Association of magnetic resonance imaging-based knee cartilage T2 measurements and focal knee lesions with knee pain: data from the Osteoarthritis Initiative

Assessment of articular cartilage degradation in response to an impact injury using µMRI

PURPOSE

Degradation of articular cartilage (AC) due to injury to the knee joint may initiate post-traumatic osteoarthritis (PTOA). Failure to diagnose the onset of the disease at an early stage makes the cure ineffective for PTOA. This study investigated the consequences of a mechanical injury to the knee in a rabbit model using microscopic magnetic resonance imaging (µMRI) at high resolution.

MATERIALS AND METHODS

A mechanical injury was induced to the knee joints of 12 rabbits. Cartilage blocks were extracted from the non-impacted and impacted knee joints after 2 and 14 weeks post-impact. The specimens were studied using µMRI T2 relaxation and inductively coupled plasma analysis to determine the early degradation of the articular cartilage.

RESULTS

The data established a connection between T2 relaxation time and the early progression of knee PTOA after an impact injury. T2 values were found to be higher in the impacted cartilage at both 2 and 14 weeks, in particular, T2-55° values in the impacted samples displayed a significant rise of 6.93% after 2 weeks and 20.02% after 14 weeks. Lower glycosaminoglycan measurement and higher water content in the impacted cartilage confirmed the µMRI results.

CONCLUSIONS

This µMRI T2 study was able to detect cartilage damage in the impacted knees. In addition, greater degradation in the affected knees at 14 weeks than at 2 weeks indicated the progressive nature of cartilage deterioration over time. The µMRI results were in accord with the biochemical analysis, indicating the detection of early structural damage in the cartilage.

Biomarkers of Cartilage Composition

Magnetic resonance imaging (MRI) has significantly advanced the understanding of osteoarthritis (OA) because it enables visualization of noncalcified tissues. Cartilage is avascular and nurtured by diffusion, so it has a very low turnover and limited capabilities of repair. Consequently, prevention of structural and detection of premorphological damage is key in maintaining cartilage health. The integrity of cartilage composition and ultrastructure determines its mechanical properties but is not accessible to morphological imaging. Therefore, various techniques of compositional MRI with and without use of intravenous contrast medium have been developed. Spin-spin relaxation time (T2) and spin-lattice relaxation time constant in rotating frame (T1rho) mapping, the most studied cartilage biomarkers, were included in the recent standardization effort by the Quantitative Imaging Biomarkers Alliance (QIBA) that aims to make compositional MRI of cartilage clinically feasible and comparable. Additional techniques that are less frequently used include ultrashort echo time with T2*, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), glycosaminoglycan concentration by chemical exchange-dependent saturation transfer (gagCEST), sodium imaging, and diffusion-weighted MRI.

MRI-based T1rho and T2 cartilage compositional imaging in osteoarthritis: what have we learned and what is needed to apply it clinically and in a trial setting?

Cartilage MRI-based T1rho and T2 compositional measurements have been developed to characterize cartilage matrix quality and diagnose cartilage damage before irreversible defects are found, allowing intervention at an early, potentially reversible disease stage. Over the last 2 decades, this technology was investigated in numerous studies and was validated using specimen studies and arthroscopy; and longitudinal studies documented its ability to predict progression of degenerative disease and radiographic osteoarthritis (OA). While T1rho and T2 measurements have shown promise in early disease stages, several hurdles have been encountered to apply this technology clinically. These include (i) challenges with cartilage segmentation, (ii) long image acquisition times, (iii) a lack of standardization of imaging, and (iv) an absence of reference databases and definitions of abnormal cut-off values. Progress has been made by developing deep-learning based automatic cartilage segmentation and faster imaging methods, enabling the feasibility of T1rho and T2 imaging for clinical and scientific trial applications. Also, the Radiological Society of North America (RSNA) Quantitative Imaging Biomarker Alliance mechanism was used to establish standardized profiles for compositional T1rho and T2 imaging, and multi-center feasibility testing is work in progress. The last hurdles are the development of reference databases and establishing a definition of normal versus abnormal cartilage T1rho and T2 values. Finally, effective treatments for prevention and slowing progression of OA are required in order to establish T1rho and T2 as imaging biomarkers for initiating and monitoring therapies, analogous to the role of dual X-ray absorptiometry (DXA) bone mineral density measurements in the management of osteoporosis. KEY POINTS: • T1rho and T2 cartilage measurements have been validated in characterizing cartilage degenerative change using histology and arthroscopy as a reference. • They have also been shown to predict progression of cartilage degeneration and incidence of radiographic OA. • Advances have been made to facilitate clinical and trial application of T1rho and T2 by improved standardization of imaging and by establishing deep learning-based automatic cartilage segmentation. • Effective treatments with disease-modifying OA specific drugs may establish T1rho and T2 cartilage compositional measurements as biomarkers to initiate and monitor treatment.

Advances in osteoarthritis imaging

PURPOSE OF REVIEW

Imaging plays a pivotal role for diagnosis, follow-up and stratification of osteoarthritis patients in clinical trials and research. We aim to present an overview of currently available and emerging imaging techniques for osteoarthritis assessment and provide insight into relevant benefits and pitfalls of the different modalities.

RECENT FINDINGS

Although radiography is considered sufficient for a structural diagnosis of osteoarthritis and is commonly used to define eligibility of patients for participation in clinical trials, it has inherent limitations based on the projectional nature of the technique and inherent challenges regarding reproducibility in longitudinal assessment. MRI has changed our understanding of the disease from 'wear and tear' of cartilage to a whole organ disorder. MRI assessment of structural changes of osteoarthritis includes semi-quantitative, quantitative and compositional evaluation. Ultrasound is helpful in evaluating the degree of synovitis and has value in the assessment particularly of the patella-femoral joint. Recent development of computed tomography technology including weight-bearing systems has led to broader application of this technology in a research context.

SUMMARY

Advances in MRI technology have resulted in a significant improvement in understanding osteoarthritis as a multitissue disease.

Osteophytes mediate the associations between cartilage morphology and changes in knee symptoms in patients with knee osteoarthritis

Aims

To investigate whether the associations between cartilage defects and cartilage volumes with changes in knee symptoms were mediated by osteophytes.

Methods

Data from the Vitamin D Effects on Osteoarthritis (VIDEO) study were analyzed as a cohort. The Western Ontario and McMaster Universities Osteoarthritis Index was used to assess knee symptoms at baseline and follow-up. Osteophytes, cartilage defects, and cartilage volumes were measured using magnetic resonance imaging at baseline. Associations between cartilage morphology and changes in knee symptoms were assessed using linear regression models, and mediation analysis was used to test whether these associations were mediated by osteophytes.

Results

A total of 334 participants (aged 50 to 79 years) with symptomatic knee osteoarthritis were included in the analysis. Cartilage defects were significantly associated with change in total knee pain, change in weight-bearing pain, and change in non-weight-bearing pain after adjustment for age, sex, body mass index, and intervention. Cartilage volume was significantly associated with change in weight-bearing pain and change in physical dysfunction after adjustment. Lateral tibiofemoral and patellar osteophyte mediated the associations of cartilage defects with change in total knee pain (49–55%) and change in weight-bearing pain (61–62%) and the association of cartilage volume with change in weight-bearing pain (27–30%) and dysfunction (24–25%). Both cartilage defects and cartilage volume had no direct effects on change in knee symptoms.

Conclusions

The significant associations between cartilage morphology and changes in knee symptoms were indirect and were partly mediated by osteophytes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02905-8.

Sandwich Technique for Large Osteochondral Lesions of the Knee

OBJECTIVE

To evaluate whether a sandwich technique procedure for large osteochondral lesions (OCL) of the medial femur condyle reduces clinical symptoms and improves activity level as well as to assess repair tissue integration on MRI over 2 years.

DESIGN

Twenty-one patients (median age: 29 years, 18-44 years) who received matrix-associated autologous chondrocyte transplantation (MACT) combined with cancellous bone grafting at the medial femur condyle in a 1-step procedure were prospectively included. Patients were evaluated before surgery (baseline) as well as 3, 6, 12, and 24 months postoperatively, including clinical evaluation, Lysholm score, Tegner Activity Rating Scale, and MRI with Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score and a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS).

RESULTS

Seventeen patients were available for the 24-month (final) follow-up (4 dropouts). Lysholm significantly improved from 48 preoperatively stepwise to 95 at final follow-up (P < 0.05). Tegner improvement from 2.5 at baseline to 4.0 at final follow-up was not significant (P = 1.0). MOCART score improved significantly and stepwise from 65 at 3 months to 90 at 24 months (P < 0.05). Total WORMS improved from 14.5 at surgery to 7.0 after 24 months (P < 0.05). Body mass index and defect size at surgery correlated with total WORMS at final follow-up (P < 0.05) but did not correlate with clinical scores or defect filling.

CONCLUSION

MACT combined with cancellous bone grafting at the medial femoral condyle reduces symptoms continuously over 2 years. A 1-step procedure may reduce perioperative morbidity. However, despite improvements, patients' activity levels remain low, even 2 years after surgery.

The Effect of Lesion Size on Pain and Function in Patients Scheduled for Cartilage Surgery of the Knee

OBJECTIVE

Despite an increased interest in treatment options for cartilage lesions of the knee, the relationship between lesion characteristics and the symptoms they elicit is not well understood. We evaluated the relationship between lesion characteristics and the patient-reported outcome measures (PROMs) and compared this with symptoms reported by patients scheduled for knee ligament reconstruction and knee arthroplasty.

DESIGN

Preoperative data, including Lysholm score and The Knee Injury and Osteoarthritis Outcome Score (KOOS), in 90 consecutive patients scheduled for surgery for symptomatic isolated cartilage lesions were prospectively collected.

RESULT

The patients had a mean age of 33.2 years. There were 62 (69%) males. There was no statistically significant difference in PROMs between patients with cartilage lesions smaller or larger than 2 cm², except for the KOOS subscale symptoms, with patients with smaller lesions reporting higher scores, 62.8 (95% confidence interval [CI] 58.3-67.3) vs. 51.9 (95% CI 45.5-58.4), P = 0.005. There was a small correlation between lesion size and Lysholm score. However, when adjusted for age, sex, body mass index, and lesion localization, this effect was not statistically significant. The International Cartilage Regeneration & Joint Preservation Society grade did not affect preoperative PROMs. Cartilage patients reported worse preoperative symptoms than patients scheduled for knee ligament reconstruction, and approaching the symptoms reported by patients scheduled for knee arthroplasty.

CONCLUSION

The size, depth, and location of cartilage lesions have little impact on the symptoms experienced by the patients. Cartilage patients have comparable symptoms to patients scheduled for knee arthroplasty.

Imaging of Osteoarthritis of the Knee

Knee osteoarthritis is rising in prevalence, and more imaging studies are being requested to evaluate these patients. Although conventional radiographs of the knee are the most widely requested and available studies, other imaging modalities such as MRI, CT, and ultrasound may also be used. This article reviews commonly used imaging modalities, advantages and limitations of each, and their clinical applicability in diagnosing and monitoring knee osteoarthritis. New and advanced imaging techniques are also discussed as possible methods of early diagnosis and improved understanding of osteoarthritis pathophysiology.

Meniscal anterior and posterior horn heights are associated with MRI-defined knee structural abnormalities in middle-aged and elderly patients with symptomatic knee osteoarthritis

Background

Meniscal morphological changes are associated with knee OA. However, the correlation of meniscal height and OA-related knee structural abnormalities is still not well understood. The purpose of present study is to investigate whether and how meniscal anterior and posterior horn heights are associated with structural abnormalities in knees with symptomatic OA.

Methods

Our sample consisted of 106 patients (61 female, aged 40–73 years) with symptomatic knee OA. Kellgren-Lawrence system was used for radiographic evaluation. On sagittal sequence, medial meniscal posterior horn height (MPH), lateral meniscal anterior horn height (LAH) and lateral meniscal posterior horn height (LPH) were measured on the middle slice through the medial/lateral compartment. Knee structural abnormalities were assessed using the modified whole-organ magnetic resonance imaging score (WORMS). Associations between meniscal anterior and posterior horn heights and knee structural abnormalities were assessed using linear regression analysis.

Results

Higher MPH was significantly associated with higher WORMS score for medial meniscal anterior horn lesion (P = 0.016) but did not have a statistical association with other WORMS parameters. Increased LAH was statistically correlated with decreased WORMS scores for lateral compartmental cartilage lesions (P = 0.001–0.004) and lateral compartmental bone marrow edema patterns (BMEPs) (P = 0.021–0.027). Moreover, LPH was negatively associated with WORMS scores for lateral compartmental cartilage lesions (P = 0.007–0.041) and lateral compartmental BMEPs (P = 0.022–0.044). Additionally, higher MPH was statistically associated with lower trochlea cartilage WORMS score and higher LAH was significantly correlated with higher WORMS score for trochlea subarticular cysts.

Conclusions

Changes of LAH and LPH were inversely associated with the severity of lateral compartmental cartilage lesions and BMEPs, while higher MPH was only significantly correlated with more severe medial meniscal anterior horn lesions. Besides, MPH and LAH were also significantly associated with patellofemoral structural abnormalities. The present study provided novel information for understanding the role of meniscal morphological changes in knee OA, which would be helpful in identifying and evaluating knees with or at risks for OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05143-w.

AI MSK clinical applications: cartilage and osteoarthritis

The advancements of artificial intelligence (AI) for osteoarthritis (OA) applications have been rapid in recent years, particularly innovations of deep learning for image classification, lesion detection, cartilage segmentation, and prediction modeling of future knee OA development. This review article focuses on AI applications in OA research, first describing machine learning (ML) techniques and workflow, followed by how these algorithms are used for OA classification tasks through imaging and non-imaging-based ML models. Deep learning applications for OA research, including analysis of both radiographs for automatic detection of OA severity, and MR images for detection of cartilage/meniscus lesions and cartilage segmentation for automatic T₂ quantification will be described. In addition, information on ML models that identify individuals at high risk of OA development will be provided. The future vision of machine learning applications in imaging of OA and cartilage hinges on implementation of AI for optimizing imaging protocols, quantitative assessment of cartilage, and automated analysis of disease burden yielding a faster and more efficient workflow for a radiologist with a higher level of reproducibility and precision. It may also provide risk assessment tools for individual patients, which is an integral part of precision medicine.

Machine learning to predict incident radiographic knee osteoarthritis over 8 Years using combined MR imaging features, demographics, and clinical factors: data from the Osteoarthritis Initiative

OBJECTIVE

To develop a machine learning-based prediction model for incident radiographic osteoarthritis (OA) of the knee over 8 years using MRI-based cartilage biochemical composition and knee joint structure, demographics, and clinical predictors including muscle strength and symptoms.

DESIGN

Individuals (n = 1,044) with baseline Kellgren Lawrence (KL) grade 0-1 in the right knee from the Osteoarthritis Initiative database were analyzed. 3T MRI at baseline was used to quantify knee cartilage T₂, and Whole-Organ Magnetic Resonance Imaging Scores (WORMS) were obtained for cartilage, meniscus, and bone marrow. The outcome was set as true if a subject developed KL grade 2-4 OA in the right knee over 8 years (n = 183) and false if the subject remained at KL 0-1 over 8 years (n = 861). We developed and compared three models: Model 1: 112 predictors based on OA risk factors; Model 2: top ten predictors based on feature importance score from Model 1 and clinical relevance; Model 3: Model 2 without the imaging predictors. We compared the models using the area under the ROC curve derived from hold-out data.

RESULTS

The 10-predictor model (Model 2, that includes cartilage and meniscus WORMS scores and cartilage T₂) had a slightly lower AUC (0.772) compared to the model with 112 predictors (Model 1: AUC = 0.792, p = 0.739); and had a significantly higher AUC compared to the model without MR imaging predictors (Model 3, AUC = 0.669, p = 0.011).

CONCLUSIONS

A 10-predictor model including MRI parameters coupled with demographics, symptoms, muscle, and physical activity scores provides good prediction of incident radiographic OA over 8 years.

Investigating the Association of Metabolic Biomarkers With Knee Cartilage Composition and Structural Abnormalities Using MRI: A Pilot Study

OBJECTIVE

The goal of this study was to explore the metabolic syndrome-associated phenotype of osteoarthritis by investigating the cross-sectional associations of glycemic markers and serum lipids with knee cartilage composition and structural abnormalities in middle-aged adults.

DESIGN

Twenty participants between 40 to 70 years of age with Kellgren-Lawrence score 0-1 in at least one knee were recruited at a single center. Knee cartilage composition was assessed using 3.0 T cartilage T₂ and T_1ρ mapping. Evaluation of structural knee abnormalities was performed using the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). Linear regression was used to assess the associations of standardized fasting glucose (FG), hemoglobin A1c (HbA1c), insulin, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), non-HDL cholesterol, and triglycerides with cartilage T₂ and T_1ρ as well as WORMS subscores, adjusting for body mass index.

RESULTS

Higher FG and higher HbA1c were associated with higher WORMS meniscus sum (beta coefficient 1.31 [95% confidence interval (CI): 0.57, 2.05], P = 0.002 per standard deviation [SD] increase in FG; beta coefficient 0.90 [95% CI: 0.07, 1.73], P = 0.035 per SD increase in HbA1c). Also, higher total cholesterol and higher non-HDL cholesterol were associated with higher WORMS cartilage sum (beta coefficient 0.94 [95% CI: 0.01, 1.86], P = 0.048 per SD increase in total cholesterol; beta coefficient 1.05 [95% CI: 0.14, 1.96], P = 0.03 per SD increase in non-HDL cholesterol).

CONCLUSIONS

Higher FG and HbA1c were associated with increased meniscal degeneration while higher total and non-HDL cholesterol were associated with increased cartilage degeneration.

Meniscal Root Tears and Extrusion Are Significantly Associated with the Development of Accelerated Knee Osteoarthritis: Data from the Osteoarthritis Initiative

OBJECTIVE

To identify joint structural risk factors, measured using quantitative compositional and semiquantitative magnetic resonance imaging (MRI) scoring, associated with the development of accelerated knee osteoarthritis (AKOA) compared with a more normal rate of knee osteoarthritis (OA) development.

DESIGN

From the Osteoarthritis Initiative we selected knees with no radiographic OA (Kellgren-Lawrence grade [KL] 0/1) that developed advanced-stage OA (KL 3/4; AKOA) within a 4-year timeframe and a comparison group with a more normal rate of OA development (KL 0/1 to KL 2 in 4 years). MRIs at the beginning of the 4-year timeframe were assessed for cartilage T2 values and structural abnormalities using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). Associations of MRI findings with AKOA versus normal OA were assessed using multivariable logistic regression models.

RESULTS

A total of 106 AKOA and 168 subjects with normal OA development were included. Mean cartilage T2 values were not significantly associated with AKOA (odds ratio [OR] 1.06; 95% confidence interval [CI] 0.82-1.36). Risk factors for AKOA development included higher meniscus maximum scores (OR 1.37; 95% CI 1.11-1.68), presence of meniscal extrusion (OR 6.30; 95% CI 2.57-15.49), presence of root tears (OR 4.64; 95% CI 1.61-13.34), and higher medial tibia cartilage lesion scores (OR 1.96; 95% CI 1.19-3.24).

CONCLUSIONS

We identified meniscal damage, especially meniscal extrusion and meniscal root tears as risk factors for AKOA development. These findings contribute to identifying subjects at risk of AKOA at an early stage when preventative measures targeting modifiable risk factors such as meniscal repair surgery could still be effective.

Is Laminar Cartilage Composition as Determined by T2 Relaxometry Associated with Incident and Worsening of Cartilage or Bone Marrow Abnormalities?

OBJECTIVE

To test the hypothesis that superficial cartilage composition (T2) is associated with subsequent incidence or worsening of cartilage damage, and deep T2 with that of bone marrow lesions (BMLs) in knees without radiographic osteoarthritis (ROA).

DESIGN

A total of 201 knees from the Osteoarthritis Initiative without ROA were included: 78 from the healthy reference cohort, 60 without ROA but with risk factors, and 63 without ROA but with contralateral ROA. Year 1 (Y1) superficial and deep cartilage T2 were derived in the medial and lateral (weightbearing) femur (MF/LF) and tibia (MT/LT), using sagittal multiecho spin echo magnetic resonance images. Cartilage and BMLs were assessed in the medial (MFTJ) and lateral femorotibial joint (LFTJ) at Y1 and 3 years later. Binary logistic regression statistics were applied.

RESULTS

Incidence or worsening of cartilage damage was more frequent (MFTJ 15%, LFTJ 13%) than incidence or worsening of BMLs (6.0%, 4.5%). In knees with incident or worsening cartilage lesions in the MF and LT, deep layer T2 in the same plate was elevated (MF, 43.6 ± 4.0 vs. 41.3 ± 3.8 ms, P = 0.047; LT, 33.8 ± 2.3 vs. 32.0 ± 2.2 ms, P = 0.008) compared to those without. In knees with incident or worsening of BMLs in the LFTC and LT, superficial layer T2 was elevated (LFTJ, 49.6 ± 4.8 vs. 46.7 ± 3.1 ms; LT, 47.4 ± 4.9 vs. 44.0 ± 3.3 ms, both Ps = 0.04).

CONCLUSIONS

Contrary to our hypothesis, increased deep layer cartilage T2 was associated with subsequent worsening of cartilage damage, whereas superficial layer T2 was related to subsequent BML worsening. Yet, this relationship was observed in some, but not in all cartilage plates.

Reproducibility of an Automated Quantitative MRI Assessment of Low-Grade Knee Articular Cartilage Lesions

OBJECTIVE

The goal of this study was to assess the reproducibility of an automated knee cartilage segmentation of 21 cartilage regions with a model-based algorithm and to compare the results with manual segmentation.

DESIGN

Thirteen patients with low-grade femoral cartilage defects were included in the study and were scanned twice on a 7-T magnetic resonance imaging (MRI) scanner 8 days apart. A 3-dimensional double-echo steady-state (3D-DESS) sequence was used to acquire MR images for automated cartilage segmentation, and T2-mapping was performed using a 3D triple-echo steady-state (3D-TESS) sequence. Cartilage volume, thickness, and T2 and texture features were automatically extracted from each knee for each of the 21 subregions. DESS was used for manual cartilage segmentation and compared with automated segmentation using the Dice coefficient. The reproducibility of each variable was expressed using standard error of measurement (SEM) and smallest detectable change (SDC).

RESULTS

The Dice coefficient for the similarity between manual and automated segmentation ranged from 0.83 to 0.88 in different cartilage regions. Test-retest analysis of automated cartilage segmentation and automated quantitative parameter extraction revealed excellent reproducibility for volume measurement (mean SDC for all subregions of 85.6 mm³), for thickness detection (SDC = 0.16 mm) and also for T2 values (SDC = 2.38 ms) and most gray-level co-occurrence matrix features (SDC = 0.1 a.u.).

CONCLUSIONS

The proposed technique of automated knee cartilage evaluation based on the segmentation of 3D MR images and correlation with T2 mapping provides highly reproducible results and significantly reduces the segmentation effort required for the analysis of knee articular cartilage in longitudinal studies.

Uncovering associations between data-driven learned qMRI biomarkers and chronic pain

Knee pain is the most common and debilitating symptom of knee osteoarthritis (OA). While there is a perceived association between OA imaging biomarkers and pain, there are weak or conflicting findings for this relationship. This study uses Deep Learning (DL) models to elucidate associations between bone shape, cartilage thickness and T₂ relaxation times extracted from Magnetic Resonance Images (MRI) and chronic knee pain. Class Activation Maps (Grad-CAM) applied on the trained chronic pain DL models are used to evaluate the locations of features associated with presence and absence of pain. For the cartilage thickness biomarker, the presence of features sensitive for pain presence were generally located in the medial side, while the features specific for pain absence were generally located in the anterior lateral side. This suggests that the association of cartilage thickness and pain varies, requiring a more personalized averaging strategy. We propose a novel DL-guided definition for cartilage thickness spatial averaging based on Grad-CAM weights. We showed a significant improvement modeling chronic knee pain with the inclusion of the novel biomarker definition: likelihood ratio test p-values of 7.01 × 10^–33 and 1.93 × 10^–14 for DL-guided cartilage thickness averaging for the femur and tibia, respectively, compared to the cartilage thickness compartment averaging.

Relationship Between Magnetic Resonance Imaging Features and Knee Pain Over Six Years in Knees Without Radiographic Osteoarthritis at Baseline

Objective

To explore whether magnetic resonance imaging (MRI) features suggestive of knee osteoarthritis (OA) are associated with presence of knee pain in possible early‐stage OA development.

Methods

We included 294 participants from the Osteoarthritis Initiative (mean ± SD age 50 ± 3 years; 50% women) with baseline Kellgren/Lawrence grade of 0 in both knees, all of whom had received knee MRIs at 4 different time points over 6 years (baseline, 24, 48, and 72 months). Using a linear mixed model (knees matched within individuals), we studied whether MRI features (meniscal body extrusion [in mm], cartilage area loss [score 0–39], cartilage full thickness loss [range 0–16], osteophytes [range 0–29], meniscal integrity [range 0–10], bone marrow lesions [BMLs] including bone marrow cysts [range 0–20], Hoffa‐ or effusion‐synovitis [absent/present], and popliteal cysts [absent/present]) were associated with knee‐specific pain as reported on the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire using a 0–100 scale (worst to best).

Results

The differences in KOOS knee pain score for a knee with a 1 unit higher score on MRI were the following: meniscal extrusion –1.52 (95% confidence interval [95% CI] –2.35, –0.69); cartilage area loss –0.23 (95% CI –0.48, 0.02); cartilage full thickness loss –1.04 (95% CI –1.58, –0.50); osteophytes –0.32 (95% CI –0.61, –0.03); meniscal integrity –0.28 (95% CI –0.58, 0.02); BMLs including potential cysts –0.19 (95% CI –0.55, 0.16); synovitis 0.23 (95% CI –1.14, 1.60); and popliteal cysts 0.86 (95% CI –0.56, 2.29).

Conclusion

Meniscal extrusion, full thickness cartilage loss, and osteophytes are associated with having more knee pain. Although these features may be relevant targets for future trials, the clinical relevance of our findings is unclear because no feature was associated with a clinically important difference in knee pain.

Fat-suppressed T2 mapping of human knee femoral articular cartilage: comparison with conventional T2 mapping

Background

There is paucity of studies applying fat suppressed (FS) technique to T2 mapping to overcome chemical shift artifacts. The purpose of the study is to difference between FS T2 and conventional T2 mapping and reproducibility of FS T2 mapping in the femoral articular cartilage.

Methods

Eighteen patients who had normal-looking femoral cartilage and underwent knee MRI with conventional T2 and FS T2 mapping were included. T2 values of each mapping were measured by two readers independently from nine regions in the medial femoral condyle (MFC) and lateral femoral condyle (LFC). Each anatomical region was divided by lines at ± 10°, 30°, 50°, 70°, 90°, and 110°. Comparisons of T2 values between conventional and FS T2 mapping were statistically analyzed. The T2 values between FS and conventional T2 mapping in the anterior, central and posterior femoral condyles were compared.

Results

The overall femoral condyle T2 values from the FS T2 map were significantly lower than those from the conventional T2 map (48.5ms vs. 51.0ms, p < 0.001). The differences in the T2 values between the two maps were significantly different among the three divisions of the LFC (p = 0.009) and MFC (p = 0.031). The intra-class correlation coefficients indicated higher agreement in the FS T2 map than in the conventional T2 map (0.943 vs. 0.872).

Conclusions

The T2 values of knee femoral cartilage are significantly lower on FS T2 mapping than on conventional T2 mapping. FS T2 mapping is a more reproducible method for evaluating knee femoral cartilage.

Anterior cruciate ligament abnormalities are associated with accelerated progression of knee joint degeneration in knees with and without structural knee joint abnormalities: 96-month data from the Osteoarthritis Initiative

OBJECTIVE

To compare progression over 8 years in knee compositional cartilage degeneration and structural joint abnormalities in knees with different types of anterior cruciate ligament (ACL) abnormalities over 8 years.

METHOD

Baseline MR images of the right knees of 1899 individuals of the Osteoarthritis Initiative (OAI) with no evidence of or mild to moderate radiographic osteoarthritis were assessed for nontraumatic ACL abnormalities. The knees of 91 individuals showed nontraumatic ACL abnormalities (age 60.6 ± 9.8 y, 46 females; mucoid degeneration (MD), N = 37; complete tear (CT), N = 22; partial tear (PT), N = 32) and were frequency-matched to 91 individuals with normal ACL. MRIs were assessed for knee joint abnormalities using the Whole-Organ Magnetic Resonance Imaging Score (WORMS) and cartilage T2 mapping at baseline, 4- and 8-year follow-up.

RESULTS

Over 8 years, cartilage T2 values of the medial tibia showed a significantly greater increase in individuals with MD, PT or CT compared to those with normal ACL (adjusted rate of change/year [95% confidence interval], normal ACL: 0.06 [0.01, 0.23], MD: 0.34 [0.07, 0.73], PT, 0.21 [0.02, 0.33], CT, 0.51 [0.16, 0.78]), indicating an association of ACL abnormalities and an increased progression rate of cartilage degeneration in subjects with and without knee joint degeneration. This effect was also seen in cartilage T2 values averaged over all compartments (normal ACL: 0.08 [0.05, 0.20] vs abnormal ACL: 0.27 [0.06, 0.56]).

CONCLUSIONS

Over 8 years, higher progression rates of cartilage degeneration, especially in the medial tibia, were associated with ACL abnormalities compared to those with normal ACL, in subjects with and without knee joint abnormalities.

The association of meniscal body height with knee structural changes in middle-aged and elderly patients with symptomatic knee osteoarthritis

OBJECTIVES

To investigate whether and how meniscal height is associated with osteoarthritis (OA)-related knee structural changes in symptomatic knee OA.

METHODS

We studied 106 patients (61 female, aged 40-73 years) with symptomatic knee OA. X-ray was used for Kellgren-Lawrence score. Meniscal body heights and extrusion were measured on coronal sections of intermediate-weighted MRI sequence. Knee structural changes were assessed using the modified whole-organ magnetic resonance imaging score (WORMS). Associations between meniscal body height and knee structural changes were assessed using linear regression analysis.

RESULTS

Higher medial meniscal body height was significantly associated with severe medial meniscal lesions (p = 0.001-0.023), medial compartmental cartilage lesions (p = 0.045), patellofemoral compartmental and medial compartmental bone marrow edema patterns (p = 0.001-0.037), anterior cruciate ligament and patellar ligament abnormalities (p = 0.020-0.023), and loose bodies (p = 0.017). However, lateral meniscal body height was negatively correlated with WORMS scores for lateral meniscal lesions (p ≤ 0.018), lateral compartmental cartilage lesions (p ≤ 0.011), and lateral compartmental bone marrow edema patterns (p = 0.038).

CONCLUSION

Higher medial meniscal body height was associated with more severe medial compartment structural abnormalities and patellofemoral bone marrow edema patterns, while lateral meniscal body height was inversely correlated with the severity of lateral compartment structural abnormalities.

ADVANCES IN KNOWLEDGE

Our study revealed that meniscal body height was associated with multiple OA-related knee structural changes, which would be beneficial in identifying patients with or at risks for knee OA.

Quantitative 3D Ultrashort Echo Time Magnetization Transfer Imaging for Evaluation of Knee Cartilage Degeneration In Vivo

BACKGROUND

Recent studies suggest that macromolecular fraction (MMF) derived from three-dimensional ultrashort echo time magnetization transfer (UTE-MT) imaging is insensitive to the magic angle effect. However, its clinical use in osteoarthritis (OA) remains to be investigated.

PURPOSE

To investigate the feasibility of 3D UTE-MT-derived MMF in differentiating normal from degenerated cartilage.

STUDY TYPE

Prospective.

SUBJECTS

Sixty-two participants (54.8 ± 16.7 years, 30 females) with and without OA, plus two healthy volunteers (mean age 35.0 years) for reproducibility test.

FIELD STRENGTH/SEQUENCE

3 T/UTE-MT sequence.

ASSESSMENT

A 3D UTE-MT sequence was employed to calculate MMF based on a two-pool model. Kellgren-Lawrence (KL) grade and Whole-Organ Magnetic Resonance Imaging Score (WORMS) were evaluated by three experienced musculoskeletal radiologists. KL grade was condensed into three groups: KL0, KL1-2, and KL3-4. WORMS was regrouped based on extent of lesion (extent group) and depth of lesion (depth group), respectively. The performance of MMF at evaluating the degeneration of cartilage was assessed via Spearman's correlation coefficient and the area under the curve (AUC) calculated according to the receiver-operating characteristic curve.

STATISTICAL TESTS

After normality check, one-way analysis of variance was used to evaluate the performance. Tukey-Kramer test was performed for post hoc testing.

RESULTS

MMF showed significant negative correlations with KL grade (r = -0.53, P < 0.05) and WORMS (r = -0.49, P < 0.05). Significantly lower MMFs were found in subjects with greater KL grade (11.8 ± 0.8% for KL0; 10.9 ± 0.9% for KL1-2; 10.6 ± 1.1% for KL3-4; P < 0.05) and in cartilage with greater extent (12.1 ± 1.6% for normal cartilage; 10.9 ± 1.6% for regional lesions; 9.6 ± 1.7% for diffuse lesions; P < 0.05) and depth (12.1 ± 1.6% for normal cartilage; 10.6 ± 1.6% for partial-thickness lesions; 8.8 ± 1.7% for full-thickness lesions; P < 0.05) of lesions. AUC values of MMF for doubtful-minimal OA (KL1-2) and mild cartilage degradation (WORMS1-2) were 0.8 and 0.7, respectively.

DATA CONCLUSION

This study highlights the clinical potential of MMF in the detection of early OA.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 2.

Evaluation of articular cartilage with quantitative MRI in an equine model of post-traumatic osteoarthritis

Chondral lesions lead to degenerative changes in the surrounding cartilage tissue, increasing the risk of developing post-traumatic osteoarthritis (PTOA). This study aimed to investigate the feasibility of quantitative magnetic resonance imaging (qMRI) for evaluation of articular cartilage in PTOA. Articular explants containing surgically induced and repaired chondral lesions were obtained from the stifle joints of seven Shetland ponies (14 samples). Three age-matched nonoperated ponies served as controls (six samples). The samples were imaged at 9.4 T. The measured qMRI parameters included T₁ , T₂ , continuous-wave T_1ρ (CWT_1ρ ), adiabatic T_1ρ (AdT_1ρ ), and T_2ρ (AdT_2ρ ) and relaxation along a fictitious field (T_RAFF ). For reference, cartilage equilibrium and dynamic moduli, proteoglycan content and collagen fiber orientation were determined. Mean values and profiles from full-thickness cartilage regions of interest, at increasing distances from the lesions, were used to compare experimental against control and to correlate qMRI with the references. Significant alterations were detected by qMRI parameters, including prolonged T₁ , CWT_1ρ , and AdT_1ρ in the regions adjacent to the lesions. The changes were confirmed by the reference methods. CWT_1ρ was more strongly associated with the reference measurements and prolonged in the affected regions at lower spin-locking amplitudes. Moderate to strong correlations were found between all qMRI parameters and the reference parameters (ρ = -0.531 to -0.757). T₁ , low spin-lock amplitude CWT_1ρ , and AdT_1ρ were most responsive to changes in visually intact cartilage adjacent to the lesions. In the context of PTOA, these findings highlight the potential of T₁ , CWT_1ρ , and AdT_1ρ in evaluation of compositional and structural changes in cartilage.

Obese and overweight individuals have greater knee synovial inflammation and associated structural and cartilage compositional degeneration: data from the osteoarthritis initiative

OBJECTIVE

This work aims to study (i) the relationship between body mass index (BMI) and knee synovial inflammation using non-contrast-enhanced MRI and (ii) the association of synovial inflammation versus degenerative abnormalities and pain.

MATERIALS AND METHODS

Subjects with risk for and mild to moderate radiographic osteoarthritis were selected from the Osteoarthritis Initiative. Subjects were grouped into three BMI categories with 87 subjects per group: normal weight (BMI, 20-24.9 kg/m²), overweight (BMI, 25-29.9 kg/m²), and obese (BMI, ≥ 30 kg/m²), frequency matched for age, sex, race, Kellgren-Lawrence grade, and history of knee surgery and injury. Semi-quantitative synovial inflammation imaging biomarkers were obtained including effusion-synovitis, size and intensity of infrapatellar fat pad signal abnormality, and synovial proliferation score. Cartilage composition was measured using T₂ relaxation time and structural abnormalities using the whole-organ magnetic resonance imaging score (WORMS). The Western Ontario and McMasters (WOMAC) Osteoarthritis Index was used for pain assessment. Intra- and inter-reader reproducibility was assessed by kappa values.

RESULTS

Overweight and obese groups had higher prevalence and severity of all synovial inflammatory markers (p ≤ 0.03). Positive associations were found between synovial inflammation imaging biomarkers and average T₂ values, WORMS maximum scores and total WOMAC pain scores (p < 0.05). Intra- and inter-reader kappa values for imaging biomarkers were high (0.76-1.00 and 0.60-0.94, respectively).

CONCLUSION

Being overweight or obese was significantly associated with a greater prevalence and severity of synovial inflammation imaging biomarkers. Substantial reproducibility and high correlation with knee structural, cartilage compositional degeneration, and WOMAC pain scores validate the synovial inflammation biomarkers used in this study.

T2 analysis of the entire osteoarthritis initiative dataset

While substantial work has been done to understand the relationships between cartilage T₂ relaxation times and osteoarthritis (OA), diagnostic and prognostic abilities of T₂ on a large population yet need to be established. Using 3921 manually annotated 2D multi-slice multi-echo spin-echo magnetic resonance imaging volume, a segmentation model for automatic knee cartilage segmentation was built and evaluated. The optimized model was then used to calculate T₂ values on the entire osteoarthritis initiative (OAI) dataset composed of longitudinal acquisitions of 4796 unique patients, 25 729 magnetic resonance imaging studies in total. Cross-sectional relationships between T₂ values, OA risk factors, radiographic OA, and pain were analyzed in the entire OAI dataset. The performance of T₂ values in predicting the future incidence of radiographic OA as well as total knee replacement (TKR) were also explored. Automatic T₂ values were comparable with manual ones. Significant associations between T₂ relaxation times and demographic and clinical variables were found. Subjects in the highest 25% quartile of tibio-femoral T₂ values had a five times higher risk of radiographic OA incidence 2 years later. Elevation of medial femur T₂ values was significantly associated with TKR after 5 years (coeff = 0.10; P = .036; CI = [0.01,0.20]). Our investigation reinforces the predictive value of T₂ for future incidence OA and TKR. The inclusion of T₂ averages from the automatic segmentation model improved several evaluation metrics when compared to only using demographic and clinical variables.

Cartilage T2 Relaxation Times and Subchondral Trabecular Bone Parameters Predict Morphological Outcome After Matrix-Associated Autologous Chondrocyte Implantation With Autologous Bone Grafting

BACKGROUND

Quantitative magnetic resonance (MR) imaging techniques are established for evaluation of cartilage composition and trabecular bone microstructure at the knee. It remains unclear whether quantitative MR parameters predict the midterm morphological outcome after matrix-associated chondrocyte implantation (MACI) with autologous bone grafting (ABG).

PURPOSE

To assess longitudinal changes and associations of the biochemical composition of cartilage repair tissue, the subchondral bone architecture, and morphological knee joint abnormalities on 3-T MR imaging after MACI with ABG at the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Knees of 18 patients (28.7 ± 8.4 years [mean ± SD]; 5 women) were examined preoperatively and 3, 6, 12, and 24 months after MACI and ABG using 3-T MR imaging. Cartilage composition was assessed using T₂ relaxation time measurements. Subchondral bone microstructure was quantified using a 3-dimensional phase-cycled balanced steady-state free precision sequence. Trabecular bone parameters were calculated using a dual threshold algorithm (apparent bone fraction, apparent trabecular number, and apparent trabecular separation). Morphological abnormalities were assessed using the MOCART (magnetic resonace observation of cartilage repair tissue) score, the WORMS (Whole-Organ Magnetic Resonance Imaging Score), and the CROAKS (Cartilage Repair Osteoarthritis Knee Score). Clinical symptoms were assessed using the Tegner activity and Lysholm knee scores. Statistical analyses were performed by using multiple linear regression analysis.

RESULTS

Total WORMS (P = .02) and MOCART (P = .001) scores significantly improved over 24 months after MACI. Clinical symptoms were significantly associated with the presence of bone marrow edema pattern abnormalities 24 months after surgery (P = .035). Overall there was a good to excellent radiological outcome found after 24 months (MOCART score, 88.8 ± 10.1). Cartilage repair T₂ values significantly decreased between 12 and 24 months after MACI (P = .009). Lower global T₂ values after 3 months were significantly associated with better MOCART scores after 24 months (P = .04). Moreover, trabecular bone parameters after 3 months were significantly associated with the total WORMS after 24 months (apparent bone fraction, P = .048; apparent trabecular number, P = .013; apparent trabecular separation, P = .013).

CONCLUSION

After MACI with ABG, early postoperative quantitative assessment of biochemical composition of cartilage and microstructure of subchondral bone may predict the outcome after 24 months. The perioperative global joint cartilage matrix quality is essential for proper proliferation of the repair tissue, reflected by MOCART scores. The subchondral bone quality of the ABG site is essential for proper maturation of the cartilage repair tissue, reflected by cartilage T₂ values.

Association of blood pressure with knee cartilage composition and structural knee abnormalities: data from the osteoarthritis initiative

OBJECTIVE

To investigate the associations of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with changes in knee cartilage composition and joint structure over 48 months, using magnetic resonance imaging (MRI) data from the Osteoarthritis Initiative (OAI).

MATERIALS AND METHODS

A total of 1126 participants with right knee Kellgren-Lawrence (KL) score 0-2 at baseline, no history of rheumatoid arthritis, blood pressure measurements at baseline, and cartilage T2 measurements at baseline and 48 months were selected from the OAI. Cartilage composition was assessed using MRI T2 measurements, including laminar and gray-level co-occurrence matrix texture analyses. Structural knee abnormalities were graded using the whole-organ magnetic resonance imaging score (WORMS). We performed linear regression, adjusting for age, sex, body mass index, physical activity, smoking status, alcohol use, KL score, number of anti-hypertensive medications, and number of nonsteroidal anti-inflammatory drugs.

RESULTS

Higher baseline DBP was associated with greater increases in global T2 (coefficient 0.22 (95% CI 0.09, 0.34), P = 0.004), global superficial layer T2 (coefficient 0.39 (95% CI 0.20, 0.58), P = 0.001), global contrast (coefficient 15.67 (95% CI 8.81, 22.53), P < 0.001), global entropy (coefficient 0.02 (95% CI 0.01, 0.03) P = 0.011), and global variance (coefficient 9.14 (95% CI 5.18, 13.09), P < 0.001). Compared with DBP, the associations of SBP with change in cartilage T2 parameters and WORMS subscores showed estimates of smaller magnitude.

CONCLUSION

Higher baseline DBP was associated with higher and more heterogenous cartilage T2 values over 48 months, indicating increased cartilage matrix degenerative changes.

Does cartilage loss cause pain in osteoarthritis and if so, how much?

OBJECTIVES

Although treatment development in osteoarthritis (OA) focuses on chondroprotection, it is unclear how much preventing cartilage loss reduces joint pain. It is also unclear how nociceptive tissues may be involved.

METHODS

Using data from the Osteoarthritis Initiative, we quantified the relation between cartilage loss and worsening knee pain after adjusting for bone marrow lesions (BMLs) and synovitis, and examined how much these factors mediated this association. 600 knee MRIs were scored at baseline, 12 months and 24 months for quantitative and semiquantitative measures of OA structural features. We focused on change in medial cartilage thickness using an amount similar to that seen in recent trials. Linear models calculated mean change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score with cartilage loss, adjusted for baseline BMLs, synovitis and covariates. Mediation analysis tested whether change in synovitis or BMLs mediated the cartilage loss-pain association. We carried out a subanalysis for knees with non-zero baseline WOMAC pain scores and another for non-valgus knees.

RESULTS

Cartilage thickness loss was significantly associated with a small degree of worsening in pain over 24 months. For example, a loss of 0.1 mm of cartilage thickness over 2 years was associated with a 0.32 increase in WOMAC pain (scale 0-20). The association of cartilage thickness loss with pain was mediated by synovitis change but not by BML change. Subanalysis results were similar.

CONCLUSIONS

Cartilage thickness loss is associated with only a small amount of worsening knee pain, an association mediated in part by worsening synovitis. Demonstrating that chondroprotection reduces knee pain will be extremely challenging and is perhaps unachievable.

Clinical Utility of Advanced Imaging of the Knee

Advanced imaging modalities, including computed tomography, magnetic resonance imaging (MRI), and dynamic fluoroscopic imaging, allow for a comprehensive evaluation of the knee joint. Compositional sequences for MRI can allow for an evaluation of the biochemical properties of cartilage, meniscus, and ligament that offer further insight into pathology that may not be apparent on conventional clinical imaging. Advances in image processing, shape modeling, and dynamic studies also offer a novel way to evaluate common conditions and to monitor patients after treatment. The purpose of this article is to review advanced imaging modalities of the knee and their current and anticipated future applications to clinical practice. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:473-482, 2020.

Chondrocalcinosis is associated with increased knee joint degeneration over 4 years: data from the Osteoarthritis Initiative

OBJECTIVE

To determine if presence of calcium-containing crystals (CaC) is associated with increased knee joint degeneration over 4 years and assess if total number of CaCs deposited is a useful measure of disease burden.

DESIGN

Seventy subjects with CaCs in right knees at baseline were selected from the Osteoarthritis Initiative and matched to 70 subjects without evidence of CaCs. T1-weighted gradient-echo sequences were used to confirm presence of CaCs and count the numbers of distinct circumscribed CaCs. Morphological abnormalities were assessed at baseline and 4-year follow-up using the modified semi-quantitative Whole-Organ Magnetic Resonance Imaging Score (WORMS). Linear regression models were used to analyze the associations between presence of CaCs at baseline and changes in WORMS and to analyze the associations between numbers of circumscribed CaCs at baseline and changes in WORMS.

RESULTS

Presence of CaCs was associated with increased cartilage degeneration in the patella (coefficient: 0.33; 95% confidence interval (CI): 0.04-0.63), the medial femur (coefficient: 0.51; 95% CI: 0.18-0.83), the lateral tibia (coefficient: 0.36; 95% CI: 0.01-0.71) as well as the medial and lateral meniscus (coefficient: 0.38; 95% CI: 0.00-0.75 and coefficient: 0.72; 95% CI: 0.12-1.32). Knees with higher numbers of CaCs had increased cartilage degeneration in the patella and medial femur (coefficient: 0.09; 95% CI: 0.05-0.14; P < 0.001 and coefficient: 0.08; 95% CI: 0.02-0.14; P = 0.005).

CONCLUSIONS

CaCs were associated with increased cartilage and meniscus degeneration over a period of 4 years. Assessing the number of CaC depositions may be useful to evaluate risk of onset and worsening of degenerative disease.

Longitudinal MRI structural findings observed in accelerated knee osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVE

To analyze structural, longitudinal MRI findings during the development of accelerated knee osteoarthritis (AKOA) over 4 years.

MATERIALS AND METHODS

From the Osteoarthritis Initiative (OAI), knees with no radiographic osteoarthritis (KL 0/1) developing advanced-stage osteoarthritis (KL 3/4; AKOA) within a 4-year (y) timeframe were selected. MRIs were graded using the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) at the beginning of the 4-year timeframe (index visit), at 2-year, and 4-year follow-up. Morphological and clinical findings associated with KL 3/4 onset within 2 years compared to 4 years were assessed using generalized estimating equations.

RESULTS

AKOA was found in 162 knees of 149 subjects (age 63.25 ± 8.3; 103 females; BMI 29.4 ± 3.9). Moderate to severe meniscal lesions WORMS ≥ 3 were present in 25% (41/162) at the index visit, 64% (104/162) at 2-year and 93% (151/162) at 4-year follow-up. Meniscal extrusion was the most prevalent finding (ranging from 18% at the index visit, 45% at 2-year and 94% at 4-year follow-up) and root tears were the most common types of tears (9% at the index visit; 22% at 2 years and 38% at 4 years). Risk factors associated with KL 3/4 onset within 2 years included root tears at the index visit (adjusted OR, 2.82; 95% CI: 1.33, 6.00; p = 0.007) and incident knee injury (42%, 49/116 vs. 24%, 11/46, p = 0.032).

CONCLUSIONS

Meniscal abnormalities, in particular extrusion and root tears, were the most prevalent morphological features found in subjects with AKOA. These results suggest that meniscal abnormalities have a significant role in accelerated progression of OA.

Defective WNT signaling may protect from articular cartilage deterioration - a quantitative MRI study on subjects with a heterozygous WNT1 mutation

OBJECTIVE

WNT signaling is of key importance in chondrogenesis and defective WNT signaling may contribute to the pathogenesis of osteoarthritis and other cartilage diseases. Biochemical composition of articular cartilage in patients with aberrant WNT signaling has not been studied. Our objective was to assess the knee articular cartilage in WNT1 mutation-positive individuals using a 3.0T MRI unit to measure cartilage thickness, relaxation times, and texture features.

DESIGN

Cohort comprised mutation-positive (N = 13; age 17-76 years) and mutation-negative (N = 13; 16-77 years) subjects from two Finnish families with autosomal dominant WNT1 osteoporosis due to a heterozygous missense mutation c.652T>G (p.C218G) in WNT1. All subjects were imaged with a 3.0T MRI unit and assessed for cartilage thickness, T2 and T1ρ relaxation times, and T2 texture features contrast, dissimilarity and homogeneity of T2 relaxation time maps in six regions of interest (ROIs) in the tibiofemoral cartilage.

RESULTS

All three texture features showed opposing trends with age between the groups in the medial tibiofemoral cartilage (P = 0.020-0.085 for the difference of the regression coefficients), the mutation-positive individuals showing signs of cartilage preservation. No significant differences were observed in the lateral tibiofemoral cartilage. Cartilage thickness and means of T2 relaxation time did not differ between groups. Means of T1ρ relaxation time were significantly different in one ROI but the regression analysis displayed no differences.

CONCLUSIONS

Our results show less age-related cartilage deterioration in the WNT1 mutation-positive than the mutation-negative subjects. This suggests, that the WNT1 mutation may alter cartilage turnover and even have a potential cartilage-preserving effect.

[Biochemical cartilage imaging-update 2019]

BACKGROUND

Cartilage imaging using magnetic resonance imaging (MRI) is increasingly used for early detection of cartilage damage. Biochemical MR methods to assess cartilage damage are essential for optimal treatment planning.

PURPOSE

The aim of this review is to provide an update on advanced cartilage imaging based on biochemical MR techniques. The clinical applications and additional benefits compared to conventional MRI are presented.

MATERIALS AND METHODS

A literature search of PubMed regarding the clinical applications of various biochemical MR methods and morphological MR imaging was performed.

RESULTS

While T2 mapping can be easily implemented on clinical routine MR scanners, the T1rho method is technically more demanding and is not available on all MR scanners. dGEMRIC, which can be performed with all field strengths, is now severely restricted due to the recent decision of the European Medical Agency (EMA) to withdraw linear gadolinium contrast agents from the market because of proven gadolinium deposition in the brain. Sodium imaging is the most sensitive MRI method for glycosaminoglycan (GAG), but is limited to 7 T. In addition to early diagnosis of cartilage degeneration before morphological changes are visible, biochemical MRI offers predictive markers, e.g., effect of lifestyle changes or assessing results of cartilage repair surgery.

CONCLUSION

Cartilage imaging based on biochemical MRI allows a shift from qualitative to quantitative MRI. Biochemical MRI plays an increasingly important role in the early diagnosis of cartilage degeneration for monitoring of disease-modifying drugs and as predictive imaging biomarker in clinical diagnostics. In cartilage repair, monitoring of the efficacy of different cartilage repair surgery techniques to develop hyaline-like cartilage can be performed with biochemical MRI.

Weight loss regimen in obese and overweight individuals is associated with reduced cartilage degeneration: 96-month data from the Osteoarthritis Initiative

PURPOSE

To investigate change in knee cartilage composition over 96 months in overweight and obese participants with constant weight compared to those with weight loss (WL), and to assess how different WL regimens are associated with these changes.

METHODS

We studied right knees of 760 participants (age 62.6 ± 9.0y; 465 females) with a baseline body mass index (BMI) >25 kg/m2 from the Osteoarthritis Initiative with mild to moderate or with risk factors for knee osteoarthritis. Participants losing weight (>5% of baseline BMI over 72 months; N = 380) were compared to controls with stable weight (SW, N = 380). Participants losing weight were categorized based on WL method (diet and exercise, diet only, exercise only) and compared to those with stable weight. Magnetic resonance imaging (MRI) at 3T was performed at baseline, 48- and 96-months. The association of WL and WL method with change in cartilage composition, measured with T2 mapping, was analyzed using mixed random effects models.

RESULTS

Compared to SW, WL was associated with a significantly slower increase in global (averaged over all compartments) cartilage T2 (adjusted mean difference of change in T2 ms/year [95% CI] between the groups: 0.24 [0.20, 0.41] ms/year; P < 0.001) and global deep layer cartilage T2 0.35 [0.20, 0.42] ms/year; P < 0.001), suggesting slower cartilage deterioration. Compared to the SW group, slower increases in global T2 were observed in the diet and diet and exercise groups, but not in the exercise only group (P = 0.042, P = 0.003 and P = 0.85, respectively).

CONCLUSION

Our results suggest that WL may slow knee cartilage degeneration over 96 months, and that these potential benefits may differ by method of WL.

Is treated HIV infection associated with knee cartilage degeneration and structural changes? A longitudinal study using data from the osteoarthritis initiative

Background

Metabolic disorders presenting in HIV-infected patients on antiretroviral therapy (ART) may increase the risk of osteoarthritis. However, structural changes of the knee in HIV infected subjects are understudied. The aim of this study is to investigate knee cartilage degeneration and knee structural changes over 8 years in subjects with and without HIV infection determined based on the use of ART.

Methods

We studied 10 participants from the Osteoarthritis Initiative who received ART at baseline and 20 controls without ART, frequency matched for age, sex, race, baseline body mass index (BMI) and Kellgren & Lawrence grade. Knee abnormalities were assessed using the whole-organ magnetic resonance imaging score (WORMS) and cartilage T2 including laminar and texture analyses were analyzed using a multislice-multiecho spin-echo sequence. Signal abnormalities of the infrapatellar fat pad (IPFP) and suprapatellar fat pad (SPFP) were assessed separately using a semi-quantitative scoring system. Linear regression models were used in the cross-sectional analysis to compare the differences between ART/HIV subjects and controls in T2 (regular and laminar T2 values, texture parameters) and morphologic parameters (subscores of WORMS, scores for signal alterations of IPFP and SPFP). Mixed effects models were used in the longitudinal analysis to compare the rate of change in T2 and morphological parameters between groups over 8 years.

Results

At baseline, individuals on ART had significantly greater size of IPFP signal abnormalities (P = 0.008), higher signal intensities of SPFP (P = 0.015), higher effusion scores (P = 0.009), and lower subchondral cysts sum scores (P = 0.003) compared to the controls. No significant differences were found between the groups in T2-based cartilage parameters and WORMS scores for cartilage, meniscus, bone marrow edema patterns and ligaments (P > 0.05). Longitudinally, the HIV cohort had significantly higher global knee T2 entropy values (P = 0.047), more severe effusion (P = 0.001) but less severe subchondral cysts (P = 0.002) on average over 8 years.

Conclusions

Knees of individuals with HIV on ART had a more heterogeneous cartilage matrix, more severe synovitis and abnormalities of the IPFP and SPFP, which may increase the risk of incident knee osteoarthritis.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2573-5) contains supplementary material, which is available to authorized users.

Bone marrow lesion is associated with disability for activities of daily living in patients with early stage knee osteoarthritis

Osteoarthritis of the knee (knee OA) induces pain, loss of mobility and diminished activities of daily living (ADL). Although an understanding of the pathophysiology of early stage knee OA has been developed, the structural changes associated with disability for ADL in early stage knee OA are still unclear. The aim of the present study was to examine magnetic resonance imaging (MRI)-detected changes associated with disability for ADL in patients with early stage knee OA. One hundred and thirty-two patients with early stage medial knee OA (Kellgren-Lawrence grade ≤ 2) who first visited the outpatient clinic at our university hospital were included. They were also examined by 3.0-Tesla knee MRI. The OA-associated structural changes were scored using the Whole-Organ Magnetic Resonance Imaging Score (WORMS), and clinical manifestations were evaluated by the Japanese Knee Osteoarthritis Measure (JKOM). Median quartile regression was used for the analysis. Cartilage lesion, subchondral bone attrition and osteophytes were observed in all patients. Bone marrow lesions (BMLs) and synovitis were observed in 60% and 55% of the patients, respectively. Subchondral cysts and ligament changes were observed in 6% and 17% of the patients, respectively. Pain severity of the patients was associated with medial cartilage lesions (coefficient 2.50, 95% confidence interval 0.61-4.40, p < 0.01). Disability for ADL of the patients was associated with BMLs in the medial side of the knee joint (0.82, 0.21-1.02, p = 0.04). BMLs in the medial side of the knee joint were associated with disability for ADL of patients with early stage medial knee OA.

MRI T2 and T1ρ relaxation in patients at risk for knee osteoarthritis: a systematic review and meta-analysis

Background

Magnetic resonance imaging (MRI) T2 and T1ρ relaxation are increasingly being proposed as imaging biomarkers potentially capable of detecting biochemical changes in articular cartilage before structural changes are evident. We aimed to: 1) summarize MRI methods of published studies investigating T2 and T1ρ relaxation time in participants at risk for but without radiographic knee OA; and 2) compare T2 and T1ρ relaxation between participants at-risk for knee OA and healthy controls.

Methods

We conducted a systematic review of studies reporting T2 and T1ρ relaxation data that included both participants at risk for knee OA and healthy controls. Participant characteristics, MRI methodology, and T1ρ and T2 relaxation data were extracted. Standardized mean differences (SMDs) were calculated within each study. Pooled effect sizes were then calculated for six commonly segmented knee compartments.

Results

55 articles met eligibility criteria. There was considerable variability between scanners, coils, software, scanning protocols, pulse sequences, and post-processing. Moderate risk of bias due to lack of blinding was common. Pooled effect sizes indicated participants at risk for knee OA had lengthened T2 relaxation time in all compartments (SMDs from 0.33 to 0.74; p < 0.01) and lengthened T1ρ relaxation time in the femoral compartments (SMD from 0.35 to 0.40; p < 0.001).

Conclusions

T2 and T1ρ relaxation distinguish participants at risk for knee OA from healthy controls. Greater standardization of MRI methods is both warranted and required for progress towards biomarker validation.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2547-7) contains supplementary material, which is available to authorized users.

T2-relaxation time of cartilage repair tissue is associated with bone remodeling after spongiosa-augmented matrix-associated autologous chondrocyte implantation

OBJECTIVE

To investigate whether T2 relaxation time measurements of cartilage repair tissue and structural changes of the knee joint are associated with subchondral bone architecture after spongiosa-augmented matrix-associated autologous chondrocyte implantation (MACI).

DESIGN

Both knees of 25 patients (25.5 ± 7.8y; 10 women) were examined preoperatively and 2.7 years after unilateral spongiosa-augmented MACI with 3T magnetic resonance (MR) imaging. Cartilage composition was assessed using T2 relaxation time measurements, subchondral trabecular bone microstructure was quantified using a 3D phase-cycled balanced steady state free-precision sequence. Structural knee joint changes were assessed using the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was used for the postoperative description of the area that underwent MACI. Correlations were assessed using Spearman's rank correlation coefficients.

RESULTS

Hypertrophy of the cartilage repair tissue was found in 2 of 25 patients, both after a MACI procedure at the patella, 21 patients showed congruent filling. In subchondral bone of the cartilage repair compartment, apparent trabecular thickness was significantly higher in compartments with elevated cartilage T2 (n = 17; 0.37 ± 0.05 mm) compared to those showing no difference in cartilage T2 compared to the same compartment in the contralateral knee (n = 8; 0.27 ± 0.05 mm; P = 0.042). Significant correlations were found between the overall progression of WORMS and the ipsilateral vs contralateral ratio of average trabecular thickness (r = 0.48, P = 0.031) and bone fraction (r = 0.57, P = 0.007).

CONCLUSIONS

After spongiosa-augmented MACI, T2 values of cartilage repair tissue and structural knee joint changes correlated with the quality of the underlying trabecular bone.

Prediction of Lumbar Disk Herniation and Clinical Outcome Using Quantitative Magnetic Resonance Imaging: A 5-Year Follow-Up Study

OBJECTIVES

The aim of this study was to assess the predictive value of T2 mapping at baseline with regard to the development of disk herniation and clinical outcome at a 5-year follow-up in patients with low back pain.

MATERIALS AND METHODS

Twenty-five symptomatic patients (13 male; mean age, 44.0 years; range, 24-64 years at baseline) were examined at 3 T magnetic resonance imaging, with a 5-year follow-up. Region of interest analysis was performed on 125 lumbar intervertebral disks on 2 central sagittal T2 maps. Absolute T2 relaxation times and a T2 value ratio of the posterior annulus fibrosus as a percentage of the nucleus pulposus (NPAF) were evaluated for each disk. All disks were graded morphologically using the Pfirrmann score. Roland-Morris Disability Questionnaires (RMDQ) and a visual analogue scale (VAS) were assessed for each patient at follow-up as a clinical end point and compared with diagnosed lumbar disk herniation. Statistical analysis was conducted by a biomedical statistician.

RESULTS

Using the baseline NPAF ratio, follow-up development of herniation was predicted with an area under the curve (AUC) of 0.893 in a receiver operating characteristic curve. The same was done using the baseline nucleus pulposus T2, resulting in an AUC of 0.901. Baseline and follow-up NPAF, as well as baseline and follow-up nucleus pulposus T2, differed significantly (P < 0.001) between disks with no herniation, disks with herniation at baseline, and disks with new herniation at follow-up. Difference was still significant (all P < 0.001), when only testing for difference in degenerated discs with Pfirrmann score III to V. Calculating sensitivity and specificity for herniation prediction only in discs with Pfirmann III to V using a receiver operating characteristic, AUC was 0.844 with baseline herniations excluded.The lowest baseline nucleus pulposus T2 per patient correlated significantly with follow-up RMDQ (r = -0.517; P = 0.008) and VAS (r = -0.494; P = 0.012). The highest baseline NPAF correlated significantly with RMDQ (r = 0.462; P = 0.020), but not VAS (r = 0.279; P = 0.177).

CONCLUSIONS

Quantitative T2 mapping may serve as a clinically feasible, noninvasive imaging biomarker that can indicate disks at risk for herniation and correlates with clinical outcome and subjective patient burden in a representative cohort of patients with low back pain.

Systematic review and meta-analysis of the reliability and discriminative validity of cartilage compositional MRI in knee osteoarthritis

OBJECTIVE

To assess reliability and discriminative validity of cartilage compositional magnetic resonance imaging (MRI) in knee osteoarthritis (OA).

DESIGN

The study was carried out per PRISMA recommendations. We searched MEDLINE and EMBASE (1974 - present) for eligible studies. We performed qualitative synthesis of reliability data. Where data from at least two discrimination studies were available, we estimated pooled standardized mean difference (SMD) between subjects with and without OA. Discrimination analyses compared controls and subjects with mild OA (Kellgren-Lawrence (KL) grade 1-2), severe OA (KL grade 3-4) and OA not otherwise specified (NOS) where not possible to stratify. We assessed quality of the evidence using Quality Appraisal of Diagnostic Reliability (QAREL) and Quality Assessment of Diagnostic Accuracy (QUADAS-2) tools.

RESULTS

Fifty-eight studies were included in the reliability analysis and 26 studies were included in the discrimination analysis, with data from a total of 2,007 knees. Intra-observer, inter-observer and test-retest reliability of compositional techniques were excellent with most intraclass correlation coefficients >0.8 and coefficients of variation <10%. T1rho and T2 relaxometry were significant discriminators between subjects with mild OA and controls, and between subjects with OA (NOS) and controls (P < 0.001). T1rho showed best discrimination for mild OA (SMD [95% CI] = 0.73 [0.40 to 1.06], P < 0.001) and OA (NOS) (0.60 [0.41 to 0.80], P < 0.001). Quality of evidence was moderate for both parts of the review.

CONCLUSIONS

Cartilage compositional MRI techniques are reliable and, in the case of T1rho and T2 relaxometry, can discriminate between subjects with OA and controls.

Type 2 diabetes patients have accelerated cartilage matrix degeneration compared to diabetes free controls: data from the Osteoarthritis Initiative

PURPOSE

Osteoarthritis (OA) and diabetes mellitus (DM) share common risk factors with a potential underlying relationship between both diseases. The purpose of this study was to investigate the longitudinal effects of DM on cartilage deterioration over 24-months with MR-based T2 relaxation time measurements.

METHODS

From the Osteoarthritis Initiative (OAI) cohort 196 diabetics were matched in small sets for age, sex, BMI and Kellgren-Lawrence score with 196 non-diabetic controls. Knee cartilage semi-automatic segmentation was performed on 2D multi-slice multi-echo spin-echo sequences. Texture of cartilage T2 maps was obtained via grey level co-occurrence matrix analysis. Linear regression analysis was used to compare cross-sectional and changes in T2 and texture parameters between the groups.

RESULTS

Both study groups were similar in age (63.3 vs 63.0 years, P = 0.70), BMI (30.9 vs 31.2 kg/m2, P = 0.52), sex (female 53.6% vs 54.1%, P = 0.92) and KL score distribution (P = 0.97). In diabetics, except for the patella, all compartments showed a significantly higher increase in mean T2 values when compared to non-diabetic controls. Global T2 values increased almost twice as much; 1.77ms vs 0.98ms (0.79ms [CI: 0.39,1.19]) (P < 0.001). Additionally, global T2 values showed a significantly higher increase in the bone layer (P = 0.006), and in a separate analysis of the texture parameters, diabetics also showed consistently higher texture values (P < 0.05), indicating a more disordered cartilage composition.

CONCLUSION

Cartilage T2 values in diabetics show a faster increase with a consistently more heterogeneous cartilage texture composition. DM seems to be a risk factor for developing early OA with an accelerated degeneration of the articular cartilage in the knee.

Hyperintense signal alteration in the suprapatellar fat pad on MRI is associated with degeneration of the patellofemoral joint over 48 months: data from the Osteoarthritis Initiative

OBJECTIVE

To analyze associations of suprapatellar fat pad (SPFP) hyperintense signal alterations and mass effect with progression of patellofemoral osteoarthritis (OA) and clinical symptoms over 48 months.

MATERIALS AND METHODS

Subjects from the Osteoarthritis Initiative (n = 426; 51.8 ± 3.8 years; 49.8% women) without radiographic tibiofemoral OA underwent 3T-MRI of their right knees and clinical evaluation using the Knee Injury and Osteoarthritis Outcome Score at baseline and at 48 months. Elevated SPFP signal was assessed on intermediate-weighted, fat-saturated turbo spin-echo (TSE) images. Mass effect was defined as a convex posterior contour. Patellofemoral cartilage, bone marrow lesions (BML), and subchondral cysts were assessed using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Associations of SPFP imaging findings with MRI and clinical progression were assessed using general linear models and logistic regressions.

RESULTS

Baseline SPFP signal alterations were found in 51% of the subjects (n = 217), of whom 11% (n = 23) additionally had a mass effect. Progression of cartilage lesions was significantly higher in subjects with signal alteration versus without (adjusted mean increases, 95% CI; patella: 0.29, -0.07 to 0.64 vs -0.04, -0.40 to 0.31; p < 0.001; trochlea: 0.47, 0.16 to 0.77 vs 0.31, 0.01 to 0.61; p = 0.007). BML progression was also more likely in subjects with signal alteration (OR 1.75, 95% CI 1.09 to 2.82; p = 0.021). Mass effect was not associated with joint degeneration and SPFP findings were not associated with clinical worsening (p > 0.18 for all).

CONCLUSION

Patellofemoral joint degeneration over 48 months was significantly increased in subjects with SPFP signal alteration, suggesting an association between SPFP abnormalities and the progression of patellofemoral OA.

Imaging Bone-Cartilage Interactions in Osteoarthritis Using [18F]-NaF PET-MRI

Purpose:

Simultaneous positron emission tomography–magnetic resonance imaging (PET-MRI) is an emerging technology providing both anatomical and functional images without increasing the scan time. Compared to the traditional PET/computed tomography imaging, it also exposes the patient to significantly less radiation and provides better anatomical images as MRI provides superior soft tissue characterization. Using PET-MRI, we aim to study interactions between cartilage composition and bone function simultaneously, in knee osteoarthritis (OA).

Procedures:

In this article, bone turnover and remodeling was studied using [¹⁸F]-sodium fluoride (NaF) PET data. Quantitative MR-derived T_1ρ relaxation times characterized the biochemical cartilage degeneration. Sixteen participants with early signs of OA of the knee received intravenous injections of [¹⁸F]-NaF at the onset of PET-MR image acquisition. Regions of interest were identified, and kinetic analysis of dynamic PET data provided the rate of uptake (K_i) and the normalized uptake (standardized uptake value) of [¹⁸F]-NaF in the bone. Morphological MR images and quantitative voxel-based T_1ρ maps of cartilage were obtained using an atlas-based registration technique to segment cartilage automatically. Voxel-by-voxel statistical parameter mapping was used to investigate the relationship between bone and cartilage.

Results:

Increases in cartilage T_1ρ, indicating degenerative changes, were associated with increased turnover in the adjoining bone but reduced turnover in the nonadjoining compartments. Associations between pain and increased bone uptake were seen in the absence of morphological lesions in cartilage, but the relationship was reversed in the presence of incident cartilage lesions.

Conclusion:

This study shows significant cartilage and bone interactions in OA of the knee joint using simultaneous [¹⁸F]-NaF PET-MR, the first in human study. These observations highlight the complex biomechanical and biochemical interactions in the whole knee joint in OA, which potentially could help assess therapeutic targets in treating OA.

Effect of intra-articular injection of intermediate-weight hyaluronic acid on hip and knee cartilage: in-vivo evaluation using T2 mapping

OBJECTIVES

We used T2 mapping to quantify the effect of intra-articular hyaluronic acid administration (IAHAA) on cartilage with correlation to clinical symptoms.

METHODS

One hundred two patients with clinical and MRI diagnosis of hip or knee grade I-III chondropathy were prospectively included. All patients received a standard MRI examination of the affected hip/knee (one joint/patient) and T2-mapping multiecho sequence for cartilage evaluation. T2 values of all slices were averaged and used for analysis. One month after MR evaluation 72 patients (38 males; mean age 51±10 years) underwent IAHAA. As a control group, 30 subjects (15 males; 51 ± 9 years) were not treated. MR and WOMAC evaluation was performed at baseline and after 3, 9, and 15 months in all patients.

RESULTS

T2 mapping in hyaluronic acid (HA) patients showed a significant increase in T2 relaxation times from baseline to the first time point after therapy in knees (40.7 ± 9.8 ms vs. 45.8 ± 8.6 ms) and hips (40.9 ± 9.7 ms; 45.9 ± 9.5 ms) (p < 0.001). At the 9- and 15-month evaluations, T2 relaxation dropped to values similar to the baseline ones (p < 0.001 vs. 3 month). The correlation between T2 increase and pain reduction after IAHAA was statistically significant (r = 0.54, p < 0.01) in patients with grade III chondropathy.

CONCLUSIONS

T2 mapping can be used to evaluate the effect over time of IAHAA in patients with hip and knee chondropathy.

KEY POINTS

• T2 relaxation times change over time after hyaluronic acid intra-articular administration • T2 relaxation times of the medial femoral condyle correlate with WOMAC variation • T2 relaxation times are different between Outerbridge I and II-III.

Conservatively treated knee injury is associated with knee cartilage matrix degeneration measured with MRI-based T2 relaxation times: data from the osteoarthritis initiative

OBJECTIVE

To investigate the association of cartilage degeneration with previous knee injuries not undergoing surgery, determined by morphologic and quantitative 3-T magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We performed a nested cross-sectional study of right knee MRIs from participants in the Osteoarthritis Initiative (OAI) aged 45-79 with baseline Kellgren-Lawrence score of 0-2. Cases were 142 right knees of patients with self-reported history of injury limiting the ability to walk for at least 2 days. Controls were 426 right knees without history of injury, frequency-matched to cases on age, BMI, gender, KL scores and race (1:3 ratio). Cases and controls were compared using covariate-adjusted linear regression analysis, with the outcomes of region-specific T2 mean, laminar analysis and heterogeneity measured by texture analysis to investigate early cartilage matrix abnormalities and the Whole-Organ Magnetic Resonance Imaging Score (WORMS) to investigate morphologic knee lesions.

RESULTS

Compared to control subjects, we found significantly higher mean T2 values in the injury [lateral tibia (28.10 ms vs. 29.11 ms, p = 0.001), medial tibia (29.70 ms vs. 30.40 ms, p = 0.014) and global knee cartilage (32.73 ms vs. 33.29 ms, p = 0.005)]. Injury subjects also had more heterogeneous cartilage as measured by GLCM texture contrast, variance and entropy (p < 0.05 in 14 out of 18 texture parameters). WORMS gradings were not significantly different between the two groups (p > 0.05).

CONCLUSION

A history of knee injury not treated surgically is associated with higher and more heterogeneous T2 values, but not with morphologic knee abnormalities. Our findings suggest that significant, conservatively treated knee injuries are associated with permanent cartilage matrix abnormalities.

Association of weight change with progression of meniscal intrasubstance degeneration over 48 months: Data from the Osteoarthritis Initiative

OBJECTIVES

To investigate the association of weight change over 48 months with progression of meniscal intrasubstance degeneration (MID).

METHODS

We studied 487 subjects with MID at baseline and after 48 months using 3-T MRI with the same protocol (FSE sequences with and without fat suppression). These participants lost weight (≥3%, n = 141), had moderate weight gain (3-10%, n = 77), substantial weight gain (>10%, n = 15) or maintained stable weight (n = 254). Progression of MID to a meniscal tear was assessed using the WORMS grading system and compared among weight change groups using logistic regression. ANOVA and chi-square tests were used to study the differences in subjects' characteristics.

RESULTS

Progression of MID increased from weight loss to substantial weight gain (p < 0.001) and was significantly more likely with both moderate weight gain (odds ratio [OR], 4.9; 95% confidence interval [CI] 2.4-8.9) and substantial weight gain (OR, 9.5; 95% CI 3.2-28.5) compared to stable weight. Results were similar in both menisci for moderate weight gain (medial: OR, 6.8; 95% CI 3.5-11.3; lateral: OR, 2.6; 95% CI 1.1-6.6) and substantial weight gain (medial: OR, 21.0; 95% CI 5.1-80.7; lateral: OR, 9.7; 95% CI 0.95-100.2).

CONCLUSION

Weight gain is associated with an increased likelihood that meniscal intrasubstance degeneration will progress with the risk increasing with greater weight gain.

KEY POINTS

• Subjects who gained weight were more likely to develop meniscal tears. • Greater amount of weight gain was associated with an increasing likelihood of progression. • Prevention of weight gain has health benefits for the meniscus.

Subregional laminar cartilage MR spin-spin relaxation times (T2) in osteoarthritic knees with and without medial femorotibial cartilage loss - data from the Osteoarthritis Initiative (OAI)

OBJECTIVE

To explore whether subregional laminar femorotibial cartilage spin-spin relaxation time (T2) is associated with subsequent radiographic progression and cartilage loss and/or whether one-year change in subregional laminar femorotibial cartilage T2 is associated with concurrent progression in knees with established radiographic OA (ROA).

METHODS

In this case-control study, Osteoarthritis Initiative (OAI) knees with medial femorotibial progression were selected based on one-year loss in both quantitative cartilage thickness Magnetic resonance imaging (MRI) and radiographic joint space width (JSW). Non-progressor knees were matched by sex, Body mass index (BMI), baseline Kellgren-Lawrence-grade (2/3), and pain. Baseline and one-year follow-up superficial and deep cartilage T2 was analyzed in 16 femorotibial subregions using multi-echo spin-echo MRI.

RESULTS

37 knees showed medial femorotibial progression whereas 37 matched controls had no medial or lateral compartment progression. No statistically significant baseline differences between progressor and non-progressor knees in medial femorotibial cartilage T2 were observed in the superficial (48.9 ± 3.0 ms; 95% CI: [47.9, 49.9] vs 47.8 ± 3.6 ms; 95% CI: [46.6, 49.0], P = 0.07) or deep cartilage layer (40.8 ± 3.6 ms; 95% CI: [39.5, 42.0] vs 40.1 ± 4.7 ms; 95% CI: [38.5, 41.6], P = 0.29). Concurrent T2 change was more pronounced in the deep than the superficial cartilage layer. In the medial femorotibial compartment (MFTC), longitudinal change was greater in the deep layer of progressor than non-progressor knees (1.8 ± 4.5 ms; 95% CI: [0.3, 3.3] vs -0.2 ± 1.9 ms; 95% CI: [-0.8, 0.5], P = 0.02), whereas no difference was observed in the superficial layer.

CONCLUSION

Medial compartment cartilage T2 did not appear to be a strong prognostic factor for subsequent structural progression in the same compartment of knees with established ROA, when appropriately controlling for covariates. Yet, deep layer T2 change in the medial compartment occurred concurrent with medial femorotibial progression.

Association of diabetes mellitus and biochemical knee cartilage composition assessed by T2 relaxation time measurements: Data from the osteoarthritis initiative

PURPOSE

To investigate the association of the presence and severity of diabetes mellitus (DM) with articular cartilage composition, using magnetic resonance imaging (MRI)-based T₂ relaxation time measurements, and structural knee abnormalities.

MATERIALS AND METHODS

In the Osteoarthritis Initiative 208, participants with DM (age 63.0 ± 8.9 years; 111 females) and risk factors for osteoarthritis (OA) or mild radiographic tibiofemoral OA (Kellgren-Lawrence [KL] grade ≤2) were identified and group-matched with 208 controls without DM (age 63.3 ± 9.1 years; 111 females). Subjects with diabetes-related renal or ophthalmological complications or insulin treatment at baseline (n = 50) were defined as severe DM. 3T MR images of the right knee were assessed for articular cartilage T₂ , including texture and laminar analyses derived from the patella, medial, and lateral femur and tibia and for structural abnormalities using the modified whole-organ magnetic resonance imaging score (WORMS). Clustered linear regression analyses were used to assess associations of DM with MRI findings.

RESULTS

DM subjects had significantly higher cartilage T₂ in the patella (mean difference 0.92 msec [95% confidence interval (CI) 0.79, 1.06]; P = 0.001) and medial femur (mean difference 0.36 msec [95% CI 0.27, 0.81]; P = 0.006) compared to controls. Averaged over all compartments, DM subjects showed significantly higher texture parameters (variance, P = 0.001; contrast, P = 0.002; entropy, P < 0.001). Subjects with severe DM additionally showed higher T₂ in the medial tibial deep and superficial layers (P = 0.011 and P = 0.041) compared to controls. No significant differences in cartilage, meniscus, and overall WORMS were found between the groups (P > 0.05).

CONCLUSION

In comparison to nondiabetic controls, cartilage in DM subjects showed higher and more heterogeneous cartilage T₂ values, indicating increased articular cartilage degeneration. This affected even more compartments in subjects with severe DM.

LEVEL OF EVIDENCE

2 Technical Efficacy: 5 J. Magn. Reson. Imaging 2018;47:380-390.