Articular cartilage is a nearly frictionless system with unique biomechanical properties. Unfortunately, its intrinsic reparative process cannot cope with full-thickness injuries. The current reparative or restorative procedures provide an opportunity to return the surface to its normal or near normal status. At present, autologous cell therapies, growth factor techniques and biomaterials offer a more promising avenue of research to find clinical answers. We should always remember that many other factors can influence the necessity of treating these defects such as accompanying joint abnormalities, body weight, and activity level. Treatment options used should be suitable for the special patient and familiar to the treating surgeon. Most of these patients will return to functional activity or sports, but some of them will require life-long modification of their daily activities.
Treatment of chondral lesions:
A- Conservative.
B- Operative:
• Arthroscopic lavage and debridement.
• Marrow tapping techniques.
• Abrasion arthroplasty.
• Subchondral drilling.
• Microfracture.
• Osteochondral autografting—mosaicoplasty.
• Osteochondral allografting.
• Autologous cell techniques.
• ACI & MACI.
• Growth factors & gene theraby
Microfracture alone has been used as the technique to which other treatment methods have been compared. It offers good initial results, although the effectiveness of this procedure may decrease beyond 5 years. It will likely play a role as an adjunct surgical technique to supplement other approaches. Grafts are a convenient but unreliable solution and their long-term viability remains a variable.
Among them, fresh autografts – as in mosaicplasty and OATS – are most commonly used and have shown good results clinically. These approaches transplant desirable hyaline cartilage, but the regenerated cartilage that knits together the gap between defect and implant is fibrous. Improving this may be a potential future advance to make autografts a more complete long-term solution. Fresh and frozen allografts are less commonly used, but clinical results with each approach are good.
Efforts to extend the life of functionality of these tissues in storage could make this approach more popular. Cell-based approaches, including ACI, are gaining popularity. The largest research efforts are being put into developing better culture techniques, matrices and implantation methods for harvested chondrocytes in an attempt to improve the overall hyaline cartilage profile of the implant, although long-term follow-up studies of these procedures are still lacking. Various products have and will be developed, which will need to be evaluated over the coming decade. Manipulating the development of these autologous chondrocytes is the most likely approach to mimic native tissue.
• Focal cartilage lesions can be effectively managed with a variety of procedures that provide good clinical outcomes.
• A variety of systems have been described for scoring of clinical outcomes after knee operations, disability due to lesion or arthritis, and overall subjective patient experience.
• Arthroscopic chondroplasty has received mixed results, with various studies showing excellent clinical outcomes, but a single randomized controlled trial involving this approach suggests that it is ineffective.
• Microfracture is a well-established procedure that is hypothesized to work by releasing growth-promoting factors and stem cells from the underlying bone into the damaged cartilage.
• Autografting cartilage through mosaicplasty restores desirable type 2 cartilage to the damaged surface, but some reports suggest deterioration at long-term follow-up.
• Allograft cartilage from either fresh or frozen tissues provide good early results, but the in vivo longevity of frozen grafts is questionable and fresh grafts have shown deterioration after 7 years.
• The equivalence or superiority of autologous chondrocyte implantation versus other established procedures has been demonstrated in several randomized clinical trials.
• Experimental treatments during the harvest, culture and implantation of autologous chondrocytes are aimed at improving the type 2 cartilage character (amount of type 2 cartilage) of regenerated tissue, and provides a rich avenue for future research. Nonbiological implants are rarely used in the treatment of focal cartilage defects and reports of their use are still mainly investigational.
Basic science advances have fueled the development of ACI and are promoting the development of new cartilage repair techniques. The benefit of these new strategies compared with established cartilage repair techniques is not yet established, and the promise of one-stage techniques that harness the potential of stem cells to create organized hyaline-like repair tissue in situ remains the elusive goal. As cartilage regeneration research matures, long-term follow-up and larger comparative trials will ultimately establish the optimal method for cartilage repair.
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