Tissue engineering for total meniscal substitution : Animal study in sheep model

Objective: The aim of the study was to investigate the use of a novel hyaluronic acid/polycaprolactone material for meniscal tissue engineering and to evaluate the tissue regeneration after the augmentation of the implant with expanded autologous chondrocytes. Two different surgical implantation techniques in a sheep model were evaluated. Methods: Twenty-four skeletally mature sheep were treated with total medial meniscus replacements, while two meniscectomies served as empty controls. The animals were divided into two groups: cell-free scaffold and scaffold seeded with autologous chondrocytes. Two different surgical techniques were compared: in 12 animals, the implant was sutured to the capsule and to the meniscal ligament; in the other 12 animals, also a transtibial fixation of the horns was used. The animals were euthanized after 4 months. The specimens were assessed by gross inspection and histology. Results: All implants showed excellent capsular ingrowth at the periphery. Macroscopically, no difference was observed between cell-seeded and cell-free groups. Better implant appearance and integrity was observed in the group without transosseous horns fixation. Using the latter implantation technique, lower joint degeneration was observed in the cell-seeded group with respect to cell-free implants. The histological analysis indicated cellular infiltration and vascularization throughout the implanted constructs. Cartilaginous tissue formation was significantly more frequent in the cell-seeded constructs. Conclusion: The current study supports the potential of a novel HYAFF/polycaprolactone scaffold for total meniscal substitution. Seeding of the scaffolds with autologous chondrocytes provides some benefit in the extent of fibrocartilaginous tissue repair

Platelet autologous growth factors decrease the osteochondral regeneration capability of a collagen-hydroxyapatite scaffold in a sheep model

Background: Current research aims to develop innovative approaches to improve chondral and osteochondral regeneration. The objective of this study was to investigate the regenerative potential of platelet-rich plasma (PRP) to enhance the repair process of a collagen-hydroxyapatite scaffold in osteochondral defects in a sheep model. Methods: PRP was added to a new, multi-layer gradient, nanocomposite scaffold that was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles. Twenty-four osteochondral lesions were created in sheep femoral condyles. The animals were randomised to three treatment groups: scaffold, scaffold loaded with autologous PRP, and empty defect (control). The animals were sacrificed and evaluated six months after surgery. Results: Gross evaluation and histology of the specimens showed good integration of the chondral surface in both treatment groups. Significantly better bone regeneration and cartilage surface reconstruction were observed in the group treated with the scaffold alone. Incomplete bone regeneration and irregular cartilage surface integration were observed in the group treated with the scaffold where PRP was added. In the control group, no bone and cartilage defect healing occurred; defects were filled with fibrous tissue. Quantitative macroscopic and histological score evaluations confirmed the qualitative trends observed. Conclusions: The hydroxyapatite-collagen scaffold enhanced osteochondral lesion repair, but the combination with platelet growth factors did not have an additive effect; on the contrary, PRP administration had a negative effect on the results obtained by disturbing the regenerative process. In the scaffold + PRP group, highly amorphous cartilaginous repair tissue and poorly spatially organised underlying bone tissue were found

Use of innovative biomimetic scaffold in the treatment for large osteochondral lesions of the knee

Purpose: Large osteochondral defects involve two different tissues characterized by different intrinsic healing capacity. Different techniques have been proposed to treat these lesions with results still under discussion. The aim of the study is to evaluate the clinical outcome of 19 patients treated with a type I collagen-hydroxyapatite nanostructural biomimetic osteochondral scaffold at minimum follow-up of 2 years. Methods: Twenty lesions, 19 patients were treated with this scaffold implantation. The lesions size went from 4 to 8 cm2 (mean size 5.2 \ub1 1.6 cm2). All patients were clinically evaluated using the International Repair Cartilage Society score, the Tegner Score and EQ-VAS. MRI was performed at 12 and 24 months after surgery and then every 12 months and evaluated with magnetic resonance observation of cartilage repair tissue scoring scale. Results: The IKDC subjective score improved from a mean score of 35.7 \ub1 6.3 at the baseline evaluation to 67.7 \ub1 13.4 at 12-month follow-up (p < 0.0005). A further improvement was documented from 12 to 24 months (mean score of 72.9 \ub1 12.4 at 24 months) (p < 0.0005). The IKDC objective score confirmed the results. The Tegner activity score improvement was statistically significant (p < 0.0005). The EQ-VAS showed a significant improvement from 3.15 \ub1 1.09 to 7.35 \ub1 1.14 (p < 0.0005) at 2-year follow-up. The lesion' site seems to influence the results showing a better outcome in the patients affected in the medial femoral condyle. Conclusions: The use of the MaioRegen scaffold is a good procedure for the treatment for large osteochondral defects where other classic techniques are difficult to apply. It is an open one-step surgery with promising stable results at medium follow-up. Level of evidence: IV. \ua9 2013 Springer-Verlag Berlin Heidelberg

Second generation issues in cartilage repair

In recent years, regenerative techniques, such as autologous chondrocyte implantation (ACI), have emerged as a potential therapeutic option for the treatment of chondral lesions. However, the good results reported have to be weighed against the number of problems that can be observed with traditional ACI methods. To address these problems, the so-called second generation ACI techniques have been developed. Autologous chondrocyte transplantation on a 3-dimensional matrix was introduced in clinical practice from 1998 to 1999 and results at short to medium-term follow-up are well documented for different types of scaffolds. These techniques may be used for the treatment of large chondral lesions in the young, active population and highly competitive athletes, but long-term and randomized controlled studies will be needed to confirm reliability of these procedure

Improving cell seeding efficiency through modification of fiber geometry in 3D printed scaffolds

Cell seeding on 3D scaffolds is a very delicate step in tissue engineering applications, influencing the outcome of the subsequent culture phase, and determining the results of the entire experiment. Thus, it is crucial to maximize its efficiency. To this purpose, a detailed study of the influence of the geometry of the scaffold fibers on dynamic seeding efficiency is presented. 3D printing technology was used to realize PLA porous scaffolds, formed by fibers with a non-circular cross-sectional geometry, named multilobed to highlight the presence of niches and ridges. An oscillating perfusion bioreactor was used to perform bidirectional dynamic seeding of MG63 cells. The fiber shape influences the fluid dynamic parameters of the flow, affecting values of fluid velocity and wall shear stress. The path followed by cells through the scaffold fibers is also affected and results in a larger number of adhered cells in multilobed scaffolds compared to scaffolds with standard pseudo cylindrical fibers. Geometrical and fluid dynamic features can also have an influence on the morphology of adhered cells. The obtained results suggest that the reciprocal influence of geometrical and fluid dynamic features and their combined effect on cell trajectories should be considered to improve the dynamic seeding efficiency when designing scaffold architecture

Isolated Knee Arthritis as Early and Only Symptom of Whipple’s Disease

We report a case of isolated Whipple’s disease involving the knee of a 64-year-old female patient who presented recurrent monoarthritis whose origin was not clear. Initially, the cause of the gradually invalidating symptoms was related to a meniscal lesion and a diffuse minor grade chondropathy, but pain and functional impairment suggested that more exams were needed. Biopsies were performed during arthroscopy. The histology showed highly inflammatory infiltrates with PAS staining negative for Tropheryma while PCR revealed the infection with Tropheryma whipplei. This, following the recommendation of a rheumatologist and infectious disease specialist, led to biopsies of the gastrointestinal tract and analysis of the cerebrospinal fluid that showed no other organ involvement. This confirms the scientific literature that an isolated monoarthritis without involvement of the gastrointestinal tract caused by this bacterium is rare but can occur as an early manifestation of potentially fatal systemic disease. Moreover, a review of the scientific literature showed the uncertainty about epidemiology of this rare disease, suggesting that more and specific data are required

Arthroscopic autologous osteochondral grafting for cartilage defects of the knee: Prospective study results at a minimum 7-year follow-up

BACKGROUND: Articular cartilage lesions, with their inherent limited healing potential, remain a challenging problem for orthopaedic surgeons. Various approaches have been proposed to treat these lesions; nevertheless, opinions on indications and clinical efficacy of these techniques are still controversial. PURPOSE: To evaluate the outcome of osteochondral autografts for treatment of femoral condyle cartilage lesions at a medium-to long-term follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We prospectively evaluated 30 patients (mean age, 29.3 years) with full-thickness knee chondral lesions (<2.5 cm(2)) treated with arthroscopic autologous osteochondral transplantation. Thirteen patients underwent previous surgery, while 17 patients were operated on for the first time. In 19 patients, associated procedures were performed. All patients were evaluated at 2- and 7-year follow-up. The International Cartilage Repair Society form, Tegner score, and magnetic resonance imaging were used for clinical evaluation. RESULTS: The International Cartilage Repair Society objective evaluation showed 76.7% of patients had good or excellent results at 7-year follow-up, and International Knee Documentation Committee subjective score significantly improved from preoperative (34.8) to 7-year follow-up (71.8). The Tegner evaluation showed a significant improvement after the surgery at 2- and 7-year follow-up (from 2.9 to 6.2 and 5.6, respectively); however, we noticed reduced sports activity from 2- to 7-year follow-up. Magnetic resonance imaging evaluation showed good integration of the graft in the host bone and complete maintenance of the grafted cartilage in more than 60% of cases. CONCLUSION: The results of this technique at medium- to long-term follow-up are encouraging. This arthroscopic 1-step surgery appears to be a valid solution for treatment of small, grade III to IV cartilage defects

Matrix-assisted autologous chondrocyte transplantation for the repair of cartilage defects of the knee: systematic clinical data review and study quality analysis

Background: The clinical application of the second-generation tissue-engineering approach for the treatment of cartilage lesions has been documented for different types of scaffolds, but systematic information on clinical efficacy and long-term results is not available. Purpose: To analyze and assess the quality of clinical studies on different products in the emerging field of matrix-assisted autologous chondrocyte transplantation. The secondary purpose of this review was to improve the quality assessment of studies by modifying the Coleman methodology score (CMS). Study Design: Systematic review. Methods: For this review, a literature search was performed to identify all published and unpublished clinical studies of matrix-assisted (second-generation) autologous chondrocyte transplantation using the following medical electronic databases: MEDLINE, MEDLINE preprints, EMBASE, CINAHL, Life Science Citations, and British National Library of Health, including the Cochrane Central Register of Controlled Trials (CENTRAL). The search period was January 1, 1995, to July 1, 2008. To better assess cartilage-related studies, a modification of the CMS was proposed. Results: Eighteen studies were included in the analysis, reporting on 731 patients with an average follow-up of 27.3 months (6.5-60.0 months). Of the 18 studies, 2 were randomized controlled studies, 3 were prospective comparative studies, 11 were prospective cohort studies or prospective case series, and 2 were retrospective case series. Original CMSs for these studies (55.1 +/- 1.6) were significantly higher than those of cartilage repair studies in general (43.5 +/- 1.6, P < .0001) reported in 2005. The statistical analysis indicated that the modified CMS showed higher correlations and lower variability of correlations among 3 reviewers. Conclusion: The quality of the currently available data on second-generation autologous chondrocyte transplantation is still limited by study designs. The modified CMS has demonstrated better sensitivity and reproducibility with respect to the original score, so it can be recommended for cartilage clinical studies evaluation