Abnormalities of articular cartilage in the knee: analysis of available MR techniques

Grading of Cartilage Damage in Degenerative Knee Osteoarthritis Based on Quantitative Parameters of the Infrapatellar Fat Pad: A Cross-Sectional Study

PURPOSE

The aim of this research was to investigate the relationship between quantitative texture parameters and degenerative cartilage damage in knee osteoarthritis (KOA) by conducting a full-volume texture analysis of infrapatellar fat pad (IFP). In addition, this study also explored if the quantitative texture parameter models outperform semi-quantitative model in cartilage damage classification tasks.

MATERIALS AND METHODS

This retrospective study involved 202 patients who were diagnosed with KOA using imaging and clinical examinations. Texture parameters of the IFP were extracted from sagittal FSE PDWI fat-suppressed sequence images, and least absolute shrinkage and selection operator regression was used for feature selection. Spearman correlation analysis was conducted to assess the relationship between semi-quantitative parameter (Hoffa-synovitis score), quantitative parameters, and cartilage damage. Five multi-classification logistic regression models were developed to predict cartilage damage grade by using Hoffa-synovitis score, texture parameters, and clinical characteristics as independent variables. Subsequently, the performance of these models was compared.

RESULTS

Eight texture features were screened out in this study. Correlation analysis showed that Hoffa synovitis score, texture parameters, and cartilage damage grade were significantly correlated (all P < 0.05). The strongest correlation was found between Hoffa-synovitis score and cartilage damage, demonstrating a moderate positive relationship (r = 0.62). In terms of texture features, the Correlation parameter exhibited a moderate positive correlation with cartilage damage (r = 0.49), while other texture parameters had a slight positive correlation degree of positive or negative correlation. In the task of classifying cartilage damage, the model's macro-average area under the curve (AUC) only using the Hoffa-synovitis score was 0.73 (95% confidence interval (CI): 0.64, 0.83), while the model using only selected texture parameters achieved a macro-average AUC of 0.84 (95% CI: 0.68, 0.94). Furthermore, the model that combined texture parameters and clinical features also achieved a macro-average AUC of 0.84 (95% CI: 0.72, 0.94). By integrating the Hoffa-synovitis score, texture parameters, and clinical features, the model's macro-average AUC experienced a slight improvement to 0.85 (95% CI: 0.74, 0.93). Notably, the model combining only Hoffa-synovitis score and texture parameters had the best classification performance, with a macro-average AUC of 0.88 (95% CI: 77, 0.97). The performance of the 4 models incorporating texture parameters outperformed that of the Hoffa-synovitis score alone (all P < 0.05), however with no significant statistical difference observed among the 4 models (all P > 0.05).

CONCLUSIONS

There existed a correlation between the texture parameters of the infrapatellar fat IFP and cartilage damage in KOA. The models using texture parameters demonstrated better performance in classifying cartilage damage compared to the models using only semi-quantitative parameter. Thus, we can infer that texture parameters had the potential to be valuable imaging biomarkers for evaluating cartilage damage.

The patellar compression angle: a new, accurate diagnostic angle for lateral patellar compression syndrome

BACKGROUND

Lateral patellar compression syndrome (LPCS) is a common cause of anterior knee pain. Early diagnosis of LPCS using an accurate radiological examination is, therefore, important. However, the currently used radiological examinations for detecting LPCS are poor diagnostic indicators. Therefore, the aim of this study was to establish a new diagnostic imaging examination for LPCS and evaluate its accuracy in comparison with conventional examinations.

METHODS

From June 2020 to May 2023, a retrospective analysis was conducted on 72 patients in the LPCS group and 140 patients in the Control group, all of whom underwent axial radiographs of the patella and knee MRI. The patellar compression angle (PCA), Tilting angle (TA), Congruence angle (CA), Grelsamer angle (AG), and Lateral patellofemoral angle (LPA) were used and compared statistically for their accuracy in terms of diagnosing LPCS.

RESULTS

The area under the receiver operating characteristic curve (ROC) for the PCA was 0.87, which was the highest among the five examinations. ROC analysis revealed that a smaller PCA, less than 14.7°, was associated with LPCS, with the highest sensitivity (80.6%), specificity (82.9%), accuracy (82.1%), positive predictive value (PPV, 70.7%), negative predictive value (NPV, 89.2%), positive likelihood ratio (PLR, 4.71), and lowest negative likelihood ratio (NLR, 0.23) compared with the other four examinations. The interobserver reproducibility of the PCA was good, with an intraclass correlation coefficients (ICCs) of 0.85.

CONCLUSIONS

The PCA can detect LPCS with a moderate diagnostic performance and could, therefore, might be a new angle for the diagnosis of LPCS in clinical settings.

What can be observed in intervertebral cartilage endplate with aging? An animal model study of excessive axial mechanical loading

Introduction

The cartilage endplate (CEP) plays a crucial role as both a mechanical barrier and nutrient channel for the intervertebral disc, but it is vulnerable to excessive axial loading. We modified the Ilizarov external fixator and applied it to the CEP of the rat tail to impose diurnal, controllable excess axial loading. The objective was to measure morphological changes in the CEP when subjected to loading during the aging process.

Methods

Two Kirschner wires were, respectively, inserted into the center of the eighth and ninth coccygeal vertebrae (Co8/9) of rat (n = 54) to apply axial loading to the CEP. A remote control device was used to establish the diurnal loading schedule. At the end of 4, 8, and 12-week periods, the Co8/9 CEPs in each group were analyzed using MRI, histological staining, and immunohistochemical staining techniques.

Results

The novel Ilizarov model that we modified successfully induced degeneration of the rat coccygeal CEP. MRI analysis revealed significant degenerative changes in the loaded Co8/9 CEP, including decreased signal intensity and the formation of Schmorl's nodes at 8 and 12 weeks. Histological examination showed progressive CEP degeneration (CEPD), characterized by decreased microporosity, thinning, and structural irregularities. Immunohistochemical analysis demonstrated a significant reduction in Aggrecan and Collagen II expression in the CEP and nucleus pulposus over time. Control and sham groups maintained normal CEP structure and composition throughout the study period.

Conclusion

Excessive axial loading induced CEPD in the rat tail, primarily characterized by the formation of Schmorl's nodes and a reduction in CEP microporosity in this study. Our modified Ilizarov rat tail compression model, featuring stable and controllable axial loading capabilities, provided an alternative experimental paradigm for further investigation into CEPD.

Quantitative Magnetic Resonance Imaging Had Greater Sensitivity in Diagnosing Chondral Lesions of the Knee: A Systematic Review and Meta-analysis

PURPOSE

To investigate the accuracy and reliability of magnetic resonance imaging (MRI) in identifying and grading chondral lesions and explore the optimal imaging technique to image cartilage.

METHOD

A comprehensive search was conducted on Medline, Embase, and Cochrane Library. Eligible cohort studies published before August 2022 were included. The study reports used MRI to diagnose and grade cartilage lesions, with intraoperative findings as the reference standard. Summary estimates of diagnostic performance were obtained. The reliability of MRI interpretation was summarized. Subgroup analyses were performed based on assessed imaging techniques, field strength, and joint surface.

RESULTS

Forty-three trials and 3,706 patients were included in the systematic review. The overall area under curve for hierarchical summarized receiver operating characteristics was 0.91 (95% confidence interval [CI] 0.88-0.93). The pooled sensitivity for quantitative MRI, 3-dimensional MRI, and 2-dimensional MRI was 0.82 (95% CI 0.64-0.92), 0.79 (95% CI 0.74-0.83), and 0.63 (95% CI 0.51-0.73), respectively. The pooled sensitivity of 3 Tesla (3T), 1.5 Tesla (1.5T), and <1.5 Tesla MRI was 0.79 (95% CI 0.72-0.85), 0.67 (95% CI 0.60-0.74), and 0.55 (95% CI 0.39-0.71), respectively. There were differences in interobserver consistency across different studies.

CONCLUSIONS

In general, MRI had high specificity in discriminating normal cartilage, but its sensitivity for identifying chondral lesions is less optimal. Further analysis showed that quantitative MRI, 3D MRI, and 3T MRI demonstrate greater sensitivity compared with 2D MRI, 1.5T MRI, and <1.5 Tesla MRI.

LEVEL OF EVIDENCE

Level III, systematic review of Level II and III studies.

3D-DESS MRI with CAIPIRINHA two- and fourfold acceleration for quantitatively assessing knee cartilage morphology

OBJECTIVES

This study aimed to assess the diagnostic image quality and compare the knee cartilage segmentation results using a controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA)-accelerated 3D-dual echo steady-state (DESS) research package sequence in the knee.

MATERIALS AND METHODS

A total of 64 subjects underwent both two- and fourfold CAIPIRINHA-accelerated 3D-DESS and DESS without parallel acceleration technique of the knee on a 3.0 T system. Two musculoskeletal radiologists evaluated the images independently for image quality and diagnostic capability following randomization and anonymization. The consistency of automatic segmentation results between sequences was explored using an automatic knee cartilage segmentation research application. The descriptive statistics and inter-observer and inter-method concordance of various acceleration sequences were investigated. P values < .05 were considered significant.

RESULTS

For image quality evaluation, the image signal-to-noise ratio and contrast-to-noise ratio decreased with the decrease in scanning time. However, it is accompanied by the reduction of artifacts. Using 3D-DESS without parallel acceleration technique as the standard for cartilage grading diagnosisand the diagnostic agreement of two- and fourfold CAIPIRINHA-accelerated 3D-DESS was good, kappa value was 0.860 (P < .001) and 0.804 (p < 0.001), respectively. Regarding cartilage defects, the sensitivity and specificity of the twofold acceleration 3D-CAIPIRINHA-DESS were 95.56% and 97.70%, and the fourfold CAIPIRINHA-accelerated 3D-DESS were 91.49% and 97.65%, respectively. The intraclass correlation coefficients of various sequences in cartilage segmentation were almost all greater than 0.9.

CONCLUSION

The CAIPIRINHA-accelerated 3D-DESS sequence maintained comparable diagnostic and segmentations performance of knee cartilage after a 60% scan time reduction.

Automated measurement and grading of knee cartilage thickness: a deep learning-based approach

Background

Knee cartilage is the most crucial structure in the knee, and the reduction of cartilage thickness is a significant factor in the occurrence and development of osteoarthritis. Measuring cartilage thickness allows for a more accurate assessment of cartilage wear, but this process is relatively time-consuming. Our objectives encompass using various DL methods to segment knee cartilage from MRIs taken with different equipment and parameters, building a DL-based model for measuring and grading knee cartilage, and establishing a standardized database of knee cartilage thickness.

Methods

In this retrospective study, we selected a mixed knee MRI dataset consisting of 700 cases from four datasets with varying cartilage thickness. We employed four convolutional neural networks-UNet, UNet++, ResUNet, and TransUNet-to train and segment the mixed dataset, leveraging an extensive array of labeled data for effective supervised learning. Subsequently, we measured and graded the thickness of knee cartilage in 12 regions. Finally, a standard knee cartilage thickness dataset was established using 291 cases with ages ranging from 20 to 45 years and a Kellgren-Lawrence grading of 0.

Results

The validation results of network segmentation showed that TransUNet performed the best in the mixed dataset, with an overall dice similarity coefficient of 0.813 and an Intersection over Union of 0.692. The model's mean absolute percentage error for automatic measurement and grading after segmentation was 0.831. The experiment also yielded standard knee cartilage thickness, with an average thickness of 1.98 mm for the femoral cartilage and 2.14 mm for the tibial cartilage.

Conclusion

By selecting the best knee cartilage segmentation network, we built a model with a stronger generalization ability to automatically segment, measure, and grade cartilage thickness. This model can assist surgeons in more accurately and efficiently diagnosing changes in patients' cartilage thickness.

Comprehensive Study on Scoring and Grading Systems for Predicting the Severity of Knee Osteoarthritis

Knee Osteoarthritis (KOA) is a degenerative joint ailment characterized by cartilage loss, which can be seen using imaging modalities and converted into imaging features. The older population is the most affected by knee OA, which affects 16% of people worldwide who are 15 years of age and older. Due to cartilage tissue degradation, primary knee OA develops in older people. In contrast, joint overuse or trauma in younger people can cause secondary knee OA. Early identification of knee OA, according to research, may be a successful management tactic for the condition. Scoring scales and grading systems are important tools for the management of knee osteoarthritis as they allow clinicians to measure the progression of the disease's severity and provide suggestions on suitable treatment at identified stages. The comprehensive study reviews various subjective and objective knee evaluation scoring systems that effectively score and grade the KOA based on where defects or changes in articular cartilage occur. Recent studies reveal that AI-based approaches, such as that of DenseNet, integrating the concept of deep learning for scoring and grading the KOA, outperform various state-of-the-art methods in order to predict the KOA at an early stage.

Guidelines for the diagnosis and treatment of knee osteoarthritis with integrative medicine based on traditional Chinese medicine

Knee osteoarthritis (KOA) is a common geriatric disease in middle-aged and elderly people. Its main pathological characteristics are articular cartilage degeneration, changes in subchondral bone reactivity, osteophyte formation at joint edges, synovial disease, ligament relaxation or contracture, and joint capsular contracture. The prevalence rate of symptomatic KOA in middle-aged and elderly people in China is 8.1%, and this is increasing. The main clinical manifestations of this disease are pain and limited activity of the knee joint, which seriously affect the quality of life of patients and may cause disability, posing a huge burden on society and the economy. Although the pathogenesis of KOA is not clear, the treatment of KOA is diverse, and Chinese medicine, which mainly relies on plant-based natural products, has a relatively stable and reliable curative effect. This guideline aims to emphasize the evidence-based staging and stepped treatment of KOA and the therapeutic effect of integrative medicine based on traditional Chinese medicine on KOA. We make recommendations that include the adoption of manual therapy, acupuncture, external application of herbs, herbal plasters, exercise therapy, and other integrative medicine based on traditional Chinese medicine. Users of the above guidelines are most likely to include clinicians and health managers in healthcare settings.

Assessing lateral femoral condyle cartilage prior to medial UKA: MRI vs. Valgus stress radiograph

BACKGROUND

The cartilage quality of the lateral compartment needs to be clarified prior to medial unicompartmental knee arthroplasty (UKA). Valgus stress radiograph has been recommended as the preferred tool. Some studies also show that magnetic resonance imaging (MRI) has a higher diagnostic value. So, we conducted this study to compare whether valgus stress radiographic lateral joint space width (LJSW) and MRI grading can accurately reflect cartilage quality and its screening value for UKA-suitable patients.

METHODS

One hundred and thirty eight knees proposed for UKA were enrolled prospectively. Valgus stress radiograph was taken to measure LJSW. LJSW > 4 mm was considered normal and suitable for UKA. For weight-bearing area cartilage of lateral femoral condyle, Recht grade was assessed by MRI preoperatively. Recht grades ≤ 2 were treated as non-high-grade injuries while Recht grades > 2 were treated as high-grade injuries. Outerbridge grade was the gold standard and was assessed intraoperatively. Patients with Outerbridge grades 0-2 (non-high-grade injuries) underwent UKA, and patients with Outerbridge grades 3-4 (high-grade injuries) underwent total knee arthroplasty (TKA). The diagnostic parameters of valgus stress radiograph and MRI for the selection of UKA candidates were calculated, and receiver operating characteristic curves were drawn. P < 0.05 was considered significant.

RESULTS

Of 138 knees, 120 underwent UKAs, and 18 underwent TKAs. In terms of selecting UKA candidates, the sensitivity was close between MRI (95.0%) and valgus stress radiograph (96.7%), and the specificity, accuracy, positive predictive value and negative predictive value of MRI (94.4%, 94.9%, 99.1%, 73.9%, respectively) were higher than that of valgus stress radiograph (5.9%, 85.5%, 88.0%, 20.0%, respectively). The difference in area under the curve (AUC) between MRI (0.950) and LJSW (0.602) was significant (P = 0.001).

CONCLUSION

Compared with valgus stress radiograph, MRI has excellent evaluation value in diagnosing lateral weight-bearing cartilage injuries and can be used as a reliable tool for selecting suitable UKA patients.

A randomized, parallel control and multicenter clinical trial of evidence-based traditional Chinese medicine massage treatment VS External Diclofenac Diethylamine Emulgel for the treatment of knee osteoarthritis

BACKGROUND

Both massage and topically administered NSAIDs are safe and effective treatments for knee osteoarthritis (KOA); however, different massage technique sects in China caused assessment difficulties for the treatment of KOA. In order to standardize the massage techniques and procedures, we organized multi-disciplinary experts in China to acquire an evidence-based traditional Chinese medicine massage treatment of knee osteoarthritis. The purposes of this study will be to provide clinicians a complementary and alternative therapy for patients and to evaluate the efficacy and safety of evidence-based traditional Chinese medicine massage treatment of KOA compared to External Diclofenac Diethylamine Emulgel.

METHODS AND DESIGN

A randomized controlled trial in which 300 participants diagnosed with KOA will be recruited and randomly allocated to either the experimental group or the control group in a ratio of 2:1. Two hundred participants will receive evidence-based traditional Chinese medicine massage 2 sessions per week for 10 weeks as the experimental group, and 100 participants will receive External Diclofenac Diethylamine Emulgel 3-4 times per day for 10 weeks as the control group. The patients in the two groups will receive follow-up at two time points at 5 weeks and 10 weeks from the beginning of treatment, respectively. The MRI scans and X-ray will be performed at baseline and at the end of the intervention. The primary outcome will be the changes in the Western Ontario and McMaster Osteoarthritis Index (WOMAC). Secondary outcomes will be measured by the PRO scale for knee osteoarthritis based on the concept of traditional Chinese medicine (Chinese scale for knee osteoarthritis (CSKO)), X-ray evaluation, and MRI scan evaluation. The data of WOMAC and CSKO will be analyzed at the baseline, 5 weeks, and 10 weeks from the beginning of treatment. The data from MRI scans and X-rays will be analyzed at baseline and at the end of the intervention. The significance level sets as 5%. The safety of interventions will be evaluated after each treatment session.

DISCUSSION

This study will provide clinicians with much-needed knowledge for the treatment of KOA through a controlled trial.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1800014400 . Registered on 10 January 2018.

Relationship between Classification of Fabellae and the Severity of Knee Osteoarthritis: A Relevant Study in the Chinese Population

Objective

To classify the fabellae and discuss the relationship between the classification of fabellae and the severity of knee osteoarthritis (KOA) in Chinese.

Methods

From February 2019 to February 2020, 136 patients were measured and classified using three‐dimensional computed tomography (CT) reconstruction. According to the CT imaging characteristics, the fabellae were divided into five types: type I, a fabella on the lateral femoral condyle; type II, a fabella on the medial femoral condyle; type III, a fabella on the lateral femoral condyle and a fabella on the medial femoral condyle; type IV, two fabellae on the medial femoral condyle; and type V, two fabellae on the lateral femoral condyle. The severity of KOA was assessed on the Recht grade by magnetic resonance imaging (MRI). The data were analyzed with SPSS 24.0.

Results

The classification of fabellae were correlated with KOA grades (χ² = 35.026, P < 0.05). In terms of KOA grades, grade I and grade II were occupied most by fabellar type II (32, 72.8%); type II and other types showed significant statistical difference (P < 0.05). Grade I and grade II were also mainly fabellar type IV (four, 100%). Fabellar type V's biggest component was grade III and grade IV (six, 75%). Type IV and type V showed significant statistical difference (P < 0.05).

Conclusion

The classification of fabellae were correlated with KOA grades. The type II may mean the lower KOA grades while type V may mean the higher KOA grades.

West Lake staging: A new staging system orchestrated by X-ray and MRI on knee osteoarthritis

Purpose: To investigate the differences on X-ray and MRI among each stage of knee osteoarthritis (KOA) and further propose a new staging system called West Lake (WL) staging. Methods: A cross-sectional study was conducted on patients with KOA. Stage I, II, III, and IV were divided based on stepwise treatment strategy of Knee osteoarthritis (KOA). Joint space widths (JSW) were measured on X-rays, whereas cartilage injuries (CI) and bone marrow lesions (BML) were evaluated on MRI. The differences of them across the groups were calculated by T-test. Receiver operating characteristic (ROC) curves were rendered to obtain the areas under the curves (AUC), Youden index and corresponding cut-off points. Results: Eventually, there were significant differences on JSW, CI, and BML between stage II/III and III/IV, while no significant differences between stage I/II. In stage II/III, the AUC of JSW, CI, BML was 0.99, 0.76, 0.71 and the Youden index was 0.94, 0.38, 0.45, meanwhile the cut-off points were ≤5.1 mm, >1, >2. In stage III/IV, the AUC of JSW, CI, BML was 0.96, 0.79, 0.74 and the Youden index was 0.84, 0.58, 0.38, meanwhile the cut-off points were ≤3.2 mm, >3, >4. Conclusion: The WL staging was described as follows: Stage I, X-ray shows no joint space narrow, normal MRI or MRI shows cartilage degeneration and only 1 or 2 sections are involved in BML. Stage II, X-ray shows joint space narrow, MRI shows cartilage defect but no full-thickness cartilage defect, meanwhile 3 or 4 sections are involved in BML. Stage III, X-ray shows serious joint space narrow even JSW disappeared, MRI shows full-thickness cartilage defect, more than 4 sections are involved in BML.

3D MRI of Articular Cartilage

Osteoarthritis, characterized by the breakdown of articular cartilage and other joint structures, is one of the most prevalent and disabling chronic diseases in the United States. Magnetic resonance imaging is a commonly used imaging modality to evaluate patients with joint pain. Both two-dimensional fast spin-echo sequences (2D-FSE) and three-dimensional (3D) sequences are used in clinical practice to evaluate articular cartilage. The 3D sequences have many advantages compared with 2D-FSE sequences, such as their high in-plane spatial resolution, thin continuous slices that reduce the effects of partial volume averaging, and ability to create multiplanar reformat images following a single acquisition. This article reviews the different 3D imaging techniques available for evaluating cartilage morphology, illustrates the strengths and weaknesses of 3D approaches compared with 2D-FSE approaches for cartilage imaging, and summarizes the diagnostic performance of 2D-FSE and 3D sequences for detecting cartilage lesions within the knee and hip joints.

Knee Cartilage Imaging

Articular cartilage injury and degeneration represent common causes of knee pain, which can be evaluated accurately and noninvasively using MRI. This review describes the structure of cartilage focusing on its histologic appearance to emphasize that structure will dictate patterns of tissue failure as well as MR appearance. In addition to identifying cartilage loss, MRI can demonstrate signal changes that correspond to intrinsic structural abnormalities which place the cartilage at risk for subsequent more serious injury or premature degeneration, allowing for earlier intervention and treatment of important causes of pain and morbidity.

Relationship Between Magnetic Resonance T2-Mapping and Matrix Metalloproteinase 1,3 in Knee Osteoarthritis

OBJECTIVE

To investigate the relationship between quantitative analysis of MRI (T2-mapping) and the expression of matrix metalloproteinase (MMP-1, MMP-3) in osteoarthritis of the knee joint and the role of MMP-1,3 in the pathogenesis of osteoarthritis.

METHODS

Thirty cases of knee osteoarthritis (KOA) patients with total knee arthroplasty (TKA) (lesion group) and 30 healthy adult volunteers (control group) were scanned with 1.5 T routine MR and T2-mapping, and their T2 values were measured and statistically analyzed. The pathological examination of the knee cartilage that was replaced during the operation and the immunohistochemical assay were used to measure the expression of MMP-1,3. The correlation between the T2 value of magnetic resonance imaging and the expression of MMP-1,3 was analyzed.

RESULTS

(1) According to the Recht grading standard for magnetic resonance, the T2 value of magnetic resonance increased significantly with the increase of cartilage degeneration. The differences in T2 values between each level and the normal group were statistically significant (P  < 0.05). (2) The T2 value of magnetic resonance imaging increased with the severity of the cartilage degeneration pathological Mankin grading, and the difference was statistically significant (P  <  0.05). (3) The expression of MMP-1,3 increased with cartilage degeneration. (4) The T2 value and the expression of MMP-1 in cartilage showed a linear trend. The result of Spearman correlation analysis showed that the expression of MMP-1,3 increased as the cartilage T2 value increased. There was a positive linear correlation between the two.

CONCLUSION

The T2 value of magnetic resonance increased with the degeneration of KOA cartilage. The expression of MMP-1,3 increased with the severity of articular cartilage destruction. The T2 value of KOA magnetic resonance was positively correlated with the expression of MMP-1,3.

Associations between suprapatellar pouch effusion-synovitis, serum cartilage oligomeric matrix protein, high sensitivity C-reaction protein, knee symptom, and joint structural changes in patients with knee osteoarthritis

OBJECTIVES

To investigate the cross-sectional associations between suprapatellar pouch effusion-synovitis and serum levels of cartilage oligomeric matrix protein (COMP), high sensitivity C-reaction protein (hs-CRP), knee symptom, and structural changes in patients with symptomatic knee osteoarthritis (OA).

METHOD

A total of 173 subjects were included. The osteophytes, joint space narrowing (JSN), and radiographic severity of OA were determined using X-ray. Cartilage defects, bone marrow lesions (BMLs), and suprapatellar pouch effusion-synovitis were assessed using magnetic resonance imaging. Serum levels of COMP and hs-CRP were measured by enzyme-linked immunosorbent assay. The knee joint symptom was self-reported using visual analogue scale.

RESULTS

In this OA cohort, after adjustment for age, sex, and BMI, the presence of pathological effusion-synovitis was associated with serum levels of COMP (β: 30.98, P = 0.018), and suprapatellar pouch effusion-synovitis maximum areas were associated with serum hs-CRP levels. Both suprapatellar pouch effusion-synovitis maximum area and grade were associated with osteophytes and Kellgren-Lawrence scores (ORs: 1.29-1.54, all P < 0.05). In patients with high tertile of hs-CRP, both suprapatellar pouch effusion-synovitis maximum area and grade were associated with cartilage defects at lateral and medial tibiofemoral sites (ORs: 3.01-8.41, all P < 0.05) after adjustment for covariates. In female patients, the significant associations were present between suprapatellar pouch effusion-synovitis and medial tibiofemoral BMLs (ORs: 1.43-1.53, all P < 0.05) after adjustment for covariates.

CONCLUSIONS

Suprapatellar pouch effusion-synovitis was associated with serum levels of COMP as well as hs-CRP and knee structural abnormalities in patients with knee OA. These suggested that effusion-synovitis may play a role in knee OA.Key Points• Suprapatellar pouch effusion-synovitis is associated with serum levels of COMP in patients with knee OA.• Suprapatellar pouch effusion-synovitis is associated with cartilage defects in knee OA patients with high systemic inflammation.

A comparison of the use of a suprapatellar Chinese Aircraft-shaped Sleeve System versus suprapatellar intramedullary nailing for tibial shaft fractures: Outcomes over a one-year follow-up

INTRODUCTION

This study aimed to investigate the effectiveness and safety of the Chinese Aircraft-shaped Sleeve (CASS) system on the clinical outcomes of tibial intermedullary nailing using a suprapatellar approach for the treatment of tibial fractures in a cohort of adult Chinese patients over a minimum one-year follow-up.

METHODS

After institutional review board approval, skeletally mature patients with Orthopaedic Trauma Association (OTA) type 42 tibial shaft fractures were randomized into either a SP approach using CASS group or a conventional SP approach group after informed consent was obtained. The operations were performed by a single senior orthopaedic surgeon according to group assignments. A group of 33 patients were treated using the CASS system and the other group of 34 patients were treated using a conventional SP approach. Both groups fully complied with research requirements and completed 12 months of follow-up. Magnetic resonance images (MRI) were obtained for the evaluation of the patellofemoral joint (PFJ) and residual debris preoperatively, as well as one week and 12 months postoperatively. Radiographs were used to assess alignment and union, visual analog scores (VAS) were used to assess anterior knee pain, and range of motion (ROM) and the Lysholm knee scoring scales were used for evaluating the operated knee at the 12-month follow-up.

RESULTS

Differences in cartilage lesion changes observed by MRI between the two groups were statistically significant (P = 0.030 at 1 week postoperatively; P = 0.025 at 12 months postoperatively). No significant differences were evident with respect to debris residue, malalignments, nonunion, VAS, ROM and Lysholm knee scoring scale with the exception of stair climbing (P = 0.02).

CONCLUSION

Based on the data of this one-year clinical follow-up study, the SP approach using the CASS system offers the potential to benefit patients suffering from tibial shaft fractures, who will be treated with intramedullary nailing especially for smaller patients.

Evaluation of Cartilage in the Wrist using Magnetic Resonance Imaging

Wrist pain is a common patient complaint with a myriad of clinical conditions that can explain the underlying cause. Short of wrist arthroscopy, no technique other than formal wrist arthrotomy exists for direct examination of the hyaline cartilage coating the articular surfaces of the carpal bones. Magnetic resonance imaging (MRI) has been proven accurate in evaluating joint surfaces of large joints such as the shoulder, hip, and knee with articular cartilage surface thickness is in excess of 1 mm. However, in the carpus the thickness of the cartilage and the contours present have precluded accurate imaging. Advances in MRI technology over the last several decades are now making imaging of small joint surfaces, such as the carpus, an area worth revisiting. Herein we provide a review of these efforts with a specific focus on the evaluation of the wrist.

[Mid-term effectiveness of arthroscopic anterior cruciate ligament reconstruction combined with meniscus allograft transplantation]

Objective

To summarize the mid-term effectiveness of arthroscopic anterior cruciate ligament (ACL) reconstruction combined with meniscus allograft transplantation.

Methods

A clinical data of 21 patients treated with arthroscopic ACL reconstruction and meniscus allograft transplantation and followed up more than 5 years between February 2007 and December 2014 was retrospectively analyzed. There were 12 males and 9 females, aged from 18 to 45 years, with an average age of 23.5 years. The cause of injury was sport sprain in 15 cases, falling in 4 cases, and traffic accident in 2 cases. The time from injury to operation ranged from 2 to 36 months, with an average of 12 months. Among them, 15 patients underwent previous meniscectomy, with an average interval of 1.6 years (range, 3 months to 6.5 years). All patients were primary ACL reconstruction. Preoperative anterior drawer test, Lachman test, and pivot shift test were positive. Lysholm score was 43.6±10.2. International Knee Documentation Committee (IKDC) score was 60.50±14.06. Of the 21 patients, 10 were gradeⅠ-Ⅱcartilage injuries and 11 were grade Ⅲ cartilage injuries according to MRI.

Results

All patients were followed up 5.1-7.8 years, with an average of 5.5 years. There were 2 cases of numbness of lower extremity, 3 cases of slight exudation of incision, 2 cases of articular movement bounce, 5 cases of mild joint swelling and pain after exercise. At last follow-up, Lachman tests were negative in 18 cases and positive in 3 cases; anterior drawer tests were negative in 19 cases and positive in 2 cases; pivot shift tests were negative in all cases. Lysholm score was 84.5±16.5 and IKDC score was 85.25±4.60, which were significantly higher than those before operation ( P<0.01). The flexion and extension of the affected knee joint were (128±13) and (3±7)°, respectively, which were smaller than those of the healthy knee joint [(133±15), (0±5)°] ( P<0.01). The results of KT-1000 test showed that when knee flexion was 30 and 90°, tibial anterior displacement of affected side [(2.35±1.20), (1.60±1.15) mm] were not significantly different from those of healthy side [(1.20±1.10), (1.10±1.03) mm] ( P>0.01). MRI showed that the ACL graft was in normal position and meniscus survived well. Cartilage injuries were gradeⅠ-Ⅱ in 18 cases and grade Ⅲ in 3 cases.

Conclusion

For patients with severe meniscus injury and ACL rupture, ACL reconstruction combined with meniscus allograft transplantation can restore the stability of the joint, recover the meniscus function which is conducive to the protection of articular cartilage and obtain satisfactory mid-term effectiveness.

Efficacy of magnetic resonance imaging with an SPGR sequence for the early evaluation of knee cartilage degeneration and the relationship between cartilage and other tissues

Rationale and objectives

The aim of this study was to investigate the efficacy of magnetic resonance imaging (MRI) with a spoiled gradient-recalled (SPGR) sequence to evaluate early knee cartilage degeneration and the relationship between cartilage and other tissues using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS).

Materials and methods

Eighty-four patients with knee joint pain were evaluated by X-ray and MRI with an SPGR sequence from June 2015 to December 2016. Joint degeneration was graded by two experienced radiologists using the Kellgren-Lawrence (K-L) grading scale. The modified WORMS was used to evaluate cartilage lesions, bone marrow abnormalities, bone cysts, osteophytes, joint effusion and synovitis. The difference between the WORMS of the SPGR and the T2 sequences evaluated by the Wilcoxon signed-rank test was determined, and the relationships between the WORMS features were evaluated by a Spearman correlation.

Results

The modified WORMS for the cartilage lesion evaluation was significantly higher with the SPGR sequence than with the T2 sequence (P < 0.05). The cartilage lesions showed a moderate correlation with osteophytes, synovitis and joint effusion (Rs > 0.40, P < 0.05) and weak correlations with bone marrow abnormalities and bone cysts (Rs < 0.4, P < 0.05).

Conclusion

The modified WORMS evaluation using MRI with the SPGR sequence was much better than the normal sequence for early knee osteoarthritis (OA). The cartilage lesions are associated with bone marrow abnormalities and the other features of OA.

Mechanoadaptation: articular cartilage through thick and thin

The articular cartilage is exquisitely sensitive to mechanical load. Its structure is largely defined by the mechanical environment and destruction in osteoarthritis is the pathophysiological consequence of abnormal mechanics. It is often overlooked that disuse of joints causes profound loss of volume in the articular cartilage, a clinical observation first described in polio patients and stroke victims. Through the 1980s, the results of studies exploiting experimental joint immobilisation supported this. Importantly, this substantial body of work was also the first to describe metabolic changes that resulted in decreased synthesis of matrix molecules, especially sulfated proteoglycans. The molecular mechanisms that underlie disuse atrophy are poorly understood despite the identification of multiple mechanosensing mechanisms in cartilage. Moreover, there has been a tendency to equate cartilage loss with osteoarthritic degeneration. Here, we review the historic literature and clarify the structural, metabolic and clinical features that clearly distinguish cartilage loss due to disuse atrophy and those due to osteoarthritis. We speculate on the molecular sensing pathways in cartilage that may be responsible for cartilage mechanoadaptation.

Cartilage oligomeric protein, matrix metalloproteinase-3, and Coll2-1 as serum biomarkers in knee osteoarthritis: a cross-sectional study

Biochemical markers reflecting joint remodeling in osteoarthritis (OA) are a promising diagnostic tool. The aim of this study was to investigate serum levels of candidate biomarkers in subjects with and without knee OA and assess their correlation with clinical parameters and knee structural damage. 56 patients with primary knee OA and 31 healthy controls participated in this study. Patients were separated into two groups: isolated knee OA and generalized OA. Clinical parameters were obtained by validated self-reported questionnaires and a visual analogue scale. Serum levels of cartilage oligomeric protein (COMP), matrix metalloproteinase-3 (MMP-3), and Coll2-1 were quantified by enzyme-linked immunosorbent assay. Knee structural damage was determined by plain X-ray and 1.5 T magnetic resonance imaging (MRI), using Kellgren-Lawrence (KL) grading scale and Whole-Organ Magnetic Resonance Imaging Score (WORMS), respectively. Compared to controls, patients had significantly higher median serum COMP (985 vs. 625 ng/ml; p < 0.001) and MMP-3 (36.85 vs. 22.10 ng/ml; p = 0.003) levels. Patients with radiographic evidence of KLII/III knee OA had greater median COMP levels than KLI patients (1095 vs. 720 ng/ml; p = 0.001). In the generalized OA group, mean MMP-3 levels were higher than in the isolated knee OA group (30.40 vs. 55.13 ng/ml; p < 0.001). COMP correlated positively with WORMS (r s = 0.454, p < 0.001) and MMP-3 (r s = 0.337, p = 0.003). Cut-off values for serum COMP and MMP-3 were determined. We observed higher serum COMP and MMP-3 levels in knee OA patients compared to controls. COMP may reflect knee structural damage, while MMP-3-OA "generalization".

A novel approach for intra-operative shape acquisition of the tibio-femoral joints using 3D laser scanning in computer assisted orthopaedic surgery

BACKGROUND

Image registration (IR) is an important process of developing a spatial relationship between pre-operative data and the physical patient in the operation theatre. Current IR techniques for Computer Assisted Orthopaedic Surgery (CAOS) are time consuming and costly. There is a need to automate and accelerate this process.

METHODS

Bespoke quick, cost effective, contactless and automated 3D laser scanning techniques based on the DAVID Laserscanner method were designed. 10 cadaveric knee joints were intra-operatively laser scanned and were registered with the pre-operative MRI scans. The results are supported with a concurrent validity study.

RESULTS

The average absolute errors between scan models were systematically less than 1 mm. Errors on femoral surfaces were higher than tibial surfaces (P<0.05). Additionally, scans acquired through the large exposure produced higher errors than the smaller exposure (P<0.05).

CONCLUSION

This study has provided proof of concept for a novel automated shape acquisition and registration technique for CAOS.

Effects of Surgical Factors on Cartilage Can Be Detected Using Quantitative Magnetic Resonance Imaging After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Quantitative magnetic resonance (qMR) can be used to measure macromolecules in tissues and is a potential method of observing early cartilage changes in the development of posttraumatic osteoarthritis. Hypothesis/Purpose: We hypothesized that specific patient and surgical factors affecting cartilage matrix composition after anterior cruciate ligament (ACL) reconstruction (ACLR) can be detected using T1ρ and T2 relaxation times. Our purpose was to demonstrate this ability in a multicenter feasibility study.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 54 patients who underwent ACLR underwent bilateral MRI at baseline before surgery and 6 months postoperatively. Operative findings were recorded. T1ρ and T2 relaxation times were calculated for 6 cartilage regions: the medial femur, lateral femur, medial tibia, lateral tibia, patella, and trochlea. A paired t test compared relaxation times at baseline and 6 months, univariate regression identified regions that influenced patient-reported outcome measures, and analysis of covariance was used to determine the surgical factors that resulted in elevated relaxation times at 6 months.

RESULTS

The injured knee had significantly prolonged T1ρ and T2 relaxation times in the tibiofemoral compartment at baseline and 6 months but had shorter values in the patellofemoral compartment compared with the uninjured knee. Prolonged T1ρ and T2 times at 6 months were noted for both the injured and uninjured knees. At 6 months, prolongation of T1ρ and T2 times in the tibial region was associated with lower patient-reported outcome measures. ACLR performed within 30 days of injury had significantly shorter T1ρ times in the tibial regions, and lateral meniscal tears treated with repair had significantly shorter T1ρ times than those treated with excision.

CONCLUSION

Prolonged relaxation times in multiple regions demonstrate how the injury affects the entire joint after an ACL tear. Changes observed in the uninjured knee may be caused by increased loading during rehabilitation, especially in the patellofemoral articular cartilage and distal femur. Relaxation times in the tibial regions may be predictive of patient symptoms at 6 months. These same regions are affected by surgical timing as early as 30 days after injury, but this may partially be reflective of the severity of the preoperative injury and the choice of treatment of meniscal tears.

Association between MRI-detected knee joint regional effusion-synovitis and structural changes in older adults: a cohort study

OBJECTIVE

To describe the cross-sectional and longitudinal associations between knee regional effusion-synovitis and structural changes in older adults.

METHODS

A total of 977 subjects were randomly selected from the local community (mean 62 years, 50% female) at baseline and 404 were followed up 2.6 years later. T2-weighted MRI was used to assess knee effusion-synovitis in four subregions: suprapatellar pouch, central portion, posterior femoral recess and subpopliteal recess. Knee cartilage defects, cartilage volume and bone marrow lesions (BMLs) were measured using MRI at baseline and follow-up.

RESULTS

Cross-sectionally, effusion-synovitis in most subregions was significantly associated with a higher risk of cartilage defects, BMLs and reduced cartilage volume. Longitudinally, suprapatellar pouch effusion-synovitis at baseline predicted an increase in cartilage defects (p<0.01), loss of cartilage volume (p=0.04) and an increase in BMLs (p=0.02) in multivariable analyses. The significant associations of effusion-synovitis with cartilage volume and BMLs disappeared after adjustment for cartilage defects. Effusion-synovitis in whole knee joint (p<0.01) and subpopliteal recess (p<0.05) was consistently associated with longitudinal changes in cartilage defects but not in cartilage volume and BMLs.

CONCLUSIONS

There are independent associations between knee joint effusion-synovitis and knee cartilage defects in both cross-sectional and longitudinal analyses, suggesting a potential causal relationship. The associations of effusion-synovitis with BMLs and cartilage volume were largely dependent on cartilage defects, suggesting potential causal pathways.

Electromechanical Assessment of Human Knee Articular Cartilage with Compression-Induced Streaming Potentials

PURPOSE

To assess the electromechanical properties of human knee articular cartilage with compression-induced streaming potentials for reliability among users and correlation with macroscopic and histological evaluation tools and sulfated glycosaminoglycan (sGAG) content.

METHODS

Streaming potentials are induced in cartilage in response to loading when mobile positive ions in the interstitial fluid temporarily move away from negatively charged proteoglycans. Streaming potential integrals (SPIs) were measured with an indentation probe on femoral condyles of 10 human knee specimens according to a standardized location scheme. Interobserver reliability was measured using an interclass correlation coefficient (ICC). The learning curves of 3 observers were evaluated by regression analysis. At each SPI measurement location the degradation level of the tissue was determined by means of the International Cartilage Repair Society (ICRS) score, Mankin score, and sGAG content.

RESULTS

The computed ICC was 0.77 (0.70-0.83) indicating good to excellent linear agreement of SPI values among the 3 users. A significant positive linear correlation of the learning index values was observed for 2 of the 3 users. Statistically significant negative correlations between SPI and both ICRS and Mankin scores were observed (r = 0.502, P < 0.001, and r = 0.255, P = 0.02, respectively). No correlation was observed between SPI and sGAG content (r = 0.004, P = 0.973).

CONCLUSIONS

SPI values may be used as a quantitative means of cartilage evaluation with sufficient reliability among users. Due to the significant learning curve, adequate training should be absolved before routine use of the technique.

Ulnar impaction syndrome: Managed by wrist arthroscopy

BACKGROUND

The development of handicraft industry and increase of various such works that need a large amount of repeated wrist ulnar deviation strength, the incidence of ulnar impaction syndrome (UIS) is increasing, but the traditional simple ulnar shortening osteotomy has more complications. This study aimed to explore the early diagnostic criteria of UIS and its wrist arthroscopic treatment experience.

MATERIALS AND METHODS

9 UIS patients were enrolled in this study. According to magnetic resonance imaging, X-ray and endoscopic features, the diagnostic criteria of UIS were summarized and the individualized treatment schedule was made. If the ulnar positive variance was less than 4 mm, the arthroscopic wafer resection was performed. If the ulnar positive variance was more than 4 mm, the arthroscopic resection of injury and degenerative triangular fibrocartilage complex and ulnar osteotomy were conducted.

RESULTS

In all patients, the wound healed without any complications. All patients returned to normal life and work, with no ulnar wrist pain again. One patient had wrist weakness. There was a significant difference of the wrist activity between the last followup and before operation (P < 0.05). According to the modified wrist function scoring system of Green and O'Brien, there were 6 cases of excellent, 2 cases of good and 1 case of appropriate and the overall excellent and good rate was 92.3%.

CONCLUSION

In the treatment of UIS, the arthroscopy can improve the diagnosis rate, optimize the treatment plan, shorten the treatment cycle, with good treatment results.

Accuracy of cartilage-specific 3-Tesla 3D-DESS magnetic resonance imaging in the diagnosis of chondral lesions: comparison with knee arthroscopy

Background

Arthroscopy is considered as “the gold standard” for the diagnosis of traumatic intraarticular knee lesions. However, recent developments in magnetic resonance imaging (MRI) now offer good opportunities for the indirect assessment of the integrity and structural changes of the knee articular cartilage. The study was to investigate whether cartilage-specific sequences on a 3-Tesla MRI provide accurate assessment for the detection of cartilage defects.

Methods

A 3-Tesla (3-T) MRI combined with three-dimensional double-echo steady-state (3D-DESS) cartilage specific sequences was performed on 210 patients with knee pain prior to knee arthroscopy. Sensitivity, specificity, and positive and negative predictive values of magnetic resonance imaging were calculated and correlated to the arthroscopic findings of cartilaginous lesions. Lesions were classified using the modified Outerbridge classification.

Results

For the 210 patients (1260 cartilage surfaces: patella, trochlea, medial femoral condyle, medial tibia, lateral femoral condyle, lateral tibia) evaluated, the sensitivities, specificities, positive predictive values, and negative predictive values of 3-T MRI were 83.3, 99.8, 84.4, and 99.8 %, respectively, for the detection of grade IV lesions; 74.1, 99.6, 85.2, and 99.3 %, respectively, for grade III lesions; 67.9, 99.2, 76.6, and 98.2 %, respectively, for grade II lesions; and 8.8, 99.5, 80, and 92 %, respectively, for grade I lesions.

Conclusions

For grade III and IV lesions, 3-T MRI combined with 3D-DESS cartilage-specific sequences represents an accurate diagnostic tool. For grade II lesions, the technique demonstrates moderate sensitivity, while for grade I lesions, the sensitivity is limited to provide reliable diagnosis compared to knee arthroscopy.

Accuracy of cartilage-specific 3-Tesla 3D-DESS magnetic resonance imaging in the diagnosis of chondral lesions: comparison with knee arthroscopy

BACKGROUND

Arthroscopy is considered as "the gold standard" for the diagnosis of traumatic intraarticular knee lesions. However, recent developments in magnetic resonance imaging (MRI) now offer good opportunities for the indirect assessment of the integrity and structural changes of the knee articular cartilage. The study was to investigate whether cartilage-specific sequences on a 3-Tesla MRI provide accurate assessment for the detection of cartilage defects.

METHODS

A 3-Tesla (3-T) MRI combined with three-dimensional double-echo steady-state (3D-DESS) cartilage specific sequences was performed on 210 patients with knee pain prior to knee arthroscopy. Sensitivity, specificity, and positive and negative predictive values of magnetic resonance imaging were calculated and correlated to the arthroscopic findings of cartilaginous lesions. Lesions were classified using the modified Outerbridge classification.

RESULTS

For the 210 patients (1260 cartilage surfaces: patella, trochlea, medial femoral condyle, medial tibia, lateral femoral condyle, lateral tibia) evaluated, the sensitivities, specificities, positive predictive values, and negative predictive values of 3-T MRI were 83.3, 99.8, 84.4, and 99.8 %, respectively, for the detection of grade IV lesions; 74.1, 99.6, 85.2, and 99.3 %, respectively, for grade III lesions; 67.9, 99.2, 76.6, and 98.2 %, respectively, for grade II lesions; and 8.8, 99.5, 80, and 92 %, respectively, for grade I lesions.

CONCLUSIONS

For grade III and IV lesions, 3-T MRI combined with 3D-DESS cartilage-specific sequences represents an accurate diagnostic tool. For grade II lesions, the technique demonstrates moderate sensitivity, while for grade I lesions, the sensitivity is limited to provide reliable diagnosis compared to knee arthroscopy.

Mapping tibiofemoral gonarthrosis: an MRI analysis of non-traumatic knee cartilage defects

OBJECTIVE

Arthroscopy is "the gold standard" for the diagnosis of knee cartilage lesions. However, it is invasive and expensive, and displays all the potential complications of an open surgical procedure. Ultra-high-field MRI now offers good opportunities for the indirect assessment of the integrity and structural changes of joint cartilage of the knee. The goal of the present study is to determine the site of early cartilaginous lesions in adults with non-traumatic knee pain.

METHODS

3-T MRI examinations of 200 asymptomatic knees with standard and three-dimensional double-echo steady-state (3D-DESS) cartilage-specific sequences were prospectively studied for early degenerative lesions of the tibiofemoral joint. Lesions were classified and mapped using the modified Outerbridge and modified International Cartilage Repair Society classifications.

RESULTS

A total of 1437 lesions were detected: 56.1% grade I, 33.5% grade II, 7.2% grade III and 3.3% grade IV. Cartographically, grade I lesions were most common in the anteromedial tibial areas; grade II lesions in the anteromedial L5 femoral areas; and grade III in the centromedial M2 femoral areas.

CONCLUSION

3-T MRI with standard and 3D-DESS cartilage-specific sequences demonstrated that areas predisposed to early osteoarthritis are the central, lateral and ventromedial tibial plateau, as well as the central and medial femoral condyle.

ADVANCES IN KNOWLEDGE

In contrast with previous studies reporting early cartilaginous lesions in the medial tibial compartment and/or in the medial femoral condyle, this study demonstrates that, regardless of grade, lesions preferentially occur at the L5 and M4 tibial and L5 and L2 femoral areas of the knee joint.

OARSI Clinical Trials Recommendations: Knee imaging in clinical trials in osteoarthritis

Significant advances have occurred in our understanding of the pathogenesis of knee osteoarthritis (OA) and some recent trials have demonstrated the potential for modification of the disease course. The purpose of this expert opinion, consensus driven exercise is to provide detail on how one might use and apply knee imaging in knee OA trials. It includes information on acquisition methods/techniques (including guidance on positioning for radiography, sequence/protocol recommendations/hardware for magnetic resonance imaging (MRI)); commonly encountered problems (including positioning, hardware and coil failures, sequences artifacts); quality assurance (QA)/control procedures; measurement methods; measurement performance (reliability, responsiveness, validity); recommendations for trials; and research recommendations.

The role of radiology in the evolution of the understanding of articular disease

Both the clinical practice of radiology and the journal Radiology have had an enormous effect on our understanding of articular disease. Early descriptions of osteoarthritis (OA) appeared in Radiology. More recently, advanced physiologic magnetic resonance (MR) techniques have furthered our understanding of the early prestructural changes in patients with OA. Sodium imaging, delayed gadolinium-enhanced MR imaging of cartilage, and spin-lattice relaxation in the rotating frame (or T1ρ) sequences have advanced understanding of the pathophysiology and pathoanatomy of OA. Many pioneering articles on rheumatoid arthritis (RA) also have been published in Radiology. In the intervening decades, our understanding of the natural history of RA has been altered by these articles. Many of the first descriptions of crystalline arthropathies, including gout, calcium pyrophosphate deposition, and hydroxyapatite deposition disease, appeared in Radiology.

Magnetic resonance imaging of osteophytic, chondral, and subchondral structures in a surgically-induced osteoarthritis rabbit model

OBJECTIVE

This study aimed to assess changes in osteophytic, chondral, and subchondral structures in a surgically-induced osteoarthritis (OA) rabbit model in order to correlate MRI findings with the macroscopic progress of OA and to define the timepoint for disease status in this OA model.

METHODS

The OA model was constructed by surgery in thirty rabbits with ten normal rabbits serving as controls (baseline). High-resolution three-dimensional MRI using a 1.5-T coil was performed at baseline, two, four, and eight weeks post-surgery. MRIs of cartilage lesions, subchondral bone lesions, and osteophyte formations were independently assessed by two blinded radiologists. Ten rabbits were sacrificed at baseline, two, four, and eight weeks post-surgery, and macroscopic evaluation was independently performed by two blinded orthopedic surgeons.

RESULTS

The signal intensities and morphologies of chondral and subchondral structures by MRI accurately reflected the degree of OA. Cartilage defects progressed from a grade of 0.05-0.15 to 1.15-1.30 to 1.90-1.97 to 3.00-3.35 at each successive time point, respectively (p<0.05). Subchondral bone lesions progressed from a grade of 0.00 to 0.78-0.90 to 1.27-1.58 to 1.95-2.23 at each successive time point, respectively (p = 0.000). Osteophytes progressed from a size (mm) of 0.00 to 0.87-1.06 to 1.24-1.87 to 2.21-3.21 at each successive time point, respectively (p = 0.000).

CONCLUSIONS

Serial observations revealed that MRI can accurately detect the progression of cartilage lesions and subchondral bone edema over an eight-week period but may not be accurate in detecting osteophyte sizes. Week four post-surgery was considered the timepoint between OA-negative and OA-positive status in this OA model. The combination of this OA model with MRI evaluation should provide a promising tool for the pre-clinical evaluation of new disease-modifying osteoarthritis drugs.

Diagnostic accuracy of noncontrast MRI for detection of glenohumeral cartilage lesions: a prospective comparison to arthroscopy

BACKGROUND

The purpose of this study was to determine the prevalence of glenohumeral articular cartilage lesions in patients with rotator cuff tendinopathy and to assess the accuracy of noncontrast magnetic resonance imaging (MRI) in detecting these defects compared with the "gold standard" of arthroscopy.

METHODS

Noncontrast MRI studies obtained in 84 consecutive patients undergoing shoulder arthroscopy for rotator cuff tendinopathy (mean age, 54.8 years; range, 17-82 years) were prospectively evaluated for glenohumeral cartilage lesions. Two fellowship-trained, experienced musculoskeletal radiologists were blinded from the arthroscopic findings and independently evaluated the glenoid and humeral head cartilage on 2 separate occasions.

RESULTS

At arthroscopy, cartilage lesions of the humeral head were detected in 23 patients (frequency, 27.4%), and glenoid cartilage lesions were found in 20 patients (frequency, 23.8%). For detection of a humeral lesion on MRI, the radiologists' combined accuracy was 78%, sensitivity was 43%, and specificity was 91%. The combined accuracy for detection of glenoid lesions on MRI was 84%, sensitivity was 53%, and specificity was 93%. Combining the readers, low-grade lesions (International Cartilage Repair Society grades 1 and 2) of the glenoid and humerus were read as negative on MRI in 63% and 86% of cases, respectively.

CONCLUSION

Overall accuracy of noncontrast MRI for detection of glenohumeral articular cartilage lesions is good; however, interpretation is reader dependent, and accuracy is significantly reduced for detection of low-grade lesions. On the basis of these findings, we recommend that patients with rotator cuff tendinopathy undergoing arthroscopy be informed that the presence and severity of cartilage lesions may be underestimated on MRI.

Glenohumeral articular cartilage lesions: prospective comparison of non-contrast magnetic resonance imaging and findings at arthroscopy

PURPOSE

The purpose of this study was to assess the diagnostic sensitivity, specificity, accuracy, negative predictive value (NPV), positive predictive value (PPV), and test-retest reliability of magnetic resonance imaging (MRI) for detecting cartilage abnormalities of the glenohumeral joint in comparison with the gold standard of diagnostic arthroscopy.

METHODS

Forty-four patients with a preoperative non-contrast MRI study of their affected shoulder underwent arthroscopy by one surgeon for rotator cuff tendinopathy from 2009 to 2010. Articular cartilage defects were prospectively recorded and graded according to the International Cartilage Repair Society classification system at the time of arthroscopy. One year after surgery, the preoperative MRI were reviewed by a board-certified radiologist and the treating surgeon for articular cartilage defects of both the humeral head and the glenoid. Sensitivity, specificity, accuracy, and test-retest reliability were calculated.

RESULTS

At arthroscopy, 43% of the shoulders were found to have articular cartilage defects. When the readers' findings were combined, the sensitivity of detecting humeral lesions on MRI was 32%; specificity, 80%; accuracy, 63%; PPV, 57%; and NPV, 66%. The sensitivity of detecting glenoid lesions was 31%; specificity, 86%; accuracy, 76%; PPV, 33%; and NPV, 85%.

CONCLUSIONS

This study finds that the overall accuracy of MRI in detecting articular cartilage damage in patients with the clinical diagnosis of subacromial pathology is moderate.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria based on consecutive patients with universally applied reference "gold" standard.

Subject-specific analysis of joint contact mechanics: application to the study of osteoarthritis and surgical planning

Advances in computational mechanics, constitutive modeling, and techniques for subject-specific modeling have opened the door to patient-specific simulation of the relationships between joint mechanics and osteoarthritis (OA), as well as patient-specific preoperative planning. This article reviews the application of computational biomechanics to the simulation of joint contact mechanics as relevant to the study of OA. This review begins with background regarding OA and the mechanical causes of OA in the context of simulations of joint mechanics. The broad range of technical considerations in creating validated subject-specific whole joint models is discussed. The types of computational models available for the study of joint mechanics are reviewed. The types of constitutive models that are available for articular cartilage are reviewed, with special attention to choosing an appropriate constitutive model for the application at hand. Issues related to model generation are discussed, including acquisition of model geometry from volumetric image data and specific considerations for acquisition of computed tomography and magnetic resonance imaging data. Approaches to model validation are reviewed. The areas of parametric analysis, factorial design, and probabilistic analysis are reviewed in the context of simulations of joint contact mechanics. Following the review of technical considerations, the article details insights that have been obtained from computational models of joint mechanics for normal joints; patient populations; the study of specific aspects of joint mechanics relevant to OA, such as congruency and instability; and preoperative planning. Finally, future directions for research and application are summarized.

Aggrecanases in the human synovial fluid at different stages of osteoarthritis

In vivo and in vitro aggrecanases degrade proteoglycan aggrecan in articular cartilage. However, the expression of aggrecanases in patients in different stages of osteoarthritis (OA) has not been investigated. This study detected the expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4) and ADAMTS-5 and their proteolytic products, ARGxx, in the synovial fluid (SF) of patients in different stages of OA. This study aimed to evaluate the expression of aggrecanases and to explore the respective roles of these enzymes in human cartilage degradation. A total of 144 patients with knee OA were divided into early-, middle-, and late-stage OA groups according to the degree of cartilage degradation using Recht's MRI grading standard and the modified Outerbridge classification system. Expression levels of ADAMTS-4, ADAMTS-5, and ARGxx in the SF from these patients were measured using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Our findings showed that ADAMTS-4 and ARGxx expression levels in the early-stage group were significantly higher than in the other two groups. ADAMTS-5 in the early-stage group and ADAMTS-4, ADAMTS-5, and ARGxx in the late-stage group were significantly higher than those in the middle-stage OA group. Both ADAMTS-4 and ADAMTS-5 levels were correlated with ARGxx levels (P < 0.05). The correlation coefficients of ADAMTS-4 and ADAMTS-5 were 0.236 and 0.068, 0.729 and 0.479, and 0.675 and 0.257 in the early-, middle-, and late-stage groups, respectively, and 0.530 and 0.258 in the total SF samples. Western blot analysis revealed that the ADAMTS-4 and ADAMTS-5 in SF were 50 kDa proteins and that ARGxx in SF had at least two molecular masses, 55 kDa and 70 kDa. The expression levels of all three proteins were consistent with the ELISA results. These results suggested that aggrecanases were involved in all stages of human OA aggrecan degradation, especially in the early and late stages. ADAMTS-4 levels were higher in early- compared with middle- or late-stage OA and were also more correlated with ARGxx than ADAMTS-5; thus, ADAMTS-4 might be the principal aggrecanase of aggrecan degradation in human OA.

The diagnostic performance of MRI in osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

Osteoarthritis (OA) is currently diagnosed using clinical and radiographic findings. In recent years magnetic resonance imaging (MRI) use in OA has increasingly been studied. This study was conducted to determine the diagnostic utility of MRI in OA through a meta-analysis of published studies.

METHODS

A systematic literature search was undertaken to include studies that used MRI to evaluate or detect OA. MRI was compared to various reference standards: histology, arthroscopy, radiography, CT, clinical evaluation, and direct visual inspection. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic (ROC) area under the curve (AUC) were calculated. Random-effects models were used to pool results.

RESULTS

Of 20 relevant studies identified from the literature, 16 reported complete data and were included in the meta-analysis, with a total of 1220 patients (1071 with OA and 149 without). Overall sensitivity from pooling data of all the included studies was 61% [95% confidence interval (CI) 53-68], specificity was 82% (95% CI 77-87), PPV was 85% (95% CI 80-88), and NPV was 57% (95% CI 43-70). The ROC showed an AUC of 0.804. There was significant heterogeneity in the above parameters (I(2)>83%). With histology as the reference standard, sensitivity increased to 74% and specificity decreased to 76% compared with all reference standards combined. When arthroscopy was used as the reference standard, sensitivity increased to 69% and specificity to 93% compared with all reference standards combined.

CONCLUSION

MRI can detect OA with an overall high specificity and moderate sensitivity when compared with various reference standards, thus lending more utility to ruling out OA than ruling it in. The sensitivity of MRI is below the current clinical diagnostic standards. At this time standard clinical algorithm for OA diagnosis, aided by radiographs appears to be the most effective method for diagnosing OA.

Value of sagittal fat-suppressed proton-density fast-spin-echo of the knee joint as a limited protocol in evaluating internal knee derangements

PURPOSE

The aim of the study was to determine the accuracy and observer agreement in the assessment of internal knee derangement using sagittal fat-suppressed proton-density fast-spin-echo (FS PD-FSE) compared with combined sagittal T1-weighted spin-echo, dual-proton-density, and T2-weighted spin-echo sequences and with arthroscopy.

METHODS

One hundred eighteen patients undergoing routine knee magnetic resonance (MR) imaging had additional imaging with sagittal FS PD-FSE sequences. Menisci, cruciate ligaments, extensor tendons (ETs), bone marrow, osteoarthritic changes, soft tissue edema, joint effusion, and incidental tumors were analyzed. Magnetic resonance images were independently reviewed by 2 radiologists. Fifty patients underwent knee arthroscopy. Statistical analysis compared both imaging protocols with each other and with arthroscopy. Intrareader and interreader agreements were evaluated using κ analysis. Both protocols were compared with arthroscopy.

RESULTS

Intrareader agreement was very high except for readings of the posterior cruciate ligament, ETs, and cartilage. Intrareader agreement did not differ significantly between the 2 readers except for ETs, bone marrow, and cartilage. Interreader percent agreements were high using both protocols and were not significantly different between the 2 readers except for posterior cruciate ligament. Compared with arthroscopy, both methods showed almost identical results regarding sensitivity, specificity, positive predictive value, and negative predictive value, except for cartilage where FS PD-FSE had increased sensitivity, whereas the combined protocol had increased specificity.

CONCLUSIONS

Sagittal FS PD-FSE is comparable to our regular MR protocol in assessing internal knee derangement with an overall agreement of at least 93% on all sites except cartilage. It was also comparable to arthroscopy in assessing the cruciate ligaments and menisci, but had a low specificity for cartilaginous derangements. It can replace our 3 sagittal series comprising T1- and T2-weighted and proton-density-spin-echo sequences, hence saving time and cost.

Evaluation of cartilage surface injuries using 3D-double echo steady state (3D-DESS): effect of changing flip angle from 40° to 90°

BACKGROUND

In magnetic resonance imaging (MRI) with 3D-double-echo steady-state (3D-DESS) sequences, the cartilage-synovial fluid contrast is reported to be better with a flip angle of 90° than with the conventional flip angle of 40°, and the detection rate of knee cartilage injury may be improved.

PURPOSE

To compare the diagnostic performance and certainty of diagnosis with 3D-DESS images made using two flip angle settings, 40° and 90°, for knee cartilage surface lesions of Grade 2 or above confirmed by arthroscopy.

MATERIAL AND METHODS

Images were obtained with 3D-DESS flip angles of 40° and 90° at 1.0T in 13 consecutive patients (2 men, 11 women, age range 18-68 years) evaluated for superficial cartilage injury by arthroscopy. Two radiologists classified the presence or absence of cartilage damage of ≥Grade 2 as 'positive (p)' or 'negative (n)', respectively. The rate of agreement with arthroscopic diagnosis was then examined, and the diagnostic performance compared. Diagnostic confidence was assessed scoring the presence or absence of cartilage damage into three categories: 3 = can diagnose with absolute confidence; 2 = can diagnose with a level of certainty as probably present or probably absent; and 1 = cannot make a diagnosis.

RESULTS

In a comparison of the rate of agreement between diagnosis by 3D-DESS images and arthroscopy, the rate of agreement was significantly higher and diagnostic performance was better in 90° images for the medial femoral condyle only. Diagnostic confidence was significantly better with 90° flip angle images than with 40° flip angle images for all six cartilage surfaces.

CONCLUSION

In evaluating knee cartilage surface lesions with 3D-DESS sequences, a flip angle setting of 90° is more effective than the conventional setting of 40°.

Evaluation of bee venom and hyaluronic acid in the intra-articular treatment of osteoarthritis in an experimental rabbit model

The aim of this study was to investigate bee venom and hyaluronic acid in the intra-articular treatment of osteoarthritis in an experimental rabbit model. Forty-five rabbits were used and they were randomly divided into three groups (BVI, BVII, and HA) and each group was divided to two subgroups to evaluate the radiologic, magnetic resonance imaging, histopathologic, and biochemical evaluation in post treatment second week (a) and twelfth week (b). Radiologically, a significant difference was observed in the HA group (P<0.05). The MRI evaluation of at any time in group BVI(b) was found to be different. No significant differences were seen between the groups, biochemically. Histopathologically, cellularity, and orthochromasia was evident with Safranin-O in the BVI(b) and BVII(a); adhesions were seen in the BVII(a) group and clustering of chondrocyte in the HA(b) group were found to be different. Consequently, intra-articular application of HA and BV for experimental model of osteoarthritis has no significant influence upon recovery after therapy.

The evolution of articular cartilage imaging and its impact on clinical practice

Over the past four decades, articular cartilage imaging has developed rapidly. Imaging now plays a critical role not only in clinical practice and therapeutic decisions but also in the basic research probing our understanding of cartilage physiology and biomechanics.

Routine 3D magnetic resonance imaging of joints

Due to its high spatial resolution and excellent tissue contrast, magnetic resonance imaging (MRI) has become the most commonly used imaging method to evaluate joints. Most musculoskeletal MRI is performed using 2D fast spin-echo sequences. However, 3D sequences have also been used for joint imaging and have the advantage of acquiring thin continuous slices through joints, which reduces the effects of partial volume averaging. With recent advances in MR technology, 3D sequences with isotropic resolution have been developed. These sequences allow high-quality multiplanar reformat images to be obtained following a single acquisition, thereby eliminating the need to repeat sequences with identical tissue contrast in different planes. Preliminary results on the diagnostic performance of 3D isotropic resolution sequences are encouraging. However, additional studies are needed to determine whether these sequences can replace currently used 2D fast spin-echo sequences for providing comprehensive joint assessment in clinical practice.

Remodeling of articular cartilage and subchondral bone after bone grafting and matrix-associated autologous chondrocyte implantation for osteochondritis dissecans of the knee

BACKGROUND

Osteochondritis dissecans (OCD) of the knee is a challenging problem. Previously, the authors implemented a novel 1-step surgical procedure for OCD treatment consisting of matrix-associated autologous chondrocyte implantation (ACI) and simultaneous bone reconstruction including the subchondral lamina.

PURPOSE

This study presents the 2-to 5-year results after this technique, assessing correlations of clinical function and cartilage and bone remodeling processes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-six patients with symptomatic condylar knee OCD (International Cartilage Repair Society OCD III/IV) were treated with matrix-associated ACI and monocortical cancellous cylinders for defect filling and subchondral bone plate reconstruction using cortical graft layers as novel subchondral lamina. Evaluations were performed with clinical rating scales and 1.5-T magnetic resonance imaging using the magnetic resonance observation of cartilage repair tissue (MOCART) score and a newly implemented subchondral lamina remodeling grade.

RESULTS

The defect size was 5.3 ± 2.3 cm(2). The defect depth was 8.7 ± 2.4 mm. After a follow-up of 39.8 ± 12.0 months, all scores improved significantly. Nineteen patients (73%) reached good/excellent results in the Lysholm-Gillquist score (preoperatively: 53.2 ± 18.0 points; latest follow-up: 88.5 ± 9.5 points) and the Cincinnati knee rating score (preoperatively: 51.7 ± 13.0 points; latest follow-up: 84.6 ± 11.7 points) and significant improvements in the subjective International Knee Documentation Committee (IKDC) score by 27.9% (preoperatively: 50.5% ± 16.1%; latest follow-up: 78.4% ± 13.4%). The MOCART score reached 62.4 ± 18.9 points. The clinical improvement and tissue remodeling occurred simultaneously and timed; thus, the cartilage defect filling and the lamina remodeling grades correlated significantly with each other, the follow-up time, and almost all clinical scores.

CONCLUSION

The simultaneous reconstruction of deep osteochondral defects of the knee OCD with monocortical cancellous cylinders and matrix-associated ACI is a biological, 1-step alternative to osteochondral cylinder transfer or conventional ACI that leads to good clinical and magnetic resonance imaging results after an intermediate follow-up period. The present study demonstrated simultaneous remodeling processes of articular cartilage repair tissue and subchondral lamina; this synchronization is not yet understood and deserves further investigation.