Hormone replacement therapy and mid-term implant survival following knee or hip arthroplasty for osteoarthritis: a population-based cohort study

The causal impact of bioavailable testosterone levels on osteoarthritis: a bidirectional Mendelian randomized study

BACKGROUND

It has been shown that low testosterone levels are associated with the development of osteoarthritis (OA). In our study, we aimed to investigate a bidirectional causal relationship between bioavailable testosterone levels and OA using Mendelian randomization (MR) analysis.

METHODS

In our study, the datasets from publicly available genome-wide association study (GWAS) were adopted, including the OA-related dataset (ukb-b-14486) and the bioavailable testosterone levels-related dataset (ebi-a-GCST90012104). The UKB-B-14,486 dataset contains 462,933 samples in total, including 38,472 OA samples, 424,461 control samples, and 9,851,867 SNPs, all collected from the European population in 2018. Additionally, the EBI-A-GCST90012104 dataset includes 382,988 samples and 16,137,327 SNPs, which reflect data from the European population in 2020. In total, five methods were utilized, namely MR Egger, Weighted median, Inverse variance weighted (IVW), Simple mode, and Weighted mode. Among them, IVW was the main analytical method. Additionally, the sensitivity analysis was carried out through the heterogeneity test, the horizontal pleiotropy test, and the Leave-One-Out (LOO) method.

RESULTS

The result of forward MR analysis demonstrated that bioavailable testosterone levels were considerably relevant to OA, and were a risk factor for OA (OR = 1.01, 95% CI: [1.00, 1.02], P = 0.02). However, through reverse MR analysis, we did not find a causal relationship between OA and bioavailable testosterone levels. Moreover, the results of the sensitivity analysis suggested that our results were reliable.

CONCLUSION

The results of our study supported a causal relationship between bioavailable testosterone levels and OA.

The effects of pre-operative anti-osteoporotic use on total joint arthroplasty complications: A national database study

Background

The current study aims to analyze the effect of pre-operative non-bisphosphonate anti-osteoporotic drugs on complication and revision rates following total joint arthroplasty (TJA).

Methods

A retrospective cohort analysis of the PearlDiver (PearlDiver Technologies, Colorado Springs, CO) database was performed. The database was queried to identify all patients who underwent total hip arthroplasty (THA) or total knee arthroplasty (TKA) with history of hip or knee osteoarthritis and either osteopenia or osteoporosis. The treatment groups consisted of patients prescribed non-bisphosphonate and bisphosphonate osteomodulatory agents for 1 year prior to and following surgery. The treatment groups were matched to control cohorts by age, gender, and comorbidities. Chi-square analyses were used to compare outcomes between paired cohorts.

Results

There were no statistically significant differences (p ≤ 0.05) in risk of aseptic loosening, broken prosthesis, dislocation of prosthetic joint, periprosthetic fracture, periprosthetic osteolysis, postoperative infection, full or partial revision, or stress fracture between both the non-bisphosphonate and bisphosphonate groups following THA or TKA. Comparisons between both groups and control cohort also yielded no significant differences.

Conclusion

The current study detected no significant differences in early post-operative complications following TJA between patients treated with different classes of anti-osteoporotic medications versus untreated osteopenic/osteoporotic patients. Further research is required to fully understand the impact of osteomodulatory medications on TJA outcomes. Analysis should continue to ensure a high-quality standard of care and aim to better understand outcomes for such patients requiring TJA.

Hormone Replacement Therapy in Postmenopausal Women Undergoing Total Hip Arthroplasty is Associated With Reduced 10-Year Periprosthetic Femoral Fracture Rate

BACKGROUND

In postmenopausal women who are estrogen deficient, hormone replacement therapy (HRT) has been shown to improve fragility fracture risk. However, few studies have examined the relationship between HRT and periprosthetic fracture (PPF) risk after total hip arthroplasty (THA). The purpose of this study was to determine the impact of HRT use on 10-year PPF risk following THA.

METHODS

A retrospective cohort study was conducted using a large national database. Women who underwent elective THA were identified and stratified based on preoperative (< 6 months) HRT use. Those taking HRT were propensity score matched at a 1:2 ratio to those who do not have a history of HRT use based on age and Charlson Comorbidity Index score. Kaplan-Meier and Cox proportional hazards analyses were conducted to determine rates of PPF, revision, and aseptic loosening within 10 years of surgery. Regression analyses were performed to determine 90-day rates of venous thromboembolism (VTE) after controlling for perioperative VTE prophylaxis. In total, 21,220 patients were included.

RESULTS

Patients who were taking HRT before THA demonstrated a lower risk of PPF (hazard ratio: 0.8; 95% confidence interval: 0.6 to 0.9) within 10 years of THA, but a similar risk of all-cause revision surgery and revision for aseptic loosening. The HRT cohort demonstrated lower odds of deep vein thrombosis (odds ratio: 0.7; 95% confidence interval: 0.6 to 1.0) and similar rates of pulmonary embolism.

CONCLUSIONS

In postmenopausal women, HRT use before elective THA was associated with lower rates of PPF within 10 years of surgery and was not associated with increased VTE risk. Given these results, appropriate HRT usage in patients may have a role in reducing PPF after THA.

Causal association of menstrual reproductive factors on the risk of osteoarthritis: A univariate and multivariate Mendelian randomization study

OBJECTIVE

Several observational studies have revealed a potential relationship between menstrual reproductive factors (MRF) and osteoarthritis (OA). However, the precise causal relationship remains elusive. This study performed Mendelian randomization (MR) to provide deeper insights into this relationship.

METHODS

Utilizing summary statistics of genome-wide association studies (GWAS), we conducted univariate MR to estimate 2 menstrual factors (Age at menarche, AAM; Age at menopause, AMP) and 5 reproductive factors (Age at first live birth, AFB; Age at last live birth, ALB; Number of live births, NLB; Age first had sexual intercourse, AFSI; Age started oral contraceptive pill, ASOC) on OA (overall OA, OOA; knee OA, KOA and hip OA, HOA). The sample size of MRF ranged from 123846 to 406457, and the OA sample size range from 393873 to 484598. Inverse variance weighted (IVW) method was used as the primary MR analysis methods, and MR Egger, weighted median was performed as supplements. Sensitivity analysis was employed to test for heterogeneity and horizontal pleiotropy. Finally, multivariable MR was utilized to adjust for the influence of BMI on OA.

RESULTS

After conducting multiple tests (P<0.0023) and adjusting for BMI, MR analysis indicated that a lower AFB will increase the risk of OOA (odds ratio [OR] = 0.97, 95% confidence interval [CI]: 0.95-0.99, P = 3.39×10-4) and KOA (OR = 0.60, 95% CI: 0.47-0.78, P = 1.07×10-4). ALB (OR = 0.61, 95% CI: 0.45-0.84, P = 2.06×10-3) and Age AFSI (OR = 0.66, 95% CI: 0.53-0.82, P = 2.42×10-4) were negatively associated with KOA. In addition, our results showed that earlier AMP adversely affected HOA (OR = 1.12, 95% CI: 1.01-1.23, P = 0.033), and earlier ASOC promote the development of OOA (OR = 0.97, 95% CI: 0.95-1.00, P = 0.032) and KOA (OR = 0.58, 95% CI: 0.40-0.84, P = 4.49×10-3). ALB (OR = 0.98, 95% CI: 0.96-1.00, P = 0.030) and AFSI (OR = 0.98, 95% CI: 0.97-0.99, P = 2.66×10-3) also showed a negative association with OOA but they all did not pass multiple tests. The effects of AAM and NLB on OA were insignificant after BMI correction.

CONCLUSION

This research Certificates that Early AFB promotes the development of OOA, meanwhile early AFB, ALB, and AFSI are also risk factors of KOA. Reproductive factors, especially those related to birth, may have the greatest impact on KOA. It provides guidance for promoting women's appropriate age fertility and strengthening perinatal care.

Periprosthetic fractures are osteoporotic fractures: missed opportunities for osteoporosis diagnosis

Joint replacement surgery is common in older adults, leading to increasing periprosthetic fracture (PPFx) occurrence. We reviewed all PPFx seen over a 4-year period at an academic hospital. Clinical osteoporosis could be diagnosed based on existing data in 104 (67%) at the time of PPFx. Periprosthetic fractures are generally osteoporosis-related.

PURPOSE

Periprosthetic fractures (PPFx) cause morbidity, mortality, and cost. This study's purpose was to describe osteoporosis-related data available at the time of PPFx.

METHODS

The electronic medical record (EMR) of PPFx patients seen over 4 years in a university orthopedic practice were reviewed. Demographic data and osteoporosis relevant parameters were collected. Prior DXA studies were reviewed, and L1 Hounsfield unit (HU) measurements were performed on CT scans obtained within 2 years before PPFx. Clinical osteoporosis was defined as prior diagnosis, prescribed osteoporosis treatment, T-score ≤  - 2.5, HU ≤ 100, or prior fracture.

RESULTS

Records of 156 PPFx patients (115 F/41 M), mean (SD) age 75.4 (11.9), were reviewed. Almost all 153/156 (98%) of these fractures were femoral. Falls caused 139 (89%); 12 (8%) were spontaneous. Mean time post-arthroplasty was 7.9 (6.3) years. Prior fragility fracture(s) occurred in 72 (46%); 14 were PPFx. Osteoporosis was previously diagnosed in 45 (29%) and medications prescribed in 41 (26%). Prior to PPFx, DXA data were available in 62, mean (SD) lowest T-score was - 1.9 (0.9) and was ≤  - 2.5 in 19. CT data were available in 46; mean (SD) L1 HU was 79.0 (29.4) and was ≤ 100 in 35. Based on existing data, clinical osteoporosis could have been diagnosed in 104 (67%) at the time of PPFx.

CONCLUSION

Periprosthetic fractures are osteoporosis-related. They occur in older adults, often female, and result from falls; BMD, when assessed, is low. Data available at the time of PPFx often allows osteoporosis diagnosis; this should prompt evaluation and pharmacologic treatment consideration.

IGF-1 Genome-Edited Human MSCs Exhibit Robust Anti-Arthritogenicity in Collagen-Induced Arthritis

Stem cell therapy stands out as a promising avenue for addressing arthritis treatment. However, its therapeutic efficacy requires further enhancement. In this study, we investigated the anti-arthritogenic potential of human amniotic mesenchymal stem cells (AMM) overexpressing insulin-like growth factor 1 (IGF-1) in a collagen-induced mouse model. The IGF-1 gene was introduced into the genome of AMM through transcription activator-like effector nucleases (TALENs). We assessed the in vitro immunomodulatory properties and in vivo anti-arthritogenic effects of IGF-1-overexpressing AMM (AMM/I). Co-culture of AMM/I with interleukin (IL)-1β-treated synovial fibroblasts significantly suppressed NF-kB levels. Transplantation of AMM/I into mice with collagen-induced arthritis (CIA) led to significant attenuation of CIA progression. Furthermore, AMM/I administration resulted in the expansion of regulatory T-cell populations and suppression of T-helper-17 cell activation in CIA mice. In addition, AMM/I transplantation led to an increase in proteoglycan expression within cartilage and reduced infiltration by inflammatory cells and also levels of pro-inflammatory factors including cyclooxygenase-2 (COX-2), IL-1β, NF-kB, and tumor necrosis factor (TNF)-α. In conclusion, our findings suggest that IGF-1 gene-edited human AMM represent a novel alternative therapeutic strategy for the treatment of arthritis.

Prevotella histicola Prevented Particle-Induced Osteolysis via Gut Microbiota-Dependent Modulation of Inflammation in Ti-Treated Mice

Wear particles generated from total joint replacements induce chronic osteolysis mediated by inflammatory upregulation, which leads to implant failure. Recent studies have suggested an important role of the gut microbiota in modulating the host's metabolism and immune system, leading to alterations in bone mass. Following gavage with P. histicola, micro-CT and HE staining revealed that osteolysis was significantly reduced in titanium (Ti)-treated mice. Immunofluorescence analysis revealed an increased macrophage (M)1/M2 ratio in the guts of Ti-treated mice, which decreased when P. histicola was added. P. histicola was also found to upregulate the tight junction proteins ZO-1, occludin, claudin-1, and MUC2 in the gut, reduce the levels of inflammatory factors IL-1β, IL-6, IL-8, and TNF-α, primarily in the ileum and colon, and decrease the expression of IL-1β and TNF-α and increase the level of IL-10 in the serum and cranium. Furthermore, P. histicola treatment resulted in a significant downregulation of CTX-1, RANKL, and RANKL/OPG. These findings demonstrate that P. histicola significantly mitigates osteolysis in Ti-treated mice by improving intestinal microbiota that repairs intestinal leakage and reduces systemic and local inflammation which in turn inhibits RANKL expression for bone resorption. P. histicola treatment may thus be therapeutically beneficial for particle-induced osteolysis.

Withholding of Hormone Replacement Therapy Prior to Total Joint Arthroplasty Surgery to Reduce the Risk of Postoperative Thromboembolic Events: Is It Justified?-A Systematic Review of Clinical Practice Guidelines

BACKGROUND

Hormone replacement therapy (HRT), menopausal hormone therapy (MHT), and estrogen-containing medications are frequently withheld before elective lower limb arthroplasty, based on a perceived risk of venous thromboembolism (VTE). However, evidence linking HRT, MHT, and an increased VTE risk is equivocal. This systematic review evaluated the concordance of international clinical practice guidelines (CPGs) on the withholding of HRT or MHT.

METHODS

The PubMed, Google Scholar, Cochrane, and Ovid databases were searched for CPGs for the preoperative, perioperative, and postoperative management of patients on HRT and MHT undergoing elective lower limb arthroplasty. This was supplemented by an internet search. There were 7 international CPGs in English, from Europe and North America, published between January 2000 and February 2023 reviewed against the Appraisal of Guidelines for Research & Evaluation Instrument (AGREE-II) criteria, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

RESULTS

The guidelines reviewed revealed a mixed picture on HRT or MHT withdrawal and use in arthroplasty, with some featuring detailed advice on the preoperative and postoperative management of HRT or MHT (Scottish Intercollegiate Guidelines Network), while others featured no guidance (American College of Chest Physicians). The evidence referenced in these guidelines highlighted studies showing HRT or MHT to play a limited role in increasing VTE risk, with most studies from the 1990s and 2000s.

CONCLUSIONS

Based on current evidence, non-estrogen-containing transdermal HRT or MHT should not be withheld in patients undergoing elective joint arthroplasty, though further evidence is required to justify withholding estrogen-containing forms.

Integrative analysis of miRNA in cartilage-derived extracellular vesicles and single-cell RNA-seq profiles in knee osteoarthritis

Extracellular vesicular miRNAs (EV-miRNAs) play essential roles as intercellular communication molecules in knee Osteoarthritis (OA). We isolated cartilage-derived extracellular vesicles (EVs), to perform miRNA sequencing, which revealed EV-miRNA profiles and identified differentially expressed miRNAs (DE-miRNAs) between cartilage injury and cartilage non-injury groups. The target genes of known and novel DE-miRNAs were predicted with multiMiR package in 14 miRNA-target interaction databases. Meanwhile, single-cell RNA sequencing (scRNA-seq) was performed to identify chondrocyte clusters and their gene signatures in knee OA. Then we performed comparative analysis between target genes of the cartilage-derived EV-DE-miRNAs target genes and cluster-specific maker genes of characteristic chondrocyte clusters. Finally, the functional analysis of the cartilage-derived EVs DE-miRNA target genes and cluster-specific marker genes of each cell population were performed. The EV-miRNA profile analysis identified 13 DE-miRNAs and 7638 target genes. ScRNA-seq labelled seven clusters by cell type according to the expression of multiple characteristic markers. The results identified 735, 184, 303 and 879 common genes between EV-DE-miRNA target genes and cluster-specific marker genes in regulatory chondrocytes (RegCs), fibrocartilage chondrocytes (FC), prehypertrophic chondrocytes (PreHTCs) and mitochondrial chondrocytes (MTC), respectively. We firstly integrated the association between the cartilage-derived EV-DE-miRNA target genes and distinguished cluster-specific marker genes of each chondrocyte clusters. KEGG pathway analysis further identified that the DE-miRNAs target genes were significantly enriched in MAPK signaling pathway, Focal adhesion and FoxO signaling pathway. Our results provided some new insights into cartilage injury and knee OA pathogenesis which could improve the new diagnosis and treatment methods for OA.

Hormone replacement therapy does not increase thrombosis risk following THA: a national database study

PURPOSE

Hormone replacement therapy (HRT) causes a significant increase in the risk of venous thrombosis. The risk of medical and surgery-related complications among women taking HRT following total hip arthroplasty (THA) is poorly understood, and there are currently no guidelines in place regarding venous thromboembolism prophylaxis in this patient population. The purpose of this study was to evaluate the frequency of early medical and surgery-related complications following THA among women taking HRT.

METHODS

Women aged > 40 years of age who underwent primary THA were identified from a retrospective database review. A control group of non-HRT users was matched using propensity scoring to HRT users. Rates of 90-day medical complications and 1-year surgery-related complications were compared between cohorts using odds ratios. Postoperative anticoagulation regimens were also compared.

RESULTS

There were 3,936 patients in the HRT cohort who were matched to 39,360 patients not taking HRT. There were no significant differences in rates of DVT (OR 0.94, p = 0.6601) or PE (OR 0.80, p = 0.4102) between cohorts. Patients on HRT were more likely to sustain a dislocation (OR 1.35, p = 0.0269) or undergo revision surgery (OR 1.23, p = 0.0105). HRT patients were more likely to be prescribed warfarin (OR 1.21, p = 0.0001) or enoxaparin (OR 1.18, p = 0.0022) and less likely to be prescribed rivaroxaban (OR 0.62, p < 0.0001) compared to controls.

CONCLUSIONS

HRT was not found to be an independent risk factor for thromboembolism following THA. Further research is warranted to better delineate the ideal perioperative medical management of HRT users undergoing THA.

Periprosthetic fractures: an unrecognized osteoporosis crisis

Total joint replacement is common and increasing. Many of these patients have low bone mineral density preoperatively, and arthroplasty leads to bone loss. As falls are common before and after arthroplasty, it is unsurprising that periprosthetic fractures, defined as those associated with an orthopedic device, whether a joint replacement or other internal fixation devices, are not rare. These fractures engender morbidity and mortality comparable to osteoporosis-related hip fractures but remain largely unrecognized and untreated by osteoporosis/metabolic bone disease clinicians. Indeed, recent osteoporosis guidelines are silent regarding periprosthetic fractures. The purposes of this clinical review are to briefly describe the epidemiology of arthroplasty procedures and periprosthetic fractures, raise awareness that these fractures are osteoporosis-related, and suggest approaches likely to reduce their occurrence. Notably, bone health evaluation is essential following the occurrence of a periprosthetic fracture to reduce subsequent fracture risk. Importantly, in addition to such secondary fracture prevention, primary prevention, i.e., bone health assessment and optimization prior to elective orthopedic procedures, is appropriate.

Osteoarthritis: The importance of hormonal status in midlife women

Osteoarthritis (OA) is the commonest joint condition globally, affecting 18 % of women over the age of 60 years, although the prevalence varies according to the definition used. Although it may develop in any joint, it most commonly affects joints of the knee, hip, hand, spine and foot. Because OA often emerges in women in midlife, there has been longstanding interest in the association between hormonal status and the development and progression of OA. Researchers have variably suggested that estrogen exposure may be a risk factor for OA development, or that, conversely, it may be used as a therapy to treat OA. This review considers the historical development of this question, first described in the literature in 1805, and highlights the need for future research in this area.

Single-cell RNA-sequencing analysis reveals the molecular mechanism of subchondral bone cell heterogeneity in the development of osteoarthritis

The cellular composition and underlying spatiotemporal transformation processes of subchondral bone in osteoarthritis (OA) remain unknown. Herein, various cell subsets from tibial plateau of patients with OA are identified, and the mechanism of subchondral microstructure alteration is elaborated using single-cell RNA sequencing technique. We identified two novel endothelial cell (EC) populations characterised by either exosome synthesis and inflammation response or vascular function and angiogenesis. Three osteoblast (OB) subtypes are introduced, separately related to vascularisation, matrix manufacturing and matrix mineralisation. The distinct roles and functions of these novel phenotypes in OA development are further discussed as well as interaction network between these subpopulations. The variation tendency of each population is testified in a destabilisation of the medial meniscus mouse model. The identification of cell types demonstrates a novel taxonomy and mechanism for ECs and OBs inside subchondral bone area provides new insights into the physiological and pathological behaviours of subchondral bone in OA pathogenesis.

3D printing monetite-coated Ti-6Al-4V surface with osteoimmunomodulatory function to enhance osteogenesis

Titanium and its alloys are widely used in orthopedic implant surgery due to their good mechanical properties and biocompatibility. Recent studies have shown that the healing process of fractures involve not only the calcification of osteoblasts but also the regulation of the immune system. The functionalization of titanium surface coatings is one of the most important methods for solving implant failures. In this study, monetite (CaHPO₄) was coated on the Ti-6Al-4V porous scaffold by hydrothermal method. SEM, XRD and EDS were used to characterize the morphology, phase constitutes, elemental content of the coating, respectively. The results indicated that a well bonded and uniformly distributed monetite coating obtained, and the degradation performance and Ca²⁺ release of the surface coating were also studied. In terms of biology, live/dead staining and CCK8 methods showed the coating had good biocompatibility and BMSCs can adhere and proliferate on the surface. Flow cytometry and ELISA indicated that the surface monetite-coating had good anti-inflammatory properties. Through RNA-seq analysis, it was shown in KEGG that the osteoclast-related pathway was inhibited. In vitro, monetite induced osteogenic gene expression in BMSCs and inhibited the activity of osteoclasts. In vivo experiments showed that the monetite-coating increased bone formation. In summary, monetite-coating can effectively promote the osteogenesis in BMSCs, which may be achieved through bone immune regulation.

Sex Steroids and Osteoarthritis: A Mendelian Randomization Study

Objective

Sex steroids are thought to contribute to the pathogenesis of osteoarthritis (OA). This study investigated the causal role of sex steroids in site- and sex-specific OA and risk of joint replacement surgery using the Mendelian randomization (MR) method.

Methods

Instrumental variables for estradiol, dehydroepiandrosterone sulfate, testosterone (T), and dihydrotestosterone (DHT) were selected. We used the inverse variance weighting (IVW) approach as the main MR method to estimate causal effects based on the summary-level data for OA and joint replacement surgery from genome-wide association studies (GWAS).

Results

A positive causal association was observed between serum T level and risks of hip OA (odds ratio [OR]=1.558, 95% confidence interval [CI]: 1.193-2.034; P=0.001) and hip replacement (OR=1.013, 95% CI: 1.008-1.018; P=2.15×10-8). Serum DHT level was also positively associated with the risk of hip replacement (OR=1.011, 95% CI: 1.006-1.015; P=4.03×10-7) and had potential causality with hip OA (OR=1.398, 95% CI: 1.054-1.855; P=0.020).

Conclusions

Serum T and DHT levels may play causal roles in the development of hip OA and contribute to the risk of hip replacement, although the underlying mechanisms require further investigation.

Estrogen Regulation of the Expression of Pain Factor NGF in Rat Chondrocytes

OBJECTIVE

Pain is the main symptom of osteoarthritis (OA). Nerve growth factor (NGF) plays a crucial role in the generation of OA pain. And estrogen-alone used resulted in a sustained joint pain reduction in postmenopausal women. So we aim to find whether estrogen alters chondrocytes' NGF level, affecting OA pain.

METHODS

Primary chondrocytes and cartilage explants isolated from Sprague Dawley rat knees were cultured with physiological concentrations of estrogen (17β-Estradiol ≥ 98%, E2), Estrogen Receptor α (ERα) inhibitor and stimulants. Then, chondrocytes NGF mRNA expression and protein release were analyzed by a quantitative real-time polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) respectively. Additionally, cultures were pre-incubated with MEK-ERK inhibitor to identify the signaling pathway that estrogen alters NGF mRNA and protein levels.

RESULTS

We found that chondrocytes NGF expression and release were decreased by E2. E2 also reduced chondrocytes IL-1β-stimulated or TGF-β1-stimulated NGF expression. Phosphorylated extracellular signal-regulated kinasep1/2 (p-ERK1/2) signals were detected stronger than the control group by Western Blotting (WB). When we cultured chondrocytes with PD98059 (MEK-ERK inhibitor, PD), NGF mRNA expression was added to 1.41Ct (2.07±0.1 fold).

CONCLUSION

We showed that E2 reduces chondrocytes NGF expression significantly, even after stimulation by TGF-β1 or IL-1β. MEK-ERK signaling is involved in this process.

Bisphosphonates to reduce bone fractures in stage 3B+ chronic kidney disease: a propensity score-matched cohort study

BACKGROUND

Bisphosphonates are contraindicated in patients with stage 4+ chronic kidney disease. However, they are widely used to prevent fragility fractures in stage 3 chronic kidney disease, despite a lack of good-quality data on their effects.

OBJECTIVES

The aims of each work package were as follows. Work package 1: to study the relationship between bisphosphonate use and chronic kidney disease progression. Work package 2: to study the association between using bisphosphonates and fracture risk. Work package 3: to determine the risks of hypocalcaemia, hypophosphataemia, acute kidney injury and upper gastrointestinal events associated with using bisphosphonates. Work package 4: to investigate the association between using bisphosphonates and changes in bone mineral density over time.

DESIGN

This was a new-user cohort study design with propensity score matching.

SETTING AND DATA SOURCES

Data were obtained from UK NHS primary care (Clinical Practice Research Datalink GOLD database) and linked hospital inpatient records (Hospital Episode Statistics) for work packages 1-3 and from the Danish Odense University Hospital Databases for work package 4.

PARTICIPANTS

Patients registered in the data sources who had at least one measurement of estimated glomerular filtration rate of < 45 ml/minute/1.73 m2 were eligible. A second estimated glomerular filtration rate value of < 45 ml/minute/1.73 m2 within 1 year after the first was requested for work packages 1 and 3. Patients with no Hospital Episode Statistics linkage were excluded from work packages 1-3. Patients with < 1 year of run-in data before index estimated glomerular filtration rate and previous users of anti-osteoporosis medications were excluded from work packages 1-4.

INTERVENTIONS/EXPOSURE

Bisphosphonate use, identified from primary care prescriptions (for work packages 1-3) or pharmacy dispensations (for work package 4), was the main exposure.

MAIN OUTCOME MEASURES

Work package 1: chronic kidney disease progression, defined as stage worsening or starting renal replacement. Work package 2: hip fracture. Work package 3: acute kidney injury, hypocalcaemia and hypophosphataemia identified from Hospital Episode Statistics, and gastrointestinal events identified from Clinical Practice Research Datalink or Hospital Episode Statistics. Work package 4: annualised femoral neck bone mineral density percentage change.

RESULTS

Bisphosphonate use was associated with an excess risk of chronic kidney disease progression (subdistribution hazard ratio 1.12, 95% confidence interval 1.02 to 1.24) in work package 1, but did not increase the probability of other safety outcomes in work package 3. The results from work package 2 suggested that bisphosphonate use increased fracture risk (hazard ratio 1.25, 95% confidence interval 1.13 to 1.39) for hip fractures, but sensitivity analyses suggested that this was related to unresolved confounding. Conversely, work package 4 suggested that bisphosphonates improved bone mineral density, with an average 2.65% (95% confidence interval 1.32% to 3.99%) greater gain in femoral neck bone mineral density per year in bisphosphonate users than in matched non-users.

LIMITATIONS

Confounding by indication was a concern for the clinical effectiveness (i.e. work package 2) data. Bias analyses suggested that these findings were due to inappropriate adjustment for pre-treatment risk. work packages 3 and 4 were based on small numbers of events and participants, respectively.

CONCLUSIONS

Bisphosphonates were associated with a 12% excess risk of chronic kidney disease progression in participants with stage 3B+ chronic kidney disease. No other safety concerns were identified. Bisphosphonate therapy increased bone mineral density, but the research team failed to demonstrate antifracture effectiveness.

FUTURE WORK

Randomised controlled trial data are needed to demonstrate antifracture efficacy in patients with stage 3B+ chronic kidney disease. More safety analyses are needed to characterise the renal toxicity of bisphosphonates in stage 3A chronic kidney disease, possibly using observational data.

STUDY REGISTRATION

This study is registered as EUPAS10029.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 17. See the NIHR Journals Library website for further project information. The project was also supported by the National Institute for Health Research Biomedical Research Centre, Oxford.

The Association of Calcium and Vitamin D Use With Implant Survival of Total Knee Arthroplasty: A Nationwide Population-Based Cohort Study

BACKGROUND

Calcium and vitamin D have been regarded as beneficial nutrients for bone metabolism that may affect survival of arthroplasties. However, the relationship between their use and revision rate of knee arthroplasty has not been evaluated. Thus, we investigated an association between calcium and vitamin D use and the revision rate after primary total knee arthroplasty.

METHODS

A nationwide population-based cohort study was conducted using the Korean National Health Insurance database. We included patients diagnosed with knee osteoarthritis and underwent primary total knee arthroplasty between 2009 and 2018. Risk for arthroplasty revision was estimated using a Cox proportional hazards model with time-dependent covariates. Log-rank test was used to assess survival of knee arthroplasty.

RESULTS

Out of 142,147 subjects, 28,403 were calcium and vitamin D users and 113,744 were never users. Calcium and vitamin D significantly reduced the revision risk with a 6-month drug use lag period (adjusted hazard ratio [aHR] 0.56, 95% confidence interval [CI] 0.45-0.70). Calcium and vitamin D combination use for more than 1 year was associated with reduced revision risks in both patients with periprosthetic joint infection (aHR 0.63, 95% CI 0.42-0.95) and patients without infection (aHR 0.70, 95% CI 0.54-0.91). Implant survival was significantly improved in calcium and vitamin D combination users for more than 1 year compared with never users (log-rank P < .001).

CONCLUSION

Combination use of calcium and vitamin D with a dose of 800 IU or greater for more than 1 year was associated with the greatest reduction in the risks for revision surgery after total knee arthroplasty.

Raloxifene Prevents Early Periprosthetic Bone Loss for Postmenopausal Women after Uncemented Total Hip Arthroplasty: A Randomized Placebo-Controlled Clinical Trial

OBJECTIVE

To examine the results of raloxifene for prevention of periprosthetic bone loss around the femoral stem in patients undergoing total hip arthroplasty (THA).

METHODS

Between January 2015 and May 2017, 240 female patients between 55 and 80 years underwent primary THA and were randomly allocated to receive 60 mg raloxifene hydrochloride per day (treatment group, TG, n = 120) or placebo (control group, CG, n = 120) orally at bedtime using computer-generated randomization sequence generation. Baseline data, the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), women's quality of life (QoL) score, bone mineral density (BMD) around the prosthesis, and adverse events were compared between the two groups. The measuring range of BMD around the prosthesis was divided into seven regions of interest (ROI). The sample size was calculated to detect a mean difference in BMD of 0.15 g/cm² with a standard deviation (SD) of 0.3. The error was set at 0.05 and the power level at 90% with additional compensation for a possible dropout rate of 20%.

RESULTS

A total of 240 participants in the study up to 24 months after THA. There were no significant differences in the mean BMD of all the zones between groups before surgery (all P > 0.05). However, there were significant differences in the BMD of Gruen zones 4 and 7 between groups at 6 months postoperatively (both P < 0.05); there were significant differences in Gruen zones 1, 4, 6, and 7 at 12 months postoperatively (all P < 0.01); there were significant differences in Gruen zones 1, 2, 4, 6, and 7 at 24 months postoperatively (all P < 0.001). Patients taking raloxifene reported higher QoL scores, with better improvement in BMD in all areas except in zones 3 and 5 compared with the control group. There were no significant differences in WOMAC pain (P = 0.4045), WOMAC function (P = 0.4456) and women's QoL scores (P = 0.5983) between groups before surgery. However, WOMAC pain, WOMAC function and women's QoL score in the treatment group were significantly better at all time points (all P < 0.05). Patients in the treatment group showed no increased adverse events, including cardiac events, stroke, venous thromboembolism, and gynecological cancer (all P > 0.05), but did show decreased odds of breast cancer in comparison with those using a placebo (P = 0.0437).

CONCLUSION

Raloxifene can help inhibit bone loss around the prosthesis and improve the QoL of postmenopausal women after THA with no increased adverse events, and can even decrease the odds of breast cancer.

Effect of Timing and Duration of Statin Exposure on Risk of Hip or Knee Revision Arthroplasty: A Population-based Cohort Study

OBJECTIVES

To determine whether the timing and duration of statin exposure following total hip/knee arthroplasty (THA/TKA) influence the risk of revision arthroplasty.

METHODS

Subjects from the Clinical Practice Research Datalink, a large population-based clinical database, who had THA/TKA from 1988 to 2016, were included. Propensity score adjusted Cox regression models were used to determine the association between statin exposure and the risk of revision THA/TKA, (1) at any time, and (2) if first exposed 0-1, 1-5, or > 5 years following THA/TKA. We also investigated the effect of duration of statin exposure (< 1, 1-2, 2-3, 3-4, 4-5, > 5 yrs).

RESULTS

The study included 151,305 participants. There were 65,032 (43%) exposed to statins during followup and 3500 (2.3%) had revision arthroplasty. In a propensity score adjusted model, exposure to statins was associated with a reduced risk of revision arthroplasty (HR 0.82, 95% CI 0.75-0.90). Participants first exposed within 1 year and between 1 and 5 years following THA/TKA (vs unexposed) had a reduced risk of revision arthroplasty (HR 0.82, 95% CI 0.74-0.91 and HR 0.76, 95% CI 0.65-0.90, respectively). In relation to duration of statin therapy, participants exposed for more than 5 years in total (vs < 1 yr) had a reduced risk of revision (HR 0.74, 95% CI 0.62-0.88).

CONCLUSION

Statin therapy initiated up to 5 years following THA/TKA may reduce the risk of revision arthroplasty.

Single-cell RNA-seq analysis reveals the progression of human osteoarthritis

OBJECTIVES

Understanding the molecular mechanisms underlying human cartilage degeneration and regeneration is helpful for improving therapeutic strategies for treating osteoarthritis (OA). Here, we report the molecular programmes and lineage progression patterns controlling human OA pathogenesis using single-cell RNA sequencing (scRNA-seq).

METHODS

We performed unbiased transcriptome-wide scRNA-seq analysis, computational analysis and histological assays on 1464 chondrocytes from 10 patients with OA undergoing knee arthroplasty surgery. We investigated the relationship between transcriptional programmes of the OA landscape and clinical outcome using severity index and correspondence analysis.

RESULTS

We identified seven molecularly defined populations of chondrocytes in the human OA cartilage, including three novel phenotypes with distinct functions. We presented gene expression profiles at different OA stages at single-cell resolution. We found a potential transition among proliferative chondrocytes, prehypertrophic chondrocytes and hypertrophic chondrocytes (HTCs) and defined a new subdivision within HTCs. We revealed novel markers for cartilage progenitor cells (CPCs) and demonstrated a relationship between CPCs and fibrocartilage chondrocytes using computational analysis. Notably, we derived predictive targets with respect to clinical outcomes and clarified the role of different cell types for the early diagnosis and treatment of OA.

CONCLUSIONS

Our results provide new insights into chondrocyte taxonomy and present potential clues for effective and functional manipulation of human OA cartilage regeneration that could lead to improved health.

Auricular Point Acupressure to Manage Aromatase Inhibitor-Induced Arthralgia in Postmenopausal Breast Cancer Survivors: A Pilot Study

PURPOSE/OBJECTIVES

To assess the feasibility of auricular point acupressure to manage aromatase inhibitor-induced arthralgia.
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DESIGN

Wait list control design.
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SETTING

Outpatient clinics and oncology center.
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SAMPLE

20 women with aromatase inhibitor-induced arthralgia.
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METHODS

After baseline data were collected, participants waited one month before they received acupressure once per week for four weeks at a convenient time. The baseline data served as the control comparison. Self-reported measures and blood samples were obtained at baseline, at preintervention, weekly during the intervention, and at post-intervention.
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MAIN RESEARCH VARIABLES

The primary outcomes included pain intensity, pain interference, stiffness, and physical function. Inflammatory cytokines and chemokines were tested.
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FINDINGS

After the four-week intervention, participants reported decreases in worst pain and pain interference, and improvements in physical function, cancer-related symptom severity, and interference. The proinflammatory cytokines and chemokines displayed a trend of a mean percentage reduction. The anti-inflammatory cytokine interleukin-13 increased from pre- to postintervention.
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CONCLUSIONS

Auricular point acupressure is feasible and may be effective in managing arthralgia in breast cancer survivors.
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IMPLICATIONS FOR NURSING

Nurses can administer acupressure in clinical settings, which could enhance the management of aromatase inhibitor-induced arthralgia and contribute to a shift from traditional disease-based biomedical models to a broader, integrative, medical paradigm for managing aromatase inhibitor-induced arthralgia.

Effect of bisphosphonates on knee replacement surgery

PURPOSE

Bone remodelling as a therapeutic target in knee osteoarthritis (OA) has gained much interest, but the effects of antiresorptive agents on knee OA have been conflicting, with no studies to date examining the effects of bisphosphonate use on the clinically relevant endpoint of knee replacement (KR) surgery.

METHODS

We used data from The Health Improvement Network (THIN), a general practitioner electronic medical records representative of the general UK population. We identified older women who had initiated bisphosphonate use after their incident knee OA diagnosis. Each bisphosphonate initiator was propensity score-matched with a non-initiator within each 1-year cohort accrual block. The effect of bisphosphonates on the risk of KR was assessed using Cox proportional hazard regression. Sensitivity analyses to address residual confounding were also conducted.

RESULTS

We identified 2006 bisphosphonate initiators, who were matched to 2006 non-initiators(mean age 76, mean body mass index 27), with mean follow-up time of 3 years. The crude incidence rate of KR was 22.0 per 1000 person-years among the initiators, and 29.1 among the non-initiators. Bisphosphonate initiators had 26% lower risk of KR than non-initiators(HR 0.74, 95% CI 0.59 to 0.93); these results were similar when additionally adjusted for potential confounders in the propensity score (HR 0.76, 95% CI 0.60 to 0.95). Results of sensitivity analyses supported this protective effect.

CONCLUSIONS

In this population-based cohort of older women with incident knee OA, those with incident bisphosphonate users had lower risk of KR than non-users of bisphosphonates, suggesting a potential beneficial effect of bisphosphonates on knee OA.

Cross-Coupling Effects of Silencing of Cyclooxygenase-2 (COX-2)/Aggrecanase-1 and Over-Expressed Insulin-Like Growth Factor 1 (IGF-1) in an Osteoarthritis Animal Model

BACKGROUND This study aimed to observe the effect of lentivirus-mediated cyclooxygenase-2 and aggrecanase-1 silencing and insulin-like growth factor-1 overexpression in human bone marrow mesenchymal stem cells after injection into model osteoarthritic knees. MATERIAL AND METHODS Using genetic recombination technique, the genes of cyclooxygenase-2, aggrecanase-1, and insulin-like growth factor-1 were recombined into the lentiviral vectors, and we transfected the human bone marrow stem cells in vitro. The BMSC transfected with lentivirus without genes served as a blank-virus group, and saline was used for another control group. One week later, the cytokines PGE2, aggrecanase-1, hIGF-1, and IL-1 were detected and compared between groups. RESULTS Compared with blank-virus group, the expression of COX-2 (85.81±5.12 ng/L) and aggrecanase1 (6.256±1.66) were decreased in the virus group (p<0.05), while the expression of hIGF-1 (17.46±1.86) was increased (p<0.05). The concentrations of PGE2 (85.81±5.12 ng/L), aggrecanase1 (51.34±5.463 ng/L), and IL-1 (82.31±4.321 ng/L) decreased (p<0.05) within the knee, but the concentration of hIGF-1 (44.33±0.7194 ng/L) increased (p<0.05). Compared with the other groups, the results of histological and immunohistochemical examinations demonstrated that the abrasion of articular cartilage was significantly improved and repaired. CONCLUSIONS Lentivirus-mediated RNAi can inhibit the expression of COX-2 mRNA and aggrecanase-1mRNA, and enhance the hIGF-1 mRNA expression, thereby influencing the concentration of cytokines in the early osteoarthritic model knee joints.

Association between NICE guidance on biologic therapies with rates of hip and knee replacement among rheumatoid arthritis patients in England and Wales: An interrupted time-series analysis

OBJECTIVE

To estimate the impact of NICE approval of tumor necrosis factor inhibitor (TNFi) therapies on the incidence of total hip replacement (THR) and total knee replacement (TKR) among rheumatoid arthritis (RA) patients in England and Wales.

METHODS

Primary care data [Clinical Practice Research Datalink (CPRD)] for the study period (1995-2014) were used to identify incident adult RA patients. The age and sex-standardised 5-year incidence of THR and TKR was calculated separately for RA patients diagnosed in each six-months between 1995-2009. We took a natural experimental approach, using segmented linear regression to estimate changes in level and trend following the publication of NICE TA 36 in March 2002, incorporating a 1-year lag. Regression coefficients were used to calculate average change in rates, adjusted for prior level and trend.

RESULTS

We identified 17,505 incident RA patients of whom 465 and 650 underwent THR and TKR surgery, respectively. The modeled average incidence of THR and TKR over the biologic-era was 6.57/1000 person years (PYs) and 8.51/1000 PYs, respectively, with projected (had pre-NICE TA 36 level and trend continued uninterrupted) figures of 5.63/1000 PYs and 12.92 PYs, respectively. NICE guidance was associated with a significant average decrease in TKR incidence of -4.41/1000 PYs (95% C.I. -6.88 to -1.94), equating to a relative 34% reduction. Overall, no effect was seen on THR rates.

CONCLUSIONS

Among incident RA patients in England and Wales, NICE guidance on TNFi therapies for RA management was temporally associated with reduced rates of TKR but not THR.

Lower limb arthroplasty: can we produce a tool to predict outcome and failure, and is it cost-effective? An epidemiological study

Background

Although hip and knee arthroplasties are considered to be common elective cost-effective operations, up to one-quarter of patients are not satisfied with the operation. A number of risk factors for implant failure are known, but little is known about the predictors of patient-reported outcomes.

Objectives

(1) Describe current and future needs for lower limb arthroplasties in the UK; (2) describe important risk factors for poor surgery outcomes and combine them to produce predictive tools (for hip and knee separately) for poor outcomes; (3) produce a Markov model to enable a detailed health economic analysis of hip/knee arthroplasty, and for implementing the predictive tool; and (4) test the practicality of the prediction tools in a pragmatic prospective cohort of lower limb arthroplasty.

Design

The programme was arranged into four work packages. The first three work packages used the data from large existing data sets such as Clinical Practice Research Datalink, Hospital Episode Statistics and the National Joint Registry. Work package 4 established a pragmatic cohort of lower limb arthroplasty to test the practicality of the predictive tools developed within the programme.

Results

The estimated number of total knee replacements (TKRs) and total hip replacements (THRs) performed in the UK in 2015 was 85,019 and 72,418, respectively. Between 1991 and 2006, the estimated age-standardised rates (per 100,000 person-years) for a THR increased from 60.3 to 144.6 for women and from 35.8 to 88.6 for men. The rates for TKR increased from 42.5 to 138.7 for women and from 28.7 to 99.4 for men. The strongest predictors for poor outcomes were preoperative pain/function scores, deprivation, age, mental health score and radiographic variable pattern of joint space narrowing. We found a weak association between body mass index (BMI) and outcomes; however, increased BMI did increase the risk of revision surgery (a 5-kg/m2rise in BMI increased THR revision risk by 10.4% and TKR revision risk by 7.7%). We also confirmed that osteoarthritis (OA) severity and migration pattern of the hip predicted patient-reported outcome measures. The hip predictive tool that we developed performed well, with a correctedR2of 23.1% and had good calibration, with only slight overestimation of Oxford Hip Score in the lowest decile of outcome. The knee tool developed performed less well, with a correctedR2of 20.2%; however, it had good calibration. The analysis was restricted by the relatively limited number of variables available in the extant data sets, something that could be addressed in future studies. We found that the use of bisphosphonates reduced the risk of revision knee and hip surgery by 46%. Hormone replacement therapy reduced the risk by 38%, if used for at least 6 months postoperatively. We found that an increased risk of postoperative fracture was prevented by bisphosphonate use. This result, being observational in nature, will require confirmation in a randomised controlled trial. The Markov model distinguished between outcome categories following primary and revision procedures. The resulting outcome prediction tool for THR and TKR reduced the number and proportion of unsatisfactory outcomes after the operation, saving NHS resources in the process. The highest savings per quality-adjusted life-year (QALY) forgone were reported from the oldest patient subgroups (men and women aged ≥ 80 years), with a reported incremental cost-effectiveness ratio of around £1200 saved per QALY forgone for THRs. In the prospective cohort of arthroplasty, the performance of the knee model was modest (R2 = 0.14) and that of the hip model poor (R2 = 0.04). However, the addition of the radiographic OA variable improved the performance of the hip model (R2 = 0.125 vs. 0.110) and high-sensitivity C-reactive protein improved the performance of the knee model (R2 = 0.230 vs. 0.216). These data will ideally need replication in an external cohort of a similar design. The data are not necessarily applicable to other health systems or countries.

Conclusion

The number of total hip and knee replacements will increase in the next decade. High BMI, although clinically insignificant, is associated with an increased risk of revision surgery and postoperative complications. Preoperative pain/function, the pattern of joint space narrowing, deprivation index and level of education were found to be the strongest predictors for THR. Bisphosphonates and hormone therapy proved to be beneficial for patients undergoing lower limb replacement. The addition of new predictors collected from the prospective cohort of arthroplasty slightly improved the performance of the predictive tools, suggesting that the potential improvements in both tools can be achieved using the plethora of extra variables from the validation cohort. Although currently it would not be cost-effective to implement the predictive tools in a health-care setting, we feel that the addition of extensive risk factors will improve the performances of the predictive tools as well as the Markov model, and will prove to be beneficial in terms of cost-effectiveness. Future analyses are under way and awaiting more promising provisional results.

Future work

Further research should focus on defining and predicting the most important outcome to the patient.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Implication of different initial beta blockers on treatment persistence: atenolol vs new-generation beta blocker, a population-based study

AIM

Potential heterogeneity within the same class of drug in terms of persistence may lead to different clinical implications. Given that the increased risks of mortality and cardiovascular events are due, in part, to the lack of persistent use of antihypertensive medications, the objective of this study was to evaluate 1-year persistence of new-generation beta blockers compared to atenolol in antihypertensive treatment-naïve patients.

METHODS

A total of 9978 patients aged 18 years or older with hypertension newly diagnosed in 2012, without hypertension-related complication and initiated treatment with beta blocker monotherapy during 2012 were included in the analysis. Rate and duration of treatment and drug persistence were compared between atenolol and new-generation beta blockers. Hazards of discontinuation in nonatenolol compared to atenolol were evaluated using a multivariate Cox proportional model.

RESULTS

The rate of treatment persistence was higher in the nonatenolol group (57.35% vs 53.40%, P<.0001), and the time to treatment discontinuation was earlier in the atenolol group with a minimal difference in the average (243.2 vs 254 days, P<.0001). New-generation beta blockers demonstrated a lower risk of treatment discontinuation (HR: 0.91, 95% CI: 0.86-0.96) compared to atenolol; a notable improvement was observed with carvedilol and nebivolol (HR: 0.74, 95% CI: 0.69-0.80 and HR: 0.79, 95% CI: 0.70-0.89, respectively), whereas betaxolol showed a substantially greater hazard for discontinuation compared to atenolol.

CONCLUSIONS

This study demonstrated a meaningful improvement in treatment persistence with new-generation beta blockers compared to atenolol, with betaxolol as exception.

Clinical settings in knee osteoarthritis: Pathophysiology guides treatment

Osteoarthritis (OA) is the most common chronic joint disorder and its prevalence increases rapidly during midlife. Complex interactions of genetic alterations, sex hormone deficit, and aging with mechanical factors and systemic inflammation-associated metabolic syndrome lead to joint damage. Thus, the expression of a clinical phenotype in the early stages of OA relies on the main underlying pathway and predominant joint tissue involved at a given time. Moreover, OA often coexists with other morbidities in the same patient, which in turn condition the OA process. In this scenario, an appropriate identification of clinical phenotypes, especially in the early stages of the disease, may optimize the design of individualized treatments in OA. An ESCEO-EUGMS (European Union Geriatric Medicine Society) working group has recently suggested possible patient profiles in OA. Hereby, we propose the existence of 4 clinical phenotypes - biomechanical, osteoporotic, metabolic and inflammatory - whose characterization would help to properly stratify patients with OA in clinical trials or studies. Further research in this field is warranted.

Clinical Factors, Disease Parameters, and Molecular Therapies Affecting Osseointegration of Orthopedic Implants

Total hip and knee arthroplasty are effective interventions for management of end-stage arthritis. Indeed, about 7 million Americans are currently living with artificial hip and knee joints. The majority of these individuals, however, will outlive their implants and require revision surgeries, mostly due to poor implant osseointegration and aseptic loosening. Revisions are potentially avoidable with better management of patient-related risk factors that affect the osseointegration of orthopedic implants. In this review, we summarize the published clinical literature on the role of demographics, biologic factors, comorbidities, medications and aseptic loosening risk. We focus on several systemic and local factors that are particularly relevant to implant osseointegration. Examples include physiological and molecular processes that are linked to hyperglycemia, oxidative stress, metabolic syndrome and dyslipidemia. We discuss how orthopedic implant osseointegration can be affected by a number of molecular therapies that are antiresorptive or bone anabolic (i.e. calcium, vitamin D, bisphosphonates, calcitonin, strontium, hormone replacement therapy, selective estrogen-receptor modulators).

Comparison of Statistical Approaches for Dealing With Immortal Time Bias in Drug Effectiveness Studies

In time-to-event analyses of observational studies of drug effectiveness, incorrect handling of the period between cohort entry and first treatment exposure during follow-up may result in immortal time bias. This bias can be eliminated by acknowledging a change in treatment exposure status with time-dependent analyses, such as fitting a time-dependent Cox model. The prescription time-distribution matching (PTDM) method has been proposed as a simpler approach for controlling immortal time bias. Using simulation studies and theoretical quantification of bias, we compared the performance of the PTDM approach with that of the time-dependent Cox model in the presence of immortal time. Both assessments revealed that the PTDM approach did not adequately address immortal time bias. Based on our simulation results, another recently proposed observational data analysis technique, the sequential Cox approach, was found to be more useful than the PTDM approach (Cox: bias = -0.002, mean squared error = 0.025; PTDM: bias = -1.411, mean squared error = 2.011). We applied these approaches to investigate the association of β-interferon treatment with delaying disability progression in a multiple sclerosis cohort in British Columbia, Canada (Long-Term Benefits and Adverse Effects of Beta-Interferon for Multiple Sclerosis (BeAMS) Study, 1995-2008).

Total joint arthroplasty and the risk of myocardial infarction: a general population, propensity score-matched cohort study

OBJECTIVE

To replicate recent findings indicating that total knee arthroplasty (TKA) or total hip arthroplasty (THA) surgery will substantially reduce the risk of serious cardiovascular events among patients with osteoarthritis.

METHODS

A time-stratified, propensity score-matched cohort study was conducted to assess the incidence of myocardial infarction (MI) in a UK general population. The study population included individuals ages ≥50 years who had a UK National Health Service READ code diagnosis of knee osteoarthritis (to evaluate TKA) or hip osteoarthritis (to evaluate THA) between January 2000 and December 2012.

RESULTS

Among the patients who underwent TKA and their matched non-TKA control subjects (each n = 13,849), 306 patients and 286 control subjects developed MI during the followup. During the first postoperative month, the risk of MI was substantially increased among the TKA group compared with the non-TKA group (hazard ratio [HR] 8.75, 95% confidence interval [95% CI] 3.11-24.62), and then gradually declined during the subsequent followup. The HR for the risk of MI over the entire followup was 0.98 (95% CI 0.82-1.18). The corresponding HRs for the risk of MI in those who had undergone THA compared with the non-THA group (each n = 6,063) were 4.33 (95% CI 1.24-15.21) in the first postoperative month and 0.87 (95% CI 0.66-1.15) overall. In analyses using venous thromboembolism as a positive control outcome, both the first month and overall HRs for the risk of venous thromboembolism were substantially increased in both the TKA and THA groups.

CONCLUSION

These findings provide the first general population-based evidence to indicate that TKA and THA among osteoarthritis patients are associated with a substantially increased risk of MI during the immediate postoperative period. However, the overall long-term impact of these surgeries was null, unlike the risk of venous thromboembolism, which remained elevated years after patients had undergone the procedure.