[Biologic Reconstruction of Full Sized Cartilage Defects of the Hip: A Guideline from the DGOU Group "Clinical Tissue Regeneration" and the Hip Committee of the AGA]. / Biologische Rekonstruktion lokalisiert vollschichtiger Knorpelschäden des Hüftgelenks: Empfehlungen der Arbeitsgemeinschaft "Klinische Geweberegeneration" der DGOU und des Hüftkomitees der AGA.

Background Symptomatic pre-arthritic deformities such as femoroacetabular impingement (FAI) or hip dysplasia often lead to localised cartilage defects and subsequently to osteoarthritis. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) and the hip committee of the AGA (German speaking Society for Arthroscopy and Joint Surgery) provides an overview of current knowledge of the diagnosis and surgical treatment of cartilage defects, in order to infer appropriate therapy recommendations for the hip. Methods Review of FAI and resultant cartilage damage in the hip as reported in published study findings in the literature and discussion of the advantages and disadvantages of different surgical procedures to preserve the joint. Results Most published studies on the surgical treatment of cartilage damage in the hip report defects caused by cam-type FAI at the acetabulum. Development of these defects can be prevented by timely elimination of the relevant deformities. At present, current full-thickness cartilage defects are mostly treated with bone marrow-stimulating techniques such as microfracture (MFx), with or without a biomaterial, and matrix-assisted autologous chondrocyte transplantation (MACT). Osteochondral autologous transplantation (OAT) is not the treatment of choice for isolated full-thickness chondral defects at the hip, because of the unfavourable risk-benefit profile. Due to the relatively short history of cartilage repair surgery on the hip, the studies available on these procedures have low levels of evidence. However, it is already becoming obvious that the experience gained with the same procedures on the knee can be applied to the hip as well. For example, limited healing and regeneration of chondral defects after MFx can also be observed at the hip joint. Conclusions The cartilage surface of the acetabulum, where FAI-related chondral lesions appear, is considerably smaller than the weight-bearing cartilage surface of the knee joint. However, as in the knee joint, MACT is the therapy of choice for full-thickness cartilage defects of more than 1.5 - 2 cm2. Minimally invasive types of MACT (e.g. injectable chondrocyte implants) should be preferred in the hip joint. In cases where a single-stage procedure is indicated or there are other compelling reasons for not performing a MACT, a bone marrow-stimulating technique in combination with a biomaterial covering is preferable to standard MFx. For treatment of lesions smaller than 1.5 - 2 cm2 the indication for a single-stage procedure is wider. As with defects in the knee, it is not possible to determine a definite upper age limit for joint-preserving surgery or MACT in the hip, as the chronological age of patients does not necessarily correlate with their biological age or the condition of their joints. Advanced osteoarthritis of the hip is a contraindication for any kind of hip-preserving surgery. Long-term observations and prospective randomised studies like those carried out for other joints are necessary.

[Coincidence and Therapy of Dysalignments and Degenerative Knee Cartilage Lesions. Results from the German CartilageRegistry DGOU]. / Koinzidenz und Therapie von Beinachsdeviationen bei degenerativen Knorpelschäden des Kniegelenks. Ergebnisse aus dem Deutschen KnorpelRegister DGOU.

Purpose This multicenter study was aimed to evaluate the coincidence of degenerative knee cartilage lesions with a varus or valgus dysalignment. Furthermore, the frequency of the combined surgery of cartilage treatments and corrective osteotomies are determined. Material and Methods A total of 1778 patients were included in the German CartilageRegistry (deadline 01.08.2016). In 90.6% of patients, the surgeon calculated the alignment by clinical observation. Varus or valgus conditions were measured radiologically in only 56.0%. This study describes patients who underwent treatment of degenerative cartilage lesions with a complete (clinical and radiological) determination of the alignment. Results The mean mechanical tibia-femur angle (Paley) (mTFA) in clinically neutral extremities was 0.2° (SD 0.6; 0 - 5), in varus cases 5,0° (SD 3.2; 0 - 15), and - 4.7° (SD - 4.0; - 15 - 0) in valgus cases. Varus dysalignment was significantly associated with cartilage lesions in the medial compartment. Valgus dysalignment more frequently occurred in knees with lateral cartilage lesions. Independently of the surgeon's choice of the method of cartilage surgery, in 72.4% of all valgus deformities a corrective osteotomy was performed. Valgus dysalignment was corrected in 50%. Conclusions In about a quarter of all cases, cartilage lesions are associated with a varus (18.9%) or valgus (4.2%) dysalignment. In a number of cases, the treatment of cartilage lesions should include the addressing of these axial deviations. Still the efficacy of this procedure regarding prognosis and clinical outcome is unclear.

Chondrogenesis of adipose-derived adult stem cells in a poly-lactide-co-glycolide scaffold.

Adult adipose-derived stem cells (ASCs) are considered to be an alternative cell source for cell-based cartilage repair because of their multiple differentiation potentials. This article addresses the chondrogenic differentiation of ASCs seeded into poly-lactide-co-glycolide (PLGA) scaffolds after implantation in a subcutaneous pocket of nude mice. Human ASCs were seeded into PLGA (polylactic acid:polyglycolic acid = 90:10) scaffolds and cultured in transforming growth factor beta 1 (TGF-beta1)-containing medium for 3 weeks in vitro. Then specimens were implanted into a subcutaneous pocket of severe combined immunodeficiency mice and harvested after 8 weeks. Chondrospecific messenger RNA (mRNA) expression was analyzed using reverse transcriptase polymerase chain reaction. Corresponding extracellular matrix (ECM) synthesis was demonstrated using immunohistochemical staining. Chondrospecific marker molecules such as collagen type II and type X, cartilage oligomeric matrix protein, and aggrecan subsequently increased during the 3 weeks period in vitro. After a further 8 weeks, in vivo samples pretreated with TGF-beta1 continued expressing collagen type II and aggrecan mRNA, and collagen type II was found within the ECM using immunohistochemistry. Chondrospecific mRNA was not detected in control samples. ASC-seeded PLGA scaffolds express a stable chondrogenic phenotype in a heterotopic model of cartilage transplantation and represent a suitable tool for tissue engineering of cartilage.