Arthroscopic treatment of osteochondral knee defects with resorbable biphasic synthetic scaffold: clinical and radiological results and long-term survival analysis

Functional performance of a bi-layered chitosan-nano-hydroxyapatite osteochondral scaffold: a pre-clinical in vitro tribological study

Osteochondral grafts are used for repair of focal osteochondral lesions. Autologous grafts are the gold standard treatment; however, limited graft availability and donor site morbidity restrict use. Therefore, there is a clinical need for different graft sources/materials which replicate natural cartilage function. Chitosan has been proposed for this application. The aim of this study was to assess the biomechanics and biotribology of a bioresorbable chitosan/chitosan-nano-hydroxyapatite osteochondral construct (OCC), implanted in an in vitro porcine knee experimental simulation model. The OCC implanted in different surgical positions (flush, proud and inverted) was compared to predicate grafts in current clinical use and a positive control consisting of a stainless steel graft implanted proud of the cartilage surface. After 3 h (10 800 cycles) wear simulation under a walking gait, subsidence occurred in all OCC samples irrespective of surgical positioning, but with no apparent loss of material and low meniscus wear. Half the predicate grafts exhibited delamination and scratching of the cartilage surfaces. No graft subsidence occurred in the positive controls but wear and deformation of the meniscus were apparent. Implanting a new chitosan-based OCC either optimally (flush), inverted or proud of the cartilage surface resulted in minimal wear, damage and deformation of the meniscus.

Biomimetic biphasic scaffolds in osteochondral tissue engineering: Their composition, structure and consequences

Approaches to the design and construction of biomimetic scaffolds for osteochondral tissue, show increasing advances. Considering the limitations of this tissue in terms of repair and regeneration, there is a need to develop appropriately designed scaffolds. A combination of biodegradable polymers especially natural polymers and bioactive ceramics, shows promise in this field. Due to the complicated architecture of this tissue, biphasic and multiphasic scaffolds containing two or more different layers, could mimic the physiology and function of this tissue with a higher degree of similarity. The purpose of this review article is to discuss the approaches focused on the application of biphasic scaffolds for osteochondral tissue engineering, common methods of combining layers and the ultimate consequences of their use in patients were discussed.

Within or Without You? A Perspective Comparing In Situ and Ex Situ Tissue Engineering Strategies for Articular Cartilage Repair

Human articular cartilage has a poor ability to self-repair, meaning small injuries often lead to osteoarthritis, a painful and debilitating condition which is a major contributor to the global burden of disease. Existing clinical strategies generally do not regenerate hyaline type cartilage, motivating research toward tissue engineering solutions. Prospective cartilage tissue engineering therapies can be placed into two broad categories: i) Ex situ strategies, where cartilage tissue constructs are engineered in the lab prior to implantation and ii) in situ strategies, where cells and/or a bioscaffold are delivered to the defect site to stimulate chondral repair directly. While commonalities exist between these two approaches, the core point of distinction-whether chondrogenesis primarily occurs "within" or "without" (outside) the body-can dictate many aspects of the treatment. This difference influences decisions around cell selection, the biomaterials formulation and the surgical implantation procedure, the processes of tissue integration and maturation, as well as, the prospects for regulatory clearance and clinical translation. Here, ex situ and in situ cartilage engineering strategies are compared: Highlighting their respective challenges, opportunities, and prospects on their translational pathways toward long term human cartilage repair.

Articular cartilage delamination at eight years following cellular-based repair procedures: a case reports

This report describes two cases of late cartilage delamination in two young adults after two different autologous cell-based techniques for cartilage restoration: 1. Matrix-assisted autologous chondrocyte implantation (MACI) and 2. Hyaluronic acid-bone marrow aspirate concentrate (HA-BMAC). Both cases demonstrate that even in patients who do not present with any ongoing symptoms after primary surgery, a cellular-based graft's subsequent delamination can occur later. It is possible that regardless of the technique used or the time passed since the surgery, a graft failure may occur at some level, causing delamination of a previously asymptomatic cartilage restoration graft and a traumatic event with long-term follow-up. Surgeons must be alert to this injury and describe histologic findings to determine where failure occurs.

Synthetic Biphasic Scaffolds versus Microfracture for Articular Cartilage Defects of the Knee: A Retrospective Comparative Study

OBJECTIVE

The purpose of this study was to compare the results of a biphasic synthetic scaffold (TruFit, Smith & Nephew) to microfracture for the treatment of knee cartilage defects and identify patient- and lesion-specific factors that influence outcomes.

DESIGN

Prospectively collected data from 132 patients (mean age, 41.8 years; 69% male) with isolated chondral or osteochondral femoral defects treated with biphasic synthetic scaffolds (n = 66) or microfracture (n = 66) were reviewed. Clinical outcomes were evaluated longitudinally over 5 years with the Short Form-36 (SF-36), Activities of Daily Living of the Knee Outcome Survey (KOS-ADL), International Knee Documentation Committee (IKDC), and Marx Activity Scale. Cartilage-sensitive magnetic resonance imaging (MRI) was performed to evaluate osseous integration and cartilage fill in a subgroup of patients. Multivariate regression analysis was used to identify predictors of clinical outcomes within the scaffold group.

RESULTS

Both groups demonstrated clinically significant improvements in knee clinical scores over 5 years (P < 0.01). There were no significant differences in KOS-ADL and IKDC scores between groups up to 5 years postoperatively. Marx activity level scores in the microfracture group declined over time, while significant improvements in activity level scores were observed in the scaffold group over 5 years (P < 0.01). Good-quality tissue fill and cartilage isointensity were more often observed in the scaffold group compared with the microfracture group, particularly with longer time intervals. Increasing age, high body mass index, prior microfracture, and traumatic etiology were predictors for inferior outcomes in the scaffold group.

CONCLUSIONS

Activity level and MRI appearance following treatment of cartilage lesions with the biphasic synthetic scaffold were superior to microfracture over time in this nonrandomized, retrospective comparison.

Cell-free osteochondral scaffolds provide a substantial clinical benefit in the treatment of osteochondral defects at a minimum follow-up of 5 years

Purpose

The treatment of osteochondral lesions is challenging and no consensus has been established about the best option for restoring both cartilage and subchondral bone. Multilayer collagen-hydroxyapatite scaffolds have shown promising clinical results, but the outcome at a follow-up longer than 5 years still has to be proved. The aim was to evaluate the clinical outcome of patients with a knee isolated osteochondral lesion treated with a biomimetic three-layered scaffold at a minimum 5 years of follow-up.

Methods

Twenty-nine patients (23 males and 6 females, mean age 31.5 ± 11.4 years) were evaluated retrospectively before surgery, at 1 and 2 years and at last follow-up (FU). Visual Analog Scale (VAS) for pain, International Knee Documentation Committee (IKDC) Subjective Score, Tegner-Lysholm Knee Scoring Scale and Tegner Activity Level Scale were collected. Mean FU was 7.8 ± 2.0 years (min 5.1 - max 11.3). The etiology of the defect was Osteochondritis Dissecans or osteonecrosis (17 vs 12 cases).

Results

At 12 months FU the IKDC score improved from 51.1 ± 21.7 to 80.1 ± 17.9 (p < 0.01), Tegner Lysholm Score from 59.9 ± 17.3 to 92.5 ± 9.0 (p < 0.01), VAS from 6.1 ± 2.1 to 1.7 ± 2.3 (p < 0.01) and Tegner Activity Level Scale from 1.6 ± 0.5 to 4.9 ± 1.7 (p < 0.01). The results remained stable at 24 months, while at last FU a statistically significant decrease in IKDC, Tegner Lysholm and Tegner Activity Scale was recorded, though not clinically relevant. Patients under 35 achieved statistically better outcomes.

Conclusions

The use of a cell-free collagen-hydroxyapatite osteochondral scaffold provides substantial clinical benefits in the treatment of knee osteochondral lesions at a minimum follow-up of 5 years, especially in patients younger than 35 years.

Level of evidence

Level IV.

Multi-layer cell-free scaffolds for osteochondral defects of the knee: a systematic review and meta-analysis of clinical evidence

Purpose

The aim of this study was to analyze the clinical results provided by multi-layer cell-free scaffolds for the treatment of knee osteochondral defects.

Methods

A systematic review was performed on PubMed, Web of Science, and Cochrane to identify studies evaluating the clinical efficacy of cell-free osteochondral scaffolds for knee lesions. A meta-analysis was performed on articles reporting results of the International Knee Documentation Committee (IKDC) and Tegner scores. The scores were analyzed as improvement from baseline to 1, 2, and ≥ 3 years of follow-up. The modified Coleman Methodology Score was used to assess the study methodology.

Results

A total of 34 studies (1022 patients) with a mean follow-up of 35 months was included. Only three osteochondral scaffolds have been investigated in clinical trials: while TruFit® has been withdrawn from the market for the questionable results, the analysis of MaioRegen and Agili-C™ provided clinical improvements at 1, 2, and ≥ 3 years of follow-up (all significantly higher than the baseline, p < 0.05), although with a limited recovery of the sport-activity level. A low rate of adverse events and an overall failure rate of 7.0% were observed, but the overall evidence level of the available studies is limited.

Conclusions

Multi-layer scaffolds may provide clinical benefits for the treatment of knee osteochondral lesions at short- and mid-term follow-up and with a low number of failures, although the sport-activity level obtained seems to be limited. Further research with high-level studies is needed to confirm the role of multi-layer scaffold for the treatment of knee osteochondral lesions.

Autologous adipose stem cell therapy for knee osteoarthritis: where are we now?

Introduction: The purpose of this study was to evaluate the efficacy and safety of adipose-derived stem cell (ADSC) or stromal vascular fraction (SVF) injections for knee osteoarthritis (OA) treatment by analyzing all randomized controlled trials dealing with this topic. Materials and methods: The following search terms were used in PUBMED, EMBASE, Scopus, and the Cochrane Library Database on 14 November 2019: 'adipose derived stem cell' OR 'stromal vascular fraction' OR 'SVF' OR 'multipotent mesenchymal stromal cells' OR 'stem cell' OR 'derived stem cell' OR 'autologous' AND 'knee' OR 'osteoarthritis' OR 'chondral defect' OR 'randomized' OR 'controlled trial.' No time limit was given to publication date. We included randomized controlled trials (RCTs) based on the following criteria: (1) English studies; (2) patient population diagnosed with knee OA and treated with ADSCs or SVF injections; (3) comparison group treated with placebo, surgery, or adjuvant injections, such as platelet rich-plasma or hyaluronic acid. Results: Intra-articular injections of adipose stem cell therapy in the form of ADSC or SVF is a safe procedure for the treatment of knee OA, with good clinical and radiological outcomes in the early follow-up period (12-24 months). In addition, treatment with fat-derived cells showed a very low complication rate (16.15%) of which all were considered to be minor. Conclusions: ADSCs and SVF seem to produce promising good to excellent clinical results for the treatment of knee OA. However, the length and modalities of follow-up in the different conditions are extremely variable. Nevertheless, it appears that the use of adipose-derived stem cells is associated with clinical and radiological improvements and minimal complication rates. To avoid bias deriving from the use of biological adjuvants or surgical procedures, randomized controlled trials comparing ADSCs or SVF and other treatments (for example, platelet rich-plasma or hyaluronic acid injections) should be performed.

Treatment of focal chondral lesions in the knee using a synthetic scaffold plug: Long-term clinical and radiological results

The management of symptomatic articular cartilage lesions, especially in the young, fit individual remains an area of considerable controversy. Articular cartilage repair or reconstruction techniques may offer these patients alternatives to arthroplasty. The TruFit™ plug is a synthetic biphasic polymer scaffold that is designed for implantation at the site of a focal chondral defect. The aim of this study is to report the long-term clinical and radiological outcomes of patients treated with the TruFit™ plug for chondral defects within the knee. 11 patients underwent TruFit™ plug implantation. Long-term outcome scores were available for 6 patients at a mean follow up of 121 months (SD 12.0 months, 1 patient unavailable and 4 excluded after arthroplasty surgery). There was no statistically significant improvements in any score although all scores did improve. At a mean radiographic follow up of 70 months (17-113) of 9 patients, the mean MOCART score was 22.2 (SD 15.6). All patients had incomplete or no evidence of plug incorporation and persistent chondral loss. Based on these results, we do not recommend the use of the TruFit™ plug.

MaioRegen Osteochondral Substitute for the Treatment of Knee Defects: A Systematic Review of the Literature

BACKGROUND

This study aims to investigate the clinical and radiological efficacy of three-dimensional acellular scaffolds (MaioRegen) in restoring osteochondral knee defects.

METHODS

MEDLINE, Scopus, CINAHL, Embase, and Cochrane Databases were searched for articles in which patients were treated with MaioRegen for osteochondral knee defects.

RESULTS

A total of 471 patients were included in the study (mean age 34.07 ± 5.28 years). The treatment involved 500 lesions divided as follows: 202 (40.4%) medial femoral condyles, 107 (21.4%) lateral femoral condyles, 28 (5.6%) tibial plateaus, 46 (9.2%) trochleas, 74 (14.8%) patellas, and 43 (8.6%) unspecified femoral condyles. Mean lesion size was 3.6 ± 0.85 cm². Only four studies reported a follow-up longer than 24 months. Significant clinical improvement has been reported in almost all studies with further improvement up to 5 years after surgery. A total of 59 complications were reported of which 52 (11.1%) experienced minor complications and 7 (1.48%) major complications. A total of 16 (3.39%) failures were reported.

CONCLUSION

This systematic review describes the current available evidence for the treatment of osteochondral knee defects with MaioRegen Osteochondral substitute reporting promising satisfactory and reliable results at mid-term follow-up. A low rate of complications and failure was reported, confirming the safety of this scaffold. Considering the low level of evidence of the study included in the review, this data does not support the superiority of the Maioregen in terms of clinical improvement at follow-up compared to conservative treatment or other cartilage techniques.

Emerging therapies for cartilage regeneration in currently excluded 'red knee' populations

The field of articular cartilage repair has made significant advances in recent decades; yet current therapies are generally not evaluated or tested, at the time of pivotal trial, in patients with a variety of common comorbidities. To that end, we systematically reviewed cartilage repair clinical trials to identify common exclusion criteria and reviewed the literature to identify emerging regenerative approaches that are poised to overcome these current exclusion criteria. The term “knee cartilage repair” was searched on clinicaltrials.gov. Of the 60 trials identified on initial search, 33 were further examined to extract exclusion criteria. Criteria excluded by more than half of the trials were identified in order to focus discussion on emerging regenerative strategies that might address these concerns. These criteria included age (<18 or >55 years old), small defects (<1 cm²), large defects (>8 cm²), multiple defect (>2 lesions), BMI >35, meniscectomy (>50%), bilateral knee pathology, ligamentous instability, arthritis, malalignment, prior repair, kissing lesions, neurologic disease of lower extremities, inflammation, infection, endocrine or metabolic disease, drug or alcohol abuse, pregnancy, and history of cancer. Finally, we describe emerging tissue engineering and regenerative approaches that might foster cartilage repair in these challenging environments. The identified criteria exclude a majority of the affected population from treatment, and thus greater focus must be placed on these emerging cartilage regeneration techniques to treat patients with the challenging “red knee”.