André Kuhn

Regenerative potential of the cartilaginous tissue in mesenchymal stem cells: update, limitations, and challenges

Advances in the studies with adult mesenchymal stem cells (MSCs) have turned tissue regenerative therapy into a promising tool in many areas of medicine. In orthopedics, one of the main challenges has been the regeneration of cartilage tissue, mainly in diarthroses. In the induction of the MSCs, in addition to cytodifferentiation, the microenvironmental context of the tissue to be regenerated and an appropriate spatial arrangement are extremely important factors. Furthermore, it is known that MSC differentiation is fundamentally determined by mechanisms such as cell proliferation (mitosis), biochemical-molecular interactions, movement, cell adhesion, and apoptosis. Although the use of MSCs for cartilage regeneration remains at a research level, there are important questions to be resolved in order to make this therapy efficient and safe. It is known, for instance, that the expansion of chondrocytes in cultivation, needed to increase the number of cells, could end up producing fibrocartilage instead of hyaline cartilage. However, the latest results are promising. In 2014, the first stage I/II clinical trial to evaluate the efficacy and safety of the intra-articular injection of MSCs in femorotibial cartilage regeneration was published, indicating a decrease in injured areas. One issue to be explored is how many modifications in the articulate inflammatory environment could induce differentiation of MSCs already allocated in that region. Such issue arose from studies that suggested that the suppression of the inflammation may increase the efficiency of tissue regeneration. Considering the complexity of the events related to the chondrogenesis and cartilage repair, it can be concluded that the road ahead is still long, and that further studies are needed.

Viscosupplementation for treating knee osteoarthrosis: review of the literature

The aim here was to evaluate the evidence that might support or refute the use of intra-articular viscosupplementation in treating patients with symptomatic knee osteoarthrosis. A review of the literature was conducted using the Medline, PubMed and Cochrane Controlled Trial Register databases and Cochrane database systematic reviews (Cochrane Library). Only studies presenting a high level of evidence were taken into consideration. This study included analysis on randomized clinical trials that included at least 100 patients in each intervention group, meta-analyses and systematic reviews. Two meta-analyses, five systematic reviews and six randomized clinical trials fulfilled the inclusion criteria for this review. In the light of the best evidence available so far, there is no consensus for indicating or even for contraindicating the use of intra-articular viscosupplementation among patients with symptomatic knee osteoarthrosis (level of evidence I and degree of recommendation A). Further studies with appropriate methodology are needed to elucidate this matter.

Análise radiológica do posicionamento dos túneis ósseos na cirurgia de reconstrução do ligamento cruzado anterior: comparação entre as técnicas aberta e artroscópica via portal anteromedial

OBJETIVO: Avaliar e comparar o posicionamento dos tuneis osseos na cirurgia de reconstrucao do ligamento cruzado anterior (LCA) pela tecnica artroscopica e pela tecnica aberta atraves da artrotomia. METODO: Foi realizado um estudo retrospectivo comparativo de 70 pacientes acometidos por lesao do LCA. Trinta e cinco pacientes foram submetidos a reconstrucao do LCA por via aberta e 35 por via artroscopica utilizando a tecnica via portal anteromedial. Todos os pacientes foram submetidos a reconstrucao do LCA usando enxerto autologo do terco central do tendao patelar fixado com parafusos de interferencia. As radiografias pos-operatorias foram revisadas e o posicionamento do tunel femoral foi avaliado pelos metodos propostos por Harner e Aglietti, enquanto o tunel tibial foi avaliado pelo metodo proposto por Staubli e Rauschning. RESULTADOS: Foram observados 54 pacientes do sexo masculino e 16 do sexo feminino. A media de idade na ocasiao do procedimento foi de 34 anos e tres meses, variando de 17 a 58 anos. A tecnica artroscopica mostrou-se mais precisa que a tecnica aberta quanto ao posicionamento dos tuneis osseos, tanto femoral quanto tibial. CONCLUSAO: Atraves da analise radiologica dos joelhos submetidos a reconstrucao do LCA, observou-se que o posicionamento dos tuneis osseos, tanto femoral quanto tibial, apresenta menor variacao quando a cirurgia e feita pela via artroscopica.

Reconstruction of the anterior cruciate ligament in skeletally immature patients: an individualized approach,

Objective to evaluate a series of skeletally immature patients who underwent three surgical techniques for anterior cruciate ligament (ACL) reconstruction according to each patients growth potential. Methods a series of 23 skeletally immature patients who underwent ACL reconstruction surgery at ages ranging from 7 to 15 years was evaluated prospectively. The surgical technique was individualized according to the Tanner sexual maturity score. The surgical techniques used were transphyseal reconstruction, partial transphyseal reconstruction and extraphyseal reconstruction. Four patients underwent the extraphyseal technique, seven the partial transphyseal technique and twelve the full transphyseal technique, on the ACL. The postoperative evaluation was based on the Lysholm score, clinical analysis on the knee and the presence of angular deformity or dysmetria of the lower limb. Results the mean Lysholm score was 96.34 (±2.53). None of the patients presented differences in length and/or clinical or radiographic misalignment abnormality of the lower limbs. Conclusion ACL reconstruction using flexor tendon grafts in skeletally immature patients provided satisfactory functional results. Use of individualized surgical techniques according to growth potential did not give rise to physeal lesions capable of causing length discrepancies or misalignments of the lower limbs, even in patients with high growth potential.

Reconstruction of the anterior cruciate ligament by means of an anteromedial portal and femoral fixation using Rigidfix

Objective To evaluate a series of patients who underwent surgery for reconstruction of the anterior cruciate ligament with flexor tendons, by means of the anteromedial transportal technique using Rigidfix for femoral fixation, and to analyze the positioning of the pins by means of tomography. Methods Thirty-two patients were included in the study. The clinical evaluation was done using the Lysholm, subjective IKDC and Rolimeter. All of them underwent computed tomography with 3D reconstruction in order to evaluate the entry point and positioning of the Rigidfix pins in relation to the joint cartilage of the lateral condyle of the femur. Results The mean Lysholm score obtained was 87.81 and the subjective IKDC was 83.72. Among the 32 patients evaluated, 43% returned to activities that were considered to be very vigorous, 9% vigorous, 37.5% moderate and 12.5% light. In 16 patients (50%), the distal entry point of the Rigidfix pin was located outside of the cartilage (extracartilage); in seven (21.87%), the distal pin injured the joint cartilage (intracartilage); and in nine (28.12%), it was at the border of the lateral condyle of the femur. Conclusion The patients who underwent ACL reconstruction by means of the anteromedial transportal using the Rigidfix system presented satisfactory clinical results over the length of follow-up evaluated. However, the risk of lesions of the joint cartilage from the distal Rigidfix pin needs to be taken into consideration when the technique via an anteromedial portal is used. Further studies with larger numbers of patients and longer follow-up times should be conducted for better evaluation.

RADIOLOGICAL ANALYSIS OF BONE TUNNEL POSITION IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION SURGERY: COMPARISON BETWEEN THE OPEN TECHNIQUE AND ARTHROSCOPY VIA AN ANTEROMEDIAL PORTAL.

Objectives: To evaluate and compare bone tunnel positioning in anterior cruciate ligament (ACL) reconstruction surgery using the arthroscopic technique and the open technique consisting of arthrotomy. Method: A comparative retrospective study on 70 patients with ACL lesions was conducted. Thirty-five patients underwent ACL reconstruction by means of the open technique and 35 by means of the arthroscopic technique using an anteromedial portal. All the patients underwent ACL reconstruction using an autologous graft from the middle third of the patellar tendon, fixed using interference screws. The postoperative radiographs were reviewed and the positioning of the femoral tunnel was evaluated using the methods proposed by Harner et al. and Aglietti et al., while the tibial tunnel was assessed using the method proposed by Rauschning and Stäubli. Results: Fifty-four of the patients were male and 16 were female. Their mean age at the time of the procedure was 34 years and 3 months, with a range from 17 to 58 years. The arthroscopic technique was shown to be more accurate than the open technique for positioning both the femoral and the tibial bone tunnels. Conclusions: Radiological analysis on the knees subjected to ACL reconstruction showed that the positioning of both the femoral and the tibial bone tunnels presented less variation when the surgery was performed arthroscopically.