Augmentation Techniques for Meniscus Repair
Menisci display exquisitely complex structure and play an essential weight-bearing role in the knee joint. A torn meniscus is one of the most common knee injuries which can result in pain and mechanical abnormalities. Tear location is one aspect which determines the endogenous healing response; tears that occur in the peripheral densely vascularized zone of the meniscus have the potential to heal while the healing capacity is more limited in the less vascularized inner zones. Meniscectomy was once widely performed, but led to poor radiographic and patient-reported mid- and long-term outcomes. After the advent of arthroscopy, orthopaedic opinion in the 1980s has been swaying toward salvaging or repairing the torn meniscus tissue to prevent osteoarthritis rather than performing meniscectomy. Meniscus repair in young active individuals has been shown to be effective, reproducible, and reliable if indications are met; however, only a small proportion of all tears are considered repairable with available technologies. Biological augmentation techniques and meniscus tissue engineering strategies are being devised to enhance the likelihood and rate of healing in meniscus repair. Preclinical and clinical studies have shown that introduction of cellular elements of the blood, bone marrow, and related growth factors have the potential to enhance meniscus repair. This article reviews the current state of clinical management of meniscus tears (primary repair) as well as augmentation techniques to improve healing by meniscus wrapping with extracellular matrix materials, trephination, synovial rasping and abrasion, fibrin/blood clot placement, and platelet-rich plasma injections. In addition, the rationale for using polymer/autologous blood component implants to improve meniscus repair will be discussed.