T1ρ mapping of articular cartilage grafts after autologous osteochondral transplantation for osteochondral lesions of the talus: A longitudinal evaluation

Quantitative assessment of anterior talofibular ligament quality in chronic lateral ankle instability using magnetic resonance imaging T2* value

OBJECTIVE

To determine T2* normal reference values for anterior talofibular ligament (ATFL) and to investigate the feasibility of the quantitative ATFL quality evaluation in chronic lateral ankle instability (CLAI) using T2* values.

MATERIALS AND METHODS

This study enrolled 15 patients with CLAI and 30 healthy volunteers. The entire ATFL T2* values from the MRI T2* mapping were measured. The prediction equation (variables: age, height, and weight) in a multiple linear regression model was used to calculate the T2* normal reference value in the healthy group. T2* ratio was defined as the ratio of the actual T2* value of the patient's ATFL to the normal reference value for each patient. A Telos device was used to measure the talar tilt angle (TTA) from the stress radiograph.

RESULTS

T2* values of ATFL in the healthy and CLAI groups were 10.82 ± 1.84 ms and 14.36 ± 4.30 ms, respectively, which are significantly higher in the CLAI group (P < 0.05). The prediction equation of the normal reference T2* value was [14.9 + 0.14 × age (years) - 4.7 × height (m) - 0.03 × weight (kg)] (R2 = 0.65, P < 0.0001). A significant positive correlation was found between the T2* ratio and TTA (r = 0.66, P = 0.007).

CONCLUSION

MRI T2* values in patients with CLAI were higher than those in healthy participants, and the T2* ratio correlated with TTA, suggesting that T2* values are promising for quantitative assessment of ATFL quality preoperatively.

Presurgical and Postsurgical MRI Evaluation of Osteochondral Lesions of the Foot and Ankle: A Primer

The gold standard diagnostic imaging tool for ankle OCLs is magnetic resonance imaging, which allows precise evaluation of the articular cartilage and assessment of the surrounding soft tissue structures. Post-operative morphologic MRI assessment via MOCART scores provide semi-quantitative analysis of the repair tissue, but mixed evidence exists regarding its association with post-operative outcomes. Post-operative biochemical MRIs allow assessment of the collagen network of the articular cartilage via T2-mapping and T2∗ mapping, and assessment of the articular glycosaminoglycan content via delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T1rho mapping and sodium imaging.

Correlation of Postoperative Imaging With MRI and Clinical Outcome After Cartilage Repair of the Ankle: A Systematic Review and Meta-analysis

Background:

Magnetic resonance imaging (MRI) is commonly used for evaluation of ankle cartilage repair, yet its association with clinical outcome is controversial. This study analyzes the correlation between MRI and clinical outcome after cartilage repair of the talus including bone marrow stimulation, cell-based techniques, as well as restoration with allo- or autografting.

Methods:

A systematic search was performed in MEDLINE, Embase, and Cochrane Collaboration. Articles were screened for correlation of MRI and clinical outcome. Guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) were used. Chi-square test and regression analysis were performed to identify variables that determine correlation between clinical and radiologic outcome.

Results:

Of 2687 articles, a total of 43 studies (total 1212 cases) were included with a mean Coleman score of 57 (range, 33-70). Overall, 93% were case series, and 5% were retrospective and 2% prospective cohort studies. Associations between clinical outcome and ≥1 imaging variable were found in 21 studies (49%). Of 24 studies (56%) using the composite magnetic resonance observation of cartilage repair tissue (MOCART) score, 7 (29%) reported a correlation of the composite score with clinical outcome. Defect fill was associated with clinical outcome in 5 studies (12%), and 5 studies (50%) reported a correlation of T2 mapping and clinical outcome. Advanced age, shorter follow-up, and larger study size were associated with established correlation between clinical and radiographic outcome (P = .021, P = .028, and P = .033).

Conclusion:

Interpreting MRI in prediction of clinical outcome in ankle cartilage repair remains challenging; however, it seems to hold some value in reflecting clinical outcome in patients with advanced age and/or at a shorter follow-up. Yet, further research is warranted to optimize postoperative MRI protocols and assessments allowing for a more comprehensive repair tissue evaluation, which eventually reflect clinical outcome in patients after cartilage repair of the ankle.

Level of Evidence: Level III, systematic review and meta-analysis.

Location Distribution of 2,087 Osteochondral Lesions of the Talus

OBJECTIVE

The primary aim of this study was to evaluate the exact location distribution in patients with osteochondral lesions of the talus (OLTs) using a 9-grid scheme. The secondary aim is to match lesion location to lesion size, arthroscopic or open operation, and trauma occurrence.

METHODS

A systematic review was performed in the databases PubMed, EMBASE, and Cochrane. Search terms consisted of "talus" and "osteochondral lesion." Two independent reviewers evaluated search results and conducted the quality assessment using the Methodological Index for Non-Randomized Studies (MINORS). Primary outcome measure was OLT location in the 9 zone-grid. Secondary outcome measures were OLT size in 9-zones, preoperative radiological modality use, demographic lesion size variables as well as open or arthroscopic treatment.

RESULTS

Fifty-one articles with 2,087 OLTs were included. Heterogeneity concerning methodological nature was observed and methodological quality was low. The posteromedial (28%) and centromedial (31%) zones combined as one location was the location with the highest incidence of OLTs with a rate of 59%. Individual OLT size was reported for only 153 lesions (7%). Preoperative combination of X-ray and magnetic resonance imaging (MRI), and/or computed tomography (CT) was reported in 20 studies (43%). Trauma was reported in 78% of patients. Furthermore, 67% was treated arthroscopically and 76% received primary OLT treatment.

CONCLUSION

The majority of OLTs are located in the posteromedial and centromedial zone, while the largest OLTs were reported in the centrocentral zone. Further research is required to identify the prognostic impact of location occurrence on the outcomes following OLT treatment.

Overexpression of long non-coding RNA AP001505.9 inhibits human hyaline chondrocyte dedifferentiation

Autologous chondrocyte implantation (ACI) is an effective method for treating chronic articular cartilage injury and degeneration; however, it requires large numbers of hyaline chondrocytes, and human hyaline chondrocytes often undergo dedifferentiation in vitro. Moreover, although long non-coding RNAs (lncRNAs) regulate gene expression in many pathological and physiological processes, their role in human hyaline chondrocyte dedifferentiation remains unclear. Here, we examined lncRNA and mRNA expression profiles in human hyaline chondrocyte dedifferentiation using microarray analysis. Among the many lncRNAs and mRNAs that showed differential expression, lncRNA AP001505.9 (ENST00000569966) was significantly downregulated in chondrocytes after dedifferentiation. We next performed gene ontology, pathway, and CNC (coding-non-coding gene co-expression) analyses to investigate potential regulatory mechanisms for AP001505.9. Pellet cultures were then used to redifferentiate dedifferentiated chondrocytes, and AP001505.9 expression was upregulated after redifferentiation. Finally, both in vitro and in vivo experiments demonstrated that AP001505.9 overexpression inhibited dedifferentiation of chondrocytes. This study characterizes lncRNA expression profiles in human hyaline chondrocyte dedifferentiation, thereby identifying new potential mechanisms of chondrocyte dedifferentiation worthy of further investigation.

T1rho and T2 mapping of ankle cartilage of female and male ballet dancers

BACKGROUND

Since ballet dancers begin their training before skeletal maturity, accurate and non-invasive identification of cartilage diseases is clinically important. Angle-dependent analysis of T1rho and T2 sequences can be useful for quantification of the composition of cartilage.

PURPOSE

To investigate the angle-dependent T1rho and T2 profiles of ankle cartilage in non-dancers and dancers.

MATERIAL AND METHODS

Ten female non-dancers, ten female dancers, and 9 male dancers were evaluated using T1rho and T2 mapping sequences. Manual segmentation of talar and tibial cartilage on these images was performed by two radiologists. Inter- and intra-rater reliabilities were calculated using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Mean thickness and volume of cartilage were estimated. Angle-dependent relaxation time profiles of talar and tibial cartilage were created.

RESULTS

ICCs of the number of segmented pixels were poor to excellent. Bland-Altman plots indicated that differences were associated with segment sizes. Segmented cartilage on T1rho demonstrated larger thickness and volume than those on T2 in all populations. Male dancers showed larger cartilage thickness and volume than female dancers and non-dancers. Each cartilage demonstrated angular-dependent T1rho and T2 profiles. Minimal T1rho and T2 values were observed at approximately 180°-200°; higher values were seen at the angle closer to the magic angle. Minimal T2 value of talar cartilage of dancers was larger than that of non-dancers.

CONCLUSION

In this small cohort study, regional and sex variations of ankle cartilage T1rho and T2 values in dancers and non-dancers were demonstrated using an angle-dependent approach.