Can we identify a 'high risk' patient profile to determine who will experience rapid progression of osteoarthritis?

Mitonuclear epistasis involving TP63 and haplogroup Uk: Risk of rapid progression of knee OA in patients from the OAI

OBJECTIVE

To investigate genetic interactions between mitochondrial deoxyribonucleic acid (mtDNA) haplogroups and nuclear single nucleotide polymorphisms (nSNPs) to analyze their impact on the development of the rapid progression of knee osteoarthritis (OA).

DESIGN

A total of 1095 subjects from the Osteoarthritis Initiative, with a follow-up time of at least 48-months, were included. Appropriate statistical approaches were performed, including generalized estimating equations adjusting for age, gender, body mass index, contralateral knee OA, Western Ontario and McMaster Universities Osteoarthritis Index pain, previous injury in target knee and the presence of the mtDNA variant m.16519C. Additional genomic data consisted in the genotyping of Caucasian mtDNA haplogroups and eight nSNPs previously associated with the risk of knee OA in robust genome-wide association studies.

RESULTS

The simultaneous presence of the G allele of rs12107036 at TP63 and the haplogroup Uk significantly increases the risk of a rapid progression of knee OA (odds ratio = 1.670; 95% confidence interval [CI]: 1.031-2.706; adjusted p-value = 0.027). The assessment of the population attributable fraction showed that the highest proportion of rapid progressors was under the simultaneous presence of the G allele of rs12107036 and the haplogroup Uk (23.4%) (95%CI: 7.89-38.9; p-value < 0.05). The area under the curve of the cross-validation model (0.730) was very similar to the obtained for the predictive model (0.735). A nomogram was constructed to help clinicians to perform clinical trials or epidemiologic studies.

CONCLUSIONS

This study demonstrates the existence of a mitonuclear epistasis in OA, providing new mechanisms by which nuclear and mitochondrial variation influence the susceptibility to develop different OA phenotypes.

An osteoarthritis pathophysiological continuum revealed by molecular biomarkers

We aimed to identify serum biomarkers that predict knee osteoarthritis (OA) before the appearance of radiographic abnormalities in a cohort of 200 women. As few as six serum peptides, corresponding to six proteins, reached AUC 77% probability to distinguish those who developed OA from age-matched individuals who did not develop OA up to 8 years later. Prediction based on these blood biomarkers was superior to traditional prediction based on age and BMI (AUC 51%) or knee pain (AUC 57%). These results identify a prolonged molecular derangement of joint tissue before the onset of radiographic OA abnormalities consistent with an unresolved acute phase response. Among all 24 protein biomarkers predicting incident knee OA, the majority (58%) also predicted knee OA progression, revealing the existence of a pathophysiological "OA continuum" based on considerable similarity in the molecular pathophysiology of the progression to incident OA and the progression of established OA.

Mincing bovine articular cartilage with commercially available shavers reduces the viability of chondrocytes compared to scalpel mincing

PURPOSE

The study aimed to compare the effect of mincing bovine articular cartilage with different shaver blades on chondrocyte viability.

METHODS

Bovine articular cartilage was harvested either with a scalpel or with three different shaver blades (2.5 mm, 3.5 mm, or 4.2 mm) from a commercially available shaver. The cartilage harvested with a scalpel was then minced into fragments smaller than 1 mm3 with a scalpel. All four conditions were cultivated in a culture medium for seven days. After Day 1 and Day 7, the following measurements were performed: metabolic activity, RNA isolation, and gene expression of anabolic (COL2A1 and ACAN) and catabolic genes (MMP1 and MMP13), live/dead staining and visualization using confocal microscopy, and flow cytometric characterization of minced cartilage chondrocytes.

RESULTS

Mincing the cartilage with shavers significantly reduced metabolic activity after one and seven days compared to scalpel mincing (p < 0.001). Gene expression of anabolic genes (COL2A1 and ACAN) was reduced, while catabolic genes (MMP1 and MMP13) were increased after day 7 in all shaver conditions. Confocal microscopy showed a thin line of dead cells at the lesion side with viable cells beneath for the scalpel mincing and a higher number of dead cells diffusely distributed in the shaver conditions. After seven days, there was a significant decrease in viable cells in the shaver conditions compared to scalpel mincing (p < 0.05). Flow cytometric characterization revealed fewer intact cells and proportionally more dead cells in all shaver conditions compared to the scalpel mincing.

CONCLUSION

Mincing bovine articular cartilage with commercially available shavers reduces the viability of chondrocytes compared to scalpel mincing immediately after harvest and after seven days in culture. This suggests that mincing cartilage with a shaver should be considered a matrix rather than a cell therapy.

LEVEL OF EVIDENCE

Level II therapeutic study.

Cationic Carrier Mediated Delivery of Anionic Contrast Agents in Low Doses Enable Enhanced Computed Tomography Imaging of Cartilage for Early Osteoarthritis Diagnosis

Cartilage tissue exhibits early degenerative changes with onset of osteoarthritis (OA). Early diagnosis is critical as there is only a narrow time window during which therapeutic intervention can reverse disease progression. Computed tomography (CT) has been considered for cartilage imaging as a tool for early OA diagnosis by introducing radio-opaque contrast agents like ioxaglate (IOX) into the joint. IOX, however, is anionic and thus repelled by negatively charged cartilage glycosaminoglycans (GAGs) that hinders its intra-tissue penetration and partitioning, resulting in poor CT attenuation. This is further complicated by its short intra-tissue residence time owing to rapid clearance from joints, which necessitates high doses causing toxicity concerns. Here we engineer optimally charged cationic contrast agents based on cartilage negative fixed charge density by conjugating cartilage targeting a cationic peptide carrier (CPC) and multi-arm avidin nanoconstruct (mAv) to IOX, such that they can penetrate through the full thickness of cartilage within 6 h using electrostatic interactions and elicit similar CT signal with about 40× lower dose compared to anionic IOX. Their partitioning and distribution correlate strongly with spatial GAG distribution within healthy and early- to late-stage arthritic bovine cartilage tissues at 50-100× lower doses than other cationic contrast agents used in the current literature. The use of contrast agents at low concentrations also allowed for delineation of cartilage from subchondral bone as well as other soft tissues in rat tibial joints. These contrast agents are safe to use at current doses, making CT a viable imaging modality for early detection of OA and staging of its severity.

Exploring High-Throughput Immunoassays for Biomarker Validation in Rheumatic Diseases in the Context of the Human Proteome Project

Rheumatic diseases are high prevalence pathologies with different etiology and evolution and low sensitivity in clinical diagnosis. Therefore, it is necessary to develop an early diagnosis method which allows personalized treatment, depending on the specific pathology. The biology/disease initiative, at Human Proteome Project, is an integrative approach to identify relevant proteins in the human proteome associated with pathologies. A previously reported literature data mining analysis, which identified proteins related to osteoarthritis (OA), rheumatoid arthritis (RA), and psoriatic arthritis (PSA) was used to establish a systematic prioritization of potential biomarkers candidates for further evaluation by functional proteomics studies. The aim was to study the protein profile of serum samples from patients with rheumatic diseases such as OA, RA, and PSA. To achieve this goal, customized antibody microarrays (containing 151 antibodies targeting 121 specific proteins) were used to identify biomarkers related to early and specific diagnosis in a screening of 960 serum samples (nondepleted) (OA, n = 480; RA, n = 192; PSA, n = 288). This functional proteomics screening has allowed the determination of a panel (30 serum proteins) as potential biomarkers for these rheumatic diseases, displaying receiver operating characteristics curves with area under the curve values of 80-90%.

Ingredients of a Natural Oral Nutritional Supplement and Their Role in the Treatment of Osteoarthritis

Osteoarthritis is a prevalent degenerative disease affecting a large portion of the world’s aging population. Currently, nonsteroidal anti-inflammatory drugs and acetaminophen are first-line medications for treating osteoarthritis patients’ pain. However, several studies have noted that while these medications control pain they do not halt progressive degeneration and tend to have an unfavorable side-effect profile with prolonged use. Recently, due to their more favorable side-effect profiles, herbal alternatives for controlling osteoarthritis symptoms and for alleviating the progression of the disease are being increasingly studied. Synogesic is a newly developed herbal supplement blend by renowned orthopedic surgeons and physiatrists consisting of turmeric, rutin, ginger root, vitamin C, vitamin D, and boswellia extracts. A study by Sharkey et al. has commented on the efficacy of the blend on the patients with knee osteoarthritis. So far, a review on the ingredients of the blend has not yet carried outbeen. By exploring prominent literature databases including PubMed and ScienceDirect, our aim is to write a narrative review to explore the individual ingredients of this blend and delve into their characteristics, as well as the most recent literature on their mechanism and efficacy in patients with osteoarthritis. Through this, we hope to inform clinicians and patients alike on relevant up-to-date research on the supplement and provide insight on the potential for this supplement for alleviating the disease course of patients with osteoarthritis.

Surgical management for primary osteoarthritis of the elbow

The objective of this review is to summarize the surgical options for primary osteoarthritis of the elbow, reported clinical outcomes, and suggested indications in previous literatures. The surgical management of primary elbow arthritis has evolved because of an improved understanding of pathologic mechanisms and manifestations as well as the development of novel surgical techniques and devices. Osteocapsular arthroplasty (OCA), elbow debridement, distraction arthroplasty, and total elbow arthroplasty (TEA) have been employed for managing elbow osteoarthritis. Elbow debridement and OCA can be helpful in most cases of symptomatic elbow arthritis. TEA is usually recommended for end-stage arthritis in elderly patients after prosthetic implants have been in place for long periods or after complications. Distraction arthroplasty might find a place in the treatment of younger, active patients with end-stage arthritis.

The implications of an aging population and increased obesity for knee arthroplasty rates in Sweden: a register-based study

Background and purpose - Total knee arthroplasty (TKA) has increased substantially in Sweden. We quantified the relative risk for TKA in the Swedish population for different BMI categories and age groups to investigate whether the continued increase in TKA is attributable to increased prevalence of obesity and elderly people in the population, and to put forward model predictions for coming needs for TKA. Patients and methods - We used the Swedish Nationwide Health Survey (SNHS) and the Swedish Knee Arthroplasty Register (SKAR) 2009-2015 to calculate the relative risk (RR) of TKA by age (middle-aged 45-64 years and elderly 65-84 years) and BMI (BMI 18.5-24.9 normal weight; BMI 25.0-29.9 overweight; BMI > 30 obese). The RR for TKA was applied to the demographic forecasts for the Swedish population as a forecasting model. Results - Population size increased 5.2% from 2009 to 2015 to 40,000 middle-aged and 250,000 elderly, and the prevalence of obesity increased from 16% to 18% in these 2 age categories. Compared with those of normal weight, the RR for TKA was 2.7 (95% CI 2.5-3.0) higher for the overweight and 7.3 (6.7-8.0) higher for the obese, aged 45-64. The corresponding figures for individuals aged 65-84 were 2.1 (2.0-2.2) and 4.0 (3.8-4.3) higher, respectively. The changes in the prevalence of obesity and an increase in the elderly population accounted for an estimated increase of 1,700 TKAs over the 7 years. Interpretation - The increase in obesity frequency and the rise in the population of middle-aged and elderly may, to some extent, explain the rise in TKA utilization in Sweden.

Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought?

Osteoarthritis (OA) of the hip and knee is among the most common joint disorders. Intra-articular corticosteroid (IACS) injections are frequently performed to treat OA and other joint-related pain syndromes; however, there is conflicting evidence on their potential benefit. There is a lack of prospective and large retrospective studies evaluating potential joint findings, including increased risk for accelerated OA progression or adverse joint events, after treatment with IACS injection. Four main adverse joint findings have been structurally observed in patients after IACS injections: accelerated OA progression, subchondral insufficiency fracture, complications of osteonecrosis, and rapid joint destruction, including bone loss. Physicians, including radiologists, should be familiar with imaging findings and patient characteristics that may help them identify potential joints at risk for such events. The purpose of this report is to review the existing literature, describe observed adverse joint events after IACS injections, and provide an outlook on how this may affect clinical practice. Additional research endeavors are urgently needed to better understand and identify risk factors prior to intervention and to detect adverse joint events after injection as early as possible to prevent or minimize complications.

From Early Radiographic Knee Osteoarthritis to Joint Arthroplasty: Determinants of Structural Progression and Symptoms

OBJECTIVE

To assess structural progression in knees with no/mild radiographic osteoarthritis (OA) (i.e., Kellgren/Lawrence [K/L] grades 0-2) that will undergo knee replacement during a 5-year period; to assess differences in structural damage on magnetic resonance imaging (MRI) in knees with no/mild radiographic OA versus those with severe radiographic OA (i.e., K/L grades 3 and 4) at baseline; and to assess differences in pain levels between those groups.

METHODS

All participants who underwent knee replacement from baseline to 60 months were drawn from the Osteoarthritis Initiative. MRIs were assessed for bone marrow lesions (BMLs), Hoffa synovitis, and effusion synovitis (i.e., hyperintensity signal changes in the fat pad and abnormal amount of capsular distension due to intraarticular joint fluid and/or synovial thickening) at baseline and at the time point before knee replacement (T0). The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) pain were used for pain characterization. WOMAC activities of daily living and KOOS quality of life were applied to characterize functional status of the included participants. Logistic regression was used to assess the association of no/mild radiographic OA with these MRI features and pain.

RESULTS

Based on inclusion criteria, 181 knees were selected. Participants were predominantly female (57.8%) with a mean age of 64.4 years. A total of 51 knees (28.2%) had no/mild radiographic OA at baseline. Of these, 51.0% progressed to severe radiographic OA. No/mild radiographic OA knees showed higher odds of BMLs in the patellofemoral joint at baseline (odds ratio [OR] 7.92 [95% confidence interval (95% CI) 3.45-18.16]) and T0 (OR 9.44 [95% CI 4.00-22.28]) compared to severe radiographic OA knees. In addition, no/mild radiographic OA knees were associated with change from no pain to pain from baseline to T0 (adjusted OR 5.48 [95% CI 1.25-24.00]).

CONCLUSION

More than half of the knees with no/mild radiographic OA before knee replacement progressed to severe radiographic OA during 4 years of follow-up. BMLs in the patellofemoral joint were more often seen among knees that had no/mild radiographic OA. Worsening pain status may contribute to knee replacement in knees with no/mild radiographic OA.

Kinematics of meniscal- and ACL-transected mouse knees during controlled tibial compressive loading captured using roentgen stereophotogrammetry

Pre-clinical studies of post-traumatic OA have examined the pathways that lead to disease after injury by using surgical models such as the destabilization of the medial meniscus (DMM) and anterior cruciate ligament transection (ACLT). While the morphological, molecular, and genetic pathways leading to OA have been examined extensively; the effects of these injuries on joint kinematics, and thus disease progression, have yet to be fully characterized. To this end, we sought to understand the kinematics in the DMM and ACLT joints compared to intact joints subjected to controlled tibial compressive loading. We hypothesized that the DMM and ACLT models would result in different patterns of joint instability compared to intact joints, thus explaining the different patterns of OA initiation and severity in these models. Cadaver adult C57BL/6 mice were subjected to either a DMM or ACLT in their right knee joints, while the left limbs remained as intact controls. All limbs were labeled with fiducial markers, and the rigid body kinematics of the tibia and femur were examined using roentgen stereophotogrammetry (RSA) with application of compressive loads from 0 to 9 N. DMM and intact joints demonstrated similar kinematics under compressive loading, in contrast to ACLT joints, which dislocated even before load application. These results demonstrate the importance of rigorous kinematic analysis in defining the role of joint instability in animal models of OA and suggest significant differences in DMM and ACLT joint instabilities in the context of controlled mechanical loading. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:353-360, 2017.

Best performing definition of accelerated knee osteoarthritis: data from the Osteoarthritis Initiative

BACKGROUND

We evaluated agreement among several definitions of accelerated knee osteoarthritis (AKOA) and construct validity by comparing their individual associations with injury, age, obesity, and knee pain.

METHODS

We selected knees from the Osteoarthritis Initiative that had no radiographic knee osteoarthritis [Kellgren-Lawrence (KL) 0 or 1] at baseline and had high-quality quantitative medial joint space width (JSW) measures on two or more consecutive visits (n = 1655 knees, 1143 participants). Quantitative medial JSW was based on a semi-automated method and was location specific (x = 0.25). We compared six definitions of AKOA: stringent JSW (averaged): average JSW loss greater than 1.05 mm/year over 4 years; stringent JSW (consistent): JSW loss greater than 1.05 mm/year for at least 2 years; lenient JSW (averaged): average JSW loss greater than 0.25 mm/year over 4 years; lenient JSW (consistent): JSW loss greater than 0.25 mm/year for at least 2 years; comprehensive KL based: progression from no radiographic osteoarthritis to advance-stage osteoarthritis (KL 3 or 4; development of definite osteophyte and joint space narrowing) within 4 years; and lenient KL based: an increase of at least two KL grades within 4 years.

RESULTS

Over 4 years the incidence rate of AKOA was 0.4%, 0.8%, 15.5%, 22.1%, 12.4%, and 7.2% based on the stringent JSW (averaged and consistent), lenient JSW (averaged and consistent), lenient KL-based definition, and comprehensive KL-based definition. All but one knee that met the stringent JSW definition also met the comprehensive KL-based definition. There was fair substantial agreement between the lenient JSW (averaged), lenient KL-based, and comprehensive KL-based definitions. A comprehensive KL-based definition led to larger effect sizes for injury, age, body mass index, and average pain over 4 years.

CONCLUSIONS

A comprehensive KL-based definition of AKOA may be ideal because it represents a broader definition of joint deterioration compared with those focused on just joint space or osteophytes alone.

Can we identify patients with high risk of osteoarthritis progression who will respond to treatment? A focus on epidemiology and phenotype of osteoarthritis

Osteoarthritis is a syndrome affecting a variety of patient profiles. A European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and the European Union Geriatric Medicine Society working meeting explored the possibility of identifying different patient profiles in osteoarthritis. The risk factors for the development of osteoarthritis include systemic factors (e.g., age, sex, obesity, genetics, race, and bone density) and local biomechanical factors (e.g., obesity, sport, joint injury, and muscle weakness); most also predict disease progression, particularly joint injury, malalignment, and synovitis/effusion. The characterization of patient profiles should help to better orientate research, facilitate trial design, and define which patients are the most likely to benefit from treatment. There are a number of profile candidates. Generalized, polyarticular osteoarthritis and local, monoarticular osteoarthritis appear to be two different profiles; the former is a feature of osteoarthritis co-morbid with inflammation or the metabolic syndrome, while the latter is more typical of post-trauma osteoarthritis, especially in cases with severe malalignment. Other biomechanical factors may also define profiles, such as joint malalignment, loss of meniscal function, and ligament injury. Early- and late-stage osteoarthritis appear as separate profiles, notably in terms of treatment response. Finally, there is evidence that there are two separate profiles related to lesions in the subchondral bone, which may determine benefit from bone-active treatments. Decisions on appropriate therapy should be made considering clinical presentation, underlying pathophysiology, and stage of disease. Identification of patient profiles may lead to more personalized healthcare, with more targeted treatment for osteoarthritis.

The effect of tibial rotation on knee medial and lateral compartment contact pressure

PURPOSE

The progression of knee osteoarthritis (OA) is determined in part by mechanical effects on local structures. The mechanical influences of limb malalignment on cartilage loss are well known; however, the effect of rotational deformities on knee OA is not yet known. The aim of the current study was to evaluate the effect of tibial rotation on knee medial and lateral compartment contact pressure.

METHODS

The left knees of six fresh whole-body cadavers were used in this study. Fujifilm Prescale super-low type film was used for contact pressure measurement. The films were inserted into the joint after arthrotomy. The cadavers were stabilized with a custom-made device, and axial force of half body weight specific to each cadaver was applied to the plantar surface of the feet. The examination was repeated after osteotomy of the fibula and tibia, and the tibia was then rotated 15° or 30° internally (IR) or externally (ER) and securely fixed. The resulting films were scanned, and CP was determined using appropriate software.

RESULTS

The p values for increased medial compartment contact pressure at 15° and 30° IR and 30° ER were 0.016, 0.025, and 0.025, respectively. For decreased medial compartment contact pressure at 15° ER, the p value was 0.020. The p values for increased lateral compartment contact pressure at 15° and 30° ER were 0.010 and 0.030, respectively. In this compartment, contact pressure changes at 15° and 30° IR were not significant.

CONCLUSION

This experimental study demonstrated that 15° IR of the tibial shaft increased contact pressure and 15° ER decreased contact pressure over the knee medial compartment.

Can We Identify Patients with High Risk of Osteoarthritis Progression Who Will Respond to Treatment? A Focus on Biomarkers and Frailty

Osteoarthritis (OA), a disease affecting different patient phenotypes, appears as an optimal candidate for personalized healthcare. The aim of the discussions of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) working group was to explore the value of markers of different sources in defining different phenotypes of patients with OA. The ESCEO organized a series of meetings to explore the possibility of identifying patients who would most benefit from treatment for OA, on the basis of recent data and expert opinion. In the first meeting, patient phenotypes were identified according to the number of affected joints, biomechanical factors, and the presence of lesions in the subchondral bone. In the second meeting, summarized in the present article, the working group explored other markers involved in OA. Profiles of patients may be defined according to their level of pain, functional limitation, and presence of coexistent chronic conditions including frailty status. A considerable amount of data suggests that magnetic resonance imaging may also assist in delineating different phenotypes of patients with OA. Among multiple biochemical biomarkers identified, none is sufficiently validated and recognized to identify patients who should be treated. Considerable efforts are also being made to identify genetic and epigenetic factors involved in OA, but results are still limited. The many potential biomarkers that could be used as potential stratifiers are promising, but more research is needed to characterize and qualify the existing biomarkers and to identify new candidates.

Sustained efficacy of a single intra-articular dose of FX006 in a rat model of repeated localized knee arthritis

OBJECTIVE

To evaluate the efficacy of a single intra-articular (IA) dose of FX006, an extended-release formulation of triamcinolone acetonide (TCA) in poly(lactic-co-glycolic acid) (PLGA) microspheres, on the sequelae of repeated episodes of synovitis.

DESIGN

Three flares of localized synovitis in the right knee of rats were induced over 4 weeks following a single IA injection of various doses of FX006, Kenalog(®) (TCA immediate release or TCA IR), or vehicle. Gait scores were employed to assess analgesic effect, and the joints were evaluated by histology at the end of the study. TCA plasma concentrations and corticosterone levels were monitored through the study.

RESULTS

A single IA dose of 0.28 mg FX006 significantly improved gait scores through all three reactivations. TCA IR at 0.06 mg (providing comparable plasma TCA exposure, 10-fold higher Cmax) demonstrated comparable benefit through the first reactivation only and reduced-to-no efficacy thereafter. Significantly improved histological joint scores were observed with effective doses of FX006 but not with TCA IR. Corticosterone levels were initially decreased following both TCA IR and FX006 treatment, but recovered by Day 14.

CONCLUSIONS

In localized, repeated synovitis in rats, sustained release of TCA following a single IA injection of FX006 significantly prolonged analgesia relative to TCA IR and significantly improved histological scores with no adverse effect on the HPA axis. Since synovitis can contribute to the pathophysiology of multiple joint diseases such as osteoarthritis (OA), RA and gout, FX006 may be an important treatment option for these conditions.

Association of knee injuries with accelerated knee osteoarthritis progression: data from the Osteoarthritis Initiative

OBJECTIVE

We aimed to evaluate whether a recent knee injury was associated with accelerated knee osteoarthritis (OA) progression.

METHODS

In the Osteoarthritis Initiative, we studied participants free of knee OA on their baseline radiographs (Kellgren/Lawrence [K/L] <2). We compared 3 groups as follows: 1) individuals with accelerated progression of knee OA: defined as having at least 1 knee that progressed to end-stage knee OA (K/L grade 3 or 4) within 48 months, 2) common knee OA progression: at least 1 knee increased in radiographic scoring within 48 months (excluding those defined as accelerated knee OA), and 3) no knee OA: no change in K/L grade in either knee. At baseline, participants were asked if their knees had ever been injured, and at each annual visit they were asked about injuries during the prior 12 months. We used multinomial logistic regressions to determine whether a new knee injury was associated with the outcome of accelerated knee OA or common knee OA progression, after adjusting for age, sex, body mass index, static knee malalignment, and systolic blood pressure.

RESULTS

A knee injury during the total observation period was associated with accelerated knee OA progression (n = 54; odds ratio [OR] 3.14) but not common knee OA progression (n = 187; OR 1.08). Furthermore, a more recent knee injury (within a year of the outcome) was associated with accelerated (OR 8.46) and common knee OA progression (OR 3.12).

CONCLUSION

Recent knee injuries are associated with accelerated knee OA. Most concerning is that certain injuries may be associated with a rapid cascade toward joint failure in less than 1 year.

Knee osteoarthritis: Clinical connections to articular cartilage structure and function

Articular cartilage is a unique biphasic material that supports a lifetime of compressive and shear forces across joints. When articular cartilage deteriorates, whether due to injury, wear and tear or normal aging, osteoarthritis and resultant pain can ensue. Understanding the basic science of the structure and biomechanics of articular cartilage can help clinicians guide their patients to appropriate activity and loading choices. The purpose of this article is to examine how articular cartilage structure and mechanics, may interact with risk factors to contribute to OA and how this interaction provides guidelines for intervention choices This paper will review the microstructure of articular cartilage, its mechanical properties and link this information to clinical decision making.

Structural changes in the knee during weight loss maintenance after a significant weight loss in obese patients with osteoarthritis: a report of secondary outcome analyses from a randomized controlled trial

OBJECTIVE

To compare structural knee joint changes in obese patients with knee osteoarthritis (OA) that after an intensive weight loss therapy were randomized to continuous dietetic support, a specialized knee exercise program, or 'no attention' for 1 year.

METHODS

192 obese individuals with knee OA underwent an intensive 16-week weight loss program with subsequent randomization to one of the three treatment groups. Changes in cartilage loss, bone marrow lesions (BMLs), synovitis, and effusion were assessed using semi quantitative assessments of magnetic resonance imaging (MRI) obtained at weeks 0 and 68 applying the BLOKS score.

RESULTS

During the 52 weeks maintenance period the continuous dietary maintenance group support on average gained 1.1 kg (95% CI: -0.3:2.5) body mass, the exercise group gained 6.6 kg (95% CI 5.4:7.8) and the no-attention group gained 4.8 kg (95% CI: 2.9:6.7). There were no statistically significant between-group differences in changes in cartilage loss, synovitis or effusion at the follow-up (analysis of covariance; ANCOVA, P > 0.16), while there was an increased number of medial tibiofemoral BMLs in the exercise group (ANCOVA, P = 0.015) compared to both diet (difference: -0.21 [95%CI -0.40:-0.03]) and "no attention" (difference: -0.26 [95%CI -0.44:-0.07]) groups.

CONCLUSION

In this 1 year follow-up after weight-loss in obese knee OA patients, we found a potentially increased number of BMLs in the exercise group compared to the diet and no attention groups, with no between-group differences in changes in cartilage loss, synovitis or effusion. These findings should be interpreted with caution for exercise compliance, MRI methodology and follow-up time. (ClinicalTrials.gov identifier: NCT00655941).

TSG-6 activity as a novel biomarker of progression in knee osteoarthritis

OBJECTIVE

To establish whether there is an association between TSG-6 activity and osteoarthritis progression.

DESIGN

TSG-6 activity was determined in 132 synovial fluids from patients with OA of the knee, using a novel quantitative TSG-6 activity assay. The association between TSG-6 activities at baseline and four distinct disease progression states, determined at 3-year follow-up, was analyzed using logistic regression.

RESULTS

There was a statistically significant relationship between TSG-6 activity at baseline and all OA progression states over a 3-year period. Patient knees with TSG-6 activities in the top tenth percentile, compared to the median activity, had an odds ratio (OR) of at least 7.86 (confidence interval (CI) [3.2, 20.5]) for total knee arthroplasty (TKA) within 3 years, and of at least 5.20 (CI [1.8, 13.9]) after adjustment for confounding factors. Receiver operating characteristic (ROC) analysis for knee arthroplasty yielded a cut-off point of 13.3 TSG-6 activity units/ml with the following parameters: area under the curve 0.90 (CI [0.804, 0.996]), sensitivity 0.91 (CI [0.59, 0.99]), specificity 0.82 (CI [0.74, 0.88]) and a negative predictive value (NPV) of 0.99 (CI [0.934, 0.994]).

CONCLUSION

The TSG-6 activity is a promising independent biomarker for OA progression. Given the high NPV, this assay may be particularly suitable for identifying patients at low risk of rapid disease progression and to assist in the timing of arthroplasty.

Customized foot insoles have a positive effect on pain, function, and quality of life in patients with medial knee osteoarthritis

BACKGROUND

Knee osteoarthritis (KOA) is a prevalent degenerative disease in older adults. Treatment strategies, including insoles, focus on reducing pain and physical disability. In medial KOA, insoles have been studied extensively with conflicting results, possibly due to heterogeneity in outcome measures and the intervention. We sought to investigate the effect of custom-made laterally wedged insoles on pain, function, and quality of life in patients with medial KOA.

METHODS

Fifty-one consecutive patients with medial KOA were prescribed custom-made insoles with arch support and a 5.0° to 8.7° lateral wedge. At follow-up, 42 of the 51 participants (22 men; mean age, 63 years; mean Kellgren-Lawrence, 3.4) participated. Retrospectively, participants were asked to rate the pain intensity in their affected knee before and after the intervention measured on a visual analog scale after 30 min of physical activity (primary outcome), at rest, at night, and after 50 m of walking. Additionally, they completed the Oxford Knee Score and the EQ-5D. The paired-samples t test was applied in the statistics.

RESULTS

The visual analog scale score after 30 min of physical activity was significantly reduced after the intervention (mean, 3.3 cm; 95% confidence interval, 2.1-4.5 cm; P < .001). The same significant changes were found in all of the secondary outcomes.

CONCLUSIONS

There was a significant reduction in pain and improvements in function and quality of life with custom-made laterally wedged insoles with arch support in older adults with mild-to-severe medial KOA. The customization of laterally wedged insoles may be essential for the effect in medial KOA.

The measurement of joint mechanics and their role in osteoarthritis genesis and progression

Mechanics play a role in the initiation and progression of osteoarthritis. However, our understanding of which mechanical parameters are most important, and what their impact is on the disease, is limited by the challenge of measuring the most important mechanical quantities in living subjects. Consequently, comprehensive statements cannot be made about how mechanics should be modified to prevent, slow or arrest osteoarthritis. Our current understanding is based largely on studies of deviations from normal mechanics caused by malalignment, injury, and deformity. Some treatments for osteoarthritis focus on correcting mechanics, but there appears to be scope for more mechanically based interventions.

Predicting knee cartilage loss using adaptive partitioning of cartilage thickness maps

This study investigates whether measures of knee cartilage thickness can predict future loss of knee cartilage. A slow and a rapid progressor group was determined using longitudinal data, and anatomically aligned cartilage thickness maps were extracted from MRI at baseline. A novel machine learning framework was then trained using these maps. Compared to measures of mean cartilage plate thickness, group separation was increased by focusing on local cartilage differences. This result is central for clinical trials where inclusion of rapid progressors may help reduce the period needed to study effects of new disease-modifying drugs for osteoarthritis.

Obesity and reduction of the response rate to anti-tumor necrosis factor α in rheumatoid arthritis: an approach to a personalized medicine

OBJECTIVE

Obesity is a mild, long-lasting inflammatory disease and, as such, could increase the inflammatory burden of rheumatoid arthritis (RA). The study aim was to determine whether obesity represents a risk factor for a poor remission rate in RA patients requiring anti-tumor necrosis factor α (anti-TNFα) therapy for progressive and active disease despite treatment with methotrexate or other disease-modifying antirheumatic drugs.

METHODS

Patients were identified from 15 outpatient clinics of university hospitals and hospitals in Italy taking part in the Gruppo Italiano di Studio sulle Early Arthritis network. Disease Activity Score in 28 joints (DAS28), body mass index (BMI; categorized as <25, 25-30, and >30 kg/m(2) ), acute-phase reactants, IgM rheumatoid factor, and anti-cyclic citrullinated peptide antibody values were collected. DAS28 remission was defined as a score of <2.6 lasting for at least 3 months.

RESULTS

Six hundred forty-one outpatients with longstanding RA receiving anti-TNFα blockers (adalimumab, n = 260; etanercept, n = 227; infliximab, n = 154), recruited from 2006-2009 and monitored for at least 12 months, were analyzed. The mean ± SD DAS28 at baseline was 5.6 ± 1.4. A BMI of >30 kg/m(2) was recorded in 66 (10.3%) of 641 RA patients. After 12 months of anti-TNFα treatment, a DAS28 of <2.6 was noted in 15.2% of the obese subjects, in 30.4% of the patients with a BMI of 25-30 kg/m(2) , and in 32.9% of the patients with a BMI of <25 kg/m(2) (P = 0.01). The lowest percentage of remission, which was statistically significant versus adalimumab and etanercept (P = 0.003), was observed with infliximab.

CONCLUSION

Obesity represents a risk factor for a poor remission rate in patients with longstanding RA treated with anti-TNFα agents. A personalized treatment plan might be a possible solution.

Body mass index affects knee joint mechanics during gait differently with and without moderate knee osteoarthritis

OBJECTIVE

Obesity is a highly cited risk factor for knee osteoarthritis (OA), but its role in knee OA pathogenesis and progression is not as clear. Excess weight may contribute to an increased mechanical burden and altered dynamic movement and loading patterns at the knee. The objective of this study was to examine the interacting role of moderate knee OA disease presence and obesity on knee joint mechanics during gait.

METHODS

Gait analysis was performed on 104 asymptomatic and 140 individuals with moderate knee OA. Each subject group was divided into three body mass categories based on body mass index (BMI): healthy weight (BMI<25), overweight (25≤BMI≤30), and obese (BMI>30). Three-dimensional knee joint angles and net external knee joint moments were calculated and waveform principal component analysis (PCA) was applied to extract major patterns of variability from each. PC scores for major patterns were compared between groups using a two-factor ANOVA.

RESULTS

Significant BMI main effects were found in the pattern of the knee adduction moment, the knee flexion moment, and the knee rotation moment during gait. Two interaction effects between moderate OA disease presence and BMI were also found that described different changes in the knee flexion moment and the knee flexion angle with increased BMI with and without knee OA.

CONCLUSION

Our results suggest that increased BMI is associated with different changes in biomechanical patterns of the knee joint during gait depending on the presence of moderate knee OA.

Genetic risk load and age at symptom onset of knee osteoarthritis

To test whether a higher genetic risk load for knee osteoarthritis (OA) is associated with an earlier age at symptom onset. Six polymorphisms in GDF5, PTGS2, 7q22 locus, DVWA, DIO3, and ASPN that have been associated with knee OA were analyzed in 255 patients that had undergone total knee replacement (TKR) because of primary OA and in 457 healthy controls. We looked for association between the number of risk alleles in each patient and his age at symptom onset with linear regression and t-tests between the upper and lower quartiles. There was not even a weak trend in the direction of a younger age at symptom onset in the patients carrying more risk alleles. Patients in the upper quartile of age at symptom onset (67.0 ± 2.8 years) carried the same number of OA risk alleles (5.4 ± 1.4 vs. 5.3 ± 1.0) than patients in the lower quartile (44.6 ± 5.5 years). We did not find any evidence in support of the hypothesis of an earlier knee OA symptom onset associated with higher genetic risk load as determined by the six loci. This result suggests that old age and genetic risk act as independent factors in the pathogenesis of OA. It also indicates that designing OA genetic studies with patients selected for early symptom onset will not provide any substantial power gain.

Obesity and symptomatic osteoarthritis of the knee

Given the growing prevalence of obesity around the world and its association with osteoarthritis of the knee, orthopaedic surgeons need to be familiar with the management of the obese patient with degenerative knee pain. The precise mechanism by which obesity leads to osteoarthritis remains unknown, but is likely to be due to a combination of mechanical, humoral and genetic factors. Weight loss has clear medical benefits for the obese patient and seems to be a logical way of relieving joint pain associated with degenerative arthritis. There are a variety of ways in which this may be done including diet and exercise, and treatment with drugs and bariatric surgery. Whether substantial weight loss can delay or even reverse the symptoms associated with osteoarthritis remains to be seen. Surgery for osteoarthritis in the obese patient can be technically more challenging and carries a risk of additional complications. Substantial weight loss before undertaking total knee replacement is advisable. More prospective studies that evaluate the effect of significant weight loss on the evolution of symptomatic osteoarthritis of the knee are needed so that orthopaedic surgeons can treat this patient group appropriately.

Identification of phenotypes with different clinical outcomes in knee osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVE

To identify subgroups or phenotypes of knee osteoarthritis (OA) patients based on similarities of clinically relevant patient characteristics, and to compare clinical outcomes of these phenotypes.

METHODS

Data from 842 knee OA patients of the Osteoarthritis Initiative were used. A cluster analysis method was performed, in which clusters were formed based on similarities in 4 clinically relevant, easily available variables: severity of radiographic OA, lower extremity muscle strength, body mass index, and depression. Univariable and multivariable regression analyses were used to compare phenotypes on clinical outcomes (pain and activity limitations), taking into account possible confounders.

RESULTS

Five phenotypes of knee OA patients were identified: "minimal joint disease phenotype," "strong muscle phenotype," "nonobese and weak muscle phenotype," "obese and weak muscle phenotype," and "depressive phenotype." The "depressive phenotype" and "obese and weak muscle phenotype" showed higher pain levels and more severe activity limitations than the other 3 phenotypes.

CONCLUSION

Five phenotypes based on clinically relevant patient characteristics can be identified in the heterogeneous population of knee OA patients. These phenotypes showed different clinical outcomes. Interventions may need to be tailored to these clinical phenotypes.

Osteoarthritis of the knee at 3.0 T: comparison of a quantitative and a semi-quantitative score for the assessment of the extent of cartilage lesion and bone marrow edema pattern in a 24-month longitudinal study

OBJECTIVE

To compare a semi-quantitative and a quantitative morphological score for assessment of early osteoarthritis (OA) evolution.

MATERIALS AND METHODS

3.0 T MRI of the knee was performed in 60 women, 30 with early OA (each 15 with Kellgren-Lawrence grade 2 and 3) and 30 age-matched controls at baseline and at 12 and 24 months. Pathological condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were also quantified using a previously introduced morphological quantitative score. These data were correlated with changes in clinical parameters and joint space width using generalized estimation equations (GEE).

RESULTS

At baseline, OA patients had significantly (p < 0.05) more and larger cartilage lesions and BMEP. During follow-up, cartilage lesions increased significantly (p < 0.05) in the patients compared with controls: WORMS showed progression only at the lateral patella, whereas the quantitative score revealed progression additionally at the trochlea and at the medial compartment. Both scores showed a significant (p < 0.05) increase in BMEP at the lateral femur in OA patients. In addition, quantitative scores of BMEP of the whole knee decreased significantly (p < 0.05) after 12 months and increased after 24 months in the patients, but showed an increase in controls at all follow-up examinations. Only weak correlations between structural imaging findings and clinical parameters were observed.

CONCLUSION

Quantitative assessment of cartilage lesions and BMEP is more sensitive to changes during the course of the disease than semi-quantitative scoring. However, structural imaging findings do not correlate well with the clinical progression of OA.

Evaluation of an Inter-Professional Educational Intervention to Improve the Use of Arthritis Best Practices in Primary Care

Objective.

To describe the evaluation of a community-based continuing health education program designed to improve the management of rheumatoid arthritis (RA) and osteoarthritis (OA), and to examine the results by discipline.

Methods.

The Getting a Grip on Arthritis©program was based on clinical practice guidelines adapted for the primary care environment (best practices). The program consisted of an accredited inter-professional workshop and 6 months of activities to reinforce the learning. Analyses compared best practice scores derived from responses to 3 standardized case scenarios (early and late RA; moderate knee OA) at baseline and 6 months post-workshop using the ACREU Primary Care Survey.

Results.

In total, 553 primary care providers (nurses/licensed practical nurses 30.9%, rehabilitation professionals 22.5%, physicians 22.5%, nurse practitioners 10.9%, other healthcare providers/non-clinical staff/students 13.1%) attended one of 27 workshops across Canada; 275 (49.7%) completed followup surveys. Best practice scores varied by discipline at baseline (p < 0.05) and improved for all 3 case scenarios, with nurse practitioners and rehabilitation therapists improving the most (p ≤ 0.05).

Conclusion.

Results suggest that inter-professional education may be an effective method for dissemination of guidelines and has potential to improve the delivery of arthritis care, particularly when nurse practitioners and rehabilitation therapists are involved in the care of patients.

One-year change in radiographic joint space width in patients with unilateral joint space narrowing: data from the Osteoarthritis Initiative

OBJECTIVE

To examine the rate of joint space width (JSW) loss in both knees of patients with unilateral medial joint space narrowing (JSN) at baseline.

METHODS

Cases were selected from a pool of 2,678 subjects enrolled in the Osteoarthritis Initiative cohort. Inclusion criteria for the present study were unilateral medial JSN, bilateral frequent knee pain, and body mass index (BMI) > or = 25 kg/m(2). Baseline and 1-year fixed flexion radiographs of both knees were read (blinded to time point) using an automated algorithm for minimum JSW and JSW at 4 fixed locations in the medial compartment.

RESULTS

Sixty-seven participants met the inclusion criteria: 43 women and 24 men, with mean +/- SD age 60 +/- 9 years and mean +/- SD BMI 31 +/- 4 kg/m(2). Thirty-seven subjects (55%) had > or = 1 definite tibiofemoral osteophyte. The average progression in no-JSN knees was comparable with that in JSN knees (approximately -0.2 mm/year). However, JSW change was more variable in no-JSN knees, resulting in standardized response means (SRMs; the mean/SD) of approximately -0.24 in no-JSN knees versus approximately -0.41 in JSN knees on average at the 4 fixed locations, and SRMs of -0.24 and -0.35, respectively, for minimum JSW. Young age and high BMI were associated with increased progression, especially in JSN knees.

CONCLUSION

JSN and no-JSN knees progressed at a comparable rate, but a wider distribution of JSW change in no-JSN knees resulted in a poorer sensitivity to change in these knees.

Comparing two low-energy diets for the treatment of knee osteoarthritis symptoms in obese patients: a pragmatic randomized clinical trial

OBJECTIVES

To evaluate in a prospective, randomized clinical trial (RCT), symptom response among obese knee osteoarthritis (OA) patients following a feasible, intensive weight-loss program for 16 weeks.

METHODS

Eligible patients were obese [body mass index (BMI)>30 kg/m(2)]; >50 years old, with primary knee OA. Participants were randomized to either a very-low-energy diet (VLED) or a low-energy diet (LED) (415 kcal/day and 810 kcal/day, respectively), using commercially available formula foods - only for the first 8 weeks, managed by dieticians. The 8 weeks were followed by an additional 8-week period of a hypo-energetic diet consisting of normal food plus meal replacements (1200 kcal/day). The primary endpoint was the number of patients responding according to the Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) responder criterion. The statistical analysis was based on a non-responder intention-to-treat (ITT) population (baseline observation carried forward).

RESULTS

One hundred and ninety two patients (155 (80.7%) females) with a mean age 62.5 years [standard deviation (SD) 6.4; range 50-78 years]; average BMI 37.3 (SD 4.8) were included. At 16 weeks, similar proportions of the VLED and LED groups, 59 (61.5%), and 63 (65.6%) patients, respectively, met the OMERACT-OARSI responder criteria, with no statistical significant difference between the groups (P=0.55). Combining the groups the pooled estimate was 64% meeting the responder criteria [95% confidence interval (CI) 57%, 70%]. There was an overall reduction in pain, corresponding to an average pain reduction on the visual analogue scale (VAS) of 11.1 (95%CI 13.6, 8.5) in the combined groups. At week 16 weight loss in the combined groups was 12.8 kg (95%CI: 11.84-13.66; P<0.001). 71% lost > or =10% body weight in both diet groups, with a pooled estimate of 74% (95%CI: 68-80%).

CONCLUSION

No clinically significant differences were found between the 415 kcal/day and 810 kcal/day diets. A 16-week formula-diet weight-loss program resulted in a fast and effective weight loss with very few adverse events resulting in a highly significant improvement in symptoms in overweight patients with knee OA.

What are the best markers for disease progression in osteoarthritis (OA)?

To be able to prevent progression of osteoarthritis, the knowledge of prognostic factors of this progression is important. If certain prognostic factors are modifiable, they may enhance our ability to reduce osteoarthritis progression. Even if these prognostic factors are not modifiable, they can still be used to identify high-risk groups, which may have implications for patient information and the perspective of medical treatment. Prognostic factors of progression are reviewed here, mainly for hip and knee osteoarthritis as most data available concern these localisations. Areas of further research are highlighted.

Trabecular morphometry by fractal signature analysis is a novel marker of osteoarthritis progression

OBJECTIVE

To evaluate the effectiveness of using subchondral bone texture observed on a radiograph taken at baseline to predict progression of knee osteoarthritis (OA) over a 3-year period.

METHODS

A total of 138 participants in the Prediction of Osteoarthritis Progression study were evaluated at baseline and after 3 years. Fractal signature analysis (FSA) of the medial subchondral tibial plateau was performed on fixed flexion radiographs of 248 nonreplaced knees, using a commercially available software tool. OA progression was defined as a change in joint space narrowing (JSN) or osteophyte formation of 1 grade according to a standardized knee atlas. Statistical analysis of fractal signatures was performed using a new model based on correlating the overall shape of a fractal dimension curve with radius.

RESULTS

Fractal signature of the medial tibial plateau at baseline was predictive of medial knee JSN progression (area under the curve [AUC] 0.75, of a receiver operating characteristic curve) but was not predictive of osteophyte formation or progression of JSN in the lateral compartment. Traditional covariates (age, sex, body mass index, knee pain), general bone mineral content, and joint space width at baseline were no more effective than random variables for predicting OA progression (AUC 0.52-0.58). The predictive model with maximum effectiveness combined fractal signature at baseline, knee alignment, traditional covariates, and bone mineral content (AUC 0.79).

CONCLUSION

We identified a prognostic marker of OA that is readily extracted from a plain radiograph using FSA. Although the method needs to be validated in a second cohort, our results indicate that the global shape approach to analyzing these data is a potentially efficient means of identifying individuals at risk of knee OA progression.

Walking shoes and laterally wedged orthoses in the clinical management of medial tibiofemoral osteoarthritis: a one-year prospective controlled trial

The purpose of the study was to examine the clinical efficacy of individually prescribed laterally wedged orthoses and walking shoes in the treatment of medial knee osteoarthritis using a prospective, single-blind, block-randomized controlled design. Sixty-six subjects (29 males, 37 females, mean age 62.4 years, mean BMI 33.0 kg/m(2)) were block-randomized to a lateral wedge (treatment) or neutral (control) orthotic group. Both groups were issued a standardized walking shoe for use with the orthoses. Primary outcome measures included the pain, stiffness, and functional limitations subscales of the Western Ontario and McMaster Universities index. Secondary outcome measures included the 6-minute walk distance and pain change, and stair negotiation time and pain change. A significant interaction (p=0.039) favoring the treatment group was observed for pain change during the 6-minute walk. The treatment group demonstrated significant improvements at both 1 month (p<0.001) and 1 year (p<0.001) compared to baseline. The control group only demonstrated significant improvements at 1 year (p=0.017). No other interactions were observed. Both groups were improved at each follow-up in the WOMAC subscales for pain (p<0.001), stiffness (p<0.001), and physical function (p<0.001). Both groups also improved in 6-minute walk test distance (p<0.001), stair negotiation test time (p=0.004), and stair negotiation test pain change (p<0.001). The results suggest that both neutral and laterally wedged orthoses may be beneficial in the management of medial knee osteoarthritis when used with walking shoes. However, the addition of lateral wedging was associated with early improvements in 6-minute walk test pain change not seen in the control group.

Serum protein signatures detect early radiographic osteoarthritis

OBJECTIVE

To test the hypothesis that early knee and hand osteoarthritis (OA) development is characterized by detectable changes in serum proteins relevant to inflammation, cell growth, activation, and metabolism several years before OA becomes radiographically evident.

METHODS

Using microarray platforms that simultaneously test 169 proteins relevant to inflammation, cell growth, activation and metabolism, we conducted a case-control study nested within the Baltimore Longitudinal Study of Aging (BLSA). Subjects included 22 incident cases of OA and 66 age-, sex- and body mass index (BMI)-matched controls. Serum samples tested were obtained at the time of radiographic classification as either case or control, and up to 10 years earlier at a time when all participants were free of radiographic OA. Proteins with mean signal intensities fourfold higher than background were compared between cases and controls using multivariate techniques.

RESULTS

Sixteen proteins were different between OA cases compared to controls. Four of these proteins [matrix metalloproteinase (MMP)-7, interleukin (IL)-15, plasminogen activator inhibitor (PAI)-1 and soluble vascular adhesion protein (sVAP)-1] were already different in samples obtained 10 years before radiographic classification and remained different at the time of diagnosis. Six additional proteins were only associated with subsequent OA development and not with established OA.

CONCLUSIONS

Changes in serum proteins implicated in matrix degradation, cell activation, inflammation and bone collagen degradation products accompany early OA development and can precede radiographic detection by several years.

Risk factors in familial osteoarthritis: the GARP sibling study

PURPOSE

To investigate the association between systemic and local risk factors and familial osteoarthritis (OA) at multiple sites.

METHODS

Patients and their siblings had primary OA at multiple sites at middle age. OA diagnosis followed the American College of Rheumatology criteria. We recruited 345 controls (mean age 57 years (range 40-76), 64% women) by random sampling from the population by telephone and collected all data by questionnaires. Odds ratios (ORs) were adjusted for sex, age and body mass index (BMI) (kg/m(2)), 95% confidence intervals (CIs95) were computed using robust standard errors with the intra-family effect taken into account.

RESULTS

Three hundred and eighty-two patients (mean age 60 years [range 43-79]), 82% women had OA in the spine (80%), hands (72%), knees (34%) and hips (24%). In women, an association of familial OA with a young age at natural menopause (<45 years), OR=2.6 (CI95 1.5-4.5) was found. Physically demanding jobs led to an increased risk of familial OA in men: OR=2.6 (CI95 1.3-5.3). Familial OA was more prevalent in individuals with a BMI>30, OR=2.0 (CI95 1.3-3.2) compared to a BMI of <25. Taller persons had a lower risk of familial OA, OR=0.33 (0.1-0.8) in the height category >180 cm relative to a height of <160 cm. A history of meniscectomy, increased the risk of familial OA at multiple sites with knee involvement, OR=6.2 (CI95 3.0-12.7).

CONCLUSIONS

Systemic and local risk factors play a role in the etiology of familial OA at multiple sites.

Rates of medial tibiofemoral joint space narrowing in osteoarthritis studies consistent despite methodological differences

RATIONALE

Minimum tibiofemoral joint space width in the medial compartment (JSW) is the most well-established structural outcome measure for osteoarthritis (OA) of the knee. Its usefulness as a measure of therapeutic effectiveness in short-term studies is limited by the rate and variability of joint space narrowing (JSN) in the OA population. Microfocal radiography has been shown to improve reproducibility of JSW measurement compared to standard radiography, but measurement of magnification from microfocal knee films has been problematic, and JSN is yet to be investigated in a longitudinal microfocal study.

OBJECTIVE

To establish the effect on JSW reproducibility of a new method of magnification measurement in microfocal radiographs. To report on and compare rates of medial tibiofemoral JSN and their variations in the placebo arms of microfocal and standard radiographic clinical trials in OA, using fluoroscopic semi-flexed (SF) knee positioning. To place in the context of published estimates of rates of JSN from comparable studies.

METHODS

Using microfocal radiography, 36 patients were followed at a single centre for 2 years. Using standard radiography, 86 patients were followed for 1 year at a single centre, and 549 for 2 years in a multi-centre international study. Computerised JSW measurement was undertaken using enhanced and automated versions of existing algorithms. Rates of JSN were examined in the context of a review of published rates of JSN using a variety of techniques.

RESULTS

Reproducibility of JSW measurement from microfocal radiographs was improved by the new magnification measurement. Rates of JSN were similar across the studies, but more variable when using standard radiography. The rates of JSN were also consistent with those from previously published investigations; all estimates since 2000, bar one, being consistent with the value 0.05 mm/year.

CONCLUSION

Microfocal radiography using the new method lowered the variability of the rate of JSN, but the high cost and low availability of microfocal equipment remains a barrier to its more widespread use. The consistently low but highly variable rates of JSN seen in the review suggest that continued attempts to improve radiographic and mensural techniques are unlikely to significantly reduce required sample sizes.

Basic fibroblast growth factor stimulates matrix metalloproteinase-13 via the molecular cross-talk between the mitogen-activated protein kinases and protein kinase Cdelta pathways in human adult articular chondrocytes

Excessive release of basic fibroblast growth factor (bFGF) during loading and/or injury of the cartilage matrix may contribute to the onset or progression of osteoarthritis. This pathological role may be related to the ability of bFGF to decrease proteoglycan synthesis and to antagonize the activity of anabolic growth factors in cartilage such as insulin-like growth factor-1 and bone morphogenetic protein 7 (BMP7 or OP-1). Matrix metalloproteinase-13 (MMP-13), a catabolic cartilage-degrading enzyme, is dramatically up-regulated by inflammatory cytokines or by fibronectin fragments in articular chondrocytes. In this study, we investigated MMP-13 production by bFGF using human articular chondrocytes. Endogenous concentration of bFGF in synovial fluids collected from arthritis patients and asymptomatic subjects showed a good linear correlation with the endogenous levels of MMP-13. bFGF stimulation of MMP-13 was mediated at the transcriptional level and, at least in part, by stimulation of interleukin-1 production. Also, our findings suggest that bFGF stimulation of MMP-13 required the activation of multiple MAPKs (ERK, p38, and JNK) by bFGF, and more importantly, bFGF activation of protein kinase C (PKC) delta played a key role in the MMP-13 stimulation. Indeed, PKCdelta is the only isoform associated with MMP-13 stimulation among the PKC isoforms tested. PKCdelta controls the bFGF response by regulating multiple MAPK pathways. Our results suggest that PKCdelta activation is a principal rate-limiting event in the bFGF-dependent stimulation of MMP-13 in human adult articular chondrocytes. We propose that deregulation of cross-talk between MAPK and PKCdelta signaling may contribute to the etiology of osteoarthritis in human patients.

Prognostic factors of progression of osteoarthritis of the knee: A systematic review of observational studies

OBJECTIVE

To provide an overview of prognostic factors of knee osteoarthritis (OA) progression.

METHODS

We searched Medline and Embase up to December 2003 according to a specified search strategy (keywords for disease, location, and study design). Studies that fulfilled predefined criteria were assessed for methodologic quality. Study characteristics and associations were extracted and the results were summarized according to a best evidence synthesis.

RESULTS

Of the 1,004 studies found, 37 met the inclusion criteria. Methodologic quality was assessed and only high-quality studies were included (n = 36). The best evidence synthesis yielded strong evidence that hyaluronic acid serum levels and generalized OA are predictive for progression of knee OA. Sex, knee pain, radiologic severity, knee injury, quadriceps strength, and regular sport activities were not predictive. Conflicting evidence for associations was found for several factors including body mass index and age. Limited evidence for an association with progression of knee OA was found for several factors, including the alignment (varus/valgus) of the joint. Limited evidence for no association with progression of OA was also found for several factors, including meniscectomy, several markers of bone or cartilage turnover, and the clinical diagnosis of localized OA.

CONCLUSION

Generalized OA and level of hyaluronic acid seem to be associated with the radiologic progression of knee OA. Knee pain, radiologic severity at baseline, sex, quadriceps strength, knee injury, and regular sport activities seem not to be related. For other factors, the evidence was limited or conflicting.

Risedronate decreases biochemical markers of cartilage degradation but does not decrease symptoms or slow radiographic progression in patients with medial compartment osteoarthritis of the knee: results of the two-year multinational knee osteoarthritis structural arthritis study

OBJECTIVE

Bisphosphonates have slowed the progression of osteoarthritis (OA) in animal models and have decreased pain in states of high bone turnover. The Knee OA Structural Arthritis (KOSTAR) study, which is the largest study to date investigating a potential structure-modifying OA drug, tested the efficacy of risedronate in providing symptom relief and slowing disease progression in patients with knee OA.

METHODS

The study group comprised 2,483 patients with medial compartment knee OA and 2-4 mm of joint space width (JSW), as determined using fluoroscopically positioned, semiflexed-view radiography. Patients were enrolled in 2 parallel 2-year studies in North America and the European Union. These studies evaluated the efficacy of risedronate at dosages of 5 mg/day, 15 mg/day, 35 mg/week (in Europe), and 50 mg/week (in North America) compared with placebo in reducing signs and symptoms, as measured by the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and patient global assessment (PGA) scores, and in slowing radiographic progression.

RESULTS

A reduction of approximately 20% in signs and symptoms, as measured by WOMAC subscales and PGA scores, was observed in all groups, with no treatment effect of risedronate demonstrated. Risedronate did not significantly reduce radiographic progression as measured by decreased JSW or using a dichotomous definition of progression (joint space loss of >or=0.6 mm). Thirteen percent of patients receiving placebo demonstrated significant disease progression over 2 years. A dose-dependent reduction in the level of C-terminal crosslinking telopeptide of type II collagen, a cartilage degradation marker associated with progressive OA, was seen in patients who received risedronate. No increase in the number of adverse events was demonstrated for risedronate compared with placebo.

CONCLUSION

Although risedronate (compared with placebo) did not improve signs or symptoms of OA, nor did it alter progression of OA, a reduction in the level of a marker of cartilage degradation was observed. A sustained clinically relevant improvement in signs and symptoms was observed in all treatment and placebo groups.

MRI for development of disease-modifying osteoarthritis drugs

MRI has advantages as an imaging modality for drug development through its potential to provide information regarding localized morphological parameters, in addition to metrics of the structural and molecular state of cartilage. These metrics have the potential to provide earlier indications of pathology and may progress more rapidly than radiographic measures. These combined scans of localized morphology and matrix parameters will most likely provide a fuller assessment of cartilage state and will improve the cost and practicality of an overall evaluation of cartilage status by MRI. In the first part of this review, the relevant parameters are presented in terms of the information content they might provide in the drug development process. In the second part, applications of the MRI parameters in preclinical and clinical drug development are presented.

Musculoskeletal disorders associated with obesity: a biomechanical perspective

Despite the multifactorial nature of musculoskeletal disease, obesity consistently emerges as a key and potentially modifiable risk factor in the onset and progression of musculoskeletal conditions of the hip, knee, ankle, foot and shoulder. To date, the majority of research has focused on the impact of obesity on bone and joint disorders, such as the risk of fracture and osteoarthritis. However, emerging evidence indicates that obesity may also have a profound effect on soft-tissue structures, such as tendon, fascia and cartilage. Although the mechanism remains unclear, the functional and structural limitations imposed by the additional loading of the locomotor system in obesity have been almost universally accepted to produce aberrant mechanics during locomotor tasks, thereby unduly raising stress within connective-tissue structures and the potential for musculoskeletal injury. While such mechanical theories abound, there is surprisingly little scientific evidence directly linking musculoskeletal injury to altered biomechanics in the obese. For the most part, even the biomechanical effects of obesity on the locomotor system remain unknown. Given the global increase in obesity and the rapid rise in musculoskeletal disorders, there is a need to determine the physical consequences of continued repetitive loading of major structures of the locomotor system in the obese and to establish how obesity may interact with other factors to potentially increase the risk of musculoskeletal disease.

Body mass index associated with onset and progression of osteoarthritis of the knee but not of the hip: the Rotterdam Study

OBJECTIVE

To investigate the relationship between body mass index (BMI) and the incidence and progression of radiological knee as well as of radiological hip osteoarthritis.

DESIGN

Cohort study.

SETTING

Population based.

PARTICIPANTS

3585 people aged > or =55 years were selected from the Rotterdam Study, on the basis of the availability of radiographs of baseline and follow-up.

MAIN OUTCOME MEASURES

Incidence of knee or hip osteoarthritis was defined as minimally grade 2 at follow-up and grade 0 or 1 at baseline. The progression of osteoarthritis was defined as a decrease in joint space width.

METHODS

x Rays of the knee and hip at baseline and follow-up (mean follow-up of 6.6 years) were evaluated. BMI was measured at baseline.

RESULTS

A high BMI (>27 kg/m(2)) at baseline was associated with incident knee osteoarthritis (odds ratio (OR) 3.3), but not with incident hip osteoarthritis. A high BMI was also associated with progression of knee osteoarthritis (OR 3.2). For the hip, a significant association between progression of osteoarthritis and BMI was not found.

CONCLUSION

On the basis of these results, we conclude that BMI is associated with the incidence and progression of knee osteoarthritis. Furthermore, it seems that BMI is not associated with the incidence and progression of hip osteoarthritis.