Osteoarthritis is a global problem and the treatment of early disease is a clear area of unmet clinical need. Treatment strategies include cell therapies utilising chondrocytes e.g. autologous chondrocyte implantation and mesenchymal stem/stromal cells (MSCs) e.g. microfracture. The result of repair is often considered suboptimal as the goal of treatment is a more accurate regeneration of the tissue, hyaline cartilage, which requires a more detailed understanding of relevant biological signalling pathways. In this study, we describe a modulator of regulatory pathways common to both chondrocytes and MSCs. The chondrocytes thought to be cartilage progenitors are reported to reside in the superficial zone of articular cartilage and are considered to have the same developmental origin as MSCs present in the synovium. They are relevant to cartilage homeostasis and, like MSCs, are increasingly identified as candidates for joint repair and regenerative cell therapy. Both chondrocytes and MSCs can be regulated by the Wnt and TGFβ pathways. Dishevelled Binding Antagonist of Beta-Catenin (Dact) family of proteins is an important modulator of Wnt and TGFβ pathways. These pathways are key to MSC and chondrocyte function but, to our knowledge, the role of DACT protein has not been studied in these cells. DACT1 and DACT2 were localised by immunohistochemistry in the developing joints of mouse embryos and in adult human cartilage obtained from knee replacement. RNAi of DACT1 and DACT2 was performed on isolated chondrocytes and MSCs from human bone marrow. Knockdown efficiency and cell morphology was confirmed by qPCR and immunofluorescence. To understand which pathways are affected by DACT1, we performed next-generation sequencing gene expression analysis (RNAseq) on cells where DACT1 had been reduced by RNAi. Top statistically significant (p < 0 .05) 200 up and downregulated genes were analysed with Ingenuity® Pathway Analysis software. We observed DACT1 and DACT2 in chondrocytes throughout the osteoarthritic tissue, including in chondrocytes forming cell clusters. On the non-weight bearing and visually undamaged cartilage, DACT1 and DACT2 was localised to the articular surface. Furthermore, in mouse embryos (E.15.5), we observed DACT2 at the interzones, sites of developing synovial joints, suggesting that DACT2 has a role in cartilage progenitor cells. We subsequently analysed the expression of DACT1 and DACT2 in MSCs and found that both are expressed in synovial and bone marrow-derived MSCs. We then performed an RNAi knockdown experiment. DACT1 knockdown in both chondrocyte and MSCs caused the cells to undergo apoptosis within 24 hours. The RNA-seq study of DACT1 silenced bone marrow-derived MSCs, from 4 different human subjects, showed that loss of DACT1 has an effect on the expression of genes involved in both TGFβ and Wnt pathways and putative link to relevant cell regulatory pathways. In summary, we describe for the first time, the presence and biological relevance of DACT1 and DACT2 in chondrocytes and MSCs. Loss of DACT1 induced cell death in both chondrocytes and MSCs, with RNA-seq analysis revealing a direct impact on transcript levels of genes involved in the Wnt and TFGβ signalling, key regulatory pathways in skeletal development and repair

Purpose. We report on minimum 2 year follow-up results of 71 patients randomised to autologous chondrocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) for the treatment of osteochondral defects of the knee. Introduction. ACI is used widely as a treatment for symptomatic chondral and osteochondral defects of the knee. Variations of the original periosteum-cover technique include the use of porcine-derived type I/type III collagen as a cover (ACI-C) and matrix-induced autologous chondrocyte implantation (MACI) using a collagen bilayer seeded with chondrocytes. Results. 71 patients with a mean age of 33 years (15-48) were randomised to undergo either an ACI-C or a MACI. 37 had ACI-C and 34 MACI. The mean size of the defect was 5.0cm2. Mean duration of symptoms was 104.4 months (9-456). Mean follow-up was 33.5 months (24-45). Functional assessment using the modified Cincinnati knee score, the Bentley functional rating score and the visual analogue score was carried out. Assessment using the modified Cincinnati knee score showed a good to excellent result in 57.1% of patients followed up at 2 years, and 65.2% at 3 years in the ACI-C group; and 63.6% of patients at 2 years, and 64% at 3 years in the MACI group. Arthroscopic assessments showed a good to excellent International Cartilage Repair Society score in 81.8% of ACI-C grafts and 50% of MACI grafts. Hyaline-like cartilage or hyaline-like cartilage with fibrocartilage was found in biopsies of 56.3% of the ACI-C grafts and 30% of the MACI grafts after 2 years. Conclusion. At this stage of the trial we conclude that the clinical, arthroscopic and histological outcomes are comparable for both ACI-C and MACI

Introduction:. Unicompartmental knee arthroplasty (UKA) has been used in the past decades to treat progressive cartilage degeneration in a single compartment. Concern has been raised over the rate of revision procedures for polyethylene wear and osteoarthritic progression into the adjacent compartment. Few studies have examined the pathology of cartilage degeneration in the setting of UKA. This study aims to investigate the viability of knee chondrocytes introduced to high and low concentrations of orthopaedic wear debris particulate. Methods:. Normal human articular chondrocytes (nHAC-Kn) were expanded in DMEM/F12 containing 10% FBS, 1% Penicillin/Streptomycin (Pen/Strp), and 50 μg/mL ascorbic acid (Asc). 24 hours prior to the start of the experiment, cells were seeded on 96-well plates at a density of 3500 cells/cm. 2. and exposed to DMEM/F12 containing 5% FBS, 1% Pen/Strp, and 50 μg/mL Asc. Particles (equivalent circle diameter range: 0.2–7 μm) at a low dose of 100: 1 (particles: cells) and high dose 1000: 1 (particles: cells) were introduced to treatment wells (n = 6). Control wells (n = 6) contained particles with no cells. Treatment groups included high and low doses of TiAl. 6. V. 4. alloy, 316L Stainless Steel, and Co-Cr-Mo alloy. At days 1, 3, 5, and 7, cells were assayed with a 3-(4,5-Dimethylthiazol-2-yl)-2,5-dyphenyltetrazolium bromide (MTT) assay for determination of cell viability. Light microscopy was performed at each timepoint to assess change in cell morphology. Results:. All groups displayed a minor decrease in cell viability after 24 hours of exposure to particles. Similarly, a second distinct decrease in viability occurred at the day 3 timepoint. Days 5 and 7 yielded little change in cell viability. Results are displayed in Figure 1. Observations of light microscopy revealed cells may actively engulf particles over time. Images show particle concentrations at the same locations as chondrocytes with few particles present between cells. Conclusions:. Wear debris has been implicated as a contributing source to osteolysis and component loosening. A potential effect on the cellular level can ultimate lead to effects on the entire tissue and complications on the clinical level. A decrease in chondrocyte viability has been shown in response to the presence of particulate wear debris. Our results showed decreases in cell viability were most noticeable between 24 and 72 hours after introduction to particles. Chondrocyte death may contribute to progression of cartilage degeneration into healthy compartments of the knee. Continued experiments are underway further characterizing chondrocyte response to wear debris particulate with respect to protein and gene expression in an extended 7 day in vitro culture

Over recent years chondrocyte implantation (MACI) has become a recognised procedure. This paper presents the results of two players in the national rugby league competition who play first grade football and have undergone the procedure. Professional sports medical care can be difficult. Demands from players, the public and coaches are beyond our normal requirements as surgeons. Faced with two high-profile players with career ending focal grade 4 chondral lessions and not responding to our normal treatment methods, I performed chondrocyte implantation (MACI) to deal with this. Both players have responded well to treatment and returned to first grade football. The two players in question had focal grade 4 chondral lesions. They had not responded to treatment and had recurrent effusions restricting their ability to play. Player A required a revision acl reconstruction as he was to be away from the game for a year. I treated his chondral lesion with MACI. His effusion settled and he returned to play with no further delays other than those expected from the acl surgery. Encouraged by this result, I performed the second procedure on a very high- profile player who had recurrent pain and effusion and had been treated with arthroscopies with little improvement. Faced with retirement, he opted for the procedure and returned to first grade the following season

Introduction. Matrix metalloproteinases (MMP) play a key role in cartilage degradation in osteoarthritis. Statins are a potential suppressor of MMPs. The aim of this research was to assess the efficacy of Pravastatin in suppressing MMP gene and protein expression in an in vitro model. Methods. We stimulated normal human chondrocytes with IL-1b for 6 hours to induce MMP expression and then treated with Pravastatin (1, 5 & 10 mM) for a further 18 hours. Cells stimulated with IL-1b but not treated with Pravastatin served as controls. Real-time PCR was used to assess expression of MMP-3 and MMP-9 mRNA. MMP enzyme activity was assessed using a fluorescent MMP-specific substrate. Staistical analysis was performed using ANOVA. Results. MMP-3 and -9 mRNA expression was reduced at all concentrations tested with a statistically significant trends in reduction (p=0.002 and < 0.001 respectively). Analaysis of culture supernatants revealed that Pravastatin treatment led to a reduction in total MMP activity but not to a statistically significant degree (p=0.07). Conclusion. We conclude that treatment with Pravastatin of stimulated human chondrocytes leads to a down regulation of selected MMP genes and a reduction in MMP enzyme activity. Our results are further evidence that statins may have a role to play in the treatment of osteoarthritis and other disorders of cartilage degradation

This study investigated confocal laser scanning microscopy (CLSM) as a novel method of imaging of chondrocytes on a collagen membrane used for articular cartilage repair. Cell viability and the effects of surgery on the cells were assessed. Cell images were acquired under four conditions: 1, Pre-operative 2, After handling 3, Heavily grasped with forceps 4, Cut around the edge. Live and dead cell stains were used. Images were obtained for cell counting and morphology. Mean cell density was 1.12–1.68 ± 0.22 × 10. 6. cells/cm. 2. in specimens without significant trauma (n=25 images), this decreased to 0.253 × 10. 6. cells/cm. 2. in the specimens that had been grasped with forceps (p <0.001) (5 images). Cell viability on delivery grade membrane was 86.8±2.1%. The viability dropped to 76.3 ± 1.6% after handling and 35.1 ± 1.7% after crushing with forceps. Where the membrane was cut with scissors, there was a band of cell death where the viability dropped to 17.3 ± 2.0% compared to 73.4 ± 1.9% in the adjacent area (p <0.001). Higher magnification revealed cells did not have the rounded appearance of chondrocytes. CLSM can quantify and image the fine morphology of cells on a MACI membrane. Careful handling of the membrane is essential to minimise chondrocyte death during surgery

The technique of Matrix Induced Autologous Chondrocyte Transplantation (MACI) is well established with satisfactory outcomes up to five years in the knee. Fewer series describe the outcomes of this technique in the ankle. We present the functional outcomes of the technique for a single surgeon series in a general hospital setting. Twenty-seven patients, mean age 41, were reviewed at 3.7 (range, 1 to 5) years. Patients were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) hind-foot scale, Tegener activity score and University of California lower extremity activity scale. MRI findings were also reviewed. While most patients report a significant improvement in symptoms with full return to activities of daily living, 36% of those under 40 and 78% of those over 40 reported restricted recreational activity. Of the patients under 40 years of age, 86% were able to run compared with 23% of those over 40. Of patients over 40, 64% continued to have moderate or severe pain. Careful preoperative counselling is required for patients of all ages regarding likely outcomes. In patients over 40 the procedure is unlikely to give good pain relief and alternative options should be considered

The treatment of osteochondral lesions in the ankle joint remains a challenging problem. While debridement and drilling or microfracture of the lesion reduce symptoms initially, long-term stability of the fibrous repair tissue is questionable. Osteochondral transplantation or mosaicplasty provide hyaline cartilage and repair the bony defect at the same time. However, an open arthrotomy with medial, lateral or anterior osteotomy is necessary to repair lesions of the talus. Lesions of the distal tibia cannot be reached. Matrix Associated Chondrocyte Implantation (MACI) has been shown to produce hyaline like cartilage repair tissue, and the implantation can be performed arthroscopically. Long term follow up studies (up to 10 years) in the knee demonstrate promising results. The purpose of this study was to assess the efficacy of arthroscopic MACI for the treatment of osteochondral lesions in the ankle joint. We reviewed all patients (n=20) who had arthroscopic MACI treatment (n=22) between February 2006 and November 2008 clinically (Foot Function Index, AAOS Foot and Ankle Questionnaire, AOFAS-Hindfoot Score) and with MRI (3 Tesla Siemens MRI). The clinical results and MRI findings up to three years after MACI were compared to pre-operative data. Possible correlations with the individual history and the nature, size or location of the lesion will be discussed. The surgical technique will be described. The results of the procedure are promising

Introduction

We report the initial 2 and 3 year follow-up results of this randomised controlled trial of autologous chondrocyte implantation (ACI) using porcine-derived collagen membrane as a cover (ACI-C) versus matrix-carried autologous chondrocyte implantation (MACI) for the treatment of osteochondral defects of the knee.

The results for autologous chondrocyte implantation (ACI) in the treatment of osteochondral defects in the knee are encouraging. At present, two techniques have been described to retain the chondrocyte suspension within the defect. The first involves using a periosteal flap harvested from the distal femur and the second involves using a type I/III collagen membrane. To the authors' knowledge there are no comparative studies of these two techniques in the current literature. A total of 68 patients with a mean age of 30.52 years (range 15 to 52 years) with symptomatic articular cartilage defects were randomised to have either ACI with a periosteal cover (33 patients) or ACI with a type I/III collagen cover (35 patients). The mean defect size was 4.54 cm. 2. (range 1 to 12 cm. 2. ). All patients were followed up at 24 months. A functional assessment using the Modified Cincinnati score showed that 74% of patients had a good or excellent result following the ACI with collagen cover compared with 67% after the ACI with periosteum cover at 2 years (p>0.05). Arthroscopy at 1 year also demonstrated similar results for both techniques. However, 36.4% of the periosteum covered grafts required shaving for hypertrophy compared with 1 patient for the collagen covered technique. This prospective, randomised study has shown no statistical difference between the clinical outcome of ACI with a periosteal cover versus ACI with a collagen cover at 2 years. A significant number of patients who had the ACI with periosteum technique required shaving of a hypertrophied graft within the first year of surgery. We conclude that there is no advantage in using periosteum as a cover for retaining the chondrocytes within an osteochondral defect; as a result we advocate the use of an alternative cover such as a porcine-derived, type I/III collagen membrane

A new surgical hybrid technique involving the combination of autologous bone plug(s) and autologous chondrocyte implantation (AOsP-ACI) was used and evaluated as a treatment option in 15 patients for repair of large osteochondral defects in knee (N=12) and hip joints (N=3). Autologous Osplugs were used to contour the articular surface and the autologous chondrocytes were injected underneath a biological membrane covering the plug. The average size of the osteochondral defects treated was 4.5cm. 2. The average depth of the bone defect was 26mm. The patients had a significant improvement in their clinical symptoms at 12 months with significant increase in the Lysholm Score and Harris Hip Score (p = 0.031). The repaired tissue was evaluated using Magnetic Resonance Imaging, Computerised Tomography, arthroscopy, histology and immunohistochemistry (for expression of type I and II collagen). Magnetic Resonance Imaging, Computerised Tomography and histology at 12 months revealed that the bone plug became well integrated with the host bone and repair cartilage. Arthroscopic examination at 12 months revealed good lateral integration of the AOsP-ACI with the surrounding cartilage. Immunohistochemistry revealed mixed fibro-hyaline cartilage. We conclude that the hybrid AOsP-ACI technique provides a promising surgical approach for the treatment of patients with large osteochondral defects. This study highlights the use of this procedure in two different weightbearing joints and demonstrates good early results which are encouraging. The long term results need to be evaluated

To assess the clinical outcomes of patients undergoing ACI in the patellofemoral joint.

The current study aims to ascertain the outcome of ACI with simultaneous transplantation of an autologous bone plug for the restoration of osteoarticular defects in the femoral condyle of the knee (‘Osplug’ technique).

Seventeen patients (mean age of 27±7 years), twelve with Osteochondritis dissecans (OD) and five with an osteochondral defect (OCD) was treated with unicortical autologous bone graft combined with ACI (‘Osplug’ technique). Functional outcome was assessed with Lysholm scores obtained for 5 years post-operatively. The repair site was evaluated with the Oswestry Arthroscopy Score (OAS), MOCART MRI score and ICRS II histology score.

The mean defect size was 4.5±2.6 SD cm² and mean depth was 11.3±5 SD mm. A significant improvement of Lysholm score from 45 (IQR 24, range 16–79) to 77 (IQR 28, range 41–100) at 1 year (p-value 0.001) and 70 (IQR 35, range 33–91) at 5 years (p-value 0.009). The mean OAS of the repair site was 6.2 (range 0–9) at a mean of 1.3 years. The mean MOCART score was 61 ± 22SD (range 20–85) at 2.6 ± 1.8SD years. Histology demonstrated generally good integration of the repair cartilage with the underlying bone. Poor lateral integration of the bone graft on MRI and low OAS were significantly associated with a poor outcome and failure.

The Osplug technique shows significant improvement of functional outcome for up to 5 years. This is the first report describing the association of bone graft integration with functional outcome after such a procedure.

Purpose

The rate of arthroplasty or osteotomy in patients who had undergone autologous chondrocyte implantation (ACI) for osteochondral defects in the knee was determined. Furthermore, we investigated whether any radiographic evidence of osteoarthritis (OA) prior to ACI was associated with poorer outcome following surgery.

Objective

To investigate the histological and immunohistochemical characteristics of revised and failed MACI repair tissues.

Introduction

The treatment of distal femoral cartilage defects using autologous chondrocyte implantation (ACI) and matrix-guided autologous chondrocyte implantation (MACI) is become increasingly common. This prospective 7-year study reviews and compares the clinical outcome of ACI and MACI.

Introduction and Aim

The management of grade 4 articular cartilage defects of the knee is a great challenge and surgical techniques are evolving. This single surgeon series evaluated the results of articular cartilage implantation using matrix assisted autologous cartilage implantation (B Braun, Tetec, Reutlingen Germany) in 28 patients who had failed previous micro-fracture or chondroplasty.

Hypothesis

Cartilage defects pretreated with marrow stimulation techniques will have an increased failure rate. The first 321 consecutive patients treated at one institution with autologous chondrocyte implantation for full-thickness cartilage defects that reached more than two years of follow-up were evaluated by prospectively collected data. Patients were grouped based on whether they had undergone prior treatment with a marrow stimulation technique. Outcomes were classified as complete failure if more than 25% of a grafted defect area had to be removed in later procedures because of persistent symptoms.

A prospective case control study analysed clinical and radiographic results in patients operated on with the periosteum autologous chondrocyte implantation (ACI) due to cartilage lesions on the femoral condyles over 10 years ago.

31 out of the 45 patients (3 failures, 9 non-responders, 2 others) were available for a continuous clinical (Lyshom/Tegner, IKDC, KOOS) and radiographic (Kellgren-Lawrence) follow-up at 0, 2, 5, and 10 years after the ACI procedure. The patients were sub-grouped into focal cartilage lesions (FL) – 10, osteochondritis dissecans (OCD) – 12, and cartilage lesions with simultaneous ACL reconstruction (ACL) – 9 subgroups.

Lysholm, Tegner, and IKCD subjective scores revealed stable results over the period from 2 to 10 years with a significant improvement toward the pre-operative levels, but the patients had not reached their pre-injury Tegner levels. KOOS profile at 10 years was: Pain 78.6, Symptoms 78.1, Activities of daily living 82.5, Sports 56.9, and Quality of life 55.1. A 10-year IKDC knee examination classified operated knees as: 14 normal, 10 nearly normal, 5 abnormal and 2 severely abnormal. Kellgren-Lawrence scores of 2 and above were found in 10 patients (FL 5, OCD 0, and ACL 5). Seven patients in the group required an arthroscopic re-intervention (3 ACI related, 4 ACI unrelated).

ACI provided safe and stable performance of operated knees over ten years. High incidence of knee osteoarthritis in FL and ACL subgroups, and low incidence in OCD patients indicate that best long performance is expected in localised low-impact cartilage lesions of young patients.

Background

Autologous chondrocyte implantation (ACI) and mosaicplasty (MP) are two methods of repair of symptomatic articular cartilage defects in the adult knee. This study represents the only long-term comparative clinical trial of the two methods.