Gender difference in symptomatic radiographic knee osteoarthritis in the Knee Clinical Assessment--CAS(K): a prospective study in the general population

Adult Stem Cells for Cartilage Regeneration

As cartilage is an avascular, aneural structure, it has very low capabilities of self-repair. Osteoarthritis prevalence is increasing, and there are no clinically approved management techniques that can cure the degradation of cartilage. This report investigates the efficacy of different sources of cells to generate articular cartilage. Autologous chondrocyte implantation has been used to some extent in clinics; however it has not generated efficient, reliable results, and there is no evidence of long-term success. The usage of stem cells is more promising, particularly mesenchymal stem cells (MSCs). Human embryonic stem cells (hESCs) have also been trialed; however, it is important to note that the process of differentiation into chondrocytes is not fully understood, and the cartilage produced can often be of poor quality. MSCs seems to be the way forward, and hESCs will perhaps need further study with the usage of MSC differentiation methodology.

Bony asymmetry in patellofemoral morphology and risk factors of instability are mostly clinically negligible

PURPOSE

Previous investigations suggested that femoral side-to-side differences were located in the upper femur anatomy. However, little is known about the asymmetry between distal femur and patella. The degree of bony asymmetry in the patellofemoral joint was evaluated using pairs of CT-scans with emphasis on morphometric measurements and risk factors relevant to patellofemoral disorders.

METHODS

Patellofemoral morphometric parameters and anatomical risk factors were analyzed from 345 pairs of CT scans to evaluate side-to-side differences for each patient. All measurements were automatized using previously published algorithm-calculated bone landmarks. We analyzed asymmetry based on absolute differences (AD) and percentage asymmetry (AS%). Significant asymmetry was defined as AS% > 10%.

RESULTS

Patellar height was found to be highly symmetric (mean AD 0.1 for both Insall-Salvatti and Caton-Deschamps methods, AS% 8% and 9%, respectively). Patellar and femoral morphometric parameters were found highly symmetric, except for the trochlear groove depth. Substantial asymmetry was reported in two patellofemoral risk factors: the lateral trochlear inclination (mean AD 2°, AS% 16%) and the tibial tuberosity-trochlear groove distance (1 mm, 116%). Patellar and femoral morphometric asymmetries were independent of demographics, including age, gender, height, weight and ethnicity.

CONCLUSION

Patellar height was found to be highly symmetric and is, therefore, a reasonable index for contralateral templating. While very few patellofemoral morphometric parameters and anatomical risk factors were asymmetric, the mean differences were clinically negligible and independent of demographics.

LEVEL OF EVIDENCE

III.

The compartmental distribution of knee osteoarthritis - a systematic review and meta-analysis

OBJECTIVES

For a population with knee osteoarthritis (OA), determine: 1) the prevalence of single compartmental, bicompartmental and tricompartmental OA, 2) the prevalence of isolated medial tibiofemoral, lateral tibiofemoral, or patellofemoral OA, and combinations thereof.

METHODS

PubMed and Web of Science databases, and reference lists of identified studies, were searched to find studies which reported on the compartmental distribution and prevalence of knee OA. Two independent reviewers assessed studies against pre-defined inclusion criteria and prevalence data were extracted along with subject characteristics. The methodological quality of each included study was assessed. A random-effects model meta-analysis was performed for each OA category to estimate the relative prevalence of OA in the knee compartments amongst people with knee OA.

RESULTS

16 studies (3,786 knees) met the inclusion criteria. High heterogeneity was measured. Normalised for knees with OA, estimated prevalence rates (95% CI) were: single compartmental 50% (31.5-58.3%), bicompartmental 33% (23.1-37.2%) and tricompartmental only 17% (8.8-24.8%). Isolated medial tibiofemoral OA, isolated patellofemoral OA, and combined medial tibiofemoral and patellofemoral OA were more common than tricompartmental disease, occurring in 27% (15.2-31.1%), 18% (9.9-22.7%) and 23% (14.1-27.3%) of people respectively. Single/bicompartmental patterns of disease involving the lateral tibiofemoral compartment were less common, summing to 15% (8.5-18.7%).

CONCLUSION

Three-quarters of people with knee OA do not have tricompartmental disease. This is not reflected in the frequency with which partial and combined partial knee arthroplasties are currently used.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42019140345).

Examining the Association of Knee Pain with Modifiable Cardiometabolic Risk Factors

OBJECTIVE

There is a well-established link between obesity and knee osteoarthritis, and recent research has implicated diabetes as a potential cause of cartilage degeneration. This study uses the National Health and Nutrition Examination Survey (NHANES) database to examine the association between knee pain and various metabolic factors.

METHODS

A retrospective cross-sectional study of the NHANES database from 1999 to 2004 was performed. The main outcome was any knee pain and bilateral knee pain. Main effects of interest were body mass index (BMI), and hemoglobin A1c (HbA1c). We additionally assessed various patient factors including age, race, poverty, gender and smoking status. Multivariable logistic regression models and interaction terms were analyzed.

RESULTS

Data on 12,900 patients was included. In the main adjusted analysis, the modifiable risk factors associated with any knee pain were: overweight (OR 0.91; 95% CI 0.85, 0.97), obesity (OR 1.54; 95% CI 1.42, 1.66), glycemic control (OR 1.20; 95% CI 1.03, 1.38), and current smokers (OR 1.15; 95% CI 1.05, 1.27), all p<0.05. These same factors remain significant for bilateral knee pain. Subgroup analysis showed patients under 65 years old have a 5% increase in risk of any knee pain as their body mass index increases, but patients 65 years and older have a 10% increase in risk.

CONCLUSION

This study confirms the association of knee pain with increased weight, glycemic control, current smoking and age. Most of these risk factors can be modified in patients with knee pain and should be discussed when providing conservative treatment options.

Pain and knee damage in male and female mice in the medial meniscal transection-induced osteoarthritis

OBJECTIVE

To investigate sex effects on pain-related behaviors in the medial meniscal transection (MMT) knee osteoarthritis (OA) model.

METHODS

Experiments were performed in male and female C57BL/6J mice (12/group/sex). MMT was induced by transection of the medial collateral ligament and the medial meniscus. Sham-operated and naïve mice served as controls. Mechanical and heat sensitivity in hind paws, hind limb use, and locomotor activity were measured for 3 months. Knee histology was performed on week 12.

RESULTS

In males, MMT triggered a bi-phasic mechanical hypersensitivity and decreased load on OA limb, with an acute post-operative (1-5 days) and chronic (3-12 weeks) OA phases separated by a remission in the intermediate phase (1-2 weeks). Females showed a less pronounced bi-phasic pattern, with a greater mechanical hypersensitivity, but not poorer limb use, than males in the intermediate phase (maximal difference: 1.1 g, 95% confidence intervals (CI) [0.7, 1.5]). There were no major sex differences in the chronic phase. MMT did not induce heat hypersensitivity or change in locomotor activity in the chronic phase in both sexes. MMT caused more severe cartilage damage in males than in females (maximal difference: 1.1 score points, 95% CI [1.9, 0.3]), and a comparable between sexes osteophyte formation. The knee damage did not correlate with pain.

CONCLUSIONS

MMT modelled human knee OA well, capturing cartilage destruction and osteophyte formation, mechanical pain, and poorer limb use in both sexes. Sex differences in pain were modality- and time-dependent, reflecting complex sex-related features of human OA.

Epidemiology of knee osteoarthritis using Kellgren and Lawrence scale in Indian population

INTRODUCTION

Osteoarthritis knee is one of the most prevalent conditions of knee in elder age group of population. Its causes pain, disability in geriatric population of society. Longer life expectancy is responsible for increase in osteoarthritis knee. K-L scale is well known scale of radiographic OA knee. This study was done to find prevalence of OA knee in Indian population of older than 40 years using K-L scale.

METHOD

The study was a community based cross sectional study. The target population was from 5 metropolis, 5 cities near the metropolis, 5 towns and 20 villages from blocks of these towns. i.e. 5 sample groups were covered. Sample size n = 4680 which was further divided into 5 sites equally (936 from each site). This was rounded to a sample of 1000 from each site. This evaluation study was conducted using the household as the primary sampling unit for the quantitative survey. The respondents for the study were above 40 years. Quantitative data was collected using structured questionnaire and X-Ray Investigation. OA was graded using the Kellgren and Lawrence scale. Data analysis was performed using SPSS statistical software. Frequencies and percentages were calculated to find the prevalence of OA. Chi-Square test was used to find the association of OA with various factors.

RESULTS

The present study shows a prevalence of 28.7% of OA in the overall sample. This varies slightly in the individual states - Agra (35.5%), Bangalore (26.6%), Kolkata (33.7%), Dehradun (27.2%), and Pune (21.7%).OA prevalence was found to be more in participants who used western toilet (42.1%), in sedentary people (82.9%), in females and in obese.

CONCLUSION

This study has evidenced that there is a large percentage of sub-threshold population. i.e. K-L grade 1 which is considered as border-line or doubt-full as far as OA diagnosis. Awareness of OA should be initiated at community level, which is needed for prevention of OA at early age.

Low skeletal muscle mass and radiographic osteoarthritis in knee, hip, and lumbar spine: a cross-sectional study

BACKGROUND

Although several studies have shown that low skeletal muscle mass is correlated with knee osteoarthritis, no studies have investigated the correlation between skeletal muscle mass and hip and lumbar spine osteoarthritis (OA).

AIM

This study aimed to delineate the relationship between low skeletal muscle mass and radiographic OA (ROA) of the knee, hip, and lumbar spine.

METHODS

This is a cross-sectional study using the public data obtained from the Fifth Korean National Health and Nutrition Examination Survey (2010-2011). We included subjects aged ≥ 50 years who completed the surveys (3813 subjects). ROA was assessed by knee, hip, and lumbar spine radiographs and defined as Kellgren/Lawrence (KL) grade of at least 2 in the knee and lumbar spine, whereas KL grade ≥ 1 in the hip. Multivariate logistic regression analyses were performed to evaluate the effects of low skeletal muscle mass on radiographic joint degeneration.

RESULTS

Appendicular skeletal muscle mass (ASM) was higher in subjects with healthy joints than in subjects with knee and lumbar spine ROA (18.9 ± 0.1 kg vs. 17.1 ± 0.2 kg, P < 0.0001 and 18.6 ± 0.1 kg vs. 17.4 ± 0.2 kg, P < 0.0001, respectively), whereas it was higher in those with ROA than in those with healthy hip (17.9 ± 0.1 kg vs. 19.1 ± 0.2 kg P < 0.0001). On multivariate logistic regression analysis, lower skeletal muscle mass independently associated with knee ROA [odds ratio (OR) 1.348; 95% confidence interval (CI) 1.037-1.752]. However, it was inversely associated with lumbar spine ROA (OR 0.786; 95% CI 0.623-0.991).

CONCLUSION

Low skeletal muscle mass was independently associated with knee ROA alone, whereas it was inversely associated with lumbar spine ROA. These opposite results might originate from measuring the area of ASM.

Clinical Significance of Medial Versus Lateral Compartment Patellofemoral Osteoarthritis: Cross-Sectional Analyses in an Adult Population With Knee Pain

OBJECTIVE

To determine the comparative prevalence, associations with selected patient characteristics, and clinical outcomes of medial and lateral compartment patellofemoral (PF) joint osteoarthritis (OA).

METHODS

Information was collected by questionnaires, clinical assessment, and radiographs from 745 eligible community-dwelling symptomatic adults age ≥50 years. PF joint space narrowing (JSN) and osteophytes were scored from skyline radiographs using the Osteoarthritis Research Society International atlas. Multilevel models were used to assess associations of compartmental PF joint OA with age, sex, body mass index (BMI) and varus-valgus malalignment, while median regression was used to examine associations with clinical outcomes (current pain intensity on a numeric rating scale [0-10] and the function subscale of the Western Ontario and McMaster Universities Osteoarthritis Index [0-68]).

RESULTS

Isolated lateral PF joint OA was more common than isolated medial PF joint OA, particularly at higher severity thresholds. Irrespective of severity threshold, age (≥2 odds ratio [OR] 1.19 [95% confidence interval (95% CI) 1.12, 1.26]), BMI (≥2 OR 1.15 [95% CI 1.07, 1.24]), and valgus malalignment (≥2 OR 2.58 [95% CI 1.09, 6.07]) were associated with increased odds of isolated lateral JSN, but isolated medial JSN was only associated with age (≥2 OR 1.20 [95% CI 1.14, 1.27]). The pattern of association was less clear for PF joint osteophytes. Isolated lateral PF joint OA, defined by JSN or osteophytes, was associated with higher pain scores than isolated medial PF joint OA, but these differences were modest and were not significant. A similar pattern of association was seen for functional limitation but only when PF joint OA was defined by JSN.

CONCLUSION

Isolated lateral PF joint OA is more common than isolated medial PF joint OA, and it is more consistently associated with established OA risk factors. It is also associated with higher, but clinically nonsignificant, pain and function scores than isolated medial PF joint OA, particularly when PF joint OA is defined using JSN.

The prevalence of radiographic and MRI-defined patellofemoral osteoarthritis and structural pathology: a systematic review and meta-analysis

BACKGROUND

Patellofemoral osteoarthritis (PF OA) is more prevalent than previously thought and contributes to patient's suffering from knee OA. Synthesis of prevalence data can provide estimates of the burden of PF OA.

OBJECTIVE

This study aims to conduct a systematic review and meta-analysis on the prevalence of PF OA and structural damage based on radiography and MRI studies in different populations.

METHODS

We searched six electronic databases and reference lists of relevant cross-sectional and observational studies reporting the prevalence of PF OA. Two independent reviewers appraised methodological quality. Where possible, data were pooled using the following categories: radiography and MRI studies.

RESULTS

Eighty-five studies that reported the prevalence of patellofemoral OA and structural damage were included in this systematic review. Meta-analysis revealed a high prevalence of radiographic PF OA in knee pain or symptomatic knee OA (43%), radiographic knee OA or at risk of developing OA (48%) and radiographic and symptomatic knee OA (57%) cohorts. The MRI-defined structural PF damage in knee pain or symptomatic population was 32% and 52% based on bone marrow lesion and cartilage defect, respectively.

CONCLUSION

One half of people with knee pain or radiographic OA have patellofemoral involvement. Prevalence of MRI findings was high in symptomatic and asymptomatic population. These pooled data and the variability found can provide evidence for future research addressing risk factors and treatments for PF OA.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42016035649).

Characterisation of a divergent progenitor cell sub-populations in human osteoarthritic cartilage: the role of telomere erosion and replicative senescence

In recent years it has become increasingly clear that articular cartilage harbours a viable pool of progenitor cells and interest has focussed on their role during development and disease. Analysis of progenitor numbers using fluorescence-activated sorting techniques has resulted in wide-ranging estimates, which may be the result of context-dependent expression of cell surface markers. We have used a colony-forming assay to reliably determine chondroprogenitor numbers in normal and osteoarthritic cartilage where we observed a 2-fold increase in diseased tissue (P  < 0.0001). Intriguingly, cell kinetic analysis of clonal isolates derived from single and multiple donors of osteoarthritic cartilage revealed the presence of a divergent progenitor subpopulation characterised by an early senescent phenotype. Divergent sub-populations displayed increased senescence-associated β–galactosidase activity, lower average telomere lengths but retained the capacity to undergo multi-lineage differentiation. Osteoarthritis is an age-related disease and cellular senescence is predicted to be a significant component of the pathological process. This study shows that although early senescence is an inherent property of a subset of activated progenitors, there is also a pool of progenitors with extended viability and regenerative potential residing within osteoarthritic cartilage.

Adipose, Bone Marrow and Synovial Joint-Derived Mesenchymal Stem Cells for Cartilage Repair

Current cell-based repair strategies have proven unsuccessful for treating cartilage defects and osteoarthritic lesions, consequently advances in innovative therapeutics are required and mesenchymal stem cell-based (MSC) therapies are an expanding area of investigation. MSCs are capable of differentiating into multiple cell lineages and exerting paracrine effects. Due to their easy isolation, expansion, and low immunogenicity, MSCs are an attractive option for regenerative medicine for joint repair. Recent studies have identified several MSC tissue reservoirs including in adipose tissue, bone marrow, cartilage, periosteum, and muscle. MSCs isolated from these discrete tissue niches exhibit distinct biological activities, and have enhanced regenerative potentials for different tissue types. Each MSC type has advantages and disadvantages for cartilage repair and their use in a clinical setting is a balance between expediency and effectiveness. In this review we explore the challenges associated with cartilage repair and regeneration using MSC-based cell therapies and provide an overview of phenotype, biological activities, and functional properties for each MSC population. This paper also specifically explores the therapeutic potential of each type of MSC, particularly focusing on which cells are capable of producing stratified hyaline-like articular cartilage regeneration. Finally we highlight areas for future investigation. Given that patients present with a variety of problems it is unlikely that cartilage regeneration will be a simple "one size fits all," but more likely an array of solutions that need to be applied systematically to achieve regeneration of a biomechanically competent repair tissue.

Does a new implant design with more physiological kinematics provide better results after knee arthroplasty?

BACKGROUND

Improved knee kinematics is one of the major goals to obtain better satisfaction after total knee arthroplasty. This study examined whether a guided motion knee design improves functional outcome and satisfaction as compared to a conventional design.

METHODS

In a retrospective manner, from January 2005 to December 2008, patients with two different kinematic TKA designs were enrolled. The 150 patients were divided into two groups: guided motion group (77) with kinematic design (Journey) and control group (73) with no kinematic design (LCS). All the patients had the same surgical technique and postoperative protocols. The functional and radiographic results were interpreted with the Hospital for Special Surgery (HSS) knee score and WOMAC score.

RESULTS

After a mean follow-up of 84.2months, the guided motion group had higher mean postoperative range of motion (p=0.022), functional status in the WOMAC function subscale (p=0.002), but had higher residual pain in the WOMAC pain subscale (p=0.018 and p=0.013) and higher iliotibial band syndrome incidence (6.6% vs 0%; p=0.02). There were no significant differences in HSS score between the two groups. No differences were seen between groups in patient satisfaction in the WOMAC total score (p=0.46) and survival rate.

CONCLUSION

The guided motion design can improve functional status according to WOMAC but not to HSS knee scores. Poorer pain scores and no higher patient satisfaction were observed with this kinematic design.

Annual consultation incidence of osteoarthritis estimated from population-based health care data in England

OBJECTIVES

To estimate the consultation incidence of OA using population-based health care data in England and compare OA incidence figures with those derived in other countries.

METHODS

A population-based health care database (Consultations in Primary Care Archive) in England was used to derive the consultation incidence of OA (overall and by joint site) using the maximum available run-in period method. These estimates, and their distribution by age and sex, were compared with those published from population-based health care databases in Canada, the Netherlands and Spain. A novel age-stratified run-in period method was then used to investigate whether the consultation incidence has been increasing over time in younger adults.

RESULTS

The annual consultation incidence of OA (any joint) was 8.6/1000 persons ≥15 years of age (95% CI 7.9, 9.3) [6.3 (95% CI 5.5, 7.1) in men and 10.8 (95% CI 9.8, 12.0) in women]. Incidence increased sharply between 45 and 64 years of age, peaking at 75-84 years. The joint-specific incidence was 1.4 (95% CI 1.1, 1.7), 3.5 (95% CI 3.1, 3.9) and 1.3 (95% CI 1.1, 1.6) for hip OA, knee OA and hand OA, respectively. The estimates and their distribution by age and sex were broadly consistent with international estimates. Between 2003 and 2010, incidence in those aged 35-44 years increased from 0.3 to 2.0/1000 persons.

CONCLUSION

Newly diagnosed cases of OA in England occur in 9 in 1000 at-risk adults each year, similar to other international estimates. Although lower, the consultation incidence proportion in younger adults appears to have increased in the past decade.

Potential role of age, sex, body mass index and pain to identify patients with knee osteoarthritis

AIM

To evaluate the potential role of age, sex, body mass index (BMI), radiographic features and pain in knee osteoarthritis (OA) case ascertainment.

METHODS

A cross-sectional study was performed using information from the EPIPorto cohort; social, demographic, behavioral and clinical data was obtained. Pain was assessed using a pain frequency score (regarding ever having knee pain, pain in the last year, in the last 6 months and in the last month). Knee radiographs were classified using the Kellgren-Lawrence scale (0-4). Path analysis was used to assess the plausibility of the causal assumptions and a classification tree to identify characteristics that could improve the identification of patients with radiographic OA.

RESULTS

Higher age and higher BMI were associated with higher radiographic score, but sex had no statistical association. Females, higher age, higher BMI and higher radiographic score were statistically associated with higher pain scores. For both genders, the classification tree estimated age as the first variable to identify individuals with knee radiographic features. In females older than 56 years, pain frequency score is the second discriminator characteristic, followed by age (> 65 years) and (BMI > 30 kg/m² ). Higher pain frequency and BMI > 29 kg/m² were relevant for identifying OA in men with ages between 43.5 and 55.5 years.

CONCLUSIONS

Age, BMI and pain frequency are independently associated with radiographic OA and the use of information on these characteristics can improve the identification of patients with knee OA. Beyond age, pain complaints are particularly relevant but the level of pain is different by sex.

Patient preference and willingness to pay for knee osteoarthritis treatments

PURPOSE

To review treatments for osteoarthritis of the knee (OAK) received by patients across five European countries, and to obtain patients' perceptions and willingness to pay for current treatments.

PATIENTS AND METHODS

A prospective, internet-based, double-blind survey of adults with OAK was conducted in France, Germany, Italy, Spain, and the United Kingdom. The questionnaire included questions about diagnosis, treatment history, and perceptions of OAK treatments, followed by a discrete choice-based conjoint exercise to identify preferred attributes of OAK treatments, evaluating 14 sets of four unbranded products.

RESULTS

Two thousand and seventy-three patients with self-reported OAK completed the survey; 17.4% of patients rated their knee pain as drastically affecting their ability to perform normal daily activities, and 39.3% of employed patients reported that they had lost work time because of OAK. The most common treatments were exercise (69.7%), physical therapy (68.2%), and nonprescription oral pain medication (73.9%). Treatments perceived as most effective were: viscosupplement injections (74.1%), narcotics (67.8%), and steroid injection (67.6%). Patient co-pay, duration of pain relief, and type of therapy exhibited the largest impact on patient preference for OAK treatments. The average patient was willing to pay €35 and €64 more in co-pay for steroid and viscosupplement injections, respectively, over the cost of oral over-the-counter painkillers (per treatment course, per knee) (each P<0.05).

CONCLUSION

OAK is a debilitating condition that affects normal daily activities. In general, treatments most commonly offered to patients are not those perceived as being the most effective. Patients are willing to pay a premium for treatments that they perceive as being more effective and result in longer-lasting pain relief, and those that can be administered with fewer visits to a physician.

Examining sex differences in knee pain: the multicenter osteoarthritis study

OBJECTIVE

To determine whether women experience greater knee pain severity than men at equivalent levels of radiographic knee osteoarthritis (OA).

DESIGN AND METHODS

A cross-sectional analysis of 2712 individuals (60% women) without knee replacement or a recent steroid injection. Sex differences in pain severity at each Kellgren-Lawrence (KL) grade were assessed by knee using visual analog scale (VAS) scale and Western Ontario and McMaster Universities Arthritis Index (WOMAC) with and without adjustment for age, analgesic use, Body mass index (BMI), clinic site, comorbid conditions, depression score, education, race, and widespread pain (WSP) using generalized estimating equations. Effect sizes (Cohen's d) were also calculated. Analyses were repeated in those with and without patellofemoral OA (PFOA).

RESULTS

Women reported higher VAS pain at all KL grades in unadjusted analyses (d = 0.21-0.31, P < 0.0001-0.0038) and in analyses adjusted for all covariates except WSP (d = 0.16-0.22, P < 0.0001-0.0472). Pain severity differences further decreased with adjustment for WSP (d = 0.10-0.18) and were significant for KL grade ≤2 (P = 0.0015) and 2 (P = 0.0200). Presence compared with absence of WSP was associated with significantly greater knee pain at all KL grades (d = 0.32-0.52, P < 0.0001-0.0008). In knees with PFOA, VAS pain severity sex differences were greater at each KL grade (d = 0.45-0.62, P = 0.0006-0.0030) and remained significant for all KL grades in adjusted analyses (d = 0.31-0.57, P = 0.0013-0.0361). Results using WOMAC were similar.

CONCLUSIONS

Women reported greater knee pain than men regardless of KL grade, though effect sizes were generally small. These differences increased in the presence of PFOA. The strong contribution of WSP to sex differences in knee pain suggests that central sensitivity plays a role in these differences.

Gender-specific outcome after implantation of low-contact-stress mobile-bearing total knee arthroplasty with a minimum follow-up of ten years

PURPOSE

The study aim was an analysis of gender-specific outcome differences after implantation of the low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) with a minimum follow-up of ten years.

METHODS

We retrospectively analysed 138 prostheses in 108 patients (82 women and 26 men) using our hospital database and a minimum follow-up of ten years (mean 14, range 11-23). Data was extracted with respect to quality of life, clinical outcome parameters [range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, visual analogue scale (VAS), Knee Society Score (KSS), and complications.

RESULTS

At follow-up, we observed no statistically significant differences in all outcome parameters between female and male patients after LCS TKA, except for VAS score, which revealed no clinical relevance due to the low difference (1.53 vs 1.03, p = 0.043).

CONCLUSIONS

Ten years after implantation of the LCS TKA, gender did not influence its beneficial outcome.

Electronic health databases for epidemiological research on joint replacements: considerations when making cross-national comparisons

PURPOSE

The purpose of this study was to examine the rate of primary knee, hip, or shoulder replacement among persons with osteoarthritis (OA) of the knee by gender and age comparing two nations in similar periods using electronic health records, but with different health-care systems.

METHODS

Two electronic health care databases of anonymized information were used to construct cohorts of adults with OA of the knee from the United Kingdom (UK) and the United States. Patients were required to have activity in the database at least 6 months before the first diagnosis of knee OA ("index diagnosis") in the study period to ensure that the patient samples were eligible for medical evaluation. The outcomes (numerator) measured were primary knee, hip, or shoulder replacement or the composite of primary knee, hip, or shoulder replacement. The denominator was the person-time at risk computed from time from the date of the index diagnosis to the date of each outcome separately or to the end of the database period if no outcome was documented.

RESULTS

There were 93,146 subjects in the UK and 1,468,217 in the United States who were aged 18+ years and met the study eligibility criteria. The composite joint replacement rate (hip, knee, or shoulder) ranged from 11.89 per 100 person-years (PY) in the Unites States to 4.13 per 100 PY in the UK Primary knee replacements rates ranged from 10.38 per 100 PY in the Unites States to 3.40 per 100 PY in the UK and occurred at a somewhat higher rate in males than females in both countries. Both primary hip and shoulder replacement rates were higher in the Unites States than in the UK (hip: 1.19 per 100 PY and 0.76 per 100 PY; shoulder: 0.19 per 100 PY and 0.03 per 100 PY, respectively). The median time to a primary hip or knee replacement in the UK was approximately twice as long as in the Unites States.

CONCLUSIONS

Knee replacements are not an uncommon event in persons with knee OA occurring throughout the adult life span, with the rate steeply rising in both sexes until aged 75 years. Although the pattern of the age-specific joint replacement rates was similar between sexes, the magnitude of the rates was markedly lower in the UK.

Prevalence of radiographic osteoarthritis of the knee and its relationship to self-reported pain

Background and Aim

Osteoarthritis (OA) of the knee is one of the most common skeletal disorders, yet little data are available in Asian populations. We sought to assess the prevalence and pattern of radiographic OA of the knee, and its relationship to self-reported pain in a Vietnamese population.

Methods

The study was based on a sample of 170 men and 488 women aged ≥40 years who were randomly sampled from the Ho Chi Minh City (Vietnam). Radiographs of the knee were graded from 0 to 4 according to the Kellgren and Lawrence scale. Osteoarthritis was defined as being present in a knee if radiographic grades of 2 or higher were detected. Knee pain and symptoms were ascertained by direct interview using a structured questionnaire.

Results

The point prevalence of radiographic OA of the knee was 34.2%, with women having higher rate than men (35.3% vs 31.2%). The prevalence of knee OA increased with advancing age: 8% among those aged 40–49 years, 30% in those aged 50–59 years, and 61.1% in those aged ≥60 years. Greater BMI was associated with higher risk of knee OA. Self-reported knee pain was found in 35% of men and 62% of women. There was a statistically significant association between self-reported knee pain and knee OA (prevalence ratio 3.1; 95% CI 2.0 to 4.6).

Conclusions

These data indicate that approximately a third of Vietnamese men and women have radiographic OA in the knee, and that self-reported knee pain may be used as an indicator of knee osteoarthritis.

The TransEurope FootRace Project: longitudinal data acquisition in a cluster randomized mobile MRI observational cohort study on 44 endurance runners at a 64-stage 4,486 km transcontinental ultramarathon

BACKGROUND

The TransEurope FootRace 2009 (TEFR09) was one of the longest transcontinental ultramarathons with an extreme endurance physical load of running nearly 4,500 km in 64 days. The aim of this study was to assess the wide spectrum of adaptive responses in humans regarding the different tissues, organs and functional systems being exposed to such chronic physical endurance load with limited time for regeneration and resulting negative energy balance. A detailed description of the TEFR project and its implemented measuring methods in relation to the hypotheses are presented.

METHODS

The most important research tool was a 1.5 Tesla magnetic resonance imaging (MRI) scanner mounted on a mobile unit following the ultra runners from stage to stage each day. Forty-four study volunteers (67% of the participants) were cluster randomized into two groups for MRI measurements (22 subjects each) according to the project protocol with its different research modules: musculoskeletal system, brain and pain perception, cardiovascular system, body composition, and oxidative stress and inflammation. Complementary to the diverse daily mobile MR-measurements on different topics (muscle and joint MRI, T2*-mapping of cartilage, MR-spectroscopy of muscles, functional MRI of the brain, cardiac and vascular cine MRI, whole body MRI) other methods were also used: ice-water pain test, psychometric questionnaires, bioelectrical impedance analysis (BIA), skinfold thickness and limb circumference measurements, daily urine samples, periodic blood samples and electrocardiograms (ECG).

RESULTS

Thirty volunteers (68%) reached the finish line at North Cape. The mean total race speed was 8.35 km/hour. Finishers invested 552 hours in total. The completion rate for planned MRI investigations was more than 95%: 741 MR-examinations with 2,637 MRI sequences (more than 200,000 picture data), 5,720 urine samples, 244 blood samples, 205 ECG, 1,018 BIA, 539 anthropological measurements and 150 psychological questionnaires.

CONCLUSIONS

This study demonstrates the feasibility of conducting a trial based centrally on mobile MR-measurements which were performed during ten weeks while crossing an entire continent. This article is the reference for contemporary result reports on the different scientific topics of the TEFR project, which may reveal additional new knowledge on the physiological and pathological processes of the functional systems on the organ, cellular and sub-cellular level at the limits of stress and strain of the human body. Please see related articles: http://www.biomedcentral.com/1741-7015/10/76 and http://www.biomedcentral.com/1741-7015/10/77.

Sex-related outcome differences after implantation of low-contact-stress mobile-bearing total knee arthroplasty

PURPOSE

The aim of the study was to investigate outcome differences between female and male patients after implantation of low-contact-stress (LCS) mobile-bearing total knee prostheses at a minimum follow-up of five years with respect to clinical and radiological parameters.

METHODS

We retrospectively analysed 128 prostheses in 126 patients (90 women and 34 men) using our hospital database. Data was extracted with respect to range of motion (ROM), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the Knee Society Score (KSS) and radiolucent lines on conventional X-rays.

RESULTS

At follow-up, we observed no significant differences between female and male patients after LCS total knee prostheses. Benefit after implantation of LCS total knee prostheses after five years of minimum follow-up was not significantly different between female and male patients in terms of clinical outcome or radiolucent lines.

CONCLUSIONS

We found no factors in favour of gender-specific total knee prostheses.

Validity of two simple measures for estimating life-course socio-economic position in cross-sectional postal survey data in an older population: results from the North Staffordshire Osteoarthritis Project (NorStOP)

Background

Since few cohorts encompass the whole life-course, many studies that measure socio-economic position (SEP) across the life-course rely on participant recall of SEP measures from cross-sectional postal or interview surveys. It is also particularly important that SEP measures should be appropriate for the age of the population studied, as the level of missing data has been shown to increase in older people. The aim of this study was to investigate the accuracy of recall of two SEP measures in older adults, age left school and longest job, by examining their validity in a general population postal survey in North Staffordshire, UK.

Methods

Sets of questions on education and longest job were included in a questionnaire at different stages of the study. All patients aged 50+ registered with three general practices were sent a baseline Health Questionnaire. 6 years later, 3410 responders were mailed a follow-up Health Questionnaire; a sub-sample of these participants took part in independent qualitative interviews. Validity was assessed by: percentage completion; internal percentage agreement within each set of questions; percentage agreement of qualitative and quantitative data for age left school and longest job; comparing recall of age left school with historical change in legal school leaving age; comparing frequency of pottery job titles with those in 1981 Census data for Stoke-on-Trent.

Results

The adjusted response to different stages of the study was 71–85%. Completion of questions was 83–98%. Internal agreement was 84–97% (education) and 95–100% (longest job). Comparison of survey and interview data showed 86% agreement (± 1 year) for age left school and 91% agreement for longest job. The change in age left school data concurred with the historical shift in legal school leaving age. 11% of job titles were pottery in NorStOP data and 15% in Stoke-on-Trent Census data.

Conclusions

The results from this study provide evidence for the accuracy of recall of two simple measures of SEP (age left school and longest job) in a postal survey of older adults. Consistency with evidence from external datasets indicated the potential validity of these measures for studying life-course SEP in population surveys.

Association between several clinical and radiological determinants with long-term clinical progression and good prognosis of lower limb osteoarthritis

Objective

To investigate the factors associated with clinical progression and good prognosis in patients with lower limb osteoarthritis (OA).

Methods

Cohort study of 145 patients with OA in either knee, hip or both. Progression was defined as 1) new joint prosthesis or 2) increase in WOMAC pain or function score during 6-years follow-up above pre-defined thresholds. Patients without progression with decrease in WOMAC pain or function score lower than pre-defined thresholds were categorized as good prognosis. Relative risks (RRs) for progression and good prognosis with 95% confidence interval (95% CI) were calculated by comparing the highest tertile or category to the lowest tertile, for baseline determinants (age, sex, BMI, WOMAC pain and function scores, pain on physical examination, total range of motion (tROM), osteophytes and joint space narrowing (JSN) scores), and for worsening in WOMAC pain and function score in 1-year. Adjustments were performed for age, sex, and BMI.

Results

Follow-up was completed by 117 patients (81%, median age 60 years, 84% female); 62 (53%) and 31 patients (26%) showed progression and good prognosis, respectively. These following determinants were associated with progression: pain on physical examination (RR 1.2 (1.0 to 1.5)); tROM (1.4 (1.1 to 1.6); worsening in WOMAC pain (1.9 (1.2 to 2.3)); worsening in WOMAC function (2.4 (1.7 to 2.6)); osteophytes 1.5 (1.0 to 1.8); and JSN scores (2.3 (1.5 to 2.7)). Worsening in WOMAC pain (0.1 (0.1 to 0.8)) and function score (0.1 (0.1 to 0.7)), were negatively associated with good prognosis.

Conclusion

Worsening of self-reported pain and function in one year, limited tROM and higher osteophytes and JSN scores were associated with clinical progression. Worsening in WOMAC pain and function score in 1- year were associated with lower risk to have good prognosis. These findings help to inform patients with regard to their OA prognosis.

Cost-effectiveness of total hip and knee replacements for the Australian population with osteoarthritis: discrete-event simulation model

BACKGROUND

Osteoarthritis constitutes a major musculoskeletal burden for the aged Australians. Hip and knee replacement surgeries are effective interventions once all conservative therapies to manage the symptoms have been exhausted. This study aims to evaluate the cost-effectiveness of hip and knee replacements in Australia. To our best knowledge, the study is the first attempt to account for the dual nature of hip and knee osteoarthritis in modelling the severities of right and left joints separately.

METHODOLOGY/PRINCIPAL FINDINGS

We developed a discrete-event simulation model that follows up the individuals with osteoarthritis over their lifetimes. The model defines separate attributes for right and left joints and accounts for several repeat replacements. The Australian population with osteoarthritis who were 40 years of age or older in 2003 were followed up until extinct. Intervention effects were modelled by means of disability-adjusted life-years (DALYs) averted. Both hip and knee replacements are highly cost effective (AUD 5,000 per DALY and AUD 12,000 per DALY respectively) under an AUD 50,000/DALY threshold level. The exclusion of cost offsets, and inclusion of future unrelated health care costs in extended years of life, did not change the findings that the interventions are cost-effective (AUD 17,000 per DALY and AUD 26,000 per DALY respectively). However, there was a substantial difference between hip and knee replacements where surgeries administered for hips were more cost-effective than for knees.

CONCLUSIONS/SIGNIFICANCE

Both hip and knee replacements are cost-effective interventions to improve the quality of life of people with osteoarthritis. It was also shown that the dual nature of hip and knee OA should be taken into account to provide more accurate estimation on the cost-effectiveness of hip and knee replacements.

Tibiofemoral osteoarthritis affects quality of life and function in elderly Koreans, with women more adversely affected than men

Background

The prevalence of knee osteoarthritis(OA) in East Asia is as common for men and even higher for women than that reported in the Caucasian population. Since both population aging and economic growth have taken place at a much faster pace in Asian countries, such as South Korea, one would expect knee OA to become a major public health problem. However, few studies have examined the influence of knee OA on the quality of life (QoL) and physical function in Asia. The aim of this cross-sectional study is to investigate the influence of knee osteoarthritis (OA) on the quality of life (QoL), function and lower extremity physical performance and the gender difference in its influence in elderly community residents in Korea.

Methods

Participants were from the population-based Hallym Aging Study (HAS). The mean age of the 504 study subjects was 70.2 years and 274 (54%) were women. Demographic information was obtained by questionnaire, and radiographic evaluations consisted of weight-bearing semi-flexed knee radiographs. Self-reported QoL and function were assessed using Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index and Short Form 12-item (SF-12). Performance-based lower extremity function was assessed using the tests consisting of standing balance, usual walk and chair stands. The odds ratios(ORs) for belonging to the worst quartile of WOMAC and physical performance test were calculated by logistic regression analysis in radiographic knee OA compared to non-OA after adjustment of confounders. Scores for SF-12 items were analyzed using general linear models and means adjusted for age, BMI and OA severity were compared.

Results

Subjects with radiographic knee OA had significantly increased OR for belonging to the worst WOMAC quartile(for pain, 2.13,95% confidence interval[CI], 1.33-3.40, for stiffness, 2.94,95% CI,1.78-4.86, and for function, 2.97, 95% CI,1.83-4.81) and significantly worse SF-12 scores compared to non-OA after adjustment of age, BMI and sex. Women had worse WOMAC and SF-12 scores compared to men, regardless of the presence of radiographic knee OA after adjustment of age, BMI and OA severity. OA subjects had significantly worse performance score for usual walk and chair stands compared to non-OA subjects, but the ORs were no more significant after adjustment of sex.

Conclusions

Knee OA negatively affects the QoL and physical function in both genders, but women are more adversely affected than men.

Sex, gender, and pain: a review of recent clinical and experimental findings

Sex-related influences on pain and analgesia have become a topic of tremendous scientific and clinical interest, especially in the last 10 to 15 years. Members of our research group published reviews of this literature more than a decade ago, and the intervening time period has witnessed robust growth in research regarding sex, gender, and pain. Therefore, it seems timely to revisit this literature. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and there is some suggestion that postoperative and procedural pain may be more severe among women than men. Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances. The evidence regarding sex differences in laboratory measures of endogenous pain modulation is mixed, as are findings from studies using functional brain imaging to ascertain sex differences in pain-related cerebral activation. Also inconsistent are findings regarding sex differences in responses to pharmacologic and non-pharmacologic pain treatments. The article concludes with a discussion of potential biopsychosocial mechanisms that may underlie sex differences in pain, and considerations for future research are discussed.

PERSPECTIVE

This article reviews the recent literature regarding sex, gender, and pain. The growing body of evidence that has accumulated in the past 10 to 15 years continues to indicate substantial sex differences in clinical and experimental pain responses, and some evidence suggests that pain treatment responses may differ for women versus men.