind-quarter amputation and ultimately resulting in the patient's death. Periprosthetic malignancy in the form of either primary sarcoma or metastatic cancer is a very rare yet reported event in the setting of previous hip replacement, likely leading to catastrophic consequences when diagnosis is not established in a timely manner. The differential diagnosis of periprosthetic osteolysis should consider the entire spectrum of conditions that can present with radiolucent changes. Thorough review of patient's history and course of symptoms, along with careful evaluation of standard roentgenograms should be always performed and possibly integrated with imaging modalities such as CT, MRI, and bone scintigraphy in order to increase diagnostic accuracy. If uncertainty remains, biopsy should always be considered to rule out malignancy.

Postmortem study of femoral osteolysis associated with metal-on-metal articulation in total hip replacement: an analysis of nine cases

BACKGROUND

Improved metal-on-metal articulations were reintroduced in total hip replacement to avoid the osteolysis sometimes seen with conventional ultra-high molecular weight polyethylene bearings. Osteolysis and local lymphocytic infiltration have been reported at revision of some metal-on-metal devices. We report similar and additional results in a study of second-generation metal-on-metal hip implants retrieved post mortem.

METHODS

Components and surrounding tissues were collected post mortem from seven patients with nine total hip replacements (Zweymüller SL stem with an Alloclassic cup) with Metasul metal-on-metal articulations. All available patient information was recorded. Radiographs of the hips were evaluated for osteolysis. Sections of joint capsule as well as of the femoral implant with surrounding bone were reviewed, and energy-dispersive x-ray analysis was used to evaluate the composition of wear products. The amount of wear was measured for each component (nine femoral heads and eight cup inserts), when possible, by a coordinate measurement machine with use of the dimensional method.

RESULTS

The patients died between three and ten years after arthroplasty, and six of the seven were asymptomatic at the time of death. One patient, with the highest rate of total wear (i.e., wear of femoral head and acetabular cup; 7.6 microm/yr), had increasing hip pain for one year, and histological analysis confirmed the radiographic findings of osteolysis. For two other patients, histological analysis confirmed the radiographic findings of asymptomatic osteolysis. For three patients, histological analysis revealed osteolysis that had escaped conventional radiographic analysis. Joint capsule tissue showed evidence of metallosis in all hips and local lymphocytic infiltration in eight hips. Energy-dispersive x-ray analysis revealed elements attributable to CoCrMo alloy in all hips and traces of corrosion products in three hips.

CONCLUSIONS

The postmortem findings of osteolysis and/or lymphocytic infiltration associated with eight clinically well-functioning, low wear devices (a total wear rate of <4 microm/yr) suggest there may be frequent, unappreciated femoral bone loss and local immunological response in patients with second-generation metal-on-metal hip implants. Compared with previous postmortem studies, our findings showed the extent of osteolysis was similar to that with metal-on-polyethylene articulations.

Metastasis development at the site of cervical spine arthrodesis

Biologically, the site of arthrodesis provides a microenvironment replete of growth factors and active remodeling, which is propitious for bone regrowth. There is a theoretical possibility though that this microenvironment would also provide a fertile site for metastatic deposits to occur. Although spinal fusion with various types of instrumentation is commonly used to treat various disorders, development of tumors at the site of spinal arthrodesis has not been previously reported. We present the clinical, radiographic, and pathological features of a case of previously undiagnosed metastatic adenocarcinoma, occurring 1 year following anterior arthrodesis and fusion for cervical spondylotic myelopathy at the C3-C4 level. The patient's initial radiologic presentation suggested an epidural abscess with osteomyelitic destruction of C3 and C4. Our report alerts surgeons to the possibility that metastasis may occur at the site of a previous spinal arthrodesis.

Cancer risk is not increased after conventional hip arthroplasty

BACKGROUND AND PURPOSE

Wear debris from conventional total hip arthroplasty (THA) induces chromosomal aberrations and DNA damage, which may promote cancerogenesis. A long latent period is required for solid tumors. We therefore re-analyzed a large THA cohort for cancer.

PATIENTS AND METHODS

We updated a cohort of 24,636 patients with primary osteoarthritis and metal-on-polyethylene THA who had been entered in the Finnish Arthroplasty Register between 1980 and 1995, and linked it to the Finnish Cancer Registry for cancer risk assessment up to 2005. The mean follow-up time was 13 years. The numbers of cancer cases observed were compared with expected rates based on incidence in the general population.

RESULTS

The standardized incidence ratio (SIR) for the whole follow-up period was 0.95 (95% confidence interval (CI): 0.92-0.97). After 10 years of follow-up, the SIR was equal to that in the normal population (SIR = 0.98, 95% CI: 0.94-1.03). Incidence of lung cancer was low throughout the follow-up time and that of prostate cancer was slightly elevated. The incidence rates for all other forms of cancer did not deviate significantly from those in the normal population.

INTERPRETATION

We found no increased cancer risk in patients with conventional THA after an average of 13 years and up to 25 years of follow-up.

Angiosarcoma around a revision total hip arthroplasty and review of literature

Development of cancer in association with metallic implants is well recognized yet poorly understood. We report a case of angiosarcoma at the site of a revision total hip arthroplasty. We found only 3 previous reports on angiosarcoma associated with hip arthroplasty in English literature. Association between malignant tumor and hip arthroplasty deserves attention because this surgical procedure is so common that possible risk of a neoplasm should be quantified. Sarcoma is rare, and its possible causation by retained foreign body material has been reported only as single cases.

A left knee wound complication by non-Hodgkins lymphoma in bilateral total knee arthroplasties

A 70-year-old woman with a history of bilateral primary knee osteoarthritis presented with a left knee wound complication, a non-Hodgkins lymphoma, after bilateral total knee arthroplasties. After exploring several etiologies, the evidence in this unusual case suggests a coincidental preexisting lymphoma.

Levels of systemic metal ions in patients with intramedullary nails

BACKGROUND

It is being increasingly recognized that orthopedic implants are associated with adverse tissue responses, mediated by degradation products. Recent interest has been focused on the production of metal ions from hip arthroplasty. Few studies have reviewed fracture fixation devices and their metal ion production.

METHODS

61 subjects were enlisted into the study, with 3 subgroups. 21 subjects had Russell-Taylor intramedullary tibial nails in situ for 26 (21-32) months (316LVm stainless steel), 20 subjects had TriGen intramedullary tibial nails in situ for 43 (35-51) months (Ti-6Al-4V titanium alloy), and the remaining 20 subjects did not have any implant in situ and served as controls. Blood samples were taken and serum chromium, molybdenum, titanium, aluminium, and vanadium concentrations were measured using inductively coupled plasma (ICP) techniques.

RESULTS

The 3 groups were matched for age, sex, and BMI. The subjects with Russell-Taylor nails had elevated levels of chromium (0.10 microg/L) with median concentrations 2.5 times higher than those of the control group. The subjects with TriGen nails had less significantly elevated levels of titanium (6.5 microg/L).

INTERPRETATION

Stainless steel implants show significant differences from titanium implants in the dissemination of metal ions. Although the levels of chromium were elevated, the overall levels were modest when compared to published data regarding metal ion release and hip arthroplasty. Intramedullary nails are, however, often used in younger patients. If not removed, they may result in prolonged exposure to metal ions.

Metal-on-metal total hip arthroplasty

Although metal-on-metal total hip arthroplasty (MOM THA) has been used for over 3 decades, substantial improvements in manufacturing and design have led to improved durability with modern implants. Reported advantages of the use of MOM THA include very low wear and subsequent osteolysis, increased range of motion to impingement secondary to the availability of larger diameter femoral heads, and the potential to monitor implant performance by serial assessment of metal ion levels. Clinical results of both first-generation and second-generation MOM THA have revealed good survivorship and a low incidence of osteolysis. Although the advantages of low wear and increased range of motion have made MOM THA an attractive bearing surface option, more widespread use of MOM bearing surfaces has been tempered with concern for increased metal ion levels and hypersensitivity reactions.

Cancer after Total Joint Arthroplasty: A Meta-analysis

BACKGROUND

Some epidemiologic and laboratory studies have suggested that total joint arthroplasty could increase the risk of cancer. In this meta-analysis, we attempt to clarify the association of joint arthroplasty with subsequent cancer incidence.

METHODS

We identified population-based studies reporting standardized incidence ratios (SIR) for cancer following large joint arthroplasty. After summing the observed and expected numbers of cases across all qualifying studies, we calculated SIRs for all cancers, and for those at 28 anatomic sites. Latency analysis involving 175,166 patients characterized short-term and long-term cancer associations.

RESULTS

The analyses included 1,435,356 person-years of follow-up and 20,045 cases of cancer. Overall cancer risk among patients with arthroplasty was equal to that for the general population. The relative risk of lung cancer, reduced in the first 5 years after arthroplasty, increased significantly over time to approach that of the general population. Risks for all sites in the luminal gastrointestinal tract were significantly reduced by 10% to 20%; with relative risks that were generally stable over time. Increased risks were seen for cancer of the prostate (SIR, 1.12; 95% confidence interval, 1.08-1.16); similar relative risks were seen in each time period after the procedure. For melanoma, relative risks increased with follow-up to a SIR of 1.43 (95% confidence interval, 1.13-1.79) for 10 or more years after arthroplasty. There was a similar delayed emergence of increased risks for cancers of the urinary tract and oropharynx. The relative risk for bone cancer decreased with time after the procedure.

CONCLUSIONS

There does not seem to be an overall increased risk of cancer following total joint arthroplasty. Although the risks of prostate cancer and melanoma seem to be elevated, there is no obvious mechanism for these associations. Reductions in risk for some malignancies may not be causal.

Malignant tumors at the site of total hip prosthesis. Analytic review of 46 cases

During the years 1974 to 2003, a total of 46 cases of malignant tumors at the site of total hip arthroplasty, 41 sarcomas, 4 lymphomas, and 1 epidermoid carcinoma, have been reported in the Western literature. Soft tissue sarcomas occurred in 31 and bone sarcomas in 10 cases. Malignant fibrous histiocytoma was the most common in 20 (65%) of all soft tissue sarcomas. The patients with malignant tumors had been operated on more often for secondary osteoarthritis and had more local complications than those in ordinary total hip arthroplasty series. Primary osteoarthritis was the indication in 63% and secondary osteoarthritis in 37% of the 38 reported cases. Tumor developed after 8 (17%) revisions. Deep infection complicated 4 (9%) of the cases. Four cases (9%) were preceded by a precondition for cancer, 2 postradiation necroses of the femoral head, 1 chronic sinus, and 1 Mafucci syndrome. Mean age of the patients at the time of first implantation was 59 years (range, 24-79 years). The mean latent period was 6 years (range, 0.5-20 years) from the first operation. Longer latency period did not correlate positively with the cancer risk. Sarcomas were highly aggressive. Of the 31 reported patients, 24 (77%) died within 1 year after the diagnosis. The number of reported sarcoma cases is low considering the total population behind the cases. In addition, one observed local sarcoma from Nordic cohorts was less than expected. Chronic, particle-induced inflammation around the prosthesis does not seem to increase the risk for carcinogenesis.

Cancer incidence and causes of death among total hip replacement patients: A review based on Nordic cohorts with a special emphasis on metal-on-metal bearings

All patients with total hip arthroplasty (THA) are exposed to soluble or particulate forms of Co and Cr. Adverse effects of these wear products are not known. Data from Nordic registries is used to estimate adverse effects on a large scale, based mostly on metal-on-polyethylene bearings. Cancer incidence was in line with the general population when the patients were operated on for all indications and significantly decreased when the indication was primary osteoarthritis. Stomach cancer and colorectal cancers were significantly reduced and prostate cancer and skin melanoma significantly increased. There was no significant excess of cancer in target organs, i.e. liver, kidney, or haematopoietic cancers. THA patients had reduced mortality and extended life expectancy compared with standard Nordic populations.

All-site cancer incidence of the first-generation metal-on-metal McKee-Farrar patients operated on for primary osteoarthritis was in line with the general population after follow-up for up to 28 years. General mortality of these patients was also reduced and they also had an extended life expectancy.

Temporary increases in haematopoietic cancers at different follow-up periods were seen in some cohorts. This malignancy deserves a special record linkage monitoring while large numbers of young patients are provided with the second generation of metal-on-metal prostheses.

Cobalt and chromium ions induce nitration of proteins in human U937 macrophagesin vitro

The in situ localization of nitrotyrosine, a product of the nitration of tyrosine residues by peroxynitrite, in the interface membranes from Co--Cr--Mo and Ti--Al--V prostheses provided evidence of nitric oxide-induced oxidative damage in the periprosthetic environment. In the present study, we compared the effects of different wear products from hip prostheses on the nitration of proteins in macrophages in vitro. Nitration of proteins was measured by Western blot using a polyclonal antibody directed against nitrotyrosines. Results showed that Co(2+) and Cr(3+) ions induced the nitration of a 79 +/- 4 kDa protein in a time- and dose-dependent manner. Indeed, the stimulation was significant (p < 0.05) after 24 h with 10 ppm Co(2+) and reached a plateau level between 48 and 72 h. With Cr(3+), the stimulation was significant (p < 0.05) only after 48 and 72 h. The effect of both Co(2+) and Cr(3+) ions was inhibited by glutathione monoethyl-ester that provides protection against oxidative stress. However, ultrahigh-molecular-weight-polyethylene and alumina ceramic particles had no significant effect on the nitration of proteins. Finally, the results showed that nitrated proteins are mainly found in the cytoplasmic fraction of cells and are absent from the nucleus. In conclusion, our results show that Co(2+) and Cr(3+) ions induce the nitration of cytoplasmic proteins in human U937 macrophages, suggesting that metal ions from MM prostheses have the potential to modify protein function in the periprosthetic environment and in circulating cells.

Effect of cobalt and chromium ions on MMP-1, TIMP-1, and TNF-α gene expression in human U937 macrophages: A role for tyrosine kinases

Previous reports have suggested that the imbalance of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) activity may contribute to prosthetic loosening. However, the mechanisms controlling these enzymes in the periprosthetic environment is unknown. We examined the effect of Co2+ and Cr3+ ions on the expression of genes encoding MMP-1, one of the principal proteinases capable of degrading native fibrillar collagens in the extracellular matrix (ECM), its inhibitor TIMP-1, and TNF-alpha, a cytokine that plays a central role in the induction of implant osteolysis. Human U937 macrophages were incubated in suspension or on phosphorylcholine (PC)-polymer coated surfaces for 24h with Co2+ and Cr3+ ions. The level of mRNAs was determined by reverse transcription-polymerase chain reaction (RT-PCR). Results show that both Co2+ and Cr3+ ions induce the expression of MMP-1, TIMP-1, and TNF-alpha mRNA in a dose-dependent manner in cell suspensions. Tyrosine kinase inhibitors have different effects on these stimulatory effects. Indeed, genistein has only partial inhibitory effect on MMP-1 and TIMP-1, with even less effect on TNF-alpha expression. In contrast, herbimycin A completely blocks MMP-1 and TNF-alpha while partially inhibiting TIMP-1. However, Co2+ and Cr3+ ions had no effect on the expression of MMP-1 and TIMP-1 in macrophages cultured on the PC-polymer, suggesting that the attachment of U937 macrophages to the PC-polymer surfaces may modify their gene expression. In fact, MMP-1 and TIMP-1 seems to be constitutively up-regulated in this condition. However, the effect of Co2+ and Cr3+ ions on macrophages cultured on PC-polymer coated surfaces is similar to what was observed in suspension. Together, these findings indicate that activation of MMP-1, TIMP-1, and TNF-alpha by Co2+ and Cr3+ ions is regulated by tyrosine kinases.

Induction of protein oxidation by cobalt and chromium ions in human U937 macrophages

Metal particles and ions from hip prostheses have the potential to induce the production of reactive oxygen species (ROS), making them prime suspects for disturbing the cellular balance of oxidants/antioxidants (redox state of the cell). To better understand the cellular effect of metal ions from metal-on-metal prostheses, the aim of this study was to examine the effect of cobalt (Co2+) and chromium (Cr3+) ions on protein oxidation in human U937 macrophages. Protein oxidation was measured by Western blot using antibodies directed against dinitrophenylhydrazine (DNP)-derivatized protein carbonyls, the most commonly measured products of protein oxidation in biological samples. Three DNP-derived proteins were detected. The first has a molecular weight of 16 kDa and is expressed at a very low level. The second has a molecular weight of 48 kDa and its level is not regulated by metal ions. The third is a 69 kDa protein and its level is regulated by Co2+ and Cr3+ ions. Therefore, the last band served as a marker of protein oxidation in the present study. Results showed that Co2+ and Cr3+ ions induced a time- and dose-dependent protein oxidation reaching 6.5 and 2.9 times the control after 72 h, respectively, which were inhibited by the antioxidant glutathione monoethyl-ester. Finally, results showed that the oxidized proteins are mainly found in the cytoplasmic fraction of the cells and are absent from the nucleus. In conclusion, our results suggest that metal ions from metal-on-metal prostheses have the potential to modify the redox state of cells both locally (periprosthetic environment) or systematically (circulating cells). The long term effect of these ions on protein oxidation in vivo remains to be investigated.

Cancer following hip and knee arthroplasty: record linkage study

Concerns have been raised that degradation of implants used in hip and knee arthroplasty may lead to an increased risk of some cancers, particularly those of the haematopoietic, lymphatic and urinary systems. We used linked statistical records of hospital admissions and deaths to compare cancer rates in cohorts of people who had undergone hip or knee arthroplasty with a comparison cohort. We did not find an elevated risk for cancer, overall, in either the hip or knee cohort or in both combined (rate ratio for both combined 0.99; 95% confidence intervals 0.95–1.02), or for haematopoietic, lymphatic or urinary system cancers. There was also no elevation in risk of cancer more than 10 years after arthroplasty. Our findings add to the evidence that arthroplasty is safe in respect of cancer risk.

Exploring the Links Between Systemic Lupus Erythematosus and Cancer

For decades, concern has been mounting that individuals with systemic lupus erythematosus (SLE) have increased susceptibility to cancer. Recent data confirm that certain cancers, particularly hematologic, occur more frequently in SLE than in the general population. Numerous pathogenic mechanisms are possible, but hypotheses remain largely speculative. In particular, data are inadequate on how cancer risk in SLE may be related to medication exposures. To evaluate the impact of medication exposures on cancer risk in SLE, cooperative efforts of Systemic Lupus International Collaborating Clinics and Canadian Network for Improved Outcomes in Systemic Lupus are currently in progress. This should provide much-needed insight into the pathogenesis of the association between cancer and SLE.

Serum levels of cobalt and chromium in patients with Sikomet metal-metal total hip replacements

Metal/metal total hip replacements (M/M THRs) made of CoCr-based alloys were reintroduced in hip arthroplasty in order to avoid the problem of polyethylene wear and consequently to diminish the wear debris-related osteolysis. Emerging concerns accompanying the reintroduction of M/M THRs are related to the possibility increase of Co and Cr serum levels and, therefore, a careful surveillance of M/M patients is recommended. In the present work three groups of patients with Sikomet SM21 low-carbon alloy were investigated: retrospective group, prospective group and revision group. The investigation of these different groups of patients provided data concerning the metal concentration as a function of time in situ, as well as time ex situ, i.e., following the removal of M/M bearing. A retrospective group of 25 patients sampled at average 60 +/- 20 months postoperatively showed a 3-fold increase in cobalt and a 4.4-fold increase in chromium compared with the control group. In the prospective group of seven patients both cobalt and chromium increase with time and at average 140 +/- 80 days achieved a significant increase compared with preoperative values. An important contribution of this study to the current knowledge on M/M bearings is achieved by the measurements in the revision group of 10 patients, where we observed a decline of serum Co and Cr levels following the removal of M/M articulation. While the link between the increase in metal serum levels and the presence of M/M THR is proved, the biological impact of these results remains to be elucidated.

An American experience with metal-on-metal total hip arthroplasties: a 7-year follow-up study

This study reviews the clinical performance of 161 hip arthroplasties (154 patients) with the Metasul metal-on-metal articulation and an uncemented modular acetabular component. Between 1995 and 2002 clinical evaluation and radiographic follow-up of patients included Harris hip scores, patient self-assessment, and radiographs. Twelve operative site complications (7.5%) included 6 revision operations, (3.7%) and 3 other complications (1.9%) not needing reoperation. Six revision operations (3.7%) included 1 femoral revision for aseptic loosening (0.06%) and 5 acetabular revisions (3.1%). One cup revision was for recurrent dislocation, 1 for disassociation of the acetabular insert from the cup, 1 for infection, and 2 for unexplained pain. Histologic evidence did not support the diagnosis of metal hypersensitivity in either case of unexplained pain, and 1 had relief following spine surgery. A focal radiolucency, identified as calcar resorption, was observed in 9 patients.

Metal-on-metal total hip arthroplasty: the concerns

The metal-on-metal bearing couple is having a resurgence in clinical applications seen in total hip and hip resurfacing technologies. The most noteworthy advantage of a metal-on-metal implant is the improved wear characteristics seen in vitro on wear simulators and in vivo with retrieved implants. All bearings have disadvantages, and a metal-on-metal bearing is no exception. Concerns exist regarding the generation of metal ions seen in the blood and urine of patients with metal-on-metal implants. These elevated metal ions have theoretical, although not proven, risks related to carcinogenic and biologic concerns. Additionally, concerns exist regarding hypersensitivity, increased incidence of instability and increased costs. Specific patient selection issues arise with metal-on-metal implants. The current generation of implants has only early and mid-term results available, with no long-term series yet published. Therefore, although a metal-on-metal bearing may be considered a viable alternative to either polyethylene or ceramic implants, outstanding and unresolved issues continue to exist with this bearing, as they do with the alternatives.

Can a safe level for metal ions in patients with metal-on-metal total hip arthroplasties be determined?

The single most significant obstacle preventing a broader application of metal-on-metal hip arthroplasties continues to be the concerns regarding elevated metal ion levels in the blood and urine of patients with this bearing. A safe level for metal ions has yet to be defined for patients with metal-on-metal hip arthroplasties. A review of occupational exposure data gives some insight; however, longitudinal studies of large numbers of patients with metal-on-metal implants will ultimately be required to answer specific clinical concerns.

Lessons learned from the hip and knee musculoskeletal outcomes data evaluation and management system

In 1994 the American Academy of Orthopaedic Surgeons established an outcomes initiative. The Musculoskeletal Outcomes Data Evaluation and Management System had two goals: (1) to create validated patient-based functional health questionnaires that would become the gold standard for musculoskeletal research, and (2) to collect data from practicing orthopaedists using these instruments. We assessed the adequacy of the hip and knee portion of the Musculoskeletal Outcomes Data Evaluation and Management System data collection process to learn how to improve these processes. Database elements included demographic and clinical information and health and well-being scales. Only 715 records or 578 patients of the initial 2419 records (30%) had complete baseline and followup information for either hip or knee replacement procedure. Only 17% of the patients who had a knee replacement and 20% of the patients who had a hip replacement returned for followup between 7 and 9 months. The Musculoskeletal Outcomes Data Evaluation and Management System achieved its goal regarding the development of validated questionnaires, but the data collection component did not. The project's implementation and management were flawed. This experience offers the field of orthopaedics valuable lessons that can be applied to future large-scale data collection efforts.

Effect of cobalt and chromium ions on bcl-2, bax, caspase-3, and caspase-8 expression in human U937 macrophages

The bcl-2 and caspase families of proteins play a central role in the modulation of apoptosis. The purpose of this study was to analyze the effect of Co(2+) and Cr(3+) ions on the expression of bcl-2, bax, caspase-3 and caspase-8 to better understand the mechanisms leading to ion-induced apoptosis in macrophages. U937 human macrophages were exposed to Co(2+) and Cr(3+) ions. The expression of proteins was measured by Western blot while caspase activities were measured by colorimetric assay. Results show that Co(2+) ions inhibited bcl-2 expression with significant effect (p<0.05) after 16 h and a maximal 52% inhibitory effect after 24 h. Co(2+) stimulated bax expression with a significant stimulation (p<0.05) after 8 h and a maximal 1.75-fold increase after 16 h. Co(2+) also stimulated the expression of the active fragment of caspase-3 as well as caspase-3 activity maximal increase after 24 h. Co(2+) ions had no effect on caspase-8 expression or activity.Cr(3+) ions inhibited bcl-2 expression with significant effect (p<0.05) after 16 h and a maximal 43% inhibitory effect after 24 h. Cr(3+) stimulated bax expression with significant stimulation (p<0.01) after 8h and a maximal 2.25-fold increase after 24 h. Cr(3+) ions also stimulated the expression of the active fragments of caspase-3 and -8, as well as the activities of both proteases. The effect of Cr(3+) ions on the expression of both caspase active fragments was maximal after 16 h incubation. In conclusion, our results suggest that the modulation of the expression of proteins from the bcl-2 and the caspase families of proteins are implicated in the induction of macrophage apoptosis by Co(2+) and Cr(3+) ions.