GENETIC FACTORS IN GENERALIZED OSTEO-ARTHROSIS

Osteoarthritis

The clinical appearance and radiological pattern of osteoarthritis have been identified in the skeletons of dinosaurs some 50-70 million years old, and in Egyptian mummies, and in ancient skeletons in England. Osteoarthritis patterns of joint involvement, often referred to as primary osteoarthritis, can be seen in the hands, spinal facet joints, hips, knees and feet, but can also be termed secondary osteoarthritis when seen in any joint that has had trauma, sepsis, surgery or metabolic insult. The prevalence of osteoarthritis increases with age. The histology and pathophysiology both demonstrate an inflammatory process. While there have been studies of genetic predisposition, the basic cause of primary osteoarthritis has not been determined.

Osteoarthritis of the Knee in Middle-age Athletes: Many Measures are Practiced, but Lack Sound Scientific Evidence

Osteoarthritis of the knee generally affects individuals from the fifth decade, the typical age of middle-age athletes. In the early stages, management is conservative and multidisciplinary. It is advisable to avoid sports with high risk of trauma, but it is important that patients continue to be physically active. Conservative management offers several options; however, it is unclear which ones are really useful. This narrative review briefly reports the conservative options for which there is no evidence of effectiveness, or there is only evidence of short-term effectiveness.

Incidence and risk factors for poor ankle functional recovery, and the development and progression of posttraumatic ankle osteoarthritis after significant ankle ligament injury (SALI): the SALI cohort study protocol

Background

Ankle sprains are one of the most common musculoskeletal injuries, accounting for up to 5% of all Emergency Department visits in the United Kingdom. Ankle injury may be associated with future ankle osteoarthritis. Up to 70% of ankle osteoarthritis cases may be associated with previous ankle injury. There is limited research regarding the association between ankle sprain and ankle osteoarthritis development. The current study aims to phenotype those who suffer significant ankle ligament injuries, identify potential risk factors for ankle injuries and subsequent poor recovery, examine why individuals may develop osteoarthritis, and what factors influence this chance.

Methods

In this multicentre cohort study participants were recruited from nine Emergency Departments and two Urgent Care Centres in the United Kingdom. Participants (aged 18–70 years old) were defined as those who had suffered an isolated acute ankle sprain, which was Ottawa Ankle Rules positive, but negative for a significant ankle fracture on x-ray. Age and sex matched controls were also recruited. The controls were individuals who had not suffered a significant ankle injury, including ankle pain, function affected for more than 7 days, or the ankle caused them to report to an Emergency Department. Data is collected through a series of seven questionnaires (at baseline, 3 months, 1 year, 3 years, 5 years, 10 years, and 15 years later). The questionnaires include four sections (demographic questions; index injury, and injury history questions; functional assessment questions; and quality of life questions) and are designed to collect detailed information about the individual, their injury, potential risk factors for ankle sprains and ankle osteoarthritis, plus their medical history and any medication consumed.

Discussion

The Significant Ankle Ligament Injury (SALI) study aims to add to the limited knowledge regarding which factors can predict ankle sprains, complaints, and osteoarthritis. This is important because despite ankle sprains being regarded as a benign injury that resolves quickly, residual symptoms are not uncommon months and years after the injury.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04230-8.

Understanding the Impact of Sex and Gender in Osteoarthritis: Assessing Research Gaps and Unmet Needs

Osteoarthritis (OA) affects more than 300 million individuals globally, with higher prevalence in women than in men. In addition, OA affects women and men differently, with women demonstrating both increased disease severity and disability. The Society for Women's Health Research (SWHR) convened an interdisciplinary group of expert researchers and clinicians for a roundtable meeting to review the current state of the science on OA and to identify knowledge gaps in the scientific literature, especially as they relate to the topics of sex and gender. The current review summarizes discussions from the roundtable and prioritizes areas of need that warrant further attention in OA research, diagnosis, care, and education. Improvements in basic and clinical research, clinical practice, patient education, and policy are needed to allow for better understanding as to the pathogenesis of sex- and gender-related disparities in OA.

Genetic estrogen receptor alpha gene PvuII polymorphism in susceptibility to knee osteoarthritis in a Chinese Han population: A southern Jiangsu study

BACKGROUND

Knee osteoarthritis (KOA) is the most prevalent type of arthritis and genetic factors play an important role in KOA pathogenesis. Some studies have reported the association of estrogen receptor alpha (ESRα) gene polymorphism and KOA susceptibility in different populations. This study was designed to verify whether ESRα gene polymorphism (rs2234693) was associated with primary KOA in a Chinese Han population living in the south of Jiangsu.

METHODS

A case-control association study on single nucleotide polymorphism (SNP) rs2234693 was performed, and a total of 1953 subjects (1033 OA cases and 920 controls) were genotyped. Allele and genotype frequencies were compared between KOA cases and control participants.

RESULTS

SNP rs2234693 was significantly associated with KOA in the dominant genetic model (TT + TC vs. CC) in all the subjects (odds ratio (OR) = 1.30; 95% confidence interval (CI) = 1.02-1.66; P = .03), and T allele frequency was also higher compared with allele C (OR = 1.38; 95% CI = 1.06-1.80; P = .02). After stratification by gender, there was no evident difference between the two groups in female and male subjects (P > .05). With a stratification for KOA severity, the combined genotype (TT + TC) (OR = 1.47; 95% CI = 1.12-1.94; P < .01) and T allele (OR = 1.61; 95% CI = 1.19-2.19; P < .01) were evidently associated with mild KOA, but not with severe KOA.

CONCLUSIONS

ESRα gene is of considerable importance in the pathogenesis of early-stage KOA in a Chinese Han population living in southern Jiangsu.

Association between ADIPOQ gene variants and knee osteoarthritis in a Chinese population

A study from Thailand showed no significant association between the adiponectin (ADIPOQ) gene rs1501299 polymorphism and knee osteoarthritis (OA) risk. To investigate this association in a Chinese population, we conducted this case-control study involving 372 knee OA patients and 453 controls. Genotyping via standard PCR and restriction fragment length polymorphism (PCR-RFLP) showed that TT genotype (TT vs. GG: adjusted odds ratio (OR) (95% confidence interval (CI)) = 1.70 (1.01-2.86)) or T allele (T vs. G: adjusted OR (95% CI) = 1.26 (1.02-1.56)) of ADIPOQ gene rs1501299 polymorphism significantly increased the risk of knee OA. Significant associations were also observed in subgroups ≥55 years (TT vs. GG: adjusted OR (95% CI) = 2.21 (1.00-4.86)) and body mass index (BMI) < 25 kg/m² (TT+GT vs. GG: adjusted OR (95% CI) = 1.53 (1.03-2.29)), but not in the subgroup analysis of sex. In conclusion, the ADIPOQ gene rs1501299 polymorphism intensifies the risk of knee OA in this Chinese Han population. Nevertheless, further studies with larger sample sizes in other populations are warranted to verify this finding.

A hyperactivating proinflammatory RIPK2 allele associated with early-onset osteoarthritis

Osteoarthritis (OA) is a common debilitating disease characterized by abnormal remodeling of the cartilage and bone of the articular joint. Ameliorating therapeutics are lacking due to limited understanding of the molecular pathways affecting disease initiation and progression. Notably, although a link between inflammation and overt OA is well established, the role of inflammation as a driver of disease occurrence is highly disputed. We analyzed a family with dominant inheritance of early-onset OA and found that affected individuals harbored a rare variant allele encoding a significant amino acid change (p.Asn104Asp) in the kinase domain of receptor interacting protein kinase 2 (RIPK2), which transduces signals from activated bacterial peptidoglycan sensors through the NF-κB pathway to generate a proinflammatory immune response. Functional analyses of RIPK2 activity in zebrafish embryos indicated that the variant RIPK2104Asp protein is hyperactive in its signaling capacity, with augmented ability to activate the innate immune response and the NF-κB pathway and to promote upregulation of OA-associated genes. Further we show a second allele of RIPK2 linked to an inflammatory disease associated with arthritis also has enhanced activity stimulating the NF-κB pathway. Our studies reveal for the first time the inflammatory response can function as a gatekeeper risk factor for OA.

Superiority of 2-Level Total Disk Replacement Using a Cervical Disk Prosthesis Versus Anterior Cervical Diskectomy and Fusion

The purpose of this study was to evaluate the superiority of total disk replacement (TDR) using a cervical disk prosthesis vs anterior cervical diskectomy and fusion (ACDF). Ninety-six patients with a diagnosis of degenerative disk disease with radiculopathy or myeloradiculopathy at 2 contiguous levels from C-3 to C-7 were randomly allocated to the TDR group (n=48) or the ACDF group (n=48). Outcome measures were recorded preoperatively and 1 week and 3, 6, 12, 24, and 81 months postoperatively. A total of 80 patients completed the follow-up, including 38 in the TDR group and 42 in the ACDF group. Japanese Orthopaedic Association, visual analog scale, and Neck Disability Index scores showed statistically significant improvement from baseline in both groups. Moreover, compared with the TDR group, the ACDF group had statistically greater visual analog scale scores from 12 months and Neck Disability Index scores from 3 months. Compared with the ACDF group, the TDR group had statistically greater range of motion at both the superior and the inferior treated levels at 3, 6, 12, 24, and 81 months postoperatively. Compared with the TDR group, the ACDF group had statistically greater range of motion at the superior adjacent levels at 6, 12, 24, and 81 months and at the inferior adjacent levels at 24 and 81 months postoperatively. The occurrence of adjacent-segment degeneration at both the superior and the inferior adjacent levels was greater in the ACDF group than in the TDR group. Total disk replacement was safe and effective and a statistically superior alternative to ACDF for degenerative disk disease at 2 contiguous levels. It could reduce the occurrence of adjacent-segment degeneration at the superior and the inferior adjacent segments by reducing the range of motion. [Orthopedics. 2018; 41(6):344-350.].

Prevalence of knee osteoarthritis in former athletes: a systematic review with meta-analysis

BACKGROUND

Prevalence of knee osteoarthritis in former athletes is still unclear.

OBJECTIVE

To investigate prevalence of knee osteoarthritis in former athletes. Moreover, the secondary aim was to investigate whether poor methodological quality of included studies, different diagnosis criteria for knee osteoarthritis, different sports modality or sex impact on overall estimated prevalence of knee osteoarthritis in former athletes.

METHODS

Searches on MEDLINE, EMBASE, AMED, SPORTDiscus and CINAHL from the earliest record to February 2018 and hand-searching identified studies investigating prevalence of knee osteoarthritis in former athletes. Meta-analysis was conducted and the GRADE system summarized strength of the current recommendations. Sensitivity analyses investigated whether methodological quality, diagnostic criteria, type of sports or sex impacted on the overall estimated prevalence in former athletes. This review was registered at PROSPERO (CRD42016050903).

RESULTS

Fifteen studies were included and pooling of 3100 participants estimated overall prevalence of knee osteoarthritis in former athletes of 30.0% (95% CI: 20.0 to 40.0%). The strength of the current recommendations was low-quality. Sensitivity analyses suggested that different diagnostic criteria for knee osteoarthritis and type of sports may impact on the overall estimated prevalence.

CONCLUSIONS

Prevalence of knee osteoarthritis in former athletes was 30.0%. Researchers, clinicians and policymakers should be careful about potential prevalence differences among type of sports and diagnostic criteria. Current low-quality evidence shows that future high-quality studies are likely to impact on the estimated prevalence.

Obesity, osteoarthritis and genetic risk: The rs182052 polymorphism in the ADIPOQ gene is potentially associated with risk of knee osteoarthritis

Objectives

Given the function of adiponectin (ADIPOQ) on the inflammatory condition of obesity and osteoarthritis (OA), we hypothesized that the ADIPOQ gene might be a candidate gene for a marker of susceptibility to OA.

Methods

We systematically screened three tagging polymorphisms (rs182052, rs2082940 and rs6773957) in the ADIPOQ gene, and evaluated the association between the genetic variants and OA risk in a case-controlled study that included 196 OA patients and 442 controls in a northern Chinese population. Genotyping was performed using the Sequenom MassARRAY iPLEX platform.

Results

The single nucleotide polymorphism (SNP) rs182052 was found to be potentially associated with knee OA risk (additive model: odds ratio = 1.38; 95% confidence interval 1.07 to 1.76; p = 0.012). Furthermore, a non-significant association was observed for rs182052 and body mass index with regard to OA risk in interaction analyses (p = 0.063). Similarly, no significant interaction was detected for rs182052 and age with regard to OA risk (p = 0.614).

Conclusion

These findings suggest that the SNP rs182052 in the ADIPOQ gene may potentially modify individual susceptibility to knee OA in the Chinese population. Further studies are warranted to investigate our findings in more depth.

Cite this article: L. Jiang, X. Zhu, J. Rong, B. Xing, S. Wang, A. Liu, M. Chu, G. Huang. Obesity, osteoarthritis and genetic risk: The rs182052 polymorphism in the ADIPOQ gene is potentially associated with risk of knee osteoarthritis. Bone Joint Res 2018;7:494–500. DOI: 10.1302/2046-3758.77.BJR-2017-0274.R1.

FTO variant is not associated with osteoarthritis in the Chinese Han population: replication study for a genome-wide association study identified risk loci

BACKGROUND

Osteoarthritis is the most prevalent form of arthritis worldwide and is the major cause of pain and loss of function in elderly people. A signal of the fat mass and obesity-associated (FTO) gene had been reported in a genome-wide association study of osteoarthritis. The FTO polymorphism (rs8044769) might exert its effect on osteoarthritis through obesity, because it was reported as a body mass index-associated single-nucleotide polymorphism. And replication studies showed inconsistent results for this association. Our present study is to check the association of rs8044769 with osteoarthritis and body mass index in Chinese Han population.

METHODS

A case-control association study was conducted by using 890 osteoarthritis cases and 844 controls in Chinese Han population. rs8044769 was genotyped in all subjects. Allelic and genotypic frequencies were compared between osteoarthritis cases and control subjects. Associations between rs8044769 and body mass index, and body mass index and osteoarthritis were also assessed.

RESULTS

No significant difference was detected in genotype or allele distribution between osteoarthritis cases and controls (P > 0.05). Stratification by gender and body mass index revealed negative association between rs8044769 and osteoarthritis. We did not find any solid association between rs8044769 and higher body mass index. Meanwhile, we demonstrated that higher body mass index (body mass index ≥ 25) was associated with osteoarthritis.

CONCLUSION

Our present study suggested that rs8044769 was not associated with osteoarthritis susceptibility or higher body mass index, and higher body mass index was a risk factor for osteoarthritis in the Chinese Han population. We also proposed that stratification by clinical parameters was crucial to reduce false-positive result in OA association studies.

Association of the resolvin precursor 17-HDHA, but not D- or E- series resolvins, with heat pain sensitivity and osteoarthritis pain in humans

Resolvins are omega-3 fatty acid derived potent bioactive lipids that resolve inflammation and modulate transient receptor potential channels. Exogenous administration of the resolvin precursor 17-HDHA shows a strong analgesic effect in animal models of osteoarthritis and acute inflammatory pain, but has not been studied in humans. Our aim was to assess the role of 17-HDHA and resolvins in heat pain sensitivity and in osteoarthritis pain in humans. Resolvins D1, D2, D3, D5, E1 and 17-HDHA, were measured by liquid chromatography-mass spectrometry and tested for association with heat pain thresholds in 250 healthy volunteers who had undergone quantitative sensory testing. Resolvins D1, D2 and 17-HDHA were then tested in 62 individuals affected with knee osteoarthritis and 52 age matched controls and tested for association with knee pain. Circulating levels of docosahexaenoic acid (DHA) were also measured. Levels of 17-HDHA, but not those of the other 5 resolvins tested, were associated with increased heat pain thresholds (beta = 0.075; 95% CI 0.024, 0.126; p < 0.0046). 17-HDHA was associated with lower pain scores in OA patients (beta −0.41; 95% CI-0.69, −0.12; p < 0.005; adjusted for covariates) but not with radiographic osteoarthritis. The associations of 17-HDHA with heat pain sensitivity and osteoarthritis pain were independent of DHA levels.

The effect of vitamin D supplementation on knee osteoarthritis, the VIDEO study: a randomised controlled trial

OBJECTIVE

Epidemiological data suggest low serum 25-hydroxyvitamin D₃ (25-OH-D₃) levels are associated with radiological progression of knee osteoarthritis (OA). This study aimed to assess whether vitamin D supplementation can slow the rate of progression.

METHOD

A 3-year, double-blind, randomised, placebo-controlled trial of 474 patients aged over 50 with radiographically evident knee OA comparing 800 IU cholecalciferol daily with placebo. Primary outcome was difference in rate of medial joint space narrowing (JSN). Secondary outcomes included lateral JSN, Kellgren & Lawrence grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, stiffness and the Get up and Go test.

RESULTS

Vitamin D supplementation increased 25-OH-D₃ from an average of 20.7 (standard deviation (SD) 8.9) μg/L to 30.4 (SD 7.7) μg/L, compared to 20.7 (SD 8.1) μg/L and 20.3 (SD 8.1) μg/L in the placebo group. There was no significant difference in the rate of JSN over 3 years in the medial compartment of the index knee between the treatment group (average -0.01 mm/year) and placebo group (-0.08 mm/year), average difference 0.08 mm/year (95% confidence interval (CI) [-0.14-0.29], P = 0.49). No significant interaction was found between baseline vitamin D levels and treatment effect. There were no significant differences for any of the secondary outcome measures.

CONCLUSION

Vitamin D supplementation did not slow the rate of JSN or lead to reduced pain, stiffness or functional loss over a 3-year period. On the basis of these findings we consider that vitamin D supplementation has no role in the management of knee OA.

No association of the single nucleotide polymorphism rs8044769 in the fat mass and obesity-associated gene with knee osteoarthritis risk and body mass index: A population-based study in China

OBJECTIVES

Previous genome-wide association studies (GWAS) have reported significant association of the single nucleotide polymorphism (SNP) rs8044769 in the fat mass and obesity-associated gene (FTO) with osteoarthritis (OA) risk in European populations. However, these findings have not been confirmed in Chinese populations.

METHODS

We systematically genotyped rs8044769 and evaluated the association between the genetic variants and OA risk in a case-controlled study including 196 OA cases and 442 controls in a northern Chinese population. Genotyping was performed using the Sequenom MassARRAY iPLEX platform.

RESULTS

We found that the variant T allele of rs8044769 showed no significant association of OA risk (p = 0.791), or association with body mass index (BMI) (pmeta = 0.786) in an additive genetic model. However, we detected a significant interaction between rs8044769 genotypes and BMI on OA risk (p = 0.037), as well as a borderline interaction between rs8044769 genotypes and age on OA risk (p = 0.062).

CONCLUSIONS

Our findings indicate that rs8044769 in the FTO gene may not modify individual susceptibility to OA or increased BMI in the Chinese population. Further studies are warranted to validate and extend our findings.Cite this article: Prof L. Jiang. No association of the single nucleotide polymorphism rs8044769 in the fat mass and obesity-associated gene with knee osteoarthritis risk and body mass index: A population-based study in China. Bone Joint Res 2016;5:169-174. DOI: 10.1302/2046-3758.55.2000589.

A comparison of radiographic anatomic axis knee alignment measurements and cross-sectional associations with knee osteoarthritis

OBJECTIVE

Malalignment is associated with knee osteoarthritis (KOA), however, the optimal anatomic axis (AA) knee alignment measurement on a standard limb radiograph (SLR) is unknown. This study compares one-point (1P) and two-point (2P) AA methods using three knee joint centre locations and examines cross-sectional associations with symptomatic radiographic knee osteoarthritis (SRKOA), radiographic knee osteoarthritis (RKOA) and knee pain.

METHODS

AA alignment was measured six different ways using the KneeMorf software on 1058 SLRs from 584 women in the Chingford Study. Cross-sectional associations with principal outcome SRKOA combined with greatest reproducibility determined the optimal 1P and 2P AA method. Appropriate varus/neutral/valgus alignment categories were established using logistic regression with generalised estimating equation models fitted with restricted cubic spline function.

RESULTS

The tibial plateau centre displayed greatest reproducibility and associations with SRKOA. As mean 1P and 2P values differed by >2°, new alignment categories were generated for 1P: varus <178°, neutral 178-182°, valgus >182° and for 2P methods: varus <180°, neutral 180-185°, valgus >185°. Varus vs neutral alignment was associated with a near 2-fold increase in SRKOA and RKOA, and valgus vs neutral for RKOA using 2P method. Nonsignificant associations were seen for 1P method for SRKOA, RKOA and knee pain.

CONCLUSIONS

AA alignment was associated with SRKOA and the tibial plateau centre had the strongest association. Differences in AA alignment when 1P vs 2P methods were compared indicated bespoke alignment categories were necessary. Further replication and validation with mechanical axis alignment comparison is required.

Strong association of the polymorphisms in PBEF1 and knee OA risk: a two-stage population-based study in China

The association of Pre-B cell colony enhancing factor 1 (PBEF1) with obesity, together with its pro-inflammatory properties suggests that PBEF1 might be another crucial mediator that links inflammation with obesity and primary osteoarthritis (OA). We hypothesized that polymorphisms in PBEF1 may modify the risk of developing OA. Thus we systematically screened 4 tagging polymorphisms (rs4730153, rs2058540, rs3801267 and rs16872158) in PBEF1 and evaluated the association between the genetic variants and OA risk in a two-stage case-control study including 196 cases and 442 controls in the first stage and 143 cases and 238 controls in the second stage. In the first stage, two SNPs (rs4730153 and rs16872158) were found to be potentially associated with OA risk (P < 0.05), which were further confirmed in the second stage with similar effects. After combining the two stages, we found that rs4730153 was significantly associated with decreased risk of OA in an additive genetic model (P < 0.05), while rs16872158 showed increased risk of developing OA (P < 0.05). Combined analysis of these 2 SNPs showed a significant allele-dosage association between the number of risk alleles and OA risk (Ptrend = 5.25 × 10(-5)). These findings indicate that genetic variants in PBEF1 gene may modify individual susceptibility to OA in the Chinese population.

Is the cortical thickness index a valid parameter to assess bone mineral density in geriatric patients with hip fractures?

INTRODUCTION

Reduced bone quality is a common problem during surgical fixation of geriatric hip fractures. The cortical thickness index (CTI) was proposed to assess the bone mineral density (BMD) of the proximal femur on the basis of plain X-rays. The purpose of this study was to evaluate the inter- and intraobserver reliability of the CTI and to investigate correlation between CTI and BMD in geriatric patients.

METHODS

60 patients (20 pertrochanteric fractures, 20 femoral neck fractures, 20 without fractures) were included. All patients had ap and lateral hip X-rays and measurement of BMD by Dual Energy X-ray Absorptiometry at different areas of the hip. The ap and lateral CTI was measured twice by four blinded observers and correlation between mean CTI and BMD was calculated.

RESULTS

Mean ap CTI was 0.52 and mean lateral CTI was 0.45. Inter- and intraobserver reliability was good for ap CTI (ICC 0.71; 0.79) and lateral CTI (ICC 0.65; 0.69). A significant correlation between CTI and overall BMD was found in patients without fractures (r = 0.74; r = 0.67). No significant correlation between CTI and overall BMD was found in patients with proximal femoral fractures.

CONCLUSION

The CTI has sufficient reliability for the use in daily practice. It showed significant correlation with BMD in patients without hip fractures. In patients with proximal femoral fractures, no correlation between CTI and BMD was found. We do not recommend the CTI as parameter to assess the BMD of the proximal femur in geriatric patients with hip fractures.

Association of single nucleotide polymorphisms in estrogen receptor alpha gene with susceptibility to knee osteoarthritis: a case-control study in a Chinese Han population

Osteoarthritis (OA) is the most prevalent form of arthritis and its multifactorial nature has been increasingly recognized. Genetic factors play an important role in OA etiology and estrogen receptor alpha (ESR1) gene polymorphisms may be involved. This study tried to explore whether the ESR1 gene single nucleotide polymorphisms (SNPs) were associated with primary knee OA in the Chinese Han population. Two SNPs, rs2234693 and rs9340799, were genotyped in 469 cases and 522 controls. Rs2234693 was associated with knee OA in the dominant genetic model (TT + TC versus CC) (P = 0.025) and a higher T allele frequency existed (P = 0.047) among females. The combined genotype (TT + TC) (P = 0.025) and T allele (P = 0.016) were related with mild knee OA only. For rs9340799, A allele was associated with knee OA in all subjects (P = 0.031) and females (P = 0.046). Statistical differences were detected in the dominant genetic model (AA + AG versus GG) among females (P = 0.030). The combined genotype (AA + AG) (P = 0.036) and A allele (P = 0.039) were merely correlated with mild knee OA. ESR1 gene is considerably associated with knee OA etiology in the Chinese Han population.

Prevalence of hallux valgus and risk factors among Japanese community dwellers

BACKGROUND

To investigate the prevalence and severity of radiographically detected hallux valgus (HV) as well as associated risk factors among Japanese residents of Miyagawa, a mountain village located in the center of Mie Prefecture.

METHODS

The height, weight and body mass index (BMI) of 403 participants (male n = 135, female n = 268) recruited from among the residents of Miyagawa Village, Japan aged ≥65 years were measured, and baseline data, including age, sex and medical history were obtained from interviews and questionnaires. Knee osteoarthritis (KOA) was determined from radiographs of the feet and knees, and osteoporosis was determined by measuring bone mineral density. Hallux valgus, defined as angulation of the big toe at the first metatarsophalangeal joint of >20°, was classified as: mild (20°-30°), moderate (30°-40°) or severe (>40°). Risk factors for HV were calculated using multivariate logistic regression analysis that included age, sex, obesity (BMI ≥25), KOA, osteoporosis, Heberden's nodes and low back pain as variables.

RESULTS

The overall prevalence of definite radiographic HV was 22.8 % (184/806), and mild, moderate and severe HV was found in 66.3, 27.2 and 6.5 % of the participants, respectively. Hallux valgus was found in at least one foot in 120 (29.8 %) of the participants and the prevalence significantly differed between females with and without HV and KOA (odds ratios: 2.54 and 1.71, respectively).

CONCLUSIONS

The prevalence of definite radiographic HV was 29.8 %. Female sex and KOA were significantly associated with increased risk for radiographic HV.

High prevalence of vitamin D deficiency in elderly patients with advanced osteoarthritis scheduled for total knee replacement associated with poorer preoperative functional state

Vitamin D deficiency has been reported previously in patients with osteoarthritis undergoing total hip arthroplasty. We found a high prevalence of vitamin D deficiency in elderly patients with advanced knee osteoarthritis scheduled for total knee replacement and also a significant association with a lower preoperative functional state. A review of the literature is given on vitamin D deficiency in patients with knee osteoarthritis and the association with lower outcome scores after arthroplasty is discussed.

High prevalence of vitamin D deficiency in elderly patients with advanced osteoarthritis scheduled for total knee replacement associated with poorer preoperative functional state

Vitamin D deficiency has been reported previously in patients with osteoarthritis undergoing total hip arthroplasty. We found a high prevalence of vitamin D deficiency in elderly patients with advanced knee osteoarthritis scheduled for total knee replacement and also a significant association with a lower preoperative functional state. A review of the literature is given on vitamin D deficiency in patients with knee osteoarthritis and the association with lower outcome scores after arthroplasty is discussed.

Genetic epidemiology of osteoarthritis: recent developments and future directions

PURPOSE OF REVIEW

Despite the high prevalence of osteoarthritis and its enormous public health impact, the cause of the disease remains largely obscure. The identification of genes associated with osteoarthritis can help reveal underlying biological mechanisms that may lead to development of new therapeutic targets or biomarkers for early detection and risk stratification. The goal of this short review is to provide a brief overview of the current status of genetics of osteoarthritis with an emphasis on developments generated in the last year.

RECENT FINDINGS

This review focuses on the following areas: identification of new genes through genetic association studies, including genome-wide association studies; family-based studies and extreme osteoarthritis phenotypes; endophenotypes and pain; and overlap of osteoarthritis with other age-related disorders.

SUMMARY

Although recent genetic discoveries have produced innovative findings with respect to the pathophysiology of osteoarthritis, we have yet to realize new treatments to improve the quality of life of patients with osteoarthritis.

Cervical total disc replacement with the Mobi-C cervical artificial disc compared with anterior discectomy and fusion for treatment of 2-level symptomatic degenerative disc disease: a prospective, randomized, controlled multicenter clinical trial: clinical article

OBJECT

Cervical total disc replacement (TDR) is intended to treat neurological symptoms and neck pain associated with degeneration of intervertebral discs in the cervical spine. Anterior cervical discectomy and fusion (ACDF) has been the standard treatment for these indications since the procedure was first developed in the 1950s. While TDR has been shown to be a safe and effective alternative to ACDF for treatment of patients with degenerative disc disease (DDD) at a single level of the cervical spine, few studies have focused on the safety and efficacy of TDR for treatment of 2 levels of the cervical spine. The primary objective of this study was to rigorously compare the Mobi-C cervical artificial disc to ACDF for treatment of cervical DDD at 2 contiguous levels of the cervical spine.

METHODS

This study was a prospective, randomized, US FDA investigational device exemption pivotal trial of the Mobi-C cervical artificial disc conducted at 24 centers in the US. The primary clinical outcome was a composite measure of study success at 24 months. The comparative control treatment was ACDF using allograft bone and an anterior plate. A total of 330 patients were enrolled, randomized, and received study surgery. All patients were diagnosed with intractable symptomatic cervical DDD at 2 contiguous levels of the cervical spine between C-3 and C-7. Patients were randomized in a 2:1 ratio (TDR patients to ACDF patients).

RESULTS

A total of 225 patients received the Mobi-C TDR device and 105 patients received ACDF. At 24 months only 3.0% of patients were lost to follow-up. On average, patients in both groups showed significant improvements in Neck Disability Index (NDI) score, visual analog scale (VAS) neck pain score, and VAS arm pain score from preoperative baseline to each time point. However, the TDR patients experienced significantly greater improvement than ACDF patients in NDI score at all time points and significantly greater improvement in VAS neck pain score at 6 weeks, and at 3, 6, and 12 months postoperatively. On average, patients in the TDR group also maintained preoperative segmental range of motion at both treated segments immediately postoperatively and throughout the study period of 24 months. The reoperation rate was significantly higher in the ACDF group at 11.4% compared with 3.1% for the TDR group. Furthermore, at 24 months TDR demonstrated statistical superiority over ACDF based on overall study success rates.

CONCLUSIONS

The results of this study represent the first available Level I clinical evidence in support of cervical arthroplasty at 2 contiguous levels of the cervical spine using the Mobi-C cervical artificial disc. These results continue to support the use of cervical arthroplasty in general, but specifically demonstrate the advantages of 2-level arthroplasty over 2-level ACDF. Clinical trial registration no.: NCT00389597 (ClinicalTrials.gov).

Diagnosis and clinical presentation of osteoarthritis

Osteoarthritis (OA), the commonest arthropathy, targets the knees, hips, finger interphalangeal joints, thumb bases, first metatarsophalangeal joints, and spinal facet joints, and displays marked heterogeneity of clinical presentation. Signs of OA include coarse crepitus, bony enlargement, reduced range of movement, and joint-line tenderness. Muscle wasting and joint deformity occur with severe OA. Painful periarticular disorders often coexist with OA. Inflammation is absent or only modest, although mild-moderate effusions are common at the knee. The diagnosis of OA may be made without recourse to radiographic or laboratory investigations in the at-risk age group with typical symptoms and signs.

Acetabular fracture: long-term follow-up and factors associated with secondary implantation of total hip arthroplasty

HYPOTHESIS

The present study sought to determine long-term outcome in acetabular fracture and the factors associated with secondary implantation of a total hip arthroplasty and/or with poor functional results.

MATERIAL AND METHODS

Seventy-two patients admitted between 2000 and 2005 were followed up for a maximum 11 years (mean, 6.8 years): 16 females, 56 males; mean age at injury, 41.6 years (median, 40 years). There were 45 simple acetabular fractures, 27 complex fractures and 27 dislocations. Late complications were: osteoarthritis (n=29), osteonecrosis of the femoral head (ONFH: n=8) and heterotopic ossification (n=2).

RESULTS AND DISCUSSION

Twenty-five total hip arthroplasties (THA) were performed, with a mean time to surgery of 3.7 years. Associated factors for THA were: VAS (P<0.0001), PMA (P<0.0001), osteoarthritis (P<0.0001), ONFH (P<0.0002), initial dislocation (P=0.0002), no functional treatment (P=0.0014), surgical treatment (P=0.0065), initial traction (P=0.0068), anterior and posterior congruency defect (P=0.0072 and P<0.0001), and initial intra-articular foreign body (P=0.045). Factors associated with poor or bad functional results were the same, plus: etiology (P=0.0021), BMI (P=0.03) and posterior wall fracture (P=0.0325).

LEVEL OF EVIDENCE

4; retrospective study.

Isolated anterior cruciate ligament reconstruction in patients aged fifty years: comparison of hamstring graft versus bone-patellar tendon-bone graft

PURPOSE

Anterior cruciate ligament (ACL) deficiency contributes to symptomatic functional instability of the knee, regardless of age. We evaluated patient-reported clinical outcome, instrumental stability and prevalence of radiological osteoarthritis based on two homogenous patient samples aged 50 years, an average of three years after isolated ACL reconstruction.

METHODS

ACL reconstruction using a bone-patellar tendon-bone (BPTB) autograft was done in 19 patients and a four-stranded semitendinosus tendon (ST) autograft in 22 patients. Clinical and functional follow-up assessment was performed an average of 32 months after surgical treatment. Clinical and functional follow-up assessment included the International Knee Documentation Committee (IKDC) score, Tegner score and Lysholm score. Instrumental stability testing was carried out using the KT-1000™ arthrometer. The degree of degenerative changes and prevalence of osteoarthritis was based on the Kellgren-Lawrence classification.

RESULTS

Mean follow-up was 32 months (range, 28-36). Mean age was 49.4 years in both groups. The median pre-injury Tegner score was 5.5 (range, 2-8) and the median preoperative Lysholm score was 35 (range, 15-69). At two years, all variables improved significantly for both groups compared to the preoperative values (P < 0.05), with no significant intergroup differences. Approximately 76 % of patients were graded A or B according to the IKDC score in both groups. Activity level according to the scores of Tegner and Lysholm was 4.9/5.3 and 83.4/82.5 on two-year-follow up in both groups. Radiological assessment reported degenerative changes of grade I Osteoarthritis (OA) in 36 % of patients. Grade-II OA was found in 31 % of patients. Grade-III OA and grade-IV OA were found in about 24 % and 7 % of all patients, respectively. Correlation analyses showed significant relationships between conservation of knee-joint stability and clinical outcome according to the IKDC score, and activity level according to the Lysholm score (p < 0.05).

CONCLUSION

Arthroscopic ACL reconstruction using either BPTB graft or hamstring graft in appropriately selected middle-aged patients results in patient satisfaction and good clinical results, with return to a reasonable level of activity regardless of surgical method and graft choice.

Prevalence and influence of tibial tunnel widening after isolated anterior cruciate ligament reconstruction using patella-bone-tendon-bone-graft: long-term follow-up

The aim of the present study was to evaluate incidence, degree and impact of tibial tunnel widening (TW) on patient-reported long-term clinical outcome, knee joint stability and prevalence of osteoarthritis (OA) after isolated anterior cruciate ligament (ACL) reconstruction. On average, 13.5 years after ACL reconstruction via patella-bone-tendon-bone autograft, 73 patients have been re-evaluated. Inclusion criteria consisted of an isolated anterior cruciate ligament rupture and reconstruction, a minimum of 10-year follow-up and no previous anterior cruciate ligament repair or associated intra-articular lesions. Clinical evaluation was performed via the International Knee Documentation Committee (IKDC) score and the Tegner and Lysholm scores. Instrumental anterior laxity testing was carried out with the KT-1000™ arthrometer. The degree of degenerative changes and the prevalence of osteoarthritis were assessed with the Kellgren-Lawrence score. Tibial tunnel enlargement was radiographically evaluated on both antero-posterior and lateral views under establishment of 4 degrees of tibial tunnel widening by measuring the actual tunnel diameters in mm on the sclerotic margins of the inserted tunnels on 3 different points (T1-T3). Afterwards, a conversion of the absolute values in mm into a 4 staged ratio, based on the comparison to the results of the initial drill-width, should provide a better quantification and statistical analysis. Evaluation was performed postoperatively as well as on 2 year follow-up and 13 years after ACL reconstruction. Minimum follow-up was 10 years. 75% of patients were graded A or B according to IKDC score. The mean Lysholm score was 90.2±4.8 (25-100). Radiological assessment on long-term follow-up showed in 45% a grade I, in 24% a grade II, in 17% a grade III and in additional 12% a grade IV enlargement of the tibial tunnel. No evident progression of TW was found in comparison to the 2 year results. Radiological evaluation revealed degenerative changes in sense of a grade II OA in 54% of patients. Prevalence of a grade III or grade IV OA was found in 20%. Correlation analysis showed no significant relationship between the amount of tibial tunnel enlargement (P>0.05), long-term clinical results, anterior joint laxity or prevalence of osteoarthritis. Tunnel widening remains a radiological phenomenon which is most commonly observed within the short to midterm intervals after anterior cruciate ligament reconstruction and subsequently stabilises on mid and long- term follow-up. It does not adversely affect long-term clinical outcome and stability. Furthermore, tunnel widening doesn't constitute an increasing prevalence of osteoarthritis.

Joint-specific twin and familial aggregation of recalled physician diagnosed osteoarthritis

In our three-stage questionnaire study we investigated patterns of twin and familial aggregation of osteoarthritis (OA) for commonly affected joints. The baseline questionnaire study of the Finnish Twin Cohort was performed in 1975. In 1990, 4095 twin pairs of the same gender born 1930–1957 responded to a questionnaire and reported whether they had OA diagnosed by a physician. In 1996 both twins of 266 pairs of which at least one had reported OA in 1990 responded to a detailed questionnaire on joint-specific OA, including family history of OA. In male pairs shared (non-genetic) familial effects accounted for 37% of the total variance in liability to OA and unshared environmental effects for 63%. In female pairs additive gene effects explained 44% of the variance in liability to OA, and unshared environmental effects for 36%. Familial aggregation of finger and knee OA was clearly higher than that of hip OA. Twin-pair discordance for OA was, to some extent, associated with body-mass index, occupational loading and trauma. Our results indicate that genetic effects may be modulated by sex or by environmental factors distributed differently between men and women. Based on our joint-specific data finger and knee joints are the most optimal targets for studies of genetic factors predisposing to the development of OA.

Relationship between insulin-like growth factor-1 and radiographic disease in patients with primary osteoarthritis: a systematic review

OBJECTIVE

To evaluate the association between radiographic osteoarthritis (OA) and either serum insulin-like growth factor-1 (IGF-1) levels or IGF-1 gene polymorphisms in patients with primary OA.

METHODS

We conducted a systematic review of reported associations between circulating IGF-1 and/or IGF-1 gene polymorphisms and radiographic OA. Studies were eligible when: (1) investigating serum IGF-1 and/or IGF-1 gene polymorphisms in relation to prevalent or incident radiographic OA; (2) written in English; (3) full-text article or abstract; (4) patients had primary OA in knee, hip, hand or spine; (5) longitudinal, case-control or cross-sectional design. Quality assessment was done using a standardized criteria set. Best-evidence synthesis was performed based on guidelines on systematic review from the Cochrane Collaboration Back Review Group, using five evidence levels: strong, moderate, limited, conflicting and no evidence.

RESULTS

We included 11 studies with more than 3000 primary OA cases. Data on the relationship between serum IGF-1 and radiographic OA were inconsistent. Adjustment for body mass index (BMI) was often omitted. Of four high-quality studies, three studies reported no association, one study found significantly higher IGF-1 levels in OA patients compared to controls. Patients with IGF-1 gene promoter polymorphisms and a genetic variation at the IGF-1R locus had an increased OA prevalence compared to controls.

CONCLUSIONS

Observational data showed no association between serum IGF-1 and occurrence of radiographic OA (moderate level of evidence), and a positive relationship between IGF-1 gene polymorphisms and radiographic OA (moderate level of evidence); however the confounding effect of BMI was insufficiently addressed. Future well-designed prospective studies should further elaborate the role of the complex GH/IGF-1 system in primary OA.

Brief Fear of Movement Scale for osteoarthritis

OBJECTIVE

Fear of movement has important clinical implications for individuals with osteoarthritis (OA). This study aimed to establish a brief fear of movement scale for use in OA. Items from the Tampa Scale for Kinesiophobia (TSK) were examined.

METHODS

The English version of the TSK was examined in a community-based sample (n = 1,136) of individuals with OA of the hip or knee. Exploratory and confirmatory factor analyses were used to determine the number and content of the dimensions of fear of movement. Factorial invariance was tested across subgroups of sex, race, education, and OA severity. Convergent validity with measures of pain, physical functioning, and psychological functioning was examined.

RESULTS

Factor analyses identified a single-factor 6-item scale that measures activity avoidance due to pain-related fear of movement (confirmatory factor analysis indices of model fit: root mean square error of approximation = 0.04, standardized root mean square residual = 0.01, comparative fit index = 0.99, and Tucker-Lewis Index = 0.99). The 6-item scale demonstrated factorial invariance across sex, race, levels of education, and OA severity, suggesting that this scale performs consistently across diverse groups of individuals with OA. Convergent validity with measures of pain (β = 0.30-0.41), physical functioning (β = 0.44-0.48), and psychological functioning (β = 0.36-0.37) was also demonstrated.

CONCLUSION

The Brief Fear of Movement Scale identified in this study provides a promising and valid approach for assessing fear of movement in individuals with OA. This brief scale demonstrated several important strengths, including a small number of items, sound psychometric properties, and consistent performance across diverse groups of individuals with OA.

Genetic association analysis of GDF5 and ADAM12 for knee osteoarthritis

OBJECTIVES

To examine two single-nucleotide polymorphisms (SNPs) for their association with knee osteoarthritis (OA) susceptibility in Korean cohort.

METHODS

Two thousand four hundred and sixty-two subjects aged 50 years and older were assessed for OA at the knee, were genotyped with two SNPs (GDF5; rs143383 and ADAM12; rs3740199). Radiographs were read by two examiners that used an atlas of radiographic features to obtain a global Kellgren/Lawrence (K/L) score. Genomic DNA was extracted from peripheral blood using a QIAamp DNA Blood Mini Kit. GDF5 genotyping was performed by high resolution melting analysis. ADAM12 genotyping was performed by TaqMan assay. The allele frequencies were assessed by counting alleles. Associations were tested by calculating the odds ratios (ORs) and 95% confidence intervals (95% CIs), using logistic regression analysis with adjustments for age, gender and body mass index (BMI).

RESULTS

Of this cohort, 725 subjects had radiographic OA (defined as a K/L score of ≥ 2). The mean age of the OA patients (females: 76.4%) was 67.4 (7.9) years. In GDF5, we observed a T-allele frequency of 74.1% in our controls, compared with that of 73.7% in patients (P = 0.72; OR 0.97, 95% CI; 0.83-1.13). In ADAM12, the frequency of G-allele in the case (54.6%) versus the control (55.0%) was calculated (P = 0.94, OR 1.01, 95% CI; 0.88-1.15). There was no significant difference in the genotype frequencies between the patients and healthy controls.

CONCLUSION

The associations of two SNPs with OA that were noted in previous studies, were not found in the Korean OA cohort.

Etiology of osteoarthritis: genetics and synovial joint development

Osteoarthritis (OA) has a considerable hereditary component and is considered to be a polygenic disease. Data derived from genetic analyses and genome-wide screening of individuals with this disease have revealed a surprising trend: genes associated with OA tend to be related to the process of synovial joint development. Mutations in these genes might directly cause OA. In addition, they could also determine the age at which OA becomes apparent, the joint sites involved, the severity of the disease and how rapidly it progresses. In this Review, I propose that genetic mutations associated with OA can be placed on a continuum. Early-onset OA is caused by mutations in matrix molecules often associated with chondrodysplasias, whereas less destructive structural abnormalities or mutations confer increased susceptibility to injury or malalignment that can result in middle-age onset. Finally, mutations in molecules that regulate subtle aspects of joint development and structure lead to late-onset OA. In this Review, I discuss the genetics of OA in general, but focus on the potential effect of genetic mutations associated with OA on joint structure, the role of joint structure in the development of OA--using hip abnormalities as a model--and how understanding the etiology of the disease could influence treatment.

Association study of the candidate gene for knee osteoarthritis in Koreans

The aim of this study was to examine a single-nucleotide polymorphism (SNP) rs7639618 of double von Willebrand factor (DVWA) gene for the association with osteoarthritis (OA) susceptibility in Korean cohort. The study was a part of the Korean cohort study. Two thousand four hundred sixty-two subjects aged 50 years and older who were derived from the cohort and who were assessed for OA at the knee were genotyped. The anteroposterior extended-view weight-bearing radiographs of the knees were obtained. Of the subjects, 725 subjects had radiographic OA. Genomic DNA was extracted from peripheral blood using a QIAamp DNA Blood Mini Kit (Qiagen, Valencia, CA). Genotyping was performed using High Resolution Melt or the Taq-Man allelic discrimination assay and the Rotor-Gene 6000 (Corbett Research, Sydney,Australia). Associations were tested by calculating the odds ratios (ORs) and 95% confidence intervals (95% CIs), using logistic regression analysis with adjustments for age, gender, and body mass index (BMI). The mean age of the OA patients (females: 554 subjects, 76.4%) was 67.4 (7.9) years. The intraobserver agreement was high for the identification of osteophytes (κ: 0.80) and joint space narrowing (κ: 0.70). There was no significant difference (all P values > 0.05) in the genotype or allele frequencies between the patients with OA and healthy controls. There was also no significant difference when the cases were adjusted by age, gender, and BMI. The associations of DVWA SNPs with OA were noted in previous studies and were not found in the Korean OA cohort.

A variant in MCF2L is associated with osteoarthritis

Osteoarthritis (OA) is a prevalent, heritable degenerative joint disease with a substantial public health impact. We used a 1000-Genomes-Project-based imputation in a genome-wide association scan for osteoarthritis (3177 OA cases and 4894 controls) to detect a previously unidentified risk locus. We discovered a small disease-associated set of variants on chromosome 13. Through large-scale replication, we establish a robust association with SNPs in MCF2L (rs11842874, combined odds ratio [95% confidence interval] 1.17 [1.11-1.23], p = 2.1 × 10(-8)) across a total of 19,041 OA cases and 24,504 controls of European descent. This risk locus represents the third established signal for OA overall. MCF2L regulates a nerve growth factor (NGF), and treatment with a humanized monoclonal antibody against NGF is associated with reduction in pain and improvement in function for knee OA patients.

Knee function and prevalence of osteoarthritis after isolated anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft: long-term follow-up

PURPOSE

The aim of this investigation was to study patient-reported long-term clinical outcome, instrumental stablitity and prevalence of radiological osteoarthritis (OA) a minimum of ten years after isolated anterior cruciate ligament (ACL) reconstruction.

METHODS

An average of 13.5 years after ACL reconstruction with bone-patellar tendon-bone (BTB) autograft, 73 patients were evaluated. Inclusion criteria consisted of an isolated ACL rupture and reconstruction with BPTB graft with no associated intra-articular lesions, in particular, cartilage alterations or meniscal lesions. Clinical assessment was performed using the International Knee Documentation Committee (IKDC) and Tegner and Lysholm scores. Instrumental anterior laxity testing was carried out with the KT-1000™ arthrometer. Degree of degenerative changes and prevalence of OA were determined using the Kellgren- Lawrence scale.

RESULTS

Mean follow-up was 13.5 years. Mean age was 43.8 years. About 75% of patients were graded A or B according to the IKDC score. The Lysholm score was 90.2 ± 4.8. Radiological assessment reported degenerative changes of grade II OA in 54.2% of patients. Prevalence of grades III or IV OA was found in 20%. The incidence of OA was significantly correlated with stability and function at long-term follow-up.

CONCLUSION

Arthroscopic ACL reconstruction using BPTB autograft resulted in a high degree of patient satisfaction and good clinical results on long-term follow-up. A higher degree of OA developed in 20% of patients and was significantly correlated with increased anterior laxity at long-term follow-up.

Cloning and characterization of the osteoarthritis-associated gene DVWA

Osteoarthritis (OA) is one of the most prevalent skeletal diseases. Recently, we identified a novel gene on chromosome 3p24.3, named DVWA (double von Willebrand factor A domains), and its functional variants, which are associated with susceptibility to knee OA. Here we report the cloning and characterization of the DVWA gene. DVWA consisted of seven exons and had four alternative splicing variants, which encoded long (385 amino acid) and short (276 amino acid) proteins (L-DVWA and S-DVWA, respectively). S-DVWA was an N-terminal truncated form of L-DVWA and lacked a signal peptide and a part of a VWA domain. L-DVWA and S-DVWA transcripts were mainly expressed in articular cartilage. Immunoblot analysis using epitope-tagged proteins showed L-DVWA in the conditioned media and S-DVWA only in the cell, consistent with the in silico prediction. We also cloned the murine counterpart of DVWA, which was found to be identical to Col6a4, which has recently been reported. L-DVWA had 73% identity to the N-terminal sequence of the 2,309-amino acid Col6a4 protein. The mouse Dvwa/Col6a4 mRNA was present mainly in the small intestine in embryos and adults, but not in cartilage. The amino acid sequence of L-DVWA was conserved in higher species than chicken, but that of S-DVWA was unique in human. Knockdown of DVWA by siRNAs increased expression of chondrocyte matrix genes. Our study indicates that DVWA is evolutionally very unique, which, together with its specific expression in articular cartilage, suggests its specific role in human cartilage metabolism.

Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study

Objectives

The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis.

Methods

The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent.

Results

None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects.

Conclusions

Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.

Treatment and Prevention of Osteoarthritis through Exercise and Sports

Osteoarthritis (OA) is a degenerative joint disease with a high prevalence among older people. To date, the pathogenesis of the disease and the link between muscle function and OA is not entirely understood. As there is no known cure for OA, current research focuses on prevention and symptomatic treatment of the disorder. Recent research has indicated that muscle weakness precedes the onset of OA symptoms. Furthermore, several studies show a beneficial effect of land-based aerobic and strengthening exercises on pain relief and joint function. Therefore, current research focuses on the possibility to employ exercise and sports in the prevention and treatment of OA.

Proximal interphalangeal joint arthritis

Proximal interphalangeal joint function is critical for proper finger and hand function and arthritis of this joint can lead to considerable hand impairment. Proximal interphalangeal joint arthritides are broadly categorized into nonerosive and erosive osteoarthritis (OA), posttraumatic arthritis, and inflammatory arthritis. The nonerosive type is considered idiopathic or primary OA, whereas the erosive form exhibits an inflammatory component. Idiopathic or primary OA occurs as a consequence of abnormal mechanical stress that leads to damage of cartilage and subchondral bone, with subsequent cytokine and growth factor activation. Individual genetics then mediate the cellular responses. Although erosive OA is described as a separate entity, this remains controversial, with many suggesting that it is merely a more aggressive form of nonerosive, primary OA. Inflammatory OA occurs when connective tissues are diseased, allowing for normal use to incite arthritic damage. Treatment modalities for proximal interphalangeal joint arthritis are currently limited.

Association of single-nucleotide polymorphisms in HLA class II/III region with knee osteoarthritis

OBJECTIVE

A genome-wide association study and a replication using Japanese, Spanish and Greek Caucasian populations have recently indicated two single-nucleotide polymorphisms (SNPs) (rs7775228 and rs10947262) associated with knee Osteoarthritis (OA) susceptibility. We have further evaluated the association in knee OA subjects from Han Chinese and Australian Caucasian origin.

METHODS

Two independent case-control association studies were performed using Han Chinese and Australian Caucasian populations. The two SNPs were genotyped in patients who had primary symptomatic knee OA with radiographic confirmation and/or received total knee replacement surgery as well as in matched controls. They were subjected to statistic analyses.

RESULTS

A total of 991 OA patients and 1536 controls were genotyped. No significant difference was detected in genotype or allele frequencies of the two SNPs between knee OA and control groups in the two populations (all P>0.05). The association was also negative even after stratification by sex, body mass index (BMI) and Kellgren/Lawrence scores. The significant heterogeneity was detected between Chinese and Japanese (both P<0.05). In the Caucasian samples, no significant heterogeneity was detected (both P>0.05). The result of meta-analysis showed significant association between knee OA and rs10947262 in total subjects [summary OR=1.26, 95%confidence intervals (CI)=1.07-1.27, P=3 × 10(-8)] and in Caucasian samples (summary OR=1.28, 95%CI=1.04-1.57, P=0.02).

CONCLUSION

We demonstrated no association between the two SNPs in human leukocyte antigen (HLA) class II/III region and knee OA in Han Chinese population. A significant association was detected between SNP rs10947262 and knee OA in Caucasian subjects. Further replication studies are required to identify the impact of controversial association.

Heritability patterns in hand osteoarthritis: the role of osteophytes

INTRODUCTION

The objective of the present study was to assess heritability of clinical and radiographic features of hand osteoarthritis (OA) in affected patients and their siblings.

METHODS

A convenience sample of patients with clinical and radiographic hand OA and their siblings were evaluated by examination and radiography. Radiographs were scored for hand OA features by radiographic atlas. The heritability of hand OA phenotypes was assessed for clinical and radiographic measures based on anatomic locations and radiographic characteristics. Phenotypic data were transformed to reduce non-normality, if necessary. A variance components approach was used to calculate heritability.

RESULTS

One hundred and thirty-six probands with hand OA and their sibling(s) were enrolled. By anatomic location, the highest heritability was seen with involvement of the first interphalangeal joint (h2 = 0.63, P = 0.00004), the first carpometacarpal joint (h2 = 0.38, P = 0.01), the distal interphalangeal joints (h2 = 0.36, P = 0.02), and the proximal interphalangeal joints (h2 = 0.30, P = 0.03) with osteophytes. The number and severity of joints with osteophyte involvement was heritable overall (h2 = 0.38, P = 0.008 for number and h2 = 0.35, P = 0.01 for severity) and for all interphalangeal joints (h2 = 0.42, P = 0.004 and h2 = 0.33, P = 0.02). The severity of carpometacarpal joint involvement was also heritable (h2 = 0.53, P = 0.0006). Similar results were obtained when the analysis was limited to the Caucasian sample.

CONCLUSIONS

In a population with clinical and radiographic hand OA and their siblings, the presence of osteophytes was the most sensitive biomarker for hand OA heritability. Significant heritability was detected for anatomic phenotypes by joint location, severity of joint involvement with osteophytes as well as for overall number and degree of hand OA involvement. These findings are in agreement with the strong genetic predisposition for hand OA reported by others. The results support phenotyping based on severity of osteophytes and a joint-specific approach. More specific phenotypes may hold greater promise in the study of genetics in hand OA.

Genetic polymorphism of PITX1 in susceptibility to knee osteoarthritis in a Chinese Han population: a case-control study

Osteoarthritis (OA) is the most common form of arthritis and the precise etiology of this disease remains unclear. Genetic factors play a considerable role in pathogenesis of OA. Several OA-susceptibility genes have been identified. Recently, a new emerging role of pitx1 transcription factor in OA pathogenesis has been reported. Paired-like homeodomain transcription factor 1 (PITX1) has been implicated in hind limb development of mice and is essential to maintain cartilage function. Because of the different expression in the knee joint between OA and normal people, PITX1 may be involved in etiology and pathogenesis of OA. The present study is to evaluate the association of the PITX1 polymorphism (rs479632) with knee OA in a Chinese Han population. A case-control association study was conducted. The polymorphism was genotyped in 581 patients who had primary symptomatic knee OA with radiographic confirmation and in 570 matched controls. Allelic and genotypic frequencies were compared between patients and control subjects. No significant difference was detected in genotype or allele distribution between knee OA and control groups (all P > 0.05). The association was also negative even after stratification by sex. Furthermore, no association between the SNP genotype and the clinical variables age, sex, body mass index (BMI), and Kellgren/Lawrence (K/L) score was observed in OA patients. The present study suggests that the PITX1 polymorphism (rs479632) is not a risk factor for knee OA susceptibility in the Chinese Han population. Further studies are needed to give a global view of this polymorphism in pathogenesis of OA.

The relationship of estrogen receptor-alpha and -beta genes with osteoarthritis of the hand

OBJECTIVE

We examined reported associations between radiographic hand osteoarthritis (OA) and single-nucleotide polymorphisms (SNP) in 2 candidate genes associated with OA in other joints: estrogen receptor alpha (ESR1) and beta (ESR2).

METHODS

In 539 Framingham Offspring Study participants (49% men; mean age 61 +/- 9 yrs) joint-specific radiographic hand OA was defined as Kellgren/Lawrence (K/L) scores >or= 2 in the first carpometacarpal joint (CMC), distal interphalangeal joints (DIP), first-digit interphalangeal joint (IP), or proximal interphalangeal joints (PIP). Four SNP were genotyped for ESR1 (PvuII-rs2234693, XbaI-rs9340799, rs2077647, and rs1801132) and 4 for ESR2 (rs1256031, rs1256034, rs1256059, rs944460). Logistic regression analyses were performed to evaluate the relationships between genotypes and hand OA, adjusting for age, sex, height, and weight.

RESULTS

Radiographic hand OA was identified in at least one investigated joint of DIP (39%), PIP (33%), and first CMC (40%). There was no evidence of association between OA and genotype at any polymorphism. We found no significant association between our OA phenotypes or generalized or severe generalized OA as defined by Ushiyama and heterozygosity for rs2234693 and rs9340799, although in metaanalysis with the former study this heterozygosity remained significantly associated with generalized or severe generalized OA.

CONCLUSION

We found no significant association between hand OA and the investigated polymorphisms of ESR1 or ESR2 despite published reports of association and a priori hypotheses implicating their potential roles. However, we could not absolutely exclude associations with rs2234693, rs9340799, or rs944460.

Pretreatment insulin-like growth factor-I concentrations predict radiographic osteoarthritis in acromegalic patients with long-term cured disease

OBJECTIVE

The aim of the study was to identify factors influencing the development of osteoarthritis during long-term control of acromegaly, focusing on disease-specific parameters, GH and IGF-I concentrations, and duration of disease, adjusted for the well-known determinants of primary osteoarthritis.

DESIGN

We conducted a follow-up study.

METHODS

We studied 67 patients with adequate biochemical control of acromegaly for a mean of almost 13 yr. Study parameters were the results of radiological assessment of the spine, hip, knee, and hand. Osteoarthritis was defined as radiological osteoarthritis using the scoring system developed by Kellgren and Lawrence. Correlations between potential factors of influence and osteoarthritis were performed by analysis of covariance and adjusted for age, gender, and body mass index.

RESULTS

Patients with pretreatment IGF-I sd scores in the highest tertile had an almost 4-fold increased risk for radiological osteoarthritis of the hip when compared with patients in the lowest tertile. After adjustment for age, gender, BMI, and disease duration, pretreatment IGF-I sd scores predicted radiographic osteoarthritis in all joint sites. Osteoarthritis was not predicted by other factors, including pretreatment GH levels, type of treatment, and duration of follow-up.

CONCLUSION

This is the first study to document pretreatment IGF-I concentration as a predictor of radiographic osteoarthritis in acromegalic patients with long-term disease control.

Developments in the scientific understanding of osteoarthritis

Osteoarthritis is often a progressive and disabling disease, which occurs in the setting of a variety of risk factors--such as advancing age, obesity, and trauma--that conspire to incite a cascade of pathophysiologic events within joint tissues. An important emerging theme in osteoarthritis is a broadening of focus from a disease of cartilage to one of the 'whole joint'. The synovium, bone, and cartilage are each involved in pathologic processes that lead to progressive joint degeneration. Additional themes that have emerged over the past decade are novel mechanisms of cartilage degradation and repair, the relationship between biomechanics and biochemical pathways, the importance of inflammation, and the role played by genetics. In this review we summarize current scientific understanding of osteoarthritis and examine the pathobiologic mechanisms that contribute to progressive disease.