Does Injection of Hyaluronic Acid Protect Against Early Cartilage Injury Seen After Marathon Running? A Randomized Controlled Trial Utilizing High-Field Magnetic Resonance Imaging

Imaging of joint response to exercise with MRI and PET

Imaging of the joint in response to loading stress may provide additional measures of joint structure and function beyond conventional, static imaging studies. Exercise such as running, stair climbing, and squatting allows evaluation of the joint response to larger loading forces than during weight bearing. Quantitative MRI (qMRI) may assess properties of cartilage and meniscus hydration and organization in vivo that have been investigated to assess the functional response of these tissues to physiological stress. [18F]sodium fluoride ([18F]NaF) interrogates areas of newly mineralizing bone and provides an opportunity to study bone physiology, including perfusion and mineralization rate, as a measure of joint loading stress. In this review article, methods utilizing quantitative MRI, PET, and hybrid PET-MRI systems for assessment of the joint response to loading from exercise in vivo are examined. Both methodology and results of various studies performed are outlined and discussed. Lastly, the technical considerations, challenges, and future opportunities for these approaches are addressed.

Multifunctional polysaccharide nanoprobes for biological imaging

Imaging and tracking biological targets or processes play an important role in revealing molecular mechanisms and disease states. Bioimaging via optical, nuclear, or magnetic resonance techniques enables high resolution, high sensitivity, and high depth imaging from the whole animal down to single cells via advanced functional nanoprobes. To overcome the limitations of single-modality imaging, multimodality nanoprobes have been engineered with a variety of imaging modalities and functionalities. Polysaccharides are sugar-containing bioactive polymers with superior biocompatibility, biodegradability, and solubility. The combination of polysaccharides with single or multiple contrast agents facilitates the development of novel nanoprobes with enhanced functions for biological imaging. Nanoprobes constructed with clinically applicable polysaccharides and contrast agents hold great potential for clinical translations. This review briefly introduces the basics of different imaging modalities and polysaccharides, then summarizes the recent progress of polysaccharide-based nanoprobes for biological imaging in various diseases, emphasizing bioimaging with optical, nuclear, and magnetic resonance techniques. The current issues and future directions regarding the development and applications of polysaccharide nanoprobes are further discussed.

Age-Related Changes in the Spatial Variation of Magnetic Susceptibility of Human Articular Cartilage

BACKGROUND

Quantitative susceptibility mapping (QSM) has shown great potential for revealing the layer structure of articular cartilage based on the laminar susceptibility difference at different depths. However, more information is needed on the effects of age on the spatial distribution of magnetic susceptibility in human cartilage.

PURPOSE

To assess the ability of QSM to quantify the age-related differences in depth-wise cartilage susceptibility values in healthy populations.

STUDY TYPE

Prospective.

POPULATION

A total of 94 healthy asymptomatic subjects in three age cohorts: 19-30 (n = 36, 20 males), 31-50 (n = 45, 27 males), and 51-66 years (n = 13, 7 males).

FIELD STRENGTH/SEQUENCE

3D gradient echo sequences at 3.0 T.

ASSESSMENT

Four cartilage compartments were analyzed, including the central lateral/medial femur (cLF/cMF) and the lateral/medial tibia (LT/MT). The spatial susceptibility profile and the corresponding 95% confidence interval (CI) of each age cohort were obtained as functions of the normalized distance from the bone-cartilage interface to the cartilage surface (cartilage depth from 0.0 to 1.0).

STATISTICAL TESTS

The relationship between age and cartilage thickness of each cartilage subregion was tested by Pearson correlation with P < 0.05 considered significant. Cartilage depths with separations of 95% CIs were considered to have significant susceptibility differences between two age cohorts with a Bonferroni-corrected P < 0.05.

RESULTS

The cartilage thickness did not change significantly with age (P value range: 0.06-0.85). Susceptibilities were significantly higher in the 51-66-year-olds compared with the 31-50-year-olds in the deep layer of cMF (cartilage depth: 0.0-0.22) and LT (0.05-0.28). Susceptibilities were significantly higher in the 51-66-year-olds compared with the 19-30-year-olds near the cartilage-bone interface of cMF (0.0-0.34), cLF (0.0-0.28), and LT (0.0-0.58). There were also significantly higher susceptibilities in the 31-50-year-olds compared with the 19-30-year-olds in the deeper regions of cMF (0.26-0.57), cLF (0.0-0.40), and LT (0.07-0.80).

DATA CONCLUSION

Age-related susceptibility changes in the deeper regions of knee cartilage were observed using QSM.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Variation characteristics of stress distribution in the subchondral bone of the knee joint of judo athletes with long-term stress changes

OBJECTIVE

To investigate the distribution of bone density in the subchondral bone tissue of the knee joint due to the mechanical stress load generated by judo, the bone tissue volume of different densities and the bone remodeling characteristics of the subchondral bone of the knee joint.

METHODS

CT imaging data of the knee joint were collected from 15 healthy individuals as controls and 15 elite judo athletes. Firstly, they were processed by the CTOAM technique, and secondly, the distribution pattern of high-density areas of the knee joint was localized using nine anatomical regions. In addition, three tomographic images were selected in the sagittal, coronal, and axial 2D image windows to observe the distribution of different densities of bone tissue. Finally, the percentage of bone tissue volume (%BTV) and bone remodeling trend of bone tissues with different densities were determined.

RESULTS

In this study, high-density areas were found in the 4th, 5th, and 6th regions of the articular surface of the distal femur and the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th and 8th regions of the tibial plateau in judo athletes; the distribution of high-density areas on the articular surface of the distal femur in control subjects was similar with judo athletes, and high-density areas were mainly found in the 4th and 5th regions of the tibial plateau. The %BTV of low (401-500HU in the distal femur; 301-400 HU and 401-500HU in the tibial plateau), moderate, and high bone density was higher in judo athletes than in controls in the subchondral bone of the distal femur and tibial plateau (P< 0.05).

CONCLUSION

The history of compressive stresses, struck stresses, soft tissue tension and pull, self-gravity and intra-articular stress loading generated by the lower limb exercise technique of judo leads to specific forms of stress distribution and bone tissue remodeling in the subchondral bone tissue within the distal femur and tibia plateau.

The Influence of Running on Lower Limb Cartilage: A Systematic Review and Meta-analysis

BACKGROUND

Running is a popular activity practiced worldwide. It is important to understand how running affects joint health to provide recommendations to sports medicine practitioners and runners.

OBJECTIVE

Our aim was to summarize the influence of running on lower limb cartilage morphology and composition using quantitative magnetic resonance imaging (MRI).

METHODS

Prospective repeated-measures studies evaluating cartilage using MRI before and after running were included. Data sources included Pubmed, Embase, CINAHL, SportDiscus, Web of Science, and Cochrane Central Registry of Controlled Trials. Qualitative analyses considered the number and methodological quality ratings of studies based on the QualSyst tool, and recommendations were based on the strength of evidence (strong, moderate, limited, or very limited). Quantitative analysis involved meta-analyses, for which effect sizes were calculated as Hedge's g standardized mean differences.

RESULTS

We included 43 articles, assessing seven outcomes (lesions, volume, thickness, glycosaminoglycan content, and T1ρ, T2, and T2* relaxation times). Nineteen articles were rated as high quality, 24 were rated as moderate quality, and none were rated as low quality. Qualitative analyses suggest that running may cause an immediate reduction in knee cartilage volume, thickness, as well as T1ρ and T2 relaxation times immediately; however, these changes did not persist. Meta-analyses revealed a small and moderate decrease immediately following a single running bout in T2 relaxation time in the medial femur and tibia, respectively. Qualitative analyses indicated that the influence of repeated exposure to running on cartilage morphology and composition was limited. Despite conflicting evidence regarding pre-existing knee cartilage lesions, moderate evidence suggests that running does not lead to the formation of new lesions. Repeated running exposure did not cause changes to foot and ankle cartilage thickness or composition.

CONCLUSIONS

Changes to lower limb cartilage following running are transient. Immediate changes to cartilage morphology and composition, which likely reflect natural fluid dynamics, do not persist and were generally not significant when pooled statistically. Results suggest that cartilage recovers well from a single running bout and adapts to repeated exposure. Given that moderate evidence indicates that running does not lead to new lesions, future trials should focus on clinical populations, such as those with osteoarthritis.

TRIAL REGISTRATION

Not applicable.

Change in Susceptibility Values in Knee Cartilage After Marathon Running Measured Using Quantitative Susceptibility Mapping

BACKGROUND

Quantitative susceptibility mapping (QSM) has been used to study the magnetic susceptibility properties of collagen fibers in articular cartilage; however, it is unclear whether QSM is sensitive to changes due to degradation caused by long-distance running. It is clinically important to understand the link between long-distance running and microstructural changes in knee cartilage.

PURPOSE

To investigate the ability of QSM to assess microstructural changes within cartilage after repetitive loading.

STUDY TYPE

Prospective.

POPULATION

Thirteen recreational, male long-distance runners.

FIELD STRENGTH/SEQUENCE

Three-dimensional gradient recalled echo acquired at 3 T.

ASSESSMENT

Magnetic resonance imaging (MRI) and 3D kinematics (translations and rotations during treadmill walking and running) of the knee joint were collected before and after marathon running. The compartments for analysis included the patella, trochlea, and subregions of femoral and tibial cartilage. Changes in regional susceptibility and cartilage thickness were calculated after marathon running. A susceptibility profile was obtained by fitting susceptibility as a function of the normalized depth of cartilage from the superficial to deep layers.

STATISTICAL TESTS

Paired t-test or Wilcoxon signed-rank test, 95% confidence interval (CI) of the depth-wise susceptibility profile, Pearson correlation or Spearman correlation.

RESULTS

There was a statistically significant increase in susceptibility value in the weight-bearing region of central medial femoral cartilage (cMF-c) after marathon running (pre-marathon: -0.0219 ± 0.0151 ppm, post-marathon: -0.0070 ± 0.0213 ppm, P < 0.05), while the cartilage thickness did not show significant changes in any regions (P-value range: 0.068-0.963). Significant susceptibility elevations occurred in the middle and deep layers of cMF-c (95% CIs did not overlap). A trend toward a positive correlation was found between the changes in susceptibility value in cMF-c and proximal-distal translation of the knee joint during walking (r = 0.55, P = 0.101) and running (r = 0.57, P = 0.089).

DATA CONCLUSION

Localized magnetic susceptibility alterations were observed within knee cartilage in the weight-bearing area after repetitive loading without any morphologic changes.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Host Response to Biomaterials for Cartilage Tissue Engineering: Key to Remodeling

Biomaterials play a core role in cartilage repair and regeneration. The success or failure of an implanted biomaterial is largely dependent on host response following implantation. Host response has been considered to be influenced by numerous factors, such as immune components of materials, cytokines and inflammatory agents induced by implants. Both synthetic and native materials involve immune components, which are also termed as immunogenicity. Generally, the innate and adaptive immune system will be activated and various cytokines and inflammatory agents will be consequently released after biomaterials implantation, and further triggers host response to biomaterials. This will guide the constructive remolding process of damaged tissue. Therefore, biomaterial immunogenicity should be given more attention. Further understanding the specific biological mechanisms of host response to biomaterials and the effects of the host-biomaterial interaction may be beneficial to promote cartilage repair and regeneration. In this review, we summarized the characteristics of the host response to implants and the immunomodulatory properties of varied biomaterial. We hope this review will provide scientists with inspiration in cartilage regeneration by controlling immune components of biomaterials and modulating the immune system.