The past ten years have brought plenty of research and technical innovations and also preliminary clinical success in cartilage repair. The common target of all methods utilised is to produce a sufficiently stable quality of cartilage repair or regenerate. However, yet today clinical, radiological and histological results analysing the different techniques are somewhat contradictory. The different lines of clinically applied and basic research have focused on:. 1) Spontaneous natural filling of the defect with fibro-cartilage of variable solidity. - Abrasion chondroplasty, drilling or microfracturing to allow for mobilisation of progenitor cells and mesenchymal stem cells from the cancellous bone into the defect and develop to a hyaline like cartilage. - Stem cell treatment (in vivo or ex vivo theory of potential technique by which stem cells could be brought to a defect to create cartilage; so far no directly linked product available). 2) Transplantation of osteochondral auto grafts (Mosaicplasty, OATS, SDS, patellar graft) or allograft. 3a) Autologous chondrocyte transplantation and periosteal coverage (ACT) to cover bigger surfaces. 3b) Implantation of second and third generation ex vivo products and create less morbidity but without knowing whether the results are as long-lasting as for the originally described technique (chondrocytes cultured on membranes, MACI, in gels, implantation of a stable three-dimensional de novo cartilage disk or even engineered osteochondral grafts, AMIC: autologous membrane induced chondrogenesis). A fair amount of today’s laboratory research is focusing on the culture of the patients own chondrocytes or his own stem cells. Clinically, some methods can be applied in all indications regardless of size, localisation, depth of the lesion up to the age of fifty years and this is valid for lesions in the knee, the shoulder, the talus, the elbow etc. Other methods like AOCT should not be used for lesions over 2cm in diameter because of donor side morbidity. All methods claim to have an 85% outcome success rate. Regarding the histological content of the successful implants or the reformed cartilage, microfracturing produces a cartilage implant containing a fibrocartilage that looks similar to the hyaline like cartilage of ACI at two years. Mosaicplasty plugs provided great care is applied during insertion avoiding damage of the cylinders and cartilage death-a special instrumentation has been developed with ZIMMER, the Soft Delivery System, SDS to avoid force during impaction. They remain hyaline provided they are inserted without being prone or deep sunken and the surface convexity of the femoral condyle is restored and provided they are inserted tightly next to each other. There is agreement that this is more difficult in arthroscopic techniques. One agrees also that results are dependent on the alignment of the limb. If the compartment treated is overloaded, there is less chance for integration. Osteotomy has therefore a solid position in the armamentarium of the cartilage surgeon- up to 50% of our cases get an osteotomy as part of their treatment regardless of which technique is utilised. As complications in autologous osteochondral grafting we may observe destruction of the hyaline cartilage cap, non integration and pseudarthrosis or fractures of the cylinders (of special risk are smokers), especially when grafts are not inserted tightly to each other and there is lack of stability with fluid leakage out of the cartilage caps. Rarely ossification of the cartilage is observed when a thin capped cylinder retrieved in the peripheral zone of the femoral trochlea is implanted in an area of thick cartilage as in the centre of the patella where the cartilage is 5 mm thick. Donor site pathology in mosaicplasty is an issue of concern mainly if more than six plugs are removed from the femoropatellar joint. This alone can create clinical symptoms. Nicotine abuse, probably for all techniques decreases the rate of success of cartilage repair or regeneration and osteotomy healing. Roughly 300 cases have been treated during the last 10 years. The results were reported in 2002. As an alternate single surgery technique to microfracturing and mosaicplasty we adopted the “Autologous membrane induced chondrogenesis” (AMIC) technique proposed by Behrens that we find especially useful in OCD. In this relatively young technique we curette the defect and apply microfractures to the basis of the osseous defect. Then we gain cancellous bone from the tibial plateau and mix it with fibrin glue, of which 50% of the thrombin portion is replaced by the serum of the patient as a source of growth factor. This paste of bone and enriched fibrin glue is filled in the defect which is then covered by the porcine Chondrogide membrane (Geistlich) that is glued on and which we can as well suture to the defect. The AMIC technique in combination with microfractures can be utilised for the coverage of pure cartilage defects alone where the membrane is glued alone or fixed on the defect in combination with 5-0 resorbable sutures. In the first two weeks following surgery, after treatment is very defensive to avoid loss of the membrane. After two months of crutch walking with 15 kg of weight we observe a nice osseous integration of the graft and a covering layer that looks promising. After 4–6 months activity can be increased depending on the size of the defect. This is a young technique that we adopted in mid 2003 with 30 cases treated so far, therefore strict observation is required over the upcoming years regarding clinical results and durability and also the composition of this neocartilage. So far it seems to be an interesting alternative to Mosaicplasty since it combines principles of cell therapy with an artificial and instant biological containment that acts against the loss of cells thus acting as a internal bioreactor with the patients own growth factor support

This systematic review examines the current literature regarding surgical techniques for restoring articular cartilage in the hip, from the older microfracture techniques involving perforation to the subchondral bone, to adaptations of this technique using nanofractures and scaffolds. This review discusses the autologous and allograft transfer systems and the autologous matrix-induced chondrogenesis (AMIC) technique, as well as a summary of the previously discussed techniques, which could become common practice for restoring articular cartilage, thus reducing the need for total hip arthroplasty. Using the British Medical Journal Grading of Recommendations, Assessment, Development and Evaluation (BMJ GRADE) system and Grade system. Comparison of the studies discussed shows that microfracture has the greatest quantity and quality of research, whereas the newer AMIC technique requires more research, but shows promise. Cite this article: W. E. Hotham, A. Malviya. A systematic review of surgical methods to restore articular cartilage in the hip. Bone Joint Res 2018;7:336–342. DOI: 10.1302/2046-3758.75.BJR-2017-0331

PURPOSE. Recently, in tissue engineering several methods using stem cells have been developed to repair chondral and osteochondral defects. Most of these methods rely on the use of scaffolds. Studies in the literature have demonstrated, first in animals and then in humans, that the use of mesenchymal stem cells withdrawn by several methods from adipose tissue allows to regenerate hyaline articular cartilage. In fact, it has been cleared that adipose-derived cells have multipotentiality equivalent to bone marrow-derived stem cells and that they can very easily and very quickly be isolated in large amounts enabling their immediate use in operating room for one-step cartilage repair techniques. The purpose of this study is to evaluate the therapeutic effect of adipose-derived stem cells on cartilage repair and present our experience in the treatment of knee cartilage defects by the novel AMIC REPAIR TECHNIQUE AUGMENTED by immersing the collagen scaffold with mesenchymal stem cells withdrawn from adipose tissue of the abdomen. MATERIALS AND METHODS. Fat tissue processing involves mechanical forces and does not mandatorily require any enzymatic or chemical treatment in order to obtain the regenerative cells from the lipoaspirate. In our study, mesenchymal adipose stem cells were obtained by non-enzymatic filtration or microfragmentation of lipoaspirates of the abdomen adipose tissue that enabled the separation of the stromal vascular fraction and were used in one-step reconstruction of knee cartilage defects by means of this new AUGMENTED AMIC TECHNIQUE. The focal defects underwent bone marrow stimulation microfractures, followed by coverage with collagen double layer resorbable membrane (Chondro-gide. TM. -Geistlich Pharma AG, Wolhusen, Switzerland) soaked in the cells obtained from fat in 18 patients, aged between 31 and 58 years, at the level of the left knee in 10 cases and in the right in eight, with follow-up ranging between 12 and 36 months. RESULTS: Surgical procedures have been completed without technical problems neither intraoperative or early postoperative complications. The evaluation scores (IKDC, KOOS and VAS) showed a significant improvement, more than 30%, at the initial 6 months follow-up and furtherly improved in the subsequent follow-ups. Also the control MRIs showed a progressive filling and maturation of the repair tissue of the defects. CONCLUSIONS. Since we are reporting a short and medium-term experience, it is not, of course, possible to provide conclusive assessment considerations on this technique, as the experience has to mature along with the progression of follow-ups. The simplicity together with the absence of intraoperative difficulties or immediate complications and the experience gained by other authors, first in animals and then in early clinical cases, makes it, however, possible to say that this can be considered one of the techniques to which resort for one-step treatment of cartilage defects in the knee because it improves patient's conditions and has the potential to regenerate hyaline-like cartilage. Future follow-up works will confirm the results