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1.  Peptic ulcer disease and Pulmonary disease are Associated with Risk of Periprosthetic Fracture after Primary Total Knee Arthroplasty 
Arthritis care & research  2011;63(10):1471-1476.
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.
doi:10.1002/acr.20548
PMCID: PMC3183369  PMID: 21748860
Total knee arthroplasty; total knee replacement; periprosthetic fracture; predictors; risk factors; comorbidity; Primary TKA
2.  Are Gender, Comorbidity and Obesity Risk factors for Postoperative Periprosthetic Fractures Following Primary Total Hip Replacement? 
The Journal of arthroplasty  2012;28(1):126-131.e2.
We studied the frequency and patient risk factors for postoperative periprosthetic fractures after primary total hip replacement (THR). With a mean follow-up of 6.3 years, 305 postoperative periprosthetic fractures occurred in 14,065 primary THRs. In multivariable-adjusted Cox regression analyses, female gender (Hazard ratio [HR], 1.48;95% confidence interval [CI]:1.17–1.88), Deyo-Charlson comorbidity score of 2 (HR, 1.74 for score of 2;95% CI: 1.25–2.43) or 3 or higher (HR, 1.71;95% CI: 1.26–2.32), ASA class of 2 (HR, 1.84;95% CI: 0.90–3.76), 3 (HR, 2.45;95% CI: 1.18–5.1) or 4 or higher (HR, 2.68;95% CI: 0.70–10.28) were significantly associated with higher risk/hazard and cemented implant with lower hazard (HR, 0.68; 95% CI: 0.54–0.87) of postoperative periprosthetic fractures. Interventions targeted at optimizing comorbidity management may decrease postoperative fractures after THR.
doi:10.1016/j.arth.2012.03.010
PMCID: PMC3414633  PMID: 22552223
3.  Patient factors Predict Periprosthetic Fractures Following Revision Total Hip Replacement 
The Journal of arthroplasty  2012;27(8):1507-1512.
We assessed important patient risk factors for postoperative periprosthetic fractures after revision total hip replacement (THR) using prospectively collected Institutional Joint Registry data. We used univariate and multivariable-adjusted Cox regression analyses. There were 330 postoperative periprosthetic fractures after 6,281 revision THRs. In multivariable-adjusted analyses, hazard [95% confidence interval] of periprosthetic fracture was higher for: women, 1.66 [1.32, 2.08], p<0.001; higher Deyo-Charlson comorbidity index of 2, 1.46 (1.03, 2.07) and index of 3+, 2.01 (1.48, 2.73), overall p<0.001; and operative diagnosis, especially previous non-union, 5.76 (2.55, 13.02), overall p<0.001. Hazard was lower in 61–70 year old, 0.64 (0.49, 0.84) and 71–80 year old 0.57 (0.43, 0.76), compared to <60 years (overall p<0.0001). Our study identified important modifiable and unmodifiable risk factors for fractures after revision THR.
doi:10.1016/j.arth.2011.12.010
PMCID: PMC3360118  PMID: 22342128
4.  Prevalence and risk factors for periprosthetic fracture in older recipients of total hip replacement: a cohort study 
Background
The growing utilization of total joint replacement will increase the frequency of its complications, including periprosthetic fracture. The prevalence and risk factors of periprosthetic fracture require further study, particularly over the course of long-term follow-up. The objective of this study was to estimate the prevalence and risk factors for periprosthetic fractures occurring in recipients of total hip replacement.
Methods
We identified Medicare beneficiaries who had elective primary total hip replacement (THR) for non-fracture diagnoses between July 1995 and June 1996. We followed them using Medicare Part A claims data through 2008. We used ICD-9 codes to identify periprosthetic femoral fractures occurring from 2006–2008. We used the incidence density method to calculate the annual incidence of these fractures and Cox proportional hazards models to identify risk factors for periprosthetic fracture. We also calculated the risk of hospitalization over the subsequent year.
Results
Of 58,521 Medicare beneficiaries who had elective primary THR between July 1995 and June 1996, 32,463 (55%) survived until January 2006. Of these, 215 (0.7%) developed a periprosthetic femoral fracture between 2006 and 2008. The annual incidence of periprosthetic fracture among these individuals was 26 per 10,000 person-years. In the Cox model, a greater risk of periprosthetic fracture was associated with having had a total knee replacement (HR 1.82, 95% CI 1.30, 2.55) or a revision total hip replacement (HR1.40, 95% CI 0.95, 2.07) between the primary THR and 2006. Compared to those without fractures, THR recipients who sustained periprosthetic femoral fracture had three-fold higher risk of hospitalization in the subsequent year (89% vs. 27%, p < 0.0001).
Conclusion
A decade after primary THR, periprosthetic fractures occur annually in 26 per 10,000 persons and are especially frequent in those with prior total knee or revision total hip replacements.
doi:10.1186/1471-2474-15-168
PMCID: PMC4033675  PMID: 24885707
Hip replacement; Periprosthetic fracture; Fracture; Implant; Risk factor; Epidemiology
5.  Metal-on-Metal Total Hip Resurfacing Arthroplasty 
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
PMCID: PMC3379532  PMID: 23074495
6.  Microbiological Culture Findings of the Femoral Heads as a Prognostic Factor in the Total Hip Replacement Surgery 
Clinics in Orthopedic Surgery  2013;5(2):105-109.
Background
In primary total hip replacements (THRs), the dissected femoral heads (FHs) are commonly used to make the bone-chips for the reconstruction in the orthopaedic surgery. The donated FHs are routinely microbiologically cultured to identify and contaminated FHs are discarded. This study examines whether a positive FH culture predicts an infection and prosthetic failure after primary THR.
Methods
The study sampled 274 donated FHs from patients with osteonecrosis (ON), hip joint osteoarthritis (OA), and femoral neck fracture (FNF) in THR to culture the microbes. The FH contamination rates were analyzed for ON, OA, and FNF groups. Proportion of the postoperative infection or prosthetic failure in the group of donors with a positive FH culture were compared to the proportion in the group of donors with a negative FH culture.
Results
The rates of the positive culture in the ON, OA, and FNF groups were 7.1%, 3.8%, and 4.0%, respectively. The infection rate was found to be non-significantly greater in the ON group than in the OA and FNF groups. In the negative culture group, one patient (0.63%) had a postoperative superficial infection, and five patients (3.2%) experienced additional surgeries including a fixation for a periprosthetic fracture, within a minimum follow-up of two years. However, no postoperative infection was encountered, and no revision surgery was required in the positive culture group.
Conclusions
A positive FH culture is not always associated with elevated risks of infection or prosthetic failure after THR. Therefore, such finding cannot be used as a prognostic factor of THR. The FHs that return a positive culture may not lead to the orthopaedic assessment of an infection or other postoperative complication risks in primary THR.
doi:10.4055/cios.2013.5.2.105
PMCID: PMC3664668  PMID: 23730473
Femoral head; Positive culture; Total hip replacement
7.  Periprosthetic infections after total shoulder arthroplasty: a 33-year perspective 
Background
To examine the rates and predictors of deep periprosthetic infections after primary total shoulder arthroplasty (TSA).
Methods
We used prospectively collected data on all primary TSA patients from 1976-2008 at Mayo Clinic Medical Center. We estimated survival free of deep periprosthetic infections after primary TSA using Kaplan-Meier survival. Univariate and multivariable Cox regression was used to assess the association of patient-related factors (age, gender, body mass index), comorbidity (Deyo-Charlson index), American Society of Anesthesiologists class, implant fixation, and underlying diagnosis with risk of infection.
Results
A total of 2,207 patients, with a mean age of 65 years (SD, 12 years), 53% of whom were women, underwent 2,588 primary TSAs. Mean follow-up was 7 years (SD, 6 years), and the mean body mass index was 30 kg/m2 (SD, 6 kg/m2). The American Society of Anesthesiologists class was 1 or 2 in 61% of cases. Thirty-two confirmed deep periprosthetic infections occurred during follow-up. In earlier years, Staphylococcus predominated; in recent years, Propionibacterium acnes was almost as common. The 5-, 10-, and 20-year prosthetic infection–free rates were 99.3% (95% confidence interval [CI], 98.9-99.6), 98.5% (95% CI, 97.8-99.1), and 97.2% (95% CI, 96.0-98.4), respectively. On multivariable analysis, a male patient had a significantly higher risk of deep periprosthetic infection (hazard ratio, 2.67 [95% CI, 1.22-5.87]; P =.01) and older age was associated with lower risk (hazard ratio, 0.97 [95% CI, 0.95-1.00] per year; P =.05).
Conclusions
The periprosthetic infection rate was low at 20-year follow-up. Male gender and younger age were significant risk factors for deep periprosthetic infections after TSA. Future studies should investigate whether differences in bone morphology, medical comorbidity, or other factors are underlying these associations.
doi:10.1016/j.jse.2012.01.006
PMCID: PMC3586318  PMID: 22516570
Total shoulder arthroplasty; periprosthetic infections
8.  Effect of comorbidities and postoperative complications on mortality after hip fracture in elderly people: prospective observational cohort study 
BMJ : British Medical Journal  2005;331(7529):1374.
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.
doi:10.1136/bmj.38643.663843.55
PMCID: PMC1309645  PMID: 16299013
9.  Risk of Complication and Revision Total Hip Arthroplasty Among Medicare Patients with Different Bearing Surfaces 
Background
To address the long-term problems of bearing surface wear and osteolysis associated with conventional metal-polyethylene (M-PE) total hip arthroplasty (THA), metal-metal (M-M), and ceramic-ceramic (C-C) bearings have been introduced. These bearing surfaces are associated with unique risks and benefits and higher costs. However the relative risks of these three bearings in an older population is unknown.
Questions/purposes
We compared the short-term risk of complication and revision THA among Medicare patients having a primary THA with metal-polyethylene (M-PE), metal-metal (M-M), and ceramic-ceramic (C-C) bearings.
Methods
We used the 2005 to 2007 100% Medicare inpatient claim files to perform a matched cohort analysis in three separate cohorts of THA patients (M-PE, M-M, and C-C) who were matched by age, gender, and US census region. Multivariate Cox proportional-hazards models were constructed to compare complication and revision THA risk among cohorts, adjusting for medical comorbidities, race, socioeconomic status, and hospital factors.
Results
After adjusting for patient and hospital factors, M-M bearings were associated with a higher risk of periprosthetic joint infection (hazard ratio, 3.03; confidence interval, 1.02–9.09) when compared with C-C bearings (0.59% versus 0.32%, respectively). There were no other differences among bearing cohorts in the adjusted risk of revision THA or any other complication.
Conclusions
The risk of short-term complication (including dislocation) and revision THA were similar among appropriately matched Medicare THA patients regardless of bearing surface. Hard-on-hard THA bearings are of questionable value in Medicare patients, given the higher cost associated with their use and uncertain long-term benefits in older patients.
Level of Evidence
Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-010-1262-3
PMCID: PMC2914292  PMID: 20165935
10.  Lower limb joint replacement in rheumatoid arthritis 
Introduction
There is limited literature regarding the peri-operative and surgical management of patients with rheumatoid disease undergoing lower limb arthroplasty. This review article summarises factors involved in the peri-operative management of major lower limb arthroplasty surgery for patients with rheumatoid arthritis.
Methods
We performed a search of the medical literature, using the PubMed search engine (http://www.pubmed.gov). We used the following terms: ‘rheumatoid’ ‘replacement’ ‘arthroplasty’ and ‘outcome’.
Findings
The patient should be optimised pre-operatively using a multidisciplinary approach. The continued use of methotrexate does not increase infection risk, and aids recovery. Biologic agents should be stopped pre-operatively due the increased infection rate. Patients should be made aware of the increased risk of infection and periprosthetic fracture rates associated with their disease. The surgical sequence is commonly hip, knee and then ankle. Cemented total hip replacement (THR) and total knee replacement (TKR) have superior survival rates over uncemented components. The evidence is not clear regarding a cruciate sacrificing versus retaining in TKR, but a cruciate sacrificing component limits the risk early instability and potential revision. Patella resurfacing as part of a TKR is associated with improved outcomes. The results of total ankle replacement remain inferior to THR and TKR. RA patients achieve equivalent pain relief, but their rehabilitation is slower and their functional outcome is not as good. However, the key to managing these complicated patients is to work as part of a multidisciplinary team to optimise their outcome.
doi:10.1186/1749-799X-7-27
PMCID: PMC3411461  PMID: 22697352
11.  Periprosthetic Vancouver type B1 and C fractures treated by locking-plate osteosynthesis 
Acta Orthopaedica  2012;83(6):648-652.
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.
doi:10.3109/17453674.2012.747925
PMCID: PMC3555447  PMID: 23140109
12.  Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register 
Acta Orthopaedica  2010;81(1):34-41.
Background and purpose
Since the introduction of total hip arthroplasty (THA) in Sweden, both components have most commonly been cemented. A decade ago the frequency of uncemented fixation started to increase, and this change in practice has continued. We therefore analyzed implant survival of cemented and uncemented THA, and whether the modes of failure differ between the two methods of fixation.
Patients and methods
All patients registered in the Swedish Hip Arthroplasty Register between 1992 and 2007 who received either totally cemented or totally uncemented THA were identified (n = 170,413). Kaplan-Meier survival analysis with revision of any component, and for any reason, as the endpoints was performed. Cox regression models were used to calculate risk ratios (RRs) for revision for various reasons, adjusted for sex, age, and primary diagnosis.
Results
Revision-free 10-year survival of uncemented THA was lower than that of cemented THA (85% vs. 94%, p < 0.001). No age or diagnosis groups benefited from the use of uncemented fixation. Cox regression analysis confirmed that uncemented THA had a higher risk of revision for any reason (RR = 1.5, 95% CI: 1.4–1.6) and for aseptic loosening (RR = 1.5, CI: 1.3–1.6). Uncemented cup components had a higher risk of cup revision due to aseptic loosening (RR = 1.8, CI: 1.6–2.0), whereas uncemented stem components had a lower risk of stem revision due to aseptic loosening (RR = 0.4, CI: 0.3–0.5) when compared to cemented components. Uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 postoperative years than cemented stems (RR = 8, CI: 5–14). The 5 most common uncemented cups had no increased risk of revision for any reason when compared with the 5 most commonly used cemented cups (RR = 0.9, CI: 0.6–1.1). There was no significant difference in the risk of revision due to infection between cemented and uncemented THA.
Interpretation
Survival of uncemented THA is inferior to that of cemented THA, and this appears to be mainly related to poorer performance of uncemented cups. Uncemented stems perform better than cemented stems; however, unrecognized intraoperative femoral fractures may be an important reason for early failure of uncemented stems. The risk of revision of the most common uncemented cup designs is similar to that of cemented cups, indicating that some of the problems with uncemented cup fixation may have been solved.
doi:10.3109/17453671003685400
PMCID: PMC2856202  PMID: 20180715
13.  Mortality After Distal Femur Fractures in Elderly Patients 
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.
doi:10.1007/s11999-010-1530-2
PMCID: PMC3048257  PMID: 20830542
14.  Estimating Risk in Medicare Patients With THA: An Electronic Risk Calculator for Periprosthetic Joint Infection and Mortality 
Background
Although risk factors for periprosthetic joint infection (PJI) and mortality after total hip arthroplasty (THA) have been identified, interactions between specific patient risk factors are poorly understood. Therefore, it is difficult for surgeons to counsel patients on their individual risk of PJI or mortality after THA.
Questions/purposes
We evaluated the interaction between patient clinical and demographic factors on the risk of PJI and mortality after THA and developed an electronic risk calculator for estimating the patient-specific risk of PJI and mortality in Medicare patients with THA.
Methods
We used the Medicare 5% sample claims database to calculate the risk of PJI within 2 years and mortality within 90 days after THA in 53,252 Medicare patients with primary THAs between 1998 and 2009. Logistic regression using 29 comorbid conditions, age, sex, race, and socioeconomic status were used as inputs to develop an electronic risk calculator to estimate patient-specific risk of PJI and mortality after THA.
Results
The overall 2-year risk of PJI and 90-day risk of mortality after primary THA were 2.07% and 1.30%, respectively. White women aged 70 to 74 years with alcohol abuse, depression, electrolyte disorder, peptic ulcer disease, urinary tract infection, rheumatologic disease, preoperative anemia, cardiopulmonary (cardiac arrhythmia, congestive heart failure, ischemic heart disease, chronic pulmonary disease) comorbidities, and peripheral vascular disease were at highest risk for PJI. White women aged 65 to 69 years with electrolyte disorder, hemiplegia/paraplegia, hypertension, hypothyroidism, metastatic tumor, preoperative anemia, coagulopathy, cardiopulmonary (congestive heart failure, chronic pulmonary disease) and psychiatric (psychoses, depression) comorbidities, malignancies, and peripheral vascular disease were at highest risk for mortality. An electronic risk calculator was developed to estimate the risk of PJI and mortality in Medicare patients with THA.
Conclusions
This electronic risk calculator can be used to counsel Medicare patients regarding their patient-specific risks of PJI and mortality after THA.
Level of Evidence
Level II, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.
doi:10.1007/s11999-012-2605-z
PMCID: PMC3549162  PMID: 23179112
15.  Obesity is a Major Risk Factor for Prosthetic Infection after Primary Hip Arthroplasty 
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.
doi:10.1007/s11999-007-0016-3
PMCID: PMC2505299  PMID: 18196388
16.  A population-based survival analysis describing the association of body mass index on time to revision for total hip and knee replacements: results from the UK general practice research database 
BMJ Open  2013;3(11):e003614.
Objectives
Against a backdrop of rising levels of obesity, we describe and estimate associations of body mass index (BMI), age and gender with time to revision for participants undergoing primary total hip (THR) or knee (TKR) replacement in the UK.
Design
Population-based cohort study.
Setting
Routinely collected primary care data from a representative sample of general practices, including linked data on all secondary care events.
Participants
Population-based cohort study of 63 162 patients with THR and 54 276 with TKR in the UK General Practice Research Database between 1988 and 2011.
Primary and secondary outcomes
Risk of THR and TKR revision associated with BMI, age and gender, after adjusting for the competing risk of death.
Results
The 5-year cumulative incidence rate for THR was 2.2% for men and 1.8% for women (TKR 2.3% for men, 1.6% for women). The adjusted overall subhazard ratio (SHR) for patients with THR undergoing subsequent hip revision surgery, with a competing risk of death, were estimated at 1.020 (95% CI 1.009 to 1.032) per additional unit (kg/m2) of BMI, 1.23 (95% CI 1.10 to 1.38) for men compared with women and 0.970 (95% CI 0.967 to 0.973) per additional year of age. For patients with TKR, the equivalent estimates were 1.015 (95% CI 1.002 to 1.028) for BMI; 1.51 (95% CI 1.32 to 1.73) for gender and 0.957 (95% CI 0.951 to 0.962) for age. Morbidly obese patients with THR had a 65.5% increase (95% CI 15.4% to 137.3%, p=0.006) in the subhazard of revision versus the normal BMI group (18.5–25). The effect for TKR was smaller (a 43.9% increase) and weaker (95% CI 2.6% to 103.9%, p=0.040).
Conclusions
BMI is estimated to have a small but statistically significant association with the risk of hip and knee revision, but absolute numbers are small. Further studies are needed in order to distinguish between effects for specific revision surgery indications.
doi:10.1136/bmjopen-2013-003614
PMCID: PMC3845068  PMID: 24285628
17.  Risk factors for revision of primary total hip replacement: Results from a national case-control study 
Arthritis care & research  2012;64(12):1879-1885.
Objective
To study risk factors for revision of primary total hip replacement (THR) in a US population-based sample.
Methods
Using Medicare claims, we identified beneficiaries from 29 US states who underwent primary THR between 7/1/1995 and 6/30/1996, and followed them through 12/31/2008. Potential cases had ICD-9 codes indicating revision THR. Each case was matched by state with one control THR recipient who was alive and unrevised when the case had revision THR. We abstracted hospital records to document potential risk factors. We examined associations between preoperative factors and revision risk using multivariate conditional logistic regression.
Results
The analysis data set consisted of 719/836 case-control pairs with complete data for analysis variables. Factors associated with higher revision odds in multivariate models were age ≤75 at primary surgery (OR 1.52, 95% CI 1.20, 1.92), height in highest tertile (OR 1.40, 95% CI 1.06, 1.85), weight in highest tertile (OR 1.66, 95% CI 1.24, 2.22), cemented femoral component (OR 1.44, 95% CI 1.10, 1.87), prior contralateral primary THR (OR 1.36, 95% CI 1.05, 1.76), other prior orthopedic surgery (OR 1.45, 95% CI 1.13, 1.84), and living with others (versus alone; OR 1.26, 95% CI 0.99, 1.61).
Conclusion
This first US population-based case-control study of risk factors for revision of primary THR showed that younger, taller, and heavier patients and those receiving a cemented femoral component had greater likelihood of revision THR over twelve-year follow-up. Effects of age and body size on revision risk should be addressed by clinicians with patients considering primary THR.
doi:10.1002/acr.21760
PMCID: PMC3510659  PMID: 23193090
18.  Treatment Results of a Periprosthetic Femoral Fracture Case Series: Treatment Method for Vancouver Type B2 Fractures Can Be Customized 
Clinics in Orthopedic Surgery  2014;6(2):138-145.
Background
Currently, an algorithmic approach for deciding treatment options according to the Vancouver classification is widely used for treatment of periprosthetic femoral fractures after hip arthroplasty. However, this treatment algorithm based on the Vancouver classification lacks consideration of patient physiology and surgeon's experience (judgment), which are also important for deciding treatment options. The purpose of this study was to assess the treatment results and discuss the treatment options using a case series.
Methods
Eighteen consecutive cases with periprosthetic femoral fractures after total hip arthroplasty and hemiarthroplasty were retrospectively reviewed. A locking compression plate system was used for osteosynthesis during the study period. The fracture type was determined by the Vancouver classification. The treatment algorithm based on the Vancouver classification was generally applied, but was modified in some cases according to the surgeon's judgment. The reasons for modification of the treatment algorithm were investigated. Mobility status, ambulatory status, and social status were assessed before the fracture and at the latest follow-up. Radiological results including bony union and stem stability were also evaluated.
Results
Thirteen cases were treated by osteosynthesis, two by revision arthroplasty and three by conservative treatment. Four cases of type B2 fractures with a loose stem, in which revision arthroplasty is recommended according to the Vancouver classification, were treated by other options. Of these, three were treated by osteosynthesis and one was treated conservatively. The reasons why the three cases were treated by osteosynthesis were technical difficulty associated with performance of revision arthroplasty owing to severe central migration of an Austin-Moore implant in one case and subsequent severe hip contracture and low activity in two cases. The reasons for the conservative treatment in the remaining case were low activity, low-grade pain, previous wiring around the fracture and light weight. All patients obtained primary bony union and almost fully regained their prior activities.
Conclusions
We suggest reaching a decision regarding treatment methods of periprosthetic femoral fractures by following the algorithmic approach of the Vancouver classification in addition to the assessment of each patient's hip joint pathology, physical status and activity, especially for type B2 fractures. The customized treatments demonstrated favorable overall results.
doi:10.4055/cios.2014.6.2.138
PMCID: PMC4040372  PMID: 24900893
Femur; Periprosthetic fracture; Hip arthroplasty; Vancouver classification
19.  Increased risk of revision in patients with non-traumatic femoral head necrosis 
Acta Orthopaedica  2014;85(1):11-17.
Background and purpose
Previous studies of patients who have undergone total hip arthroplasty (THA) due to femoral head necrosis (FHN) have shown an increased risk of revision compared to cases with primary osteoarthritis (POA), but recent studies have suggested that this procedure is not associated with poor outcome. We compared the risk of revision after operation with THA due to FHN or POA in the Nordic Arthroplasty Register Association (NARA) database including Denmark, Finland, Norway, and Sweden.
Patients and methods
427,806 THAs performed between 1995 and 2011 were included. The relative risk of revision for any reason, for aseptic loosening, dislocation, deep infection, and periprosthetic fracture was studied before and after adjustment for covariates using Cox regression models.
Results
416,217 hips with POA (mean age 69 (SD 10), 59% females) and 11,589 with FHN (mean age 65 (SD 16), 58% females) were registered. The mean follow-up was 6.3 (SD 4.3) years. After 2 years of observation, 1.7% in the POA group and 3.0% in the FHN group had been revised. The corresponding proportions after 16 years of observation were 4.2% and 6.1%, respectively. The 16-year survival in the 2 groups was 86% (95% CI: 86–86) and 77% (CI: 74–80). After adjusting for covariates, the relative risk (RR) of revision for any reason was higher in patients with FHN for both periods studied (up to 2 years: RR = 1.44, 95% CI: 1.34–1.54; p < 0.001; and 2–16 years: RR = 1.25, 1.14–1.38; p < 0.001).
Interpretation
Patients with FHN had an overall increased risk of revision. This increased risk persisted over the entire period of observation and covered more or less all of the 4 most common reasons for revision.
doi:10.3109/17453674.2013.874927
PMCID: PMC3940986  PMID: 24359026
20.  The Impact of Comorbidity on Perioperative Outcomes of Hip Fractures in a Geriatric Fracture Model 
Background:
Older adults who sustain hip fractures usually have multiple coexisting medical problems that may impact their treatment and outcomes. The geriatric fracture center (GFC) provides a model of care that standardizes treatment and optimizes outcomes. The purpose of this study is to determine whether GFC patients with a higher burden of comorbidity or specific comorbidities are at risk for worsened perioperative outcomes, such as increased time to surgery (TTS), postoperative complications, and longer length of hospital stay (LOS).
Method:
A total of 1077 patients aged 60 years and older who underwent surgery for a proximal femur fracture between April 15, 2005, and September 30, 2010, were evaluated. Comorbidities measured in the Charlson Comorbidity index were abstracted through chart review. Outcomes were TTS, postoperative complications, and LOS.
Results:
Most patients were white, with an average age of 85. One half lived in either a nursing home or an assisted living facility. The mean Charlson score was 3.06 and the nursing home residents had a significantly higher score compared to community dwellers (3.4 vs 2.8; P < .0001). Dementia was the most common comorbidity. There was no difference in the LOS or TTS based on Charlson score. The overall complication rate was 44% with delirium being the most common postoperative complication. Peripheral vascular disease, history of solid tumor, and peptic ulcer disease predicted delirium incidence. Charlson score predicted complication risk, with an odds ratio of 1.12 for each point increase.
Conclusion:
Frailty and comorbidity put this hip fracture population at high risk for adverse perioperative outcomes. This study shows that in the GFC model of care the comorbidity burden did not impact the TTS and LOS but did predict postoperative complication rate.
doi:10.1177/2151458512463392
PMCID: PMC3598442  PMID: 23569706
hip fractures; dementia; comorbidity; model of care; perioperative outcomes
21.  Predictive value of Medicare claims data for identifying revision of index hip replacement was modest 
Journal of clinical epidemiology  2010;64(5):10.1016/j.jclinepi.2010.05.005.
Objective
To determine the positive predictive value of Medicare claims for identifying revision of total hip replacement (THR), a frequent marker of THR quality and outcome.
Study Design and Setting
We obtained Medicare Part A (Hospital) claims from seven states on patients that had primary THR from July 1995 through June 1996. We searched claims to determine whether these THR recipients had a subsequent revision THR through December 2006. We selected a sample of subjects with codes indicating both index primary and subsequent revision THR. We obtained medical records for both procedures to establish whether the revision occurred on the same side as index primary THR.
Results
Three hundred seventy-four subjects had codes indicating primary THR in 1995–96 and subsequent revision. Seventy-one percent (95% confidence interval: 66, 76) of the revisions were performed on the index joint and would be correctly attributed as revisions of the index THR, using Medicare Claims data.
Conclusion
Claims data on revision THR that do not contain information on the side that was operated on are ambiguous with respect to whether the revision was performed on the index or contralateral side. Claims-based analyses of revisions after an index THR should acknowledge and adjust for this source of potential misclassification.
doi:10.1016/j.jclinepi.2010.05.005
PMCID: PMC3886276  PMID: 20800448
Total hip replacement; Revision; Administrative data; Medicare claims; Misclassification; Accuracy
22.  Relation between surgeon volume and risk of complications after total hip arthroplasty: propensity score matched cohort study 
Objectives To identify a cut point in annual surgeon volume associated with increased risk of complications after primary elective total hip arthroplasty and to quantify any risk identified.
Design Propensity score matched cohort study.
Setting Ontario, Canada
Participants 37 881 people who received their first primary total hip arthroplasty during 2002-09 and were followed for at least two years after their surgery.
Main outcome measure The rates of various surgical complications within 90 days (venous thromboembolism, death) and within two years (infection, dislocation, periprosthetic fracture, revision) of surgery.
Results Multivariate splines were developed to visualize the relation between surgeon volume and the risk for various complications. A threshold of 35 cases a year was identified, under which there was an increased risk of dislocation and revision. 6716 patients whose total hip arthroplasty was carried out by surgeons who had done ≤35 such procedure in the previous year were successfully matched to patients whose surgeon had carried out more than 35 procedures. Patients in the former group had higher rates of dislocation (1.9% v 1.3%, P=0.006; NNH 172) and revision (1.5% v 1.0%, P=0.03; NNH 204).
Conclusions In a cohort of first time recipients of total hip arthroplasty, patients whose operation was carried by surgeons who had performed 35 or fewer such procedures in the year before the index procedure were at increased risk for dislocation and early revision. Surgeons should consider performing 35 cases or more a year to minimize the risk for complications. Furthermore, the methods used to visualize the relationship between surgeon volume and the occurrence of complications can be easily applied in any jurisdiction, to help inform and optimize local healthcare delivery.
doi:10.1136/bmj.g3284
PMCID: PMC4032026  PMID: 24859902
23.  Outcomes following surgical treatment of periprosthetic femur fractures: a single centre series 
Canadian Journal of Surgery  2014;57(3):209-213.
Background
Periprosthetic femoral fracture after total hip arthroplasty (THA) is an increasing clinical problem and a challenging complication to treat surgically. The aim of this retrospective study was to review the treatment of periprosthetic fractures and the complication rate associated with treatment at our institution.
Methods
We reviewed the cases of patients with periprosthetic femoral fractures treated between January 2004 and June 2009. We used the Vancouver classification to assess fracture types, and we identified the surgical interventions used for these fracture types and the associated complications.
Results
We treated 45 patients with periprosthetic femoral fractures during the study period (15 men, 30 women, mean age 78 yr). Based on Vancouver classification, 2 patients had AL fractures, 9 had AG, 15 had B1, 24 had B2, 2 had B3 and 4 had C fractures. Overall, 82% of fractures united with a mean time to union of 15 (range 2–64) months. Fourteen patients (31%) had complications; 11 of them had a reoperation: 6 to treat an infection, 6 for nonunion and 2 for aseptic femoral component loosening.
Conclusion
Periprosthetic fractures are difficult to manage. Careful preoperative planning and appropriate intraoperative management in the hands of experienced surgeons may increase the chances of successful treatment. However, patients should be counselled on the high risk of complications when presenting with this problem.
doi:10.1503/cjs.014813
PMCID: PMC4035404  PMID: 24869614
24.  Perioperative Hyperglycemia and Postoperative Infection after Lower Limb Arthroplasty 
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.
PMCID: PMC3125936  PMID: 21527113
blood glucose; diabetes mellitus; hip and knee arthroplasty; infection; orthopedic surgery
25.  Hip Fracture Incidence in Relation to Age, Menopausal Status, and Age at Menopause: Prospective Analysis 
PLoS Medicine  2009;6(11):e1000181.
Using data from the UK Million Women Study, Emily Banks and colleagues investigate the relationships between the incidence of hip fracture and a woman's age, menopausal status, and age at menopause.
Background
Bone mineral density is known to decrease rapidly after the menopause. There is limited evidence about the separate contributions of a woman's age, menopausal status and age at menopause to the incidence of hip fracture.
Methods and Findings
Over one million middle-aged women joined the UK Million Women Study in 1996–2001 providing information on their menopausal status, age at menopause, and other factors, which was updated, where possible, 3 y later. All women were registered with the UK National Health Service (NHS) and were routinely linked to information on cause-specific admissions to NHS hospitals. 561,609 women who had never used hormone replacement therapy and who provided complete information on menopausal variables (at baseline 25% were pre/perimenopausal and 75% postmenopausal) were followed up for a total of 3.4 million woman-years (an average 6.2 y per woman). During follow-up 1,676 (0.3%) were admitted to hospital with a first incident hip fracture. Among women aged 50–54 y the relative risk (RR) of hip fracture risk was significantly higher in postmenopausal than premenopausal women (adjusted RR 2.22, 95% confidence interval [CI] 1.22–4.04; p = 0.009); there were too few premenopausal women aged 55 y and over for valid comparisons. Among postmenopausal women, hip fracture incidence increased steeply with age (p<0.001), with rates being about seven times higher at age 70–74 y than at 50–54 y (incidence rates of 0.82 versus 0.11 per 100 women over 5 y). Among postmenopausal women of a given age there was no significant difference in hip fracture incidence between women whose menopause was due to bilateral oophorectomy compared to a natural menopause (adjusted RR 1.20, 95% CI 0.94–1.55; p = 0.15), and age at menopause had little, if any, effect on hip fracture incidence.
Conclusions
At around the time of the menopause, hip fracture incidence is about twice as high in postmenopausal than in premenopausal women, but this effect is short lived. Among postmenopausal women, age is by far the main determinant of hip fracture incidence and, for women of a given age, their age at menopause has, at most, a weak additional effect.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Anyone can break a hip but most hip fractures occur in elderly people. As people age, their bones gradually lose minerals and become less dense, which weakens the bones and makes them more susceptible to fracture. Because women lose bone density faster than men as they age and because women constitute the majority of the elderly, three-quarters of hip fractures occur in women. Hip fractures can cause long-term health problems and premature death. Thus, although surgical repair of a broken hip usually only requires a hospital stay of about a week, a quarter of elderly people who were living independently before their fracture have to stay in a nursing home for at least a year after their injury and a fifth of elderly people who break a hip die within the year. Most hip fractures are caused by falls. Regular exercise to improve strength and balance combined with review of medicines (to reduce side effects and interactions), regular eye examinations, and the removal of fall hazards from the home can help to prevent hip fractures in elderly people.
Why Was This Study Done?
Bone density decreases very rapidly in women immediately after menopause—the time when menstruation permanently stops—and then continues to decrease more slowly with age. Most women have their menopause in their early 50s but menopause can occur in younger women. Early menopause is thought to be a risk factor for osteoporosis (thinning of the bones) and fractures later in life but little is known about how menopause influences hip fracture risk as women age. In this prospective study (a type of study in which a group of people is followed for several years to see whether they develop a particular condition), the researchers investigate the incidence of hip fractures in relation to age, menopausal status, and age at menopause among the participants of the Million Women Study. This study, which recruited 1.3 million women aged 50–64 years who attended UK breast cancer screening clinics between 1996 and 2001, has been investigating how reproductive and lifestyle factors affect women's health.
What Did the Researchers Do and Find?
At enrollment and three years later, the study participants provided information about their menopausal status and other health and lifestyle factors likely to affect their fracture risk. From these data, the researchers identified more than half a million women who had never used hormone replacement therapy (which reduces fracture risk) and who had given complete information about their menopausal status. They then looked for statistical associations between the occurrence of a first hip fracture in these women over the next few years and their age, menopausal status, and age at menopause. Among women aged 50–54 years, postmenopausal women were twice as likely to have a hip fracture as premenopausal women. Among postmenopausal women, the incidence of hip fractures increased steeply with age and was seven times higher in 70–74-year olds than in 50–54-year olds. Women who had their menopause before age 45 had a slightly increased risk of hip fracture but any effect of age at menopause on the risk of hip fracture was small compared to the effect of age itself, and the slightly increased risk may have been due to other factors that could not be fully accounted for in the analysis.
What Do These Findings Mean?
These findings indicate that around the time of menopause, although hip fractures are rare, the risk of a fracture in postmenopausal women is twice that in premenopausal women. The findings also show that among postmenopausal women, age is the major determinant of hip fracture risk and that for women of a given age, their age at menopause has little effect on hip fracture risk. Women attending breast cancer screening clinics and completing questionnaires about their health may not be representative of the general population. Furthermore, these findings rely on women self-reporting their menopausal status accurately. Nevertheless, the results of this study suggest that clinicians advising women about hip fracture prevention should probably base their advice on the woman's age and on age-related factors such as frailty rather than on factors related to menopause. Clinicians can also now reassure elderly women who had an early menopause that their risk of hip fracture is unlikely to be higher than that of similar women who had a later menopause.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000181.
The American Academy of Orthopaedic Surgeons has detailed information about hip fractures
The US National Institute of Arthritis and Muscoloskeletal and Skin Diseases has an interactive feature called “Check up on your bones and provides detailed information about osteoporosis, including advice on fall prevention
The US Centers for Disease Control and Prevention has a fact sheet about hip fractures among older adults
MedlinePlus has links to resources about hip fracture, osteoporosis, and menopause (in English and Spanish)
More information on the Million Women Study is available
doi:10.1371/journal.pmed.1000181
PMCID: PMC2766835  PMID: 19901981

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