Arthroscopic Treatment of Acetabular Cartilage Lesions in Cam-Type Hip Impingement with Membrane Induced Chondrogenesis versus Microfracturing

We report on a consecutive series of patients with cam type FAI （femoro-acetabular impingement） with acetabular cartilage rim lesions larger than 150 mm2 that were treated with an arthroscopic AMIC （Autologous Matrix Induced Chondrogenesis） procedure and compared these patients to a matched cohort of patients who underwent an arthroscopic microfractufing. The AMIC group consisted 16 patients with a mean age of 34. Mean follow up is 38 months. Sixteen age and sex controlled patients who underwent an arthroscopic microfractufing of a similar size cartilage lesion were used as a comparative study group with a mean follow up of 41 months. No complications and no adverse reactions were seen, and all patients would have the same surgery again. We report 2 failures in the AMIC group with conversion to THR （Total Hip Replacement） at 8 and 36 months, respectively. In the microfracturing group, there were 3 conversions to THR after 12, 14 and 24 months. The HHS （Harris Hip Score） was 96.5 in the AMIC group and 93.5 in the microfracturing group. Patients had significantly less symptomatic synovitis postoperatively in the AMIC group and more athletes could resume their activities to the pre-injury level in this group. In conclusion, AMIC offers promising results in the treatment of cartilage lesions in patients with cam-type FAI.

New Classification and Visual Analysis of the Patella Cartilage during Total Knee Replacement

Objective: The aim of this prospective study is to evaluate how much damage the patellar cartilage presents during a total knee replacement. Methods: The damage of the articular patellar surface was analysed by visual inspection and photographs in 354 primary total knee replacements. The authors graded the degree of cartilage lesion in five groups. The cartilage status was analyzed and correlated with age, gender, side, body mass index (BMI), Kellgren-Lawrence radiographic scale and axial deviation. Results: After statistical analysis, we concluded: there was no evidence of an association between patellar arthrosis and age gender, side, weight and deformity. Conclusions: Articular cartilage was damaged in all 354 knees. Important subchondral bone exposure occurred in 274 knees (77.4%). Obese patients had more severe patellar osteoarthritis.

ALK5 transfection of bone marrow mesenchymal stem cells to repair osteoarthritis of knee joint

Previous studies have suggested that the transforming growth factor-β receptor ALK5 is crucial for articular chondrogenesis by bone marrow mesenchymal stem cells. Here, the wild-type ALK5 plasmids were mutated by overlapping extended PCR and transfected into bone marrow mesenchymal stem cells. The knee joint osteoarthritis mouse model was constructed by cutting oft＂ the anterior cruciate ligament and divided into three groups： saline group, bone marrow mesenchymal stem cells and ALK5-transfected bone marrow mesenchymal stem cells group. HE staining showed that the articular cartilage lesions were more serious of saline group compared with that of mesenchymal stem cell group, and this trend was more pronounced as time goes on. Immunohistochemical staining showed that although the expression level of type II collagen in all three groups down-regulated gradually upon time, its expression in ALK5-transfected bone marrow mesenchymal stem cells group was significantly enhanced compared with the other two groups. Micro-CT also suggested that ALK5 transfection of mouse bone marrow mesenchymal stem cells would promote repairing the knee cartilage lesions with arthritis of the mice. Although the osteoarthritis mechanism underlying a variety of factors work together, and the appropriate proportion of ALKS/ALK1 was also emphasized for the treatment of osteoarthritis. This work therefore demonstrated that ALK5 transfection of bone marrow mesenchymal stem cells could be a promising stem cell therapy for repair of cartilage lesions.

Instructive cartilage regeneration modalities with advanced therapeutic implantations under abnormal conditions

The development of interdisciplinary biomedical engineering brings significant breakthroughs to the field of cartilage regeneration.However,cartilage defects are considerably more complicated in clinical conditions,especially when injuries occur at specific sites(e.g.,osteochondral tissue,growth plate,and weight-bearing area)or under inflammatory microenvironments(e.g.,osteoarthritis and rheumatoid arthritis).Therapeutic implantations,including advanced scaffolds,developed growth factors,and various cells alone or in combination currently used to treat cartilage lesions,address cartilage regeneration under abnormal conditions.This review summarizes the strategies for cartilage regeneration at particular sites and pathological microenvironment regulation and discusses the challenges and opportunities for clinical transformation.