Related Articles

Objective

To assess the association of specific comorbidities with periprosthetic fractures after primary total knee replacement (TKA)

Methods

We used the prospectively collected data in the Mayo Clinic Total Joint Registry from 1989-2008 on all patients who had undergone primary TKA. The outcome of interest was postoperative periprosthetic fractures during the follow-up. Main predictors of interest were comorbidities grouped from the validated Deyo-Charlson index. Multivariable-adjusted Cox regression analyses adjusted for gender, age, body mass index (BMI), American Society of Anesthesiology (ASA) class, operative diagnosis and implant fixation. Hazard ratios and 95% confidence intervals were calculated.

Results

We included 17,633 primary TKAs with a mean follow-up of 6.3 years. The mean age was 68 years, 55% were women and mean BMI was 31. There were 188 postoperative periprosthetic fractures on postoperative day one or later; 162 fractures (86%) occurred postoperative day 90 day or later. In multivariable analyses that simultaneously adjusted for all comorbidities and other variables (age, gender, BMI, ASA, operative diagnosis, cement status), two conditions were significantly associated with increased hazard of postoperative periprosthetic fractures: peptic ulcer disease, hazard ratio of 1.87 (95% confidence interval:1.28, 2.75; p=0.0014); and chronic obstructive pulmonary disease (COPD) hazard ratio of 1.62 (95% confidence interval:1.10, 2.40; p=0.02).

Conclusions

Peptic ulcer disease and COPD are associated with higher risk of periprosthetic fractures after primary TKA. This may be related to the disease or their treatments, which needs further study. Identification of specific risk factor may allow for implementation of intervention strategies to reduce this risk.

Background and purpose

Historically, the treatment of periprosthetic femoral fractures (PFFs) has been associated with a high frequency of complications and reoperations. The preferred treatment is internal fixation, a revision of the femoral stem, or a combination of both. An improved understanding of plate use during internal fixation, and the introduction of locking-plate osteosynthesis may lead to improved outcome. We evaluated the outcome of Vancouver type B1 and C PFFs treated by locking-plate osteosynthesis, by assessing rates of fracture union and reoperations and by analyzing failure cases.

Patients and methods

From 2002 through 2011, 58 consecutive patients (60 fractures) with low-energy PFF around or below a stable femoral stem, i.e. Vancouver type B1 and C fractures, underwent osteosynthesis with a locking plate. All patients had a total hip replacement (THR). They were followed up clinically and radiographically, with 6 weeks between visits, until fracture union or until death. Fracture union was evaluated 6 months postoperatively.

Results

At a median follow-up time of 23 (0–121) months after PFF, 8 patients (8 fractures) had been reoperated due either to infection (n = 4), failure of fixation (n = 3), or loosening of the femoral stem (n = 1). All the patients who had been followed up for at least 6 months—and who did not undergo reoperation or die—went on to fracture union (n = 43).

Interpretation

Locking-plate osteosynthesis of periprosthetic Vancouver type B1 and C fractures gives good results regarding fracture union. It appears that spanning of the prosthesis to avoid stress-rising areas is important for successful treatment. Infection is the major cause of failure.

Early periprosthetic osteolysis following total hip replacement (THR) as a result of septic etiology has been well understood. Periprosthetic bone loss as a result of metastatic infiltration is an uncommon and infrequent cause of early, progressive loosening of joint replacement prosthesis. Proximal femur has been the most common site of involvement compared to acetabular prosthesis. The rarity of this clinical entity can lead to delay in definitive diagnosis and management, thus affecting the final outcome. Breast is the commonest site of carcinoma in female patients despite which not many cases of periprosthetic metastasis have been reported in the literature. We present the first case of extensive, isolated periacetabular bone destruction following a THR in a 59 years old female patient with a history of breast carcinoma. Patients with known primary malignancy should be screened thoroughly before operation and should be followed regularly after joint replacement surgery to detect any metastatic foci around the prosthesis.

Keywords

Periprosthetic metastasis; Total hip replacement; Breast carcinoma

Background and purpose

Primary and dynamically maintained periprosthetic bone formation is essential for osseointegration of hip implants to host bone. Bone morphogenetic proteins (BMPs) play a role in osteoinductive bone formation. We hypothesized that there is an increased local synthesis of BMPs in the synovial membrane-like interface around aseptically loosened total hip replacement (THR) implants, as body attempts to generate or maintain implant fixation.

Patients and methods

We compared synovial membrane-like interface tissue from revised total hip replacements (rTHR, n = 9) to osteoarthritic control synovial membrane samples (OA, n = 11. Avidin-biotin-peroxidase complex staining and grading of BMP-2, BMP-4, BMP-6, and BMP-7 was done. Immunofluorescence staining was used to study BMP proteins produced by mesenchymal stromal/stem cells (MSCs) and osteoblasts.

Results and interpretation

All BMPs studied were present in the synovial lining or lining-like layer, fibroblast-like stromal cells, interstitial macrophage-like cells, and endothelial cells. In OA and rTHR samples, BMP-6 positivity in cells, inducible by the proinflammatory cytokines tumor necrosis factor−α and interleukin-1β, predominated over expression of other BMPs. Macrophage-like cells positive for BMP-4, inducible in macrophages by stimulation with particles, were more frequent around loosened implants than in control OA samples, but apparently not enough to prevent loosening. MSCs contained BMP-2, BMP-4, BMP-6, and BMP-7, but this staining diminished during osteogenesis, suggesting that BMPs are produced by progenitor cells in particular, probably for storage in the bone matrix.

We evaluated the mid-term clinical and radiographical performance of a cohort of patients who underwent primary total hip replacement with a modern, forged cobalt–chrome, polished cemented femoral stem with proximal and distal centralisation. Sixty-seven patients with 73 hybrid total hip replacements were followed up clinically and radiographically for an average of 6.1 years (4–8.5). No patient was lost. No hips required revision, and all stems are radiographically well-fixed. Four hips developed localised osteolysis: one at the site of a proximal periprosthetic fracture, another at the level of a lateral femoral window of a previous core decompression, the third at the mid third of the femoral component, and the fourth on the greater trochanter, associated with accelerated polyethylene wear. This modern polished stem yielded excellent, predictable clinical and radiographic results at an intermediate follow-up.

Background

Hip fractures in the elderly are associated with high 1-year mortality rates, but whether patients with other lower extremity fractures are exposed to a similar mortality risk is not clear.

Questions/purposes

We evaluated the mortality of elderly patients after distal femur fractures; determined predictors for mortality; analyzed the effect of surgical delay; and compared survivorship of elderly patients with distal femur fractures with subjects in a matched hip fracture group.

Patients and Methods

We included 92 consecutive patients older than 60 years with low-energy supracondylar femur fractures treated between 1999 and 2009. Patient, fracture, and treatment characteristics were extracted from operative records, charts, and radiographs. Data regarding mortality were obtained from the Social Security Death Index.

Results

Age-adjusted Charlson Comorbidity Index and a previous TKA were independent predictors for decreased survival. Congestive heart failure, dementia, renal disease, and history of malignant tumor led to shorter survival times. Patients who underwent surgery more than 4 days versus 48 hours after admission had greater 6-month and 1-year mortality risks. No differences in mortality were found comparing patients with native distal femur fractures with patients in a hip fracture control group.

Conclusions

Periprosthetic fractures and fractures in patients with dementia, heart failure, advanced renal disease, and metastasis lead to reduced survival. The age-adjusted Charlson Comorbidity Index may serve as a useful tool to predict survival after distal femur fractures. Surgical delay greater than 4 days increases the 6-month and 1-year mortality risks. Mortality after native fractures of the distal femur in the geriatric population is high and similar to mortality after hip fractures.

Level of Evidence

Level II, prognostic study. See the guidelines online for a complete description of evidence.

Background

Examine 90-day postoperative mortality and its predictors following shoulder arthroplasty

Methods

We identified vital status of all adults who underwent primary shoulder arthroplasty (Total shoulder arthroplasty (TSA) or humeral head replacement (HHR)) at the Mayo Clinic from 1976-2008, using the prospectively collected information from Total Joint Registry. We used univariate logistic regression models to assess the association of gender, age, body mass index, American Society of Anesthesiologist (ASA) class, Deyo-Charlson comorbidity index, an underlying diagnosis and implant fixation with odds of 90-day mortality after TSA or HHR. Multivariable models additionally adjusted for the type of surgery (TSA versus HHR). Adjusted Odds ratio (OR) with 95% confidence interval (CI) were calculated.

Results

Twenty-eight of the 3, 480 patient operated died within 90-days of shoulder arthroplasty (0.8%). In multivariable-adjusted analyses, the following factors were associated with significantly higher odds of 90-day mortality: higher Deyo-Charlson index (OR, 1.54; 95% CI:1.39, 1.70; p < 0.001); a diagnosis of tumor (OR, 16.2; 95%CI:7.1, 36.7); and ASA class III (OR, 3.57; 95% CI:1.29, 9.91; p = 0.01) or class IV (OR, 13.4; 95% CI:2.44, 73.86; p = 0.003). BMI ≥ 30 was associated with lower risk of 90-day mortality (OR, 0.25; 95% CI:0.08, 0.78). In univariate analyses, patients undergoing TSA had significantly lower 90-day mortality of 0.4% (8/2, 580) compared to 1% in HHR (20/1, 411) (odds ratio, 0.22 (95% CI: 0.10, 0.50); p = 0.0003).

Conclusions

90-day mortality following shoulder arthroplasty was low. An underlying diagnosis of tumor, higher comorbidity and higher ASA class were risk factors for higher 90-day mortality, while higher BMI was protective. Pre-operative comorbidity management may impact 90-day mortality following shoulder arthroplasty. A higher unadjusted mortality in patients undergoing TSA versus HHR may indicate the underlying differences in patients undergoing these procedures.

Background

One of the most serious complications after major orthopedic surgery is deep wound or periprosthetic joint infection. Various risk factors for infection after hip and knee replacement surgery have been reported, including patients' comorbidities and surgical technique factors. We investigated whether hyperglycemia and diabetes mellitus (DM) are associated with infection that requires surgical intervention after total hip and knee arthroplasty.

Methods

We reviewed our computerized database for elective primary total hip and knee arthroplasty from 2000 to 2008. Demographic information, past medical history of patients, perioperative biochemistry, and postoperative complications were reviewed.

Patients were divided into two groups: infected group (101 patients who had surgical intervention for infection at our institution within 2 years after primary surgery) and noninfected group (1847 patients with no intervention with a minimum of one year follow-up. The data were analyzed using t, chi-squared, and Fisher's exact tests.

Results

There were significantly more diabetes patients in the infected group compared with the noninfected group (22% versus 9%, p < .001). Infected patients had significantly higher perioperative blood glucose (BG) values: preoperative BG (112 ± 36 versus 105 ± 31 mg/dl, p = .043) and postoperative day (POD) 1 BG (154 ± 37 versus 138 ± 31 mg/dl, p < .001). Postoperative morning hyperglycemia (BG >200 mg/dl) increased the risk for the infection more than two-fold. Non-DM patients were three times more likely to develop the infection if their morning BG was >140 mg/dl on POD 1, p = .001. Male gender, higher body mass index, knee arthroplasty, longer operative time and hospital stay, higher comorbidity index, history of myocardial infarction, congestive heart failure, and renal insufficiency were also associated with the infection.

Conclusions

Diabetes mellitus and morning postoperative hyperglycemia were predictors for postoperative infection following total joint arthroplasty. Even patients without a diagnosis of DM who developed postoperative hyperglycemia had a significantly increased risk for the infection.

The interest in minimally invasive approaches for total hip replacement (THR) has not waned in any way. We carried out a prospective and comparative study in order to analyse the interest of the anterolateral minimal invasive (ALMI) approach in comparison with a minimally invasive posterior (MIP) approach. A group of 35 primary THRs with a large head using the ALMI approach was compared with a group of 43 THR performed through a MIP approach. The groups were not significantly different with respect to age, sex, bony mass index, ASA score, Charnley class, diagnoses and preoperative Womac index and PMA score. The preoperative Harris Hip Score was significantly lower in the ALMI group. The duration of surgical procedure was longer and the calculated blood loss more substantial in the ALMI group. The perioperative complications were significantly more frequent in this group, with four greater trochanter fractures, three false routes, one calcar fracture, and two metal back bascules versus one femoral fracture in MIP group. Other postoperative data (implant positioning, morphine consumption, length of hospital stay, type of discharge) are comparable, such as the early functional results. No other complication has been noted during the first 6 months. The ALMI approach uses the intermuscular interval between the tensor fascia lata and the gluteus medius. It leaves intact the abductor muscles, the posterior capsule and the short external rotators. The early clinical results are excellent, despite the initial complications related to the initial learning curve for this approach and the use of a large head. The stability and the absence of muscular damage should permit acceleration of the postoperative rehabilitation in parallel with less perioperative complications after the initial learning curve.

Objectives To evaluate postoperative medical complications and the association between these complications and mortality at 30 days and one year after surgery for hip fracture and to examine the association between preoperative comorbidity and the risk of postoperative complications and mortality.

Design Prospective observational cohort study.

Setting University teaching hospital.

Participants 2448 consecutive patients admitted with an acute hip fracture over a four year period. We excluded 358 patients: all those aged < 60; those with periprosthetic fractures, pathological fractures, and fractures treated without surgery; and patients who died before surgery.

Interventions Routine care for hip fractures.

Main outcome measures Postoperative complications and mortality at 30 days and one year.

Results Mortality was 9.6% at 30 days and 33% at one year. The most common postoperative complications were chest infection (9%) and heart failure (5%). In patients who developed postoperative heart failure mortality was 65% at 30 days (hazard ratio 16.1, 95% confidence interval 12.2 to 21.3). Of these patients, 92% were dead by one year (11.3, 9.1 to 14.0). In patients who developed a postoperative chest infection mortality at 30 days was 43% (8.5, 6.6 to 11.1). Significant preoperative variables for increased mortality at 30 days included the presence of three or more comorbidities (2.5, 1.6 to 3.9), respiratory disease (1.8, 1.3 to 2.5), and malignancy (1.5, 1.01 to 2.3).

Conclusions In elderly people with hip fracture, the presence of three or more comorbidities is the strongest preoperative risk factor. Chest infection and heart failure are the most common postoperative complications and lead to increased mortality. These groups offer a clear target for specialist medical assessment.

The purpose of this study was to explore the increasing prevalence of factors affecting hospital charges for primary total hip replacement/total knee replacement (THR/TKR). This study analysed 37,918 THR and 76,727 TKR procedures performed in Taiwan from 1996 to 2004. Odds ratio (OR) and effect size (ES) were calculated to assess the relative change rate. Multiple regression models were employed to predict hospital charges. The following factors were associated with increased hospital charges: age younger than 65 years old; increased disease severity (Charlson comorbidity index [CCI] = 1 or ≥2); absence of primary diagnoses of osteoarthritis (OA), rheumatoid arthritis (RA), avascular necrosis (AVN); treatment at a hospital or by a surgeon performing a high volume of operations; and longer average length of stay (ALOS). The Bureau of National Health Insurance (BNHI) should ensure that surgeons take precautionary measures to minimise complications and maximise quality of life after surgery. Use of joint prostheses from different manufacturers can reduce costs without compromising patient satisfaction.

Background

Study pain and use of pain medications and their predictors after primary Total Hip Arthroplasty (THA).

Methods

We examined whether gender, age (reference, < = 60 yrs), body mass index (BMI; reference, <25 kg/m2)), comorbidity measured by Deyo-Charlson index (5-point increase), anxiety and depression predict moderate-severe hip pain and use of pain medications 2- and 5-years after primary THA. Multivariable logistic regression adjusted for these predictors and distance from medical center, operative diagnosis, American Society of Anesthesiologists (ASA) score and implant type.

Results

Moderate-severe pain was reported by 8.1% at 2-years and 10.8% at 5-years. Significant predictors of moderate-severe pain at 2-year follow-up were [Odds ratio (95% confidence interval)]: BMI 35-39.9, 1.8 (1.2,2.8); BMI > = 40, 1.7 (1.0,2.9); depression, 2.1 (1.4,3.0). Moderate-severe pain at 5-years was more common in patients with higher BMI: 25-29.9, 1.5 (1.1,2.1); 30-34.9, 1.8 (1.2,2.6); 35-39.9, 1.9 (1.2,3.1); and > = 40, 3.1 (1.7,5.7).

Significant predictors of NSAID use were [Odds ratio (95% confidence interval)]: female gender at 2- and 5-years, 1.4 (1.1,1.7) and 1.4 (1.1,1.8); BMI 35-39.9 at 2-years, 1.9 (1.4, 2.6) and 30-34.9 at 2-years, 1.7 (1.2,2.4); and depression at 5-years, 1.8 (1.2,2.8).

Significant predictors of opioid medication use were [Odds ratio (95% confidence interval)]: female gender at 2- and 5-years, 2.0 (1.1,3.0) and 2.4 (1.4,4.0); BMI 30-34.9 at 2-years, 2.0 (1.0,3.9); and depression at 2-years, 2.0 (1.1,3.7).

Conclusions

Higher BMI and depression impacted moderate-severe pain; and female gender, higher BMI and depression predicted use of pain medications at 2- and 5-years post-primary THA.

Executive Summary

Objective

The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population.

Clinical Need

Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years.

Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries.

The Technology

Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup.

Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR.

A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada.

Review Strategy

A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety).

The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained.

Summary of Findings

 

Health Outcomes

The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score.

The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative Oxford hip scores, but no preoperative values were reported.

None of the reviewed studies reported procedure-related deaths. Four studies reported implant survival rates ranging from 94.4% to 99.7% for a follow-up period of 2.8 to 3.5 years. Three studies reported on the range of motion. One reported improvement in all motions including flexion, extension, abduction-adduction, and rotation, and another reported improvement in flexion. Yet another reported improvement in range of motion for flexion abduction-adduction and rotation arc. However, the author reported a decrease in the range of motion in the arc of flexion in patients with Brooker class III or IV heterotopic bone (all patients were men).

Safety of Metal-on-Metal Hip Resurfacing Arthroplasty

There is a concern about metal wear debris and its systemic distribution throughout the body. Detectable metal concentrations in the serum and urine of patients with metal hip implants have been described as early as the 1970s, and this issue is still controversial after 35 years.

Several studies have reported high concentration of cobalt and chromium in serum and/or urine of the patients with metal hip implants. Potential toxicological effects of the elevated metal ions have heightened concerns about safety of MOM bearings. This is of particular concern in young and active patients in whom life expectancy after implantation is long.

Since 1997, 15 studies, including 1 randomized clinical trial, have reported high levels of metal ions after THR with metal implants. Some of these studies have reported higher metal levels in patients with loose implants.

Adverse Biological Effects of Cobalt and Chromium

Because patients who receive a MOM hip arthroplasty are shown to be exposed to high concentrations of metallic ions, the Medical Advisory Secretariat searched the literature for reports of adverse biological effects of cobalt and chromium. Cobalt and chromium make up the major part of the metal articulations; therefore, they are a focus of concern.

Risk of Cancer

To date, only one study has examined the incidence of cancer after MOM and polyethylene on metal total hip arthroplasties. The results were compared to that of general population in Finland. The mean duration of follow-up for MOM arthroplasty was 15.7 years; for polyethylene arthroplasty, it was 12.5 years. The standardized incidence ratio for all cancers in the MOM group was 0.95 (95% CI, 0.79–1.13). In the polyethylene on metal group it was 0.76 (95% CI, 0.68–0.86). The combined standardized incidence ratio for lymphoma and leukemia in the patients who had MOM THR was 1.59 (95% CI, 0.82–2.77). It was 0.59 (95% CI, 0.29–1.05) for the patients who had polyethylene on metal THR. Patients with MOM THR had a significantly higher risk of leukemia. All patients who had leukemia were aged over than 60 years.

Cobalt Cardiotoxicity

 

Epidemiological Studies of Myocardiopathy of Beer Drinkers

An unusual type of myocardiopathy, characterized by pericardial effusion, elevated hemoglobin concentrations, and congestive heart failure, occurred as an epidemic affecting 48 habitual beer drinkers in Quebec City between 1965 and 1966. This epidemic was directly related the consumption of a popular beer containing cobalt sulfate. The epidemic appeared 1 month after cobalt sulfate was added to the specific brewery, and no further cases were seen a month after this specific chemical was no longer used in making this beer. A beer of the same name is made in Montreal, and the only difference at that time was that the Quebec brand of beer contained about 10 times more cobalt sulphate. Cobalt has been added to some Canadian beers since 1965 to improve the stability of the foam but it has been added in larger breweries only to draught beer. However, in small breweries, such as those in Quebec City, separate batches were not brewed for bottle and draught beer; therefore, cobalt was added to all of the beer processed in this brewery.

In March 1966, a committee was appointed under the chairmanship of the Deputy Minister of Health for Quebec that included members of the department of forensic medicine of Quebec’s Ministry of Justice, epidemiologists, members of Food and Drug Directorate of Ottawa, toxicologists, biomedical researchers, pathologists, and members of provincial police. Epidemiological studies were carried out by the Provincial Ministry of Health and the Quebec City Health Department.

The association between the development of myocardiopathy and the consumption of the particular brand of beer was proven. The mortality rate of this epidemic was 46.1% and those who survived were desperately ill, and recovered only after a struggle for their lives.

Similar cases were seen in Omaha (Nebraska). The epidemic started after a cobalt additive was used in 1 of the beers marketed in Nebraska. Sixty-four patients with the clinical diagnosis of alcoholic myocardiopathy were seen during an 18-month period (1964–1965). Thirty of these patients died. The first patient became ill within 1 month after cobalt was added to the beer, and the last patient was seen within 1 month of withdrawal of cobalt.

A similar epidemic occurred in Minneapolis, Minnesota. Between 1964 and 1967, 42 patients with acute heart failure were admitted to a hospital in Minneapolis, Minnesota. Twenty of these patients were drinking 6 to 30 bottles per day of a particular brand of beer exclusively. The other 14 patients also drank the same brand of beer, but not exclusively. The mortality rate from the acute illness was 18%, but late deaths accounted for a total mortality rate of 43%. Examination of the tissue from these patients revealed markedly abnormal changes in myofibrils (heart muscles), mitochondria, and sarcoplasmic reticulum.

In Belgium, a similar epidemic was reported in 1966, in which, cobalt was used in some Belgian beers. There was a difference in mortality between the Canadian or American epidemic and this series. Only 1 of 24 patients died, 1.5 years after the diagnosis. In March 1965, at an international meeting in Brussels, a new heart disease in chronic beer drinkers was described. This disease consists of massive pericardial effusion, low cardiac output, raised venous pressure, and polycythemia in some cases. This syndrome was thought to be different from the 2 other forms of alcoholic heart disease (beriberi and a form characterized by myocardial fibrosis).

The mystery of the above epidemics as stated by investigators is that the amount of cobalt added to the beer was below the therapeutic doses used for anemia. For example, 24 pints of Quebec brand of beer in Quebec would contain 8 mg of cobalt chloride, whereas an intake of 50 to 100 mg of cobalt as an antianemic agent has been well tolerated. Thus, greater cobalt intake alone does not explain the occurrence of myocardiopathy. It seems that there are individual differences in cobalt toxicity. Other features, like subclinical alcoholic heart disease, deficient diet, and electrolyte imbalance could have been precipitating factors that made these patients susceptible to cobalt’s toxic effects.

In the Omaha epidemic, 60% of the patients had weight loss, anorexia, and occasional vomiting and diarrhea 2 to 6 months before the onset of cardiac symptoms. In the Quebec epidemic, patients lost their appetite 3 to 6 months before the diagnosis of myocardiopathy and developed nausea in the weeks before hospital admission. In the Belgium epidemic, anorexia was one of the most predominant symptoms at the time of diagnosis, and the quality and quantity of food intake was poor. Alcohol has been shown to increase the uptake of intracoronary injected cobalt by 47%. When cobalt enters the cells, calcium exits; this shifts the cobalt to calcium ratio. The increased uptake of cobalt in alcoholic patients may explain the high incidence of cardiomyopathies in beer drinkers’ epidemics.

As all of the above suggest, it may be that prior chronic exposure to alcohol and/or a nutritionally deficient diet may have a marked synergistic effect with the cardiotoxicity of cobalt.

Conclusions

MOM hip resurfacing arthroplasty has been shown to be an effective arthroplasty procedure as tested in younger patients.

However, evidence for effectiveness is based only on 7 case series with short duration of follow-up (2.8–3.5 years). There are no RCTs or other well-controlled studies that compare MOM hip resurfacing with THR.

Revision rates reported in the MOM studies using implants currently licensed in Canada (hybrid systems, uncemented acetabular, and cemented femoral) range from 0.3% to 3.6% for a mean follow-up ranging from 2.8 to 3.5 years.

Fracture of femoral neck is not very common; it occurs in 0.4% to 2.2% of cases (as observed in a short follow-up period).

All the studies that measured health outcomes have reported improvement in Harris Hip and SF-12 scores; 1 study reported significant reduction in pain and improvement in function, and 2 studies reported significant improvement in SF-12 scores. One study reported significant improvement in UCLA Hip scores.

Concerns remain on the potential adverse effects of metal ions. Longer-term follow-up data will help to resolve the inconsistency of findings on adverse effects, including toxicity and carcinogenicity.

Ontario-Based Economic Analysis

The device cost for MOM ranges from $4,300 to $6,000 (Cdn). Traditional hip replacement devices cost about $2,000 (Cdn). Using Ontario Case Costing Initiative data, the total estimated costs for hip resurfacing surgery including physician fees, device fees, follow-up consultation, and postsurgery rehabilitation is about $15,000 (Cdn).

Cost of Total Hip Replacement Surgery in Ontario

MOM hip arthroplasty is generally recommended for patients aged under 55 years because its bone-conserving advantage enables patients to “buy time” and hence helps THRs to last over the lifetime of the patient. In 2004/2005, 15.9% of patients who received THRs were aged 55 years and younger. It is estimated that there are from 600 to 1,000 annual MOM hip arthroplasty surgeries in Canada with an estimated 100 to 150 surgeries in Ontario. Given the increased public awareness of this device, it is forecasted that demand for MOM hip arthroplasty will steadily increase with a conservative estimate of demand rising to 1,400 cases by 2010 (Figure 10). The net budget impact over a 5-year period could be $500,000 to $4.7 million, mainly because of the increasing cost of the device.

Projected Number of Metal-on-Metal Hip Arthroplasty Surgeries in Ontario: to 2010

Background

Metallic wires and cables are commonly used in primary and revision THA for fixation of periprosthetic fractures and osteotomies of the greater trochanter. These systems provide secure fixation and high healing rates but fraying, third-body generation, accelerated wear of the bearing surface, and injury to the surgical team remain concerning.

Questions/purposes

We determined the rate of cable failure, union, and complications associated with a novel, nonmetallic cerclage cable in periprosthetic fracture and osteotomy fixation during THA.

Methods

We retrospectively reviewed 29 patients who had primary and revision THAs using nonmetallic cables. Indications for use included fixation of an extended trochanteric osteotomy, intraoperative fracture of the proximal femur, strut allograft fixation, and a Vancouver B1 periprosthetic fracture of the femur. All patients were evaluated clinically and radiographically immediately postoperatively, at 3 weeks, 6 weeks, 3 months, and then annually thereafter. The minimum followup was 13 months (mean, 21 months; range, 13–30 months).

Results

Two of the 29 patients (7%) developed a nonunion; all remaining osteotomies, fractures and allografts had healed at the time of most recent evaluation. Four patients (14%) dislocated postoperatively; two were treated successfully with closed reduction, while the other two required reoperation. We identified no evidence of breakage or other complications directly attributable to the cables.

Conclusions

The nonmetallic periprosthetic cables used in this series provided adequate fixation to allow for both osteotomy and fracture healing. We did not observe any complications directly related to the cables.

Level of Evidence Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

This study was based on data from the Finnish Arthroplasty Register. From 1990 to 1999, 33,154 primary hip arthroplasties were performed in Finland. Only periprosthetic fractures treated by a revision arthroplasty were registered. The six most used femoral components were compared using survival analysis and Cox's regression model. The incidence of periprosthetic fractures was calculated separately for the years 1990–1994 and 1995–1999. The incidence in the first period was greater than in the latter. Survival analysis and Cox's regression model showed that gender, prosthesis type and age were of no significance as risk factors for periprosthetic fractures.

Background

Salmonella species can be rarely isolated from periprosthetic joint infections, however when present, are usually part of a severe septic clinical picture.

Case presentations

Two patients presented with late infected hip replacements to our institution. The first patient with multiple comorbidities had a confirmed Salmonella Enteridis infection with an abscess in the groin, with loosening of both components. He underwent a successful one stage cemented revision hip replacement, followed by 6 weeks of antibiotic therapy (ciprofloxacin). He had no recurrence or complications. The second patient was admitted in a septic condition with ARDS to the Intensive Care Unit 7 years following an uncemented total hip replacement. From an ultrasound guided hip aspirate Salmonella cholerae-suis was isolated. He underwent a successful a two-stage revision hip replacement.

Conclusions

Successful treatment of such potentially life threatening infections is achievable using modern orthopaedic techniques and close collaboration with the infectious diseases specialists.

Surgery is indicated for symptomatic knee osteoarthritis (OA) when conservative measures are unsuccessful. High tibial osteotomy (HTO), unicompartmental knee arthroplasty (UKA), and total knee arthroplasty (TKA) are surgical options intended to relieve knee OA pain and dysfunction. The choice of surgical intervention is dependent on several factors such as disease location, patient age, comorbidities, and activity levels. Regardless of surgical treatment, complications such as infection, loosening or lysis, periprosthetic fracture, and postoperative pain are known risks and are indications for revision surgery. The clinical and economic implications for revision surgery are underappreciated. Over 55,000 revision surgeries were performed in 2010 in the US, with 48% of these revisions in patients under 65 years. Total costs associated with each revision TKA surgery have been estimated to be in excess of $49,000. The current annual economic burden of revision knee OA surgery is $2.7 billion for hospital charges alone. By 2030, assuming a 5-fold increase in the number of revision procedures, this economic burden will exceed $13 billion annually. It is appealing to envision a therapy that could delay or obviate the need for arthroplasty. From an actuarial standpoint, this would have the theoretical downstream effect of substantially reducing the number of revision procedures. Although no known therapies currently meet these criteria, such a breakthrough would have a tremendous impact in lessening the clinical and economic burden of knee OA revision surgery.

The medical records and radiographs of 99 patients treated for a periprosthetic femur fracture after total hip arthroplasty over a 17-year period at a single institution were prospectively reviewed. Fractures were classified according to the Vancouver system and stratified as to treatment method. Sixty-six patients had complete records available and a minimum of 12 months follow-up. Overall, 86% of the patients achieved fracture union. The success rate of cemented revision in the B2 and B3 groups was 84%, whereas cement-less revision was 86% successful. The complication rate of surgical treatment was 29%. Fracture union with a stable implant was possible in the majority of cases. Our results support the use of the Vancouver classification as a treatment algorithm.

Background

Iceland's geographical isolation with a stable and small population gives a rare opportunity for follow-up studies of medical interventions. Total hip replacements (THR) have been done at FSA Central Hospital in Akureyri, Iceland since 1982 with the Exeter hip implant being in use from the beginning.

Methods

Hospital records for all patients operated on with THR between 1982 and the end of 1999 were reviewed and the patients were followed until the end of 2001. Information was gathered regarding the indication for primary surgery, the reason for revision if needed, as well as that of any complications. Survival statistics were used to calculate the cumulative revision rate.

Results

The mean age at primary THR was 68.4 years for males and 68.8 years for females. 654 primary THRs were done; of which 571 (87 %) were due to osteoarthritis. 37 of the primary arthroplasties had been revised before the end of year 2001.

Conclusion

We have in this unique 2–20 year study of 654 THRs with no loss to follow-up for the patients, found revision rates that conform with the large Swedish THR registry. Complication rates in general are in agreement with that reported for other comparable patient groups, while infection rates appear lower.

Twenty-five patients with periprosthetic femoral fractures were admitted to the Ulster Hospital between August 1998 and May 2000. Average age was 77 years (range, 42-96 years) with a female to male ratio of 2:1. Twenty-four of the fractures occurred following primary joint arthroplasty on average 7.6 years from insertion of the primary prosthesis. One patient sustained an intraoperative fracture during revision surgery. In the majority (80%), the periprosthetic femoral fracture was associated with a traumatic event. On average, two days elapsed from the time of injury until admission to our unit. Time from admission to surgery was on average 4 days. All patients were treated by open fracture fixation. Duration of stay in the fracture unit was on average 20 days. Prior to their fracture 92% of patients were living at home and 84% were mobile either unaided or with the use of a stick. At most recent review, 72% are back living at home and 60% are mobile either unaided or with the use of a stick. We emphasise that there is the likelihood of an increase in periprosthetic femoral fractures due to the increasing number of primary arthroplasties being performed on a more active, ageing population. Preventative measures and cost implications are also discussed.

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Study design

Comparative study.

Objective

To compare periprosthetic tissue reactions observed after total disc replacement (TDR), total hip arthroplasty (THA) and total knee arthroplasty (TKA) revision surgery.

Summary of background data

Prosthetic wear debris leading to particle disease, followed by osteolysis, is often observed after THA and TKA. Although the presence of polyethylene (PE) particles and periprosthetic inflammation after TDR has been proven recently, osteolysis is rarely observed. The clinical relevance of PE wear debris in the spine remains poorly understood.

Methods

Number, size and shape of PE particles, as well as quantity and type of inflammatory cells in periprosthetic tissue retrieved during Charité TDR (n=22), THA (n=10) and TKA (n=4) revision surgery were compared. Tissue samples were stained with hematoxylin/eosin and examined by using light microscopy with bright field and polarized light.

Results

After THA, large numbers of PE particles <6 µm were observed, which were mainly phagocytosed by macrophages. The TKA group had a broad size range with many larger PE particles and more giant cells. In TDR, the size range was similar to that observed in TKA. However, the smallest particles were the most prevalent with 75% of the particles being <6 µm, as seen in revision THA. In TDR, both macrophages and giant cells were present with a higher number of macrophages.

Conclusions

Both small and large PE particles are present after TDR revision surgery compatible with both THA and TKA wear patterns. The similarities between periprosthetic tissue reactions in the different groups may give more insight in the clinical relevance of PE particles and inflammatory cells in the lumbar spine. The current findings may help to improve TDR design as applied from technologies previously developed in THA and TKA with the goal of a longer survival of TDR.

The incidence of obesity and the number of hip arthroplasties being performed in Australia each year are increasing. Although uncommon, periprosthetic infection after surgery can have a devastating effect on patient outcomes. We therefore asked whether obesity correlated with periprosthetic infection after primary hip arthroplasty. We further asked whether variables such as patient comorbidities, operative time, blood transfusions, use of drains, and cementation practices correlated with periprosthetic infection. We hypothesized obesity was an independent risk factor for the development of acute periprosthetic infection after primary hip arthroplasty. We reviewed 1207 consecutive primary hip arthroplasties separating patients into four weight groups, normal, overweight, obese, and morbidly obese, and compared for incidence of periprosthetic infection between the groups. We observed a considerably higher infection rate in obese patients; the correlation was independent of patient comorbidities such as diabetes and cardiovascular disease. We also observed a correlation between infection rates and using a posterior approach in obese patients. The incidence of periprosthetic infection was not influenced by operative time, transfusion requirements, use of drains, and cementation practices. In this series, obesity was an independent risk factor for acute periprosthetic infection after primary hip arthroplasty.

Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Severe distal femoral bone loss and instability in revision TKA is challenging. We retrospectively reviewed 39 rotating-hinged distal femoral replacement devices in 37 patients to examine whether improved results were obtainable, using one design, over previously published results. The average age of the patients was 76 years (standard deviation, 10 years). Indications for distal femoral replacement included 11 revision TKAs, 13 periprosthetic fractures, 11 reimplantations, two complex primary TKAs, one distal femoral nonunion, and one acute distal femur fracture. Minimum followup was 24 months (mean, 46 months; range, 24–109 months). Eight patients died during followup. There were five reoperations: two patients with recurrent infection after two-stage treatment, one patient with a periprosthetic fracture treated by open reduction and internal fixation, one patient with late hematogenous infection, and one patient with bearing exchange to treat hyperextension. No failures from aseptic loosening were seen. Knee Society scores improved from 39 preoperatively to 87, and pain scores improved from 18 preoperatively to 43. Distal femoral prosthetic replacement with a tumor-type implant in severe cases provides excellent pain relief and function with a low short-term reoperation rate and an implant survivorship rate of 87% at 46 months.

Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Background

Matrix metalloproteinase (MMP)1, interleukin(IL)6 and vitamin D receptor (VDR) have been implicated in the biological cascade of events initiated by particulate wear debris and bacterial infection, resulting in periprosthetic bone loss around loosened total hip replacements (THRs). The individual responses to such stimuli may be dictated by genetic variation.

Objective

To study the effect of single‐nucleotide polymorphisms (SNPs) within these candidate genes.

Methods

A case–control study of the MMP1, IL6 and VDR genes was performed for possible association with deep sepsis or aseptic loosening. All cases included in the study were Caucasian patients with osteoarthritis who had received a cemented Charnley total hip arthroplasty (THA) and polyethylene acetabular cup. Cases consisted of 91 patients with early aseptic loosening and 71 patients with microbiological evidence of deep infection on surgery. Controls consisted of 150 patients with THAs that were clinically asymptomatic for over 10 years and showed no radiographic features of aseptic loosening. DNA samples from all individuals were genotyped using Taqman allelic discrimination.

Results

The C allele (p = 0.001; OR = 3.27; 95% CI 2.21 to 4.83) and C/C genotype (p = 0.001) for the MMP1 SNP were highly associated with aseptic failure when compared with controls. No statistically significant relationships were found between aseptic loosening and the MMP2, MMP4, IL6 –174 or VDRL SNPs. The T allele (p = 0.007; OR = 1.76; 95% CI 1.16 to 2.66) and T/T genotype (p = 0.028) for VDR‐T were statistically associated with osteolysis owing to deep infection as compared with controls. No statistically significant relationship was found between septic failure and any of the other SNPs examined in this study.

Conclusions

Aseptic loosening and possibly deep infection of THR may be due to the genetic influence of candidate susceptibility genes. SNP markers may serve as predictors of implant survival and aid in pharmacogenomic prevention of THR failure.

To examine whether patient characteristics predict patient-reported pain and function 2- or 5-years after revision total hip arthroplasty (THA). In a prospective cohort of revision THA patients, we examined whether gender, age, body mass index (BMI), comorbidity (Deyo–Charlson index) and depression predicted moderate–severe hip pain, moderate–severe activity limitation (≥3 activities), dependence on walking aids and use of pain medications, using multivariable regression analysis. Significant predictors of moderate–severe pain at 2- and 5-years were [odds ratio (95% confidence interval)]: female gender, 1.3 (1.0, 1.6) and 1.5 (1.1, 1.9) and age 61–70, 0.7 (0.5, 1.0) and 0.7 (0.5, 1.0; reference (ref),≤60 years). BMI, 30–34.9, 1.4 (1.0, 1.9; ref BMI≤25) and depression, 1.6 (1.0, 2.5) were significantly associated with higher odds of moderate–severe pain at 2 years, but not at 5 years. Significant predictors of nonsteroidal anti-inflammatory drugs (NSAIDs) use 2-years post-revision THA were female gender, 1.4 (1.1, 1.7), BMI, 30–34.9, 1.4 (1.0, 2.0) and age, 71–80, 0.7 (0.5, 0.9). At 5 years, female gender, 1.6 (1.2, 2.2) was significantly associated with NSAID use. Significant predictors of narcotic use 2-years post-revision THA were older age, 61–70, 0.5 (0.3, 0.7) and 71–80, 0.4 (0.3, 0.7) and depression, 2.4 (1.2, 4.6). At 5 years, women, had significantly higher odds 1.8 (1.1, 2.9) of narcotic use and those in age group 61–70 years, significantly lower odds of narcotic use, 0.4 (0.2, 0.7). Similarly, female gender, older age (>70) and BMI of 30 or higher were each significantly associated with higher odds of moderate–severe activity limitation at both, 2- and 5-years. Depression was associated with higher risk at 2 years, 1.7 (1.1, 2.6) and higher Deyo–Charlson score with a higher risk of moderate–severe activity limitation at 5 years, 1.7 (1.1, 2.7). Obesity and depression, considered modifiable clinical factors, were important independent predictors of pain, functional limitation and use of pain medications, following revision THA.