Results of Hyaluronic Acid-Based Cell-Free Scaffold Application in Combination With Microfracture for the Treatment of Osteochondral Lesions of the Knee: 2-Year Comparative Study

Chitosan-based scaffold augmentation to microfractures: Stable results at mid-term follow-up in patients with patellar cartilage lesions

Purpose

Patellar cartilage lesions are a frequent and challenging finding in orthopaedic clinical practice. This study aimed to evaluate a chitosan-based scaffold's mid-term clinical and imaging results patients with patellar cartilage lesions.

Methods

Thirteen patients (nine men, four women, 31.3 ± 12.7 years old) were clinically evaluated prospectively at baseline, 12, 24 and at a final minimum follow-up of 60 months (80.2 ± 14.7) with International Knee Documentation Committee (IKDC) subjective, Knee Injury and Osteoarthritis Outcome Score and Tegner scores. A magnetic resonance analysis was performed at the last follow-up using the Magnetic resonance Observation of CArtilage Repair Tissue (MOCART) 2.0 score.

Results

An overall significant clinical improvement in the scores was observed from baseline to all follow-ups, with stable clinical results from 24 months to the mid-term evaluation. The IKDC subjective score passed from 46.3 ± 20.0 at baseline to 70.1 ± 21.5 at the last follow-up (p = 0.029). Symptoms' duration before surgery negatively correlated with the clinical improvement from baseline to the final follow-up (p = 0.013) and sex influenced the improvement of activity level from the preoperative evaluation to the final follow-up, with better results in men (p = 0.049). In line with the clinical findings, positive results were documented in terms of cartilage repair quality with a mean MOCART 2.0 score of 72.4 ± 12.5.

Conclusions

Overall, the use of this chitosan-based scaffold provided satisfactory results with a stable clinical improvement up to mid-term follow-up, which should be confirmed by further high-level studies to be considered a suitable surgical option to treat patients affected by patellar cartilage lesions.

Level of Evidence

Level IV, prospective case series.

Treatment of knee cartilage lesions in 2024: From hyaluronic acid to regenerative medicine

Abstract

Intact articular cartilage plays a vital role in joint homeostasis. Local cartilage repairs, where defects in the cartilage matrix are filled in and sealed to congruity, are therefore important treatments to restore a joint equilibrium. The base for all cartilage repairs is the cells; either chondrocytes or chondrogeneic cells from bone, synovia and fat tissue. The surgical options include bone marrow stimulation techniques alone or augmented with scaffolds, chondrogeneic cell implantations and osteochondral auto- or allografts. The current trend is to choose one-stage procedures being easier to use from a regulatory point of view. This narrative review provides an overview of the current nonoperative and surgical options available for the repair of various cartilage lesions.

Level of Evidence

Level IV.

Rehabilitation of Soccer Players' Knee Injuries: Cartilage Reconstruction, Anterior Cruciate Ligament Surgery, and Intensive Recovery-A Pilot Study

Knee injuries, particularly anterior cruciate ligament (ACL) damage and cartilage defects, are highly prevalent among athletes and affect their sports performance and long-term joint function. The purpose of this research was to evaluate the effectiveness of a comprehensive combination therapy approach for individuals with ACL and cartilage injuries. Twelve professional soccer players aged 18 to 30 years underwent bone-tendon-bone ACL reconstruction, microfracture cartilage repair surgery, and hyaluronic acid scaffold treatment. Early postoperative rehabilitation included immediate supervised physiotherapy and complete weight bearing. Follow-up assessments involved clinical evaluations, functional joint assessments, and magnetic resonance imaging (MRI) scans to measure cartilage defect repair and symptom alleviation. The results showed that patients resumed pain-free activities within 3-4 weeks and returned to their pre-injury level within 4.5 months. MRI demonstrated the absence of inflammatory reactions, repair of marrow edema, and the emergence of new cartilage. Six months and one year after surgery, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Short Form (36) Health Survey (SF-36) questionnaire results demonstrated considerable improvement in patients' health condition and quality of life. Overall, the study suggests that the combination of Hyalofast membranes, microfracture surgery, tissue adhesive, and intensive postoperative physical therapy may be a potential alternative to commonly used treatments for patients with ACL rupture, allowing them to recover efficiently and return to sports activities.

Scaffold-associated procedures are superior to microfracture in managing focal cartilage defects in the knee: A systematic review & meta-analysis

BACKGROUND

Debate continues as to whether surgical treatment with chondral-regeneration devices is superior to microfracture for focal articular cartilage defects in the knee.

PURPOSE

To evaluate the superiority of scaffold-associated chondral-regeneration procedures over microfracture by assessing: (1) Patient-reported outcomes; (2) Intervention failure; (3) Histological quality of cartilage repair.

STUDY DESIGN

A three-concept keyword search strategy was designed, in accordance with PRISMA guidelines: (i) knee (ii) microfracture (iii) scaffold. Four databases (Ovid Medline, Embase, CINAHL and Scopus) were searched for comparative clinical trials (Level I-III evidence). Critical appraisal used two Cochrane tools: the Risk of Bias tool (RoB2) for randomized control trials and the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I). Study heterogeneity permitted qualitative analysis with the exception of three patient-reported scores, for which a meta-analysis was performed.

RESULTS

Twenty-one studies were identified (1699 patients, age range 18-66 years): ten randomized control trials and eleven non-randomized study interventions. Meta-analyses of the International Knee Documentation Committee (IKDC), Knee Injury And Osteoarthritis Outcome Score (KOOS) for pain and activities of daily living, and Lysholm score demonstrated statistically significant improvement in outcomes for scaffold procedures compared to microfracture at two years. No statistical difference was seen at five years.

CONCLUSION

Despite the limitations of study heterogeneity, scaffold-associated procedures appear to be superior to MF in terms of patient-reported outcomes at two years though similar at five years. Future evaluation would benefit from studies using validated clinical scoring systems, reporting failure, adverse events and long-term clinical follow up to determine technique safety and superiority.

Satisfactory clinical outcomes with autologous matrix-induced chondrogenesis in the treatment of grade IV chondral injuries of the knee

OBJECTIVE

The research aims to evaluate short- and medium-term outcomes of patients treated using autologous matrix-induced chondrogenesis (AMIC) with a hyaluronic acid scaffold (Hyalofast, Anika Therapeutics, MA, USA) in grade IV chondral lesions according to the Outerbridge classification in the knee.

METHODS

This is a multicentre, non-randomized, retrospective study conducted between 2017 and 2022. To determine the clinical outcome of the patients, the follow-up was done with the subjective International Knee Documentation Committee (IKDC) score, pre-surgery, and with a follow-up at 12, 24, and 32 months.

RESULTS

Fifty patients (28 female) with a mean age of 45.9 ± 12.7 years were recruited. The mean size of the lesion was 3.5 cm², and the injuries located in the patella (30%) and trochlear groove (24%) were the most frequent. The total IKDC clinical score significantly increased from baseline to the 32 months of follow-up with a mean difference of 36.4 (95% CI, 29.1-43.7, p < 0.001). Besides, there was a statistically significant improvement in all categories of the IKDC (symptoms, sports activities, function, and activity of daily living) compared between pre-surgery and 24 and 32 months of follow-up. The patients younger than 45 years presented better clinical outcomes than older ones with a difference between medians of 10.40 (95% CI, 1.10-11.50, p = 0.0247), and a negative correlation was found between the 32-month IKDC score and the age. In addition, no statistically significant difference was found when comparing the last results of the IKDC between patients with and without associated surgical procedures or between patients with single and several lesions, neither nor between men and women. The level of satisfaction with the procedure of all the patients, on a score of 1-10, was on average 8 ± 1.5.

CONCLUSION

Results of this study indicate that patients who underwent the AMIC procedure with hyaluronic acid scaffold for the treatment of grade IV chondral lesions in the knee presented satisfactory results throughout the follow-up.

LEVEL OF EVIDENCE

Level IV.

Clinical and Magnetic Resonance Imaging Outcomes After Microfracture Treatment With and Without Augmentation for Focal Chondral Lesions in the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Focal cartilage lesions represent a common source of knee pain and disability, with the potential for the development and progression of osteoarthritis. Currently, microfracture (MFx) represents the most utilized first-line surgical treatment for small, focal chondral lesions. Recent investigations have examined methods of overcoming the limitations of MFx utilizing various augmentation techniques.

PURPOSE

To perform a systematic review and meta-analysis evaluating clinical and radiographic outcomes in patients undergoing isolated MFx versus MFx augmented with orthobiologics or scaffolds for focal chondral defects of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed to identify studies evaluating outcomes and adverse events in patients undergoing isolated MFx versus augmented MFx for focal chondral defects in the knee from 1945 to June 1, 2021. Data were extracted from each article that met the inclusion/exclusion criteria. Meta-analyses were performed for all outcomes reported in a minimum of 3 studies.

RESULTS

A total of 14 studies were identified, utilizing 7 different types of injectable augmentation regimens and 5 different scaffolding regimens. Across the 14 studies, a total of 744 patients were included. The mean patient age was 46.8 years (range, 34-58 years), and 58.3% (n = 434/744) of patients were women. The mean final follow-up time was 26.7 months (range, 12-60 months). The mean chondral defect size ranged from 1.3 to 4.8 cm². A post hoc analysis comparing mean improvement in postoperative outcomes scores compared with preoperative values found no significant differences in the improvement in the visual analog scale (VAS), International Knee Documentation Committee (IKDC), or Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores between patients undergoing isolated MFx and those undergoing MFx + augmentation. Patients undergoing MFx + augmentation reported significantly greater improvements in the Lysholm score and postoperative MOCART (magnetic resonance observation of cartilage repair tissue) scores compared with the isolated MFx group.

CONCLUSION

Patients undergoing combined MFx + augmentation reported significant improvements in mean Lysholm and MOCART scores, without significant improvements in VAS, IKDC, or WOMAC scores when compared with patients undergoing isolated MFx.

Evaluation of Electrospun PCL-PLGA for Sustained Delivery of Kartogenin

In this study, kartogenin was incorporated into an electrospun blend of polycaprolactone and poly(lactic-co-glycolic acid) (1:1) to determine the feasibility of this system for sustained drug delivery. Kartogenin is a small-molecule drug that could enhance the outcome of microfracture, a cartilage restoration procedure, by selectively stimulating chondrogenic differentiation of endogenous bone marrow mesenchymal stem cells. Experimental results showed that kartogenin did not affect the electrospinnability of the polymer blend, and it had negligible effects on fiber morphology and scaffold mechanical properties. The loading efficiency of kartogenin into electrospun membranes was nearly 100%, and no evidence of chemical reaction between kartogenin and the polymers was detected by Fourier transform infrared spectroscopy. Analysis of the released drug using high-performance liquid chromatography-photodiode array detection indicated an abundance of kartogenin and only a small amount of its major hydrolysis product. Kartogenin displayed a typical biphasic release profile, with approximately 30% being released within 24 h followed by a much slower, constant rate of release up to 28 days. Although additional development is needed to tune the release kinetics and address issues common to electrospun scaffolds (e.g., high fiber density), the results of this study demonstrated that a scaffold electrospun from biodegradable synthetic polymers is a suitable kartogenin delivery vehicle.

Microfracture versus Enhanced Microfracture Techniques in Knee Cartilage Restoration: A Systematic Review and Meta-Analysis

This study aimed to compare the efficacy and safety of the microfracture (MFx) and microfracture augmented (MFx + ) techniques for the treatment of cartilage defects of the knee. The PubMed and EMBASE databases were searched from 1 January, 1950 to 1 May, 2019. RevMan5.3 was used to perform statistical analysis. Relative risk was calculated for binary variables, and weighted mean difference and standardized mean difference (SMD) were measured for continuous variables. The 95% confidence interval (CI) of each variable was assessed. Thirteen trials with 635 patients were included. There was a significant difference in the Lysholm's score (SMD = 0.26, 95% CI: 0.01-0.50, p = 0.04) and magnetic resonance observation of cartilage repair tissue score (SMD = 14.01, 95% CI: 8.01-20.02, p < 0.01) between the MFx and MFx+ groups. There was no significant difference in the Western Ontario and McMaster Universities Osteoarthritis Index score (SMD =  - 12.40, 95% CI: -27.50 to 32.71, p = 0.11), International Knee Documentation Committee score (SMD = 8.67, 95% CI: -0.92 to 18.27, p = 0.08), visual analog scale score (SMD =  - 0.20, 95% CI: -2.45 to 0.96, p = 0.57), Tegner's score (SMD = 0.26, 95% CI: -0.67 to 1.18, p = 0.59), modified Cincinnati's score (SMD =  - 4.58, 95% CI: -14.31 to 5.14, p = 0.36) and modified International Cartilage Repair Society pain score (SMD = 0.09, 95% CI: -0.37 to 0.55, p = 0.70) between the groups. Results of the pooled analyses of the MFx+ and MFx groups suggested that the MFx+ technique is slightly superior to the MFx technique for the treatment of articular cartilage defects of the knee. Further research is required and future studies should include assessments of the outcomes at long-term follow-ups. Trial registration number is PROSPERO CRD42019135803.

Hyaluronic acid as an adjunct to microfracture in the treatment of osteochondral lesions of the talus: a systematic review of randomized controlled trials

BACKGROUND

Osteochondral lesions of the talus (OLT) are common after ankle trauma. Studies have shown that bioactive substances, such as hyaluronic acid (HA), alone, or in combination, with surgical treatment could improve cartilage regeneration and repair, but the effect of HA on patient reported outcomes is unclear.

METHODS

Literature searches were performed across four databases (PubMed, SPORTDiscus, Scopus, and The Cochrane Library) for randomized controlled trials in which at least one treatment arm involved use of HA as an adjunct to microfracture to treat patients with OLT. Primary outcomes included the American Orthopaedic Foot and Ankle Society scores (AOFAS), and the Visual Analog Scale (VAS) for pain. The level of evidence and methodological quality were evaluated using the Modified Coleman Methodology Score (MCMS).

RESULTS

Three randomized studies were eligible for review with a total of 132 patients (35, 40, 57 patients, respectively) and follow-up ranged from 10.5 to 25 months. Utilization of HA at the time of microfracture resulted in greater improvement in AOFAS scores compared to microfracture alone. The pooled effect size was moderate (Standardized Mean Difference [SMD] 0.45, 95% Confidence Interval [CI] 0.06, 0.84; P = .02) and between-study heterogeneity was low (I-squared = 0%). Utilization of HA during microfracture also led to greater improvement in VAS-pain scores compared to microfracture alone. The pooled effect size was very large (SMD -3.86, 95% CI -4.75, - 2.97; P < .001) and heterogeneity was moderate (I-squared = 69%).

CONCLUSION

Hyaluronic acid injection as an adjunct to arthroscopic MF in OLT provides clinically important improvements in function and pain at short-term follow-up compared to MF alone. Future longer-term follow-up studies are warranted to investigate the durability of MF with HA for treatment of OLT.

Comparison of 3 Cell-Free Matrix Scaffolds Used to Treat Osteochondral Lesions in a Rabbit Model

BACKGROUND

Various cell-free scaffolds are already in use for the treatment of osteochondral defects (OCDs); however, a gold standard material has not yet been defined.

PURPOSE

This study compared the macroscopic, histological, and scanning electron microscopy (SEM) characteristics of Chondro-Gide (CG), MaioRegen (MA), and poly-d,l-lactide-co-caprolactone (PLCL) cell-free scaffolds enhanced with small-diameter microfractures (SDMs) for OCDs in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 54 knees from 27 rabbits were used in this study. Three rabbits were sacrificed at the beginning of the study to form an intact cartilage control group (group IC). An OCD model was created at the center of the trochlea, and SDMs were generated in 24 rabbits. Rabbits with OCDs were divided into 4 groups (n = 12 knees per group) according to the cell-free scaffold applied: CG (group CG), MA (group MA), PLCL (group PLCL), and a control group (group SDM). Half of the rabbits were sacrificed at 1 month after treatment, while the other half were sacrificed at 3 months after treatment. Healed cartilage was evaluated macroscopically (using International Cartilage Regeneration & Joint Preservation Society [ICRS] classification criteria) and histopathologically (using modified O'Driscoll scores and collagen staining). Additionally, cell-free scaffold morphologies were compared using SEM analysis.

RESULTS

ICRS and modified O'Driscoll classification and staining with collagen type 1 and type 2 demonstrated significant differences among groups at both 1 and 3 months after treatment (P < .05). The histological characteristics of the group IC samples were superior to those of all other groups, except group PLCL, at 3 months after treatment (P < .05). In addition, the histological properties of group PLCL samples were superior to those of group SDM samples at both 1 and 3 months after treatment in terms of the modified O'Driscoll scores and type 1 collagen staining (P < .05). Concerning type 2 collagen staining intensity, the groups were ranked from highest to lowest at 3 months after treatment as follows: group PLCL (30.3 ± 2.6) > group MA (26.6 ± 1.2) > group CG (23.3 ± 2.3) > group SDM (18.9 ± 0.9).

CONCLUSION

OCDs treated with enhanced SDM using cell-free PLCL scaffolds had superior histopathological and microenvironmental properties, more hyaline cartilage, and more type 2 collagen compared with those treated using CG or MA scaffolds.

CLINICAL RELEVANCE

OCDs treated with PLCL cell-free scaffolds may have superior histopathological properties and contain more type 2 collagen than do OCDs treated with CG or MA cell-free scaffolds.

Does the Choice of Acellular Scaffold and Augmentation With Bone Marrow Aspirate Concentrate Affect Short-term Outcomes in Cartilage Repair? A Systematic Review and Meta-analysis

BACKGROUND

Matrix-induced chondrogenesis (MIC) is a promising treatment option for critical-size cartilage lesions of the knee; however, there exists substantial heterogeneity in the choice of acellular scaffold matrix for MIC cartilage repairs.

HYPOTHESIS

The choice of acellular matrix will not affect patient outcomes after MIC cartilage repair procedures, and the addition of concentrated bone marrow aspirate (cBMA) will improve short-term patient outcomes regardless of matrix choice.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

Studies were stratified by matrix type: multilayered, single layered, and gel based. Continuous outcomes were analyzed with pairwise meta-analysis using the inverse variance model with random effects applied. Binary outcomes were analyzed as pooled proportions in a single-arm fashion; after which, reconstruction of relative risks (RRs) with confidence intervals was performed using the Katz logarithmic method.

RESULTS

A total of 876 patients were included: 469 received multilayered bioscaffolds; 238, gel-based scaffolds; and 169, single-layered scaffolds. The mean age of patients was 36.2 years (95% CI, 33.9 to 38.4), while the mean lesion size was 3.91 cm² (95% CI, 3.40 to 4.42). The weighted mean follow-up was 23.8 months (95% CI, 20.1 to 27.6). Multilayered bioscaffolds were most effective at improving visual analog scale scores (P = .03; weighted mean difference [WMD], -4.44 [95% CI, -4.83 to -4.06]; P < .001). There were significantly lower risks of incomplete defect filling for gel-based scaffolds when compared with multilayered scaffolds (RR, 0.78 [95% CI, 0.69 to 0.88]; P < .001) and single-layered scaffolds (RR, 0.58 [95% CI, 0.41 to 0.81]; P = .001). Augmentation with cBMA further improved clinical scores across all scaffolds, with significant improvements in Tegner score (P = .02), while decreasing incomplete defect filling rates as well. There was significantly greater improvement in visual analog scale scores (P = .01) for single-layered scaffolds with cBMA augmentation (WMD, -4.88 [95% CI, -5.38 to -4.37]; P < .001) as compared with single-layered scaffolds without cBMA augmentation (WMD, -4.08 [95% CI, -4.46 to -3.71]; P < .001). All significant improvements were below their respective minimum clinically important differences.

CONCLUSION

While cartilage repair with acellular scaffolds provides significant improvements in pain and function for patients, there is insufficient clinical evidence to suggest which scaffold material is the most superior in influencing such improvements. The enhancement of cartilage repair procedures with cBMA may provide further functional improvements and improve defect filling; however, more long-term evidence is required to evaluate the effects.

Application of Biological Composite Materials in the Regeneration of Subchondral Defects and Articular Cartilage in a Synovial Joint: An Experimental Model

Objective: Since the benefits of Nano-material usage have been well documented in orthopedic surgery, this study was conducted to explore the effect of polyvinyl alcohol/nano-hydroxyapatite/polyamide 66 (PVA/n-HA/P66) on repairing of traumatic cartilage defects in rabbit knee joint. Methods: New Zealand white rabbits were used to make a rabbit knee traumatic cartilage defect animal model. All rabbits were randomly located in three groups. Group-A (PVA/n-HA+PA66 implanted in cartilage defects); Group-B (HA nanospheres implanted in cartilage defects)/Gelatin sponge composite scaffold); Group-C (only cartilage defect without implant). The repairment of articular cartilage defects and the general observation were studied by using pathological staining and gene expression of collagen using RT-PCR after 12 weeks. Results: After 12 weeks, we observed a small amount of fibrous tissue growth in group C without soft cell filling. The repaired tissue in group B was stained with immunohistochemical and toluidine blue staining for collagen and type II collagen is positive, but chondrocyte structure is more visible. The relative mRNA expression of type II collagen was higher in group B in comparison to other groups. The results of the Wakitani score were 5.50±2.59 for group A, 8.83±2.79 for group B, 11.50±1.05 for group C. Results showed no significant difference between group B and C; however, significant differences were found in the scoring results between groups A and B, and between-group A and C. Conclusion: This study showed the high effectiveness of PVA/n-HA+PA66 in the treatment of cartilage defects through increasing the expression of type II collagen.

Comparison of All Arthroscopic Implantation of Chitosan-Based Liquid Scaffold and Hyaluronan-Based Soft Scaffold in the Treatment of Condylar Osteochondral Lesions in the Knee

Cell-free scaffolds used in cartilage regeneration are produced from different materials. The aim of this study is to compare the clinical and radiological results of two different scaffolds with hyaluronan- or chitosan-based structure used in the treatment of symptomatic condylar osteochondral lesions. The study comprises 69 patients who were operated for osteochondral lesion repair with hyaluronan- (n = 37) or chitosan-based (n = 32) scaffold. The International Knee Documentation Committee (IKDC), Lysholm Knee Scoring Scale and Visual Analog Scale (VAS) scores were collected for both groups at the preoperative and postoperative 3rd, 12th, and 24th months. Magnetic resonance imaging was performed between the 12th and 15th months postoperatively and this with magnetic resonance observation of cartilage repair tissue (MOCART) scoring were compared. Within group assessments demonstrate significant improvement in IKDC, Lysholm, and VAS scores at postoperative 3rd and 12th months. However, in both groups, IKDC, Lysholm and, VAS scores at the postoperative 24th month indicate no significant further improvement, compared with the 12th month results. There was no significant difference between the groups in terms of IKDC, Lysholm, VAS, and MOCART scores at any time period. This study shows that both scaffolds are useful in cartilage regeneration but have no clinical or radiological superiority to each other. Surgeons should select the method with which they feel comfortable. This is a level III, retrospective comparative study.

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.

Natural Polymeric Scaffolds for Tissue Engineering Applications

Natural polymeric scaffolds can be used for tissue engineering applications such as cell delivery and cell-free supporting of native tissues. This is because of their desirable properties such as; high biocompatibility, tunable mechanical strength and conductivity, large surface area, porous- and extracellular matrix (ECM)-mimicked structures. Specifically, their less toxicity and biocompatibility makes them suitable for several tissue engineering applications. For these reasons, several biopolymeric scaffolds are currently being explored for numerous tissue engineering applications. To date, research on the nature, chemistry, and properties of nanocomposite biopolymers are been reported, while the need for a comprehensive research note on more tissue engineering application of these biopolymers remains. As a result, this present study comprehensively reviews the development of common natural biopolymers as scaffolds for tissue engineering applications such as cartilage tissue engineering, cornea repairs, osteochondral defect repairs, and nerve regeneration. More so, the implications of research findings for further studies are presented, while the impact of research advances on future research and other specific recommendations are added as well.

Accurate Reporting of Concomitant Procedures Is Highly Variable in Studies Investigating Knee Cartilage Restoration

OBJECTIVE

Successful clinical outcomes following cartilage restoration procedures are highly dependent on addressing concomitant pathology. The purpose of this study was to document methods for evaluating concomitant procedures of the knee when performed with articular cartilage restoration techniques, and to review their reported findings in high-impact clinical orthopedic studies. We hypothesized that there are substantial inconsistencies in reporting clinical outcomes associated with concomitant procedures relative to outcomes related to isolated cartilage repair.

DESIGN

A total of 133 clinical studies on articular cartilage repair of the knee were identified from 6 high-impact orthopedic journals between 2011 and 2017. Studies were included if they were primary research articles reporting clinical outcomes data following surgical treatment of articular cartilage lesions with a minimum sample size of 5 patients. Studies were excluded if they were review articles, meta-analyses, and articles reporting only nonclinical outcomes (e.g., imaging, histology). A full-text review was then used to evaluate details regarding study methodology and reporting on the following variables: primary cartilage repair procedure, and the utilization of concomitant procedures to address additional patient comorbidities, including malalignment, meniscus pathology, and ligamentous instability. Each study was additionally reviewed to document variation in clinical outcomes reporting in patients that had these comorbidities addressed at the time of surgery.

RESULTS

All studies reported on the type of primary cartilage repair procedure, with autologous chondrocyte implantation (ACI) noted in 43% of studies, microfracture (MF) reported in 16.5%, osteochondral allograft (OCA) in 15%, and osteochondral autograft transplant (OAT) in 8.2%. Regarding concomitant pathology, anterior cruciate ligament (ACL) reconstruction (24.8%) and meniscus repair (23.3%) were the most commonly addressed patient comorbidities. A total of 56 studies (42.1%) excluded patients with malalignment, meniscus injury, and ligamentous instability. For studies that addressed concomitant pathology, 72.7% reported clinical outcomes separately from the cohort treated with only cartilage repair. A total of 16.5% of studies neither excluded nor addressed concomitant pathologies. There was a significant amount of variation in the patient reported outcome scores used among the studies, with the majority of studies reporting International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcomes Score (KOOS) in 47.2% and 43.6% of articles, respectively.

CONCLUSIONS

In this study on knee cartilage restoration, recognition and management of concomitant pathology is inadequately reported in approximately 28% of studies. Only 30% of articles reported adequate treatment of concomitant ailments while scoring their outcomes using one of a potential 18 different scoring systems. These findings highlight the need for more standardized methods to be applied in future research with regard to inclusion, exclusion, and scoring concomitant pathologies with regard to treatment of cartilage defects in the knee.

Cell-Free Scaffolds in Cartilage Knee Surgery: A Systematic Review and Meta-Analysis of Clinical Evidence

OBJECTIVE

To evaluate current evidence and results of cell-free scaffold techniques for knee chondral lesions.

DESIGN

A systematic review was conducted on 3 medical electronic databases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines, and the methodological quality was assessed with a modified Coleman Methodology Score. A meta-analysis was performed on the articles reporting results for visual analogue scale (VAS), Lysholm, and International Knee Documentation Committee (IKDC) scores. In order to investigate the clinical results improvement over time of cell-free cartilage scaffold implantation, all scores were reported and analyzed as improvement from basal scores at 1, 2, and ≥3 years' follow-up.

RESULTS

A total of 23 studies involving 521 patients were included in the qualitative data synthesis. The Coleman score showed an overall poor study quality with the majority of studies reporting results at short-/mid-term follow-up. Sixteen studies were included in the meta-analysis, showing a significant improvement from basal score at 1, 2, and ≥3 years' follow-up. The improvement reached at 1 year remained stable up to the last follow-up for all scores.

CONCLUSIONS

The current literature suggests that cell-free scaffolds may provide good clinical short-/mid-term results; however, the low evidence of the published studies and their short mean follow-up demand further evidence before more definitive conclusions can be drawn on their real potential over time and on their advantages and disadvantages compared to the cell-based strategies for the treatment of cartilage lesions.

The development of natural polymer scaffold-based therapeutics for osteochondral repair

Due to the limited regenerative capacity of cartilage, untreated joint defects can advance to more extensive degenerative conditions such as osteoarthritis. While some biomaterial-based tissue-engineered scaffolds have shown promise in treating such defects, no scaffold has been widely accepted by clinicians to date. Multi-layered natural polymer scaffolds that mimic native osteochondral tissue and facilitate the regeneration of both articular cartilage (AC) and subchondral bone (SCB) in spatially distinct regions have recently entered clinical use, while the transient localized delivery of growth factors and even therapeutic genes has also been proposed to better regulate and promote new tissue formation. Furthermore, new manufacturing methods such as 3D bioprinting have made it possible to precisely tailor scaffold micro-architectures and/or to control the spatial deposition of cells in requisite layers of an implant. In this way, natural and synthetic polymers can be combined to yield bioactive, yet mechanically robust, cell-laden scaffolds suitable for the osteochondral environment. This mini-review discusses recent advances in scaffolds for osteochondral repair, with particular focus on the role of natural polymers in providing regenerative templates for treatment of both AC and SCB in articular joint defects.

Next-Generation Marrow Stimulation Technology for Cartilage Repair: Basic Science to Clinical Application

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Given the relatively high prevalence of full-thickness articular cartilage lesions, including in patients who are <40 years of age, and an inability to detect some of these lesions until the time of arthroscopy, there is value in performing a single-stage cartilage procedure such as marrow stimulation (MS).

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While the positive outcomes of first-generation MS (namely microfracture) have been observed to drop off after 24 months in several studies, improvements have been seen when compared with preoperative conditions for lesions that are 2 to 3 cm2 in size, and MS is considered to be a procedure with technical simplicity, fairly short surgical times, and relatively low morbidity. A recent study showed that autologous chondrocyte implantation (ACI) and osteochondral allograft (OCA) transplantation remain viable treatment options for chondral defects of the knee in the setting of failed MS.

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Basic science principles that have been elucidated in recent years include (1) the creation of vertical walls during defect preparation, (2) an increased depth of subchondral penetration, (3) a smaller awl diameter, and (4) an increased number of subchondral perforations, which are all thought to help resolve issues of access to the mesenchymal stromal cells (MSCs) and the subchondral bone structure/overgrowth issues.

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Pioneering and evolving basic science and clinical studies have led to next-generation clinical applications, such as a hyaluronic acid-based scaffold (ongoing randomized controlled trial [RCT]), an atelocollagen-based gel (as described in a recently published RCT), a micronized allogeneic cartilage scaffold (as described in a recently completed prospective cohort study), and a biosynthetic hydrogel that is composed of polyethylene glycol (PEG) diacrylate and denatured fibrinogen (as described in an ongoing prospective study).

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This review summarizes important points for defect preparation and the recent advances in MS techniques and identifies specific scaffolding augmentation strategies (e.g., mesenchymal augmentation and scaffold stimulation [MASS]) that have the capacity to advance cartilage regeneration in light of recent laboratory and clinical studies.

Return-to-Sport Review for Current Cartilage Treatments

The return to play outcome is an important measure for orthopaedic sports medicine treatments. This variable is especially important when discussing cartilage treatments because there are many different cartilage options available to athletes with articular injuries and this population is particularly interested in the ability to return to activities. Although many outcome variables are considered in any surgical procedure, the return-to-sport variable is focused on an active population and can be tailored to that patient's sport-specific goals. In this article, we will review some of the most recent and up-to-date articles describing return-to-sport outcomes for various knee cartilage treatments. This article will focus on the most common current knee cartilage treatments including microfracture, autologous chondrocyte implantation, osteochondral autograft transplant, and osteochondral allograft transplantation.

Clinical and Radiological Outcomes After Autologous Matrix-Induced Chondrogenesis Versus Microfracture of the Knee: A Systematic Review and Meta-analysis With a Minimum 2-Year Follow-up

Background:

Microfracture (MFx) is the most common procedure for treating chondral lesions in the knee; however, initial improvements decline after 2 years. Autologous matrix-induced chondrogenesis (AMIC) may overcome this shortcoming by combining MFx with collagen scaffolds. However, the outcomes of AMIC and MFx in the knee have not been compared.

Purpose:

To compare the clinical and radiological outcomes of AMIC and MFx over a minimum 2-year follow-up.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search of the MEDLINE, Embase, and Cochrane Library databases identified studies of patients who underwent AMIC or MFx and that reported validated clinical outcome measure and/or radiological evaluation findings at a follow-up of ≥2 years. There were 2 reviewers who performed study selection, a risk of bias assessment, and data extraction.

Results:

Overall, 29 studies were included in this systematic review. The mean improvement on the Lysholm score, Tegner activity scale, and visual analog scale for pain did not differ significantly between the 2 procedures. The mean improvement on the International Knee Documentation Committee (IKDC) subjective score was significantly greater in the AMIC (45.9 [95% CI, 36.2-55.5]) than in the MFx (27.2 [95% CI, 23.3-31.1]) group (P < .001). In addition, the mean magnetic resonance observation of cartilage repair tissue score was significantly higher in the AMIC (69.3 [95% CI, 55.1-83.5]) versus MFx (41.0 [95% CI, 27.3-54.7]) group (P = .005), and the mean adequate defect filling rate on magnetic resonance imaging scans was significantly better in the AMIC (77.3% [95% CI, 66.7%-87.9%]) versus MFx (47.9% [95% CI, 29.2%-66.6%]) group (P = .008) (odds ratio, 1.58 [95% CI, 1.07-2.33]).

Conclusion:

No significant differences in clinical outcomes, except for the IKDC subjective score, were found between the AMIC and MFx groups. Greater improvement in IKDC subjective scores and magnetic resonance imaging findings were seen in patients treated with AMIC compared with MFx at a minimum 2-year follow-up.

Is There a Role for Cartilage Imaging in Athletes?

This article reviews implications for cartilage imaging in athletes in the setting of (1) acute chondral injury diagnosis, (2) evaluation and follow-up of conservative and surgical therapy, and (3) evaluation of cartilage as a surrogate for meniscal function and joint stability. Focal knee cartilage defects are common in athletic populations. Athletes with articular cartilage injury may initially be able to return to sport with conservative therapy; however, a reduction of athletic ability and progression to osteoarthritis is expected in athletes with untreated severe chondral injury. For diagnostic and pre- and postsurgical evaluation purposes, morphological magnetic resonance (MR) assessment of the articular cartilage with high-resolution protocols is crucial. Although not widely implemented for clinical use, compositional MR techniques have great potential for monitoring the development and progression of biochemical and microstructural changes in cartilage extracellular matrix before gross morphological changes occur.

[Effect of microfracture combined with biomimetic hydrogel scaffold on rotator cuff tendon-to-bone healing in rabbits]

OBJECTIVE

To assess the effect of microfracture and biomimetic hydrogel scaffold on tendon-to-bone healing in a rabbit rotator cuff tear model.

METHODS

Gelatin and methacrylic anhydride were used to synthesize gelatin methacryloyl (GelMA). Then the GelMA were treated with ultraviolet rays and vacuum freeze-drying method to obtain a biomimetic hydrogel scaffold. The morphology of the scaffold was observed by gross observation and scanning electron microscope. Degradation of the scaffold was determined at different time points. Twenty-four adult New Zealand rabbits, weighting 2.8-3.5 kg and male or female, were surgically created the bilateral acute rotator cuff tear models. One shoulder was treated with microfractures on the footprint and transosseous suture (control group, n=24). The other shoulder was treated with the same way, except for putting the scaffold on the footprint before transosseous suture (experimental group, n=24). The general conditions of rabbits were observed postoperatively. Tendon-to-bone healing was evaluated by gross observation, Micro-CT, HE staining, and bio-mechanical testing at 4 and 8 weeks after operation.

RESULTS

The scaffold was white and has a porous structure with pore size of 31.7-89.9 μm, which degraded slowly in PBS solution. The degradation rate was about 95% at 18 days. All the rabbits survived to the completion of the experiment. Micro-CT showed that there was no obvious defect and re-tear at the tendon-to-bone interface in both groups. No difference was found in bone mineral density (BMD), tissue mineral density (TMD), and bone volume/total volume (BV/TV) between the two groups at 4 and 8 weeks postoperatively ( P>0.05). HE staining showed that the fibrous scar tissue was the main component at the tendon-to-bone interface in the control group at 4 and 8 weeks postoperatively; the disorderly arranged mineralized cartilage and fibrocartilage formation were observed at the tendon-to-bone interface in the experimental group at 4 weeks, and the orderly arranged cartilage formation was observed at 8 weeks. Besides, the tendon maturation scores of the experimental group were significantly higher than those of the control group at 4 and 8 weeks ( P<0.05). There was no significant difference in the ultimate load to failure and stiffness between the two groups at 4 weeks ( P>0.05); the ultimate load to failure at 8 weeks was significantly higher in the experiment group than in the control group ( t=4.162, P=0.009), and no significant difference was found in stiffness between the two groups at 8 weeks ( t=2.286, P=0.071).

CONCLUSION

Compared with microfracture alone, microfracture combined with biomimetic hydrogel scaffold can enhance tendon-to-bone healing and improve the ultimate load to failure in rabbits.

Clinical Outcomes of an All-Arthroscopic Technique for Single-Stage Autologous Matrix-Induced Chondrogenesis in the Treatment of Articular Cartilage Lesions of the Knee

Purpose

The purpose of this study was to determine the clinical efficacy of an all-arthroscopic approach to autologous matrix-induced chondrogenesis (AMIC) for patients with articular cartilage lesions of the knee joint. We hypothesize that an all-arthroscopic, single-stage AMIC using a hyaluron-based cell-free scaffold improves the postoperative clinical scores for patients with isolated articular cartilage lesions of the knee in the early follow-up period.

Methods

All patients with focal osteochondral lesions of the knee treated with AMIC at our institution from November 2013 to January 2018 were included for analysis. Demographic information, baseline clinical characteristics, perioperative imaging, and follow-up International Knee Documentation Committee (IKDC) scores at 6 and 24 months postoperatively were collected. One-way analysis of variance (ANOVA) with a Bonferroni correction was used to assess for improvement before and after surgery, with statistical significance defined as p < .05.

Results

A total of 22 patients met the inclusion criteria and were analyzed for this study. Articular cartilage lesions were most commonly found at the center of the medial and lateral femoral condyles. Statistically significant improvements in IKDC scores were seen at the 6- and 24-month follow-up periods (p < .05).

Conclusion

An all-arthroscopic technique for single-stage autologous matrix-induced chondrogenesis demonstrates significant early clinical improvement for the treatment of articular cartilage lesions of the knee.

Level of Evidence

4

A Technique Using a Low-Cost, Accessible Cannula to Aid Scaffold Passage in Dry Arthroscopic Cartilage Repair in the Knee

Although autologous matrix-induced chondrogenesis has grown increasingly popular, it can be technically challenging to place the scaffold within the knee efficiently without extending the arthroscopic incisions. To facilitate arthroscopic placement of the matrix into the knee, we developed a technique that involves fashioning a cannula from a standard 5-mL syringe. This technique enables surgeons to conveniently and efficiently place the matrix through the standard arthroscopic ports at minimal cost.

Effects of tranexamic acid on the recovery of osteochondral defects treated by microfracture and acellular matrix scaffold: an experimental study

Background

Microfracture and scaffold application in the treatment of osteochondral defects is still one of the most frequently used methods in the clinic. The most important step in this treatment method is the stabilization of fibrin clot. Tranexamic acid (TA) is an antifibrinolytic agent commonly used in orthopedic surgery in recent years. This study evaluated the effect of local TA application on healing of experimentally induced osteochondral defects on rabbits.

Methods

This paper contains an animal in vivo data and histological outcomes on the effect of TA. Eighteen New Zealand white rabbits were treated unilaterally and cylindrical defects having a width of 4 mm and depth of 5 mm were created in the weight-bearing surfaces of the medial and lateral condyles of the right femur. They were divided into two groups, as group 1 study and group 2 control groups, respectively. One milliliter (ml) of TA was injected into the knee joints of the subjects in group 1. All animals were sacrificed for the extraction of the femur condyles for histologic study at the fourth and eighth weeks after surgery. Histological evaluations were performed by Brittberg and O’Driscoll scores to all samples. Data were organized in a Standard Statistical Package System v.22 software package (SPSS/PC Inc., Chicago, IL.) and reported as mean and median (min-max). Repeated measures ANOVA test was used to compare groups and condyle effects together for each week. p values below 0.05 were considered as statistically significant.

Results

Samples were taken in the fourth and eighth weeks. The regularity of the surface in group 1 was smoother, and the tissue stability was more robust. Mean Brittberg scores in both weeks were statistically higher in group 1 when compared with group 2. In the microscopic evaluation, it was observed that the regeneration of subchondral and cartilage tissues were more rapid and organized in group 1, and the mean O’ Driscoll scores in both weeks were statistically higher in group 1.

Conclusions

Application of TA improves the healing time and tissue stability in osteochondral defects which are implanted a-cellular scaffold after microfracture and should be applicable to humans for the treatment of osteochondral defects.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1144-7) contains supplementary material, which is available to authorized users.

Clinical and radiographic outcomes of chitosan-glycerol phosphate/blood implant are similar with hyaluronic acid-based cell-free scaffold in the treatment of focal osteochondral lesions of the knee joint

PURPOSE

To determine the clinical and radiographic efficacy of chitosan-glycerol phosphate/blood implant versus hyaluronic acid-based cell-free scaffold in patients with focal osteochondral lesion of the knee joint.

METHODS

Clinical data of 46 patients surgically treated using either chitosan-glycerol phosphate/blood implant (25 patients, Group 1) or hyaluronic acid-based cell-free scaffold (21 patients, Group 2) in combination with microfracture were retrospectively evaluated. All lesions were Outerbridge grade III or IV with a mean lesion size of 3.3 ± 0.7 cm². The mean follow-up time was 24.4 months. Visual analogue scale (VAS), Lysholm knee score, and Tegner activity scale were the instruments to evaluate the clinical status. Magnetic resonance observation of cartilage repair tissue (MOCART) system was used to analyze the characteristics of repair tissue.

RESULTS

No significant differences were detected between the groups regarding VAS, Lysholm, and Tegner scores at any time interval during the whole follow-up. The mean post-operative VAS and Lysholm scores at the latest follow-up was significantly better in cases with the lesion size ≤ 3 cm² in Group 1 (p = 0.001, p < 0.001, respectively). However, no significant differences according to the lesion size were detected in Group 2 (n.s.). Complete repair with the filling of the defect was achieved in 7 (28%) of the knees in Group 1 and it was 7 (33.3%) of the knees in Group 2 according to MOCART system at the latest follow-up.

CONCLUSION

Single-stage regenerative cartilage surgery using chitosan-glycerol phosphate/blood implant combined to microfracture for focal osteochondral lesions of the knee revealed similar clinical and radiographic outcomes with hyaluronic acid-based cell-free scaffold at short-term follow-up. However, clinical outcomes of hyaluronan scaffold were less sensitive to defect size than chitosan. With the advantages of no hypertrophic repair tissue formation as well as no need to arthrotomy during surgery, chitosan is an effective choice especially in patients with the lesion size ≤ 3 cm².

LEVEL OF EVIDENCE

III.

Should orthopedic surgeons consider reducing the negative effects of Outerbridge grade 2 patellofemoral chondral lesion on early postoperative recovery during anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to comparatively evaluate the effectiveness of intra-articular PRP and HA injections applied as the treatment of Outerbridge grade 2 chondral lesions in patellofemoral joint during arthroscopic ACL reconstruction.

METHODS

The clinical and radiographic data of 61 patients between 18 and 45 years of age were evaluated. The patients were separated into three groups. Hyaluronic acid injection was applied in 22 knees (Group 1), PRP injection was applied in 18 knees (Group 2), and 21 knees did not have any specific treatment except ACL reconstruction (Group 3). All patients were followed clinically at least for 12 months. Clinical examination of the operated knee, visual analogue scale (VAS) score, Lysholm knee score, and Tegner activity scale were the outcome measures. Routine X-ray and MRI were also performed for all patients at 12-month postoperative follow-up visit.

RESULTS

Although the mean VAS and Lysholm scores at 3-month follow-up were better in Group 1 and 2 than Group 3, the efficacy of intra-articular PRP on healing process regarding progression of the mean VAS and Lysholm scores through 6- and 12-month follow-ups was significantly better and longer than HA. No statistically significant differences were detected according to Tegner activity scale between the groups at 3 and 6 months; however, Group 2 had better activity level than both Group 1 (p < 0.001) and 3 (p < 0.001) at the end of 12 months after surgery.

CONCLUSION

Intra-articular PRP injection applied as the treatment of concomitant Outerbridge grade 2 chondral lesion in patellofemoral joint during ACL reconstruction revealed better and durable clinical outcomes via decreasing the potentially negative effects of chondral pathology on postoperative healing with respect to HA injection.

LEVEL OF EVIDENCE

III-retrospective comparative study.

Combined use of adipose derived stem cells and TGF-β3 microspheres promotes articular cartilage regeneration in vivo

We investigated enhancement of articular cartilage regeneration using a combination of human adipose derived stem cells (hADSCs) and TGF-β3 microspheres (MS) in vivo. Poly-lactic-co-glycolic acid (PLGA)MS were prepared using a solid/oil/water emulsion solvent evaporation-extraction method. The morphology of the MS was evaluated by scanning electron microscopy (SEM). The release characteristic of the TGF-β3 MS was evaluated. A New Zealand rabbit model for experimental osteoarthritis (OA) was established using the anterior medial meniscus excision method. Thirty OA rabbits were divided randomly into three groups according to different treatments of the right knee joints on day 7 after surgery: hADSCs/MS group received injection of both hADSCs and TGF-β3 MS; hADSCs group was injected with hADSCs; control group was injected with normal saline. Gross observation, histological staining and RT-PCR for collagen II and aggrecan) were used to assess the severity of OA and for evaluating the effect of combined use of hADSCs and TGF-β3 MS on articular cartilage regeneration in vivo. The MS were spherical with a smooth surface and the average diameter was 28 ± 2.3 µm. The encapsulation efficiency test showed that 73.8 ± 2.9% of TGF-β3 were encapsulated in the MS. The release of TGF- β3 lasted for at least 30 days. At both 6 and 12 weeks after injection, three groups exhibited different degrees of OA. Histological analysis showed that the hADSCs/MS group exhibited less OA than the hADSCs group, and the control group exhibited the most severe OA. Real-time RT-PCR showed that the gene expression of both collagen II and aggrecan were significantly up-regulated in the hADSCs/MS group. At 12 weeks after injection, the hADSCs/MS group also exhibited less OA than the other two groups. Combined use of hADSCs and TGF-β3 MS promoted articular cartilage regeneration in rabbit OA models.

Emerging Concepts in Treating Cartilage, Osteochondral Defects, and Osteoarthritis of the Knee and Ankle

The management and treatment of cartilage lesions, osteochondral defects, and osteoarthritis remain a challenge in orthopedics. Moreover, these entities have different behaviors in different joints, such as the knee and the ankle, which have inherent differences in function, biology, and biomechanics. There has been a huge development on the conservative treatment (new technologies including orthobiologics) as well as on the surgical approach. Some surgical development upraises from technical improvements including advanced arthroscopic techniques but also from increased knowledge arriving from basic science research and tissue engineering and regenerative medicine approaches. This work addresses the state of the art concerning basic science comparing the knee and ankle as well as current options for treatment. Furthermore, the most promising research developments promising new options for the future are discussed.

Tissue Engineering Strategies for Osteochondral Repair

Tissue engineering strategies have been pushing forward several fields in the range of biomedical research. The musculoskeletal field is not an exception. In fact, tissue engineering has been a great asset in the development of new treatments for osteochondral lesions. Herein, we overview the recent developments in osteochondral tissue engineering. Currently, the treatments applied in a clinical scenario have shown some drawbacks given the difficulty in regenerating a fully functional hyaline cartilage. Among the different strategies designed for osteochondral regeneration, it is possible to identify cell-free strategies, scaffold-free strategies, and advanced strategies, where different materials are combined with cells. Cell-free strategies consist in the development of scaffolds in the attempt to better fulfill the requirements of the cartilage regeneration process. For that, different structures have been designed, from monolayers to multilayered structures, with the intent to mimic the osteochondral architecture. In the case of scaffold-free strategies, they took advantage on the extracellular matrix produced by cells. The last strategy relies in the development of new biomaterials capable of mimicking the extracellular matrix. This way, the cell growth, proliferation, and differentiation at the lesion site are expedited, exploiting the self-regenerative potential of cells and its interaction with biomolecules. Overall, despite the difficulties associated with each approach, tissue engineering has been proven a valuable tool in the regeneration of osteochondral lesions and together with the latest advances in the field, promises to revolutionize personalized therapies.

Editorial Commentary: Can the Outcomes of Microfracture Be Improved to Better Repair Small Cartilage Defects?

The use of a cannulated hollow awl in the microfracture technique can prevent destruction of subchondral bone and potentially enhance the cartilage repair process. Further long-term clinical study would be required to confirm the efficacy of this procedure modification.

Evaluation of reproducibility of the MOCART score in patients with osteochondral lesions of the talus repaired using the autologous matrix-induced chondrogenesis technique

PURPOSE

To evaluate the applicability and reproducibility of magnetic resonance observation of cartilage repair tissue (MOCART) score for morphological evaluation of osteochondral lesions of the talus (OLT) repaired using autologous matrix-induced chondrogenesis (AMIC) technique.

METHODS

Two radiologists (R1-R2) and two orthopaedists (O1-O2) independently reviewed 26 ankle MRIs performed on 13 patients (6 females; age: 38.9 ± 15.9, 14-63) with OLT repaired using AMIC. The MRIs were performed at 6 and 12 months from surgery. For inter/intra-observer agreement evaluation for each variable of the MOCART, we used Cohen's kappa coefficient. Progression of MOCART between 6- and 12-month evaluation was assessed using the Wilcoxon test. The Spearman's correlation coefficient was used to evaluate the correlation between baseline lesion size and MOCART.

RESULTS

The inter-observer agreement between R1 and R2 ranged from poor (adhesions, k = 0.124) to almost perfect (subchondral bone, k = 0.866), between O1 and O2 from absent (effusion, k = -0.190) to poor (surface, k = 0.172), and between R1 and O1 from absent (cartilage interface, k = -0.324) to fair (signal intensity, k = 0.372). The intra-observer agreement of R1 ranged from poor (signal intensity, k = 0.031) to substantial (subchondral lamina, k = 0.677), while that of O1 from absent (subchondral bone, k = -0.061) to substantial (surface, k = 0.663). There was a significant increase of MOCART between 6- and 12-month evaluation of R1 (Z = -2.672; P = 0.008), R2 (Z = -2.721; P = 0.007) and O1 (Z = -3.034; P = 0.002). Conversely, the increase of MOCART of O2 was not significant (Z = -1.665; P = 0.096). Inverse correlation between lesion size at baseline and MOCART was significant at 12-month evaluation (-0.726; P = 0.005).

CONCLUSION

MRI has an important role in the follow-up of surgical repaired OLT, but MOCART score does not seem to be sufficiently reproducible to be applied for this purpose.

Clinical and imaging outcome of osteochondral lesions of the talus treated using autologous matrix-induced chondrogenesis technique with a biomimetic scaffold

BACKGROUND

The purpose of our study was to assess the clinical and imaging outcome of autologous matrix-induced chondrogenesis (AMIC) technique consisting of microfractures followed by the filling of osteochondral lesions of the talus (OLTs) with a cell-free biphasic collagen-hydroxyapatite osteochondral scaffold (MaioRegen).

METHODS

Sixteen patients (eight males, age: 42.6 ± 18.4, range 14-74) with OLT repaired using AMIC technique, with implantation of MaioRegen, were clinically evaluated through the American Orthopedic Foot and Ankle Society Score (AOFAS) and a 10-point Visual Analogue Scale (VAS) pain score after a mean follow-up of 30 ± 16.9 months. The MRI examinations were performed 12 and 24 months after surgery. A paired t-test was applied to compare pre- and post-operative clinical findings (VAS and AOFAS) and Magnetic resonance observation of cartilage repair tissue (MOCART) score changes in the follow-up. To assess the correlation between variation of AOFAS and MOCART scores, the Pearson's correlation coefficient was calculated.

RESULTS

No complications after surgery were encountered. From pre-operative to post-operative values, there was a significant (P < 0.001) reduction of mean VAS pain score (6.3 ± 0.9,range: 4-8 and 2.9 ± 1.8,range: 0-6, respectively) and increase of AOFAS score (60.2 ± 7.8,range: 50-74 and 77.4 ± 16.2,range: 50-100, respectively). Among 16 patients, six (37%) were not satisfied at the end of follow-up, six (37%) were moderately satisfied and four (25%) were highly satisfied. The treatment was considered failed in five out of 16 patients (31%). Among them, four (25%) required re-interventions with implantation of ankle prostheses, whereas one patient was treated with a further AMIC technique combined with autologous bone graft and platelet-rich plasma. The mean MOCART score was 41.9 ± 14.6 (25-70) 12 months after surgery and 51.9 ± 11.6 (30-70) after 24 months, with a statistically significant increase (P = 0.012). However, no correlation was seen between AOFAS and MOCART changes (r = 0.215, p = 0.609).

CONCLUSION

The high rates of treatment failure encountered in our study using MaioRegen need to be confirmed by larger studies and should induce the scientific community questioning the reliability of this biomimetic scaffold for the treatment of OLTs.