Matrix metalloproteinases and their clinical applications in orthopaedics.

Imbalance in the expression of matrix metalloproteinases and their inhibitors contribute considerably to abnormal connective tissue degradation prevalent in various orthopaedic joint diseases such as rheumatoid arthritis and osteoarthritis. Matrix metalloproteinase expression has been detected in ligament, tendon, and cartilage tissues in the joint. They are known to contribute to the development, remodeling, and maintenance of healthy tissue through their ability to cleave a wide range of extracellular matrix substrates. Their role has been extended to cell growth, migration, differentiation, and apoptosis. In orthopaedics, their clinical applications constantly are being explored. The multiple steps in matrix metalloproteinase regulation offer potential targets for inhibition, useful in drug therapy. The correlation between matrix metalloproteinases and progression in joint erosion presents potential prognostic and diagnostic tools in rheumatoid arthritis. Matrix metalloproteinases also can be incorporated into scaffold design to control the degradation rate of engineered tissue constructs. This current review aims to summarize and emphasize the importance of matrix metalloproteinases and their natural inhibitors in the maturation of musculoskeletal tissue through matrix remodeling and, therefore, in the generation of a new clinical potential in orthopaedics.