Subchondral Bone Defects Research Articles

Use of tricortical iliac crest allograft for augmentation of depressed lateral tibial plateau fracture: a surgical technique.

Lateral tibial plateau fractures with significant articular depression and metaphyseal comminution in the setting of osteoporosis are challenging to manage. The subchondral bone defect and capacious cancellous void after surgical elevation of the articular surface is usually filled with nonstructural graft such as autologous cancellous bone graft, allogenic cancellous bone graft, or bone graft substitutes. Reports have shown a high rate of subsidence with these grafts when patients start to bear weight and ultimately failure of the construct. Structural grafts demonstrated stronger mechanical properties and lower subsidence rates. The purpose of this note is to describe a novel surgical technique using structural tricortical iliac crest allograft for the treatment of osteoporotic depressed lateral tibia plateau fracture.

Nanoclay Reinforced Integrated Scaffold for Dual-Lineage Regeneration of Cartilage and Subchondral Bone.

Tissue engineering is theoretically considered a promising approach for repairing osteochondral defects. Nevertheless, the insufficient osseous support and integration of the cartilage layer and the subchondral bone frequently lead to the failure of osteochondral repair. Drawing from this, it was proposed that incorporating glycine-modified attapulgite (GATP) into poly(1,8-octanediol-co-citrate) (POC) scaffolds via the one-step chemical cross-linking is proposed to enhance cartilage and subchondral bone defect repair simultaneously. The effects of the GATP incorporation ratio on the physicochemical properties, chondrocyte and MC3T3-E1 behavior, and osteochondral defect repair of the POC scaffold were also evaluated. In vitro studies indicated that the POC/10% GATP scaffold improved cell proliferation and adhesion, maintained cell phenotype, and upregulated chondrogenesis and osteogenesis gene expression. Animal studies suggested that the POC/10% GATP scaffold has significant repair effects on both cartilage and subchondral bone defects. Therefore, the GATP-incorporated scaffold system with dual-lineage bioactivity showed potential application in osteochondral regeneration.

Treatment of bone-cartilage defects with dual-layer tissue-engineered scaffolds loaded with icariin and quercetin.

Over the past few decades, significant research has been conducted on tissue-engineered constructs for cartilage repair. However, there is a growing interest in addressing subchondral bone repair along with cartilage regeneration. This study focuses on a bilayer tissue engineering scaffold loaded with icariin (ICA) and quercetin (QU) for simultaneous treatment of knee joint cartilage and subchondral bone defects. The cytotoxicity of dual-layer scaffolds loaded with ICA and QU was assessed through live/dead cell staining. Subsequently, these dual-layer scaffolds loaded with ICA and QU were implanted into cartilage and subchondral bone defects in Sprague-Dawley (SD) rats. The repair effects were evaluated through macroscopic observation, computed tomography, and immunohistochemistry. After 12 weeks of implantation of dual-layer scaffolds loaded with ICA and QU into the cartilage and bone defects of SD rats, better repair effects were observed in both cartilage and bone defects compared to the blank control group. We found that the dual-layer tissue-engineered scaffold loaded with ICA and QU had excellent biocompatibility and could effectively repair articular cartilage and subchondral bone injuries, showing promising prospects for clinical applications.

Lesion Distribution in the Metacarpophalangeal and Metatarsophalangeal Region of 341 Horses Using Standing Magnetic Resonance Imaging.

Pain localised to the metacarpophalangeal (MCP) and metatarsophalangeal (MTP) region represents a frequent cause of lameness in sport horses, and standing magnetic resonance imaging (MRI) of these regions is increasingly being acquired. This multicentre retrospective study describes the ranges of abnormalities identified on standing MRI of the MCP/MTP region and compares patterns of abnormalities between forelimbs, hindlimbs and different sports disciplines. In total, 341 MRI reports were reviewed. Subchondral bone plate irregularities, condylar and proximal phalanx pathologies were frequently identified with subchondral bone defect, sclerosis and increased intensity on STIR images often described. Medial pathology was frequently identified in the forelimbs, and more lateral pathology was reported in the hindlimbs, which could potentially reflect differences in the loading patterns. Significant differences in MRI findings were found between different sports activities, with MCP/MTP bone pathology occurring more frequently in MRI reports from race and endurance horses and MCP/MTP soft tissue injuries being reported more frequently in dressage and show-jumping horses, particularly in the suspensory apparatus, including the distal sesamoidean ligaments. The findings of this study identify patterns of MCP/MTP abnormalities detected using standing MRI, with differences seen between forelimbs and hindlimbs and between different sports disciplines.

Hepatocyte growth factor and insulin-like growth factor-1 were used to repair bone-cartilage defects in bone marrow mesenchymal stem cells in a rabbit model of postmenopausal

In postmenopausal osteoporosis (PMOP), an imbalance exists in the differentiation of bone marrow mesenchymal stem cells (BMSCs), with a decrease in osteogenic differentiation and an increase in adipogenic differentiation. This imbalance leads to bone marrow adiposity, bone loss, bone fragility, and a substantial rise in fracture risk. After a patient experiences an osteochondral defect due to trauma, it struggles to heal naturally, presenting a clinical challenge for treatment. Our study delved into the abnormal differentiation of BMSCs in PMOP by conducting transcriptome sequencing on BMSCs from a PMOP model (PMOP-BMSCs) and a healthy control model (Normal-BMSCs). We identified insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) genesas significantly low-expressed protein-coding genes during the osteogenic cartilage differentiation process of PMOP-BMSCs. Due to the downregulation of its expression, it leads to the deletion of the proteins it encodes IGF-1 and HGF. In order to verify the sequencing results, the feasibility of co-culture the above two growth factors with PMOP-BMSCs to repair osteochondral defects was discussed. The findings indicated that the inclusion of elements enhanced the DNA replication activity and extracellular matrix mineralization of PMOP-BMSCs. It also promoted the construction of tissue-engineered bone in vitro and the up- regulation of Runx2, BMP4, OCN, ACAN, collagen type Ⅰ, II, and Sox9 osteochondral differentiation markers. In the rabbit model of knee osteochondral injury with PMOP, the group treated with both growth factors and PMOP-BMSCs showed superior outcomes in repairing cartilage and subchondral bone defects compared to the other groups. We suggest that the addition of HGF and IGF-1 increases the expression of osteoblast and cartilage-related genes and proteins, promoting the proliferation and differentiation of osteochondrous bone in PMOP-BMSCs. These findings could offer a novel cell therapy strategy for treating postmenopausal osteoporosis, utilizing growth factors.

Early results of the combined grafting–cementation technique for the treatment of giant cell tumors with a large subchondral bone defect: a case series

Background Giant cell tumor (GCT) is a rare, locally aggressive bone tumor. It typically affects young adults close to the joints, mainly the knee joint. The high recurrence rate, along with erosion of the subchondral bone complicates the surgical plan. Current treatment standards involve extended curettage followed by space-filling by cement or graft. We present a detailed technique using a combined technique using both bone graft and cement for reconstructing GCT-related subchondral damage. Patients and methods Eighteen patients underwent surgery from January 2018 to December 2021. The surgery involved extended curettage using a high-speed burr, and lavage using hydrogen peroxide. Placement of the graft as a subchondral shelf helps to support the articular cartilage. Bone cement was applied to fill the cavity and support the graft; internal fixation was used in large-sized lesions. Results The mean follow-up is 34.5 months. Oncologically, local recurrence was reported in one case, with a distal radius location, and no distant metastasis was reported. Functionally, 86.6% had excellent/good Musculoskeletal Tumor Society score scores. Graft union had occurred in all cases; mean union time was 12 weeks. Rehabilitation included immediate passive range of motion exercises and partial weight bearing. The pain had improved significantly in all cases. Muscle power had been temporarily affected in five cases. One patient had a wound infection, managed with antibiotics. Conclusion Treatment of GCTs is challenging. The standard treatment involves curettage and gap filling. The presence of the cement close to the articular cartilage can lead to osteoarthritis due to different modulus of elasticity. We describe this combined technique to provide support, insulation, and stability, and minimize the stresses on the articular cartilage. The results of this technique are promising and yield good functional and oncological outcomes. Further research is needed to evaluate its long-term efficacy in preventing progressive osteoarthritis.

Role of crosstalk between synovial cells and chondrocytes in osteoarthritis (Review).

Osteoarthritis (OA) is a low-grade, nonspecific inflammatory disease that affects the entire joint. This condition is characterized by synovitis, cartilage erosion, subchondral bone defects, and subpatellar fat pad damage. There is mounting evidence demonstrating the significance of crosstalk between synovitis and cartilage destruction in the development of OA. To comprehensively explore the phenotypic alterations of synovitis and cartilage destruction, it is important to elucidate the crosstalk mechanisms between chondrocytes and synovial cells. Furthermore, the updated iteration of single-cell sequencing technology reveals the interaction between chondrocyte and synovial cells. In the present review, the histological and pathological alterations between cartilage and synovium during OA progression are described, and the mode of interaction and molecular mechanisms between synovial cells and chondrocytes in OA, both of which affect the OA process mainly by altering the inflammatory environment and cellular state, are elucidated. Finally, the current OA therapeutic approaches are summarized and emerging therapeutic targets are reviewed in an attempt to provide potential insights into OA treatment.

Incorporating strontium enriched amorphous calcium phosphate granules in collagen/collagen-magnesium-hydroxyapatite osteochondral scaffolds improves subchondral bone repair

Osteochondral defect repair with a collagen/collagen-magnesium-hydroxyapatite (Col/Col-Mg-HAp) scaffold has demonstrated good clinical results. However, subchondral bone repair remained suboptimal, potentially leading to damage to the regenerated overlying neocartilage. This study aimed to improve the bone repair potential of this scaffold by incorporating newly developed strontium (Sr) ion enriched amorphous calcium phosphate (Sr-ACP) granules (100–150 μm). Sr concentration of Sr-ACP was determined with ICP-MS at 2.49 ± 0.04 wt%. Then 30 wt% ACP or Sr-ACP granules were integrated into the scaffold prototypes. The ACP or Sr-ACP granules were well embedded and distributed in the collagen matrix demonstrated by micro-CT and scanning electron microscopy/energy dispersive x-ray spectrometry. Good cytocompatibility of ACP/Sr-ACP granules and ACP/Sr-ACP enriched scaffolds was confirmed with in vitro cytotoxicity assays. An overall promising early tissue response and good biocompatibility of ACP and Sr-ACP enriched scaffolds were demonstrated in a subcutaneous mouse model. In a goat osteochondral defect model, significantly more bone was observed at 6 months with the treatment of Sr-ACP enriched scaffolds compared to scaffold-only, in particular in the weight-bearing femoral condyle subchondral bone defect. Overall, the incorporation of osteogenic Sr-ACP granules in Col/Col-Mg-HAp scaffolds showed to be a feasible and promising strategy to improve subchondral bone repair.

Bilayer osteochondral graft in rabbit xenogeneic transplantation model comprising sintered 3D-printed bioceramic and human adipose-derived stem cells laden biohydrogel

Reconstruction of severe osteochondral defects in articular cartilage and subchondral trabecular bone remains a challenging problem. The well-integrated bilayer osteochondral graft design expects to be guided the chondrogenic and osteogenic differentiation for stem cells and provides a promising solution for osteochondral tissue repair in this study. The subchondral bone scaffold approach is based on the developed finer and denser 3D β-tricalcium phosphate (β-TCP) bioceramic scaffold process, which is made using a digital light processing (DLP) technology and the novel photocurable negative thermo-responsive (NTR) bioceramic slurry. Then, the concave-top disc sintered 3D-printed bioceramic incorporates the human adipose-derived stem cells (hADSCs) laden photo-cured hybrid biohydrogel (HG + 0.5AFnSi) comprised of hyaluronic acid methacryloyl (HAMA), gelatin methacryloyl (GelMA), and 0.5% (w/v) acrylate-functionalized nano-silica (AFnSi) crosslinker. The 3D β-TCP bioceramic compartment is used to provide essential mechanical support for cartilage regeneration in the long term and slow biodegradation. However, the apparent density and compressive strength of the 3D β-TCP bioceramics can be obtained for ~ 94.8% theoretical density and 11.38 ± 1.72 MPa, respectively. In addition, the in vivo results demonstrated that the hADSC + HG + 0.5AFnSi/3D β-TCP of the bilayer osteochondral graft showed a much better osteochondral defect repair outcome in a rabbit model. The other word, the subchondral bone scaffold of 3D β-TCP bioceramic could accelerate the bone formation and integration with the adjacent host cancellous tissue at 12 weeks after surgery. And then, a thicker cartilage layer with a smooth surface and uniformly aligned chondrocytes were observed by providing enough steady mechanical support of the 3D β-TCP bioceramic scaffold.

Microdrilling Resulted in Less Subchondral Bone Destruction Than a Traditional Microfracture Awl for Articular Cartilage Defect Bone Marrow Stimulation

The purpose of this study was to compare bone marrow stimulation using micro-computed tomography (micro-CT) analysis of an abrasion arthroplasty technique, drilling k-wire technique, traditional microfacture awl, or a microdrill instrument for subchondral bone defects. Eleven cadaveric distal femoral specimens were obtained and divided into 3 common areas of osteochondral defect: trochlea and weightbearing portions of the medial and lateral femoral condyles. Each area of interest was then denuded of cartilage using a PoweRasp and divided into quadrants. Each quadrant was assigned either a 1.6 mm Kirschner wire (k-wire), 1.25 mm microfracture awl, 1.5 mm fluted microdrill, PowerPick, or a curette (abrasion arthroplasty) to create 4 channels into the subchondral bone sing the same instrument. Subchondral bone and adjacent tissue areas were then evaluated using micro-CT to analyze adjacent bone destruction and extension into the bone marrow. Overall, there was a significantly decreased area of bone destruction or compression using the microdrill (0.030 mm) as compared to the microfracture awl (0.072 mm) and k-wire (0.062 mm) (P < .05). Within the trochlea and the medial femoral condyle, there was significantly decreased bony compression with the microdrill as compared to the awl and k-wire (P < .05); however, when stratified, this was not significant among the lateral femoral condylar samples (P= .08). Bone marrow stimulation causes bony compression that may negatively impact subchondral bone and trabecular alignment. It is important to understand which tools used for bone marrow stimulation cause the least amount of damage to the subchondral bone. This study demonstrates the decreased subchondral bony defects seen with the microdrill versus the traditional microfracture awl indicating that when performing bone marrow stimulation, the microdrill may be a less harmful tool to the subchondral bone.

Poster 284: Investigating the Frequency and Extent of Articular Cartilage Injury Following Patellar Dislocation: A Comparison of Recurrent vs. First-Time Dislocations

Objectives: In cases of patellar dislocation, surgical intervention is typically reserved for patients with recurrent instability, unless a chondral or osteochondral fragment is identified following the initial dislocation. There is concern that multiple dislocation events may result in a higher incidence of articular cartilage injury. The purpose of this study is to compare the incidence of articular cartilage damage in patients with a single patellar dislocation to those with multiple patellar dislocations, and secondarily to compare the location and severity of chondral injury between the groups. Methods: Patients diagnosed with patellar dislocation were retrospectively identified by ICD-9 &amp; ICD-10 codes from 2017-2021. Inclusion criteria were patients with a documented history of patellar dislocation with an MRI of the affected knee available for review. Patients with articular cartilage injury prior to dislocation event were excluded. Medical records were reviewed to determine the number of previous patellar dislocations. Articular cartilage injury was graded using a validated system, AMADEUS (mean total Area Measurement And DEpth &amp; Underlying Structures, a scale from 0 to 100; 100 = no injury). Parametric continuous data was calculated by performing t tests. Nonparametric continuous data was calculated by performing Mann-Whitney tests. Chi-Square or Fisher’s Exact tests were used to calculate p values for categorical data. Results: After chart and imaging review, 233 patients were included: 117 with a primary dislocation and 116 with recurrent dislocations. Fifty-one (43.6%) of the primary dislocations and 68 (58.6%) of the recurrent dislocations were found to have articular cartilage injuries (p=0.068). When comparing the primary and recurrent groups, there was no difference in age, BMI, race, or laterality, but the recurrent group contained a significantly larger proportion of females (46.2% vs. 65.5%, P=0.004). There was no difference in lesion size, subchondral bone defect, presence of bone edema, or total AMADEUS score between groups (p=0.231). Subgroup analysis revealed that when cartilage damage is present, patients from the primary group had significantly more full-thickness lesions (p&lt;0.001) and lower AMADEUS scores (p=0.016). The primary group had an increased proportion of medial facet and lateral femoral condyle lesions (p=0.026). Conclusions: There is a high percentage of cartilage injury in patients with a history of primary and recurrent patellar instability, with 43.6% and 58.6% of patients respectively, showing articular cartilage injury on MRI. Chondral injury primarily affected the medial and lateral patellar facets, and the lateral femoral condyle in both the primary and recurrent dislocation groups. However, the primary group demonstrated an increased number of full thickness lesions and subchondral bone defects. There was no difference in lesion size, presence of bone edema, or total AMADEUS score between the primary and recurrent groups. [Table: see text][Table: see text]

Diagnosis and unsuccessful management of iatrogenic fungal septic arthritis caused byWickerhamomyces anomalous(formerlyCandida pelliculosa) and concurrent osteochondral lesion in Ireland

SummaryEquine septic fungal arthritis is poorly documented in the literature. There is an absence of efficacy and safety data for antifungal medications, highlighting the importance of documenting this case. A 15‐year‐old Irish sport horse gelding presented 4/5 (AAEP) left hindlimb lame 13 days after intra‐articular medication of the left tarsocrural joint with triamcinolone and hyaluronic acid. Radiography revealed an osteochondral fragment at the distal intermediate ridge of the tibia and shallow subchondral bone defect on the medial trochlear ridge. Synoviocentesis yielded a turbid sample with an elevated total nucleated cell count (49 × 109cells/L; total neutrophil count of 62.8%). Arthroscopic lavage of the tarsocrural joint (TCJ) was performed. Ceftriaxone was administered and systemic antimicrobials initiated. The fungusWickerhamomyces anomaluswas identified on culture. The horse was subsequently intensively treated with antimicrobial and antifungal medications, both systemically and intra‐articularly over the following 60 plus days. Multiple subsequent synovial cultures revealed the persistence of the fungal organism, until a negative culture on day 55. However, on day 113, a grade 5/5 lameness was present, and a further positive synovial fungal culture. Radiographs revealed a lytic lesion at the distal tibia with marked progression. The horse was euthanised on day 126.

MRI appearance of multiple displaced osteochondritis dissecans cartilage fragments in the bicipital tendon sheath of a juvenile dog

A 1-year-old Bernese Mountain dog presented with an acute onset of left thoracic limb lameness. Magnetic resonance imaging (MRI) of the left shoulder was performed, showing a subchondral bone defect in the caudomedial aspect of the humeral head. In addition, several round hypointense structures were visible in the biceps tendon sheath. A left shoulder arthroscopy was performed, which confirmed an osteochondritic lesion. Exploration of the biceps tendon sheath via a small open approach allowed retrieval of the fragments, which likely migrated from the joint. Histopathology confirmed the structures to be multiple osteochondritic fragments.

Paper 04: Differences in the Severity and Location of Patellofemoral Cartilage Damage Between Instability Patients With and Without Patella Alta

Objectives: Patellar instability is estimated to affect approximately 150 out of 100,000 adolescents between the age of 14-18 years old, a rate which is expected to increase over time. Several risk factors have been associated with patellar instability such as younger age, trochlear dysplasia and patella alta. Patella alta is defined as a superiorly-positioned patella, commonly determined using the Caton-Deschamps Index (CDI), with a ratio of 1.3 or greater indicative of patella alta. Patients with patella alta are approximately 2.5-4.0 times more likely to suffer a recurrent patellar dislocation, which is thought to be due to the changes in biomechanics seen in patella alta. Differences in chondral injury in patients with patellar instability between patella alta and patella norma has not been evaluated. Our objective was to retrospectively analyze whether preoperative cartilage damage differs in severity and location between patellar instability patients with and without patella alta. Methods: Patients with patellar instability who underwent patellar realignment surgery at a single institution with a preoperative MRI within 3 months were included. After measurement of CDI on MRI, patients were divided into patella alta (CDI&gt;1.3) and patella norma groups. To quantify cartilage defect severity, the Magnetic Resonance Imaging Score and Classification system (AMADEUS) was utilized by two sports medicine clinical fellows. The AMADEUS score characterizes cartilage defect size, defect depth, presence of subchondral bone defects, and bone marrow edema. The scale is scored 0-100 with 100 indicating no cartilage damage. In patients with multiple cartilage defects on MRI, each defect was characterized and analyzed independently. Continuous variable data were reported as means with standard deviations and categorical data reported as frequencies with percentages. The distribution of data was assessed with the Shapiro-Wilk test. Continuous data were assessed with the Student’s t test and Mann-Whitney U tests as appropriate. Categorical data were assessed with chi-squared analysis. The threshold for significance was set to p &lt; 0.05. Multivariate analysis was conducted with defect depth, bone edema, and AMADEUS score as the dependent variable. All statistical analyses were performed with R Studio (Version 3.6.3, Vienna, Austria). Results: One hundred-twenty-one patients were divided into patella alta (n=50) and patella norma (n=71). The groups did not significantly differ in sex ratio, age at MRI, body mass index (BMI), mean reported number of prior dislocations, or mean interval between first reported dislocation and date of MRI. Thirty-four (68%) of the patella alta group and 44 (62%) of the patella norma group had chondral defects ( P=0.625) with no statistically significant difference in the size of the chondral defects between the groups ( P=0.419). In both groups, chondral injuries most affected the medial patellar facet (55% in patella alta vs. 52% in patella norma), followed by the lateral facet (25% vs 18%), and lateral femoral condyle (10% vs 14%)( P=0.859). The patella alta group had a smaller proportion of patients who had full thickness defects in comparison to the patella norma group (60% vs 82%; P=0.030). The overall AMADEUS score for the patella alta group was higher (68.9 vs. 62.1; P=0.023) compared to the patella norma group, indicating superior articular cartilage status. When looking at a multivariate regression using AMADEUS score as the dependent outcome, female sex shows an increase in AMADEUS score with a beta estimate of 11.96 ( P&lt;0.001). Female sex also shows a higher probability of having no defect associated bone marrow edema (Odds ratio:6.7; P=0.010), and a higher probability of partial-thickness defect rather than full-thickness (Odds ratio:3.9; P=0.004). Age, BMI, interval between dislocation and MRI, and reported number of dislocations were not found to be associated with total AMADEUS score, probability of having defect-associated bone marrow edema, or defect depth. Conclusions: There is a high percentage of cartilage injury in patients with a history of patellar instability with over 60% of patients showing cartilage damage on MRI. Patients with normal patellar height have a higher frequency of full thickness cartilage defects and more severe injury compared to those with patella alta. The location of cartilage injury between alta and norma is similar, with most defects affecting the medial facet, lateral facet, and lateral femoral condyle in descending frequency.

In situ fabrication of an anisotropic double-layer hydrogel as a bio-scaffold for repairing articular cartilage and subchondral bone injuries.

Articular cartilage is a smooth and elastic connective tissue playing load-bearing and lubricating roles in the human body. Normal articular cartilage comprises no blood vessels, lymphatic vessels, nerves, or undifferentiated cells, so damage self-repair is very unlikely. The injuries of articular cartilage are often accompanied by damage to the subchondral bone. The subchondral bone mainly provides mechanical support for the joint, and the successful repair of articular cartilage depends on the ability of the subchondral bone to provide a suitable environment. Currently, conventional repair treatments for articular cartilage and subchondral bone defects can hardly achieve good results due to the poor self-repairing ability of the cartilage Here, we propose a bioactive injectable double-layer hydrogel to repair articular cartilage and subchondral bone. The hydrogel scaffold mimics the multilayer structure of articular cartilage and subchondral bone. Agarose was used as a common base material for the double-layer hydrogel scaffold, in which a sodium alginate (SA)/agarose layer was used for the repair of artificially produced subchondral bone defects, while a decellularized extracellular matrix (dECM)/agarose layer was used for the repair of articular cartilage defects. The double-layer hydrogel scaffold is injectable, easy to use, and can fill in the damaged area. The hydrogel scaffold is also anisotropic both chemically and structurally. Animal experiments showed that the surface of the new cartilage tissue in the double-layer hydrogel scaffold group was closest to normal articular cartilage, with a structure similar to that of hyaline cartilage and a preliminary calcified layer. Moreover, the new subchondral bone in this group exhibited many regular bone trabeculae, and the new cartilage and subchondral bone were mechanically bound without mutual intrusion and tightly integrated with the surrounding tissue. The continuous double-layer hydrogel scaffold prepared in this study mimics the multilayer structure of articular cartilage and subchondral bone and promotes the functional repair of articular cartilage and subchondral bone, favoring close integration between the newborn tissue and the original tissue.

Collagen Scaffold Application in Arthroscopic Reconstruction of Osteochondral Lesions of the Talus With Autologous Cancellous Bone Grafts.

Single-step all-arthroscopic techniques have gained popularity recently in the treatment of osteochondral lesions of the talus (OLT). Concomitant subchondral bone defects led surgeons to add autologous bone grafting to the surgical procedures. Collagen scaffolds have been used widely for stabilization of the reconstruction and regeneration of the articular surface. To compare single-step all-arthroscopic treatment of OLT consisting of debridement, microfracture, autologous bone grafting, and application of fibrin sealant in 2 patient groups: with versus without collagen scaffold. Cohort study; Level of evidence, 3. Included were 94 patients who underwent single-step all-arthroscopic treatment for OLT. Autologous bone grafting was applied to 48 patients (BG group), while autologous bone grafting plus collagen scaffold was applied to 46 patients (BG+S group). A fibrin sealant was applied to both groups. Clinical outcomes were assessed with the American Orthopaedic Foot & Ankle Society (AOFAS) score and the visual analog scale (VAS) for pain. Radiological outcomes were evaluated with the magnetic resonance observation of cartilage repair tissue score. The mean follow-up time was 69.3 ± 20.7 months. Patients in both groups showed statistically significant improvement in pre- to postoperative AOFAS and VAS scores (P < .001 for all), with no difference between groups in AOFAS and VAS score improvement. Complete healing with or without hypertrophy was achieved in 42 patients in the BG group (87.5%) and 38 patients in the BG+S group (82.6%). The treatment of bone lesions in OLT may be the ultimate goal to obtain successful outcomes, in which case using a collagen scaffold besides grafting may not affect clinical and radiological outcomes.

Enzymatically-mineralized double-network hydrogels with ultrahigh mechanical strength, toughness, and stiffness.

Background: Synthetic hydrogels are commonly mechanically weak which limits the scope of their applications. Methods: In this study, we synthesized an organic-inorganic hybrid hydrogel with ultrahigh strength, stiffness, and toughness via enzyme-induced mineralization of calcium phosphate in a double network of bacterial cellulose nanofibers and alginate-Ca2+. Results: Cellulose nanofibers formed the first rigid network via hydrogen binding and templated the deposition of calcium phosphate, while alginate-Ca2+ formed the second energy-dissipating network via ionic interaction. The two networks created a brick-mortar-like structure, in which the "tortuous fracture path" mechanism by breaking the interlaced calcium phosphate-coated bacterial cellulose nanofibers and the hysteresis by unzipping the ionic alginate-Ca2+ network made a great contribution to the mechanical properties of the hydrogels. Conclusion: The optimized hydrogel exhibited ultrahigh fracture stress of 48 MPa, Young's modulus of 1329 MPa, and fracture energy of 3013 J/m2, which are barely possessed by the reported synthetic hydrogels. Finally, the hydrogel represented potential use in subchondral bone defect repair in an ex vivo model.

Area of the plateau depression and higher age predict post-operative subsidence in split-depression lateral tibial fracture.

The aim of this study was to determine factors that affect post-operative subsidence in split-depression lateral plateau tibial fracture (OTA/AO 41B3.1) which was treated with raft construct through a locking plate. The retrospective study evaluated all split-depression lateral plateau tibial fracture cases treated with raft construct through a locking plate between 01/2015 and 04/2020 with aminimum of 12-month follow-up. Data on the patients' age, sex, time from injury to surgery, type of plate, and use of subchondral bone defect filler were retrieved from the hospital database. The measurements of total plateau area (TPA), depressed lateral plateau area (DPA), and maximal plateau depression (MPD) were performed on the patients' pre-operative CT scans. The percentage of DPA to TPA (%DPA) was calculated. Post-operative radiographs were used for the evaluation of plateau subsidence. A subsidence greater than 2mm was considered a failure. There were 41 consecutive cases of split-depression lateral plateau tibial fracture in the reviewed period. Five cases were excluded, three of them were lost to follow up, 1 patient had no pre-operative CT scan and 1 had a history of cancer. A failure was identified in 11 (31%) cases. Patients in the failure group were older (61.0 vs 50.7years, p = 0.01), and had a higher incidence of fractures extending into intercondylar eminence (100% vs 56%, p = 0.02). Multiple logistic regression identified DPA (OR = 3.6; 95%CI 1.4-9.5, p < 0.01) and age (OR = 1.2; 95%CI 1.0-1.4, p = 0.02) as predictive factors for plateau subsidence. DPA cut-off value for predicting subsidence greater than 2mm was 5.8 cm2 [Area Under the ROC Curve 0.89 (95% CI 0.74-0.97), sensitivity 91%, specificity 80%, p < 0.01)]. Age and depressed lateral plateau area (DPA) in split-depression lateral plateau tibial fracture treated with raft construct through a locking plate are risk factors for post-operative subsidence greater than 2mm.

Vascular injury of immature epiphyses impair stem cell engraftment in cartilage defects

The purpose of our study was to investigate if vascular injury in immature epiphyses affects cartilage repair outcomes of matrix-associated stem cell implants (MASI). Porcine bone marrow mesenchymal stromal stem cells (BMSCs) suspended in a fibrin glue scaffold were implanted into 24 full-thickness cartilage defects (5 mm ø) of the bilateral distal femur of six Göttingen minipigs (n = 12 defects in 6 knee joints of 3 immature pigs; age 3.5–4 months; n = 12 defects in 6 knee joints of 3 mature control pigs; age, 21–28 months). All pigs underwent magnetic resonance imaging (MRI) at 2, 4, 12 (n = 24 defects), and 24 weeks (n = 12 defects). After the last imaging study, pigs were sacrificed, joints explanted and evaluated with VEGF, H&E, van Gieson, Mallory, and Safranin O stains. Results of mature and immature cartilage groups were compared using the Wilcoxon signed-rank test. Quantitative scores for subchondral edema at 2 weeks were correlated with quantitative scores for cartilage repair (MOCART score and ICRS score) at 12 weeks as well as Pineda scores at end of the study, using linear regression analysis. On serial MRIs, mature joints demonstrated progressive healing of cartilage defects while immature joints demonstrated incomplete healing and damage of the subchondral bone. The MOCART score at 12 weeks was significantly higher for mature joints (79.583 ± 7.216) compared to immature joints (30.416 ± 10.543, p = 0.002). Immature cartilage demonstrated abundant microvessels while mature cartilage did not contain microvessels. Accordingly, cartilage defects in immature joints showed a significantly higher number of disrupted microvessels, subchondral edema, and angiogenesis compared to mature cartilage. Quantitative scores for subchondral edema at 2 weeks were negatively correlated with MOCART scores (r = − 0.861) and ICRS scores (r = − 0.901) at 12 weeks and positively correlated with Pineda scores at the end of the study (r = 0.782). Injury of epiphyseal blood vessels in immature joints leads to subchondral bone defects and limits cartilage repair after MASI.

Hyaluronic acid-based biphasic scaffold with layer-specific induction capacity for osteochondral defect regeneration

The repair of cartilage and subchondral bone defects, especially the former, remains a challenge in clinical practice. An increasing number of studies have shown that the use of biomaterials has great advantages in regulating tissue repair, with lower cost and risk than the use of cytokines or cells. However, great challenges remain because of the marked differences between cartilage and subchondral bone. Here, biphasic osteochondral scaffolds with layer-specific differentiation were designed and developed. Hyaluronic acid (HA) was used as the matrix in the upper and lower layers, and differences in physicochemical properties and biological properties between the two layers were realized by different chemical crosslinking methods. The cartilage regeneration layer exhibited stress relaxation from the HA hydrazone crosslinking dynamics. Additionally, a porous HA hydrogel with dominant elasticity was prepared for subchondral bone repair. Importantly, a 3D-printed scaffold bracket could keep close integration of two layers and provided mechanical support, aiding the long-term tissue regeneration process. The in vitro and in vivo results indicated that the HA-base bilayer scaffold consisting of a dynamic HA layer and a porous HA layer realized the simultaneous integrated regeneration of articular cartilage and subchondral bone. Such scaffolds represent potential new materials for osteochondral regeneration.