Factors Influencing the Results in Matrix-Associated Autologous Chondrocyte Implantation: A 2 - 5 Year Follow-Up Study

Lower cell number, lateral defect location and milder grade are associated with improved autologous chondrocyte implantation outcome

PURPOSE

To investigate patient demographic, injury and surgery/treatment-associated factors that can influence the patient-reported outcome (Lysholm score), following autologous chondrocyte implantation (ACI) in a large, 'real-world', nonuniform, prospective data examined retrospectively.

METHODS

Knee patients treated at the Robert Jones and Agnes Hunt Orthopaedic Hospital, UK, using ACI between 1996 and 2020 were eligible. All longitudinal postoperative Lysholm scores collected between 1 and 23 years after ACI treatment and before any second major procedure (e.g., arthroplasty) were included. Multilevel longitudinal models were built investigating the association of short-term (1 year) or long-term trends in Lysholm score with baseline demographic, clinical and cell-culture variables, namely age, gender, smoker status, body mass index, baseline Lysholm score, time from surgery, defect grade, diameter and location, number of defects, previous microfracture, patch/scaffold type, associated procedure(s), number of cells implanted and their passage number.

RESULTS

Following filtering, 306 of the 427 knee ACI procedures reviewed were suitable for inclusion. Factors shown to result in higher postoperative Lysholm scores in the short term were lower patient age, higher baseline Lysholm scores, fewer implanted cells and a lateral femoral defect location. The factor which was associated with higher long-term postoperative Lysholm scores was a milder defect grade. Additionally, the failure rate in this cohort was explored and it was found that 73/306 (24%) of patients experienced joint failure according to our definition. Furthermore, the outcome was not influenced by coincidental procedures in this cohort of patients.

CONCLUSIONS

This study has identified a number of baseline factors associated with patient-reported outcomes following ACI and shows that treatment of associated pathology at the time of surgery potentially restores patient outcomes to a similar level as those with no associated pathologies.

LEVEL OF EVIDENCE

Level IV.

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

Short term clinical outcomes of a Prochondrix® thin laser-etched osteochondral allograft for the treatment of articular cartilage defects in the knee

Objective: The purpose of this study is to evaluate the short-term clinical outcomes of Prochondrix® novel thin, laser-etched osteochondral allograft on isolated articular cartilage defects. Methods: Eighteen patients with isolated, symptomatic, full-thickness articular cartilage lesions were treated with marrow stimulation followed by placement of a T-LE allograft. Demographic and intra-operative data was recorded as well as pre- and post-operative International Knee Documentation Committee (IKDC), Short Form-36 (SF-36), Knee Injury and Osteoarthritis Outcome Score (KOOS), Visual Analogue Scale (VAS) and Tegner scores. Pre- and post-operative data was compared at 6, 12, 24 and 36 months post operatively. Failures requiring reoperation were also recorded. Results: At a mean follow-up of 2.5 years (6-43 months), VAS decreased from 6.55 to 2.55 (p = .02) and subjective IKDC scores increased from 37.61 to 59.65 (p = .02). Statistically significant increases were also seen in KOOS Function-Sports and Recreational Activities (+26.04, p = .04) and KOOS QOL (+18.76, p = .007) as well as in SF-36 Physical Functioning (+25.20, p = .04), Energy/Fatigue (+16.50, p = .02), Social Functioning (+11.79, p = .04), and Bodily Pain (+25.18, p = .04). There were two failures requiring reoperation: one conversion to a patellofemoral arthroplasty (PFA), and one graft dislodgement which required removal. Conclusion: Treatment of articular cartilage lesions of the knee with ProChondrix® has demonstrated sustained positive results out to a mean follow-up of two and a half years in this prospective case series with a low failure rate that required reoperation (2 patients) in this series. These results are comparable to the short-term results of other cartilage restoration procedures currently in use today. A meta-analysis of osteochondral allografting demonstrated a mean 86.7% survival rate at 5 years with significant improvements in clinical outcome scores reaching MCID values.

The Predictive Value of Early Postoperative MRI-Based Bone Marrow Parameters for Mid-Term Outcome after MACI with Autologous Bone Grafting at the Knee

OBJECTIVE

The aim of this study was to longitudinally determine the prognostic value of early postoperative quantitative 3T-MRI (magnetic resonance imaging) parameters of subchondral bone marrow for 2-year clinical and MRI outcome after matrix-associated autologous chondrocyte implantation (MACI) with autologous bone grafting (ABG) at the knee.

DESIGN

Consecutive subjects who received MACI with ABG for treatment of focal osteochondral defects received MRI follow-up 3, 6, 12, and 24 months postoperatively. Quantitative MRI included bone marrow edema-like lesion (BMEL) volume measurements and single-voxel magnetic resonance spectroscopy (MRS; n = 9) of the subchondral bone marrow. At 2-year follow-up, morphological MRI outcome included MOCART (magnetic resonance observation of cartilage repair tissue) 2.0 scores. Clinical outcomes were assessed using Lysholm scores.

RESULTS

Among a total of 18 subjects (mean age: 28.7 ± 8.4 years, n = 14 males) with defects at the medial or lateral (n = 15 and n = 3, respectively) condyle, mean BMEL volume decreased from 4.9 cm³ at 3 months to 2.0 cm³ at 2-year follow-up (P = 0.040). MRS-based bone marrow water T2 showed a decrease from 20.7 ms at 1-year follow-up to 16.8 ms at 2-year follow-up (P = 0.040). Higher BMEL volume at 6 months correlated with lower 2-year Lysholm (R = -0.616, P = 0.015) and MOCART 2.0 scores (R = -0.567, P = 0.027). Larger early postoperative BMEL volumes at 3 months (R = -0.850, P = 0.007) and 6 months (R = -0.811, P = 0.008) correlated with lower MRS-based unsaturated lipid fractions at 2-year follow-up. Furthermore, patients with early postoperative bony defects showed worse MOCART 2.0 (P = 0.044) and Lysholm scores (P = 0.017) after 24 months.

CONCLUSION

Low subchondral BMEL volume and optimal restoration of the subchondral bone at early postoperative time points predict better 2-year clinical and MRI outcomes after MACI with ABG.

Freeze-Dried Curdlan/Whey Protein Isolate-Based Biomaterial as Promising Scaffold for Matrix-Associated Autologous Chondrocyte Transplantation-A Pilot In-Vitro Study

The purpose of this pilot study was to establish whether a novel freeze-dried curdlan/whey protein isolate-based biomaterial may be taken into consideration as a potential scaffold for matrix-associated autologous chondrocyte transplantation. For this reason, this biomaterial was initially characterized by the visualization of its micro- and macrostructures as well as evaluation of its mechanical stability, and its ability to undergo enzymatic degradation in vitro. Subsequently, the cytocompatibility of the biomaterial towards human chondrocytes (isolated from an orthopaedic patient) was assessed. It was demonstrated that the novel freeze-dried curdlan/whey protein isolate-based biomaterial possessed a porous structure and a Young's modulus close to those of the superficial and middle zones of cartilage. It also exhibited controllable degradability in collagenase II solution over nine weeks. Most importantly, this biomaterial supported the viability and proliferation of human chondrocytes, which maintained their characteristic phenotype. Moreover, quantitative reverse transcription PCR analysis and confocal microscope observations revealed that the biomaterial may protect chondrocytes from dedifferentiation towards fibroblast-like cells during 12-day culture. Thus, in conclusion, this pilot study demonstrated that novel freeze-dried curdlan/whey protein isolate-based biomaterial may be considered as a potential scaffold for matrix-associated autologous chondrocyte transplantation.

Crosstalk Between Mesenchymal Stromal Cells and Chondrocytes: The Hidden Therapeutic Potential for Cartilage Regeneration

Cartilage injuries following trauma create a puzzling clinical scenario. The finite reparative potential of articular cartilage is well known, and injuries are associated with an increased risk of osteoarthritis. Cell-based therapies have spotlighted chondrocytes and mesenchymal stromal cells (MSCs) as the functional unit of articular cartilage and the progenitor cells, respectively. The available clinical treatments cannot reproduce the biomechanical properties of articular cartilage and call for continuous investigations into alternative approaches. Co-cultures of chondrocytes and MSCs are an attractive in vitro system to step closer to the in vivo multicellular environment's complexity. Research on the mechanisms of interaction between both cell types will reveal essential cues to understand cartilage regeneration. This review describes the latest discoveries on these interactions, along with advantages and main challenges in vitro and in vivo. The successful clinical translation of in vitro studies requires establishing rigorous standards and clinically relevant research models and an organ-targeting therapeutic strategy.

Studies of Articular Cartilage Repair from 2009 to 2018: A Bibliometric Analysis of Articles

Objective

To perform a bibliometric analysis of research on articular cartilage repair published in Chinese and English over the past decade. Fundamental and clinical research topics of high interest were further comparatively analyzed.

Methods

Relevant studies published from 1 January 2009 to 31 December 2018 (10 years) were retrieved from the Wanfang database (Chinese articles) and six databases, including MEDLINE, WOS, INSPEC, SCIELO, KJD, and RSCI on the website “Web of Science” (English articles), using key words: “articular cartilage” AND “injury” AND “repair”. The articles were categorized according to research focuses for a comparative analysis between those published in Chinese vs English, and further grouped according to publication date (before and after 2014). A comparative analysis was performed on research focus to characterize the variation in research trends between two 5‐year time spans. Moreover, articles were classified as basic and clinical research studies.

Results

Overall, 5762 articles were retrieved, including 2748 in domestic Chinese journals and 3014 in international English journals. A total of 4937 articles focused on the top 10 research topics, with the top 3 being stem cells (32.1%), tissue‐engineered scaffold (22.8%), and molecular mechanisms (16.4%). Differences between the numbers of Chinese and English papers were observed for 3 topics: chondrocyte implantation (104 vs 316), osteochondral allograft (27 vs 86), and microfracture (127 vs 293). The following topics gained more research interest in the second 5‐year time span compared with the first: microfracture, osteochondral allograft, osteochondral autograft, stem cells, and tissue‐engineered scaffold. Articles with a focus on three‐dimensional‐printing technology have shown the fastest increase in publication numbers. Among 5613 research articles, basic research studies accounted for the majority (4429), with clinical studies described in only 1184 articles. The top 7 research topics of clinical studies were: chondrocyte implantation (28.7%), stem cells (21.9%), microfracture (19.2%), tissue scaffold (10.6%), osteochondral autograft (10.5%), osteochondral allograft (6.3%), and periosteal transplantation (2.8%).

Conclusion

Studies focused on stem cells and tissue‐engineered scaffolds led the field of damaged articular cartilage repair. International researchers studied allograft‐related implantation approaches more often than Chinese researchers. Traditional surgical techniques, such as microfracture and osteochondral transplantation, gained high research interest over the past decade.