No therapeutic strategy, administered in the early stage of osteoarthritis (OA), is fully able to block the degenerative and inflammatory progress of the pathology, whose only solution remains surgery. Aiming to identify minimally invasive therapies able to act on both degenerative and inflammatory processes, infiltrative treatments based on mesenchymal stem cells represent a promising solution due to their proliferative, immunomodulatory, anti-inflammatory, and paracrine ability. Accordingly, the aim of the present study was to investigate the performance of different cell therapies (stem cells from adipose tissue, ADSCs, stromal vascular fraction, SVF, and culture expanded, AECs vs negative control NaCl) in the treatment of OA. An in vivo model of early OA was developed in sheep knee (research protocol N.62/2018-PR date 29/01/2018 approved by the local Ethical Committee). Three and six months after the treatments injections, gross evaluation of articular surfaces (damage score, DS), histological (cartilage thickness, Th; fibrillation index, FI; collagen II content, C2) and mechanical assessment (elastic modulus, E; stress-relaxation time, τ) of cartilage were carried out. Due to the importance of the relationship between structure/composition (histology) and function (mechanics), this study investigated which of the revealed parameters were involved in such relation and how they were influenced by the level of degeneration and by the specific cell treatment, thus to better understand cell-tissue interaction.

A statistically significant multi-variable linear regression model was found between τ and Th, FI, C2 (R2 0.7, p-value 8.39E-5). The relation was particularly strong between τ and C2 (p-value 7E-4), with a positive coefficient of 0.92. This is in agreement with literature, where a higher cartilage viscosity was related to a major content of collagen. By dividing the samples in two groups depending on cartilage damage, the more degenerated group (DS > 5) showed statistically significant lower C2 (p-value 0.0124) and τ (p-value 0.05), confirming that collagen content and viscosity decrease with OA grade increasing. Averaging the entire group of samples, the OA degeneration progressed between 3 and 6 months after, and despite, the treatment. But focusing on specific treatments, SVF and AECs differed from the general trend, inducing a higher amount of collagen at 6 months respect to 3 months. Moreover, articular cartilage treated by AECs and, overall, SVF showed a higher content of collagen and a major viscosity respect to the other treatments.

We conclude that an injection of mesenchymal stem cells from stromal vascular fraction in early OA articulations could hinder the degenerative process, preserving or even restoring collagen content and viscosity of the articular cartilage.

Objectives

Matrix-assisted autologous chondrocyte transplantation (MACT) has been developed and applied in the clinical practice in the last decade to overcome most of the disadvantages of the first generation procedures. The purpose of this systematic review is to document and analyse the available literature on the results of MACT in the treatment of chondral and osteochondral lesions of the knee.

Osteocondritis dissecans (OCD) is a relatively common cause of knee pain. Ideal treatment is still controversial. Aim of this exhibit is to describe the outcomes of 5 different surgical techniques in a series of 63 patients.

63patients (age 22.5±7.4 years) affected by OCD of the femoral condyle (45 medial and 17 lateral) were treated by either osteochondral autologous transplantation, autologous chondrocyte implantation with bone graft, biomimetic nanostructured osteochondral scaffold (Maioregen) implantation, bone-cartilage paste graft or bone marrow derived cells transplantation “one-step” technique. Patient evaluation included IKDC score, eq-vas score, X-Rays and MRI preoperatively and at follow-up.

Global mean IKDC improved from pre-operative 40.1±14.6 to 77.2±21.3 (p<0.0005) at mean 5.3±4.7 years follow-up, while eq-vas improved from 51.7±17.0 to 83.5±18.3(p<0.0005). No influence of age, size of the lesion, length of follow-up and associated surgeries on the result was found. No differences were found between the results obtained with different surgeries except a slight tendency of better improvement in the result following autologous chondrocyte implantation (p<0.01). Control MRI evidenced a satisfactory repair of cartilaginous layer and subchondral bone.

The techniques described were effective in providing good clinical and radiographic results in the treatment of OCD and confirmed the validity of autologous chondrocyte implantation over time. Newer techniques such as Maioregen implantation and “one-step” base on different rationales, the first relying on the characteristics of the scaffold and the second on the regenerative potential of mesenchymal cells. Both of them have the advantages to be minimally invasive surgeries and to require a single operation.

INTRODUCTION

Osteochondral defects are still a challenge for the orthopaedic surgeon, since most of the current surgical techniques lead to fibrocartilage formation and poor subchondral regeneration, often associated to joint stiffness and/or pain.

Thinking of the ideal osteochondral graft from both the surgical an commercial point of view, it should be an off-the-shelf product; this is the research direction and the explanation for the new biomaterials recently proposed to repair osteochondral defect inducing an “in situ” cartilage regeneration starting from the time of the implantation into the defect site.

For the clinical pilot study we performed, a newly developed nanostructured biomimetic scaffold was used to treat chondral and osteochondral lesions of the knee; its safety and manageability, as much as the surgical procedure reproducibility and the clinical outcome, were evaluated in order to test its intrinsic potential without any cells colture aid.

INTRODUCTION

The menisci play a fundamental biomechanical role in the knee and also help in the maintaining of the articular homeostasis; thus, either a lesion or the complete absence of the menisci can invalidate the physiological function of the knee causing important damages, even at long term. Unfortunately, meniscal tears are often found during the ordinary orthopaedic practice while the regenerative potential of this kind of tissue is very low and limited to its peripheral-vascularized part; this is why the majority of these common arthroscopic findings are not reparable and often the surgeon is almost forced to perform a partial, subtotal or even total meniscectomy, regardless of the well-known consequences of this kind of surgery.

Objective: Meniscus regeneration is limited, moreover, loss of meniscal tissue leads to osteoarthritis. A new biomaterial, consisting of hyaluronic acid and polycaprolactone was applied as a meniscus substitute device in a study in sheep.

Methods: 24 sheep received a total medial meniscal replacement. Group SCF (n=12) was treated with a cell free scaffold, Group SCS (n=12) with a scaffold seeded with autologous chondrocytes harvested from the contralateral joints, which served as sham controls (n=12). Further 12 non-operated and 2 menisectomy controls were included in the study.

The animals were sacrificed after 4 months. The implants and joint surfaces were evaluated on a macroscopic (Implant Gross Assessment Score; Gross Assessment of Joints Score) and histological level.

Results: There was no significant difference of the Implant Gross Assessment score between the SCF and SCS groups. All implants showed excellent capsular ingrowth at the periphery. Dislocation, extrusion and tears occurred in part of the specimen due to biomechanical problems caused by soft tissue quality. The mean Gross Assessment of Joint Changes Score of the groups SCF and SCS was not statistically different. Cartilage damage was significantly more severe in joints with implants than in non-operated joints and sham controls, but less pronounced than in menisectomy controls. Histological evaluation showed residual scaffold with an associated foreign body response in all implants. Fibrous tissue was present in all implants, in contrast small foci of cartilaginous differentiation were more common in the cell-seeded constructs.

Discussion: At 4 months regenerative meniscal tissue was present but immature. The present study showed that strong biomechanical scaffold properties are a required to allow guided tissue regeneration and maturation under loading conditions. Cell seeding of the scaffold encourages cartilaginous differentiation. Modification of the scaffold and the cell-seeding technique will be investigated in further studies.

The aim of this study was to evaluate the efficacy of Hyalograft®-C, in a group of patients with full thickness patellofemoral defects.

Method: 32 patients treated with Hyalograft®-C for patellofemoral chondral lesions were evaluated. Average age was 30.5 yrs. with a mean follow-up period of 24 months. The defect area was 4.7 cm2 and the lesions were due to trauma (12 patients), malalignment (4) and osteochondritis dissecans (2). Eight patients had previous knee arthroscopy, 2 had patellar re-alignment, and 1 patient had lateral retinacular release. Subjective evaluation, ICRS-IKDC 2000 scores were used for final evaluation. Patients underwent MRI at 12 months, two patients had 2nd-look arthroscopy and biopsy. Student- T Test was used for statistical analysis.

Results: Significant improvement (p< 0.0001) with VAS scale and subjective evaluation using the ICRS scale was demonstrated. A statistically significant improvement was reported with IKDC scoring systems. MRI demonstrated almost normal cartilage in 70% of the cases with positive correlation to clinical outcomes. 2nd-look arthroscopies demonstrated good integration with the surrounding cartilage and biopsies were characterized as hyaline-like cartilage.

Conclusions: Hyalograft C is a viable option for treatment of patellofemoral cartilage lesions. Additional follow-up assessments will confirm the long-term durability of these results.

Introduction: In the last years matrix autologous chondrocyte transplantation becomes a possible solution in the treatment of chondral lesions. We develop an arthroscopic procedure for chondrocyte implant on hyaluronian-based scaffold.

Material and methods: Thirty-five patients treated using this technique achieved 3 years follow up. All the patients were clinically evaluated using IKDC score and with MRI or TC scan. In some Patients we performed a second look arthroscopy and histological evaluation.

Results: IKDC objective score improved after 12 months in all patients and the results were confirmed at 24 and 36 months of follow-up. The improving was obtained also according to IKDC subjective score. A second look arthroscopy showed healing of the defect with regenerated cartilage. The histological evaluation has demonstrated in 80% the hyaline type of new cartilage.

Conclusions: This matrix autologous chondrocyte transplantation procedure avoids the use of periosteal flap, simplify the surgical procedure and permit to perform the arthroscopic implant reducing the morbidity of the procedure. The preliminary clinical and histological results at 3 years follow-up are encouraging.

Introduction: Total meniscectomy can cause cartilage degeneration and osteoarthritis. The healing capacity of the meniscus is limited. Bioengineered meniscus can be a valid therapeutic option. Within the framework of the European Project MENISCUS, a pilot animal study was conducted to evaluate surgical technique, critical defect size, implant ingrowth and postoperative mobilization using a meniscus replacement device.

Materials and Method: Six sheep were operated on their right stifle joints. 3 sheep received a total meniscus replacement with a 3D biomaterial fixed with sutures. Additionally, controls without implant were operated. The sheep were sacrificed and evaluated clinically and histologically after 6 weeks.

Results: All implants showed excellent adhesion to the capsule and a good ingrowth at the periphery and the horns. Tissue formation was confirmed histologically.

Conclusions: Tissue ingrowth of the implant was demonstrated. The promising results concerning tissue formation and its meniscus like properties will have to be confirmed in future long-term studies.

Large bone defect repair has always presented a difficult treatment problem. Marrow-derived osteogenic progenitor cells combined with hydroxyapatite (HA) were used for segmental bone reconstruction. The validity of this model has been shown for the repair of bone defects of critical size in large animal models. We used this cell-based therapeutic approach to treat three patients with large bone defects.

The patients were 41, 22 and 16 years old and had large tibial, ulnar and humeral diaphyseal gaps that ranged in size from 3.0 to 28.3 cm³. Marrow samples were harvested from the iliac crest and osteogenic progenitors isolated and expanded “ex vivo”. The expanded cells were then combined with a highly macroporous bioceramic scaffold whose size and shape reflected each individual bony defect. The cell/bioceramic composites were implanted at the lesion sites. External fixation was used to stabilise the grafts.

At present all patients have been followed up for 4–5 years. Already after the first month after surgery an initial integration at the bone/implant interface was evident. Bone formation in the implants, assessed by X-ray, progressed steadily in the follow-up period. Two patients achieved full functional recovery at 6 months after surgery, one patient at 12 months after surgery. The present report shows that large segmental bone reconstruction can be achieved in humans using osteoprogenitor cells. This technique can be improved by a more biodegradable and more biomechanically resistant scaffold use.

Autologous chondrocyte transplantation has become a possible solution for the treatment of chondral knee lesions. Recently an autologous tissue engineered cartilage (Hyalograft C), using biodegradable scaffolds for cell proliferation, was successfully developed. In osteochondritis dissecans (OCD) the lesion also involves subchondral bone. For this reason we began to use a two-step technique: arthroscopic autologous bone grafting followed by autologouos condrocyte Hyalograft C transplantation after 4–6 months. We treated five patients affected by OCD.

All the patients were clinically evaluated and analysed according to the International Repair Cartilage Society score at 12 and 24 months. The ICRS score showed highly satisfactory clinical results in all treated patients at 12 and 24 months; CT and MRI evaluation had demonstrated a good articular surface reconstruction with complete bone defect restoration at a short 12-month follow-up period. The autologous chondrocyte transplantation provides highly satisfactory clinical results.

This second-generation autologous tissue-engineered cartilage transplantation avoids the use of periosteal flap, simplifies the surgical procedure and permits use of an arthroscopic approach. In association with autologous bone grafting, bone loss can also be restored in order to recreate a perfect articular surface. The preliminary clinical and histological results are encouraging but longer follow-up is required to better evaluate this technique.

Rotational defects of the lower limb are frequently encountered and often underestimated. In fact, many symptoms in the lower joint can be related to rotational alteration in the lower leg. These problems are often more visible in the knee joint because they reflect the rotational problems of proximal and distal femur and tibia, respectively. The extensor apparatus, due to the fact that it interacts with both bones, is the more affected joint. Many authors have demonstrated that femoral anteversion increases stress on the patello-femoral joint due to excessive lateralisation of the patella. In the same manner, distal femur internal rotation increases the stress due to altered tracking of the patella during ROM.

Valgus knee places stress on the patello-femoral joint, increasing the Q angle and determining a retraction of the lateral structure that causes stress on the lateral patellar face and altered patellar scratch during ROM. External tibial rotation also has been documented to increase the Q angle and patellar tilt, causing excessive stress on the patello-femoral joint. Valgus pronation of the foot, increasing the valgus stress on the knee, can contribute to patello-femoral symptoms, increasing the muscle imbalance at this level.

These documented alterations contribute together with other anatomical abnormalities, such as trochlear dysplasia or muscle hypoplasia, in creating the high variability of patello-femoral symptoms that are observed. Rotational deformity of the lower leg therefore represents a frequently encountered pathological condition that must be taken into account when treating patello-femoral symptoms.

A tissue engineering-based approach has become a possible solution for the treatment of chondral lesions. Actually, autologous chondrocytes seeded on biodegradable scaffolds for cell proliferation were successfully developed. However, these techniques promote cartilaginous but not bony regeneration. Therefore a new experimental approach involving mesenchymal stem cells (MSC) has been introduced.

A 31-year-old man affected by massive osteonecrosis of the right femoral head was selected to begin this study. The MSC were isolated from the bone marrow harvested from the patient’s iliac crest. After a 3-week monolayer expansion, cells were seeded and cultured onto hyaluronan-based three-dimensional scaffolds and DBM spongy chips, used to regenerate the cartilaginous and the bony portion, respectively. After a 2-week cultivation, constructs were implanted inside the osteochondral defect using the transtrochanteric approach under arthroscopic control. The patient underwent clinical, X-ray and MRI control during the first 6 months after operation.

Pluripotent MSC may be a promising strategy for osteochondral defect reconstruction due to their capacity to differentiate in vivo along chondrocytic and osteoblastic lineages. This ability, combined with two different kinds of three-dimensional scaffolds, permits simultaneous bone and cartilage tissue regeneration. The preliminary results are encouraging but a more precise judgement of the effectiveness of this method requires longer follow-up.

Valgus deformity of the knee in relation to femoral dysplasia and post-traumatic varus deformity in relation to supracondylar fracture often needs to be corrected with varus or valgus distal femoral osteotomy. This procedure must be very precise to avoid compartimental overstress. However, in valgus knee the deformity is very often not only bi-planar but also tri-planar. In fact, the rotational defect of the distal femur can play an important role in determining the clinical symptoms and in altering the pathway of patello-femoral joint.

Therefore, correcting only the valgus deformity does not solve the clinical symptoms related to incorrect rotation of distal femur. The same problem is often encountered in distal femoral deformity in relation to supracondylar fracture. The bad alignment of the healed fracture is very often on the three planes and this fact has always to be taken into account during the pre-operative planning.

The pre-operative planning is fundamental and CT of the knee joint with reference to hip and ankle must be performed to evaluate the degree of rotational deformity that must be corrected. During surgery after the correction of valgus or varus deformity is fundamental to re-check the femur rotation, because the osteotomy automatically changes also the rotation of the distal femur. However, this correction may be insufficient to correct the rotation that can maintain clinical symptoms in the patello-femoral joint. If this is the case, an additional correction in external rotation is usually necessary to achieve an overall correction of distal femoral deformity.

In our opinion, the difficulties and accuracy necessary to correct this type of pathology are often underestimated.

Autologous chondrocyte transplantation has become a possible solution for the treatment of chondral knee lesions. In the last years matrix autologous chondrocyte transplantation procedures were developed by various scientists. We selected a biodegradable, hyaluronian-based biocompatible scaffold for cell proliferation. This nonwoven three-dimensional structure consists of a network of 20 – B5-thick fibers with interstices of variable sizes which constitute an optimal physical support to allow cell-cell contacts, cluster formation, and extracellular matrix deposition in order to create a bioengenerized cartilage Hyalograft C. The easy handling of Hyalograft C in open surgery has suggested us to investigate its possible use by an arthroscopic procedure.

Arthroscopic technique has been used from December 2000 in 88 cases. At December 2003 45 patients achieved at least 1 year follow up and 22 patients – 2 years follow up.

All the patients were clinically evaluated was analyzed according to the International Repair Cartilage Society score at 12 and 24 months. Returning back to sport was also recorded. We were able to obtain CT scans or MRI images for all patients at 6, 12 and 24 months of follow up.

No complications related to the implant and no serious adverse events were observed during the treatment and follow up period. The IKDC objective score improved after 12 months in all patients, showing a normal or nearly normal knee in 96,7% of patients. The mean IKDC subjective score obtained was 41,3 at baseline, 76.9 at the 12 months follow-up control, and 75,9 after 24 months. The worsening of IKDC score was noted in 1 of 22 patients analyzed at 12 and 24 months follow up.

A second look arthroscopy was performed in 11 patients at 12 months follow up and a complete healing of the defect and the excellent quality of regenerated cartilage was noted at macroscopic examination. The histological evaluation in 6 cases has demonstrated the hyaline type of new cartilage, although not completely mature.

This matrix autologous chondrocyte transplantation procedure avoids the use of periosteal flap, simplify the surgical procedure and permit to perform the arthroscopic implant. Thus, complications as hypertrophy or ossification of periosteal flap are avoided and the surgical morbidity and the recovery time for the patient are extremely reduced. The preliminary clinical and histological results are encouraging but the decree absolute on the efficiency of this method will be assessed at longer follow up.