Pain in patients with equal radiographic grades of osteoarthritis in both knees: the value of gray scale ultrasound

Assessment of validity, reliability, and feasibility of OMERACT ultrasound knee osteoarthritis scores in Egyptian patients with primary knee osteoarthritis

BACKGROUND

Ultrasound (US) can evaluate all joint components affected by knee osteoarthritis (KOA); however, standardized scoring of US-detected pathology is needed to improve its diagnostic and monitoring capabilities.

OBJECTIVES

To examine the validity, reliability, and feasibility of the Outcome Measures in Rheumatology (OMERACT) ultrasound scoring for KOA, comparing with clinical and radiography measures, using predefined cutoff values.

METHODS

This cross-sectional study included 75 Egyptian patients with primary KOA. All patients had Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, bilateral knee radiography, and ultrasonography. Inter-observer reliability of ultrasound was evaluated in 30 knees by another newly trained operator.

RESULTS

Most of the OMERACT-US KOA scores showed significant associations with WOMAC clinical scores, except for femoral cartilage damage and effusion. The synovitis score was significantly associated with WOMAC-pain score (p-value 0.046), while medial meniscus extrusion (MME) and medial osteophytes were significantly associated with WOMAC-stiffness score (p-value 0.009 and 0.023, respectively). MME and synovitis were significantly associated with WOMAC-physical score (p-value 0.035 and 0.020, respectively). The ultrasound scores also showed a strong correlation with radiographic scoring. Inter-observer reliability ranged from moderate to excellent agreement (k = 0.58 to k = 0.83); it was highest for lateral osteophytes (k = 0.83), good agreement for synovitis (k = 0.72), any osteophytes (k = 0.71), damage of femoral cartilage (k = 0.70), and moderate agreement for medial osteophytes (k = 0.58) and MME (k = 0.59).

CONCLUSION

OMERACT-US scoring system for KOA demonstrated validity, reliability, and feasibility for evaluating both structural and inflammatory components. Using cutoff values improved the scoring reliability for osteophytes and MME. Key Points • OMERACT-US scores provide a valid assessment of inflammatory and structural components of knee osteoarthritis. • The following changes may improve the performance of the OMERACT-US scores. a. The binary score for effusion and synovial hypertrophy can be omitted, as they have no added value. b. A semi-quantitative grading for effusion may capture the impact of effusion on clinical outcomes. c. Added cutoff values to score medial meniscal extrusion, osteophytes, and pathological effusion improved the respective scores' reliability. d. Applying the updated OMERACT definition of synovitis. • OMERACT-US scores are reliable to be used with a newly trained operator, particularly when cutoff values are included, and proper training time is provided. • The OMERACT-US score is feasible to be used in clinical practice, as the time taken to perform was short, even for a newly trained operator.

Dynamics of the suprapatellar bursa during knee joint extension

PURPOSE

The suprapatellar bursa is located in the proximal deep layer of the patella and is thought to reduce tissue friction by changing from a single-membrane structure to a double-membrane structure during knee joint motion. However, the dynamics of the suprapatellar bursa have only been inferred from positional relationships, and the actual dynamics have not been confirmed.

METHODS

Dynamics of the suprapatellar bursa during knee joint motion were observed in eight knees of four Thiel-fixed cadavers and the angle at which the bursa begins to show a double membrane was revealed. The flexion angles of knee joints were measured when the double-membrane structure of the suprapatellar bursa began to appear during knee joint extension.

RESULTS

The suprapatellar bursa changes from a single membrane to a double-membrane structure at 91 ± 4° of flexion, when the knee joint is moved from a flexed position to an extended position.

CONCLUSION

The suprapatellar bursa may be involved in limitations to knee joint range of motion and pain at an angle of approximately 90°. Further studies are needed to verify whether the same dynamics are observed in living subjects.

The ultrasound assessment of osteoarthritis: the current status

Traditionally, osteoarthritis (OA) is diagnosed with the clinical examination supplemented by the conventional radiography (CR). In the research literature, the role of ultrasound (US) imaging in the diagnostics of OA has risen steadily during the last two decades. US imaging is cheap and globally widely available often already in primary healthcare. Here, we reviewed the most essential US literature focusing on OA diagnostics and progression prediction using the various search engines. Starting from the year 2000, our search provided 1 445 journal articles. After reviewing the abstracts, 89 articles were finally included. Most of the reviewed articles focused on the imaging of knee and hand OA, whereas only a minority dealt with the imaging of hip, ankle, midfoot, acromioclavicular, and temporomandibular joints. Overall, during the last 20 years, the use of US imaging for OA assessment has increased in the scientific literature. In knee and hand joints, US imaging has been reported to be a promising tool to evaluate OA changes. Furthermore, the reproducibility of US as well as its association to MRI findings are excellent. Importantly, US seems to even outperform CR in certain aspects, such as detection of osteophytes, joint inflammation, meniscus protrusion, and localized cartilage damage (especially at the medial femoral condyle and sulcus area). Based on the reviewed literature, US can be truly considered as a complementary tool to CR in the clinical setup for OA diagnostics. New technical developments may even enhance the diagnostic value of the US in the future.

The relationship between meniscal pathologies, cartilage loss, joint replacement and pain in knee osteoarthritis: a systematic review

OBJECTIVE

We conducted a systematic review in order to understand the relationship between imaging-visualised meniscus pathologies, hyaline cartilage, joint replacement and pain in knee osteoarthritis (OA).

DESIGN

A search of the Medline, Excerpta Medica database (EMBASE) and Cochrane library databases was performed for original publications reporting association between imaging-detected meniscal pathology (extrusion or tear/damage) and longitudinal and cross-sectional assessments of hyaline articular cartilage loss [assessed on magnetic resonance imaging (MRI)], incident joint replacement and pain (longitudinal and cross-sectional) in knee OA. Each association was qualitatively characterised by a synthesis of data from each analysis, based upon study design and quality scoring (including risk of bias assessment and adequacy of covariate adjustment using Cochrane recommended methodology).

RESULTS

In total 4,878 abstracts were screened and 82 publications were included (comprising 72 longitudinal analyses and 49 cross-sectional). Using high quality, well-adjusted data, meniscal extrusion and meniscal tear/damage were associated with longitudinal progression of cartilage loss, cross-sectional cartilage loss severity and joint replacement, independently of age, sex and body mass index (BMI). Medial and lateral meniscal tears were associated with cartilage loss when they occurred in the body and posterior horns, but not the anterior horns. There was a lack of high quality, well-adjusted meniscal pathology and pain publications and no clear independent association between meniscal extrusion or tear/damage with pain severity, progression in pain or incident frequent knee symptoms.

CONCLUSION

Meniscal features have strong associations with cartilage loss and joint replacement in knee OA, but weak associations with knee pain. Systematic review PROSPERO registration number: CRD 42020210910.

Intra-articular pressure characteristics of the knee joint: An exploratory study

Inflammation-predominant osteoarthritis is an important clinical type of osteoarthritis, with synovitis suggested as its distinct pathophysiology. We investigated whether the synovium's mechanical properties in knees differed by osteoarthritis and other clinical parameters through retrospectively analyzing intra-articular pressure-volume characteristics. We analyzed 60 knees that were administered intra-articular corticosteroids while undergoing pressure monitoring. McMurray's test, pain complaints at end-range knee flexion, Kellgren-Lawrence classification from standing anteroposterior radiographs, and suprapatellar effusion from ultrasound constituted clinical parameters. Pressure-volume profiles-phasic changes in pressure by volume infusion, the volume of Phase 1-the potential volume of the synovial space, the pressure at 45 ml infusion-intra-articular pressure at a standardized volume, and the slope of Phase 2-synovial stiffness were compared with clinical parameters. All graphs were biphasic. Knees with suprapatellar effusion or radiologically definite osteoarthritis (Kellgren-Lawrence grade ≥2), had a lower Phase 1 volume. Knees with definite radiographic osteoarthritis also showed higher pressures at 45 ml and Phase 2 slopes (171.11 ± 94.35 mmHg and 5.08 ± 3.07 mmHg/ml, respectively) than those without (101.88 ± 58.12 mmHg and 2.84 ± 1.27 mmHg/ml, respectively). The Phase 2 slope was higher for knees with positive provocative tests than in those with negative provocative tests, although not statistically significant. The synovium stretched earlier in knees with effusion or radiologically definite osteoarthritis. Intra-articular pressure and synovial stiffness were significantly higher in patients with radiologically definite osteoarthritis. The synovium's mechanical characteristics are altered by osteoarthritis of the knee joint. Intra-articular pressure characteristics could be utilized for synovial evaluation clinically.

Single Injection of Cross-Linked Hyaluronate in Knee Osteoarthritis: A 52-Week Double-Blind Randomized Controlled Trial

Background: to compare the 52-week effectiveness and safety between HYAJOINT Plus (HJP) and Durolane in knee osteoarthritis (OA) treatment. Methods: consecutive patients received a single injection of 3 mL HJP or Durolane. The primary outcome was a visual analog scale (VAS) pain measurement at 26 weeks post-injection. Secondary outcomes included other clinical, satisfaction, and safety assessments for 52 weeks. Results: 142 patients were equally randomized. At week 26, the HJP group had less VAS pain than the Durolane group (18.1 ± 9.5 versus 24.4 ± 14.0, p = 0.001). Both groups showed improvement in their VAS pain and stiffness scores, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and total scores for 52 weeks after injection (p < 0.001). However, the HJP group showed lower VAS pain and stiffness scores, reduced WOMAC pain and stiffness scores, a shorter Timed “Up & Go” (TUG) time, and a higher satisfaction score than the Durolane group for 39 weeks (p < 0.05). Only mild and self-limited adverse events occurred (40.8%). Conclusion: While a single injection of either HJP or Durolane is safe and effective for at least 52 weeks, HJP provided superior improvement in terms of VAS pain and stiffness scores, WOMAC pain and stiffness scores, and satisfaction score within 39 weeks of treatment.

Knee Cartilage and Subchondral Bone Evaluations by Magnetic Resonance Imaging Correlate with Histological Biomarkers in an Osteoarthritis Rabbit Model

OBJECTIVE

To evaluate pathological changes in cartilage and subchondral bone MRI biomarkers in a rabbit model of osteoarthritis (OA) and correlate these with histological variations.

DESIGN

Transection of the anterior cruciate ligament was performed on the right knee of eighteen 12-week-old New Zealand white rabbits to induce OA. 3-Tesla MR images were obtained from 18 healthy control knees (left) and 18 knees with OA (right). Imaging biomarkers included volume, thickness, T1 and T2* cartilage parametric maps, and several subchondral bone features: bone volume to total volume ratio, trabecular thickness, trabecular spacing, trabecular number (TbN), 2D and 3D fractal dimensions, and quality of trabecular score (QTS). Microscopic analysis of the lateral femoral condyles was set as the ground truth.

RESULTS

When healthy and osteoarthritic knees were compared, significant differences were seen in the T1 and T2* values of the femur and tibia cartilage and in the subchondral bone volume to total volume, TbN, and QTS of both the lateral and medial aspects of the femur and tibia. Histological findings revealed significant osteoarthritic changes between healthy and osteoarthritic knees in stain, structure, chondrocyte density, total score, and subchondral bone biomarker levels. A positive correlation was found between histological staining, structure, chondrocyte density, and total score variables in T1 and T2* cartilage biomarkers. A negative correlation was observed between histological subchondral bone variables and magnetic resonance D2D and QTS biomarkers.

CONCLUSION

Quantification of several cartilage and subchondral bone imaging biomarkers in a rabbit model of OA allows the detection of significant changes, which are correlated with histological findings.

Clinical significance and management of meniscal extrusion in different knee pathologies: a comprehensive review of the literature and treatment algorithm

The menisci are crescent-shaped, fibrocartilaginous structures that play a crucial role in the load transition and distribution of the contact forces along the tibiofemoral articulation. Meniscal extrusion (ME) is a radiological finding, especially in magnetic resonance imaging (MRI) scans, for which there has been growing interest in recent years. ME, in the coronary plane, is defined as the maximum distance of the most distal end of the meniscus from the border of the tibial plateau, where the tibial eminences are the most prominent, without taking into account the osteophytes. Although there is still controversy in the literature in respect of the optimal cutoff value, a threshold of 3 mm is considered significant. ME has no specific clinical finding or sign and it is encountered in many knee pathologies. It is associated with either rapidly progressive knee osteoarthritis or early onset of knee osteoarthritis and increased morbidity. In this review, we delineate the clinical significance of ME in various knee pathologies, as well as when, why and how it should be managed. To the best of our knowledge, this is the first study to elaborate on these topics.

Dynamic response of medial meniscus extrusion to the lateral wedge insole is correlated with immediate pain reduction in knee osteoarthritis patients: real-time ultrasonographic study

PURPOSE

To investigate the effect of lateral wedge insole (LWI) on medial meniscus extrusion (MME) observed during dynamic evaluation with ultrasound and its correlation with the alteration in knee pain in patients with knee osteoarthritis (OA).

METHODS

This cohort study included 25 participants with knee OA. The medial meniscus was imaged during walking in video mode using ultrasonography. The degree of increase in MME (ΔMME) was calculated as the difference in the value of the maximum and minimum MME. The intensity of knee pain was evaluated immediately after the walking trial using the visual analogue scale (VAS). These measurements were performed with and without the LWI. The participants were categorised into the responder group, which was identified by the constant reduction in the VAS, and the non-responder group.

RESULTS

MME, ΔMME, and knee pain during walking were significantly lower with the LWI than without the LWI (p < 0.01). The reduction in ΔMME with the LWI in the responder group was significantly higher than that in the non-responder group (p < 0.01).

CONCLUSIONS

Our findings showed that MME and knee pain during walking decreased with LWI use, especially in patients whose reduction in knee pain was characterised by inhibition in the increase in MME observed during dynamic evaluation with ultrasound.

Reliability and Convergent Construct Validity of Quantitative Ultrasound for Synovitis, Meniscal Extrusion, and Osteophyte in Knee Osteoarthritis With MRI

AIMS

To determine: 1) inter-rater reliability of quantitative measurements of ultrasound-detected synovitis, meniscal extrusion, and osteophytes; and 2) construct (convergent) validity via correlations and absolute agreements between ultrasound- and gold-standard magnetic resonance imaging (MRI)-outcomes in knee osteoarthritis.

METHODS

Dynamic ultrasound images for supra-patellar synovitis, meniscal extrusion, and osteophytes were acquired and quantified by a physician operator, musculoskeletal ultrasonographer, and medical student independently. On the same day, 3T MRI images were acquired. Effusion-synovitis, meniscal extrusion, and osteophytes were quantified on sagittal or coronal proton-density-weighted fat-suppressed noncontrast TSE sequences, respectively. Intra-class correlation coefficients (ICCs), Pearson's correlations (r), and Bland-Altman plots were used to analyze inter-rater reliability, and correlations, and agreements between the two imaging modalities.

RESULTS

Eighty-nine participants [48 females (53.9%)] with mean (standard deviation) age of 61.5 ± 6.9 years were included. The inter-rater reliability was excellent for osteophytes (ICC range = 0.90-0.96), meniscal extrusion (ICC range = 0.90-0.93), and synovitis (ICC range = 0.86-0.88). The correlations between ultrasound pathologies and their MRI counterparts were very strong (ICC range = 0.85-0.98) except for lateral meniscal extrusion [0.66 (95% CI, 0.52-0.76)]. Bland-Altman plots showed 0.01, 0.05, 0.10, 0.53, and 0.60 mm larger size in ultrasound medial tibial and medial femoral osteophytes, medial meniscal extrusions, synovitis, and lateral meniscal extrusions with 95% limits of agreements [±0.39, ±0.44, ±0.85, ±0.70, and ±0.90 (SDs)] than MRI measures, respectively. The lines of equality were within 95% CI of the mean differences (bias) only for medial osteophytes and medial meniscal extrusion.

CONCLUSION

The quantitative assessment of synovitis, meniscal extrusion, and osteophytes generally showed excellent inter-rater reliability and strong correlations with MRI-based measurements. Absolute agreement was strong for medial tibiofemoral pathologies.

Improved Joint Health Following Oral Administration of Glycosaminoglycans with Native Type II Collagen in a Rabbit Model of Osteoarthritis

Simple Summary

Osteoarthritis is an incurable chronic disease. For this reason, new therapies are constantly emerging to improve clinical signs and the quality of life of our pets. Chondroitin sulfate, glucosamine and hyaluronic acid have been proven effective and are the most widely used in many formulations. In the present study, adding native type II collagen to the combination of chondroitin sulfate, glucosamine and hyaluronic acid showed improvements on osteoarthritis progression in an experimental model of osteoarthritis induced by transection of the cranial cruciate ligament of the knee in New Zealand white rabbits. Disease progression was monitored at different time points using magnetic resonance imaging biomarkers, measurement of hyaluronic acid in synovial fluid, and macroscopic and microscopic evaluations of cartilage, synovial membrane and subchondral bone. Overall, our results showed that adding native type II collagen to a combination of glycosaminoglycans allows a significantly slower osteoarthritis progression, compared to glycosaminoglycans alone.

Abstract

A prospective, experimental, randomized, double blinded study was designed to evaluate the effects of glycosaminoglycans, with or without native type II collagen (NC), in an osteoarthritis model induced by cranial cruciate ligament transection. The following compounds were tested: chondroitin sulfate (CS), glucosamine hydrochloride (GlHCl), hyaluronic acid (HA) and NC. Fifty-four female 12-week-old New Zealand rabbits were classified into three groups: CTR (control–no treatment), CGH (CS + GlHCl + HA) and CGH-NC (CS + GlHCl + HA + NC). Each group was subdivided into three subgroups according to survival times of 24, 56 and 84 days. Over time, all rabbits developed degenerative changes associated with osteoarthritis. CGH-NC showed significantly improved values on macroscopic evaluation, compared to CTR and CGH. Microscopically, significantly better results were seen with CGH and CGH-NC, compared to CTR, and synovial membrane values were significantly better with CGH-NC compared to CGH. A significant improvement in magnetic resonance imaging biomarkers was also observed with CGH-NC in cartilage transversal relaxation time (T2) and subchondral bone D2D fractal dimension in the lateral condyle. In conclusion, our results show beneficial effects on joint health of CGH and CGH-NC and also supports that adding NC to CGH results in even greater efficacy.

The Neuroimmune Interplay in Joint Pain: The Role of Macrophages

Chronic pain associated with joint disorders, such as rheumatoid arthritis (RA), osteoarthritis (OA) and implant aseptic loosening (AL), is a highly debilitating symptom that impacts mobility and quality of life in affected patients. The neuroimmune crosstalk has been demonstrated to play a critical role in the onset and establishment of chronic pain conditions. Immune cells release cytokines and immune mediators that can activate and sensitize nociceptors evoking pain, through interaction with receptors in the sensory nerve terminals. On the other hand, sensory and sympathetic nerve fibers release neurotransmitters that bind to their specific receptor expressed on surface of immune cells, initiating an immunomodulatory role. Macrophages have been shown to be key players in the neuroimmune crosstalk. Moreover, macrophages constitute the dominant immune cell population in RA, OA and AL. Importantly, the targeting of macrophages can result in anti-nociceptive effects in chronic pain conditions. Therefore, the aim of this review is to discuss the nature and impact of the interaction between the inflammatory response and nerve fibers in these joint disorders regarding the genesis and maintenance of pain. The role of macrophages is highlighted. The alteration in the joint innervation pattern and the inflammatory response are also described. Additionally, the immunomodulatory role of sensory and sympathetic neurotransmitters is revised.

Association between knee inflammation and knee pain in patients with knee osteoarthritis: a systematic review

OBJECTIVE

To systematically review the literature on the relationship between markers of inflammation and pain in patients with knee osteoarthritis (OA).

METHODS

We searched MEDLINE, Web of Science and EMBASE databases from inception until June 2021. Eligible articles had to report on the association between inflammation (as measured by effusion, synovitis, baker's cysts, cytokines and C-reactive protein) and pain in patients with radiographic knee OA. Two reviewers independently performed a screening on title and abstracts, data extraction and risk of bias assessment using the Newcastle-Ottawa Scale (NOS). A best evidence synthesis was conducted for each inflammatory sign included in this review.

RESULTS

37 studies were included. Articles reported on the following measures: effusion or synovitis assessed via ultrasound (n = 9) or magnetic resonance imaging (MRI) (n = 17); baker's cyst (n = 3); cytokine concentrations (n = 11); and C-reactive protein levels (n = 4). The strength of the association between inflammation and pain does not exceed the moderate level (i.e., correlation coefficient values ranging from 0.19 to 0.61). Moderate levels of evidence were found for the association between synovitis (measured with ultrasound or contrast enhanced MRI) and pain. The levels of evidence between effusion (assessed via ultrasound), effusion/synovitis (assessed via non-contrast enhanced MRI), Baker's cyst, cytokines, C-reactive protein and pain were conflicting.

CONCLUSIONS

Different inflammatory markers are associated with pain but the correlation ranges from weak to moderate, and the quality of evidence from conflicting to moderate. Further research is needed to strengthen the level of evidence and to establish mechanisms.

A New Method to Develop the Primate Model of Knee Osteoarthritis With Focal Cartilage Defect

Objective: Osteoarthritis (OA) is a common degenerative joint disease, and animal models have proven pivotal in investigating this disease. This study aimed to develop a primate model of OA that may be more relevant to research studies on OA in humans.

Method: Twelve female rhesus macaques were randomly divided into three groups. Four animals were untreated (Control group); four were subjected to the modified Hulth method, involving cutting of the anterior and posterior cruciate ligaments, and transecting the meniscus (Hulth group); and four were subjected to the modified Hulth method combined with cartilage defect (MHCD group). Each primate was subjected to motor ability tests, and underwent arthroscopic, radiographic, morphological, and pathological observation of the knee joints at various times for up to 180 days.

Results: Motor ability on Day 180 was significantly lower in the MHCD group than in the Control (p＜0.01) and Hulth (p＜0.05) groups. Radiographic and morphological examination showed that the severity of knee joint deformity and articular cartilage injury were greater in the MHCD group than in the other groups. Pathological examination showed that cartilage thickness was significantly lower in the MHCD group than in the other groups at the same time points. The Mankin score on Day 180 was markedly higher in the MHCD group than in the Hulth (p＜0.05) and Control (p＜0.001) groups.

Conclusion: The MHCD model of OA closely resembles the pathophysiological processes of spontaneous knee OA in humans. The time required to develop knee OA is shorter using the MHCD model than using the Hulth method.

Association between medial meniscus extrusion under weight-bearing conditions and pain in early-stage knee osteoarthritis

PURPOSE

This study aimed to investigate the association between the severity of medial meniscus extrusion (MME) under weight bearing and pain in patients with early-stage knee osteoarthritis (OA).

METHODS

Twenty-eight patients with symptomatic early-stage knee OA (Kellgren and Lawrence grade ≤ 2) who visited our outpatient clinic between 2016 and 2018 were included in this cross-sectional study (mean age: 58.0 ± 11.6 years, female: n = 10). MME was evaluated under weight-bearing conditions using ultrasonography. Patients were divided into two groups according to the severity of MME under weight bearing: those with MME ≥ 3 mm were assigned to the severe group, whereas those with MME < 3 mm were assigned to the mild group. The knee injury osteoarthritis outcome score (KOOS) system was used to evaluate knee pain. The incidence of bone marrow lesions (BMLs) was evaluated using magnetic resonance images.

RESULTS

The KOOS pain score was significantly lower in the severe group than in the mild group (P < 0.05). The incidence of BMLs was significantly higher in the severe group (69%) than in the mild group (7%) (P < 0.001).

CONCLUSION

Patients with early-stage knee OA who have greater MME under weight-bearing have more intense knee pain and a higher incidence of BMLs.

Imaging of Synovial Inflammation in Osteoarthritis, From the AJR Special Series on Inflammation

Synovitis, inflammation of the synovial membrane, is a common manifestation in osteoarthritis (OA) and is recognized to play a role in the complex pathophysiology of OA. Increased recognition of the importance of synovitis in the OA disease process and potential as a target for treatment has increased the need for non-invasive detection and characterization of synovitis using medical imaging. Numerous imaging methods can assess synovitis involvement in OA with varying sensitivity and specificity as well as complexity. This article reviews the role of contrast-enhanced MRI, conventional MRI, novel unenhanced MRI, gray-scale ultrasound (US), and power Doppler US in the assessment of synovitis in patients with OA. The role of imaging in disease evaluation as well as challenges in conventional imaging methods are discussed. We also provide an overview into the potential utility of emerging techniques for imaging of early inflammation and molecular inflammatory markers of synovitis, including quantitative MRI, superb microvascular imaging, and PET. The potential development of therapeutic treatments targeting inflammatory features, particularly in early OA, would greatly increase the importance of these imaging methods for clinical decision making and evaluation of therapeutic efficacy.

Prevalence of ultrasound-detected knee synovial abnormalities in a middle-aged and older general population-the Xiangya Osteoarthritis Study

Background

There is paucity of data on the prevalence of ultrasound-detected synovial abnormalities in the general population, and the relationship between synovial changes and knee pain remains unclear. We examined the prevalence of synovial abnormalities on ultrasound and the relationship of these features with knee pain and radiographic osteoarthritis (ROA) in a community sample.

Methods

Participants aged 50 years or over were from the Xiangya Osteoarthritis Study, a community-based cohort study. Participants were questioned about chronic knee pain and underwent (1) ultrasonography of both knees to determine presence of synovial hypertrophy (≥ 4 mm), effusion (≥ 4 mm), and Power Doppler signal [PDS; yes/no]; and (2) standard radiographs of both knees (tibiofemoral and patellofemoral views) to determine ROA.

Results

There were 3755 participants (mean age 64.4 years; women 57.4%). The prevalence of synovial hypertrophy, effusion, and PDS were 18.1% (men 20.2%; women 16.5%), 46.6% (men 49.9%; women 44.2%), and 4.9% (men 4.9%; women 5.0%), respectively, and increased with age (P for trend < 0.05). Synovial abnormalities were associated with knee pain, with adjusted odds ratios (aORs) of 2.39 (95% confidence interval [CI] 2.00–2.86) for synovial hypertrophy, 1.58 (95%CI 1.39–1.80) for effusion, and 4.36 (95%CI 3.09–6.17) for PDS. Similar associations with ROA were observed, the corresponding aORs being 4.03 (95%CI 3.38–4.82), 2.01 (95%CI 1.76–2.29), and 6.49 (95%CI 4.51–9.35), respectively. The associations between synovial hypertrophy and effusion with knee pain were more pronounced among knees with ROA than those without ROA, and the corresponding P for interaction were 0.004 and 0.067, respectively.

Conclusions

Knee synovial hypertrophy and effusion are more common and increase with age, affecting men more than women. All three ultrasound-detected synovial abnormalities associate both with knee pain and ROA, and knee synovial hypertrophy or effusion and ROA may interact to increase the risk of knee pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02539-2.

Muscle activity while ambulating on stairs and slopes: A comparison between individuals scheduled and not scheduled for knee arthroplasty and healthy controls

OBJECTIVE

To examine muscle activity patterns of the lower limbs while ascending and descending stairs and slope in adults with knee Osteoarthritis (knee-OA), who were scheduled or not scheduled for Total Knee Replacement (TKR) and healthy controls.

METHODS

This cross-sectional study included three groups: knee-OA subjects scheduled for TKR (TKR group; N = 15) and not scheduled for TKR (NTKR group; N = 15) and age-matched controls (N = 11). Outcome measures included: joint range of motion (ROM), Timed Up and Go (TUG), joint pain levels, and functional disability (Oxford) score. Also, durations of muscle activity (rectus femoris, semitendinosus, medial gastrocnemius, bilaterally, and soleus, and tibialis anterior of the OA limb) were recorded while the subjects ascended and descended stairs and a level surface.

RESULTS

Both knee-OA groups had significantly higher Oxford scores and bilateral knee pain levels compared to the control group. The TKR group had higher TUG score compared to the NTKR group. The activation duration of the Tibialis Anterior of the OA limb while ascending and descending stairs and slope were higher in the TKR group compared to the NTKR group. No differences in muscle activity durations were found when comparing the OA limb to contralateral limb.

CONCLUSION

The muscle activity strategies differentiated between individuals scheduled and not scheduled for TKR. The longer duration of muscle activity of Tibialis Anterior muscle in the TKR group compared to the NTKR group suggest that customized prehabilitation program is required for these groups.

Unicompartmental Knee Arthroplasty: Minimal Important Difference and Patient Acceptable Symptom State for the Forgotten Joint Score

Background and Objectives: Unicompartmental knee arthroplasty (UKA) is a valid alternative to total knee arthroplasties (TKAs) in selected cases. After surgery, patients' experience and satisfaction were traditionally evaluated by pre- and postsurgical scores and Patient-Reported Outcome Measures (PROMs). Otherwise, a statistically significant change does not necessarily correlate to a clinically meaningful improvement when measured using PROMs. To evaluate the real effect of a specific treatment and understand the difference between groups in a clinical trial, it is necessary to use a meaningful quantum of change on the score assessed. The minimal clinically important difference (MCID) and the Patient Acceptable Symptom State (PASS) can provide this meaningful change. This paper aimed to calculate the MCID and the PASS of the Forgotten Joint Score (FJS-12) after UKA. Materials and Methods: A total of 40 patients with a mean age 72.5 ± 6.4 years undergoing UKA were assessed preoperatively and six months postsurgery using the FJS-12 and the Oxford Knee Score (OKS). The baseline and 6-month postoperative scores were compared using the Wilcoxon signed ranks test. The correlation was calculated with Spearman's rho. Both distribution-based approaches and anchor approaches were used to estimate MCID for the FJS-12. The 75th percentile and the Receiver operating characteristic (ROC) curve methods were used to calculate the PASS of FJS-12. Results: MCID estimates for normalized FJS-12 for UKA ranged from 5.68 to 19.82. The threshold of the FJS-12 with ROC method was 72.92 (AUC = 0.76). The cut-off value computed with the 75th percentile approach was 92.71. Conclusions: The MCID and PASS represent valid tools to assess the real perception of clinical improvement in patients who underwent UKA. The MCID value of FJS-12 was 12.5 for patients who underwent UKA. The value of the PASS for the FJS-12 in patients who underwent UKA was 72.92.

Using intra-articular allogenic lyophilized growth factors in primary knee osteoarthritis: a randomized pilot study

Objective: Investigating the safety in addition to clinical and structural efficacy of allogenic lyophilized growth factors (L-GFs) in patients with symptomatic primary knee osteoarthritis. Design: A prospective, open-label pilot study. A total of 31-patients randomized into non-intervention and intervention groups. Materials & methods: The intervention group received two intra-articular doses at baseline and after 2-months. Post-injection complications were documented, and the efficacy was assessed by Western Ontario and McMaster Universities Osteoarthritis Index scores and ultrasonography. Results: One dropout from the intervention group. The percentage of improvement of mean Western Ontario and McMaster Universities Osteoarthritis Index-scores and ultrasonography-detected effusion were statistically significant in the intervention group compared with the non-intervention. A brief, mild, post-injection pain was reported by all intervention group. Conclusion: This study provides the safety of intra-articular injection of allogenic L-GFs in knee osteoarthritis. The conclusion of efficacy was limited by small sample size and lack of control injection. Clinical trial registration: NCT04331327 (ClinicalTrials.gov, retrospectively registered).

Imaging of knee osteoarthritis: A review of current evidence and clinical guidelines

BACKGROUND

Knee osteoarthritis (OA) is one of the most common and debilitating degenerative joint diseases worldwide. While radiography is the most commonly used imaging modality, it is associated with drawbacks which newer modalities such as magnetic resonance imaging (MRI) and ultrasound could overcome. Nevertheless, the role of imaging in clinical practice and research in knee OA has not been clearly defined. Furthermore, guidelines on imaging in knee OA from different authoritative bodies have not been compared in previous studies. Therefore, the present review aims to summarise existing evidence and compare guidelines on the use of different imaging modalities in evaluating knee OA.

METHODS

This is a narrative review based on a search of published clinical guidelines and the PubMed database for articles published between 1 January 1990 and 31 May 2020.

RESULTS

There is no broad consensus on the value of imaging in patients with typical OA presentation. If imaging is required, current evidence and clinical guidelines support the use of radiography and MRI as first- and second-line diagnostic modalities respectively. Since radiographic OA features have limited sensitivity and do not manifest in early stages, MRI is the preferred option for whole-joint evaluation in OA research. Discrepancies exist regarding the use of alternative imaging modalities including ultrasound, computed tomography and nuclear medicine.

CONCLUSION

Radiography and MRI are the imaging modalities of choice. Other modalities have their respective advantages, and more research is warranted for the standardisation of image acquisition and interpretation methodology, in order to evaluate their validity, reliability and responsiveness in OA research.

Ultrasonographic Evaluation of Osteoarthritis-affected Knee Joints: Comparison with Kellgren-Lawrence Grading and Pain Scores

BACKGROUND

The objective was to compare ultrasonographic findings with clinical and radiographic findings in osteoarthritis (OA)-affected knee joints.

METHODS

This prospective study was conducted in Subharti Medical College, Meerut, after getting clearance from the ethical committee. Eighty-five symptomatic knees fulfilling American College of Rheumatology criteria for OA were included in the study. Patients with trauma, inflammatory, and infective conditions of the knee and with a history of intra-articular interventions and surgery were excluded. Demographic data, body mass index (BMI), visual analog scale (VAS), and Western Ontario and McMaster Universities Arthritis (WOMAC) questionnaire score were obtained. Kellgren-Lawrence (K-L) score was obtained on radiography. Ultrasonographic findings which were recorded include effusion, meniscal extrusion, femorotrochlear cartilage grading, maximum length of osteophytes at medial and lateral compartments, and presence or absence of Baker cyst.

RESULTS

A total of 85 consecutive symptomatic knees were examined. The male: female ratio was 22:63, with a mean age of 54.52 ± 9.44 years, mean duration of disease of 24.24 ± 19.14 months, mean BMI of 28.91 ± 3.69 kg/m2, and mean score of VAS and WOMAC pain scale of 6.27 ± 1.45 and 62.45 ± 10.96, respectively. K-L grading of 1, 2, 3, and 4 was reported in 12.9%, 21.2%, 25.9%, and 40% of the knees, respectively. The mean VAS score and WOMAC score showed statistically significant correlation with KL grading (P < 0.05). Knees with the presence of osteophytes, medial meniscal extrusion, effusion, and medial femoral trochlear cartilage grading showed statistically significant correlation with VAS and WOMAC scores (P < 0.05). However, the correlation was not significant for lateral meniscus extrusion and lateral femoral trochlear cartilage grading.

CONCLUSION

Our study found that K-L grading and few ultrasonographic criteria showed a significant positive correlation with pain scores, while few other ultrasonographic criteria did not. Both imaging modalities are complementary to each other, rather than one being superior to the other.

Assessment of knee osteoarthritis by ultrasonography and its association with knee pain

BACKGROUND

Pain is a significant cause of disability in knee osteoarthritis. Conventional radiography is widely used in the assessment of knee osteoarthritis, however radiographic findings do not correlate well with pain. Ultrasonography can be used to evaluate the soft tissue structures of the knee that can be related to pain.

OBJECTIVE

To evaluate pain-related soft tissue structures of the knee with ultrasonography.

METHODS

This cross-sectional study included a total of 198 knees from 99 patients with knee osteoarthritis. Knee pain and functional status were evaluated by performing visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). On the ultrasound, cartilaginous thickness, knee effusion and presence of Baker's cyst were assessed and the correlation to pain was investigated.

RESULTS

Baker's cyst was significantly more frequent in symptomatic knees (13.9%) compared to asymptomatic knees (2.5%). Patients with Baker's cyst had a significantly more limited degree of knee flexion, significantly higher resting VAS pain scores and worse WOMAC scores compared to patients without Baker's cyst. In log-linear analysis, presence of Baker's cyst increased the risk of pain by 2.94 times.

CONCLUSION

Ultrasound as a modality that is easily accessible, inexpensive and without radiation exposure is helpful to demonstrate factors related to pain in knee osteoarthritis by allowing assessment of soft tissue structures.

Setting up distinctive outcome measures for each osteoarthritis phenotype

Osteoarthritis (OA) is an evolving chronic joint disease with a huge global impact. Given the intricate nature of the etiopathogenesis and subsequent high heterogeneity in the clinical course of OA, it is crucial to discriminate between etiopathogenic endotypes and clinical phenotypes, especially in the early stages of the disease. In this sense, we propose that an OA phenotype should be properly assessed with a set of outcome measures including those specifically related to the main underlying pathophysiological mechanisms. Thus, each OA phenotype can be related to different and clinically meaningful outcomes. OA phenotyping would lead to an adequate patient stratification in well-designed clinical trials and the discovery of precise therapeutic approaches. A significant effort will be required in this field in light of inconclusive results of clinical trials of tissue-targeting agents for the treatment of OA.

Are OMERACT Knee Osteoarthritis Ultrasound Scores Associated With Pain Severity, Other Symptoms, and Radiographic and Magnetic Resonance Imaging Findings?

OBJECTIVE

To investigate the associations of Outcome Measures in Rheumatology (OMERACT) ultrasound scores for knee osteoarthritis (OA) with pain severity, other symptoms, and OA severity on radiographs and magnetic resonance imaging (MRI).

METHODS

Participants with symptomatic and mild to moderate radiographic knee OA underwent baseline dynamic ultrasound (US) assessment according to standardized OMERACT scanning protocol. Using the published US image atlas, a physician operator obtained semiquantitative or binary scores for US pathologies. Clinical severity was measured on numerical rating scale (NRS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) symptoms and pain subscores. OA severity was assessed using the Kellgren-Lawrence (KL) grade on radiographs and MRI Osteoarthritis Knee Score (MOAKS) on noncontrast-enhanced MRI. Separate linear regression models were used to determine associations of US OA pathologies with pain and KOOS subscores, and Spearman correlations were used for US scores with KL grade and MOAKS.

RESULTS

Eighty-nine participants were included. Greater synovial hypertrophy, power Doppler (PD), and meniscal extrusion scores were associated with worse NRS pain [β 0.92 (95% CI 0.25-1.58), β 0.73 (95% CI 0.11-1.35), and β 1.01 (95% CI 0.22-1.80), respectively]. All greater US scores, except for cartilage grade, demonstrated significant associations with worse KOOS symptoms, whereas only PD and meniscal extrusion were associated with worse KOOS pain. All US scores, except for PD, were significantly correlated with KL grade. US pathologies, except for cartilage, revealed moderate to good correlation with their MOAKS counterparts, with US synovitis having the greatest correlation (0.69, 95% CI 0.60-0.78).

CONCLUSION

OMERACT US scores revealed significant associations with pain severity, KL grade, and MOAKS.

Association between grayscale sonographic and clinical findings in severe knee osteoarthritis

PURPOSE

To assess whether ultrasonographic (US) findings associate with clinical findings in severe knee osteoarthritis (OA). Association of US findings with side-of-knee pain and inter-reader agreement of knee US were also evaluated.

METHODS

One-hundred-two patients (in total 123 knees) with severe knee OA were recruited for this cross-sectional study. US was performed by a single observer, and on 53 knees by two independent observers to assess inter-reader reliability. Preoperative clinical data was available for 69 knees. Cutoff values were applied to dichotomize US and clinical findings. The Chi-square test, Mann-Whitney test, and prevalence- and bias-adjusted kappa (PABAK) were applied for statistical analyses.

RESULTS

Seven of 99 associations tested were statistically significant. Associations were observed between range of flexion and lateral femoral (P = .009) and tibial (P = .001) osteophytes, mediolateral instability and damage to the lateral femoral cartilage (P = .014) and damage to the lateral meniscus (P = .031), and alignment and damage to the lateral femoral cartilage (P < .001), lateral tibial osteophytes (P = .037), and damage to the lateral meniscus (P < .001). A strong association was observed between medial-sided pain and same-sided cartilage damage and osteophytes (P < .001). That inter-reader agreement was excellent on the medial side of the knee joint (PABAK = 0.811-0.887).

CONCLUSIONS

US findings show a rather poor association with clinical OA findings. Inter-reader agreement of knee US is excellent on the medial side.

Stratifying Minimal Versus Severe Pain in Knee Osteoarthritis Using a Musculoskeletal Ultrasound Protocol

OBJECTIVE

The aim of this cross-sectional correlational study was to determine the association of pain with morphologic and inflammatory sonographic findings in patients with knee osteoarthritis.

METHODS

A total of 113 participants with knee osteoarthritis were assessed using visual analog scale pain score and sonography. Ultrasound evaluation included morphologic changes (ie, articular cartilage degeneration, medial and lateral meniscal protrusion, and presence of osteophytes on the joint margins) and inflammatory changes (ie suprapatellar effusion and/or synovitis, Baker cyst, superficial and deep infrapatellar effusion, pes anserine tendinopathy, and Hoffa panniculitis).

RESULTS

Cluster analysis via Ward's method grouped patients with minimal pain (visual analog scale score, 0-4) and with substantial pain (visual analog scale score, 5-10). Stepwise logistic regression yielded 5 variables that significantly explained the variation in the probability of perceived substantial pain at 10% level of significance: lateral cartilage clarity (LCC; P = .025), medial cartilage clarity (MCC; P = .20), medial cartilage thickness (MCT; P = .041), medial meniscus protrusion (MMP) (P = .029), and osteophytes at medial femoral margin (P = .082), with 63% overall prediction accuracy. When age and sex were added, 4 variables remained significant at a 10% level of significance: LCC, MCC, MCT, and MMP, with 65% overall prediction accuracy. The receiver operating characteristic curve of this model was 0.667.

CONCLUSION

The study was able to demonstrate that morphologic abnormalities in the ultrasound parameters for LCC, MCC, MCT, and MMP were able to predict significant joint pain in knee osteoarthritis. There were no inflammatory changes that contributed to significant joint pain in this study.

Soft Tissue Pathology Detected By Ultrasound Seem To Be Risk Factors for Painful Flare in Osteoarthritic Knee

BACKGROUND:

To our knowledge, the importance of US findings, pain (brief pain inventory (BPI)) and disability in osteoarthritic knee (OA) pain patients remain uncertain.

AIM:

The objectives are to evaluate the correlation of US findings, pain (brief pain inventory (BPI)) and disability in OA pain patients.

MATERIALS AND METHODS:

Eighty - three patients with OA knee were divided into two groups. The first group was OA as symptomatic knee group and the second group was an asymptomatic control group. The maximum sagittal height of synovial fluid in 12 scans at 0, 30, 60 and 90 degrees flexion knee in 3 major recesses were measured.

RESULTS:

There were a significant positive correlation between BPI Pain severity index, or BPI function interference index and a maximum height of effusion at 30-degree flexion angle in a supra-patellar recess in painful symptomatic knees. But, there was a significant negative correlation between BPI Pain severity index, and BPI function interference index and cartilage thickness in painful symptomatic knees.

CONCLUSION:

The increase of maximum height of synovial effusion at different angles of knee and decrease of cartilage thickness associated with pain and disability in OA pain patients and are being predictors for pain severity and disability in OA pain patients.

Selection and Investigation of a Primate Model of Spontaneous Degenerative Knee Osteoarthritis, the Cynomolgus Monkey (Macaca Fascicularis)

BACKGROUND The aim of this study was to identify a primate model of degenerative knee osteoarthritis (KOA) that may be more relevant for research studies on degenerative KOA in humans. MATERIAL AND METHODS Sixteen specific-pathogen-free (SPF) male cynomolgus monkeys (Macaca fascicularis) were divided into group A (n=8), an old group (22.0-25.3 years of age), and group B (n=8), a young group (3.0-5.2 years of age). For each primate, the behavior was observed, knee circumference was measured, knee joint X-rays were performed, and peripheral blood white blood cell (WBC) counts were measured, and the Kellgren and Lawrence (K-L) system was used for the classification of osteoarthritis. An enzyme-linked immunoassay (ELISA) was performed on knee joint fluid to measure levels of interleukin (IL)-1β, transforming growth factor (TGF)-β1, and matrix metalloproteinase (MMP)13. Changes in articular cartilage were evaluated using the Brittberg score and the Mankin histopathology grading score, respectively. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot were used to measure the expression of the NOTCH3, JAG1, and ACAN genes in knee cartilage specimens, and the findings in the two groups of primates were compared. RESULTS Seven old aged primates in group A were compared with group B, and showed significant differences in WBC count, synovial fluid IL-1β, TGF-β1, and MMP13 levels, expression levels of the NOTCH3, JAG1, and ACAN genes in knee cartilage specimens, and in the Brittberg and Mankin scores (all, P<0.05). CONCLUSIONS Cynomolgus monkeys (Macaca fascicularis) might be a model for age-related degenerative KOA.

What is the role of imaging in the clinical diagnosis of osteoarthritis and disease management?

While OA is predominantly diagnosed on the basis of clinical criteria, imaging may aid with differential diagnosis in clinically suspected cases. While plain radiographs are traditionally the first choice of imaging modality, MRI and US also have a valuable role in assessing multiple pathologic features of OA, although each has particular advantages and disadvantages. Although modern imaging modalities provide the capability to detect a wide range of osseous and soft tissue (cartilage, menisci, ligaments, synovitis, effusion) OA-related structural damage, this extra information has not yet favourably influenced the clinical decision-making and management process. Imaging is recommended if there are unexpected rapid changes in clinical outcomes to determine whether it relates to disease severity or an additional diagnosis. On developing specific treatments, imaging serves as a sensitive tool to measure treatment response. This narrative review aims to describe the role of imaging modalities to aid in OA diagnosis, disease progression and management. It also provides insight into the use of these modalities in finding targeted treatment strategies in clinical research.

Association between ultrasound-detected synovitis and knee pain: a population-based case-control study with both cross-sectional and follow-up data

BACKGROUND

An important role for synovial pathology in the initiation and progression of knee osteoarthritis has been emphasised recently. This study aimed to examine whether ultrasonography-detected synovial changes associate with knee pain (KP) in a community population.

METHODS

A case-control study was conducted to compare people with early KP (n = 298), established KP (n = 100) or no KP (n = 94) at baseline. Multinomial logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) between groups adjusted for radiographic osteoarthritis (ROA) severity and other confounding factors. After 1 year, 255 participants with early and established KP completed the follow-up questionnaire for changes in KP. Logistic regression with adjustment was used to determine predictors of KP worsening.

RESULTS

At baseline, effusion was associated with early KP (OR 2.64, 95% CI 1.57-4.45) and established KP (OR 5.07, 95% CI 2.74-9.38). Synovial hypertrophy was also associated with early KP (OR 5.43, 95% CI 2.12-13.92) and established KP (OR 13.27, 95% CI 4.97-35.43). The association with effusion diminished when adjusted for ROA. Power Doppler signal was uncommon (early KP 3%, established KP 2%, controls 0%). Baseline effusion predicted worsening of KP at 1 year (OR 1.95, 95% CI 1.05-3.64). However, after adjusting for ROA, the prediction was insignificant (adjusted OR 0.95, 95% CI 0.44-2.02).

CONCLUSIONS

Ultrasound effusion and synovial hypertrophy are associated with KP, but only effusion predicts KP worsening. However, the association/prediction is not independent from ROA. Power Doppler signal is uncommon in people with KP. Further study is needed to understand whether synovitis is directly involved in different types of KP.

Imaging in Osteoarthritis

With technologic advances and the availability of sophisticated computer software and analytical strategies, imaging plays an increasingly important role in understanding the disease process of osteoarthritis (OA). Radiography has limitations in that it can visualize only limited features of OA, such as osteophytes and joint space narrowing, but remains the most commonly used modality for establishing an imaging-based diagnosis of OA. This article describes the roles and limitations of different imaging modalities and discusses the optimum imaging protocol, imaging diagnostic criteria of OA, differential diagnoses, and what the referring physician needs to know.

Structure-symptom relationship with wide-area ultrasound scanning of knee osteoarthritis

The aetiology of knee pain in osteoarthritis (OA) is heterogeneous and its relationship with structural changes and function is unclear. Our goal was to determine the prevalence of wide-area scanned ultrasound-defined knee OA structural features and their association with pain and functional impairment in 79 symptomatic and 63 asymptomatic subjects. All subjects underwent ultrasound knee wide-area scanning and the severity of articular cartilage degeneration, the presence and size of osteophytes, and meniscal extrusion were evaluated. Subjects filled in a self-administrated questionnaire on present knee pain, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) on clinical symptoms and function over the past week. Cartilage changes were the most prevalent followed by lateral meniscal extrusion, osteophytes and medial meniscal extrusion. The global femoral cartilage grade associated strongly with pain and the WOMAC index. Site-specifically, early medial cartilage changes and thinning in sulcus and lateral site were associated with symptoms. The presence of femoral lateral osteophytes was also associated with both outcomes. Using the novel wide-area ultrasound scanning technique, we were able to confirm the negative impact of femoral cartilage OA changes on clinical symptoms. Presence, not necessarily size, of lateral femoral osteophytes was also associated with increased pain and disability.

Diagnosis and Longitudinal Assessment of Osteoarthritis: Review of Available Imaging Techniques

Osteoarthritis (OA) is a major chronic and global health care problem. Recent technological advances in imaging and postprocessing techniques have enhanced the understanding and characterization of the pathophysiology of this chronic and prevalent disease. Although plain radiograph remains the modality of choice for initial assessment of OA, recent studies have shown that advanced cross-sectional imaging can improve the early detection, grading, structural damage quantification, and risk stratification of OA. This article discusses the currently available evidence regarding both the conventional and novel imaging modalities that can be used for evaluation of patients with OA and its longitudinal assessment.

Synovial changes detected by ultrasound in people with knee osteoarthritis - a meta-analysis of observational studies

OBJECTIVES

To examine the prevalence of synovial effusion, synovial hypertrophy and positive Doppler signal (DS) detected by ultrasound (US) in people with knee osteoarthritis (OA) and/or knee pain compared to that in the general population.

METHOD

A systematic literature search was undertaken in Medline, EMBASE, Allied and Complementary Medicine, PubMed Web of Science, and SCOPUS databases in May 2015. Frequencies of US abnormalities in people with knee OA/pain, in the general population or asymptomatic controls were pooled using the random effects model. Publication bias and heterogeneity between studies were examined.

RESULTS

Twenty four studies in people with knee pain/OA and five studies of the general population or asymptomatic controls met the inclusion criteria. The pooled prevalence of US effusion, synovial hypertrophy and positive DS in people with knee OA/pain were 51.5% (95% CI 40.2 to 62.8), 41.5% (26.3-57.5) and 32.7% (8.34-63.24), respectively, which were higher than those in the general population or asymptomatic controls (19.9% (95%CI 7.8-35.3%), 14.5% (0-58.81), and 15.8 (3.08-35.36), respectively). People with knee OA (ACR criteria or radiographic OA) had greater prevalence of US abnormalities than people with knee pain (P = 0.037, P = 0.010 and P = 0.009, respectively).

CONCLUSIONS

US detected effusion, synovial hypertrophy and DS are more common in people with knee OA/pain, compared to the general population. These abnormalities relate more to presence of OA structural changes than to pain.

Reliability of a Proposed Ultrasonographic Grading Scale for Severity of Primary Knee Osteoarthritis

OBJECTIVES

The objective of this study was to examine the concordance of a grading scale (0–4) of medial femoral osteophytes in knee joint detected by ultrasound (US) compared with the corresponding grades (0–4) of Kellgren–Lawrence (K&L) scale of conventional radiography and clinical joint examination.

PATIENTS AND METHODS

A cross-sectional observational study included 160 patients with knee pain who fulfilled the American College of Rheumatology (ACR) criteria for knee osteoarthritis (KOA) and 20 patients with knee pain who have not fulfilled the ACR criteria for KOA. All patients were subjected to clinical assessment (Western Ontario and McMaster Universities Index of Osteoarthritis and global visual analog scale) and radiological assessment in the form of X-ray grading according to K&L grading scale and ultrasonographic assessment of medial femoral osteophytes according to a scale that was proposed by the first author and consisted of five grades (0–4), where grade 0 denoted no osteoarthritis and grade 4 denoted the most advanced grade of KOA. Grade 2 was divided into two subgrades A and B with grade 2B considered as a more advanced stage than grade 2A.

RESULTS

The proposed US grading scale had high sensitivity and specificity in detecting the different grades of KOA compared with K&L grading scale (a total sensitivity of 94.6% and a total specificity of 93.3%). Intra- and interreader reliability of US was excellent (kappa >0.93 and >0.85, respectively).

CONCLUSIONS

US can reliably detect the severity of KOA. Good agreement was found between the proposed US grading scale and K&L grading scale. The proposed US grading scale is simple and reliable.

Correlation among Radiographic, Arthroscopic and Pain Criteria for the Diagnosis of Knee Osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is the most common degenerative joint disorder leading to functional impairment and dependency in older adults. Early detection and intervention is of paramount importance in decreasing the morbidity. Radiography is the first investigation of choice for OA patients presenting with knee pain. But, there is a high degree of discordance between clinical and radiographic findings. Arthroscopy aids in accurate diagnosis of OA knee.

AIM

In view of the conflicting reports in the literature the present study was undertaken to report the correlation among radiographic, arthroscopic and pain findings in knee OA patients to facilitate early and precise diagnosis.

MATERIALS AND METHODS

Twenty eight cases (14 males and 14 females) of primary OA knee (7 each from radiographic grade 1 to 4) were screened and selected for the study. Spearman's rank correlation coefficients (Rho/r estimate) were calculated to determine the relationship between pain, radiographic and arthroscopic grades in patients with knee OA.

RESULTS

Among 28 patients, 10.71% had grade 1, 14.28% had grade 2, 25% had grade 3 and 50% had grade 4 arthroscopic findings. Overall Spearman's correlation coefficient (r) for radiographic and arthroscopic grades was 0.8077, 0.8212 for radiographic and pain grades and 0.7634 for arthroscopic and pain grades. Correlation coefficient could not be calculated for individual grades in isolation which would otherwise represent the factual correlation. The Mean arthroscopic grade for radiographic grades 1 to 4 were 1.57, 3.42, 3.57,4.0 respectively and the Mean pain grades for radiographic grades 1 to 4 were1.57, 2.57,3.28, 3.57 respectively. Radiological findings were found to lag behind the arthroscopic findings significantly.

CONCLUSION

Arthroscopic findings represent the exact extent and degree of the pathology of OA knee. Kellgren-Lawrence grading read with conventional Antero-posterior standing radiographs of knee underscores the arthroscopic findings significantly in grades 1, 2 and 3. Radiological and clinical findings (Apley's pain grading) in combination should be considered in concluding the final diagnosis and treatment of OA knee. Improvised criteria for precise diagnosis have to be evolved.

Imaging for osteoarthritis

Osteoarthritis (OA) is a widely prevalent disease worldwide and, with an increasing ageing society, is a challenge for the field of physical and rehabilitation medicine. Technologic advances and implementation of sophisticated post-processing instruments and analytic strategies have resulted in imaging playing a more and more important role in understanding the disease process of OA. Radiography is still the most commonly used imaging modality for establishing an imaging-based diagnosis of OA. The need for an effective non-surgical OA treatment is highly desired, but despite on-going research efforts no disease-modifying OA drugs have been discovered or approved to date. MR imaging-based studies have revealed some of the limitations of radiography. The ability of MR to image all relevant joint tissues within the knee and to visualize cartilage morphology and composition has resulted in MRI playing a key role in understanding the natural history of the disease and in the search for new therapies. Our review will focus on the roles and limitations of radiography and MRI with particular attention to knee OA. The use of other modalities (e.g. ultrasound, nuclear medicine, computed tomography (CT), and CT/MR arthrography) in clinical practice and OA research will also be briefly described. Ultrasound may be useful to evaluate synovial pathology in osteoarthritis, particularly in the hand.

Conventional and novel imaging modalities in osteoarthritis: current state of the evidence

PURPOSE OF REVIEW

Imaging modalities are currently an inseparable part of osteoarthritis diagnosis. In this review, we describe the current state of evidence regarding conventional and novel imaging modalities in evaluation of osteoarthritis. Modalities including radiography (qualitative and semi-quantitative assessments), ultrasonography, computed tomography [CT; conventional multidetector CT (MDCT), cone-beam CT (CBCT) and four-dimensional CT (4DCT)], MRI (MRI; semi-quantitative, quantitative and compositional) and PET and their applications are reviewed.

RECENT FINDINGS

Radiography is the modality of choice for initial assessment of osteoarthritis. However, due to its low sensitivity and specificity, numerous recent investigations have proposed MRI as a powerful addition to detect and grade osteoarthritis features, which are not apparent in radiography. Semi-quantitative MRI measurements are feasible to perform in routine clinical practice. Quantitative and compositional MRI measurements have extended the amount of information an MRI examination can provide regarding the three-dimensional shape and tissue composition of articular cartilage. 4DCT and CBCT are introduced as imaging examinations that may reveal biomechanical cartilage abnormalities in osteoarthritis joint by dynamic and weight-bearing evaluations, respectively. Recent PET studies may unveil the underlying metabolic activities that can be associated with osteoarthritis.

SUMMARY

In addition to the established role of radiographs, MRI is the advanced modality of choice for detection and quantification of various osteoarthritis features. 4DCT and CBCT may have specified applications when diagnosis of underlying motion abnormality or dynamic changes in weight-bearing situation is suspected. Future studies should elucidate the specific clinical applications of ultrasonography and PET.

Ultrasound of knee osteoarthritis: interobserver agreement and correlation with Western Ontario and McMaster Universities Osteoarthritis

The aim of this work was to assess the reproducibility of ultrasound findings of knee osteoarthritis and to correlate ultrasound findings with Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Prospective study was conducted upon 80 patients (56 F, 24 M; mean age 57 years) with primary osteoarthritis of knee joint. All patients underwent clinical assessment with calculation of WOMAC and high-resolution ultrasound of the knee joint. The ultrasound images were analyzed for cartilage thinning, osteophytes, synovial effusion, synovial proliferation, popliteal cyst, and meniscal protrusion. Image analysis was performed by two readers and linear regression analysis was used to determine association of ultrasound findings with WOMAC. There was excellent inter-observer agreement of both readers for cartilage thinning (k = 0.99, P = 0.001), osteophytes (k = 0.94, P = 0.001), synovial effusion (k = 0.98, P = 0.001), synovial thickening (k = 0.96, P = 0.001), popliteal cyst (k = 1.00, P = 0.001), and meniscal protrusion (k = 0.86, P = 0.001). There was significant association of WOMAC with cartilage changes (t = 3.406, 3.302, P = 0.001), osteophytes (t = 3.841, 3.006, P = 0.001), and synovial effusion (t = 4.140 and 2.787, P = 0.05) of both readers. We concluded that ultrasound is a reproducible method for assessment of knee osteoarthritis and well correlated with WOMAC.

Association between the severity of femoral condylar cartilage erosion related to knee osteoarthritis by ultrasonographic evaluation and the clinical symptoms and functions

OBJECTIVE

To determine the association between the severity of femoral condylar cartilage erosion resulting from knee osteoarthritis (OA) by an ultrasonographic grading system and the clinical symptoms and functions.

DESIGN

Cross-sectional study.

SETTING

A tertiary center.

PARTICIPANTS

Participants (N=101) with and without subjective complaints of knee discomfort were consecutively enrolled. Patients who had ever received knee arthroplasty, who had inflammatory arthritis, and whose knee flexion range of motion was <90° were excluded. A total of 194 knees were evaluated.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

A semiquantitative ultrasonographic grading system was used to evaluate the severity of femoral condylar cartilage erosion. The clinical symptoms and functions were evaluated with the visual analog scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Lequesne index. The association of the VAS/WOMAC/Lequesne index with the ultrasonographic grading was assessed.

RESULTS

Positive linear associations were found between the ultrasonographic grading and the following: the VAS and the total scores and pain subscales of both the Lequesne index and WOMAC. Multivariate logistic regression analysis revealed grade-dependent association between VAS and ultrasonographic grading after adjusting for age, sex, and body mass index. The WOMAC and Lequesne index scores were associated with the ultrasonographic grading in more severe degrees, particularly in the pain subscales.

CONCLUSIONS

This semiquantitative ultrasonographic grading system may well reflect the clinical symptoms and functions related to knee OA as evaluated by the VAS, WOMAC, and Lequesne index. This method provides a more comprehensive description and measurement of knee OA.

Imaging of non-osteochondral tissues in osteoarthritis

OBJECTIVE

The aim of this review is to describe imaging techniques for evaluation of non-osteochondral structures such as the synovium, menisci in the knee, labrum in the hip, ligaments and muscles and to review the literature from recent clinical and epidemiological studies of OA.

METHODS

This is a non-systematic narrative review of published literature on imaging of non-osteochondral tissues in OA. PubMed and MEDLINE search for articles published up to 2014, using the keywords osteoarthritis, synovitis, meniscus, labrum, ligaments, plica, muscles, magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), scintigraphy, and positron emission tomography (PET).

RESULTS

Published literature showed imaging of non-osteochondral tissues in OA relies primarily on MRI and ultrasound. The use of semiquantitative and quantitative imaging biomarkers of non-osteochondral tissues in clinical and epidemiological OA studies is reported. We highlight studies that have compared both imaging methodologies directly, and those that have established a relationship between imaging biomarkers and clinical outcomes. We provide recommendations as to which imaging protocols should be used to assess disease-specific changes regarding synovium, meniscus in the knee, labrum in the hip, and ligaments, and highlight potential pitfalls in their usage.

CONCLUSION

MRI and ultrasound are currently the most useful imaging modalities for evaluation of non-osteochondral tissues in OA. MRI evaluation of any tissue needs to be performed using appropriate MR pulse sequences. Ultrasound may be particularly useful for evaluation of small joints of the hand. Nuclear medicine and CT play a limited role in imaging of non-osteochondral tissues in OA.

Synovial pathology detected on ultrasound correlates with the severity of radiographic knee osteoarthritis more than with symptoms

OBJECTIVE

To [1] compare the frequency and severity of ultrasound (US) features in people with normal knees (controls), knee pain (KP), asymptomatic radiographic OA (ROA), and symptomatic OA (SROA), [2] examine relationships between US features, pain and radiographic severity, [3] explore the relationship between change in pain and US features over a 3-month period.

METHOD

Community participants were recruited into a multiple group case-control study. All underwent assessment for pain, knee radiographs and US examination for effusion, synovial hypertrophy, popliteal cysts and power Doppler (PD) signal within the synovium. A 3-month follow-up was undertaken in over half of control and SROA participants.

RESULTS

243 participants were recruited (90 controls; 59 KP; 32 ROA; 62 SROA). Effusion and synovial hypertrophy were more common in ROA and SROA participants. Severity of effusion and synovial hypertrophy were greater in SROA compared to ROA (P < 0.05). Severity of US effusion and synovial hypertrophy were correlated with radiographic severity (r = 0.6 and r = 0.7, P < 0.01) but the relationship between pain severity and US features was weak (r = 0.3, P < 0.01). In SROA participants, pain severity did not change in tandem with a change in synovial hypertrophy over time.

CONCLUSION

US abnormalities are common in OA. Effusion and synovial hypertrophy were moderately correlated with radiographic severity but the relationship with pain is less strong. The degree to which these features reflect "active inflammation" is questionable and they may be better considered as part of the total organ pathology in OA. Further studies are warranted to confirm these findings.

An ultrasound score for knee osteoarthritis: a cross-sectional validation study

OBJECTIVE

To develop standardized musculoskeletal ultrasound (MUS) procedures and scoring for detecting knee osteoarthritis (OA) and test the MUS score's ability to discern various degrees of knee OA, in comparison with plain radiography and the 'Knee injury and Osteoarthritis Outcome Score' (KOOS) domains as comparators.

METHOD

A cross-sectional study of MUS examinations in 45 patients with knee OA. Validity, reliability, and reproducibility were evaluated.

RESULTS

MUS examination for knee OA consists of five separate domains assessing (1) predominantly morphological changes in the medial compartment, (2) predominantly inflammation in the medial compartment, (3) predominantly morphological changes in the lateral compartment, (4) predominantly inflammation in the lateral compartment, and (5) effusion. MUS scores displayed substantial reliability and reproducibility, with interclass correlations coefficients ranging from 0.75 to 0.97 for the five domains. Construct validity was confirmed with statistically significant correlation coefficients (0.47-0.81, P < 0.01).

CONCLUSION

The MUS score suggested in this study was reliable and valid in detecting knee OA. In comparison with standing radiographs of the knees, the score detected all aspects of knee OA with relevant precision.

The course of ultrasonographic abnormalities in knee osteoarthritis: 1 year follow up

OBJECTIVE

Imaging of (peri)articular structures and inflammation with Ultrasonography (US) during the course of osteoarthritis (OA) might contribute to knowledge about early diagnosis of OA, prognosis and possibly the effect of disease modifying drugs. Our goal was to identify the prevalence of distinct patterns (stable vs fluctuating) in a set of US features in a cohort of patients receiving standard multimodal treatment for knee OA at T = 0, T = 3 months and T = 12 months.

DESIGN

This was a prospective, explorative study including 55 patients fulfilling the American College of Rheumatology clinical criteria for knee OA. Six US features were investigated including: effusion, synovial proliferation, infrapatellar bursitis, meniscal protrusion, Baker's cyst and cartilage thickness at three time points during 1 year. A composite inflammatory score was composed. Overall prevalence was assessed as well as individual patterns which were appointed as stable or unstable.

RESULTS

Inflammation like effusion and synovial hypertrophy does occur in over 40% of patients at some time in the year of follow up and shows a fluctuating pattern. Meniscal protrusion and Baker's cyst however are more stable features.

CONCLUSIONS

Our study gives insight in the prevalence and course of US abnormalities in patients with knee OA and contributes to the knowledge on the possible role of this imaging modality in research.

The role of imaging in osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disorder with no approved disease-modifying treatment available. The importance of imaging in assessing all joint structures involved in the disease process, including articular cartilage, meniscus, subarticular bone marrow, and synovium for diagnosis, prognostication, and follow-up, has been well recognized. In daily clinical practice, conventional radiography is still the most commonly used imaging technique for the evaluation of a patient with known or suspected OA and radiographic outcome measures are still the only approved end point by regulatory authorities in clinical trials. The ability of magnetic resonance imaging (MRI) to visualize all joint structures in three-dimensional fashion including tissue ultrastructure has markedly deepened our understanding of the natural history of the disease. This article describes the roles and limitations of different imaging modalities for clinical practice and research in OA, with a focus on radiography and MRI and an emphasis on the knee joint.