Osteochondral Autologous Transplantation

Curcumin Alleviates Osteoarthritis Through the p38MAPK Pathway: Network Pharmacological Prediction and Experimental Confirmation

Objective

Osteoarthritis (OA) is a common degenerative disease worldwide. While curcumin has shown therapeutic effects on OA, its mechanism remains unknown. This study aimed to investigate the molecular mechanism of curcumin in treating OA through network pharmacology and both in vivo and in vitro experiments.

Methods

Curcumin-related targets were obtained using the HERB and DrugBank databases. GeneCards and DisGeNET were used to build a target database for OA. The STRING database was employed to construct protein-protein interaction networks and analyze related protein interactions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and gene ontology enrichment analyses of core targets were performed using Metascape. In addition, Autodock software was utilized for molecular docking validation of curcumin and disease targets. Further validation of the main findings was conducted through in vitro and in vivo experiments. In the in vitro experiments, an inflammation model was constructed through nitric oxide donor (SNP) stimulation of chondrocytes. Subsequently, the regulatory effects of curcumin on core targets and signaling pathways were validated using Western blotting and immunofluorescence staining techniques. In the in vivo experiments, an OA model was established by performing medial meniscectomy on male Sprague-Dawley rats. The therapeutic effects were evaluated using enzyme-linked immunosorbent assays, histologic staining, and micro-computed tomography (micro-CT) techniques.

Results

Core targets of curcumin relevant to OA therapy included tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, matrix metalloproteinase 9 (MMP-9), B-cell lymphoma 2 (BCL-2), and caspase-3. The major biological processes involved oxidative stress and apoptotic processes, among others. The p38 mitogen-activated protein kinase (p38/MAPK) pathway was identified as the most likely pathway involved. In vitro experiments showed that curcumin significantly reduced oxidative stress levels, inhibited the expression of inflammatory factors IL-6 and Cyclooxygenase-2 (COX-2) and downregulated the expression of MMP-9 and MMP-1. In addition, curcumin was found to regulate the expression of BCL-2 and caspase-3 through the p38/MAPK pathway, inhibiting chondrocyte apoptosis. In vivo animal experiments demonstrated that curcumin significantly reduced the expression of OA-related factors (IL-1, IL-6, and TNF-α). Histological analysis and micro-CT results revealed that curcumin treatment significantly increased cartilage thickness, improved cartilage morphology, structure, and function, inhibited cartilage degradation, and enhanced the resorption of subchondral bone in the knee joints of rats with OA.

Conclusion

Curcumin regulates oxidative stress and maintains mitochondrial function, thereby protecting chondrocyte guard. In addition, curcumin attenuates the inflammatory response of chondrocytes by inhibiting the phosphorylation of P38MAPK, slowing down the breakdown of the extrachondral matrix while preventing apoptosis of chondrocytes. Additionally curcumin attenuated cartilage degradation and bone damage while helping to boost bone density.

3D printed osteochondral scaffolds: design strategies, present applications and future perspectives

Articular osteochondral (OC) defects are a global clinical problem characterized by loss of full-thickness articular cartilage with underlying calcified cartilage through to the subchondral bone. While current surgical treatments can relieve pain, none of them can completely repair all components of the OC unit and restore its original function. With the rapid development of three-dimensional (3D) printing technology, admirable progress has been made in bone and cartilage reconstruction, providing new strategies for restoring joint function. 3D printing has the advantages of fast speed, high precision, and personalized customization to meet the requirements of irregular geometry, differentiated composition, and multi-layered boundary layer structures of joint OC scaffolds. This review captures the original published researches on the application of 3D printing technology to the repair of entire OC units and provides a comprehensive summary of the recent advances in 3D printed OC scaffolds. We first introduce the gradient structure and biological properties of articular OC tissue. The considerations for the development of 3D printed OC scaffolds are emphatically summarized, including material types, fabrication techniques, structural design and seed cells. Especially from the perspective of material composition and structural design, the classification, characteristics and latest research progress of discrete gradient scaffolds (biphasic, triphasic and multiphasic scaffolds) and continuous gradient scaffolds (gradient material and/or structure, and gradient interface) are summarized. Finally, we also describe the important progress and application prospect of 3D printing technology in OC interface regeneration. 3D printing technology for OC reconstruction should simulate the gradient structure of subchondral bone and cartilage. Therefore, we must not only strengthen the basic research on OC structure, but also continue to explore the role of 3D printing technology in OC tissue engineering. This will enable better structural and functional bionics of OC scaffolds, ultimately improving the repair of OC defects.

Surface morphology of osteochondral grafts harvested from femoral condyles with free-hand technique: a cadaveric study

PURPOSE

The purpose of this cadaver study was to examine the surface morphology of the osteochondral grafts harvested from the femoral condyles using the free-hand graft harvesting technique.

MATERIALS AND METHODS

One hundred osteochondral grafts were harvested with 6.5 mm chisels at ten different donor sites using the free-hand technique in five paired knee specimens (Mean age: 56.4 years). The cartilage and subchondral bone surface angles were measured through multiplanar reconstruction computerized tomography examination. The cartilage thickness was measured with a MicroScribe G2X digitizer with an accuracy of 0.02 mm. An acceptable congruity could be obtained when these plugs were transferred to a perpendicular socket (articular step-off of less than 1 mm and 0.5 mm) was evaluated.

RESULTS

Four plugs were damaged or broken during harvesting due to technical difficulties; thus remaining 96 plugs were analyzed. The cartilage thickness varied between 1.36 mm and 3.26 mm across the donor sites. The cartilage was the thinnest in the medial intercondylar notch and thickest in the lateral supracondylar notch. Twenty of ninety-six plugs (20.8%) had unacceptable cartilage surface inclination according to the > 0.5 mm protrusion criteria. Of these plugs, 14 were harvested from the lateral intercondylar notch, whereas five of 96 plugs (5.2%) had unacceptable cartilage surface inclination according to the > 1 mm protrusion criteria. Of these plugs, all were harvested from the lateral intercondylar notch.

CONCLUSIONS

High rates of unacceptable plugs (up to 100%) might be harvested from the lateral intercondylar notch. In large chondral lesions that require multiple plugs, lateral and medial supracondylar ridges were the best donor sites for perpendicular plug harvesting, whereas lateral intercondylar notch should be avoided.

Mincing bovine articular cartilage with commercially available shavers reduces the viability of chondrocytes compared to scalpel mincing

PURPOSE

The study aimed to compare the effect of mincing bovine articular cartilage with different shaver blades on chondrocyte viability.

METHODS

Bovine articular cartilage was harvested either with a scalpel or with three different shaver blades (2.5 mm, 3.5 mm, or 4.2 mm) from a commercially available shaver. The cartilage harvested with a scalpel was then minced into fragments smaller than 1 mm3 with a scalpel. All four conditions were cultivated in a culture medium for seven days. After Day 1 and Day 7, the following measurements were performed: metabolic activity, RNA isolation, and gene expression of anabolic (COL2A1 and ACAN) and catabolic genes (MMP1 and MMP13), live/dead staining and visualization using confocal microscopy, and flow cytometric characterization of minced cartilage chondrocytes.

RESULTS

Mincing the cartilage with shavers significantly reduced metabolic activity after one and seven days compared to scalpel mincing (p < 0.001). Gene expression of anabolic genes (COL2A1 and ACAN) was reduced, while catabolic genes (MMP1 and MMP13) were increased after day 7 in all shaver conditions. Confocal microscopy showed a thin line of dead cells at the lesion side with viable cells beneath for the scalpel mincing and a higher number of dead cells diffusely distributed in the shaver conditions. After seven days, there was a significant decrease in viable cells in the shaver conditions compared to scalpel mincing (p < 0.05). Flow cytometric characterization revealed fewer intact cells and proportionally more dead cells in all shaver conditions compared to the scalpel mincing.

CONCLUSION

Mincing bovine articular cartilage with commercially available shavers reduces the viability of chondrocytes compared to scalpel mincing immediately after harvest and after seven days in culture. This suggests that mincing cartilage with a shaver should be considered a matrix rather than a cell therapy.

LEVEL OF EVIDENCE

Level II therapeutic study.

Clinical Potential of Cellular Material Sources in the Generation of iPSC-Based Products for the Regeneration of Articular Cartilage

Inflammatory joint diseases, among which osteoarthritis and rheumatoid arthritis are the most common, are characterized by progressive degeneration of the cartilage tissue, resulting in the threat of limited or lost joint functionality in the absence of treatment. Currently, treating these diseases is difficult, and a number of existing treatment and prevention measures are not entirely effective and are complicated by the patients' conditions, the multifactorial nature of the pathology, and an incomplete understanding of the etiology. Cellular technologies based on induced pluripotent stem cells (iPSCs) can provide a vast cellular resource for the production of artificial cartilage tissue for replacement therapy and allow the possibility of a personalized approach. However, the question remains whether a number of etiological abnormalities associated with joint disease are transmitted from the source cell to iPSCs and their chondrocyte derivatives. Some data state that there is no difference between the iPSCs and their derivatives from healthy and sick donors; however, there are other data indicating a dissimilarity. Therefore, this topic requires a thorough study of the differentiation potential of iPSCs and the factors influencing it, the risk factors associated with joint diseases, and a comparative analysis of the characteristics of cells obtained from patients. Together with cultivation optimization methods, these measures can increase the efficiency of obtaining cell technology products and make their wide practical application possible.

Osteochondral Interface: Regenerative Engineering and Challenges

Osteochondral (OC) defects are debilitating for patients and represent a significant clinical problem for orthopedic surgeons as well as regenerative engineers due to their potential complications, which are likely to lead to osteoarthritis and related diseases. If they remain untreated or are treated suboptimally, OC lesions are known to impact the articular cartilage and the transition from cartilage to bone, that is, the cartilage-bone interface. An important component of the OC interface, that is, a selectively permeable membrane, the tidemark, still remains unaddressed in more than 90% of the published research in the past decade. This review focuses on the structure, composition, and function of the OC interface, regenerative engineering attempts with different scaffolding strategies and challenges ahead of us in recapitulating the native OC interface. There are different schools of thought regarding the structure of the native OC interface: stratified and graded. The former assumes the cartilage-to-bone interface to be hierarchically divided into distinct yet continuous zones of uncalcified cartilage-calcified cartilage-subchondral bone. The latter assumes the interface is continuously graded, that is, formed by an infinite number of layers. The cellular composition of the interface, either in respective layers or continuously changing in a graded manner, is chondrocytes, hypertrophic chondrocytes, and osteoblasts as moved from cartilage to bone. Functionally, the interface is assumed to play a role in enabling a smooth transition of loads exerted on the cartilage surface to the bone underneath. Regenerative engineering involves, first, a characterization of the native OC interface in terms of the composition, structure, and function, and, then, proposes the appropriate biomaterials, cells, and biomolecules either alone or in combination to eventually form a structure that mimics and functionally behaves similar to the native interface. The major challenge regarding regeneration of the OC interface appears to lie, in addition to others, in the formation of tidemark, which is a thin membrane separating the OC interface into two distinct zones: the avascular OC interface and the vascular OC interface. There is a significant amount of literature on regenerative approaches to the OC interface; however, only a small portion of them consider the importance of tidemark. Therefore, this review aims at highlighting the significance of the structural organization of the components of the OC interface and increasing the awareness of the orthopedics community regarding the importance of tidemark formation after clinical interventions or regenerative engineering attempts.

Compressibility of Osteochondral Autograft Transfer Donor Grafts: A Comparison of Different Donor Regions and How Much Shortening Occurs of Plugs After Impaction

Background

Osteochondral autograft transfer (OAT) is a useful technique for full-thickness cartilage lesions of the distal femur. Various techniques recommend harvesting a plug 2 mm longer than the recipient hole to allow for graft impaction. Grafts with limited compressibility may not sit flush when impacted.

Purpose

To compare the compressibility/shortening of OAT donor plug regions from the distal femur of human cadaveric knees after impaction.

Study Design

Controlled laboratory study.

Methods

A total of 20 cadaveric knees (mean age, 70.3 ± 8.4 years) were divided into 4 donor regions: medial intercondylar (IC) notch, lateral IC notch, medial trochlea, and lateral trochlea. Each region was subdivided into 4 zones: far superior (FSZ), middle superior (MSZ), middle inferior (MIZ), and far inferior (FIZ). A total of 320 grafts (6-mm diameter, 15-mm depth) were extracted, and a custom-built machine was used to strike the graft 5 times using a predetermined energy of 0.11 J. The graft length was measured initially and after each impact. Statistical analysis of the compressibility for each of the 4 regions and all 16 zones was performed utilizing analysis of variance, with post hoc testing using the Fisher's least significant difference.

Results

Compression in the lateral IC notch, medial IC notch, medial trochlea, and lateral trochlea was 2.4 ± 1.5, 2.1 ± 0.7, 3.1 ± 2.2, and 2.1 ± 0.6 mm, respectively, with significant differences between the 4 regions (P < .01) and the most compression in the medial trochlea (P < .01). Subgroup analysis showed that the lateral trochlea had higher compressibility for FIZ versus MIZ (P = .02) and the lateral IC notch had higher compressibility for FSZ versus FIZ and MIZ (P < .05 for both).

Conclusion

Compressibility varied between OAT donor sites in the distal femur. OAT donor grafts showed the highest compressibility in the medial trochlea (3.1 mm) and lateral IC notch FSZ (3.0 mm).

Clinical Relevance

The lateral trochlea, medial IC notch, and the lower zones of the lateral IC notch grafts should not be oversized more than 2 mm in length, as these grafts may not compress adequately.

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.

Allograft Versus Autograft Osteochondral Transplant for Chondral Defects of the Talus: Systematic Review and Meta-analysis

BACKGROUND

It is unclear whether the results of osteochondral transplant using autografts or allografts for talar osteochondral defect are equivalent.

PURPOSE

A systematic review of the literature was conducted to compare allografts and autografts in terms of patient-reported outcome measures (PROMs), MRI findings, and complications.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

This study was conducted according to the PRISMA guidelines. The literature search was conducted in February 2021. All studies investigating the outcomes of allograft and/or autograft osteochondral transplant as management for osteochondral defects of the talus were accessed. The outcomes of interest were visual analog scale (VAS) score for pain, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Data concerning the rates of failure and revision surgery were also collected. Continuous data were analyzed using the mean difference (MD), whereas binary data were evaluated with the odds ratio (OR) effect measure.

RESULTS

Data from 40 studies (1174 procedures) with a mean follow-up of 46.5 ± 25 months were retrieved. There was comparability concerning the length of follow-up, male to female ratio, mean age, body mass index, defect size, VAS score, and AOFAS score (P > .1) between the groups at baseline. At the last follow-up, the MOCART (MD, 10.5; P = .04) and AOFAS (MD, 4.8; P = .04) scores were better in the autograft group. The VAS score was similar between the 2 groups (P = .4). At the last follow-up, autografts demonstrated lower rate of revision surgery (OR, 7.2; P < .0001) and failure (OR, 5.1; P < .0001).

CONCLUSION

Based on the main findings of the present systematic review, talar osteochondral transplant using allografts was associated with higher rates of failure and revision compared with autografts at midterm follow-up.

Surgical Management of Focal Chondral Defects of the Talus: A Bayesian Network Meta-analysis

BACKGROUND

No consensus has been reached regarding the optimal surgical treatment for focal chondral defects of the talus.

PURPOSE

A Bayesian network meta-analysis was conducted to compare the clinical scores and complications of mosaicplasty, osteochondral auto- and allograft transplant, microfracture, matrix-assisted autologous chondrocyte transplant, and autologous matrix-induced chondrogenesis (AMIC) for chondral defects of the talus at midterm follow-up.

STUDY DESIGN

Bayesian network meta-analysis; Level of evidence, 4.

METHODS

This Bayesian network meta-analysis followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Embase, Google Scholar, and Scopus databases were accessed in February 2021. All clinical trials comparing 2 or more surgical interventions for the management of chondral defects of the talus were accessed. The outcomes of interest were visual analog scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, rate of failure, and rate of revision surgery. The network meta-analysis were performed through the routine for Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measure was used for dichotomous variables, and the standardized mean difference (SMD) was used for continuous variables.

RESULTS

Data from 13 articles (521 procedures) were retrieved. The median length of the follow-up was 47.8 months (range, 31.7-66.8 months). Analysis of variance revealed no difference between the treatment groups at baseline in terms of age, sex, body mass index, AOFAS score, VAS score, and mean number of defects. AMIC demonstrated the greatest AOFAS score (SMD, 11.27) and lowest VAS score (SMD, -2.26) as well as the lowest rates of failure (LOR, 0.94) and revision (LOR, 0.94). The test for overall inconsistency was not significant.

CONCLUSION

At approximately 4 years of follow-up, the AMIC procedure for management of focal chondral defects of the talus produced the best outcome.

In vitro Cartilage Regeneration Regulated by a Hydrostatic Pressure Bioreactor Based on Hybrid Photocrosslinkable Hydrogels

Because of the superior characteristics of photocrosslinkable hydrogels suitable for 3D cell-laden bioprinting, tissue regeneration based on photocrosslinkable hydrogels has become an important research topic. However, due to nutrient permeation obstacles caused by the dense networks and static culture conditions, there have been no successful reports on in vitro cartilage regeneration with certain thicknesses based on photocrosslinkable hydrogels. To solve this problem, hydrostatic pressure (HP) provided by the bioreactor was used to regulate the in vitro cartilage regeneration based on hybrid photocrosslinkable (HPC) hydrogel. Chondrocyte laden HPC hydrogels (CHPC) were cultured under 5 MPa HP for 8 weeks and evaluated by various staining and quantitative methods. Results demonstrated that CHPC can maintain the characteristics of HPC hydrogels and is suitable for 3D cell-laden bioprinting. However, HPC hydrogels with concentrations over 3% wt% significantly influenced cell viability and in vitro cartilage regeneration due to nutrient permeation obstacles. Fortunately, HP completely reversed the negative influences of HPC hydrogels at 3% wt%, significantly enhanced cell viability, proliferation, and extracellular matrix (ECM) deposition by improving nutrient transportation and up-regulating the expression of cartilage-specific genes, and successfully regenerated homogeneous cartilage with a thickness over 3 mm. The transcriptome sequencing results demonstrated that HP regulated in vitro cartilage regeneration primarily by inhibiting cell senescence and apoptosis, promoting ECM synthesis, suppressing ECM catabolism, and ECM structure remodeling. Evaluation of in vivo fate indicated that in vitro regenerated cartilage in the HP group further developed after implantation and formed homogeneous and mature cartilage close to the native one, suggesting significant clinical potential. The current study outlines an efficient strategy for in vitro cartilage regeneration based on photocrosslinkable hydrogel scaffolds and its in vivo application.

Triplane osteotomy combined with talar non-weight-bearing area autologous osteochondral transplantation for osteochondral lesions of the talus

Background

Traditional medial malleolar osteotomy combined with autologous osteochondral transplantation (AOT) is mostly used in the treatment of osteochondral lesions of the talus (OLTs), but with high osteotomy and donor site complications. We hypothesis a new triplane medial malleolar osteotomy combined with AOT from non-weight-bearing area of the talus could be a promising choice for OLTs.

Methods

We reviewed all the symptomatic OLTs patients who received AOT with triplane osteotomy of the medial malleolus between September 2015 and December 2017 in our department. According to the inclusion and exclusion criteria, 23 patients (23 ankles), including 14 males and 9 females, were included in the study. The mean age was 35.6 years. The mean size of the lesion area was 141.5 mm². According Ferkel’s classification, including 5 type I, 11 typeIIa and 7 typeIIb. The visual analog scale (VAS) for pain during walking and the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score were used for the pre- and postoperative evaluations. In addition, the incorporation of the grafts was assessed by computed tomography (CT).

Results

All patients had a minimum follow-up of 22 months, with an average of 37.1 months. The mean time from osteotomy to full weight-bearing activity was 8.1 ± 2.3 weeks (range, 5–12 weeks). The mean VAS score improved from 5.6 ± 0.7 preoperatively to 0.7 ± 1.0 postoperatively (P < 0.01). The AOFAS ankle-hindfoot score improved significantly in all domains (P < 0.01). Twenty-one patients returned to sport at their previous level, and 2 returned at a lower level compared with preinjury (mean return to play, 7.4 months). According to CT, the medial malleolus recovered in all patients, and the graft was incorporated well. One patient suffered from flexor hallucis longus tendon discomfort due to internal fixation screw irritation posteromedial to the ankle. The general complication rate was 4.3% (1/23).

Conclusions

These results indicate that AOT combined with medial malleolus triplane osteotomy maybe a viable option for OLTs. Patients could perform weight-bearing exercise and return to sport as early as possible, with a lower rate of complications at the osteotomy site and donor site. However, the large sample well-designed prospective comparative studies are still needed.

Cadaveric Analysis of Exposure of the Talar Articular Surface Through the Posteromedial Approach

The purpose of this cadaveric study is to assess the talar articular surface visible through a modified posterior medial approach to the ankle joint for talar osteochondral defects. Ten fresh frozen cadaveric specimens were included. The talar surface area was outlined utilizing a marker. The talus was removed to measure the medial to lateral length and posterior to anterior length using a flexible ruler. A skin incision was made posterior to the medial malleolus. The incision was deepened through the flexor retinaculum. Dissection was carried between the posterior tibial and flexor digitorum longus tendons through the posterior tibial tendon sheath in order to access the posteromedial ankle joint. The posterior tibiofibular ligament should remain intact. A Hintermann distractor was then inserted to distract the ankle joint. The average articular cartilage visible from medial to lateral was 1.90 (68.6%) centimeters, while from posterior to anterior was 2.00 (43.6%) centimeters. Medial malleolar osteotomy is often required to visualize posteromedial talar osteochondral defects that are difficult to visualize with standard anterior ankle arthroscopy. Our study suggests that the modified posteromedial approach between the posterior tibial and flexor digitorum longus tendons and utilizing a Hintermann distractor allows for visualization of common posterior and central-medial lesions. When considering the anatomic 9-zone grid scheme proposed by Raikin et al, zone 4, 7, and 8 lesions can be assessed with this approach. A clinical study should be undertaken to evaluate the morbidity of this approach.

Surgical management of focal chondral defects of the knee: a Bayesian network meta-analysis

Background

Focal chondral defects of the knee are common. Several surgical techniques have been proposed for the management of chondral defects: microfractures (MFX), osteochondral autograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC) and autologous chondrocyte implantation (ACI)—first generation (pACI), second generation (cACI) and third generation (mACI). A Bayesian network meta-analysis was conducted to compare these surgical strategies for chondral defects in knee at midterm follow-up.

Methods

This Bayesian network meta-analysis was conducted according to the PRISMA extension statement for reporting of systematic reviews incorporating network meta-analyses of health care interventions. PubMed, Google Scholar, Embase and Scopus databases were accessed in July 2021. All the prospective comparative clinical trials investigating two or more surgical interventions for chondral defects of the knee were accessed. The network meta-analyses were performed through a Bayesian hierarchical random-effects model analysis. The log odds ratio (LOR) effect measures were used for dichotomic variables, while the standardized mean difference (SMD) for the continuous variables.

Results

Data from 2220 procedures (36 articles) were retrieved. The median follow-up was 36 (24 to 60) months. The ANOVA test found good baseline comparability between symptoms duration, age, sex and body mass index. AMIC resulted in higher Lysholm score (SMD 3.97) and Tegner score (SMD 2.10). AMIC demonstrated the lowest rate of failures (LOR −0.22) and the lowest rate of revisions (LOR 0.89). As expected, MFX reported the lower rate of hypertrophy (LOR −0.17) followed by AMIC (LOR 0.21). No statistically significant inconsistency was found in the comparisons.

Conclusion

AMIC procedure for focal chondral defects of the knee performed better overall at approximately 3 years’ follow-up.

AMIC for traumatic focal osteochondral defect of the talar shoulder: a 5 years follow-up prospective cohort study

BACKGROUND

Autologous Matrix-Induced Chondrogenesis (AMIC) is addressed to osteochondral defects of the talus. However, evidence concerning the midterm efficacy and safety of AMIC are limited. This study assessed reliability and feasibility of AMIC at 60 months follow-up. We hypothesize that AMIC leads to good clinical outcome at midterm follow-up.

METHODS

Surgeries were approached with an arthrotomy via malleolar osteotomy. A resorbable porcine I/III collagen membrane (Chondro-Gide®, Geistlich Pharma AG, Wolhusen, Switzerland) was used. Patients were followed at 24 and 60 months. The primary outcome of interest was to analyse the Foot Function Index (FFI), and the subscale hindfoot of the American Orthopaedic Foot and Ankle Score (AOFAS). Complications such as failure, revision surgeries, graft delamination, and hypertrophy were also recorded. The secondary outcome of interest was to investigate the association between the clinical outcome and patient characteristics at admission.

RESULTS

Data from 19 patients were included. The mean age at admission was 47.3 ± 13.2 years, and the mean BMI 24.1 ± 4.9 kg/m². 53% (10 of 19 patients) were female. At a mean of 66.2 ± 11.6 months, the FFI decreased at 24-months follow-up of 22.5% (P = 0.003) and of further 1.3% (P = 0.8) at 60-months follow-up. AOFAS increased at 24-months follow-up of 17.2% (P = 0.003) and of further 3.4 (P = 0.2) at 60-months follow-up. There were two symptomatic recurrences within the follow-up in two patients. There was evidence of a strong positive association between FFI and AOFAS at baseline and the same scores last follow-up (P = 0.001 and P = 0.0002, respectively).

CONCLUSION

AMIC enhanced with cancellous bone graft demonstrated efficacy and feasibility for osteochondral defects of the talus at five years follow-up. The greatest improvement was evidenced within the first two years. These results suggest that clinical outcome is influenced by the preoperative status of the ankle. High quality studies involving a larger sample size are required to detect seldom complications and identify prognostic factors leading to better clinical outcome.

LEVEL OF EVIDENCE

II, prospective cohort study.

Autologous Chondrocyte Implantation and Mesenchymal Stem Cells for the Treatments of Chondral Defects of the Knee- A Systematic Review

BACKGROUND

There is still a lack of consensus about the best treatment of chondral defects of the knee. We conducted a systematic PRISMA review to evaluate clinical outcomes of Autologous Chondrocyte Implantation (ACI) and Mesenchymal Stem Cell (MSC) injections for the treatment of focal chondral defects of the knee.

METHODS

A systematic review of literature was performed according to the PRISMA guidelines. All the articles reporting data on ACI and MSC treatments for chondral defects of the knee were considered for inclusion. The main databases were accessed: PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar. The statistical analysis was performed using the Review Manager Software.

RESULTS

In the p-ACI group (987 knees), the Cincinnati Score improved by 18.94% (p=0.1), VAS by 38% (p=0.01), Tegner score by 19.11% (p=0.03), Lysholm score by 22.40% (p=0.01), IKCD by 27.36% (p=0.003). In the c-ACI group (444 knees), the Cincinnati Score improved by 23.80% (p=0.08), KOOS by 23.48% (p=0.03), VAS by 33.2% (p=0.005), IKDC by 33.30% (p=0.005). In the m-ACI group (599 knees), the Cincinnati Score improved by 26.80% (p=0.08), KOOS by 31.59% (p=0.1), VAS by 30.43% (p=0.4), Tegner score by 23.1% (p=0.002), Lysholm score by 31.14% (p=0.004), IKCD by 30.57% (p<0.001). In the MSCs group (291 knees), the KOOS improved by 29.7% (p=0.003), VAS by 41.89% (p<0.001), Tegner score by 25.81% (p=0.003), Lysholm score by 36.96% (p<0.001), IKCD by 30.57% (p=0.001).

CONCLUSION

Both ACI and MSC therapies can be considered as a concrete solution to treat focal chondral defects of the knee.

Graphene Oxide-Doped Gellan Gum-PEGDA Bilayered Hydrogel Mimicking the Mechanical and Lubrication Properties of Articular Cartilage

Articular cartilage (AC) is a specialized connective tissue able to provide a low-friction gliding surface supporting shock-absorption, reducing stresses, and guaranteeing wear-resistance thanks to its structure and mechanical and lubrication properties. Being an avascular tissue, AC has a limited ability to heal defects. Nowadays, conventional strategies show several limitations, which results in ineffective restoration of chondral defects. Several tissue engineering approaches have been proposed to restore the AC's native properties without reproducing its mechanical and lubrication properties yet. This work reports the fabrication of a bilayered structure made of gellan gum (GG) and poly (ethylene glycol) diacrylate (PEGDA), able to mimic the mechanical and lubrication features of both AC superficial and deep zones. Through appropriate combinations of GG and PEGDA, cartilage Young's modulus is effectively mimicked for both zones. Graphene oxide is used as a dopant agent for the superficial hydrogel layer, demonstrating a lower friction than the nondoped counterpart. The bilayered hydrogel's antiwear properties are confirmed by using a knee simulator, following ISO 14243. Finally, in vitro tests with human chondrocytes confirm the absence of cytotoxicity effects. The results shown in this paper open the way to a multilayered synthetic injectable or surgically implantable filler for restoring AC defects.

A Biomimetic Biphasic Scaffold Consisting of Decellularized Cartilage and Decalcified Bone Matrixes for Osteochondral Defect Repair

It is challenging to develop a biphasic scaffold with biomimetic compositional, structural, and functional properties to achieve concomitant repair of both superficial cartilage and subchondral bone in osteochondral defects (OCDs). This study developed a biomimsubchondraletic biphasic scaffold for OCD repair via an iterative layered lyophilization technique that controlled the composition, substrate stiffness, and pore size in each phase of the scaffold. The biphasic scaffold consisted of a superficial decellularized cartilage matrix (DCM) and underlying decalcified bone matrix (DBM) with distinct but seamlessly integrated phases that mimicked the composition and structure of osteochondral tissue, in which the DCM phase had relative low stiffness and small pores (approximately 134 μm) and the DBM phase had relative higher stiffness and larger pores (approximately 336 μm). In vitro results indicated that the biphasic scaffold was biocompatible for bone morrow stem cells (BMSCs) adhesion and proliferation, and the superficial DCM phase promoted chondrogenic differentiation of BMSCs, as indicated by the up-regulation of cartilage-specific gene expression (ACAN, Collagen II, and SOX9) and sGAG secretion; whereas the DBM phase was inducive for osteogenic differentiation of BMSCs, as indicated by the up-regulation of bone-specific gene expression (Collagen I, OCN, and RUNX2) and ALP deposition. Furthermore, compared with the untreated control group, the biphasic scaffold significantly enhanced concomitant repair of superficial cartilage and underlying subchondral bone in a rabbit OCD model, as evidenced by the ICRS macroscopic and O’Driscoll histological assessments. Our results demonstrate that the biomimetic biphasic scaffold has a good osteochondral repair effect.

Cartilage Micrografts as a Novel Non-Invasive and Non-Arthroscopic Autograft Procedure for Knee Chondropathy: Three-Year Follow-Up Study

(1) Background: Focal chondral defects of the knee can significantly impair patient quality of life. Although different options are available, they are still not conclusive and have several limitations. The aim of this study was to evaluate the role of autologous cartilage micrografts in the treatment of knee chondropathy. (2) Methods: Eight patients affected by knee chondropathy were evaluated before and after 6 months and 3 years following autologous cartilage micrografts by magnetic resonance imaging (MRI) for cartilage measurement and clinical assessment. (3) Results: All patients recovered daily activities, reporting pain reduction without the need for analgesic therapy; Oxford Knee Score (OKS) was 28.4 ± 6 and 40.8 ± 6.2 and visual analogue scale (VAS) was 5.5 ± 1.6 and 1.8 ± 0.7 before and after 6 months following treatment, respectively. Both scores remained stable after 3 years. Lastly, a significant improvement of the cartilage thickness was observed using MRI after 3 years. (4) Conclusions: Autologous cartilage micrografts can promote the formation of new cartilage, and could be a valid approach for the treatment of knee chondropathy.

Postoperative Management for Articular Cartilage Surgery in the Knee

The postoperative rehabilitation team plays a crucial role in optimizing outcomes after articular cartilage surgery. A comprehensive approach to postoperative physical therapy that considers the type of surgery, location in the knee, concurrent procedures, and patient-specific factors is imperative. While postoperative rehabilitation protocols should be specific to the patient and type of surgery performed and include phased rehabilitation goals and activities, the key principles for postoperative rehabilitation apply across the spectrum of articular cartilage surgeries and patients. These key principles consist of preoperative assessments that include physical, mental, and behavioral components critical to recovery; education and counseling with respect to expectations and compliance; and careful monitoring and adjustments throughout the rehabilitation period based on consistent communication among rehabilitation, surgical, and imaging teams to ensure strict patient compliance with restrictions, activities, and timelines to optimize functional outcomes after surgery.

Wide Variation in Methodology in Level I and II Studies on Cartilage Repair: A Systematic Review of Available Clinical Trials Comparing Patient Demographics, Treatment Means, and Outcomes Reporting

BACKGROUND

The management of complex cartilage pathology in young, otherwise healthy patients can be difficult.

PURPOSE

To determine the nature of the design, endpoints chosen, and rate at which the endpoints were met in published studies and ongoing clinical trials that investigate cartilage repair and restoration procedures.

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the publicly available level I/II literature and of the publicly listed clinical trials regarding cartilage repair and restoration procedures for the knee was conducted adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Seventeen published studies and 52 clinical trials were included. Within the 17 published studies, the most common procedure studied was microfracture (MFX) + augmentation (N = 5; 29.4%) and the most common comparison/control group was MFX (N = 10; 58.8%). In total, 13 different cartilage procedure groups were evaluated. For published studies, the most common patient-reported outcome (PRO) measures assessed is the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analog Scale-Pain (VAS) (N = 10 studies, 58.8% each, respectively). Overall, there are 10 different PROs used among the included studies. Ten studies demonstrate superiority, 5 demonstrate noninferiority, and 2 demonstrate inferiority to the comparison or control groups. For the clinical trials included, the most common procedure studied is MFX + augmentation (N = 16; 30.8%). The most common PRO assessed is KOOS (N = 36 trials; 69.2%), and overall there are 24 different PROs used among the included studies.

CONCLUSIONS

Recently published studies and clinical trials evaluate a variety of cartilage repair and restoration strategies for the knee, most commonly MFX + augmentation, at various time points of outcome evaluation, with KOOS and VAS scores being used most commonly. MFX remains the most common comparison group for these therapeutic investigations. Most studies demonstrate superiority versus comparison or control groups. Understanding the nature of published and ongoing clinical trials will be helpful in the investigation of emerging technologies required to navigate the regulatory process while studying a relatively narrow population of patients.

Scaffold-Free Cartilage Construct from Infrapatellar Fat Pad Stem Cells for Cartilage Restoration

Once damaged, the articular cartilage has a very limited intrinsic capacity for self-renewal due to its avascular nature. If left untreated, damaged cartilage can lead to progressive degeneration of bone and eventually causes pain. Infrapatellar fat pad adipose-derived mesenchymal stromal cells (IPFP-ASCs) has a potential role for cartilage restoration. However, the therapeutic role for IPFP-ASCs remains to be evaluated in an appropriate osteochondral defect model. Thus, this study aimed to investigate the potential of using a three-dimensional (3D) cartilage construct of IPFP-ASCs as a promising source of cells to restore articular cartilage and to attenuate pain associated with the cartilage defect in an osteochondral defect model. The chondrogenic differentiation potential of the 3D cartilage construct derived from IPFP-ASCs was determined before implantation and postimplantation by gene expression and immunohistochemistry analysis. Pain-related behavior was also assessed by using a weight-bearing test. A significant pain-associated with the osteochondral defect was observed in this model in all groups postinduction; however, this pain can spontaneously resolve within 3 weeks postimplantation regardless of implantation of IPFP-ASCs constructs. The expression of SOX9 and COL2A1 genes in addition to protein expression were strongly expressed in 3D construct IPFP-ASCs. The existence of mature chondrocytes, along with significant (p < 0.05) positive immunostaining for type II collagen and aggrecan, were identified in the implanted site for up to 12 weeks compared with the untreated group, indicating hyaline cartilage regeneration. Taken together, this study demonstrated the successful outcome of osteochondral regeneration with scaffold-free IPFP-ASCs constructs in an osteochondral defect rat model. It provides novel and interesting insights into the current hypothesis that 3D construct IPFP-ASCs may offer potential benefits as an alternative approach to repair the cartilage defect. Impact statement This study provides evidence of using the human 3D scaffold-free infrapatellar fat pad adipose-derived mesenchymal stromal cells (IPFP-ASCs) construct to restore the full-thickness osteochondral defect in a rat model. This study showed that chondrogenic features of the construct could be retained for up to 12 weeks postimplantation. The results of this proof-of-concept study support that human 3D scaffold-free IPFP-ASCs construct has potential benefits in promoting the hyaline-like native cartilage restoration, which may be beneficial as a tissue-specific stem cell for cell-based cartilage therapy. There are several clinical advantages of IPFP-ASC including ease and minimal invasive harvesting, chondrogenic inducible property, and tissue-specific progenitors in the knee.

Implementation of Endogenous and Exogenous Mesenchymal Progenitor Cells for Skeletal Tissue Regeneration and Repair

Harnessing adult mesenchymal stem/progenitor cells to stimulate skeletal tissue repair is a strategy that is being actively investigated. While scientists continue to develop creative and thoughtful ways to utilize these cells for tissue repair, the vast majority of these methodologies can ultimately be categorized into two main approaches: (1) Facilitating the recruitment of endogenous host cells to the injury site; and (2) physically administering into the injury site cells themselves, exogenously, either by autologous or allogeneic implantation. The aim of this paper is to comprehensively review recent key literature on the use of these two approaches in stimulating healing and repair of different skeletal tissues. As expected, each of the two strategies have their own advantages and limitations (which we describe), especially when considering the diverse microenvironments of different skeletal tissues like bone, tendon/ligament, and cartilage/fibrocartilage. This paper also discusses stem/progenitor cells commonly used for repairing different skeletal tissues, and it lists ongoing clinical trials that have risen from the implementation of these cells and strategies. Lastly, we discuss our own thoughts on where the field is headed in the near future.

Effectiveness and safety of polydioxanone thread-embedding acupuncture (TEA) and electroacupuncture (EA) treatment for knee osteoarthritis (KOA) patients with postoperative pain: An assessor-blinded, randomized, controlled pilot trial

BACKGROUND

Degenerative knee osteoarthritis (KOA) shows an increase in morbidity with improvement in the living conditions and extended lifespans. Treatment for degenerative KOA has been gaining attention since it significantly affects the life of the elderly population and is also associated with increased expenses for medical services and high socioeconomic costs. Treatments for degenerative KOA include nondrug therapy, drug therapy, and surgical treatment. For cases that show little response to conservative treatment but have not involved severe deformation of the knee, procedures such as arthroscopic surgery, autologous chondrocyte implantation, or autologous osteochondral transplantation can be performed. However, effective treatment is required for patients experiencing sustained knee pain after surgery. Although studies confirming the therapeutic effects of acupuncture or thread-embedding acupuncture (TEA) treatment for degenerative KOA have been reported, clinical studies on a combination of TEA and electroacupuncture (EA) in patients complaining of knee pain after arthroscopic surgery, autologous chondrocyte implantation, or autologous osteochondral transplantation have not yet been reported. Therefore, this study aimed to evaluate the effectiveness and safety of this combination treatment in patients with persistent knee pain after arthroscopic surgery, autologous chondrocyte implantation, or autologous osteochondral transplantation.

METHODS/DESIGN

This study has been designed as a 2-group, parallel, single-center, randomized, controlled, assessor-blinded trial. Thirty-six patients with degenerative KOA who complained of pain even after arthroscopic surgery, autologous chondrocyte implantation, or autologous osteochondral transplantation will be randomized to either the (TEA + EA + Usual care) group or the (Usual care only) group in a 1:1 ratio. The patients in the (TEA + EA + Usual care) group will receive TEA treatment once a week for 4 weeks for a total of 4 sessions and EA twice a week for a total of 8 sessions while continuing usual care. The (Usual care only) group will only receive usual care for 4 weeks. To assess the efficacy of the TEA and EA combination treatment, the visual analogue scale, the Korean version of the Western Ontario and McMaster Universities Osteoarthritis Index, the EuroQol 5-Dimension 5-Level, and the doses of the rescue drug taken will be evaluated at baseline (1W) and weeks 2 (2W), 4 (4W), 6 (6W), and 8 (8W). The primary efficacy endpoint is the mean change in visual analogue scale at week 4 (4W) compared to baseline. Adverse events will be assessed at every visit.

DISCUSSION

This study will provide useful data for evaluating the clinical efficacy and safety of TEA and electroacupuncture combination treatment for improving pain and quality of life after surgery for degenerative KOA.

TRIAL REGISTRATION

Clinical Research Information Service of Republic of Korea (CRIS- KCT0004804), March 6, 2020.

Platelet-Rich Fibrin Facilitates One-Stage Cartilage Repair by Promoting Chondrocytes Viability, Migration, and Matrix Synthesis

The main aim of this study is to develop a one-stage method to combine platelet-rich fibrin (PRF) and autologous cartilage autografts for porcine articular cartilage repair. The porcine chondrocytes were treated with different concentrations of PRF-conditioned media and were evaluated for their cell viability and extracellular glycosaminoglycan (GAG) synthesis during six day cultivation. The chemotactic effects of PRF on chondrocytes on undigested cartilage autografts were revealed in explant cultures. For the in vivo part, porcine chondral defects were created at the medial femoral condyles of which were (1) left untreated, (2) implanted with PRF combined with hand-diced cartilage grafts, or (3) implanted with PRF combined with device-diced cartilage grafts. After six months, gross grades, histological, and immunohistochemical analyses were compared. The results showed that PRF promotes the viability and GAG expression of the cultured chondrocytes. Additionally, the PRF-conditioned media induce significant cellular migration and outgrowth of chondrocytes from undigested cartilage grafts. In the in vivo study, gross grading and histological scores showed significantly better outcomes in the treatment groups as compared with controls. Moreover, both treatment groups showed significantly more type II collagen staining and minimal type I collagen staining as compared with controls, indicating more hyaline-like cartilage and less fibrous tissue. In conclusion, PRF enhances the viability, differentiation, and migration of chondrocytes, thus, showing an appealing capacity for cartilage repair. The data altogether provide evidences to confirm the feasibility of a one-stage, culture-free method of combining PRF and cartilage autografts for repairing articular cartilage defects. From translational standpoints, these advantages benefit clinical applications by simplifying and potentiating the efficacy of cartilage autograft transplants.

Advances of nanotechnology in osteochondral regeneration

In the past few decades, nanotechnology has proven to be one of the most powerful engineering strategies. The nanotechnologies for osteochondral tissue engineering aim to restore the anatomical structures and physiological functions of cartilage, subchondral bone, and osteochondral interface. As subchondral bone and articular cartilage have different anatomical structures and the physiological functions, complete healing of osteochondral defects remains a great challenge. Considering the limitation of articular cartilage to self-healing and the complexity of osteochondral tissue, osteochondral defects are in urgently need for new therapeutic strategies. This review article will concentrate on the most recent advancements of nanotechnologies, which facilitates chondrogenic and osteogenic differentiation for osteochondral regeneration. Moreover, this review will also discuss the current strategies and physiological challenges for the regeneration of osteochondral tissue. Specifically, we will summarize the latest developments of nanobased scaffolds for simultaneously regenerating subchondral bone and articular cartilage tissues. Additionally, perspectives of nanotechnology in osteochondral tissue engineering will be highlighted. This review article provides a comprehensive summary of the latest trends in cartilage and subchondral bone regeneration, paving the way for nanotechnologies in osteochondral tissue engineering. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement.

Enhanced chondrogenic differentiation of equine bone marrow-derived mesenchymal stem cells in zirconia microwell substrata

In human cartilage tissue engineering, three-dimensional zirconia substrata have the potential advantage of producing many uniform cell clusters of controlled size without xenobiotic material, allowing easy clinical application. The objective of this study was to evaluate the possibility of using zirconia porous three-dimensional microwell substrata for chondrogenic differentiation of equine bone marrow-derived mesenchymal stem cells (BMMSCs) in vitro. In regular medium, 8 × 10⁵, 2 × 10⁶, and 5 × 10⁶ equine BMMSCs from five thoroughbred horses were cultured on zirconia microwell substrata for 4 days to allow formation of clusters. The medium was replaced by chondrogenic culture medium. After chondrogenic culture for 7, 14 and 21 days, analysis of collagen type II alpha 1 gene (COL2A1) gene expression and observation of chondrogenic aggregates by scanning electron microscopy (SEM) were performed. SEM showed size-controlled cell clusters and increasing extracellular matrix over time when using 5 × 10⁶ cells. The expression of COL2A1 on day 7 and 14 with 5 × 10⁶ cells was significantly higher than that of conventional pellet culture with 2 × 10⁶ cells. Histological evaluation by immunohistochemical staining for type II collagen (ColII) was performed after chondrogenic culture for 7 days. The clusters showed wide distribution of ColII. The results suggest that the zirconia substrata have the potential to enhance the chondrogenic differentiation of equine BMMSCs, allowing effective equine cartilage tissue engineering without xenobiotic materials.

[Comparison of arthroscopic osteochondral autologous transplantation for articular cartilage injury in young and middle-aged patients]

Objective

To compare the effectiveness of arthroscopic osteochondral autologous transplantation (OAT) in the treatment of young and middle-aged patients with the articular cartilage injury.

Methods

A clinical data of 43 patients (43 knees) with articular cartilage injury, who underwent OAT between January 2008 and August 2016, was retrospectively analyzed. There were 23 patients aged 20-40 years (young group) and 20 patients aged 40-60 years (middle-aged group). The difference in age between the two groups was significant ( t=14.120, P=0.001). There was no significant difference in gender, body mass index, complications, affected side, lesion site, lesion area, and the International Cartilage Repair Society (ICRS) grade of cartilage injury between the two groups ( P>0.05). The function of knee joint was evaluated by Lysholm score and International Knee Documentation Committee (IKDC) score during the follow-up. MRI examination was performed to observe the repair of both receiving and the donor sites.

Results

All the incisions in the two groups were healed by first intention. All patients in the two groups were followed up with an average of 3.6 years (range, 2-8 years). At 2 years after operation, the Lysholm and IKDC scores were significantly improved in the two groups when compared with the preoperative scores ( P<0.05). The Lysholm and IKDC scores in the young group were significantly better than those in the middle-aged group before operation and at 2 years after operation ( P<0.05). However, there was no significant difference in the differences of the Lysholm and IKDC scores between pre- and post-operation between the two groups ( P>0.05). The MRI examination at 2 years after operation showed that both receiving and the donor sites healed well in the two groups.

Conclusion

According to the texture, thickness, elasticity, and lesion area of the cartilage, arthroscopic OAT might be the first choice for the articular cartilage injury in middle-aged patients and can obtain the satisfactory short-term effectiveness.

Osteochondral repair using scaffolds with gradient pore sizes constructed with silk fibroin, chitosan, and nano-hydroxyapatite

Background

One of the main problems associated with the development of osteochondral reparative materials is that the accurate imitation of the structure of the natural osteochondral tissue and fabrication of a suitable scaffold material for osteochondral repair are difficult. The long-term outcomes of single- or bilayered scaffolds are often unsatisfactory because of the absence of a progressive osteochondral structure. Therefore, only scaffolds with gradient pore sizes are suitable for osteochondral repair to achieve better proliferation and differentiation of the stem cells into osteochondral tissues to complete the repair of defects.

Methods

A silk fibroin (SF) solution, chitosan (CS) solution, and nano-hydroxyapatite (nHA) suspension were mixed at the same weight fraction to obtain osteochondral scaffolds with gradient pore diameters by centrifugation, freeze-drying, and chemical cross-linking.

Results

The scaffolds prepared in this study are confirmed to have a progressive structure starting from the cartilage layer to bone layer, similar to that of the normal osteochondral tissues. The prepared scaffolds are cylindrical in shape and have high internal porosity. The structure consists of regular and highly interconnected pores with a progressively increasing pore distribution as well as a progressively changing pore diameter. The scaffold strongly absorbs water, and has a suitable degradation rate, sufficient space for cell growth and proliferation, and good resistance to compression. Thus, the scaffold can provide sufficient nutrients and space for cell growth, proliferation, and migration. Further, bone marrow mesenchymal stem cells seeded onto the scaffold closely attach to the scaffold and stably grow and proliferate, indicating that the scaffold has good biocompatibility with no cytotoxicity.

Conclusion

In brief, the physical properties and biocompatibility of our scaffolds fully comply with the requirements of scaffold materials required for osteochondral tissue engineering, and they are expected to become a new type of scaffolds with gradient pore sizes for osteochondral repair.