Design, Development and Validation of a Knee Brace to Standardize the US Imaging Evaluation of Knee Osteoarthritis

Objective: A repeatable and reliable follow-up of knee injuries would be desirable to prevent delayed diagnosis and to monitor the efficacy of the applied treatment over time. Ultrasound (US) techniques are an attractive option to this purpose, since they are safe, low-cost and non-invasive. However, its use in the clinical practice is limited by the high dependency on the operator’s experience. Hence, the objective of this study is to provide a standardization of the US image acquisition process for knee osteoarthritis (OA) allowing an extended clinical use of US technologies in this domain. Methods: Clinical specifications were provided by expert musculoskeletal radiologists thus identifying the subject poses and the US probe positions needed to evaluate the cartilage structure, signs of synovitis and joint effusion. Such considerations were used to derive the technical requirements needed for the development of a wearable brace equipped with specific openings to guide the correct placement of the probe. The feasibility of the developed wearable brace was tested on three healthy volunteers, which were asked to acquire informative US images, similar to the reference images performed by the musculoskeletal radiologist. Results: Thanks to the knee brace, the untrained subjects were able to self-acquire informative B-mode images comparable to the corresponding images acquired by an expert clinician. Discussion/Conclusion: The use of a knee brace intended for knee OA US diagnosis demonstrated the possibility to standardize the acquisition protocol and make its application achievable also for untrained subjects, representing a key step toward tele-ultrasonography.

A Novel Mutation of the KLK6 Gene in a Family With Knee Osteoarthritis

To investigate the correlation between gene mutation and knee osteoarthritis (KOA), a whole-exome sequencing (WES) was applied to analyze blood samples of four KOA patients and two normal subjects in a family. Gene mutations were identified by gene-trapping and high-throughput sequencing analysis across the differences between the patients and normal subjects. The interactive gene network analysis on the retrieval of interacting genes (STRING) database and the KOA-related genes expression data sets was performed. A possibly detrimental and nonsynonymous mutation at the kallikrein-related peptidase 6 (KLK6) gene (rs201586262, c. C80A, P27H) was identified and attracted our attention. KLK6 belongs to the kallikrein family of serine proteases and its serum level is known as a prevalent biomarker in inflammatory and malignant diseases. KLK6 expresses in the extracellular compartment for matrix degradation, highlighting that KLK6 plays a role in the pathogenesis of KOA. By using the gene databases, the KOA-related genes were mined after de-duplication and IL6 was selected as the most relevant gene through interactive analysis of protein-protein interaction (PPI) network. The data suggested that KLK6 gene mutation and the related expression alteration of IL6 gene might determine the occurrence of hereditary KOA. The is the first study discovering the gene mutation of KLK6 as a factor of pathogenesis of KOA, especially the hereditary KOA.

State of art in intra-articular hip injections of different medications for osteoarthritis: a systematic review

BACKGROUND

Intra-articular hip injections for osteoarthritis represent a useful instrument to reduce pain and disability in the common clinical practice. Several medications can be injected locally with different level of evidence-based efficacy.

OBJECTIVE

The objective of this systematic review is to investigate the effectiveness of intra-articular injections of different medications or substances for the pain treatment and the management of disability in subjects affected by hip osteoarthritis.

METHODS

Two reviewers selected independently randomised controlled trials published in the last 10 years, using PubMed and Scopus databases. The risk of bias was evaluated with Cochrane library assessment tool.

RESULTS

12 randomised controlled trials have been selected. We found 8 papers comparing hyaluronic acid with platelet rich plasma, with corticosteroids and with saline solution; 1 paper compares two types of hyaluronic acid with different molecular weights; 3 papers study the effects of corticosteroids alone or compared to ketorolac or saline solution.

CONCLUSIONS

The studies reviewed were heterogeneous regarding sample size, level of osteoarthritis, evaluated with Kellegren-Lawrence score, medications used and follow up timings. However, we have observed that intra-articular injections of platelet-rich plasma seem to decrease pain at short term and disability at long term, in patients affected by hip osteoarthritis better than hyaluronic acid. The association of hyaluronic acid and corticosteroids could give better results compared to hyaluronic acid alone, while the use of intra-articular ketorolac and saline solution requires more studies.

Platelet-rich plasma injections for hip osteoarthritis: a review of the evidence

Osteoarthritis is a significant cause of chronic pain in the elderly population with hip osteoarthritis as one of the main causes of functional disability and joint pain in adults older than 55 years. Recently, platelet rich plasma (PRP) injections have been introduced for treatment of osteoarthritis. The aim of this systematic review is to assess its effectiveness in the management of hip osteoarthritis. We performed a search of the literature for published prospective studies that assessed the effectiveness of PRP injections in the treatment of hip osteoarthritis, with a minimum follow-up of 3 months. Primary outcome measures were WOMAC and VAS scores. Five trials were identified with 185 patients undergoing treatment with ultrasound-guided intra-articular injections of PRP, compared with patients treated with hyaluronic acid alone (n = 148) or hyaluronic acid combined with PRP (n = 31) in one study. PRP was shown to improve patient outcome scores at follow-up at 6 and 12 months; however, there was no significant difference seen between patients treated with PRP or hyaluronic acid alone. Following this systematic review, we cannot currently recommend the use of intra-articular injections of PRP for the treatment of hip OA. Given that intra-articular steroid injections are the only such injection recommended by international guidelines for the treatment of hip OA, further studies comparing PRP to steroid would be of benefit to determine the value of PRP injections in hip OA.

A novel therapeutic strategy for cartilage diseases based on lipid nanoparticle-RNAi delivery system

Background

Cartilage degeneration affects millions of people but preventing its degeneration is a big challenge. Although RNA interference (RNAi) has been used in human trials via silencing specific genes, the cartilage RNAi has not been possible to date because the cartilage is an avascular and very dense tissue with very low permeability.

Purpose

The objective of this study was to develop and validate a novel lipid nanoparticle (LNP)-siRNA delivery system that can prevent cartilage degeneration by knocking down specific genes.

Methods

LNP transfection efficiency was evaluated in vitro and ex vivo. Indian Hedgehog (Ihh) has been correlated with cartilage degeneration. The in vivo effects of LNP-Ihh siRNA complexes on cartilage degeneration were evaluated in a rat model of surgery-induced osteoarthritis (OA).

Results

In vitro, 100% of chondrocytes were transfected with siRNA in the LNP-siRNA group. In accordance with the cell culture results, red positive signals could be detected even in the deep layer of cartilage tissue cultures treated by LNP-beacon. In vivo data showed that LNP is specific for cartilage, since positive signals were detected by fluorescence molecular tomography and confocal microscopy in joint cartilage injected with LNP-beacon, but not on the surface of the synovium. In the rat model of OA, intraarticular injection of LNP-Ihh siRNA attenuated OA progression, and PCR results showed LNP-Ihh siRNA exerted a positive impact on anabolic metabolism and negative impact on catabolic metabolism.

Conclusion

This study demonstrates that our LNP-RNAi delivery system has a significantly chondroprotective effect that attenuates cartilage degeneration and holds great promise as a powerful tool for treatment of cartilage diseases by knocking down specific genes.

Myostatin serum concentrations are correlated with the severity of knee osteoarthritis

OBJECTIVE

Myostatin, a member of the transforming growth factor-β family, contributes to joint deterioration in mice. Thus, we aimed to assess the correlation of myostatin concentrations with the presence and severity of knee osteoarthritis (OA).

MATERIAL AND METHODS

We determined serum and synovial fluid (SF) myostatin concentrations in a population of 184 patients with knee OA and 109 healthy controls.

RESULTS

The knee OA group presented with higher serum myostatin concentrations than the controls. Knee OA patients with KL grade 4 showed higher serum and SF myostatin concentrations compared with those with KL grade 2 and 3. Knee OA patients with KL grade 3 had higher serum and SF myostatin concentrations compared with those with KL grade 2. Serum and SF myostatin concentrations were significantly correlated with KL grading.

CONCLUSION

Serum and SF myostatin concentrations were correlated with the presence and severity of knee OA.

Plasma and Synovial Fluid CXCL12 Levels Are Correlated With Disease Severity in Patients With Knee Osteoarthritis

BACKGROUND

The aim is to determine whether CXC chemokine ligand-12 (CXCL12) levels in plasma and synovial fluid (SF) of patients with knee osteoarthritis (OA) are correlated with the disease severity. In addition, we set out to investigate whether a peripheral blood test can avoid aspirating patients to determine CXCL12 levels.

METHODS

This study consisted of 244 patients with knee OA and 244 age- and gender-matched healthy controls. Osteoarthritis progression was classified based on Kellgren-Lawrence (KL) by evaluating radiographic changes observed in anteroposterior knee radiography. The CXCL12 levels in the plasma and SF were measured by a quantitative sandwich enzyme-linked immunosorbent assay.

RESULTS

Plasma CXCL12 levels were higher in OA patients as compared with controls (P < .0001). There was a positive correlation between levels of CXCL12 and grade (P < .0001). Base on the receiver operating characteristic curve, the optimal cutoff value of plasma CXCL12 levels as an indicator for screening of OA was estimated to be 5.5 ng/mL, which yielded a sensitivity of 78.4% and a specificity of 80.2%, with the area under the curve at 0.850 (95% confidence interval [CI], 0.816-0.889; P < .0001). In multivariate analysis, there was an increased risk of active OA associated with plasma CXCL12 levels ≥10.5 ng/mL (odds ratio, 6.76; 95% CI, 3.88-12.53; P < .0001) after adjusting for possible confounders. Similarly, there was an increased risk of active OA associated with SF CXCL12 levels ≥15.0 ng/mL (odds ratio, 8.45; 95% CI, 3.23-18.22; P < .0001) after adjusting for possible confounders.

CONCLUSION

The CXCL12 levels in the plasma and SF may serve as effective biomarkers for the severity of OA.

Analysis of distribution and severity of inflammation in patients with osteoarthitis compared to rheumatoid arthritis by ICG-enhanced fluorescence optical imaging and musculoskeletal ultrasound: a pilot study

Background

In rheumatoid arthritis (RA), hand synovitis appears especially in wrist, metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. In hand osteoarthritis (OA), potential inflammatory changes are mainly present in PIP and distal interphalangeal (DIP) joints. Joint inflammation can be visualised by fluorescence optical imaging (FOI) and musculoskeletal ultrasound (US).

Objective

Comparison of the amount and distribution of inflammatory signs in wrist and finger joints of the clinically dominant hand in patients with OA and RA by FOI and gray-scale (GSUS) and power Doppler US (PDUS).

Methods

FOI and GSUS/PDUS were performed in 1.170 joints (wrists, MCP, PIP, DIP) in 90 patients (67 RA, 23 OA). Joint inflammation was graded by a semiquantitative score (0–3) for each imaging method.

Results

GSUS/PDUS showed wrist and MCP joints mostly affected in RA. DIP joints were graded higher in OA. In FOI, RA and OA featured inflammatory changes in the respective joint groups depending on the phase of fluorescence dye flooding.

Conclusions

US and FOI detected inflammation in both RA and OA highlighting the inflammatory component in the course of OA. The different inflammatory patterns and various shapes of fluorescence enhancement in FOI may offer opportunities to distinguish and determine the inflammatory status in both diseases.

Global ultrasound assessment of structural lesions in osteoarthritis: a reliability study by the OMERACT ultrasonography group on scoring cartilage and osteophytes in finger joints

OBJECTIVE

Ultrasonography is sensitive for the evaluation of cartilage pathology and degree of osteophytes in patients with hand osteoarthritis (OA). High consistency of assessments is essential, and the OMERACT (Outcome Measures in Rheumatology) ultrasonography group took the initiative to explore the reliability of a global ultrasonography score in patients with hand OA using semiquantitative ultrasonography score of cartilage and osteophytes in finger joints.

METHODS

Ten patients with hand OA were examined by 10 experienced sonographers over the course of two days. Semiquantitative scoring (0-3) was performed on osteophytes (carpo-metacarpal 1, metacarpo-phalangeal (MCP) 1-5, proximal interphalangeal 1-5 and distal interphalangeal 2-5 joints bilaterally with an ultrasonography atlas as reference) and cartilage pathology (MCP 2-5 bilaterally). A web-based exercise on static cartilage images was performed a month later. Reliability was assessed by use of weighted κ analyses.

RESULTS

Osteophyte scores were evenly distributed, and the intraobserver and interobserver reliabilities were substantial to excellent (κ range 0.68-0.89 and mean κ 0.65 (day 1) and 0.67 (day 2), respectively). Cartilage scores were unevenly distributed, and the intraobserver and interobserver reliability was fair to moderate (κ range 0.46-0.66 and mean κ 0.39 (day 1) and 0.33 (day 2), respectively). The web-based exercise showed acceptable agreement for cartilage being normal (κ 0.47) or with complete loss (κ 0.68), but poor for the intermediate scores (κ 0.22-0.30).

CONCLUSIONS

Use of the present semiquantitative ultrasonography scoring system for cartilage pathology in hand OA is not recommended (while normal or total loss of cartilage may be assessed). However, the OMERACT ultrasonography group will endorse the use of semiquantitative scoring of osteophytes with the ultrasonography atlas as reference.

Osteoarthritis year in review 2014: imaging

PURPOSE

This narrative review covers original publications related to imaging in osteoarthritis (OA) published in English between April 2013 and March 2014. In vitro data, animal studies and studies with less than 20 observations were not included.

METHODS

To extract relevant studies, an extensive PubMed database search was performed based on, but not limited to the query terms "Osteoarthritis" in combination with "MRI", "Imaging", "Radiography", "Ultrasound", "Computed Tomography" and "Nuclear Medicine". Publications were sorted according to relevance based on potential impact to the OA research community with the overarching goal of a balanced overview covering all aspects of imaging. Focus was on publications in high impact special interest journals. The literature will be presented in a methodological fashion covering radiography, ultrasound, compositional and morphologic Magnetic resonance imaging (MRI), and from an anatomic perspective including bone, muscle, meniscus and synovitis.

RESULTS AND CONCLUSIONS

Imaging research in OA in the last year was characterized by a strong focus on MRI-based studies dealing with epidemiological and methodological aspects of the disease. Ultrastructural tissue assessment specifically of cartilage and meniscus using compositional MRI is evolving further. Additional subsets of the large publicly available Osteoarthritis Initiative (OAI) MRI dataset are being analyzed at present and have been published with muscle analyses coming increasingly into the focus of the community. Bone parameters were evaluated using varying technology and a persistent interest in inflammatory disease manifestations has been noted. Other modalities than MRI have been less explored. To date most OA imaging research is still focused on the knee joint.

Construction and verification of the targeted uPA-shRNA lentiviral vector and evaluation of the transfection and silencing rate

Urokinase-type plasminogen activator (uPA) receptors, which are released by the synovial tissue, are responsible for the activation of cartilage-breakdown proteases and play critical roles in cartilage degradation during the progression of osteoarthritis (OA). RNA interference (RNAi) technology has emerged as a potent tool to generate cellular knockdown phenotypes of a desired gene. The aims of the present study were to investigate the effect of siRNA specific to the uPA gene on chondrocytes and to investigate the possible mechanisms of OA. Firstly, four types of small hairpin RNA (shRNA) sequence (P1, P2, P3 and P4) were obtained from the targeted uPA gene of the New Zealand rabbit, based on siRNA theory. The sequences were designed, constructed and subjected to restriction enzyme digestion, transformation, polymerase chain reaction (PCR) identification, positive clone sequencing and lentivirus packaging. Secondly, primary culturing cartilage cells from the New Zealand rabbit were transfected with P1, P2, P3 or P4 to observe the transfection rate under a fluorescence microscope. The mRNA expression levels of uPA were analyzed in cartilage cells using quantitative PCR, while protein expression levels were analyzed in the cartilage cells using western blot technology. Four types of uPA-shRNA lentiviral vectors were constructed successfully, which were all able to be transfected into the primary culturing cartilage cells. The transfection rate was as high as 85% when the multiplicity of infection was 100, which demonstrated that P1, P2, P3 and P4 were all capable of inhibiting the mRNA and protein expression of uPA in cartilage cells. In addition, among the four sequences, the P2 sequence exhibited the highest silencing rate of 70%. Statistical significance (P<0.05) was observed when analyzing the silencing rate of P2 compared to the other three groups. The most efficient targeted uPA-shRNA sequence was identified following screening. The results strongly verified that siRNA lentiviral vectors can be transfected into cartilage cells to further inhibit the expression of the uPA gene efficiently and steadily. Thus, the results provide the foundation for further research on the role of uPA in the pathogenesis of OA.

Evaluation of the effect of D-002, a mixture of beeswax alcohols, on osteoarthritis symptoms

BACKGROUND/AIMS

Nonsteroidal anti-inflammatory drugs relieve osteoarthritis (OA) symptoms but cause adverse effects. D-002, a mixture of beeswax alcohols, is effective against experimental OA. A pilot study found that D-002 (50 mg/day) for 8 weeks improves OA symptoms. The aim of this study was to investigate the effects of D-002 (50 to 100 mg/day) administered for 6 weeks on OA symptoms.

METHODS

Patients with OA symptoms were double-blindly randomized to D-002 (50 mg) or placebo for 6 weeks. Symptoms were assessed by the Western Ontario and McMaster Individual Osteoarthritis Index (WOMAC) and the visual analog scale (VAS) scores. Patients without symptom improvement at week 3 were titrated to two daily tablets. The primary outcome was the total WOMAC score. WOMAC pain, joint stiffness and physical function scores, VAS score, and use of rescue medications were secondary outcomes.

RESULTS

All randomized patients (n = 60) completed the study, and 23 experienced dose titration (two in the D-002 and 21 in the placebo groups). At study completion, D-002 reduced total WOMAC (65.4%), pain (54.9%), joint stiffness (76.8%), and physical function (66.9%) WOMAC scores, and the VAS score (46.8%) versus placebo. These reductions were significant beginning in the second week, and became enhanced during the trial. The use of rescue medication by the D-002 (6/30) group was lower than that in the placebo (17/30) group. The treatment was well tolerated. Seven patients (two in the D-002 and five in the placebo group) reported adverse events.

CONCLUSIONS

These results indicate that D-002 (50 to 100 mg/day) for 6 weeks ameliorated arthritic symptoms and was well tolerated.

The single nucleotide polymorphism (SNP) of the estrogen receptor-β gene, rs1256049, is associated with knee osteoarthritis in Korean population

BACKGROUND

Estrogens affect articular cartilage metabolism via estrogen receptors (ER) in chondrocytes and are believed to play an important role in the pathophysiology of osteoarthritis (OA). The aim of this study is to determine whether the single nucleotide polymorphism (SNP) of the estrogen receptor-β (ER-β) is associated with an increased susceptibility to knee OA.

METHODS

The possible influence of the SNP of the ER-β was investigated in 286 OA patients and 294 healthy subjects as controls. A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay and a PCR-single strand conformation polymorphism (SSCP) assay were used to identify the Rsa polymorphism genotype among healthy controls and OA patients, respectively.

RESULTS

For rs1256049 (Rsa), frequencies of genotypes GG, GA, and AA were 49.0% (144/294), 43.5% (128/294), and 7.5% (22/294) in healthy controls, and 35.3% (101/286), 45.5% (130/286), and 19.2% (55/286) in OA patients. Frequencies of alleles G and A among healthy controls were 70.7% (416/588) and 29.3% (172/588); whereas those among OA patients were 58.0% (332/572) and 42.0% (240/572). Statistically significant differences in allele and genotype frequencies of rs1256049 were observed between OA patients and controls (P<0.0001). In particular, the risk of OA was significantly increased in carriers with the rs1256049A allele and rs1256049 AA homozygotes.

CONCLUSIONS

These results suggest a close association of rs1256049 ER-β polymorphisms with susceptibility to OA in the Korean population.

CLINICAL RELEVANCE

The rs1256049 polymorphism of the estrogen receptor-β gene can potentially be used to identify genetically high-risk subgroup of osteoarthritis in advance and to understand pathogenesis of osteoarthritis.