Mats Brittberg

Objectives: Damaged articular cartilage cannot regenerate spontaneously. Chondrocyte therapy, the current treatment of choice, requires laboratory expansion, necessitating two surgical procedures. Adding a second cell type to intraoperatively isolated chondrocytes enables single-stage chondrocyte-based repair strategies and has shown promise in vitro . The benefit of this strategy in vivo and in the clinic has not yet been comprehensively assessed. This systematic review assesses the efficacy of cartilage repair by co-implantations of chondrocytes with other cell types over all available in vivo studies. Design: Medline, Embase and Cochrane databases were searched for studies on co-implantations of chondrocytes with other cell types for hyaline cartilage repair. For each study, extracted data were tabulated and reporting quality and risk of bias were assessed. Studies were categorized based on their control groups for qualitative synthesis. Results: The search yielded 48 studies across 46 publications: 44 animal studies (26 ectopic and 18 orthotopic) and four clinical trials. Ectopic studies scored poorly on reporting quality and bias, while orthotopic studies were only moderately better. Twenty-seven of 27 experiments with chondrocyte-only controls demonstrated synergistic cartilage formation through co-implantation. Cartilage formation by co-implantations was also found in 15 of 17 experiments without such control and in four clinical trials. Conclusion: Cartilage repair by articular chondrocytes is improved by adding a second cell type, like mesenchymal stromal cells. This is likely caused by the second cell types’ stimulatory support. Other second cell types and chondrocyte sources have shown promising results too. This is encouraging for further clinical exploration of single-stage co-implantation strategies.

Objective: Viscosupplementation (VS) by intra-articular injections of hyaluronic acid (HA) is a commonly used treatment of knee osteoarthritis. However, there are no clear recommendations for its use in clinical situations not usually addressed in therapeutic guidelines. Design: Members of the European Viscosupplementation Consensus Group (EUROVISCO), made up of rheumatologists, orthopedic surgeons, and rehabilitation physicians from seven European countries, were asked to make a therapeutic decision on 30 clinical scenarios based on their clinical experience and data from the literature, using the Delphi method. For each scenario, the strength of agreement and the level of consensus were calculated by the chairman of the group. Results: The expert panel reached consensus on 18 of the 30 clinical scenarios proposed. According to the experts, the factors that most influence the decision to use VS with HA to treat knee osteoarthritis are the nature and severity of symptoms, the presence of comorbidity, the absence of therapeutic alternatives, and the patient’s refusal to undergo knee arthroplasty. Obesity and an advanced radiological degree of osteoarthritis have been identified as the two main factors for poor response to VS with HA and should be considered before any decision is made to viscosupplement. Conclusion: This set of recommendations, based on common clinical scenarios, is intended to help practitioners make decisions about HA VS in patients with osteoarthritis of the knee.

Intact articular cartilage plays a vital role in joint homeostasis. Local cartilage repairs, where defects in the cartilage matrix are filled in and sealed to congruity, are therefore important treatments to restore a joint equilibrium. The base for all cartilage repairs is the cells; either chondrocytes or chondrogeneic cells from bone, synovia and fat tissue. The surgical options include bone marrow stimulation techniques alone or augmented with scaffolds, chondrogeneic cell implantations and osteochondral auto‐ or allografts. The current trend is to choose one‐stage procedures being easier to use from a regulatory point of view. This narrative review provides an overview of the current nonoperative and surgical options available for the repair of various cartilage lesions.Level of Evidence: Level IV.