Biologic principles of minced cartilage implantation: a narrative review

Arthroscopic Autologous Minced Cartilage Implantation of Cartilage Defects in the Knee: A 2-Year Follow-up of 62 Patients

Background

Symptomatic cartilage defects of the knee joint are frequently diagnosed and can be treated with different available surgical methods. Nevertheless, there is currently no gold standard treatment for all indications. Minced cartilage implantation is increasingly coming into focus as a refined surgical technique.

Purpose

To investigate the 2-year clinical and radiological outcomes of arthroscopic autologous minced cartilage repair with the standardized commercial implantation system AutoCart.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 62 consecutive patients were included and prospectively evaluated preoperatively and at 3, 6, 12, and 24 months postoperatively. Outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Single Assessment Numeric Evaluation (SANE), and Tegner activity scale at all follow-up time points. The examination of preoperative magnetic resonance imaging (MRI) was performed using the Area Measurement and Depth and Underlying Structures (AMADEUS) score, and the examination of MRI at 24 months was performed using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 score.

Results

There were 34 male and 28 female patients (mean age, 38.79 ± 10.78 years) with symptomatic cartilage lesions with a mean defect size of 2.53 ± 1.24 cm2. Lesions were predominantly International Cartilage Repair Society grade 3 located in the region of the femoral condyles. Concomitant surgery was performed in 40.3% of patients. The total KOOS score significantly improved from 62.4 ± 13.1 at baseline to 74.4 ± 15.9 at 24 months (P < .001). The secondary outcome measures of the VAS, WOMAC, and SANE showed a similar pattern, with score improvements in the follow-up period compared to baseline. The mean AMADEUS score was 64.75 ± 13.87, while the mean MOCART 2.0 score was 62.88 ± 9.86, among 20 available patients. The revision surgery rate was 8.1% mainly because of hypertrophy (6.5%).

Conclusion

Among this cohort of patients, minced cartilage implantation demonstrated satisfying 2-year outcomes with increased patient-reported outcome measure scores from 3 to 24 months postoperatively. Regenerated tissue quality on MRI was comparable to that using other cartilage repair methods and showed no associations with patient characteristics or patient-reported outcome measures. Larger cohorts, longer postoperative intervals, and comparable trials are needed to further evaluate the role of this technique in treating cartilage defects.

Autologous matrix-induced chondrogenesis provides better outcomes in comparison to autologous minced cartilage implantation in the repair of knee chondral defects

PURPOSE

In symptomatic mid-sized focal chondral defects, autologous matrix-induced chondrogenesis (AMIC) and minced cartilage implantation (MCI) offer two versatile treatment options. This study aimed to conduct a matched-patient analysis of patient-reported outcome measures to compare these two surgical treatment methods for focal chondral defects.

METHODS

At the first centre, patients underwent a single-stage procedure in which autologous cartilage was hand-minced, implanted into the defect and fixed with fibrin glue. At the second centre, patients underwent AMIC, which was fixed in place with fibrin glue. All patients were seen 2-4 years postoperatively. Postoperative outcomes were assessed using the visual analogue scale for pain (VAS), the Lysholm score and the five domains of the knee osteoarthritis outcome score (KOOS). Patients from each surgical centre were matched by age, sex, defect size and defect localisation.

RESULTS

In total, 48 patients from two surgical centres (24 from each site) were matched for sex, age (MCI 30.3 ± 14.9 years vs. AMIC 30.8 ± 13.7 years) and defect size (MCI 2.49 ± 1.5 cm2 vs. AMIC 2.65 ± 1.1 cm2). Significantly better scores in the AMIC cohort were noted for VAS (p = 0.004), Lysholm (p = 0.043) and the KOOS subscales for pain (p = 0.016) and quality of life (p = 0.036). There was a significantly greater proportion of positive responders for Lysholm in the AMIC group (92%) compared with the MCI group (64%).

CONCLUSIONS

The AMIC procedure delivers superior patient outcomes compared with hand-minced autologous cartilage implantation. These are mid-term outcomes, with follow-up between 2 and 4 years.

LEVEL OF EVIDENCE

Level III.

Autologous platelet-rich plasma and fibrin-augmented minced cartilage implantation in chondral lesions of the knee leads to good clinical and radiological outcomes after more than 12 months: A retrospective cohort study of 71 patients

Purpose

The treatment of cartilage lesions remains a challenge. Matrix-associated autologous chondrocyte implantation has evolved to become the gold standard procedure. However, this two-step procedure has crucial disadvantages, and the one-step minced cartilage procedure has gained attention. This retrospective study aimed to evaluate the clinical and radiological outcome of an all-autologous minced cartilage technique in cartilage lesions at the knee joint.

Methods

In this retrospective cohort study, 71 patients (38.6 years ± 12.0, 39,4% female) with a magnetic resonance imaging (MRI) confirmed grade III-IV cartilage defect at the medial femur condyle (n = 20), lateral femur condyle (n = 2), lateral tibia plateau (n = 1), retropatellar (n = 28) and at the trochlea (n = 20) were included. All patients were treated with an all-autologous minced cartilage procedure (AutoCart™). Clinical knee function was evaluated by the Tegner score, visual analogue scale, the subjective and objective evaluation form of the International Knee Documentation Committee and the Knee Injury and Osteoarthritis Outcome Score (KOOS). MRI analyses were performed by magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 knee score. Follow-up examination was 13.7 ± 4.2 (12-24) months postoperative.

Results

All clinical scores significantly improved after surgical intervention (p < 0.0001), especially the subgroup sports and recreation of KOOS showed clear changes from baseline in the follow-up examination. In the postoperative MRI evaluation, 39 of 71 patients showed a complete fill of the cartilage defect without subchondral changes in 78% of the patients in the MOCART 2.0 score in the follow-up analysis. None of the patients showed adverse effects, which are linked to the minced cartilage procedure during the time of follow-up.

Conclusion

An all-autologous minced cartilage technique for chondral lesions at the knee joint seems to be an effective and safe treatment method with good clinical and radiological short-term results.

Level of Evidence

Level IV.

Influence of cartilage defects and a collagen gel on integrity of corresponding intact cartilage: a biomechanical in-vitro study

INTRODUCTION

Numerous cartilage repair procedures have been developed for focal lesions to minimize suffering and possibly prevent the development of osteoarthritis with a focus on so-called one-step procedures. The aim of this work was to investigate the effects of both focal cartilage defects and a biomaterial (ChondroFiller) on the corresponding articular cartilage.

MATERIALS AND METHODS

On a friction test stand, 18 porcine osteochondral cylinders were tested in six experimental setups under cyclic loading (33 N) against a friction partner in saline solution. The friction partner (cartilage, bone, cartilage defect, cartilage defect with ChondroFiller) and the running times (1 hour and 6 hours) were varied. The damage to the osteochondral cylinders was assessed histologically using a visual damage classification.

RESULTS

The cartilage versus bone group showed severe cartilage damage in both the one-hour and six-hour experiments, with an average damage score of 3.5. Damage in the cartilage versus cartilage defect group was moderate, with damage values of 2.5 (1 h) and 2.67 (6 h). The cartilage versus cartilage defect with ChondroFiller group showed a damage value of 2.67 for the one-hour and 2.5 for the six-hour trials.

CONCLUSIONS

Even focal grade IV cartilage lesions can lead to significant damage to the corresponding cartilage in vitro. The damage could not be reduced by the use of ChondroFiller, likely because of the initial instability of this biomaterial. Therefore, a biomaterial must be stable in the beginning with regard to full weight-bearing, or joint loading should be delayed until stable filling of the defect is achieved.

Fresh osteochondral allograft transplantation for knee full-thickness articular cartilage lesions using femoral head of living donors: short-term results

BACKGROUND

Fresh osteochondral allograft transplantation is a good treatment option of cartilage defects. However, this treatment option is not available in all countries due to limited graft availability and tissue banks limitations. The purpose of this study is to assess the short term functional and imaging outcomes of fresh osteochondral allograft transplantation in the knee using the femoral head of living donors.

HYPOTHESIS

Fresh osteochondral allografts from the femoral heads of living donors is a valid graft source for management of distal Femur cartilage defects. This technique can improve functional knee scores with good radiological outcomes.

STUDY DESIGN

Prospective case series.

METHODS

Fifteen patients with full thickness cartilage defects of the distal femur underwent osteochondral allograft transplantation from the femoral heads of living donors. Grafts were transplanted by both shell and multiple dowels techniques. The average follow up duration was 18.3 months (range, 12-25 months). Patients were evaluated by Lysholm and International Knee Documentation Committee (IKDC) scores, radiography and MR imaging using Osteochondral Allograft MRI Scoring System (OCAMRISS).

RESULTS

There was a statistically significant improvement (P < 0.001) in both Lysholm and IKDC average scores at 6 months and 12 months postoperative. Postoperative MRI was done at an average 6.8 months (range, 5-11 months) postoperative. The mean total OCAMRISS score was 3.4 (range, 1-7). A second look arthroscopy was done in four patients and showed intact articular cartilage in all three patients.

CONCLUSION

Femoral head of living donors is a valid new source for fresh osteochondral allograft transplantation of knee osteochondral lesions. Short term results showed improvement in clinical assessment scores. Follow up imaging showed graft incorporation and good MRI scores.

Wet 3D printing of biodegradable porous scaffolds to enable room-temperature deposition modeling of polymeric solutions for regeneration of articular cartilage

Tissue engineering has emerged as an advanced strategy to regenerate various tissues using different raw materials, and thus it is desired to develop more approaches to fabricate tissue engineering scaffolds to fit specific yet very useful raw materials such as biodegradable aliphatic polyester like poly (lactide-co-glycolide) (PLGA). Herein, a technique of 'wet 3D printing' was developed based on a pneumatic extrusion three-dimensional (3D) printer after we introduced a solidification bath into a 3D printing system to fabricate porous scaffolds. The room-temperature deposition modeling of polymeric solutions enabled by our wet 3D printing method is particularly meaningful for aliphatic polyester, which otherwise degrades at high temperature in classic fuse deposition modeling. As demonstration, we fabricated a bilayered porous scaffold consisted of PLGA and its mixture with hydroxyapatite for regeneration of articular cartilage and subchondral bone. Long-termin vitroandin vivodegradation tests of the scaffolds were carried out up to 36 weeks, which support the three-stage degradation process of the polyester porous scaffold and suggest faster degradationin vivothanin vitro. Animal experiments in a rabbit model of articular cartilage injury were conducted. The efficacy of the scaffolds in cartilage regeneration was verified through histological analysis, micro-computed tomography (CT) and biomechanical tests, and the influence of scaffold structures (bilayerversussingle layer) onin vivotissue regeneration was examined. This study has illustrated that the wet 3D printing is an alternative approach to biofabricate tissue engineering porous scaffolds based on biodegradable polymers.

Regulation of Oxygen Tension as a Strategy to Control Chondrocytic Phenotype for Cartilage Tissue Engineering and Regeneration

Cartilage defects and osteoarthritis are health problems which are major burdens on health care systems globally, especially in aging populations. Cartilage is a vulnerable tissue, which generally faces a progressive degenerative process when injured. This makes it the 11th most common cause of global disability. Conservative methods are used to treat the initial phases of the illness, while orthopedic management is the method used for more progressed phases. These include, for instance, arthroscopic shaving, microfracturing and mosaicplasty, and joint replacement as the final treatment. Cell-based implantation methods have also been developed. Despite reports of successful treatments, they often suffer from the non-optimal nature of chondrocyte phenotype in the repair tissue. Thus, improved strategies to control the phenotype of the regenerating cells are needed. Avascular tissue cartilage relies on diffusion for nutrients acquisition and the removal of metabolic waste products. A low oxygen content is also present in cartilage, and the chondrocytes are, in fact, well adapted to it. Therefore, this raises an idea that the regulation of oxygen tension could be a strategy to control the chondrocyte phenotype expression, important in cartilage tissue for regenerative purposes. This narrative review discusses the aspects related to oxygen tension in the metabolism and regulation of articular and growth plate chondrocytes and progenitor cell phenotypes, and the role of some microenvironmental factors as regulators of chondrocytes.

Minced Cartilage Implantation in Acetabular Cartilage Defects: Case Series with 2-Year Results

OBJECTIVE

The objective was to evaluate clinical outcome and safety of arthroscopic, autologous minced cartilage implantation for acetabular cartilage lesions observed during hip arthroscopy to treat femoroacetabular impingement syndrome (FAIS).

DESIGN

Eleven male patients, average age: 29.4 ± 5.4 years, average body mass index (BMI): 24.2 ± 2.2 kg/m2, scheduled for hip arthroscopy due to FAIS accompanied by an acetabular cartilage lesion were included in the case series. Cartilage tissue was harvested and minced from the loose cartilage flap at the chondrolabral lesion by arthroscopic shaver, augmented with autologous conditioned plasma, implanted into the defect, and fixated by autologous thrombin. Concomitant interventions were performed as indicated. The patients were evaluated preoperatively and at 24-month follow-up, using the International Hip Outcome Tool-12 (iHOT-12) and Visual Analog Scale (VAS) pain score and by magnetic resonance imaging (MRI) using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) grading scale at the 2-year follow-up.

RESULTS

The defect size was on average 3.5 cm2 (1.5-4.5 cm2). From preoperatively to 2 years postoperatively, the iHOT-12 significantly improved from 50.2 ± 18 to 86.5 ± 19 (P < 0.0001), and pain score decreased from 5.6 ± 1.8 to 1.0 ± 1.5 (P < 0.0001) on the Visual Analog Scale pain score. Regarding functional outcome and pain, 10 of the 11 patients and all patients reached the minimal clinically important difference (MCID), respectively. The postoperative average MOCART score was 87.2 (± 9.2). No adverse events or reoperations were observed.

CONCLUSIONS

Arthroscopic, autologous minced cartilage implantation for treating full-thickness acetabular cartilage lesions in FAIS shows statistically and clinically significant improvement at short-term follow-up.

Treatment of Chondral Lesions in the Knee

Articular cartilage injuries are common and lead to early joint deterioration and osteoarthritis. Articular cartilage repair techniques aim at forming a cartilaginous neo-tissue to support the articular load and prevent progressive degeneration. Several techniques are available for this purpose, such as microfracture and chondrocyte transplantation. However, the procedural outcome is often fibrocartilage, which does not have the same mechanical resistance as cartilaginous tissue. Procedures with autologous osteochondral graft have a morbidity risk, and tissue availability limits their use. As such, larger lesions undergo osteochondral transplantation using fresh or frozen grafts. New techniques using minced or particulate cartilage fragments or mesenchymal stem cells are promising. This paper aims to update the procedures for treating chondral lesions of the knee.