Treatment Of Osteochondral Defects Research Articles

The use of embryonic cells in the treatment of osteochondral defects of the knee: an ovine in vivo study.

the aim of this study was to determine whether local delivery of embryonic stem-like (ESL) cells into osteochondral defects in the femoral condyles of sheep would enhance regeneration of hyaline articular cartilage. male ESL cells embedded in fibrin glue were engrafted into osteochondral defects in the medial condyles (ESL-M) of the left femur in 22 ewes. An identical defect was created in the medial condyle of the contralateral stifle joint and left untreated as a control (empty defect, ED). The ewes were divided into 5 groups. Four sheep each were euthanized at 1, 2, 6, and 12 months from surgery, and 6 ewes were euthanized 24 months post-implantation. To study the effect of varying loads on the long-term regeneration process, an identical defect was also created and ESL cell engraftment performed in the lateral condyle (ESL-L) of the left stifle joint of the animals in the 12- and 24-month groups. The evaluation of regenerated tissue was performed by biomechanical, macroscopic, histological, immunohistochemical (collagen type II) and fluorescent in situ hybridization (FISH) assays. no significant differences were found between treated and control sites in the biomechanical assays at any time point. ESL cell grafts showed significantly greater macroscopic evidence of regeneration as compared to controls at 24 months after surgery; significantly better histological evidence of repair in ESL-M samples versus controls was found throughout the considered period. At 24 months from surgery there was significantly improved integration of graft edges with the host tissue in the ESL-M as compared to the ESL-L samples, demonstrating that load bearing positively affects the long-term regeneration process. ESL cells enhanced the regeneration of hyaline cartilage. FISH confirmed that the regenerative tissue originated from ESL cells. ESL cells are able to self-renew for prolonged periods without differentiation and, most importantly, to differentiate into a large variety of tissues.

Implantation of Autologous Cartilage Chips Improves Cartilage Repair Tissue Quality in Osteochondral Defects

Background: Osteochondral injuries have poor endogenous healing potential, and no standard treatment has been established. The use of combined layered autologous bone and cartilage chips for treatment of osteochondral defects has shown promising short-term clinical results. Purpose/Hypothesis: This study aimed to investigate the role of cartilage chips by comparing combined layered autologous bone and cartilage chips with autologous bone implantation alone in a Göttingen minipig model. The hypothesis was that the presence of cartilage chips would improve the quality of the repair tissue. Study Design: Controlled laboratory study. Methods: Twelve Göttingen minipigs received 2 osteochondral defects in each knee. The defects were randomized to autologous bone graft (ABG) combined with autologous cartilage chips (autologous dual-tissue transplantation [ADTT]) or ABG alone. Six animals were euthanized at 6 months and 6 animals were euthanized at 12 months. Follow-up evaluation consisted of histomorphometry, immunohistochemistry, semiquantitative scoring (International Cartilage Repair Society II), and computed tomography. Results: There was significantly more hyaline cartilage in the ADTT group (25.8%) compared with the ABG group (12.8%) at 6 months after treatment. At 12 months, the fraction of hyaline cartilage in the ABG group had significantly decreased to 4.8%, whereas the fraction of hyaline cartilage in the ADTT group was unchanged (20.1%). At 6 and 12 months, there was significantly more fibrocartilage in the ADTT group (44% and 60.8%) compared with the ABG group (24.5% and 41%). The fraction of fibrous tissue was significantly lower in the ADTT group compared with the ABG group at both 6 and 12 months. The implanted cartilage chips stained >75% positive for collagen type 4 and laminin at both 6 and 12 months. Significant differences were found in a number of International Cartilage Repair Society II subcategories. The volume of the remaining bone defect significantly decreased from 6 to 12 months in both treatment groups; however, no difference in volume was found between the groups at either 6 or 12 months. Conclusion: The presence of cartilage chips in an osteochondral defect facilitated the formation of fibrocartilage as opposed to fibrous tissue at both 6 and 12 months posttreatment. The implanted chips were present in the defect and viable after 12 months. Clinical Relevance: This study substantiates the chondrogenic role of cartilage chips in osteochondral defects.

Computed tomography analysis of osteochondral defects of the talus after arthroscopic debridement and microfracture.

PurposeThe primary surgical treatment of osteochondral defects (OCD) of the talus is arthroscopic debridement and microfracture. Healing of the subchondral bone is important because it affects cartilage repair and thus plays a role in pathogenesis of osteoarthritis. The purpose of this study was to evaluate the dimensional changes and bony healing of talar OCDs after arthroscopic debridement and microfracture.MethodsFifty-eight patients with a talar OCD were treated with arthroscopic debridement and microfracture. Computed tomography (CT) scans were obtained at baseline, 2 weeks postoperatively, and 1 year postoperatively. Three-dimensional changes and bony healing were analysed on CT scans. Additionally, clinical outcome was measured with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and numeric rating scales (NRS) for pain.ResultsAverage OCD size increased significantly (p < 0.001) in all directions from 8.6 (SD 3.6) × 6.3 (SD 2.6) × 4.8 (SD 2.3) mm (anterior–posterior × medial–lateral × depth) preoperatively to 11.3 (SD 3.4) × 7.9 (SD 2.8) × 5.8 (SD 2.3) mm 2 weeks postoperatively. At 1-year follow-up, average defect size was 8.3 (SD 4.2) × 5.7 (SD 3.0) × 3.6 (SD 2.4) mm. Only average defect depth decreased significantly (p < 0.001) from preoperative to 1 year postoperative. Fourteen of the 58 OCDs were well healed. No significant differences in the AOFAS and NRS-pain were found between the well and poorly healed OCDs.ConclusionArthroscopic debridement and microfracture of a talar OCD leads to an increased defect size on the direct postoperative CT scan but restores at 1-year follow-up. Only fourteen of the 58 OCDs were filled up completely, but no differences were found between the clinical outcomes and defect healing at 1-year follow-up.Level of evidenceIV.

Multi-layered collagen-based scaffolds for osteochondral defect repair in rabbits

IntroductionIdentification of a suitable treatment for osteochondral repair presents a major challenge due to existing limitations and an urgent clinical need remains for an off-the-shelf, low cost, one-step approach. A biomimetic approach, where the biomaterial itself encourages cellular infiltration from the underlying bone marrow and provides physical and chemical cues to direct these cells to regenerate the damaged tissue, provides a potential solution. To meet this need, a multi-layer collagen-based osteochondral defect repair scaffold has been developed in our group. AimThe objective of this study was to assess the in vivo response to this scaffold and determine its ability to direct regenerative responses in each layer in order to repair osteochondral tissue in a critical-sized defect in a rabbit knee. MethodsMulti-layer scaffolds, consisting of a bone layer composed of type I collagen (bovine source) and hydroxyapatite (HA), an intermediate layer composed of type I and type II collagen and HA; and a superficial layer composed of type I and type II collagen (porcine source) and hyaluronic acid (HyA), were implanted into critical size (3×5mm) osteochondral defects created in the medial femoral condyle of the knee joint of New Zealand white rabbits and compared to an empty control group. Repair was assessed macroscopically, histologically and using micro-CT analysis at 12weeks post implantation. ResultsAnalysis of repair tissue demonstrated an enhanced macroscopic appearance in the multi-layer scaffold group compared to the empty group. In addition, diffuse host cellular infiltration in the scaffold group resulted in tissue regeneration with a zonal organisation, with repair of the subchondral bone, formation of an overlying cartilaginous layer and evidence of an intermediate tidemark. ConclusionThese results demonstrate the potential of this biomimetic multi-layered scaffold to support and guide the host reparative response in the treatment of osteochondral defects. Statement of SignificanceOsteochondral defects, involving cartilage and the underlying subchondral bone, frequently occur in young active patients due to disease or injury. While some treatment options are available, success is limited and patients often eventually require joint replacement. To address this clinical need, a multi-layer collagen-based osteochondral defect repair scaffold designed to direct host-stem cell mediated tissue formation within each region, has been developed in our group. The present study investigates the in vivo response to this scaffold in a critical-sized defect in a rabbit knee. Results shows the scaffolds ability to guide the host reparative response leading to tissue regeneration with a zonal organisation, repair of the subchondral bone, formation of an overlying cartilaginous layer and evidence of an intermediate tidemark.

Spatially organized differentiation of mesenchymal stem cells within biphasic microparticle-incorporated high cell density osteochondral tissues.

Giving rise to both bone and cartilage during development, bone marrow-derived mesenchymal stem cells (hMSC) have the unique capacity to generate the complex tissues of the osteochondral interface. Utilizing a scaffold-free hMSC system, biphasic osteochondral constructs are incorporated with two types of growth factor-releasing microparticles to enable spatially organized differentiation. Gelatin microspheres (GM) releasing transforming growth factor-β1 (TGF-β1) combined with hMSC form the chondrogenic phase. The osteogenic phase contains hMSC only, mineral-coated hydroxyapatite microparticles (MCM), or MCM loaded with bone morphogenetic protein-2 (BMP-2), cultured in medium with or without BMP-2. After 4 weeks, TGF-β1 release from GM within the cartilage phase promotes formation of a glycosaminoglycan- and type II collagen-rich matrix, and has a local inhibitory effect on osteogenesis. In the osteogenic phase, type X collagen and osteopontin are produced in all conditions. However, calcification occurs on the outer edges of the chondrogenic phase in some constructs cultured in media containing BMP-2, and alkaline phosphatase levels are elevated, indicating that BMP-2 releasing MCM provides better control over region-specific differentiation. The production of complex, stem cell-derived osteochondral tissues via incorporated microparticles could enable earlier implantation, potentially improving outcomes in the treatment of osteochondral defects.

Combination therapy with intra-articular injection of mesenchymal stem cells and articulated joint distraction for repair of a chronic osteochondral defect in the rabbit.

The present study investigated intra-articular injection of bone-marrow-derived mesenchymal stem cells (MSCs) combined with articulated joint distraction as treatment for osteochondral defects. Large osteochondral defects were created in the weight-bearing area of the medial femoral condyle in rabbit knees. Four weeks after defect creation, rabbits were divided into six groups: control group, MSC group, distraction group, distraction + MSC group, temporary distraction group, and temporary distraction + MSC group. Groups with MSC received intra-articular injection of MSCs. Groups with distraction underwent articulated distraction arthroplasty. Groups with temporary distraction discontinued the distraction after 4 weeks. The rabbits were euthanized at 4, 8, and 12 weeks after treatment except temporary distraction groups which were euthanized at only 12 weeks. Histological scores in the distraction + MSC group were significantly better than in the control, MSC group or distraction group at 4 and 8 weeks, but showed no further improvement. At 12 weeks, the temporary distraction + MSC group showed the best results, demonstrating hyaline cartilage repair with regeneration of the osteochondral junction. In conclusion, joint distraction with intra-articular injection of MSCs promotes early cartilage repair, and compressive loading of the repair tissue after temporary distraction stimulates articular cartilage regeneration.

Biocompatibility of biomimetic multilayered alginate–chitosan/β-TCP scaffold for osteochondral tissue

Biomimetic three-layered monolithic scaffold (TLS) intended for treatment of osteochondral defects was fabricated by using freeze drying method. The multilayered material was prepared with chitosan (C) and alginate (A) polyelectrolyte complex (CA/PEC) as a cartilaginous layer, a combination of CA/PEC (60wt%) and β-tricalcium phosphate (β-TCP) (40wt%) as an intermediate layer and a combination of CA/PEC (30wt%) and β-TCP (70wt%) as a subchondral layer in order to mimic the inherent gradient structure of healthy osteochondral tissue. Characterization of the scaffolds was performed using Fourier transform infrared (FT-IR) spectroscopy analysis, swelling and scanning electron microscopy (SEM) tests. In vitro cytotoxicity assay with L929 cells and EpiDerm skin irritation test (SIT) using the EpiDerm reconstructed human epidermal (RHE) model were performed to analyze biocompatibility of the scaffolds. Characterization results showed that there were strong ionic interactions among chitosan, alginate and β-TCP and the layers showed interconnected porous structure with different swelling ratios. The relative cell viability and SIT results were greater than 70% indicating that the scaffolds are considered nontoxic according to the International Organization for Standardization (ISO) standard. All results taken together, biomimetic TLS can be considered to be suitable for osteochondral applications.

Arthroscopic Allograft Cartilage Transfer for Osteochondral Defects of the Talus

Arthroscopic treatment of osteochondral defects is well established but has had mixed results in larger lesions and revision operations. Particulated allograft cartilage transfer may provide an arthroscopic option for lesions that would otherwise have been treated through open approaches or osteotomies. The procedure is performed under noninvasive distraction with standard arthroscopic portals.

Osteogenesis and chondrogenesis of biomimetic integrated porous PVA/gel/V-n-HA/pa6 scaffolds and BMSCs construct in repair of articular osteochondral defect.

A novel bi-layered osteochondral scaffold, including of PVA/Gel/V layer for the cartilage and n-HA/PA6 layer for the subchondral bone, has been proposed to evaluate the potential of the engineered of osteochondral grafts in repairing articular osteochondral defects in rabbits. The two different layers of the scaffolds were seeded with allogenic bone marrow-derived stem cells (BMSCs), which were chondrogenically and osteogenically induced respectively. The critical-size osteochondral defects were created in the knees of adult rabbits. The defects were treated with cell-bi-layered constructs (Group A), bi-layered constructs (Group B) and untreated group C as control group. The adhesion, proliferation and differentiation of BMSCs were demonstrated by immunohistochemical staining and scanning electron microscopy (SEM) in vitro. Cell survival was tracked via fluorescent labeling in vivo. Overall, the porous PVA/Gel/V-n-HA/PA6 scaffold was compatible and had no negative effects on the BMSCs in vitro culture. The cell-bi-layered scaffolds showed superior repair results as compared to the control group using gross examination and histological assessment. With BMSCs implantation, the two different layers of the composite biomimetic scaffolds provided a suitable environment for cells to form respective tissue. Simultaneously, the RT-PCR results confirmed the expression of specific extracellular matrix (ECM) markers for cartilaginous or osteoid tissue. This investigation showed that the porous PVA/Gel/V-n-HA/PA6 scaffold is a potential matrix for treatment of osteochondral defects, and the method of using chondrogenically and osteogenically differentiated BMSCs as seed cells on each layer might be a promising strategy in repair of articular osteochondral defect due to enhanced chondrogenesis and osteogenesis.

Poor osteochondral repair by a biomimetic collagen scaffold: 1- to 3-year clinical and radiological follow-up.

Treatment of osteochondral injuries is challenging, and no gold standard has been established. Layered cell-free scaffolds are a new treatment option for these defects. The aim of this study was to evaluate the osteochondral repair in patients treated with the MaioRegen(®) scaffold, a cell-free biomimetic scaffold consisting of type I collagen and hydroxyapatite. Treatment using this scaffold has previously shown promising clinical results. Ten patients with osteochondral lesions in the knee (n=6) or in the talus (n=4) were enrolled. The patients underwent pre-operative MRI and CT scans and were assessed at 1- and 2.5-year timescales post-operatively. The cartilage and bone formations were evaluated semi-quantitatively using the MOCART score. Knee patients were clinically evaluated using KOOS, subjective IKDC and Tegner scores, whereas ankle patients were evaluated using AOFAS Hindfoot and Tegner scores. Two patients were re-operated and excluded from further follow-up due to treatment failure. None of the patients had complete regeneration of the subchondral bone evaluated using CT. At 2.5years, 6/8 patients had no or very limited (<10%) bone formation in the defects and 2/8 had 50-75% bone formation in the treated defect. MRI showed no improvement in the MOCART score at any time point. The IKDC score improved from 41.3 to 80.7, and the KOOS pain subscale improved from 63.8 to 90.8 at 2.5-year follow-up. No improvement was found with the remaining KOOS subscales, the Tegner or AOFAS Ankle-Hindfoot score. Treatment of osteochondral defects in the ankle and knee joint with a biomimetic scaffold resulted in incomplete cartilage repair and poor subchondral bone repair at 1- and 2.5-year follow-up. Clinical significant improvements were observed. These results raise serious concerns about the biological repair potential of the MaioRegen(®) scaffold, and we advise to use the MaioRegen(®) scaffold with caution. Prospective therapeutic study, Level IV.

Talar Osteochondral Defects

Abstract Intra-articular ankle injuries to the talar body is one of the common cause of athletic disability that have been estimated to occur in approximately 6.5% of the ankle sprains and commonly affect the dome of the talus. Patients are commonly referred to the clinics with an acute injury to the ankle or with chronic ankle instability. This article describes the clinical presentation and imaging to diagnose of talar osteochondral defects. The treatment options are also reviewed to give consensus on optimal treatment of this condition. Key Words: Ankle injury, imaging of osteochondral defects, osteochondral defect, talus, treatment of osteochondral defects.

Elbow arthroscopy: indications, techniques, outcomes, and complications.

Elbow arthroscopy is a tool useful for the treatment of a variety of pathologies about the elbow. The major indications for elbow arthroscopy include débridement for septic elbow arthritis, synovectomy for inflammatory arthritis, débridement for osteoarthritis, loose body extraction, contracture release, treatment of osteochondral defects and selected fractures or instability, and tennis elbow release. Contraindications, technical considerations, and favorable outcomes following treatment with elbow arthroscopy require careful patient evaluation, a thorough understanding of anatomic principles, and proper patient positioning and portal selection to guide preoperative planning and overall patient care. Elbow arthroscopy is an effective procedure for the treatment of inflammatory arthritis, osteoarthritis, and lateral epicondylitis.

Integrated trilayered silk fibroin scaffold for osteochondral differentiation of adipose-derived stem cells.

Repairing osteochondral defects (OCD) remains a formidable challenge due to the high complexity of native osteochondral tissue and the limited self-repair capability of cartilage. Osteochondral tissue engineering is a promising strategy for the treatment of OCD. In this study, we fabricated a novel integrated trilayered scaffold using silk fibroin and hydroxyapatite by combining paraffin-sphere leaching with a modified temperature gradient-guided thermal-induced phase separation (TIPS) technique. This biomimetic scaffold is characterized by three layers: a chondral layer with a longitudinally oriented microtubular structure, a bony layer with a 3D porous structure and an intermediate layer with a dense structure. Live/dead and CCK-8 tests indicated that this scaffold possesses good biocompatibility for supporting the growth, proliferation, and infiltration of adipose-derived stem cells (ADSCs). Histological and immunohistochemical stainings and real-time polymerase chain reaction (RT-PCR) confirmed that the ADSCs could be induced to differentiate toward chondrocytes or osteoblasts in vitro at chondral and bony layers in the presence of chondrogenic- or osteogenic-induced culture medium, respectively. Moreover, the intermediate layer could play an isolating role for preventing the cells within the chondral and bony layers from mixing with each other. In conclusion, the trilayered and integrated osteochondral scaffolds can effectively support cartilage and bone tissue generation in vitro and are potentially applicable for OC tissue engineering in vivo.

TruFit Plug for Repair of Osteochondral Defects-Where Is the Evidence? Systematic Review of Literature.

Objective:Treatment of osteochondral defects remains a challenge in orthopedic surgery. The TruFit plug has been investigated as a potential treatment method for osteochondral defects. This is a biphasic scaffold designed to stimulate cartilage and subchondral bone formation. The aim of this study is to investigate clinical, radiological, and histological efficacy of the TruFit plug in restoring osteochondral defects in the joint.Design:We performed a systematic search in five databases for clinical trials in which patients were treated with a TruFit plug for osteochondral defects. Studies had to report clinical, radiological, or histological outcome data. Quality of the included studies was assessed.Results:Five studies describe clinical results, all indicating improvement at follow-up of 12 months compared to preoperative status. However, two studies reporting longer follow-up show deterioration of early improvement. Radiological evaluation indicates favorable MRI findings regarding filling of the defect and incorporation with adjacent cartilage at 24 months follow-up, but conflicting evidence exists on the properties of the newly formed overlying cartilage surface. None of the included studies showed evidence for bone ingrowth. The few histological data available confirmed these results.Conclusion:There are no data available that support superiority or equality of TruFit compared to conservative treatment or mosaicplasty/microfracture. Further investigation is needed to improve synthetic biphasic implants as therapy for osteochondral lesions. Randomized controlled clinical trials comparing TruFit plugs with an established treatment method are needed before further clinical use can be supported.

Outcomes of Total Knee Arthroplasty After Osteochondral Allograft Transplantation.

Background:Fresh osteochondral allograft (OCA) transplantation is an effective treatment for osteochondral defects. Some patients require further surgical intervention, such as total knee arthroplasty (TKA). The effects of prior OCA transplantation on TKA outcomes are unknown.Purpose:This study evaluated TKA failure rates after long-term follow-up and identified factors that may have contributed to an inferior outcome. Its aims were to (1) assess if having a prior OCA transplantation would increase the surgical complications of the subsequent TKA, (2) measure the infection and failure rates following TKA, (3) ascertain subjective outcomes scores from patients with intact TKA at latest follow-up, and (4) identify potential factors that contributed to inferior outcomes.Study Design:Case series; Level of evidence, 4.Methods:A total of 35 patients who underwent TKA after OCA were identified. Pain, symptoms, function, and quality of life were evaluated using the Knee Society Function score and Knee injury and Osteoarthritis Outcome Score (KOOS). Associations between outcomes scores versus total number of surgeries before TKA were assessed using Spearman correlation. Patient characteristics (age, sex, total OCA area, presentation of osteoarthritis, and number of surgeries before TKA) were calculated between failures and nonfailures.Results:For patients with TKA surviving at latest follow-up (n = 24), mean follow-up time was 9.2 ± 4.3 years after TKA and 16.1 ± 5.2 years after OCA. While TKA after OCA did not present a technical challenge in the operating room, there was a high failure rate (31.4%). Activities of daily living, as measured on KOOS, were negatively correlated with total number of surgeries before TKA (ρ2 = –0.5, P = .041). Patient age and number of surgeries before TKA influenced the failure rate, while sex and OCA area did not appear to be factors associated with inferior outcomes.Conclusion:Patients with multiple knee operations before TKA were more likely to experience functional limitations or TKA failure. The patients who experienced TKA failure were part of a challenging subset of young patients treated with numerous orthopaedic procedures, and while these patients had inferior results with TKA after OCA, the OCA transplantation extended the time before a TKA was required without adding surgical complications.

Autologous Matrix-Induced Chondrogenesis and Generational Development of Autologous Chondrocyte Implantation

The treatment of osteochondral defects of the talus is still controversial. Matrix-guided treatment options for covering of the defect with a scaffold have gained increasing popularity. Cellular-based autologous chondrocyte implantation (ACI) has undergone a generational development overcoming the surgical drawbacks related to the use of the periosteal flap over time. As ACI is associated with high costs and limited in availability, autologous matrix-induced chondrogenesis , a single-step procedure combining microfracturing of the subchondral bone to release bone marrow mesenchymal stem cells in combination with the coverage of an acellular matrix, has gained increasing popularity. The purposes of this report are to present the arthroscopic approach of the matrix-guided autologous matrix-induced chondrogenesis technique and generational development of ACI in the treatment of chondral and osteochondral defects of the talus.

The Use of HemiCAP for the Treatment of Osteochondral Lesions

Osteochondral defects of the talus are located on the medial talar dome in most cases. Arthroscopic debridement and microfracture is the preferred primary treatment for defects up to 15 mm. The optimal secondary treatment for osteochondral defects of the talus after failed primary surgical treatment has yet to be determined. Current methods such as osteochondral autograft transfer have disadvantages including donor site morbidity. A metal resurfacing inlay implant with a diameter of 15 mm (HemiCAP) was developed for treatment of osteochondral defects of the medial talar dome. The operative approach by means of a medial malleolar osteotomy and the implantation technique is reproducible. Intra-articular contact stresses are acceptable with proper implantation, that is, recessed relative to the adjacent cartilage level. A prospective study evaluated the clinical effectiveness. Overall, 20 consecutive patients were studied for a mean period of 3 years (range: 2-5 years). There was statistically significant reduction of pain and improvement of validated ankle outcome scores and quality of life scores. One patient required a reoperation for the osteochondral defect. The promising clinical outcomes indicate that the metal implantation technique is a reasonable alternative to current secondary treatment methods for osteochondral defects of the medial talar dome after failed previous treatment.

Osteochondral transplantation for the treatment of osteochondral defects at the talus with the Diamond twin system® and graft harvesting from the posterior femoral condyles

The aim of this study is to analyze clinical results after osteochondral cylinder transplantation for osteochondral defects at the medial or lateral talar dome using the Diamond twin system (Karl Storz). We hypothesize that grafts harvesting from the posterior femoral condyles are associated with less donor site morbidity than reported by previous studies. We have surgically treated 20 patients with an osteochondral defect of the talus by osteochondral transplantation with the Diamond twin system via an osteotomy of the ankle. The osteochondral cylinders were harvested from the posterior aspects of the femoral condyles of the ipsilateral knee. The defects at donor site were filled with a bone substitute of tricalcium phosphate (Synthricer, Karl Storz). The mean age was 25.4 years. After a mean time of 12.6 months, the screws at the medial malleolus were removed and an arthroscopy was performed. The functional outcome was evaluated with the visual analog scale for pain at walking, running, stair climbing, quality of life at the time of implant removal and at a mean follow-up of 25.8 months. Activity was assessed with the Tegner scale. Knee function was evaluated with the Lysholm score. In one case, the osteochondral cylinder did not heal and an osteochondral fragment was removed arthroscopically. In all other cases, the osteochondral cylinder was stable with surrounding cartilage. The average ICRS Cartilage Repair Assessment was 10.1 points (±1.3). All malleolar osteotomies healed radiologically. In 15 patients, a synovectomy and local debridement of the ankle were performed at second-look arthroscopy. Ankle pain at walking, running and stair climbing as measured by a visual analog scale (10-0) decreased significantly from preoperatively to the first follow-up (mean 12.6 months) and to the second follow-up (mean 25.8 months). The ankle-related quality of life increased significantly from preoperatively to postoperatively. There was no significant change in the Lysholm score. The activity measured with the Tegner activity scale increased significantly from preoperatively to the last follow-up, but only two out of nine patients continued pivoting sports. Autologous osteochondral grafting with the Diamond twin system is a reliable treatment option for symptomatic osteochondral defects of the talus. After 1 year, the majority of patients had still some complaints. However, after screw removal and second-look arthroscopy, the pain and ankle-related quality of life further improved. The donor site morbidity after graft harvesting from the posterior aspects of the femoral condyles is lower than previously reported.

The Role of Erythropoietin and Bone Marrow Concentrate in the Treatment of Osteochondral Defects in Mini-Pigs

BackgroundAll available treatment options for osteochondral and chondral defects do not restore hyaline cartilage and are limited to decreasing associated pain, and maintaining or improving joint function. The purpose of this study was to evaluate the potential of erythropoietin (EPO) in combination with bone marrow aspiration concentrate (BMAC) in the treatment of osteochondral defects of mini-pigs.Methods14 Goettinger mini-pigs, in which a 6×10 mm osteochondral defect in the medial femoral condyle of both knee joints was created, were randomized into four groups: biphasic scaffold alone, scaffold with EPO, scaffold with BMAC and scaffold in combination with EPO and BMAC. After 26 weeks all animals were euthanized and histological slides were evaluated using a modified ÓDriscoll Score.ResultsIn the therapy groups, areas of chondrogenic tissue that contained collagen II were present. Adding EPO (p = 0.245) or BMAC (p = 0.099) alone to the scaffold led to a non-significant increase in the score compared to the control group. However, the combination of EPO and BMAC in the implanted scaffold showed a significant improvement (p = 0.02) in the histological score.ConclusionThe results of our study show that in mini-pigs, the combination of EPO and BMAC leads to an enhanced osteochondral healing. However, additional research is necessary to further improve the repair tissue and to define the role of MSCs and EPO in cartilage repair.

Cell-laden biphasic scaffolds with anisotropic structure for the regeneration of osteochondral tissue

Sufficient treatment of chondral and osteochondral defects to restore function of the respective tissue remains challenging in regenerative medicine. Biphasic scaffolds that mimic properties of bone and cartilage are appropriate to regenerate both tissues at the same time. The present study describes the development of biphasic, but monolithic scaffolds based on alginate, which are suitable for embedding of living cells in the chondral part. Scaffolds are fabricated under sterile and cell-compatible conditions according to the principle of diffusion-controlled, directed ionotropic gelation, which leads to the formation of channel-like, parallel aligned pores, running through the whole length of the biphasic constructs. The synthesis process leads to an anisotropic structure, as it is found in many natural tissues. The two different layers of the scaffolds are characterized by different microstructure and mechanical properties which provide a suitable environment for cells to form the respective tissue. Human chondrocytes and human mesenchymal stem cells were embedded within the chondral layer of the biphasic scaffolds during hydrogel formation and their chondrogenic (re)differentiation was successfully induced. Whereas viability of non-induced human mesenchymal stem cells decreased during culture, cell viability of human chondrocytes and chondrogenically induced human mesenchymal stem cells remained high within the scaffolds over the whole culture period of 3 weeks, demonstrating successful fabrication of cell-laden centimetre-scaled constructs for potential application in regenerative treatment of osteochondral defects. Copyright © 2014 John Wiley & Sons, Ltd.