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| Experimental model | Anatomical site (defect dimension) and experimental time | Osteochondral treatment | Histological, histomorphometric, and biomechanical methods | Main outcomes | Author |
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| Rodent model |
| Fifty-five rats (6 weeks old) | Cartilage defect (2 mm Ø and 1 mm depth) in the patellar groove for 1 and 2 months | Bilayered collagen scaffold with or without hESC-MSC | (i) ICRS score
(ii) Paraffin embedding
(iii) H&E and Safranin O stainings
(iv) Indentation test on fresh explants submerged in PBS: Young’s equilibrium modulus | Similar trends between the histomorphometric score and biomechanical analysis | Zhang et al. [10] |
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| Nine male athymic nude rats (11 weeks old) | Critical-size defects in the trochlear groove (1.4 mm Ø and 1 mm depth) for 2 months | Micromasses of hPDCs with or without TGF-β1 | (i) Paraffin embedding
(ii) Alcian Blue staining (iii) IHC: Col I, Col II, nuclei, and lubricin
(iv) MicroCT: BV/TV, Tb.Th., Tb.Sp., and Tb.N. | MicroCT showed heterogeneous regeneration across the defects | Mendes et al. [11] |
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| Fifty male Wistar rat (4 months old) | Defects in the trochlear groove (1.5 mm Ø and 1.5 mm depth) for 2 months | MeHA hydrogel seeded with MSCs or chondrogenically primed MSCs cultivated either free loading or dynamically compressed | (i) Paraffin embedding
(ii) Wakitani score
(iii) Safranin O staining
(iv) IHC: Col II | Dynamic compression and chondrogenic priming synergistically improved regenerative properties of MSCs | Lin et al. [12] |
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| Lapine model |
| Twelve young adult NZW rabbits | Defects in the weight-bearing areas of femoral condyles (4 mm of chondral defect followed by a 2 mm hole in the centre of the 4 mm defect) for 3 months | ADM alone (rabADM) or in association with IPFP-MSCs (cells + rabADM) | (i) Paraffin embedding HC: Col I and II
(ii) Quantification of the total area of cartilage repair by 2D analysis | Significant differences in type II collagen staining | Ye et al. [13] |
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| Ten NZW male rabbits (5 months old) | Defects in the medial femoral condyles (4 mm Ø and 4 mm depth) for 40 days | Collagen scaffold alone or seeded with rabbit BMC; half of the animals stimulated by PEMFs | (i) Niederauer score
(ii) Paraffin embedding (sagittal cut)
(iii) Safranin-O/fast green staining
(iv) Modified O’Driscoll score quantification of new cartilaginous tissue over and under the tidemark | Significant effects in Niederauer and O’Driscoll scores and in percentage of cartilage | Veronesi et al. [14] |
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| Twelve female skeletally mature NZW rabbits | Defects in the central medial femoral condyles (3.5 mm Ø and 2 mm depth) for 1.5 months | Bilayered collagen type I/III scaffold seeded with either culture-expanded allogenic chondrocytes (ACI-CHDR) or synovium-derived stem cells (ACI-SMSC) | (i) ICRS subscore and OARSI score
(ii) Paraffin embedding (sagittal cut)
(iii) H&E and Safranin O staining
(iv) IHC: Col II, X (Remmele–Stegner score)
(v) Indentation test on fresh samples: cartilage thickness, instant modulus, and shear modulus | Similar trends among instantaneous and shear modulus and OARSI score | Schmal et al. [15] |
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| Sixteen male NZW rabbits (34 weeks old) | Defects in the patellar groove (3 mm Ø and 2–2.5 mm depth) for 3 months | 3-dimensional constructs fabricated using Col II hydrogel alone (Col II) or associated with auricular chondrocytes (AU-Col II) | (i) Modified ICRS score
(ii) Paraffin embedding (sagittal cut)
(iii) H&E, Masson’s trichrome, and Alcian Blue stainings | Significance in histological scores and defect healing | Wong et al. [16] |
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| Ten male NZW rabbits (10 months old) | Full-thickness cartilage defects in the patellar groove (4 mm in Ø and 3 mm in depth) for 3 weeks | Autologous BMSCs seeded on type I collagen scaffold in association or not with LLLT | (i) Paraffin embedding (sagittal cut)
(ii) H&E staining
(iii) Quantification of new cartilage formation, new bone formation%, measure of inflammation | No significant difference in new cartilage formation and inflammation; significance in new bone formation | Fekrazad et al. [17] |
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| 48 NZW rabbits (6–8 months old) | Defects in the trochlear groove (4 mm Ø and 3 mm depth) for 3 and 9 months | Regenerated silk fibroin scaffold alone (SF) or seeded with autologous chondrocytes (SFC); fibrin glue containing autologous chondrocytes (FGC) | (i) Wakitani score
(ii) Paraffin embedding (sagittal cut)
(iii) Modified O’Driscoll, Keeley and Salter score
(iv) H&E, Alcian Blue and Masson’s trichrome stainings
(v) IHC: Col II
(vi) Indentation test on fresh samples: ultimate compressive strength (UCS) and compressive Young’s modulus | Significant differences in histological scores but not in biomechanical data | Kazemnejad et al. [18] |
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| Twenty-eight female skeletally mature NZW rabbits | Defects in the medial femoral condyle (4 mm Ø and 5 mm depth) for 13 weeks | Autologous BMP‐2-activated muscle tissue directly implanted into OC lesions | (i) Paraffin embedding
(ii) Extended O’Driscoll score
(iii) Safranin O/fast green stainings
(iv) IHC: Col I and II
(v) Quantification of bone area within the subchondral defect
(v) Indentation test on fresh samples: stiffness | Similar trends between the bone area quantification and biomechanics | Betz et al. [19] |
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| Forty-one skeletally mature NZW rabbits | Full-thickness defects in the femoral groove (5 mm Ø and 6 mm depth) for 1, 2, and 6 months | Combined material comprising a scaffold-free tissue-engineered construct (TEC) derived from synovial mesenchymal stem cells and hydroxyapatite (HA) artificial bone (TEC-HA)
Control group: HA artificial bone | (i) Paraffin embedding
(ii) O’Driscoll score
(iii) H&E and Toluidine Blue staining
(iv) Microindentation test (at 6 months): stiffness | Significance in the histological score but not in biomechanics | Shimomura et al. [20] |
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| Nine skeletally mature male NZW rabbits | Defects in the medial femoral condyles (2.7 mm Ø and 4.0 mm depth) for 6.5 months | (i) Poly(1,8-octanediol-co-citrate) (POC) with 60 weight % hydroxyapatite nanocrystals (POC-HA)
(ii) Poly-L-lactide (PLL) | (i) Paraffin embedding (longitudinal cut)
(ii) Niederauer score
(iii) Masson–Goldner trichrome staining
(iv) Quantification of total area and range of depth of tissue ingrowth, active osteoid surface area/total trabecular bone surface area, total osteoid surface area/total trabecular bone surface area, and trabecular bone surface area/total tissue area
(v) Measurement of fibrous capsule widths | No significant differences in all histomorphometric evaluations | Chung et al. [21] |
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| Seven male and female NZW rabbits (13 or 32 months old) | Defects in the trochlear groove (1.5 mm Ø and 2 mm depth drill holes) for 70 days | (i) 10 kDa chitosan/blood implant with fluorescent chitosan tracer
(ii) 40 kDa chitosan/blood implant with fluorescent chitosan tracer | (i) Modified O’Driscoll score
(ii) Paraffin embedding (sagittal cut)
(iii) SafO staining
(iv) IHC: Col I and II
(v) Quantification of total chondral repair tissue area, (including bone overgrowth); percentage SafO, Col-1- or Col-2-positive-stained tissue (excluding bone overgrowth)
(vi) MicroCT on fresh samples: Residual hole depth and residual hole area below the surface | Significant differences in bone morphometry and O’Driscoll scores | Guzmán-Morales et al. [22] |
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| Five male and female NZW rabbits (30-months old) | Defects in the trochlea (microdrill hole defects, 1.4 mm Ø, and 2 mm depth) for 1 and 21 days | 150, 40, and 10 kDa chitosan solutions, mixed with autologous rabbit whole blood and clotted with tissue factor | (i) MicroCT on fresh samples: residual hole depth and residual hole area below the surface
(ii) Paraffin embedding (sagittal cut)
(iii) SafO staining
(iv) IHC: Col I and II
(v) Quantification of GAG, col I or col II (%); distribution of repair tissues in treated defects and volume density of neutrophils and stromal cells
(vi) TRAP quantification | Significant differences in microCT, GAG, col II, and col I quantifications and volume density of neutrophils | Lafantaisie-Favreau et al. [23] |
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| Twenty NZW rabbits (18 weeks old) | Defects in the weight-bearing area of medial femoral condyles (3 mm Ø and 3 mm depth) for 2 weeks and 1, 2, and 4 months | Allogeneic scaffold-free bioengineered chondrocyte pellet (BCP) | (i) Paraffin embedding (sagittal cut)
(ii) Modified O’Driscoll score
(iii) H&E, Safranin O/fast green staining
(iv) IHC: Col I and II, type I and type II
(v) PCNA stainings
(vi) Quantification of % area filled in defect, cartilage thickness, and bone area | Significant differences in the score and cartilage thickness | Cheuk et al. [24] |
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| Forty NZW rabbits (12–15 months old) | Defects in the weight-bearing area of medial femoral condyles (2 mm Ø with 1–1,5 mm depth) for 2 and 4 months | Osteochondral defect (acute osteoarticular injury) | (i) Paraffin embedding (sagittal cut)
(ii)Manking score
(iii) Safranin O/fast green staining
(iv) Sagittal-plane laxity measurement (at 8 and 16 weeks)
(v) Contact stress test on 7 fresh cadaver knees | Significance in the histological score | Vaseenon et al. [25] |
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| Fourty-two adult male NZW rabbits | Defects in the patellar groove (4 mm Ø and 3.5–4 mm depth) for 1.5 and 3 months | Bilayered microporous scaffold with collagen and electrospun poly-L-lactic acid nanofibers (COL-nanofiber) and bilayer COL scaffold, seeded with BMSCs | (i) ICRS score
(ii) Paraffin embedding
(iii) H&E and Safranin O/fast green staining
(iv) Indentation test (at 12 weeks): Young’s moduli on fresh samples placed in PBS at room temperature before testing.
(v) microCT: subchondral bone | Similar trend between histological scoring system and biomechanical test | Zhang et al. [26] |
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| Nine female NZW rabbits (6 months old) | Defects in the medial femoral condyle (4 mm Ø and 4 mm depth) for 3 months | (i) 70/30 poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) scaffold
(ii) 55/45 PEOT/PBT | (i) Histological scoring system (O’Driscoll score) on 2-hydroxyethyl methacrylate (Technovit) embedded samples (thionine staining) (midsagittal cut) | Significance in the histological scoring system | Jansen et al. [27] |
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| Forty-eight NZW rabbits (7 months old) | Defects in the patellar groove (5 mm Ø and 10 mm depth) for 2 weeks and 1, 2, and 4 months | OC defects treated with low-level He-Ne laser therapy (LLLT) 3 times a week | (i) Paraffin embedding (sagittal cut)
(ii) H&E, Toluidine Blue staining
(iii) Pineda score | Significant acceleration of healing at 4 and 6 weeks | Bayat et al. [28] |
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| 20 adult male NZW rabbits | Defects in the femoral epiphysis (6 mm Ø and 8 mm depth) for 2 months | Mineralized HA-alginate scaffold compared to a commercially available collagen-hydroxyapatite composite scaffold | (i) Niederauer score
(ii) PMMA embedding (sagittal cut)
(iii) Stevenel Blue/van Gieson pichrofucsin staining
(iv) Quantification of MAR and BFR
(v) MicroCT on fresh samples: defect BV/TV; defect Tb.Th.; defect Tb.N.; defect Tb.Sp.; peri-implant BV/TV; peri-implant Tb.Th., Tb.N., and Tb.Sp. | Significance in microCT evaluations and not in dynamic morphometric analyses | Filardo et al. [29] |
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| Sixty skeletally immature male NZW rabbits (3 months old) | Full-thickness defects in the trochlear groove (4 mm Ø and 4 mm depth) for 2 and 9 months | Autogenous periosteal grafts under the influence of (i) group a— active intermittent motion (AIM), euthanized at 8 weeks; group B— continuous passive motion (CPM), euthanized at 8 weeks; group C—AIM, euthanized at 36 weeks; (ii) Group D—CPM, euthanized at 36 weeks | (i) Indentation test on fresh samples: elastic stiffness
(ii) paraffin embedding (sagittal cut)
(iii) O’Driscoll score
(iv) H&E, Masson trichrome, and Alcian Blue staining
(v) Quantification of thickness and area of the regenerated tissue; thickness of the normal cartilage surrounding the defect | Significance in thickness of regenerated tissue and in elastic stiffness | Martin-Hernandez et al. [30] |
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| Forty-two male NZW rabbits (7 months old) | Full-thickness defects in the patellar groove (5 mm Ø and 10 mm depth) for 2 and 1, 2, and 4 months | OC defects treated with low-level He-Ne laser therapy (LLLT) 3 times a week | (i) Indentation test on previously frozen samples: instantaneous stiffness, maximum force, equilibrium load, and energy absorption | Significance only in the energy absorption | Javadieh et al. [31] |
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| Twenty mature female NZW rabbits | Defects in the medial femoral condyle (2.5 Ø and 3 mm depth) for 1, 2, and 3 months | OC defects treated with low-dose irradiation | (i) Paraffin embedding
(ii) O’Driscoll score
(iii) H&E and Safranin O staining
(iv) Indentation test on previously frozen samples: cartilage stiffness | No statistical significance was seen in any parameter | Öncan et al. [32] |
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| Thirty-four male NZW rabbits | Full-thickness defects in the medial and lateral femoral condyles (3 mm Ø and 3 mm in depth) for 6 and 12 weeks | Poly(lactic-co-glycolic acid) with or without fibrin as cells carrier: (i) PLGA/Fibrin/BMSCs (PFC group)
(ii) PLGA/BMSCs (PC group) | (i) ICRS score
(ii) Paraffin embedding
(iii) H&E; Alcian Blue; Safranin O staining
(iv) IHC: Col II
(v) Cartilage-specific gene expression
(vi) Quantification of sGAG
(v) Compression test (at 12 weeks) | Similar significant trends in histological score, GAG content and biomechanical strength | Rahman et al. [33] |
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| Thirty-five skeletally mature NZW rabbits (24 weeks old) | Full-thickness defects in the patellar groove (5 mm Ø and 6 mm depth) for 1, 2, and 6 months | (i) Combined material: bTCP-based hybrid implant coupled with a scaffold-free tissue-engineered construct (TEC) derived from synovial mesenchymal stem cells (TEC/bTCP)
(ii) Scaffold-free tissue-engineered construct (TEC) derived from synovial mesenchymal stem cells and hydroxyapatite (HA) artificial bone (TEC/HA) | (i) Histological grading system (resurfacing:0–2) for gross examination
(ii) Paraffin embedding
(iii) Modified O’Driscoll score
(iv) H&E and Toluidine Blue staining
(v) Microindentation test: tissue stiffness | Similar trends among cellular morphology, total histological score, and biomechanics | Shimomura et al. [34] |
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| Five NZW rabbits (5–6 months old) | Defects in the trochlear groove (3 mm Ø and 2 mm depth) for 3 and 6 months | Cell carrier prepared from articular cartilage slices, designated cartilage extracellular matrix- (ECM-) derived particles (CEDPs) seeded with rabbit ACs or ASCs | (i) ICRS score
(ii) Paraffin embedding
(iii) H&E, Toluidine Blue and sirius red staining
(iv) OARSI score
(v) IHC: Col I and II
(vi) Nanoindentation tests on fresh samples (6 months): hardness, contact stiffness and reduced modulus
(vii) MRI: cartilage regeneration
(viii) microCT: Tb.Th. and BV/TV | Same significant trend in histological, microCT, and biomechanical evaluations | Yin et al. [35] |
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| Eighteen NZW rabbits (15 weeks old) | Defects in the medial and lateral femoral condyles (3 mm Ø and 3 mm depth) for 2, 4, and 6 months | Expandable gelatin scaffold seeded with rabbit chondrocytes (C + S group) compared to OC defects treated with allogenic chondrocyte injection (positive control), scaffold alone (S) and empty defect | (i) O’Driscoll score
(ii) Paraffin embedding
(iii) H&E, Alcian Blue stainings
(iv) Quantification of integration, apposition, and disintegration of regenerated tissue
(v) IHC: Col I, II, and X and S-100
(vi) Compression test on fresh samples | Similar trend among the macroscopic score, histomorphometry, and compressive strength at each time point | Wang et al. [36] |
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| Twenty-seven NZW rabbits (3 months old) | Full-thickness defects in the trochlea (4 mm Ø and 4 mm depth) for 6, 12, or 24 weeks | Oriented bovine cartilage ECM-derived scaffold using thermal-induced phase separation (TIPS) technology and seeded with rabbit BMSCs: (i) cell-oriented scaffold construct; (ii) cell-random scaffold composite | (i) Paraffin embedding
(ii) H&E, Toluidine Blue, and Safranin O staining
(iii) Modified O’Driscoll score
(iv) microCT
(v) Unconfined compression test (UCC) on fresh samples: Young’s modulus
(v) Quantification of total DNA level, total GAG, and collagen content | Similar trends among histomorphological score, DNA, GAG, and collagen content and biomechanics | Jia et al. [37] |
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| Fifty-two Japanese white rabbits (6 months old) | Defects in the trochlea (4.3 mm Ø and 7 mm depth) for 1, 2, 4, and 12 weeks | Hydroxyapatite- (Hap-) coated double-network (DN) hydrogel (HAp/DN gel) | (i) MMA embedding (sagittal cut)
(ii) Villanueva bone staining
(iii) IHC: procollagen 1A1
(iv) Pushout test
(v) MicroCT: Bonding area and tissue density | Similar trend between microCT and biomechanics | Wada et al. [38] |
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| Five female Japanese white rabbits (6 months old) | Defects in the trochlea (4.7 mm Ø and 7 mm depth) for 1 month | (i) Collagen fibril-based tough hydrogels based on the double network (DN) concept using swim bladder collagen (SBC) extracted from Bester sturgeon fish (SBC/PDMAAm)
(ii) Hydroxyapatite- (Hap-) coated gel (HAp/c-SBC(ge-1)/PDMAAm) | (i) Pushout and compression test on fresh samples | Significant differences in biomechanical performance | Mredha et al. [39] |
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| Forty-eight adult male NZW rabbits | Defects in the medial femoral condyles (4 mm Ø and 5 mm depth) for 1, 2, and 4 months | Porous tantalum (PT) loaded with BMP-7 (MPT group) | (i) SEM analysis
(ii) MMA embedding (longitudinal cut)
(iii) Toluidine Blue staining
(iv) MicroCT (at 16 weeks): bone intertrabecular space (trabecular spacing, Tb. Sp); bone density; Tb.Th.; Tb.N.; BV/TV;
(v) Launch test | Similar trend among histological grading system, micro CT, and biomechanics | Wang et al. [40] |
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| Thirty-six skeletal mature NZW rabbits (5-6 months old) | Defects in the central medial femoral condyle (4 mm Ø and 5 mm depth) for 4 months | Bilayered PLGA/PLGA-Hap composite scaffold preseeded with BMSCs | (i) Paraffin embedding (longitudinal cut)
(ii) H&E, Toluidine Blue, and Safranin O stainings
(iii) IHC: Col II
(iv) MicroCT on fresh samples
(v) AFM test of Young’s modulus and surface roughness
(vi) Western blot: p-smad 1, p-smad 2, and Col I and II | Significant differences in protein expression but not in all other parameters | Xiangyu et al. [41] |
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| Forty-two NZW rabbits (6–12 months old) | Defects in the trochlea (5 mm Ø and 5 mm depth) for 6 months | (i) Osteochondral allografts (OCA) stored in Tsmu
(ii) OCA after vitrification | (i) Paraffin embedding
(ii) Mankin score
(iii) H&E, Safranin O/fast green staining
(iv) Quantification of chondrocyte viability (fluorescein diacetate and ethidium bromide staining), proteoglycan (PG) type II collagen
(v) Compression test on fresh samples: Young’s modulus | Similar trends among gross score, chondrocyte viability, PG content, type II collagen, and Young’s modulus | Cao et al. [42] |
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