Large Osteochondral Defects Research Articles

Sagittal computed tomography evaluation of osteochondritis dissecans of the capitellum correlates with clinical outcomes of arthroscopic debridement in adolescent baseball players

ObjectivesTo investigate the relationship between the size and location of osteochondral defects in capitellar osteochondritis dissecans (OCD) measured on coronal and sagittal reconstructed computed tomography (CT) images and the clinical outcomes of arthroscopic debridement in adolescent baseball players. MethodsThis retrospective study investigated the clinical outcomes of arthroscopic debridement for capitellar OCD in adolescent baseball players with ≥24 months of follow-up after surgery between 2008 and 2020. On preoperative coronal CT images, medial and lateral distance (%) were used to evaluate the location of the defect. Defect size (%) was also evaluated. On preoperative sagittal CT images, superior and inferior angles (deg) were used to evaluate the location of the defect. The size of the defect was evaluated using the defect angle (deg). Outcome measures were determined using the Timmerman–Andrews score at the latest follow-up. Spearman’s rank correlation coefficient was used to examine relationships between these parameters and the Timmerman–Andrews score. Statistical significance was set at p ​< ​0.05. ResultsThirty players [mean age, 14 (range, 11–16) years] underwent arthroscopic debridement: 5 were pitchers, 7 were catchers, 13 were infielders, and 5 were outfielders. Mean follow-up duration was 26 (range, 24–66) months. The median Timmerman–Andrews score at the latest follow-up was 193 [interquartile range (IQR), 181–200] points. Inferior angle showed statistically significant positive correlations with Timmerman–Andrews score (rs ​= ​0.520, p ​< ​0.01), pain (rs ​= ​0.478, p ​< ​0.01), and sagittal arc of motion (rs ​= ​0.409, p ​= ​0.025). Defect angle showed statistically significant negative correlations with Timmerman–Andrews score (rs ​= ​−0.462, p ​= ​0.010) and flexion contracture (rs ​= ​-0.424, p ​= ​0.020). Medial distance, lateral distance, defect size, and superior angle were not correlated with the Timmerman–Andrews score or any of its subscores. ConclusionPosterior or large osteochondral defects of the humeral capitellum on preoperative sagittal CT images affected the outcomes of arthroscopic debridement for capitellar OCD in adolescent baseball players. Level of evidenceLevel V, case series.

Initial Outcomes of Single versus Multiple-Plug Osteochondral Allograft Transplantation for Osteochondral Defects of the Knee: A Matched Cohort Analysis.

Although several prior studies have described the outcomes of osteochondral allograft (OCA) transplantation for single osteochondral lesions, there is a paucity of comparative data on outcomes of single versus multiple OCA transplants. We aimed to describe the initial outcomes of single-plug versus multiple-plug knee OCA transplants at a minimum of 1 year of follow-up. We hypothesized that there would be no difference in patient-reported outcome measures (PROMs) between patients undergoing single-plug and multiple-plug OCA transplants at a minimum of 1 year of follow-up. We retrospectively reviewed the prospectively collected data of patients undergoing OCA transplantation for large (>2 cm2) osteochondral defects of the knee. Thirty patients who underwent multiple-plug (2 + ) OCA transplants (either single surface using the snowman technique or multi-surface) were 1:1 age, sex, and body mass index (BMI) matched with 30 patients who underwent single-plug OCA transplants. PROMs, including the International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscores, were obtained both preoperatively and at a minimum of 1 year postoperatively. Failure was defined as a revision OCA or conversion to unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). The cohort comprised 30 females (31 affected left knees), with an average age of 37 ± 10.3 years and median follow-up of 2.0 years (interquartile range: 1.7-2.5 years). There was a significant increase in PROMs from the preoperative to the postoperative period for the entire cohort and the single-plug versus multiple-plug subgroups (p < 0.01). There was no difference between the groups with respect to the percentage of patients who achieved the minimal clinically important difference (MCID) for each PROM (p > 0.05). There were two failures, both in the single-plug group, with a mean time to failure of 3.5 years. There was no difference in the initial outcomes between patients undergoing single-plug versus multiple-plug OCA transplant at the short-term follow-up. LEVEL OF EVIDENCE:: Level IV, case series.

Fabrication of a Biomimetic 3D Printed Scaffold for the Treatment of Large Osteochondral Defects in an Adolescent Porcine Model: Outcomes at 6 Months

Fabrication of a Biomimetic 3D Printed Scaffold for the Treatment of Large Osteochondral Defects in an Adolescent Porcine Model: Outcomes at 6 Months

Bone autograft collapse. Clinical case of the complication and clinical case of the solutions to this problem

BACKGROUND: The issue of full-thickness osteochondral defect replacement in the talus is highly relevant. Bone autografting has proven effective in treating patients with this pathology, but the method has its drawbacks. The implantation of two or more bone autografts in large osteochondral defects may result in reduced contact strength between the donor bone and the recipient’s surrounding bone, leading to the formation of cysts and autograft instability. Clinical cases description: We present two clinical cases for your consideration. In the first case, chondroplasty of the talus was performed with mosaic implantation of bone autografts. Six months later, due to instability of the bone autograft accompanied by pain, ankle joint arthrodesis was performed. Six months postoperatively, the pain score on the VAS scale decreased from 7/10 to 3/10, the AOFAS score was 74/100, and the FAAM score was 70/84. In the second clinical case, a modified mosaic chondroplasty using AMIC technology with provisional fixation of bone autografts with a pin was performed. Six months later, CT scans showed osteointegration of the bone autografts without the formation of subchondral cysts. The questionnaires also demonstrated positive dynamics: the VAS score decreased from 7/10 to 1/10, the AOFAS score improved from 70/100 to 90/100, and the FAAM score increased from 72/100 to 83/84. CONCLUSION: The leading criterion for a successful bone autograft procedure is the stability of the autograft, which is achieved through adequate graft length and secure fixation. The proposed method of provisional fixation of the bone autograft with a pin during mosaic chondroplasty is a reproducible, effective, and cost-efficient technique that ensures the stability of the bone autograft and maintains its press-fit contact with the talus.

The role of autologous bone grafting treating of large osteochondral defects at the knee-results from a matched pairs analysis of 430 individuals in the German cartilage registry (Knorpelregister DGOU)

The role of autologous bone grafting treating of large osteochondral defects at the knee-results from a matched pairs analysis of 430 individuals in the German cartilage registry (Knorpelregister DGOU)

AUTOLOGOUS OSTEOCHONDRAL TRANSPLANTATION FOR LARGE OSTEOCHONDRAL LESIONS OF THE TALUS IS A VIABLE OPTION IN AN ATHLETIC POPULATION

Autologous osteochondral transplantation (AOT) is an effective treatment for large Osteochondral Lesions of the Talus (OLT), however little is reported on an athletic population, who are likely to place higher demands on the reconstruction. The aim is to report the outcomes of large OLT (&gt;150mm2) within an athletic population. The study population was limited to professional or amateur athletes (Tegner score &gt;6) with an OLT of size 150mm2 or greater. The surgical intervention was AOT with a donor site from the lateral femoral condyle. Clinical outcomes at a minimum of 24 months included Return to Sport, VAS and FAOS Scores. In addition, graft incorporation was evaluated by MRI using MOCART scores at 12 months post-surgery. 38 athletes including 11 professional athletes were assessed. Mean follow-up was 46 months. Mean lesion size was 249mm2. 33 patients returned to sport at their previous level and one did not return to sport (mean return to play 8.2 months). Visual analogue scores improved from 4.53 pre-operatively to 0.63 post-operatively (p=0.002). FAOS Scores improved significantly in all domains (p&lt; 0.001). Two patients developed knee donor site pain, and both had three osteochondral plugs harvested. Univariant analysis demonstrated no association between pre-operative patient or lesion characteristics and ability to return to sport. However, there was a strong correlation between MOCART scores and ability to return to sport (AUC=0.89). Our study suggests that AOT is a viable option in the management of large osteochondral talar defects in an athletic population, with favourable return to sport levels, patient satisfaction, and FAOS/VAS scores. The ability to return to sport is predicated upon good graft incorporation and further research is required to optimise this technique. Our data also suggests that patients should be aware of the increased risk of developing knee donor site pain when three osteochondral plugs are harvested.

Ex vivo storage of human osteochondral allografts: Long-term analysis over 300 days using a Ringer-based solution.

Large osteochondral defects are a major challenge in orthopedics, for which osteochondral allograft (OCA) transplantation is nowadays considered as an option, especially in young patients. However, a major issue with OCA is the need for graft storage, which ensures adequate cartilage integrity over time. The aim of this study was to test how long a Ringer-based storage solution can provide good graft quality after explantation and thus meet the requirements for OCA. For this purpose, human osteochondral allografts of the knee and ankle were analyzed. Live/Dead analysis was performed and glycosaminoglycan, as well as hydroxyproline content, were measured as crucial chondrocyte integrity factors. Furthermore, biomechanical tests focusing on stress relaxation and elastic compression modulus were performed. The critical value of 70% living chondrocytes, which corresponds to a number of 300 cells/mm², was reached after an average of 16 weeks of storage. In addition, a constant cell shrinkage was observed over time. The amount of glycosaminoglycan and hydroxyroline showed a slight and constant decrease over time, but no significant differences when compared from Day 0 to the values at Weeks 40-43. Biomechanical testing also revealed no significant differences at the different time points. Therefore, the results show that the Ringer-based storage solution at 4°C is able to provide a chondrocyte survival of 70% until Week 16. This is comparable to previously published storage solutions. Therefore, the study contributes to the establishment of a Ringer-based osteochondral allograft transplantation system for countries where medium-based storage solution cannot be approved.

Fresh Osteochondral Allograft to Medial Femoral Condyle With Proximal Tibial Opening Wedge Osteotomy

Background: Contributors to knee degeneration include mechanical axis malalignment, patellar maltracking, meniscal deficiency, and tibiofemoral instability. Full-thickness osteochondral defects in young, active patients can lead to significant pain and instability. The gold standard treatment for large (&gt;2 cm2) osteochondral defects is an osteochondral allograft (OCA) which addresses the pathologic articular cartilage loss and underlying bone deficiency. While biologic failure of fresh OCAs is reported, the majority of early failures are attributed to unaddressed mechanical malalignment in the coronal plane. Proximal tibial osteotomy (PTO) corrects malalignment thereby unloading the affected medial compartment and the newly placed OCA, improving long-term survivability. Indications: OCAs are indicated for isolated osteochondral defects and lesions in active young patients. PTO is indicated for patients with varus malalignment who risk potential graft failure of the affected medial compartment. Technique Description: The articular cartilage defect is identified, and a guide pin is drilled in the center. The defect is templated and scored around the margins. A reamer is used to drill to a total depth of 7 to 8 mm. The recipient site is then dilated for graft insertion. On the donor graft, the harvest site is outlined and drilled to the proper diameter. Careful measurement is utilized to ensure graft depth measurements match the recipient site. Once sized, the graft is tapped into place obtaining an anatomic fit along its entire periphery. The osteotomy is performed by using guide pins to delineate the plane cutting the tibia. Fluoroscopy confirmed the osteotomy site and angle. A spacing plate was securely inserted with screws, with placement confirmed by fluoroscopy. Results: Fresh OCAs can restore osteochondral defects. PTO corrects malalignment and unloads the affected medial compartment, decreasing the risk of revision graft failure or total knee arthroplasty. Discussion: Clinical and biomechanical studies that compared isolated and concomitant procedures demonstrated that OCA with PTOs had significantly greater survival rates. Significant malalignment increases the risk of graft failure. It remains unclear whether concomitant osteotomy with osteoarticular allografts leads to increased complication risk; inherent risks remain associated with individual procedures. In adolescents, simultaneous corrective osteotomy along with fresh OCA may delay arthroplasty and associated ambulatory restrictions. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

The role of autologous bone grafting in matrix-associated autologous chondrocyte implantation at the knee: Results from the German Cartilage Registry (KnorpelRegister DGOU).

To investigate whether concomitant autologous bone grafting adversely affects clinical outcome and graft survival after matrix-associated autologous chondrocyte implantation (M-ACI). The present study examines registry data of patients who underwent M-ACI with or without autologous bone grafting for large-sized chondral or osteochondral defects. Propensity score matching was performed to exclude potential confounders. A total of 215 patients with similar baseline characteristics were identified. Clinical outcome was assessed at the time of surgery and at 6, 12, 24, 36 and 60 months using the Knee Injury and Osteoarthritis Outcome Score (KOOS). KOOS change, clinical response rate, KOOS subcomponents and failure rate were determined. Patients treated with M-ACI and autologous bone grafting achieved comparable clinical outcomes compared with M-ACI alone. At 24 months postoperatively, the patient-reported outcome (PRO) of patients treated with M-ACI and autologous bone grafting was even significantly better as measured by KOOS (74.9 ± 18.8 vs. 79.2 ± 15.4; p = 0.043). However, the difference did not exceed the minimal clinically important difference (MCID). In patients with M-ACI and autologous bone grafting, a greater change in KOOS relative to baseline was observed at 6 (9.3 ± 14.7 vs. 15.0 ± 14.7; p = 0.004) and 12 months (12.6 ± 17.2 vs. 17.7 ± 14.6; p = 0.035). Overall, a high clinical response rate was observed in both groups at 24 months (75.8% vs. 82.0%; p = n.s.). The estimated survival at the endpoint of reoperation for any reason was 82.1% (SD 2.8) at 8.4 years for isolated M-ACI and 88.7% (SD 2.4) at 8.2 years for M-ACI with autologous bone grafting (p = 0.039). Even in the challenging cohort of large osteochondral defects, the additional treatment with autologous bone grafting leads to remarkably good clinical outcomes in patients treated with M-ACI. In fact, they tend to benefit more from surgery, have lower revision rates and achieve clinical response rates earlier. Subchondral bone management is critical to the success of M-ACI and should be addressed in the treatment of borderline defects. Level III.

Subchondral Bone Alignment in Osteochondral Allograft Transplants for Large Oval Defects of the Medial Femoral Condyle: Comparison of Lateral versus Medial Femoral Condyle Donors.

Supply-demand mismatch of medial femoral condyle (MFC) osteochondral allografts (OCAs) remains a rate-limiting factor in the treatment of osteochondral defects of the femoral condyle. Surface contour mapping was used to determine whether a contralateral lateral femoral condyle (LFC) versus ipsilateral MFC OCA differs in the alignment of donor:native subchondral bone for large osteochondral defects of the MFC. Thirty fresh-frozen human femoral condyles were matched by tibial width into 10 groups of 3 condyles (MFC recipient, MFC donor, and LFC donor) each for 3 cartilage surgeons (90 condyles). The recipient MFC was imaged using nano-computed tomography scan. Donor oval grafts were harvested from each matched condyle and transplanted into a 17 mm × 36 mm defect created in the recipient condyle. Following the first transplant, the recipient condyle was imaged and superimposed on the native condyle nano-CT scan. The donor plug was removed and the process repeated for the other donor. Surface height deviation and circumferential step-off height deviation were compared between native and donor subchondral bone surfaces for each transplant. There was no statistically significant difference in mean subchondral bone surface deviation (LFC = 0.87 mm, MFC = 0.76 mm, P = 0.07) nor circumferential step-off height (LFC = 0.93 mm, MFC = 0.85 mm, P = 0.09) between the LFC and MFC plugs. There were no significant differences in outcomes between surgeons. There were no significant differences in subchondral bone circumferential step-off or surface deviation between ipsilateral MFC and contralateral LFC oval-shaped OCAs for 17 mm × 36 mm defects of the MFC.

Femoral head fracture with large crushed defect in weight-bearing area treated with autologous osteochondral transplantation (repositionplasty): A case report

Femoral head fracture is a rare type of fracture commonly associated with hip dislocation. Femoral head fracture treatments include conservative treatment, fragment excision, open reduction, internal fixation, and arthroplasty. In cases of young patients, open reduction and internal fixation are preferred over arthroplasty. Pipkin type 2 fractures are treated with open reduction and internal fixation in most cases because the fracture line extends upward of the fovea and includes the femoral head-acetabular weight-bearing joint surface. However, if the fracture is severely comminuted or crushed, good results are difficult to obtain with open reduction and internal fixation. A 23-years-old male patient presented to the emergency room with right hip pain after 4-m fall. In initial image work up, he was diagnosed with right posterior hip dislocation and a Pipkin type 2 femoral head fracture with an ipsilateral superior ramus fracture. After manual reduction, simple radiography and computed tomography showed reduction of the hip joint and a large osteochondral defect of approximately 6 cm2 in the weight-bearing area on the superomedial side of the femoral head. This was treated with a novel surgery named autologous osteochondral transplantation (repositionplasty), devised by the authors. The congruent reduction was confirmed by radiography and computed tomography immediately after the surgery. At 5 years postoperatively, the Harris Hip Score was 100 points and no discomfort, femoral head collapse, osteonecrosis, or traumatic arthritis were observed on follow-up radiographs. We think this method "repositionplasty" will be a good treatment method for young patients with a large defect in the weight-bearing part of the femoral head who cannot undergo open reduction and internal fixation.

Implant system for large osteochondral defects.

Issues with current treatments for osteochondral defects such as mosaicplasty and autologous chondrocyte implantation (ACI) are lack of donor material, problems associated with donor sites, necessity of second surgical intervention and cell expansion, difficult site preparation and implant fitting to match the surrounding tissue. This study presents the development of a patient specific implant system for focal osteochondral defects that addresses these issues. Using computer aided design and manufacturing techniques, computed tomography scans are utilized to design the implant and templates that facilitate site preparation to allow for precise and easy implantation of the designed perfectly fitting tissue replacement. Functionality of the system and accurate restoration of a defect is demonstrated by digital before/after comparison and with a prototype. With the presented implantation system larger defects in curved joint surfaces can be restored to an optimal shape in an easier procedure than for instance mosaicplasty. The proposed system potentially allows for later replacement of worn implants.

A novel retrograde technique for ankle osteochodral lesions: the sub-endo-chondral regenerative treatment (secret).

To describe a new surgical technique for osteochondral lesions of the ankle, using bone marrow concentrate on a scaffold and homologous bone graft positioned through a retrograde approach. Many surgical options for ankle osteochondral lesions have been described, and the ideal treatment is still debated. Bone marrow stimulating techniques are recommended for cystic lesions, with some concerns regarding the healing potential of the subchondral bone. In case of wide osteochondral defects, regenerative solutions are preferred but a massive chondral debridement is usually required. To overcome these problems, a novel technique is proposed. The proposed technique was performed on patients affected by osteochondral lesions of the talus, either cysts with intact cartilage or wide osteochondral defects. A preoperative magnetic resonance imaging was obtained to localize the lesion. A 6-mm tarsal tunnel was retrogradely created toward the lesion, to allow a complete sub-endo-chondral debridement preserving the healthy cartilage. A hyaluronan scaffold soaked with a previously prepared bone marrow concentrate was retrogradely positioned under the cartilage surface and the tunnel was filled with homologous bone graft. Preoperative clinical scores and postoperative x-rays were registered. Four patients were treated using this technique. No intraoperative and postoperative complications occurred. Good bone remodeling was observed at 12-week postoperative x-rays. This technique combines the mini-invasiveness of retrograde drilling with the regenerative properties of biological scaffold soaked with bone marrow concentrate. Despite further research being needed, it seems a new viable solution to treat both subchondral cysts and large osteochondral defects of the ankle, whose management is still controversial.

In vivo evaluation of additively manufactured multi-layered scaffold for the repair of large osteochondral defects

The repair of osteochondral defects is one of the major clinical challenges in orthopaedics. Well-established osteochondral tissue engineering methods have shown promising results for the early treatment of small defects. However, less success has been achieved for the regeneration of large defects, which is mainly due to the mechanical environment of the joint and the heterogeneous nature of the tissue. In this study, we developed a multi-layered osteochondral scaffold to match the heterogeneous nature of osteochondral tissue by harnessing additive manufacturing technologies and combining the established art laser sintering and material extrusion techniques. The developed scaffold is based on a titanium and polylactic acid matrix-reinforced collagen “sandwich” composite system. The microstructure and mechanical properties of the scaffold were examined, and its safety and efficacy in the repair of large osteochondral defects were tested in an ovine condyle model. The 12-week in vivo evaluation period revealed extensive and significantly higher bone in-growth in the multi-layered scaffold compared with the collagen–HAp scaffold, and the achieved stable mechanical fixation provided strong support to the healing of the overlying cartilage, as demonstrated by hyaline-like cartilage formation. The histological examination showed that the regenerated cartilage in the multi-layer scaffold group was superior to that formed in the control group. Chondrogenic genes such as aggrecan and collagen-II were upregulated in the scaffold and were higher than those in the control group. The findings showed the safety and efficacy of the cell-free “translation-ready” osteochondral scaffold, which has the potential to be used in a one-step surgical procedure for the treatment of large osteochondral defects.Graphic abstract

Effect of polycaprolactone scaffolds containing different weights of graphene on healing in large osteochondral defect model

Now it is possible to combine the different biomaterial properties of graphene and 3 D printing scaffolds produced by tissue engineering for cartilage repair. In the study graphene-containing (1, 3, 5, 10 wt%), porous and oriented poly-ε-caprolactone-based scaffolds were prepared by robocasting method to use in the regeneration of large osteochondral defects. The scaffolds were implanted into the full-thickness osteochondral defect in a rabbit model to evaluate the regeneration of the defect in vivo. For this purpose, twenty female New Zealand white rabbits were used and they were euthanized at 4 and 8 weeks of implantation. The reparative osteochondral tissues were harvested from rabbit distal femurs and then processed for gross appearance assessment, radiographic imaging, histopathological, histochemical and immunohistochemical examinations. Results revealed that graphene-containing graft materials caused significant amelioration at the defect areas. Graphene-containing graft materials improved the fibrous, chondroid and osseous tissue regeneration compared to the control group. The expressions of bone morphogenetic protein-2 (BMP-2), collagen-1 (col-1), vascular endothelial growth factor (VEGF) and alkaline phosphatase (ALP) expressions were more prominent in graphene-containing PCL implanted groups (p < .001). Picrosirrius red method was used for to evaluate connective and muscle tissues. Results also revealed that the ameliorative effect of graphene increased by the elevation in concentration. The most prominent healing was observed in 10 wt% graphene-containing PCL based composite scaffold implanted group. This study results showed that graphene-containing PCL scaffolds enhanced the healing significantly in large osteochondral defect areas compared to the control groups.

Mega-OATS of the knee without specialised instrumentation: a low-cost option for large cartilage defects in a resource-restrained environment

BACKGROUND: A 26-year-old patient presented to a specialised knee clinic in a public hospital with ongoing pain after having sustained a soccer injury six years prior. A large osteochondral defect of the distal medial femoral condyle was diagnosed. Due to resource limitations, fresh allograft or a large osteochondral autograft transplantation system (Mega-OATS) workbench was unavailable. CASE REPORT: A Mega-OATS cartilage transplantation was done, using the patient's posteromedial femoral condyle as donor tissue, and transplanted to the defect in the distal femoral condyle, a technique that has been well documented and followed up. At six weeks postoperatively, an MRI showed early incorporation of the graft tissue. Clinical outcomes were excellent at one year follow-up with the EQ-5D 5L score 11111, the Knee Injury and Osteoarthritis Outcome Score (KOOS-PS) 100%, and the Lysholm score also 100%. Radiographs at one year confirmed an unchanged graft position and showed no signs of osteoarthritis. DISCUSSION: Large osteochondral lesions in the knee (&gt; 4 cm2) are challenging to treat, and the most commonly used modalities are fresh osteochondral allograft (OCA) or autologous chondrocyte implantation (ACI). Mega-OATS of the knee has previously been described but is not commonly used due to the requirement of a specialised and expensive workbench, and fear of morbidity at the donor site. CONCLUSION: Mega-OATS of the knee is possible without a specialised workbench or tools and had good clinical outcomes at two-year follow-up of the patient. Level of evidence: Level 5

Functional tissue engineering of articular cartilage for biological joint resurfacing-The 2021 Elizabeth Winston Lanier Kappa Delta Award.

Biological resurfacing of entire articular surfaces represents a challenging strategy for the treatment of cartilage degeneration that occurs in osteoarthritis. Not only does this approach require anatomically sized and functional engineered cartilage, but the inflammatory environment within an arthritic joint may also inhibit chondrogenesis and induce degradation of native and engineered cartilage. Here, we present the culmination of multiple avenues of interdisciplinary research leading to the development and testing of bioartificial cartilage for tissue-engineered resurfacing of the hip joint. The work is based on a novel three-dimensional weaving technology that is infiltrated with specific bioinductive materials and/or genetically-engineered stem cells. A variety of design approaches have been tested in vitro, showing biomimetic cartilage-like properties as well as the capability for long-term tunable and inducible drug delivery. Importantly, these cartilage constructs have the potential to provide mechanical functionality immediately upon implantation, as they will need to replace a majority, if not the entire joint surface to restore function. To date, these approaches have shown excellent preclinical success in a variety of animal studies, including the resurfacing of a large osteochondral defect in the canine hip, and are now well-poised for clinical translation.

Comparing PRP and bone marrow aspirate effects on cartilage defects associated with partial meniscectomy: a confocal microscopy study on animal model.

Aim: The aim of our study was to assess the therapeutic effects of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) in an animal knee lesion complex associating a large osteochondral defect and meniscal defect resulted from partial meniscectomy, a clinical situation that occurs quite often in orthopedic practice. Materials and Methods: Twenty-one male rabbits were included in the study, and all underwent initial surgery on the right knee to create the osteochondral defect on the internal femoral condyle, and remove the anterior horn of the internal meniscus, simulating a clinical situation. Rabbits were separated in three study groups: control, PRP group, in which three PRP injections were administered, and BMAC group, in which one single BMAC injection was administered. At the end of the six months follow-up period, knees were harvested and further analyzed using confocal microscopy and three-dimensional (3D) reconstruction of the articular surface. Results: Therapeutic groups had better results concerning articular surface remodeling and joint degeneration indicators in comparison to trauma group. Conclusions: Our results suggest that using post-operative regenerative therapies does improve final results concerning surface contact remodeling that was investigated using confocal microscopy and should be considered a valid treatment adjuvant in managing patients with this type of lesion complex, as it improves global joint outcome.

Sheep condyle model evaluation of bone marrow cell concentrate combined with a scaffold for repair of large osteochondral defects.

AimsMinimally manipulated cells, such as autologous bone marrow concentrates (BMC), have been investigated in orthopaedics as both a primary therapeutic and augmentation to existing restoration procedures. However, the efficacy of BMC in combination with tissue engineering is still unclear. In this study, we aimed to determine whether the addition of BMC to an osteochondral scaffold is safe and can improve the repair of large osteochondral defects when compared to the scaffold alone.MethodsThe ovine femoral condyle model was used. Bone marrow was aspirated, concentrated, and used intraoperatively with a collagen/hydroxyapatite scaffold to fill the osteochondral defects (n = 6). Tissue regeneration was then assessed versus the scaffold-only group (n = 6). Histological staining of cartilage with alcian blue and safranin-O, changes in chondrogenic gene expression, microCT, peripheral quantitative CT (pQCT), and force-plate gait analyses were performed. Lymph nodes and blood were analyzed for safety.ResultsThe results six months postoperatively showed that there were no significant differences in bone regrowth and mineral density between BMC-treated animals and controls. A significant upregulation of messenger RNA (mRNA) for types I and II collagens in the BMC group was observed, but there were no differences in the formation of hyaline-like cartilage between the groups. A trend towards reduced sulphated glycosaminoglycans (sGAG) breakdown was detected in the BMC group but this was not statistically significant. Functional weightbearing was not affected by the inclusion of BMC.ConclusionOur results indicated that the addition of BMC to scaffold is safe and has some potentially beneficial effects on osteochondral-tissue regeneration, but not on the functional endpoint of orthopaedic interest.Cite this article: Bone Joint Res 2021;10(10):677–689.

Ultrapurified Alginate Gel Containing Bone Marrow Aspirate Concentrate Enhances Cartilage and Bone Regeneration on Osteochondral Defects in a Rabbit Model

Background: Ultrapurified alginate (UPAL) gel implantation has been demonstrated as effective in cartilage repair for osteochondral defects; however, cell transplantation within UPAL gels would be required to treat larger defects. Hypothesis: The combination of UPAL gel and bone marrow aspirate concentrate (BMAC) would enhance cartilage repair and subchondral bone repair for large osteochondral defects. Study Design: Controlled laboratory study. Methods: A total of 104 osteochondral defects (1 defect per knee) of 52 rabbits were randomly divided into 4 groups (26 defects per group): defects without any treatment (Defect group), defects treated using UPAL gel alone (UPAL group), defects treated using UPAL gel containing allogenic bone marrow mesenchymal stromal cells (UPAL-MSC group), and defects treated using UPAL gel containing BMAC (UPAL-BMAC group). At 4 and 16 weeks postoperatively, macroscopic and histologic evaluations and measurements of repaired subchondral bone volumes of reparative tissues were performed. Collagen orientation and mechanical properties of the reparative tissue were assessed at 16 weeks. Results: The defects in the UPAL-BMAC group were repaired with hyaline-like cartilage with well-organized collagen structures. The histologic scores at 4 weeks were significantly higher in the UPAL-BMAC group (16.9 ± 2.0) than in the Defect group (4.7 ± 1.9; P < .05), the UPAL group (10.0 ± 3.3; P < .05), and the UPAL-MSC group (12.2 ± 2.9; P < .05). At 16 weeks, the score in the UPAL-BMAC group (24.4 ± 1.7) was significantly higher than those in the Defect group (9.0 ± 3.7; P < .05), the UPAL group (14.2 ± 3.9; P < .05), and the UPAL-MSC group (16.3 ± 3.6; P < .05). At 4 and 16 weeks, the macroscopic evaluations were significantly superior in the UPAL-BMAC group compared with the other groups, and the values of repaired subchondral bone volumes in the UPAL-BMAC group were significantly higher than those in the Defect and UPAL groups. The mechanical properties of the reparative tissues were significantly better in the UPAL-BMAC group than in the other groups. Conclusion: The implantation of UPAL gel containing BMAC-enhanced hyaline-like cartilage repair and subchondral bone repair of osteochondral defects in a rabbit knee model. Clinical Relevance: These data support the potential clinical application of 1-step treatment for large osteochondral defects using biomaterial implantation with cell transplantation.