Cartilage repair of the knee with Hyalograft C:® magnetic resonance imaging assessment of the glycosaminoglycan content at midterm

Highlights on Advancing Frontiers in Tissue Engineering

The field of tissue engineering continues to advance, sometimes in exponential leaps forward, but also sometimes at a rate that does not fulfill the promise that the field imagined a few decades ago. This review is in part a catalog of success in an effort to inform the process of innovation. Tissue engineering has recruited new technologies and developed new methods for engineering tissue constructs that can be used to mitigate or model disease states for study. Key to this antecedent statement is that the scientific effort must be anchored in the needs of a disease state and be working toward a functional product in regenerative medicine. It is this focus on the wildly important ideas coupled with partnered research efforts within both academia and industry that have shown most translational potential. The field continues to thrive and among the most important recent developments are the use of three-dimensional bioprinting, organ-on-a-chip, and induced pluripotent stem cell technologies that warrant special attention. Developments in the aforementioned areas as well as future directions are highlighted in this article. Although several early efforts have not come to fruition, there are good examples of commercial profitability that merit continued investment in tissue engineering. Impact statement Tissue engineering led to the development of new methods for regenerative medicine and disease models. Among the most important recent developments in tissue engineering are the use of three-dimensional bioprinting, organ-on-a-chip, and induced pluripotent stem cell technologies. These technologies and an understanding of them will have impact on the success of tissue engineering and its translation to regenerative medicine. Continued investment in tissue engineering will yield products and therapeutics, with both commercial importance and simultaneous disease mitigation.

Prospective Multiparametric Magnetic Resonance Monitoring of Changes in Lesions of Hyaline Cartilage of the Knee Joint After Treatment by Microfractures and Implantation of Biological Collagen Type I Matrix Implants

RATIONALE AND OBJECTIVES

This study's aims were to depict changes in cartilage quality after surgical intervention using magnetic resonance (MR) examination and in content of glycosaminoglycans chains (GAGs) after two types of surgeries - chondral defect treatment by microfractures and scaffold implantation in combination with microfractures.

MATERIALS AND METHODS

Twenty-five patients were studied: 14 with implants, 11 with microfractures. MR examination was made before surgery and 6, 12, and 18 months thereafter. Qualitative changes in cartilage were observed by means of delayed gadolinium enhanced magnetic resonance imaging of cartilage sequence using Gd-DTPA2- and Gd-DOTA. In each examination, GAGs content was determined at three locations: the defect, its surroundings, and a non-load-bearing reference area.

RESULTS

Measured indices showed no statistically significant differences in changes within the defect area when comparing the two treatment types at individual time points of 6, 12, and 18 months. In the case of microfracture treatment, more substantial decrease in GAGs concentration occurred at month 6, whereas the greatest decline occurred at month 12 when using an implant. Change in GAGs content and decline in cartilage quality were substantial also in the reference area and close surroundings.

CONCLUSIONS

Hyaline cartilage behaves as a unified whole, and change in GAGs content was marked also in locations with no morphological damage. Over the monitored period, no statistically significant difference between treatment types was noted as measured by GAGs content in the defect or its close surroundings. dGEMRIC is suitable for monitoring cartilage quality even if use of Gd-DTPA2- is not possible, because comparable results were achieved using Gd-DOTA.

[Update cartilage imaging of the small joints : Focus on high-field MRI]

BACKGROUND

Cartilage imaging of small joints is increasingly of interest, as early detection of cartilage damage may be relevant regarding individualized surgical therapies and long-term outcomes.

PURPOSE

The aim of this review is to explain modern cartilage imaging of small joints with emphasis on MRI and to discuss the role of methods such as CT arthrography as well as compositional and high-field MRI.

MATERIALS AND METHODS

A PubMed literature search was performed for the years 2008-2018.

RESULTS

Clinically relevant cartilage imaging to detect chondral damage in small joints remains challenging. Conventional MRI at 3 T can still be considered as a reference for cartilage imaging in clinical routine. In terms of sensitivity, MR arthrography (MR-A) and computed tomography arthrography (CT-A) are superior to non-arthrographic MRI at 1.5 T in the detection of chondral damage. Advanced degenerative changes of the fingers and toes are usually sufficiently characterized by conventional radiography. MRI at field strengths of 3 T and ultrahigh-field imaging at 7 T can provide additional quantifiable, functional and metabolic information.

CONCLUSION

Standardized cartilage imaging plays an important role in clinical diagnostics in the ankle joint due to the availability of different and individualized therapeutic concepts. In contrast, cartilage imaging of other small joints as commonly performed in clinical studies has not yet become standard of care in daily clinical routine. Although individual study results are promising, additional studies with large patient collectives are needed to validate these techniques. With rapid development of new treatment concepts radiological diagnostics will play a more significant role in the diagnosis of cartilage lesions of small joints.

Relationship Between Quantitative MRI Biomarkers and Patient-Reported Outcome Measures After Cartilage Repair Surgery: A Systematic Review

Background

Treatment of articular cartilage injuries remains a clinical challenge, and the optimal tools to monitor and predict clinical outcomes are unclear. Quantitative magnetic resonance imaging (qMRI) allows for a noninvasive biochemical evaluation of cartilage and may offer advantages in monitoring outcomes after cartilage repair surgery.

Hypothesis

qMRI sequences will correlate with early pain and functional measures.

Study Design

Systematic review; Level of evidence, 3.

Methods

A PubMed search was performed with the following search terms: knee AND (cartilage repair OR cartilage restoration OR cartilage surgery) AND (delayed gadolinium-enhanced MRI OR t1-rho OR T2 mapping OR dgemric OR sodium imaging OR quantitative imaging). Studies were included if correlation data were included on quantitative imaging results and patient outcome scores.

Results

Fourteen articles were included in the analysis. Eight studies showed a significant relationship between quantitative cartilage imaging and patient outcome scores, while 6 showed no relationship. T2 mapping was examined in 11 studies, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) in 4 studies, sodium imaging in 2 studies, glycosaminoglycan chemical exchange saturation transfer (gagCEST) in 1 study, and diffusion-weighted imaging in 1 study. Five studies on T2 mapping showed a correlation between T2 relaxation times and clinical outcome scores. Two dGEMRIC studies found a correlation between T1 relaxation times and clinical outcome scores.

Conclusion

Multiple studies on T2 mapping, dGEMRIC, and diffusion-weighted imaging showed significant correlations with patient-reported outcome measures after cartilage repair surgery, although other studies showed no significant relationship. qMRI sequences may offer a noninvasive method to monitor cartilage repair tissue in a clinically meaningful way, but further refinements in imaging protocols and clinical interpretation are necessary to improve utility.

Delayed gadolinium-enhanced MRI of cartilage and T2 mapping for evaluation of reparative cartilage-like tissue after autologous chondrocyte implantation associated with Atelocollagen-based scaffold in the knee

OBJECTIVE

To elucidate the quality of tissue-engineered cartilage after an autologous chondrocyte implantation (ACI) technique with Atelocollagen gel as a scaffold in the knee in the short- to midterm postoperatively, we assessed delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) and T2 mapping and clarified the relationship between T1 and T2 values and clinical results.

MATERIALS AND METHODS

In this cross-sectional study, T1 and T2 mapping were performed on 11 knees of 8 patients (mean age at ACI, 37.2 years) with a 3.0-T MRI scanner. T1implant and T2implant values were compared with those of the control cartilage region (T1control and T2control). Lysholm scores were also assessed for clinical evaluation. The relationships between the T1 and T2 values and the clinical Lysholm score were also assessed.

RESULTS

There were no significant differences in the T1 values between the T1implant (386.64 ± 101.78 ms) and T1control (375.82 ± 62.89 ms) at the final follow-up. The implants showed significantly longer T2 values compared to the control cartilage (53.83 ± 13.89 vs. 38.21 ± 4.43 ms). The postoperative Lysholm scores were significantly higher than the preoperative scores. A significant correlation was observed between T1implant and clinical outcomes, but not between T2implant and clinical outcomes.

CONCLUSION

Third-generation ACI implants might have obtained an almost equivalent glycosaminoglycan concentration compared to the normal cartilage, but they had lower collagen density at least 3 years after transplantation. The T1implant value, but not the T2 value, might be a predictor of clinical outcome after ACI.

Cartilage tissue engineering: From biomaterials and stem cells to osteoarthritis treatments

Articular cartilage is a non-vascularized and poorly cellularized connective tissue that is frequently damaged as a result of trauma and degenerative joint diseases such as osteoarthrtis. Because of the absence of vascularization, articular cartilage has low capacity for spontaneous repair. Today, and despite a large number of preclinical data, no therapy capable of restoring the healthy structure and function of damaged articular cartilage is clinically available. Tissue-engineering strategies involving the combination of cells, scaffolding biomaterials and bioactive agents have been of interest notably for the repair of damaged articular cartilage. During the last 30 years, cartilage tissue engineering has evolved from the treatment of focal lesions of articular cartilage to the development of strategies targeting the osteoarthritis process. In this review, we focus on the different aspects of tissue engineering applied to cartilage engineering. We first discuss cells, biomaterials and biological or environmental factors instrumental to the development of cartilage tissue engineering, then review the potential development of cartilage engineering strategies targeting new emerging pathogenic mechanisms of osteoarthritis.

Revision surgery after third generation autologous chondrocyte implantation in the knee

PURPOSE

Third generation autologous chondrocyte implantation (ACI) is an established treatment for full thickness cartilage defects in the knee joint. However, little is known about cases when revision surgery is needed. The aim of the present study is to investigate the complication rates and the main reasons for revision surgery after third generation autologous chondrocyte implantation in the knee joint. It is of particular interest to examine in which cases revision surgery is needed and in which cases a "wait and see" strategy should be used.

METHODS

A total of 143 consecutive patients with 171 cartilage defects were included in this study with a minimum follow-up of two years. All defects were treated with third generation ACI (NOVACART®3D). Clinical evaluation was carried out after six months, followed by an annual evaluation using the International Knee Documentation Committee (IKDC) subjective score and the visual analogue scale (VAS) for rest and during activity. Revision surgery was documented.

RESULTS

The revision rate was 23.4 % (n = 36). The following major reasons for revision surgery were found in our study: symptomatic bone marrow edema (8.3 %, n = 3), arthrofibrosis (22.2 %, n = 8) and partial graft cartilage deficiency (47.2 %, n = 17). The following revision surgery was performed: retrograde drilling combined with Iloprost infusion therapy for bone marrow oedema (8.4 %, n = 3), arthroscopic arthrolysis of the suprapatellar recess (22.2 %, n = 8) and microfracturing/antegrade drilling (47.3 %, n = 17). Significant improvements of clinical scores after revision surgery were observed.

CONCLUSION

Revision surgery after third generation autologous chondrocyte implantation is common and is needed primarily in cases with arthrofibrosis, partial graft cartilage deficiency and symptomatic bone marrow oedema resulting in a significantly better clinical outcome.

Treatment of Full-Thickness Chondral Defects With Hyalograft C in the Knee: Long-term Results

BACKGROUND

Matrix-associated autologous chondrocyte transplantation (MACT) has become an established articular cartilage repair technique. It provides good short-term and midterm results; however, long-term results are lacking.

PURPOSE

To prospectively assess the clinical outcome after MACT in the knee to report long-term results.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Fifty-three subjects (females/males, 22/31; mean age, 32 ± 12 years) were treated between 2000 and 2006 with a hyaluronan-based MACT product and were followed prospectively. The mean body mass index (BMI) was 24.5 ± 3.8 kg/m(2) and the mean defect size was 4.4 ± 1.9 cm(2). Fifty patients had single defects and 3 had multiple defects (41 medial femoral condyle, 6 lateral femoral condyle, 2 patella, 1 tibia). Two patients had 2 defects (medial femoral condyle [MFC]/lateral femoral condyle and tibial/MFC), and in 1 case, multiple defects on the MFC were treated. The patients were stratified into 23 "simple," 22 "complex," and 8 "salvage" cases. Instability or malalignment was treated before or at the time of graft implantation. For 6 patients with small defects (<2 cm(2)), microfracturing was used as first-line treatment before MACT. Clinical assessment was performed once a year with the subjective and objective International Knee Documentation Committee (IKDC) scores, Lysholm score, and a modified Cincinnati Knee Rating System.

RESULTS

The mean follow-up time was 9.07 ± 2.9 years (range, 5-12 years). Treatment failure occurred in 12 of 53 cases (22.6%) an average of 2.99 ± 1.40 years after surgery. There was 1 failure (4.3%) among the simple cases, 4 failures (18.2%) in complex cases, and 7 failures (87.5%) in salvage cases. Statistically significant increases were observed in all scores at all time points compared with presurgery levels (P < .05). The subjective IKDC score improved from median 40.4 preoperatively to 74.7 at 10-year follow-up (n = 13 patients; P < .05).

CONCLUSION

MACT is an excellent surgical therapy for full-thickness cartilage defects of the knee, with good long-term results for simple defects. However, it should not be used in salvage cases.

Cartilage repair surgery: outcome evaluation by using noninvasive cartilage biomarkers based on quantitative MRI techniques?

BACKGROUND

New quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as outcome measures after cartilage repair.

OBJECTIVE

To review the current literature on the use of quantitative MRI biomarkers for evaluation of cartilage repair at the knee and ankle.

METHODS

Using PubMed literature research, studies on biochemical, quantitative MR imaging of cartilage repair were identified and reviewed.

RESULTS

Quantitative MR biomarkers detect early degeneration of articular cartilage, mainly represented by an increasing water content, collagen disruption, and proteoglycan loss. Recently, feasibility of biochemical MR imaging of cartilage repair tissue and surrounding cartilage was demonstrated. Ultrastructural properties of the tissue after different repair procedures resulted in differences in imaging characteristics. T2 mapping, T1rho mapping, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), and diffusion weighted imaging (DWI) are applicable on most clinical 1.5 T and 3 T MR scanners. Currently, a standard of reference is difficult to define and knowledge is limited concerning correlation of clinical and MR findings. The lack of histological correlations complicates the identification of the exact tissue composition.

CONCLUSIONS

A multimodal approach combining several quantitative MRI techniques in addition to morphological and clinical evaluation might be promising. Further investigations are required to demonstrate the potential for outcome evaluation after cartilage repair.

Influence of cryopreservation, cultivation time and patient's age on gene expression in Hyalograft® C cartilage transplants

PURPOSE

Our aim was to evaluate the impact of cryopreservation, cultivation time and patient's age on the expression of specific chondrogenic markers in Hyalograft® C transplants.

METHODS

Gene expression of chondrocyte markers [collagen type I (COL1A1), COL2A1, aggrecan, versican, melanoma inhibitory activity (MIA) and interleukin (IL)-1β] was analysed in cartilage biopsies (n = 17) and Hyalograft® C transplant samples (non-cryopreserved = 78, cryopreserved = 13) by quantitative real-time polymerase chain reaction (PCR). Correlation analyses were performed to evaluate the influence of the above-named parameters on the level of gene expression.

RESULTS

Cryopreservation of cells was found to decrease COL2A1 and MIA significantly (4.6-fold, p < 0.01 and 2-fold, p < 0.045, respectively). The duration of cryopreservation had no further influence on the expression of these factors. No correlation was detected between cultivation time (75 ± 31 days) and the expression level of any gene. Cartilage transplants from older patients (>35 years) exhibited a significantly higher IL-1β expression (3.7-fold, p < 0.039) than transplants from younger patients (≤ 35 years).

CONCLUSIONS

Our data demonstrate that cryopreservation has a profound impact on chondrocyte metabolic activity by decreasing the expression of COL2A1 and MIA in Hyalograft® C transplants, independent of the duration of cryopreservation.