Long term evaluation of disease progression through the quantitative magnetic resonance imaging of symptomatic knee osteoarthritis patients: correlation with clinical symptoms and radiographic changes

The mediating role of synovitis in meniscus pathology and knee osteoarthritis radiographic progression

Meniscus pathologies (damage, extrusion) and synovitis are associated with knee osteoarthritis (KOA); however, whether synovitis mediates the relationship between meniscus pathologies and KOA radiographic progression remains unclear. We conducted an observational study in the Osteoarthritis Initiative (OAI) cohort, with a 48-month follow-up. Meniscus pathology and synovitis were measured by MRI osteoarthritis knee score (MOAKS) at baseline and 24 months, and a comprehensive synovitis score was calculated using effusion and Hoffa synovitis scores. The knee osteoarthritis radiographic progression was considered that Kellgren-Lawrence (KL) grade and joint space narrowing (JSN) grade at 48 months were increased compared to those at baseline. This study included a total of 589 participants, with KL grades mainly being KL1 (26.5%), KL2 (34.1%), and KL3 (30.2%) at baseline, while JSN grades were mostly 0 at baseline. A logistic regression model was used to analyze the relationship between meniscus pathology, synovitis, and KOA progression. Mediation analysis was used to evaluate the mediation effect of synovitis. The average age of the participants was 61 years old, 62% of which were female. The medial meniscus extrusion was longitudinally correlated with the progression of KL (odds ratio [OR]: 2.271, 95% confidence interval [CI]: 1.412-3.694) and medial JSN (OR: 3.211, 95% CI: 2.040-5.054). Additionally, the longitudinal correlation between medial meniscus damage and progression of KOA (OR: 1.853, 95% CI: 1.177-2.941) and medial JSN (OR: 1.655, 95% CI: 1.053-2.602) was significant. Synovitis was found to mediate the relationship between medial meniscus extrusion and KL and medial JSN progression at baseline (β: 0.029, 95% CI: 0.010-0.053; β: 0.022, 95% CI: 0.005-0.046) and beyond 24 months (β: 0.039, 95% CI: 0.016-0.068; β: 0.047, 95% CI: 0.020-0.078). However, we did not find evidence of synovitis mediating the relationship between meniscal damage and KOA progression. Synovitis mediates the relationship between medial meniscus extrusion (rather than meniscus damage) and KOA progression.

Emerging Trends in Magnetic Resonance Fingerprinting for Quantitative Biomedical Imaging Applications: A Review

Magnetic resonance imaging (MRI) stands as a vital medical imaging technique, renowned for its ability to offer high-resolution images of the human body with remarkable soft-tissue contrast. This enables healthcare professionals to gain valuable insights into various aspects of the human body, including morphology, structural integrity, and physiological processes. Quantitative imaging provides compositional measurements of the human body, but, currently, either it takes a long scan time or is limited to low spatial resolutions. Undersampled k-space data acquisitions have significantly helped to reduce MRI scan time, while compressed sensing (CS) and deep learning (DL) reconstructions have mitigated the associated undersampling artifacts. Alternatively, magnetic resonance fingerprinting (MRF) provides an efficient and versatile framework to acquire and quantify multiple tissue properties simultaneously from a single fast MRI scan. The MRF framework involves four key aspects: (1) pulse sequence design; (2) rapid (undersampled) data acquisition; (3) encoding of tissue properties in MR signal evolutions or fingerprints; and (4) simultaneous recovery of multiple quantitative spatial maps. This paper provides an extensive literature review of the MRF framework, addressing the trends associated with these four key aspects. There are specific challenges in MRF for all ranges of magnetic field strengths and all body parts, which can present opportunities for further investigation. We aim to review the best practices in each key aspect of MRF, as well as for different applications, such as cardiac, brain, and musculoskeletal imaging, among others. A comprehensive review of these applications will enable us to assess future trends and their implications for the translation of MRF into these biomedical imaging applications.

Relationship between medial meniscus extrusion and damage to medial stabilizers: Should extrusion be considered significant only when more than 3 mm?

BACKGROUND

This study was conducted with patients with anterior and medial extrusion of the medial meniscus (MM-AE, MM-ME) to investigate the relationship of the amount of extrusion with damage to the meniscus, meniscofemoral ligament (MFL), meniscotibial ligament (MTL), presence of effusion, osteoarthritis (OA) grade and other medial stablizers. A cut-off value for significant MM-ME was also suggested.

METHODS

All patients aged 18 and above who had measurable MM extrusion on knee MRI were included. Patients with acute injury detected on knee MRI and any disease that could disrupt the anatomy were not included. The relationship between the amount of MM-AE, MM-ME and the investigated comorbidities were evaluated. The patients were divided into two: those with and without positive findings for each comorbidities. The amount of MM-AE, MM-ME were evaluated. ROC analysis was undertaken for significant differences, and cut-off values were determined.

RESULTS

There was a correlation between MM-ME and age, weight, and BMI (p < 0.001, p = 0.027, p = 0.025, respectively). The amount of MM-ME was higher in the groups with OA (p = 0.007), MTL damage (p < 0.001), MFL damage (p < 0.001), meniscus damage (p < 0.001), effusion (p < 0.001), and the amount of MM-AE was higher in the groups with OA (p = 0.042), effusion (p = 0.002). The cut-off values of MM-ME were determined to be 2.69 mm (MTL), 2.65 mm (MFL), 2.49 mm (meniscus), and 2.85 mm (OA).

CONCLUSION

OA grade, effusion, and meniscus, MTL, and MFL damage were all found to be related to the amount of MM-ME. MM-ME values 2.49-2.85 mm may indicate meniscus, MFL, MTL damage and OA.

Exploring the differences between radiographic joint space width and MRI cartilage thickness changes using data from the IMI-APPROACH cohort

OBJECTIVE

Longitudinal weight-bearing radiographic joint space width (JSW) and non-weight-bearing MRI-based cartilage thickness changes often show weak correlations. The current objective was to investigate these correlations, and to explore the influence of different factors that could contribute to longitudinal differences between the two methods.

METHODS

The current study included 178 participants with medial osteoarthritis (OA) out of the 297 knee OA participants enrolled in the IMI-APPROACH cohort. Changes over 2 years in medial JSW (ΔJSWmed), minimum JSW (ΔJSWmin), and medial femorotibial cartilage thickness (ΔMFTC) were assessed using linear regression, using measurements from radiographs and MRI acquired at baseline, 6 months, and 1 and 2 years. Pearson R correlations were calculated. The influence of cartilage quality (T2 mapping), meniscal extrusion (MOAKS scoring), potential pain-induced unloading (difference in knee-specific pain scores), and increased loading (BMI) on the correlations was analyzed by dividing participants in groups based on each factor separately, and comparing correlations (slope and strength) between groups using linear regression models.

RESULT

Correlations between ΔMFTC and ΔJSWmed and ΔJSWmin were statistically significant (p < 0.004) but weak (R < 0.35). Correlations were significantly different between groups based on cartilage quality and on meniscal extrusion: only patients with the lowest T2 values and with meniscal extrusion showed significant moderate correlations. Pain-induced unloading or BMI-induced loading did not influence correlations.

CONCLUSIONS

While the amount of loading does not seem to make a difference, weight-bearing radiographic JSW changes are a better reflection of non-weight-bearing MRI cartilage thickness changes in knees with higher quality cartilage and with meniscal extrusion.

Meniscal Extrusion: Diagnosis, Etiology, and Treatment Options

PURPOSE OF REVIEW

The concept of meniscal extrusion has recently been recognized as a hallmark of meniscus dysfunction. This review examines contemporary literature regarding the pathophysiology, classification, diagnosis, treatment, and future directions for investigation regarding meniscus extrusion.

RECENT FINDINGS

Meniscus extrusion, defined as >3 mm of radial displacement of the meniscus, leads to altered knee biomechanics and accelerated knee joint degeneration. Meniscus extrusion has been associated with degenerative joint disease, posterior root and radial meniscal tears, and acute trauma. Meniscus centralization and meniscotibial ligament repair have been proposed as techniques to address meniscal extrusion with promising biomechanical, animal model, and early clinical reports. Further studies on the epidemiology of meniscus extrusion and associated long-term nonoperative outcomes will help to elucidate its role in meniscus dysfunction and resultant arthritic development. Understanding and appreciation for the anatomic attachments of the meniscus will help to inform future repair techniques. Long-term reporting on the clinical outcomes of meniscus centralization techniques will yield insights into the clinical significance of meniscus extrusion correction.

A pilot randomized controlled trial evaluating outdoor community walking for knee osteoarthritis: walk

OBJECTIVES

To determine the feasibility of a randomized controlled trial (RCT) examining outdoor walking on knee osteoarthritis (KOA) clinical outcomes and magnetic resonance imaging (MRI) structural changes.

METHOD

This was a 24-week parallel two-arm pilot RCT in Tasmania, Australia. KOA participants were randomized to either a walking plus usual care group or a usual care control group. The walking group trained 3 days/week. The primary outcome was feasibility assessed by changes being required to the study design, recruitment, randomization, program adherence, safety, and retention. Exploratory outcomes were changes in symptoms, physical performance/activity, and MRI measures.

RESULTS

Forty participants (mean age 66 years (SD 1.4) and 60% female) were randomized to walking (n = 24) or usual care (n = 16). Simple randomization resulted in a difference in numbers randomized to the two groups. During the study, class sizes were reduced from 10 to 8 participants to improve supervision, and exclusion criteria were added to facilitate program adherence. In the walking group, total program adherence was 70.0% and retention 70.8% at 24 weeks. The walking group had a higher number of mild adverse events and experienced clinically important improvements in symptoms (e.g., visual analogue scale (VAS) knee pain change in the walking group: - 38.7 mm [95% CI - 47.1 to - 30.3] versus usual care group: 4.3 mm [- 4.9 to 13.4]).

CONCLUSIONS

This study supports the feasibility of a full-scale RCT given acceptable adherence, retention, randomization, and safety, and recruitment challenges have been identified. Large symptomatic benefits support the clinical usefulness of a subsequent trial.

TRIAL REGISTRATION NUMBER

12618001097235. Key Points • This pilot study is the first to investigate the effects of an outdoor walking program on knee osteoarthritis clinical outcomes and MRI joint structure, and it indicates that a full-scale RCT is feasible. • The outdoor walking program (plus usual care) resulted in large improvements in self-reported knee osteoarthritis symptoms compared to usual care alone. • The study identified recruitment challenges, and the manuscript explores these in more details and provides recommendations for future studies.

Radiographic OA, bone marrow lesions, higher body mass index and medial meniscal root tears are significantly associated with medial meniscus extrusion with OA or medial meniscal tears: a systematic review and meta-analysis

PURPOSE

Medial meniscus extrusion (MME) refers to the protrusion of the medial meniscus beyond the tibial edge by more than 3 mm, leading to a deficiency of the hoop strain. MME commonly occurs in conjunction with osteoarthritis (OA) or medial meniscal tears (MMT). However, factors associated with concomitant MME in patients with OA or MMT have not been systematically reviewed. This study aims to perform a systematic review and meta-analysis to identify factors associated with concomitant MME in OA or MMT.

METHODS

The systematic review of the literature was performed according to PRISMA. A literature search was conducted in 4 databases. All original human studies that reported the available evidence on factors associated with concomitant MME in patients with OA or MMT were included. Pooled binary variables were analyzed by odds ratios (OR) and 95% CIs, and pooled continuous variables were evaluated by mean difference (MD) and 95% CIs.

RESULTS

Ten studies on OA (5993 patients) and eight studies on MMT (872 patients) met the inclusion criteria. The overall pooled incidence of MME was 43% (95% CI, 37-50%) for OA, 61% (95% CI 43-77%) for MMT, and 85% (95% CI 72-94%) for medial meniscal root tears (MMRT). For the population with OA, Factors significantly associated with MME included radiographic OA [OR 4.24; 95% CI 3.07-5.84; P < 0.0001], bone marrow lesions [OR, 3.35; 95% CI 1.61-6.99; P = 0.0013], cartilage damage [OR, 3.25; 95% CI 1.60-6.61; P = 0.0011], and higher body mass index (BMI) [MD, 1.81; 95% CI 1.15-2.48; P < 0.0001]. Factors strongly associated with increased risk of MME for MMT included medial meniscal root [OR, 8.39; 95% CI 2.84-24.82; P < 0.0001] and radial tears [OR, 2.64; 95% CI 1.18-5.92; P < 0.0001].

CONCLUSION

Radiographic OA, bone marrow lesions, cartilage damage, and higher BMI were significantly associated with concomitant MME with OA. Furthermore, medial meniscal root and radial tears were significantly associated with an increased risk of MME in patients with MMT.

LEVEL OF EVIDENCE

IV.

Personalized volumetric assessment of lower body muscles in patients with knee injuries: A descriptive case series

BACKGROUND

Patients with knee joint pathology present with variable muscular responses across the muscles of the lower limb and pelvis. Conventional approaches to characterizing muscle function are limited to gross strength assessments that may overlook subtle changes both in the thigh, hip and shank musculature.

PURPOSE

To describe individualized patterns of lower extremity muscle volumes in patients with knee pathologies.

METHODS

This was a retrospective case series performed in a University medical center. Nine patients diagnosed with meniscus tear recommended to undergo meniscectomy volunteered. Participants underwent 3.0 Tesla magnetic resonance imaging (MRI) of the lower extremities. Thirty-five MRI-derived muscle volumes were compared between limbs and expressed as percentage asymmetry. For additional context, z-scores were also calculated for mass- and height-normalized muscles and pre-determined muscle groupings relative to a normative database.

RESULTS

There were no consistent patterns observed when considering between-limb asymmetries among all patients. The ankle musculature (dorsiflexors, plantar flexors, and invertors) was the only muscle group to be consistently smaller than normal for all patients, with the psoas major and flexor hallucis longus being the only individual muscles. The severity or chronicity of injury and presence of surgical intervention did not appear to have a clear effect on muscle volumes.

CONCLUSION

Patients with a history of meniscal pathology demonstrate inconsistent patterns of lower extremity muscle volumes about the hip, knee, and ankle between limbs and in comparison to uninjured individuals. These data support the need for individualized assessment and intervention in this population.

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.

Study protocol for a randomised controlled trial of diacerein versus placebo to treat knee osteoarthritis with effusion-synovitis (DICKENS)

Background

There is an unmet need for treatments for knee osteoarthritis (OA). Effusion-synovitis is a common inflammatory phenotype of knee OA and predicts knee pain and structural degradation. Anti-inflammatory therapies, such as diacerein, may be effective for this phenotype. While diacerein is recommended for alleviating pain in OA patients, evidence for its effectiveness is inconsistent, possibly because studies have not targeted patients with an inflammatory phenotype. Therefore, we will conduct a multi-centre, randomised, placebo-controlled double-blind trial to determine the effect of diacerein on changes in knee pain and effusion-synovitis over 24 weeks in patients with knee OA and magnetic resonance imaging (MRI)-defined effusion-synovitis.

Methods

We will recruit 260 patients with clinical knee OA, significant knee pain, and MRI-detected effusion-synovitis in Hobart, Melbourne, Adelaide, and Perth, Australia. They will be randomly allocated to receive either diacerein (50mg twice daily) or identical placebo for 24 weeks. MRI of the study knee will be performed at screening and after 24 weeks of intervention. The primary outcome is improvement in knee pain at 24 weeks as assessed by a 100-mm visual analogue scale (VAS). Secondary outcomes include improvement in volumetric (ml) and semi-quantitative (Whole-Organ Magnetic Resonance Imaging Score, 0–3) measurements of effusion-synovitis using MRI over 24 weeks, and improvement in knee pain (VAS) at 4, 8, 12, 16, and 20 weeks. Intention-to-treat analyses of primary and secondary outcomes will be performed as the primary analyses. Per protocol analyses will be performed as the secondary analyses.

Discussion

This study will provide high-quality evidence to determine whether diacerein improves pain, changes disease trajectory, and slows disease progression in OA patients with effusion-synovitis. If diacerein proves effective, this has the potential to significantly benefit the substantial proportion (up to 60%) of knee OA patients with an inflammatory phenotype.

Trial registration

Australian and New Zealand Clinical Trial Registry ACTRN12618001656224. Registered on 08 October 2018.

High levels of TDO2 in relation to pro-inflammatory cytokines in synovium and synovial fluid of patients with osteoarthritis

Background

Tryptophan 2,3-dioxygenase (TDO2) is the primary enzyme that catabolizes tryptophan to kynurenine. Numerous studies have suggested that TDO2 is involved in inflammation-related diseases. However, its role in osteoarthritis (OA) has not yet been investigated. The aim of the present study was to explore the levels of TDO2 in the synovium and synovial fluid (SF) of patients with OA and its correlation with clinical manifestations and levels of pro-inflammatory cytokines. 

Methods 

Synovium and SF samples were collected from patients with OA and patients with joint trauma (controls) during surgery. An enzyme-linked immunosorbent assay (ELISA) was used to measure TDO2, interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) levels in the synovium and SF. Diagnostic performance of TDO2 in the synovium to discriminate between controls and OA patients was assessed using receiver operating characteristic (ROC) curve analysis. Correlations between TDO2 levels, OA clinical features, and pro-inflammatory cytokines were evaluated using Pearson correlation analysis. Effects of IL-1β or TNF-α stimulation on TDO2 expression in OA-fibroblast-like synoviocytes (OA-FLS) were also examined.

Results

The levels of TDO2, IL-1β, and TNF-α in the synovium of patients with OA were found to be significantly higher than those in controls. ROC curve analysis revealed an area under the curve (AUC) of 0.800 with 64.3% sensitivity and 85.0% specificity of TOD2 in the synovium, which enabled discriminating patients with OA from controls. Moreover, protein expression of TDO2 was upregulated to a greater extent in OA-FLS than in normal synovial fibroblasts (NSF). Furthermore, the levels of TDO2 showed significantly positive correlation with IL-1β and TNF-α levels in the synovium and SF. TDO2 levels in the synovium were also positively correlated with the Kellgren-Lawrence score. Additionally, TDO2 protein expression was significantly increased in IL-1β‒ or TNF-α‒stimulated OA-FLS than in control FLS.

Conclusion

These data indicate that highTDO2 levels in the synovium can be correlated with pro-inflammatory cytokines and severity of OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05567-4.

Effects of physical exercise and body weight on disease-specific outcomes of people with rheumatic and musculoskeletal diseases (RMDs): systematic reviews and meta-analyses informing the 2021 EULAR recommendations for lifestyle improvements in people with RMDs

BACKGROUND

A European League Against Rheumatism (EULAR) taskforce was convened to develop recommendations for lifestyle behaviours in rheumatic and musculoskeletal diseases (RMDs). This paper reviews the literature on the effects of physical exercise and body weight on disease-specific outcomes of people with RMDs.

METHODS

Three systematic reviews were conducted to summarise evidence related to exercise and weight in seven RMDs: osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, axial spondyloarthritis (axSpA), psoriatic arthritis, systemic sclerosis and gout. Systematic reviews and original studies were included if they assessed exercise or weight in one of the above RMDs, and reported results regarding disease-specific outcomes (eg, pain, function, joint damage). Systematic reviews were only included if published between 2013-2018. Search strategies were implemented in the Medline, Embase, Cochrane Library of systematic reviews and CENTRAL databases.

RESULTS

236 articles on exercise and 181 articles on weight were included. Exercise interventions resulted in improvements in outcomes such as pain and function across all the RMDs, although the size of the effect varied by RMD and intervention. Disease activity was not influenced by exercise, other than in axSpA. Increased body weight was associated with worse outcomes for the majority of RMDs and outcomes assessed. In general, study quality was moderate for the literature on exercise and body weight in RMDs, although there was large heterogeneity between studies.

CONCLUSION

The current literature supports recommending exercise and the maintenance of a healthy body weight for people with RMDs.

Meniscal Extrusion: A Narrative Review

Background:

Meniscal extrusion, referred to as an external displacement of the meniscus, is a commonly encountered but often overlooked magnetic resonance imaging finding in the knee joint. Meniscal extrusion alters the biomechanical properties of the meniscus, leading to accelerated cartilage degeneration and early osteoarthritic changes. The literature contains discrepancies about meniscal extrusion on topics ranging from definition to diagnosis. This narrative review outlines the pathogenesis, natural history, diagnosis, and treatment of meniscal extrusion.

Purpose:

To review the current literature on meniscal extrusion, from pathogenesis to treatment, and to provide recommendations for future research.

Study Design:

Narrative review.

Methods:

A computer-based search of the PubMed, Ovid Medline, and Cochrane Library databases was used to perform a comprehensive literature review on meniscal extrusion. A total of 81 studies was ultimately included in the review.

Results:

The literature review highlighted the current ambiguity in definition, difficulty in clinical diagnosis, and low level of awareness of this condition. This review covers all aspects related to meniscal extrusion and identifies many of its lesser known aspects.

Conclusion:

In the current literature, meniscal extrusion remains a lesser known albeit common condition because of its relatively silent nature along with lack of knowledge among orthopaedic surgeons. Further studies are warranted to provide better understanding and management of this condition.

Clinical relevance of MRI knee abnormalities in Australian rules football players: a longitudinal study

Background/Aim

The clinical relevance of MRI knee abnormalities in athletes is unclear. This study aimed to determine the prevalence of MRI knee abnormalities in Australian Rules Football (ARF) players and describe their associations with pain, function, past and incident injury and surgery history.

Methods

75 male players (mean age 21, range 16–30) from the Tasmanian State Football League were examined early in the playing season (baseline). History of knee injury/surgery and knee pain and function were assessed. Players underwent MRI scans of both knees at baseline. Clinical measurements and MRI scans were repeated at the end of the season, and incident knee injuries during the season were recorded.

Results

MRI knee abnormalities were common at baseline (67% bone marrow lesions, 16% meniscal tear/extrusion, 43% cartilage defects, 67% effusion synovitis). Meniscal tears/extrusion and synovial fluid volume were positively associated with knee symptoms, but these associations were small in magnitude and did not persist after further accounting for injury history. Players with a history of injury were at a greater risk of having meniscal tears/extrusion, effusion synovitis and greater synovial fluid volume. In contrast, players with a history of surgery were at a greater risk of having cartilage defects and meniscal tears/extrusion. Incident injuries were significantly associated with worsening symptoms, BML development and incident meniscal damage.

Conclusions

MRI abnormalities are common in ARF players, are linked to a previous knee injury and surgery history, as well as incident injury but do not dictate clinical symptomatology.

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.

Comparison between 2D radiographic weight-bearing joint space width and 3D MRI non-weight-bearing cartilage thickness measures in the knee using non-weight-bearing 2D and 3D CT as an intermediary

Background:

In knee osteoarthritis, radiographic joint space width (JSW) is frequently used as a surrogate marker for cartilage thickness; however, longitudinal changes in radiographic JSW have shown poor correlations with those of magnetic resonance imaging (MRI) cartilage thickness. There are fundamental differences between the techniques: radiographic JSW represents two-dimensional (2D), weight-bearing, bone-to-bone distance, while on MRI three-dimensional (3D) non-weight-bearing cartilage thickness is measured. In this exploratory study, computed tomography (CT) was included as a third technique, as it can measure bone-to-bone under non-weight-bearing conditions. The objective was to use CT to compare the impact of weight-bearing versus non-weight-bearing, as well as bone-to-bone JSW versus actual cartilage thickness, in the knee.

Methods:

Osteoarthritis patients (n = 20) who were treated with knee joint distraction were included. Weight-bearing radiographs, non-weight-bearing MRIs and CTs were acquired before and 2 years after treatment. The mean radiographic JSW and cartilage thickness of the most affected compartment were measured. From CT, the 3D median JSW was calculated and a 2D projectional image was rendered, positioned similarly and measured identically to the radiograph. Pearson correlations between the techniques were derived, both cross-sectionally and longitudinally.

Results:

Fourteen patients could be analyzed. Cross-sectionally, all comparisons showed moderate to strong significant correlations (R = 0.43–0.81; all p < 0.05). Longitudinal changes over time were small; only the correlations between 2D CT and 3D CT (R = 0.65; p = 0.01) and 3D CT and MRI (R = 0.62; p = 0.02) were statistically significant.

Conclusion:

The poor correlation between changes in radiographic JSW and MRI cartilage thickness appears primarily to result from the difference in weight-bearing, and less so from measuring bone-to-bone distance versus cartilage thickness.

Association between meniscal volume and development of knee osteoarthritis

OBJECTIVE

To assess the association between meniscal volume, its change over time and the development of knee OA after 30 months in overweight/obese women.

METHODS

Data from the PRevention of knee Osteoarthritis in Overweight Females study were used. This cohort included 407 women with a BMI ≥ 27 kg/m2, free of OA-related symptoms. The primary outcome measure was incident OA after 30 months, defined by one out of the following criteria: medial or lateral joint space narrowing (JSN)  ≥ 1.0 mm, incident radiographic OA [Kellgren and Lawrence (K&L)  ≥ 2], or incident clinical OA. The secondary outcomes were either of these items separately. Menisci at both baseline and follow-up were automatically segmented to obtain meniscal volume and delta-volumes. Generalized estimating equations were used to evaluate associations between the volume measures and the outcomes.

RESULTS

Medial and lateral baseline and delta-volumes were not significantly associated to the primary outcome. Lateral meniscal baseline volume was significantly associated to lateral JSN [odds ratio (OR) = 0.87; 95% CI: 0.75, 0.99], while other measures were not. Medial and lateral baseline volume were positively associated to K&L incidence (OR = 1.32 and 1.22; 95% CI: 1.15, 1.50 and 1.03, 1.45, respectively), while medial and lateral delta-volume were negatively associated to K&L incidence (OR = 0.998 and 0.997; 95% CI: 0.997, 1.000 and 0.996, 0.999, respectively). None of the meniscal measures were significantly associated to incident clinical OA.

CONCLUSION

Larger baseline meniscal volume and the decrease of meniscal volume over time were associated to the development of structural OA after 30 months in overweight and obese women.

Towards understanding mechanistic subgroups of osteoarthritis: 8-year cartilage thickness trajectory analysis

Many studies have validated cartilage thickness as a biomarker for knee osteoarthritis (OA); however, few studies investigate beyond cross-sectional observations or comparisons across two timepoints. By characterizing the trajectory of cartilage thickness changes over 8 years in healthy individuals from the OA initiative data set, this study discovers associations between the dynamics of cartilage changes and OA incidence. A fully automated cartilage segmentation and thickness measurement method were developed and validated against manual measurements: mean absolute error = 0.11-0.14 mm (n = 4129 knees) and automatic reproducibility = 0.04-0.07 mm (n = 316 knees). The mean thickness for the medial and lateral tibia (MT, LT), central weight-bearing medial and lateral femur (cMF, cLF), and patella (P) cartilage compartments were quantified for 1453 knees at seven timepoints. Trajectory subgroups were defined per cartilage compartment such as stable, thinning to thickening, accelerated thickening, plateaued thickening, thickening to thinning, accelerated thinning, or plateaued thinning. For tibiofemoral compartments, the stable (22%-36%) and plateaued thinning (22%-37%) trajectories were the most common, with an average initial velocity (μm/month), acceleration (μm/month² ) for the plateaued thinning trajectories LT: -2.66, 0.0326; MT: -2.49, 0.0365; cMF: -3.51, 0.0509; and cLF: -2.68, 0.041. In the patella compartment, the plateaued thinning (35%) and thickening to thinning (24%) trajectories were the most common, with an average initial velocity, acceleration for each -4.17, 0.0424; 1.95, -0.0835. Knees with nonstable trajectories had higher adjusted odds of OA incidence than stable trajectories: accelerated thickening, accelerated thinning, and plateaued thinning trajectories of the MT had adjusted odds ratio (OR) of 18.9, 5.48, and 1.47, respectively; in the cMF, adjusted OR of 8.55, 10.1, and 2.61, respectively.

Association between current medication use and progression of radiographic knee osteoarthritis: data from the Osteoarthritis Initiative

Objective

Use of specific medications may accelerate the progression of radiographic knee OA (RKOA). Our aim was to examine the effect of medication use on the progression of RKOA.

Methods

We used longitudinal data from the Osteoarthritis Initiative (OAI), an observational study of risk factors for knee OA. At baseline, we selected participants with RKOA (Kellgren–Lawrence grade ≥2) and excluded those with a history of knee-related injury/surgery and other musculoskeletal disorders. Current medication use (use/non-use in the previous 30 days) and radiographic medial minimum joint space width (mJSW) data were available at baseline and annually up to 96 months follow-up. We used random effects, panel regression to assess the association between current medication use (non-users as reference group) and change in mJSW.

Results

Of 2054 eligible participants, 2003 participants with baseline mJSW data were included [55.7% female, mean age 63.3 (s.d. 8.98) years]. Of seven medication classes, at baseline NSAIDs were the most frequently used analgesia (14.7%), anti-histamine (10.4%) use was frequent and the following comorbidity medications were used most frequently: statins (27.4%), anti-hypertensives (up to 15.0%), anti-depressant/anxiolytics/psychotropics (14.0%), osteoporosis-related medication (10.9%) and diabetes-related medication (6.9%). Compared with current non-users, current use of NSAIDs was associated with a loss of mJSW (b = −0.042, 95% CI −0.08, −0.0004). No other associations were observed.

Conclusions

In current users of NSAIDs, mJSW loss was increased compared with current non-users in participants with RKOA. Clinical trials are required to assess the potential disease-modifying effects of these medications.

Shortest time interval for detecting the progression of knee osteoarthritis on consecutive X-rays

Objectives

This study aims to find the shortest needed time interval between two consecutive anteroposterior (AP) knee X-rays of the same patient to determine the progression of knee osteoarthritis (KOA) by a trained eye.

Patients and methods

In this retrospective study, 2,145 AP knee X-rays of 848 primary KOA patients (331 males, 517 females; mean age 65±9 years; range, 50 to 92 years) followed-up between January 2014 and December 2017 were used. Randomly generated 1,280 pairs of knee X-rays were shown to 14 orthopedic surgeons working in the Department of Orthopedics and Traumatology, and then the physicians were asked to select the second X-ray of the same arthritis knee. The physicians completed the test twice. The patient's age, gender, time interval between two radiographs and the responses of the physicians were recorded.

Results

Our results showed that if the time interval between the two radiographs was six months or more, the correct estimation rates increased gradually. When the time interval was 36 months and more, the ratio reached 92%. The sensitivity and specificity rate of the method was 81%, while the positive predictive value was 86%. However, interestingly, age or gender did not have any effect on this result.

Conclusion

In our study, X-rays taken in less than six months apart could not give additional information about the radiographic progression of KOA. To discern between the progression of KOA, we recommend that there be a 12 to 18-month interval between consecutive X-rays. The data of our study can be used for a routine algorithm to be developed for the evaluation of KOA patients.

Transection of the medial meniscus anterior horn results in cartilage degeneration and meniscus remodeling in a large animal model

The meniscus plays a central load-bearing role in the knee joint. Unfortunately, meniscus injury is common and can lead to joint degeneration and osteoarthritis (OA). In small animal models, progressive degenerative changes occur with the unloading of the meniscus via destabilization of the medial meniscus (DMM). However, few large animal models of DMM exist and the joint-wide initiation of the disease has not yet been defined in these models. Thus, the goal of this study is to develop and validate a large animal model of surgically induced DMM and to use multimodal (mechanical, histological, and magnetic resonance imaging) and multiscale (joint to tissue level) quantitative measures to evaluate degeneration in both the meniscus and cartilage. DMM was achieved using an arthroscopic approach in 13 Yucatan minipigs. One month after DMM, joint contact area decreased and peak pressure increased, indicating altered load transmission as a result of meniscus destabilization. By 3 months, the joint had adapted to the injury and load transmission patterns were restored to baseline, likely due to the formation and maturation of a fibrovascular scar at the anterior aspect of the meniscus. Despite this, we found a decrease in the indentation modulus of the tibial cartilage and an increase in cartilage histopathology scores at 1 month compared to sham-operated animals; these deleterious changes persisted through 3 months. Over this same time course, meniscus remodeling was evident through decreased proteoglycan staining in DMM compared to sham menisci at both 1 and 3 months. These findings support that arthroscopic DMM results in joint degeneration in the Yucatan minipig and provide a new large animal testbed in which to evaluate therapeutics and interventions to treat post-traumatic OA that originates from a meniscal injury.

Statistical shape modelling provides a responsive measure of morphological change in knee osteoarthritis over 12 months

OBJECTIVES

Responsive biomarkers are needed to assess the progression of OA and their lack has hampered previous clinical trials. Statistical shape modelling (SSM) from radiographic images identifies those at greatest risk of fast-progression or joint replacement, but its sensitivity to change has not previously been measured. This study evaluates the responsiveness of SSM in knee OA in a 12-month observational study.

METHODS

A total of 109 people were recruited who had undergone knee radiographs in the previous 12 months, and were grouped based on severity of radiographic OA (Kellgren-Lawrence grading). An SSM was built from three dual-energy X-ray absorptiometry scans at 6-month intervals. Change-over-time and OA were assessed using generalized estimating equations, standardized response means (SRM) and reliable change indices.

RESULTS

Mode 1 showed typical features of radiographic OA and had a strong link with Kellgren-Lawrence grading but did not change significantly during the study. Mode 3 showed asymmetrical changes consistent with medial cartilage loss, osteophytes and joint malalignment, and was responsive to change, with a 12-month SRM of 0.63. The greatest change was observed in the moderate radiographic OA group (SRM 0.92) compared with the controls (SRM 0.21), and the reliable change index identified 14% of this group whose progression was clinically significant.

CONCLUSION

Shape changes linked the progression of osteophytosis with increasing malalignment within the joint. Modelling of the whole joint enabled quantification of change beyond the point where bone-to-bone contact has been made. The knee SSM is, therefore, a responsive biomarker for radiographic change in knees over 12 months.

Identification of the most important features of knee osteoarthritis structural progressors using machine learning methods

Objectives:

The aim was to identify the most important features of structural knee osteoarthritis (OA) progressors and classification using machine learning methods.

Methods:

Participants, features and outcomes were from the Osteoarthritis Initiative. Features were from baseline (1107), including articular knee tissues (135) assessed by quantitative magnetic resonance imaging (MRI). OA progressors were ascertained by four outcomes: cartilage volume loss in medial plateau at 48 and 96 months (Prop_CV_48M, 96M), Kellgren–Lawrence (KL) grade ⩾ 2 and medial joint space narrowing (JSN) ⩾ 1 at 48 months. Six feature selection models were used to identify the common features in each outcome. Six classification methods were applied to measure the accuracy of the selected features in classifying the subjects into progressors and non-progressors. Classification of the best features was done using an automatic machine learning interface and the area under the curve (AUC). To prioritize the top five features, sparse partial least square (sPLS) method was used.

Results:

For the classification of the best common features in each outcome, Multi-Layer Perceptron (MLP) achieved the highest AUC in Prop_CV_96M, KL and JSN (0.80, 0.88, 0.95), and Gradient Boosting Machine for Prop_CV_48M (0.70). sPLS showed the baseline top five features to predict knee OA progressors are the joint space width, mean cartilage thickness of the medial tibial plateau and sub-regions and JSN.

Conclusion:

In this comprehensive study using a large number of features (n = 1107) and MRI outcomes in addition to radiological outcomes, we identified the best features and classification methods for knee OA structural progressors. Data revealed baseline X-ray and MRI-based features could predict early OA knee progressors and that MLP is the best classification method.

Determining a Threshold of Medial Meniscal Extrusion for Prediction of Knee Pain and Cartilage Damage Progression Over 4 Years: Data From the Osteoarthritis Initiative

BACKGROUND. The extent of medial meniscal extrusion (MME) that is associated with structural and symptomatic progression of knee osteoarthritis has not been defined yet. OBJECTIVE. The purpose of our study was to investigate MRI-based thresholds of MME that are associated with structural progression of knee degenerative disease and symptoms over a period of 4 years. METHODS. We studied 328 knees of 235 participants that were randomly selected from the Osteoarthritis Initiative cohort. MME was quantified on coronal sections of intermediate-weighted MRI sequences obtained at 3 T. Knee pain and cartilage abnormalities were measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale and the cartilage whole-organ MRI score (WORMS). General estimating equations with logistic regression models were used to correlate baseline MME and changes in pain (WOMAC) and cartilage damage (WORMS). ROC analyses were performed to determine the area under the ROC curve (AUROC). Individual thresholds were determined by maximizing the product of sensitivity and specificity. RESULTS. The AUROC for predicting progression of knee pain, medial compartment cartilage damage, and medial tibial cartilage damage were 0.71, 0.70, and 0.72, respectively, and the individual thresholds for MME were 2.5, 2.7, and 2.8 mm. A single threshold of 2.5 mm was determined by maximizing the mean of the product of sensitivity and specificity of the three outcome variables (knee pain progression, medial compartmental cartilage damage progression, and medial tibial cartilage damage progression). CONCLUSION. MME was associated with knee pain and cartilage damage progression over 4 years. A single threshold of 2.5 mm was found to be the most useful threshold for predicting knee pain, medial compartment cartilage damage progression, and tibial cartilage damage progression over 4 years. CLINICAL IMPACT. This threshold could be used to standardize the diagnostic criterion of extrusion and to better characterize the risk for subsequent structural and symptomatic progression of knee osteoarthritis.

The Difference in Medial Meniscal Extrusion between Non-Weight-Bearing and Weight-Bearing Positions in People with and without Medial Compartment Knee Osteoarthritis

BACKGROUND

Medial meniscal extrusion (MME) has been correlated with medial meniscal injury and progression of medial knee osteoarthritis (OA).

OBJECTIVE

To examine the difference in MME between non-weight-bearing (supine) and weight-bearing (standing) positions in patients with and without medial knee OA. Determine the correlation between body mass index (BMI), Kellgren-Lawrence (KL) grade, Knee Osteoarthritis Outcome Score (KOOS), and MME.

DESIGN

Prospective.

SETTING

Tertiary institution PM&R Department.

PARTICIPANTS

Forty five participants (29 female, 16 male), 24 with healthy knees and 21 with OA.

METHODS OR INTERVENTIONS

A single physician sonographer measured supine and standing MME with ultrasound (US) on each participant. The physician was blinded to all measurements. BMI was recorded on all participants. KL grades and KOOS questionnaires were obtained for the OA group.

MAIN OUTCOME MEASURES

MME in supine and standing positions, change in MME from supine to standing, BMI, KL grade, and KOOS subscale scores.

RESULTS

MME increased .52 mm from supine to standing (P < .001). MME was greater in the OA group in both the supine (P = .002) and standing (P < .001) positions. Increasing BMI was moderately correlated with increasing MME (supine P = .001, standing <.001). Increasing age was correlated with increasing MME (supine P = .012, standing P = .002). Increasing KL grade (from 1 to 4) was correlated with increasing MME (supine P = .015, standing = .006). There was a small-to-moderate correlation between KOOS activities of daily living (ADL) subscale score and change in MME from supine to standing (P = .035). The change in MME from supine to standing positions had a small-to-moderate correlation (P = .035) with KOOS ADL subscale score alone but did not correlate with any of the other KOOS subscale scores or KOOS total scores. Receiver operating characteristic curve analysis suggested a standing MME value of 4.2 mm provides a positive likelihood ratio of 6.02 for knee OA.

CONCLUSIONS

MME is greater in those with OA and with weight-bearing. MME correlates with BMI, age, KL grade, and the KOOS ADL subscale score. Finally, standing MME of 4.2 mm yielded a higher positive likelihood ratio to differentiate between healthy knees and those with medial compartment OA than the previously reported value of 3.0 mm.

Comparison of Clinical and Semiquantitative Cartilage Grading Systems in Predicting Outcomes After Arthroscopic Partial Meniscectomy

OBJECTIVE. Cartilage loss on preoperative knee MRI is a predictor of poor outcomes after arthroscopic partial meniscectomy. The purpose of this study was to compare the ability to predict outcomes after arthroscopic partial meniscectomy with a clinically used modified Outerbridge system versus a semiquantitative MRI Osteoarthritis Knee Score system for grading cartilage loss. MATERIALS AND METHODS. Patients who underwent preoperative knee MRI within 6 months of arthroscopic partial meniscectomy and who had outcomes available from the time of surgery and 1 year later were eligible for inclusion. Cases were evaluated by two radiologists and one radiology fellow with the use of both grading systems. The accuracy of each system in discriminating between surgical success and failure was estimated using the ROC curve (AUC) with 95% CIs. A Wald test was used to assess noninferiority of the clinical grading system. Interreader agreement regarding the accuracy of the grading systems in predicting outcomes was also compared. RESULTS. A total of 78 patients (38 women and 40 men; mean age, 56.6 years) were included in the study. A prediction model using clinical grading (AUC = 0.695; 95% CI, 0.566-0.824) was noninferior (p = 0.047) to a model using MRI Osteoarthritis Knee Score grading (AUC = 0.683; 95% CI, 0.539-0.827). Both MRI prediction models performed better than a model using demographic characteristics only (AUC = 0.667; 95% CI, 0.522-0.812). Inter-reader agreement with clinical grading (80.8%) was higher than that with MRI Osteoarthritis Knee Score grading (65.0%; p = 0.012). CONCLUSION. A clinically used system to grade cartilage loss on MRI is as effective as a semiquantitative system for predicting outcomes after arthroscopic partial meniscectomy, while also offering improved interreader agreement.

Deep learning risk assessment models for predicting progression of radiographic medial joint space loss over a 48-MONTH follow-up period

OBJECTIVE

To develop and evaluate deep learning (DL) risk assessment models for predicting the progression of radiographic medial joint space loss using baseline knee X-rays.

METHODS

Knees from the Osteoarthritis Initiative without and with progression of radiographic joint space loss (defined as ≥ 0.7 mm decrease in medial joint space width measurement between baseline and 48-month follow-up X-rays) were randomly stratified into training (1400 knees) and hold-out testing (400 knees) datasets. A DL network was trained to predict the progression of radiographic joint space loss using the baseline knee X-rays. An artificial neural network was used to develop a traditional model for predicting progression utilizing demographic and radiographic risk factors. A combined joint training model was developed using a DL network to extract information from baseline knee X-rays as a feature vector, which was further concatenated with the risk factor data vector. Area under the curve (AUC) analysis was performed using the hold-out test dataset to evaluate model performance.

RESULTS

The traditional model had an AUC of 0.660 (61.5% sensitivity and 64.0% specificity) for predicting progression. The DL model had an AUC of 0.799 (78.0% sensitivity and 75.5% specificity), which was significantly higher (P < 0.001) than the traditional model. The combined model had an AUC of 0.863 (80.5% sensitivity and specificity), which was significantly higher than the DL (P = 0.015) and traditional (P < 0.001) models.

CONCLUSION

DL models using baseline knee X-rays had higher diagnostic performance for predicting the progression of radiographic joint space loss than the traditional model using demographic and radiographic risk factors.

Varus alignment increases medial meniscus extrusion and peak contact pressure: a biomechanical study

PURPOSE

Assessment of medial meniscus extrusion (MME) has become increasingly popular in clinical practice to evaluate the dynamic meniscus function and diagnose meniscus pathologies. The purpose of this biomechanical study was to investigate the correlation between MME and the changes in joint contact pressure in varus and valgus alignment. It was hypothesized that varus alignment would result in significantly higher MME along with a higher joint contact pressure in the medial compartment.

METHODS

Eight fresh-frozen human cadaveric knees were axially loaded, with a 750 N compressive load, in full extension with the mechanical axis shifted to intersect the tibial plateau at 30% and 40% (varus), 50% (neutral), 60% and 70% (valgus) of its width (TPW). Tibiofemoral peak contact pressure (PCP), mean contact pressure (MCP) and contact area (CA) were determined using pressure-sensitive films. MME was obtained via ultrasound at maximum load.

RESULTS

MME was significantly increased from valgus (1.32 ± 0.22 mm) to varus alignment (3.16 ± 0.24 mm; p < 0.001). Peak contact pressure at 30% TPW varus alignment was significantly higher compared to 60% TPW valgus (p = 0.018) and 70% TPW valgus (p < 0.01). MME significantly correlated with PCP (r = 0.56; p < 0.001) and MCP (r = 0.47, p < 0.01) but not with CA (r = 0.23; n.s.).

CONCLUSION

MME was significantly increased in varus alignment, compared to neutral or valgus alignment, with an intact medial meniscus. It was also significantly correlated with PCP and MCP within the medial compartment. However, valgus malalignment and neutral axis resulted in reduced MME and contact pressure. Lower limb alignment must be taken into account while assessing MME in clinical practice.

LEVEL OF EVIDENCE

Controlled laboratory study.

US detection of medial meniscus extrusion can predict the risk of developing radiographic knee osteoarthritis: a 5-year cohort study

OBJECTIVES

To clarify the relationship between the baseline value of medial meniscus extrusion (MME) and the radiographic change of knee osteoarthritis (KOA) through a 5-year follow-up.

METHODS

Overall, 472 participants and 944 knees were eligible. MME (mm) was measured at the baseline, and KOA was radiographically evaluated at both baseline and 5-year follow-up by Kellgren-Lawrence grade (KLG). Radiographic KOA (ROA) was defined as the knee showing KLG ≥ 2. Incident ROA (iROA) was defined if the baseline KLG of 0-1 increased to KLG ≥ 2 in 5 years. Progressive ROA (pROA) was defined if the baseline KLG of 2-3 worsened to a higher grade in 5 years. Receiver operating characteristic (ROC) curve and generalized estimating equations were used for analysis.

RESULTS

Of 574 non-ROA knees at the baseline, 43 knees (7.5%) developed iROA; of 370 ROA knees, 47 knees (12.7%) developed pROA. Based on the ROC curves, 4 mm was the optimal cutoff to detect the risk of iROA (area under curve [AUC] 0.639 [right knee]; AUC 0.641 [left knee]) and that of pROA (AUC 0.750 [right knee]; AUC 0.863 [left knee]). Multiple regression analysis showed that the 4-mm cutoff of MME was significantly associated with both the prevalence of iROA (regression coefficient [B] 1.909; p ≤ 0.001; adjusted odds ratio [aOR] 6.746) and that of pROA (B 1.791; p ≤ 0.001; aOR 5.993).

CONCLUSIONS

On ultrasonography, the participants with more extruded medial meniscus showed a higher prevalence of both iROA and pROA. Ultrasonography could identify patients who had a risk of developing KOA.

KEY POINTS

• Through a 5-year follow-up, the current cohort study was conducted to clarify the relationship between the baseline value of medial meniscus extrusion (MME) and the radiographic change of knee osteoarthritis (KOA). • More extruded medial meniscus evaluated by ultrasonography was associated with the development of radiographic KOA. • Ultrasonography could identify the patients who had a risk of developing KOA, and the 4-mm cutoff of MME was optimal to detect this risk.

Machine-learning-based patient-specific prediction models for knee osteoarthritis

Osteoarthritis (OA) is an extremely common musculoskeletal disease. However, current guidelines are not well suited for diagnosing patients in the early stages of disease and do not discriminate patients for whom the disease might progress rapidly. The most important hurdle in OA management is identifying and classifying patients who will benefit most from treatment. Further efforts are needed in patient subgrouping and developing prediction models. Conventional statistical modelling approaches exist; however, these models are limited in the amount of information they can adequately process. Comprehensive patient-specific prediction models need to be developed. Approaches such as data mining and machine learning should aid in the development of such models. Although a challenging task, technology is now available that should enable subgrouping of patients with OA and lead to improved clinical decision-making and precision medicine.

Ultrasound Assessment of Weight-Bearing and Non-Weight-Bearing Meniscal Extrusion: A Reliability Study

BACKGROUND

Ultrasound has become a useful instrument in evaluating musculoskeletal pathology. Recent studies suggest that ultrasound imaging of weight-bearing menisci may enhance the assessment of knee pathology, such as osteoarthritis (OA) and meniscal injuries.

OBJECTIVE

The primary aim of this study was to determine the intrarater and interrater reliability of ultrasound measurements of medial meniscal extrusion (MME) after a brief training session.

DESIGN

Prospective reliability study.

SETTING

Physical medicine and rehabilitation (PM&R) department within a tertiary care institution.

PARTICIPANTS

Forty-five participants (29 female, 16 male) were recruited to serve as models, 24 of whom had healthy knees and 21 of whom had radiographically confirmed medial compartment knee OA. Three physician sonographers (1 = experienced, 1 = sports medicine fellow, 1 = post-graduate year [PGY]-4 PM&R resident) were recruited to serve as operators.

METHODS OR INTERVENTIONS

Operators received a brief training session on identifying and measuring MME. All operators measured bilateral MME in each model in the standing and supine positions on two separate days. Operators were blinded to all measurements.

MAIN OUTCOME MEASUREMENTS

Primary outcomes were inter- and intrarater intraclass correlation coefficients (ICCs) of MME measurements among operators with different levels of ultrasound experience.

RESULTS

Supine MME intrarater reliability ICCs were 0.927, 0.885, and 0.780 for the experienced physician, sports medicine fellow, and PGY-4 operators, respectively. Standing MME intrarater reliability ICCs were 0.941, 0.902, and 0.824 for the experienced physician, sports medicine fellow, and PGY-4 operators, respectively. Interrater reliability ICCs were 0.896 and 0.842 for supine and standing measurements, respectively. There was a statistically significant increase in intrarater reliability with experience between the PGY-4 resident and experienced physician operators.

CONCLUSIONS

Operators with different levels of ultrasound experience demonstrated good MME measurement intra- and interrater reliabilities in both supine and standing positions.

Associations of Joint Line Tenderness and Patellofemoral Grind With Long-Term Knee Joint Outcomes: Data From the Osteoarthritis Initiative

OBJECTIVE

To examine whether joint line tenderness and patellofemoral grind from physical examination were associated with cartilage volume loss, worsening of radiographic osteoarthritis, and the risk of total knee replacement.

METHODS

This study examined 4,353 Osteoarthritis Initiative participants. For each measurement of joint line tenderness and patellofemoral grind, the patterns were defined as no (none at baseline and at 1 year), fluctuating (present at either time point), and persistent (present at both time points). Cartilage volume loss and worsening of radiographic osteoarthritis over 4 years were assessed using magnetic resonance imaging and radiographs, and total knee replacement over 6 years was assessed.

RESULTS

A total of 35.0% of participants had joint line tenderness, and 15.8% had patellofemoral grind. Baseline patellofemoral grind, but not joint line tenderness, was associated with increased cartilage volume loss (1.08% per year versus 0.96% per year; P = 0.02) and an increased risk of total knee replacement (odds ratio [OR] 1.55 [95% confidence interval (95% CI) 1.11-2.17]; P = 0.01). While the patterns of joint line tenderness were not significantly associated with joint outcomes, participants with persistent patellofemoral grind had an increased rate of cartilage volume loss (1.30% per year versus 0.90% per year; P < 0.001) and an increased risk of total knee replacement (OR 2.10 [95% CI 1.30-3.38]; P = 0.002) compared with those participants without patellofemoral grind.

CONCLUSION

Patellofemoral grind, but not joint line tenderness, may represent a clinical marker associated with accelerated cartilage volume loss over 4 years and an increased risk of total knee replacement over 6 years. This simple clinical examination may provide clinicians with an inexpensive way to identify those at higher risk of disease progression who should be targeted for surveillance and management.

A Novel Arthroscopic Classification of Degenerative Medial Meniscus Posterior Root Tears Based on the Tear Gap

Background:

Degenerative medial meniscus posterior root tears (MMPRTs) are reportedly associated with medial compartment osteoarthritis and meniscal extrusion with a displaced gap from the root insertion. However, degenerative MMPRTs have not yet been clearly classified according to arthroscopic findings.

Purpose:

To classify degenerative MMPRTs according to the tear gap and to investigate how the classification could reflect the joint condition properly.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent arthroscopic surgery, performed by a single orthopaedic surgeon, for degenerative MMPRTs between August 2006 and February 2017 were included. MMPRTs were classified according to tear patterns observed during arthroscopic surgery (type 1, incomplete root tear; types 2-5, complete root tears), with each type further divided by the size of the tear gap, defined as the degree of tear displacement from the root (type 2, no gap or overlapped; type 3, gap of 1-3 mm; type 4, gap of 4-6 mm; type 5, gap of ≥7 mm). We compared preoperative factors, including the Kellgren-Lawrence (K-L) grade, absolute extrusion, relative percentage of extrusion (RPE), tear gap on magnetic resonance imaging (MRI), and mechanical alignment, as well as intraoperative factors, including chondral wear at surgery, between each MMPRT type.

Results:

A total of 116 root tears were categorized according to this classification: type 1, 16.4% (19 knees); type 2, 9.5% (11 knees); type 3, 40.5% (47 knees); type 4, 25.0% (29 knees); and type 5, 8.6% (10 knees). Chondral wear of the medial femoral condyle (MFC) (P = .001), K-L grade (P = .001), meniscal extrusion (P = .001), and tear gap on MRI (P = .001) showed a tendency to increase with a higher tear type. Chondral wear (ρ for MFC = 0.388; ρ for MTP = 0.311), K-L grade (ρ = 0.390), and meniscal extrusion (ρ for absolute extrusion = 0.500; ρ for RPE = 0.451) showed a moderate correlation with tear type, whereas tear gap on MRI (ρ = 0.907) showed a strong correlation with tear type.

Conclusion:

Our study introduces a new classification based on the tear gap that can concisely describe a degenerative MMPRT. The classification system demonstrated that a higher tear type (increasing displacement of the tear gap in arthroscopic surgery) is associated with higher meniscal extrusion, severe chondral wear, and greater severity of arthritis.

Association Between Bone Marrow Lesions, Chondral Lesions, and Pain in Patients Without Radiographic Evidence of Degenerative Joint Disease Who Underwent Arthroscopic Partial Meniscectomy

Background

Bone marrow lesions (BMLs) have been found on magnetic resonance imaging in patients with meniscal tears.

Purpose

We sought to determine the prevalence and location of BMLs, the association between BMLs and chondral lesions, and the association between BMLs and pain in patients without radiographic evidence of degenerative joint disease who underwent arthroscopic partial meniscectomy (APM).

Study Design

Cohort study; Level of evidence, 2.

Methods

We performed a secondary analysis of the Chondral Lesions And Meniscus Procedures (ChAMP) randomized controlled trial. BMLs were assessed on preoperative magnetic resonance imaging, and chondral lesions were documented at the time of surgery. Pain was assessed preoperatively and at 1 year after APM using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Knee injury and Osteoarthritis Outcome Score (KOOS). The chi-square test was used to examine the association between BMLs and chondral lesions, and the F test was used to examine the association between BMLs and pain.

Results

Of 241 patients, 58.9% had ≥1 BMLs, and most were located on the medial tibial plateau (MTP; 74.6%) and/or medial femoral condyle (MFC; 28.9%). Most MTP BMLs were submeniscal (56%), and most MFC BMLs extended beyond the meniscus (73%). There were more MFC chondral lesions for patients with any MFC BMLs (P = .01) and submeniscal MFC BMLs (P = .02) versus those without BMLs, and there was no association between BMLs and chondral lesions on the MTP. There was also no association between BMLs and preoperative or postoperative pain scores.

Conclusion

In patients without radiographic evidence of degenerative joint disease who underwent APM, BMLs were found in 58.9% of knees and were primarily located in the medial compartment. There was a borderline statistically significant association between BMLs and chondral lesions for the MFC; however, BMLs were not associated with pain scores preoperatively or at 1 year after surgery.

Deep convolutional neural network for segmentation of knee joint anatomy

PURPOSE

To describe and evaluate a new segmentation method using deep convolutional neural network (CNN), 3D fully connected conditional random field (CRF), and 3D simplex deformable modeling to improve the efficiency and accuracy of knee joint tissue segmentation.

METHODS

A segmentation pipeline was built by combining a semantic segmentation CNN, 3D fully connected CRF, and 3D simplex deformable modeling. A convolutional encoder-decoder network was designed as the core of the segmentation method to perform high resolution pixel-wise multi-class tissue classification for 12 different joint structures. The 3D fully connected CRF was applied to regularize contextual relationship among voxels within the same tissue class and between different classes. The 3D simplex deformable modeling refined the output from 3D CRF to preserve the overall shape and maintain a desirable smooth surface for joint structures. The method was evaluated on 3D fast spin-echo (3D-FSE) MR image data sets. Quantitative morphological metrics were used to evaluate the accuracy and robustness of the method in comparison to the ground truth data.

RESULTS

The proposed segmentation method provided good performance for segmenting all knee joint structures. There were 4 tissue types with high mean Dice coefficient above 0.9 including the femur, tibia, muscle, and other non-specified tissues. There were 7 tissue types with mean Dice coefficient between 0.8 and 0.9 including the femoral cartilage, tibial cartilage, patella, patellar cartilage, meniscus, quadriceps and patellar tendon, and infrapatellar fat pad. There was 1 tissue type with mean Dice coefficient between 0.7 and 0.8 for joint effusion and Baker's cyst. Most musculoskeletal tissues had a mean value of average symmetric surface distance below 1 mm.

CONCLUSION

The combined CNN, 3D fully connected CRF, and 3D deformable modeling approach was well-suited for performing rapid and accurate comprehensive tissue segmentation of the knee joint. The deep learning-based segmentation method has promising potential applications in musculoskeletal imaging.

Knee pain as a predictor of structural progression over 4 years: data from the Osteoarthritis Initiative, a prospective cohort study

Background

There is evidence that knee pain not only is a consequence of structural deterioration in osteoarthritis (OA) but also contributes to structural progression. Clarifying this is important because targeting the factors related to knee pain may offer a clinical approach for slowing the progression of knee OA. The aim of this study was to examine whether knee pain over 1 year predicted cartilage volume loss, incidence and progression of radiographic osteoarthritis (ROA) over 4 years.

Methods

Osteoarthritis Initiative participants with no ROA (Kellgren-Lawrence grade ≤ 1) (n = 2120) and with ROA (Kellgren-Lawrence grade > 2) (n = 2249) were examined. Knee pain was assessed at baseline and 1 year using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Knee pain patterns were categorised as no pain (WOMAC pain < 5 at baseline and 1 year), fluctuating pain (WOMAC pain > 5 at either time point) and persistent pain (WOMAC pain > 5 at both time points). Cartilage volume, incidence and progression of ROA were assessed using magnetic resonance imaging and x-rays at baseline and 4-years.

Results

In both non-ROA and ROA, greater baseline WOMAC knee pain score was associated with increased medial and lateral cartilage volume loss (p ≤ 0.001), incidence (OR 1.07, 95% CI 1.01–1.13) and progression (OR 1.07, 95% CI 1.03–1.10) of ROA. Non-ROA and ROA participants with fluctuating and persistent knee pain had increased cartilage volume loss compared with those with no pain (p for trend ≤ 0.01). Non-ROA participants with fluctuating knee pain had increased risk of incident ROA (OR 1.62, 95% CI 1.04–2.54), corresponding to a number needed to harm of 19.5. In ROA the risk of progressive ROA increased in participants with persistent knee pain (OR 1.82, 95% CI 1.28–2.60), corresponding to a number needed to harm of 9.6.

Conclusions

Knee pain over 1 year predicted accelerated cartilage volume loss and increased risk of incident and progressive ROA. Early management of knee pain and controlling knee pain over time by targeting the underlying mechanisms may be important for preserving knee structure and reducing the burden of knee OA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1751-4) contains supplementary material, which is available to authorized users.

MRI-detected osteophytes of the knee: natural history and structural correlates of change

Backgroud

The natural history of semi-quantitative magnetic resonance imaging (MRI)-detected osteophytes (MRI-detected OPs) has not been described and it is unknown whether knee structural abnormalities can predict MRI-detected OP change over time. Thus, the aim of current study is to describe the natural history of knee MRI-detected OP, and to determine if knee structural abnormalities are associated with change of MRI-detected OP in a longitudinal study of older adults.

Methods

Randomly selected older adults (n = 837, mean age 63 years) had MRI at baseline and 413 of them had MRI 2.6 years later to measure MRI-detected OP, cartilage defects, cartilage volume, bone marrow lesions (BMLs), meniscal extrusion, infrapatellar fat pad (IPFP) quality score/maximum area and effusion-synovitis.

Results

Over 2.6 years, average MRI-detected OP score increased significantly in all compartments. The total MRI-detected OP score remained stable in 53% of participants, worsened (≥ 1-point increase) in 46% and decreased in 1%. Baseline cartilage defects (RR, 1.25–1.35), BMLs (RR, 1.16–1.17), meniscal extrusion (RR, 1.22–1.33) and IPFP quality score (RR, 1.08–1.20) site-specifically and independently predicted an increase in MRI-detected OP (p values all ≤ 0.05), after adjustment for covariates. Presence of IPFP abnormality was significantly associated with increased MRI-detected OPs but became non-significant after adjustment for other structural abnormalities. Total (RR, 1.27) and suprapatellar pouch effusion-synovitis (RR, 1.22) were both associated with increased MRI-detected OPs in the lateral compartment only (both p < 0.04).

Conclusion

Knee MRI-detected OPs are common in older adults and are likely to progress. The association between baseline structural abnormalities and worsening MRI-detected OPs suggest MRI-detected OP could be a consequence of multiple knee structural abnormalities.

Structural abnormalities detected by knee magnetic resonance imaging are common in middle-aged subjects with and without risk factors for osteoarthritis

Background and purpose - Few data are available regarding structural changes present in knees without radiographically evident osteoarthritis (OA). We evaluated the prevalence of findings suggestive of knee OA by magnetic resonance imaging (MRI) in middle-aged subjects without radiographic OA with or without OA risk factors. Patients and methods - 340 subjects from the Osteoarthritis Initiative, aged 45-55 years (51% women) with Kellgren-Lawrence grade 0 in both knees, who had 3T knee MR images were eligible. 294 subjects had risk factors and 46 were without risk factors. MR images were assessed using the MOAKS scoring system. Results - At least 1 MR-detected feature was found in 96% (283/294) of subjects with risk factors and in 87% (40/46) of those without. Cartilage damage (82%), bone marrow lesions (60%), osteophytes (45%), meniscal body extrusion (32%), and synovitis-effusion (29%) were the most common findings in subjects with risk factors, while cartilage damage (67%), osteophytes (46%), meniscal body extrusion (37%), and bone marrow lesions (35%) were most common in subjects without. The prevalence of any abnormality was higher in subjects with OA risk factors than in subjects without (prevalence ratio adjusted for age and sex 1.3 [95% CI 1.1-1.6]), so was prevalence of subchondral cysts and bone marrow lesions. MR-detected structural changes were more frequent in patellofemoral joints. Interpretation - Our findings highlight the great challenge in distinguishing pathological features of early knee OA from what could be considered part of "normal ageing." Bone marrow lesions were more frequently found in subjects with multiple OA risk factors.

Impact of oral osteoarthritis therapy usage among other risk factors on knee replacement: a nested case-control study using the Osteoarthritis Initiative cohort

BACKGROUND

The aim of this study was to measure the association between exposure to commonly used oral osteoarthritis (OA) therapies and relevant confounding risk factors on the occurrence of knee replacement (KR), using the Osteoarthritis Initiative (OAI) database.

METHODS

In this nested case-control design study, participants who had a KR after cohort entry were defined as "cases" and were matched with up to four controls for age, gender, income, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, Kellgren-Lawrence grade, and duration of follow up. Exposure to oral OA therapies (acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), cyclooxygenase-2 (COX-2) inhibitors, narcotics, and glucosamine/chondroitin sulfate) was determined within the 3 years prior to the date of the KR. Conditional regression analyses were performed to estimate the association between KR and exposure to oral OA therapies and other potential confounding risk factors.

RESULTS

A total of 218 participants who underwent a KR (cases) were matched to 540 controls. The median time to KR was 4.3 years among cases. The majority in both groups were Caucasian with mean age of 69 years and 61% were female. Numerically, cases were more exposed to acetaminophen, NSAIDs, and COX-2 inhibitors. Exposure to narcotics and glucosamine/chondroitin sulfate was relatively similar between cases and controls. No significant association was found between the occurrence of KR and exposure to any of the oral OA therapies within the 3 years prior to KR. A significantly higher occurrence of KR was found in Caucasian subjects (OR 1.84; 95% CI, 1.13-2.99; p = 0.015) and subjects with body mass index (BMI) ≥ 27 kg/m² (OR 1.65; 95% CI, 1.06-2.58; p = 0.027).

CONCLUSION

This study provides evidence that the main risk factors leading to KR are disease severity, symptoms and high BMI. Importantly, exposure to oral OA therapies was not associated with the occurrence of KR.

A protocol for a multicentre, randomised, double-blind, placebo-controlled trial to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change and knee pain over 24 months in knee osteoarthritis patients - ZAP2

BACKGROUND

Bisphosphonates are a class of drugs that slow bone loss and are a promising candidate to treat knee osteoarthritis (OA) patients. In a pilot study, we demonstrated that zoledronic acid reduced knee pain and size of subchondral bone marrow lesions (BMLs) over 6 months in knee OA patients with significant knee pain and BMLs. A longer, larger study is required to assess whether decreases in BML size will translate to reductions in cartilage loss over time. We are currently conducting a multicentre, randomised, double-blind, placebo-controlled trial over 24 months that aims to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change (assessed using magnetic resonance imaging (MRI)) and knee pain in knee OA patients.

METHODS

Two hundred sixty-four patients with clinical knee OA, significant knee pain and subchondral BMLs present on MRI will be recruited in Hobart, Melbourne, Sydney and Adelaide. They will be randomly allocated to the two arms of the study, receiving an annual identical intravenous infusion of either 100 mL of fluid containing zoledronic acid (5 mg/100 mL) or placebo (0.9% NaCl 100 mL), at baseline and 1 year later. MRI of the study knee will be performed at screening, month 6 and 24. Knee structure, symptoms and function will be assessed using validated methods. The primary outcome is absolute change in tibiofemoral cartilage volume (mm3) over 24 months. Secondary outcomes include improvement in knee pain over 3, 6, 12, 18, and 24 months and reductions in BML size over 6 and 24 months. The primary analyses will be intention-to-treat analyses of primary and secondary outcomes. Per protocol analyses will be performed as the secondary analyses.

DISCUSSION

This study will provide high-quality evidence to assess whether zoledronic acid has a novel disease modifying effect in OA by slowing cartilage loss and reducing pain. If zoledronic acid proves effective, it suggests great potential for cost savings through a delay or reduced need for joint replacement surgery, and potential for great improvements in quality of life for OA suffers.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12613000039785 , registered on 14 January 2013.

Learning-Based Cost Functions for 3-D and 4-D Multi-Surface Multi-Object Segmentation of Knee MRI: Data From the Osteoarthritis Initiative

A fully automated knee magnetic resonance imaging (MRI) segmentation method to study osteoarthritis (OA) was developed using a novel hierarchical set of random forests (RF) classifiers to learn the appearance of cartilage regions and their boundaries. A neighborhood approximation forest is used first to provide contextual feature to the second-level RF classifier that also considers local features and produces location-specific costs for the layered optimal graph image segmentation of multiple objects and surfaces (LOGISMOS) framework. Double-echo steady state MRIs used in this paper originated from the OA Initiative study. Trained on 34 MRIs with varying degrees of OA, the performance of the learning-based method tested on 108 MRIs showed significant reduction in segmentation errors ( ) compared with the conventional gradient-based and single-stage RF-learned costs. The 3-D LOGISMOS was extended to longitudinal-3-D (4-D) to simultaneously segment multiple follow-up visits of the same patient. As such, data from all time-points of the temporal sequence contribute information to a single optimal solution that utilizes both spatial 3-D and temporal contexts. 4-D LOGISMOS validation on 108 MRIs from baseline, and 12 month follow-up scans of 54 patients showed significant reduction in segmentation errors ( ) compared with 3-D. Finally, the potential of 4-D LOGISMOS was further explored on the same 54 patients using five annual follow-up scans demonstrating a significant improvement of measuring cartilage thickness ( ) compared with the sequential 3-D approach.

Joint problems arising from lack of repair mechanisms: can cannabinoids help?

Osteoarthritis (OA) is the most common disease of joints, which are complex organs where cartilage, bone and synovium cooperate to allow a range of movements. During progression of the disease, the function of all three main components is jeopardized. Nevertheless, the involvement of each tissue in OA development is still not established and is the topic of the present review. The OA therapies available are symptomatic, largely targeting pain management rather than disease progression. The strong need to develop a treatment for cartilage degeneration, bone deformation and synovial inflammation has led to research on the involvement of the endocannabinoid system in the development of OA. The current review discusses the research on this topic to date and notes the advantages of exploiting endocannabinoid system modulation for cartilage, bone and synovium homeostasis, which could prevent the further progression of OA. LINKED ARTICLES: This article is part of a themed section on 8^th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.

Medial meniscal extrusion: Detection, evaluation and clinical implications

The menisci play an important role in knee kinematics. Their unique anatomy allows them to channel forces generated during knee movements through the larger tibio-femoral condylar surfaces while simultaneously resisting deleterious hoop stresses. Although physiologic meniscal extrusion occurs with every knee joint movement, pathologic meniscal extrusion subjects the knee to persistent and excessive load transmission. This renders the knee structures susceptible to injury or exacerbates worsening of existing knee joint internal derangement. Detection and quantification of meniscus extrusion is important given its association with underlying pathological processes and internal derangements such as cartilage loss, osteoarthritis and meniscal tears. The medial and lateral menisci vary in size, attachments and load transmission, and the medial meniscus is more susceptible to injury. In this article, the authors illustrate the role of meniscus kinematics, and the identification and quantification of medial meniscal extrusion. Multimodality imaging appearances and implications of presence of medial meniscal extrusion in different knee joint pathologies are discussed with review of the relevant literature.

Determination of knee cartilage volume and surface area in beagle dogs: a pilot study

BACKGROUND

The objective of this study was to determine the cartilage volume and surface area of male and female Beagle dog knees using 3D (3 dimensional) reconstructed MRI images.

METHODS

Six Beagle Dogs (Canis familiaris) (3 males and 3 females) of 10-18 months old and weighing between 7.2 and 17.1 kg underwent a MRI evaluation of both knees. The data acquired allowed a 3D reconstruction of the knee and measurement of the cartilage volume and surface area.

RESULTS

Mean knee cartilage volume (averaged over the right and left knees) of animals between 7.2 and 17.1 kg ranged from 319.7 to 647.3 mm3; while the mean knee cartilage surface area ranged from 427.14 to 757.2 mm2. There was evidence of both knee volume and surface area increasing linearly with animal bodyweight.

CONCLUSIONS

The cartilage volume and surface area of the Beagle dog appears to correlate significantly with body weight. This study provides a reference base for future studies investigating cartilage related pathology such as osteoarthritis.

Levels of serum biomarkers from a two-year multicentre trial are associated with treatment response on knee osteoarthritis cartilage loss as assessed by magnetic resonance imaging: an exploratory study

Background

There is an obvious need to identify biomarkers that could predict patient response to an osteoarthritis (OA) treatment. This post hoc study explored in a 2-year randomized controlled trial in patients with knee OA, the likelihood of some serum biomarkers to be associated with a better response to chondroitin sulfate in reducing cartilage volume loss.

Methods

Eight biomarkers were studied: hyaluronic acid (HA), C reactive protein (CRP), adipsin, leptin, N-terminal propeptide of collagen IIα (PIIANP), C-terminal crosslinked telopeptide of type I collagen (CTX-1), matrix metalloproteinase-1 (MMP-1), and MMP-3. Patients were treated with chondroitin sulfate (1200 mg/day; n = 57) or celecoxib (200 mg/day; n = 62). Serum biomarkers were measured at baseline. The cartilage volume at baseline and its loss at 2 years were assessed by quantitative magnetic resonance imaging (MRI). Statistical analysis included analysis of covariance.

Results

As data from the original MOSAIC trial showed no differences in cartilage volume and loss in the lateral compartment of the knee joint between the two treatment groups in any comparison, only the medial compartment and its subregions were studied. Stratification according to the median biomarker levels was used to discriminate treatment effect. In patients with levels of biomarkers of inflammation (HA, leptin and adipsin) lower than the median, those treated with chondroitin sulfate demonstrated less cartilage volume loss in the medial compartment, condyle, and plateau (p ≤ 0.047). In contrast, patients treated with chondroitin sulfate with higher levels of MMP-1 and MMP-3, biomarkers of cartilage catabolism, had less cartilage volume loss in the medial compartment, condyle, and plateau (p ≤ 0.050). Patients with higher levels of PIIANP and CTX-1, biomarkers related to collagen anabolism and bone catabolism, respectively, had reduced cartilage volume loss in the medial condyle (p ≤ 0.026) in the chondroitin sulfate group.

Conclusion

This study is suggestive of a potentially greater response to chondroitin sulfate treatment on cartilage volume loss in patients with knee OA with low level of inflammation and/or greater level of cartilage catabolism.

Trial registration

This is a post hoc study. Original trial registration: ClinicalTrials.gov, NCT01354145. Registered on 13 May 2011. 

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1377-y) contains supplementary material, which is available to authorized users.

Meniscal extrusion and bone marrow lesions are associated with incident and progressive knee osteoarthritis

OBJECTIVE

Whether meniscal extrusion and bone marrow lesions (BMLs) are independently associated with the risk of knee osteoarthritis (OA) is unknown.

METHODS

Data was extracted from the Osteoarthritis Initiative (OAI) cohort. Participants were grouped according to the absence (Kellgren-Lawrence (KL) grade ≤ 1, n = 2120) or presence (KL ≥ 2, n = 2249) of radiographic OA (ROA). Baseline meniscal extrusion and tibial BMLs were assessed. Tibial plateau cartilage volume was assessed at baseline and 72 months, while radiographic disease was assessed at baseline and 48 months. Total knee replacement (TKR) was assessed at 72 months.

RESULTS

In those with ROA, the presence of a baseline meniscal extrusion (independent of BMLs) was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.5%; lateral: -2.6%/annum vs -1.6%; both P < 0.001), progressive ROA and TKR (Odds ratio (OR) range 1.4-1.8; 95% CI range 1.1-2.9). The presence of a baseline BML was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.6%; lateral: -1.9%/annum vs -1.6%; P ≤ 0.02), progressive ROA and joint replacement (OR range 1.5-2.4; 95% CI range 1.1-3.4). In those with no ROA, a baseline medial meniscal extrusion was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.2%, P < 0.001), and a baseline medial BML with incident ROA (OR 1.7, 95% CI 1.1 to 2.9).

CONCLUSIONS

The presence of baseline meniscal extrusion and BMLs are associated with incident and progressive knee of each other (OA) and represent important structural targets for the treatment and prevention of knee OA.

EULAR recommendations for the use of imaging in the clinical management of peripheral joint osteoarthritis

The increased information provided by modern imaging has led to its more extensive use. Our aim was to develop evidence-based recommendations for the use of imaging in the clinical management of the most common arthropathy, osteoarthritis (OA). A task force (including rheumatologists, radiologists, methodologists, primary care doctors and patients) from nine countries defined 10 questions on the role of imaging in OA to support a systematic literature review (SLR). Joints of interest were the knee, hip, hand and foot; imaging modalities included conventional radiography (CR), MRI, ultrasonography, CT and nuclear medicine. PubMed and EMBASE were searched. The evidence was presented to the task force who subsequently developed the recommendations. The strength of agreement for each recommendation was assessed. 17 011 references were identified from which 390 studies were included in the SLR. Seven recommendations were produced, covering the lack of need for diagnostic imaging in patients with typical symptoms; the role of imaging in differential diagnosis; the lack of benefit in monitoring when no therapeutic modification is related, though consideration is required when unexpected clinical deterioration occurs; CR as the first-choice imaging modality; consideration of how to correctly acquire images and the role of imaging in guiding local injections. Recommendations for future research were also developed based on gaps in evidence, such as the use of imaging in identifying therapeutic targets, and demonstrating the added value of imaging. These evidence-based recommendations and related research agenda provide the basis for sensible use of imaging in routine clinical assessment of people with OA.

A Phase I clinical trial of the knee to assess the correlation of gagCEST MRI, delayed gadolinium-enhanced MRI of cartilage and T2 mapping

PURPOSE

Osteoarthritis (OA) is associated with the loss of glycosaminoglycan (GAG) during disease progression, which can be detected by glycosaminoglycan chemical exchange-dependent saturation transfer (gagCEST) MRI. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is considered one of the standard methods for GAG quantification in vivo. This Phase I study assessed the correlation between gagCEST MRI and dGEMRIC in determining cartilage GAG concentration. Standard T2 mapping was used as a comparator with the two other methods.

MATERIALS AND METHODS

Eight athletic volunteers with no known knee diseases were recruited in this study. The sagittal images of both knees in each volunteer were obtained by a 3T MRI system. GAG concentration was calculated based on fixed charge density (FCD) within articular cartilage as calculated by T1 values obtained from dGEMRIC sequences. Magnetization transfer ratio asymmetry (MTR_asym) of the CEST spectrum at 1ppm was determined with gagCEST MRI. T2 values were calculated using a multi-echo turbo spin echo (TSE) sequence. The Pearson correlations among MTR_asym were calculated from gagCEST analysis.

RESULTS

There was moderate correlation (correlation coefficient r=0.55) between dGEMRIC and gagCEST MRI results. T2 had a low correlation (r=-0.30) with gagCEST and no correlation with dGEMRIC (r=0.003). Both gagCEST and dGEMRIC were able to distinguish between high GAG concentration cartilage compartments (higher than 210mM) and low GAG cartilage compartments (lower than 210mM).

CONCLUSION

dGEMRIC was shown to be a more accurate and sensitive clinical imaging tool in evaluating cartilage GAG levels in vivo. While GagCEST showed less sensitivity to GAG concentration variations than dGEMRIC, further improvements may yet enable gagCEST to be a clinically robust methodology.